U.S. patent application number 11/556756 was filed with the patent office on 2007-06-07 for apparatus and process for plasma-enhanced atomic layer deposition.
Invention is credited to Schubert S. Chu, Seshadri Ganguli, Paul Ma, Christophe Marcadal, Kavita Shah, Dien-Yeh Wu, Frederick C. Wu.
Application Number | 20070128862 11/556756 |
Document ID | / |
Family ID | 38801936 |
Filed Date | 2007-06-07 |
United States Patent
Application |
20070128862 |
Kind Code |
A1 |
Ma; Paul ; et al. |
June 7, 2007 |
APPARATUS AND PROCESS FOR PLASMA-ENHANCED ATOMIC LAYER
DEPOSITION
Abstract
Embodiments of the invention provide an apparatus configured to
form a material during an atomic layer deposition (ALD) process,
such as a plasma-enhanced ALD (PE-ALD) process. In one embodiment,
a showerhead assembly comprises a showerhead and a plasma baffle
that are used to disperse process gases within a plasma-enhanced
vapor deposition chamber. The showerhead plate comprises an inner
area configured to position the plasma baffle therein and an outer
area which has a plurality of holes for emitting a process gas. The
plasma baffle comprises a conical nose disposed on an upper surface
to receive another process gas, a lower surface to emit the process
gas and a plurality of openings configured to flow the process gas
from above the upper surface into a process region. The openings
are preferably slots that are positioned at predetermined angle for
emitting the process gas with a circular flow pattern.
Inventors: |
Ma; Paul; (Sunnyvale,
CA) ; Shah; Kavita; (Sunnyvale, CA) ; Wu;
Dien-Yeh; (San Jose, CA) ; Ganguli; Seshadri;
(Sunnyvale, CA) ; Marcadal; Christophe; (Santa
Clara, CA) ; Wu; Frederick C.; (Cupertino, CA)
; Chu; Schubert S.; (San Francisco, CA) |
Correspondence
Address: |
PATTERSON & SHERIDAN, L.L.P.
Suite 1500
3040 Post Oak Blvd.
Houston
TX
77056
US
|
Family ID: |
38801936 |
Appl. No.: |
11/556756 |
Filed: |
November 6, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60733870 |
Nov 4, 2005 |
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60733655 |
Nov 4, 2005 |
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60733654 |
Nov 4, 2005 |
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60733574 |
Nov 4, 2005 |
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60733869 |
Nov 4, 2005 |
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Current U.S.
Class: |
438/680 ;
257/715 |
Current CPC
Class: |
H01L 21/76844 20130101;
H01J 37/32623 20130101; C23C 16/5096 20130101; H01J 37/32082
20130101; C23C 16/45544 20130101; H01J 37/32633 20130101; C23C
16/45553 20130101; H01L 21/76873 20130101; H01L 21/76846 20130101;
C23C 16/45563 20130101; H01J 37/3244 20130101; H01J 37/32522
20130101; H01J 37/32449 20130101; H01L 2221/1089 20130101; C23C
16/45542 20130101; C23C 16/45565 20130101; C23C 16/45536 20130101;
H01L 2924/0002 20130101; C23C 16/18 20130101; C23C 16/509 20130101;
H01L 21/28562 20130101; H01L 2924/0002 20130101; H01L 2924/00
20130101 |
Class at
Publication: |
438/680 ;
257/715 |
International
Class: |
H01L 21/44 20060101
H01L021/44; H01L 23/34 20060101 H01L023/34 |
Claims
1. A plasma baffle assembly for receiving a process gas within a
plasma-enhanced vapor deposition chamber, comprising: a plasma
baffle plate containing an upper surface to receive a process gas
and a lower surface to emit the process gas; a plurality of
openings configured to flow the process gas from above the upper
surface to below the lower surface, wherein each opening is
positioned at a predetermined angle of a vertical axis that is
perpendicular to the lower surface; and a conical nose cone on the
upper surface.
2. The plasma baffle assembly of claim 1, wherein the plurality of
openings is a plurality of slots.
3. The plasma baffle assembly of claim 1, wherein the predetermined
angle is positioned to provide the process gas with a circular gas
flow pattern.
4. The plasma baffle assembly of claim 3, wherein the circular gas
flow pattern comprises a flow pattern selected from the group
consisting of vortex, helix, spiral, twirl, twist, coil, whirlpool,
and derivatives thereof.
5. The plasma baffle assembly of claim 2, wherein the predetermined
angle is within a range from about 20.degree. to about
70.degree..
6. The plasma baffle assembly of claim 5, wherein each slot of the
plurality of slots has a width within a range from about 0.60 mm to
about 0.90 mm.
7. The plasma baffle assembly of claim 6, wherein the plurality of
slots comprises about 10 slots or more.
8. The plasma baffle assembly of claim 6, wherein each slot of the
plurality of slots has a width to prohibit back diffusion of gas or
formation of a secondary plasma.
9. The plasma baffle assembly of claim 2, wherein the plasma baffle
plate comprises a conductive material selected from the group
consisting of aluminum, stainless steel, steel, iron, chromium,
nickel, alloys thereof, and combinations thereof.
10. The plasma baffle assembly of claim 9, wherein each of the
slots have an opening that extends across the upper surface between
the conical nose cone and an outer edge of the plasma baffle plate,
and the opening extends at an angle measured from a radius of the
upper surface.
11. The plasma baffle assembly of claim 10, wherein the angle is
tangential or substantially tangential to a point along the radius,
wherein a center of the upper surface and the point are at a
distance within a range from about 1 mm to about 3 mm.
12. The plasma baffle assembly of claim 10, wherein the angle is
tangential or substantially tangential to the conical nose
cone.
13. The plasma baffle assembly of claim 10, wherein the angle is
within a range from about 20.degree. to about 45.degree..
14. The plasma baffle assembly of claim 9, wherein the conical nose
cone has a flat upper surface.
15. The plasma baffle assembly of claim 9, wherein the conical nose
cone has a concave upper surface or a convex upper surface.
16. The plasma baffle assembly of claim 1, wherein the plurality of
openings is a plurality of holes.
17. The plasma baffle assembly of claim 16, wherein the
predetermined angle is positioned to provide the process gas
towards the vertical axis.
18. The plasma baffle assembly of claim 17, wherein the
predetermined angle is within a range from about 30.degree. to
about 40.degree..
19. The plasma baffle assembly of claim 16, wherein each hole of
the plurality of holes has a diameter on the upper surface of the
plasma baffle plate within a range from about 1.5 mm to about 2 mm
and a diameter on the lower surface of the plasma baffle plate
within a range from about 0.6 mm to about 1 mm.
20. The plasma baffle assembly of claim 19, wherein the plurality
of holes comprises about 4 holes or more.
21. The plasma baffle assembly of claim 1, wherein the plurality of
openings comprises a plurality of holes and a plurality of rounded
holes.
22. A plasma baffle assembly for receiving a process gas within a
plasma-enhanced vapor deposition chamber, comprising: a plasma
baffle plate containing an upper surface to receive a process gas
and a lower surface to emit the process gas; and a plurality of
openings configured to flow the process gas from above the upper
surface to below the lower surface, wherein each opening is
positioned at a predetermined angle not parallel from a
perpendicular axis of the lower surface.
23. A plasma baffle assembly for receiving a process gas within a
plasma-enhanced vapor deposition chamber, comprising: a plasma
baffle plate containing an upper surface to receive a process gas
and a lower surface to emit the process gas; and a plurality of
openings configured to flow the process gas from above the upper
surface to below the lower surface, wherein each opening is
positioned at a predetermined angle obscured from a perpendicular
axis of the lower surface.
24. A showerhead assembly for receiving a process gas within a
plasma-enhanced vapor deposition chamber, comprising: a showerhead
plate containing an upper surface to receive gases and a lower
surface to emit the gases; an inner area on the upper surface for
receiving a first process gas, wherein the inner area comprises a
first plurality of openings configured to flow the first process
gas from above the upper surface to below the lower surface; and an
outer area on the upper surface for receiving the second process
gas, wherein the outer area comprises a second plurality of
openings configured to flow the second process gas from above the
upper surface to below the lower surface.
25. A showerhead assembly for receiving a process gas within a
plasma-enhanced vapor deposition chamber, comprising: a showerhead
plate containing an upper surface to receive gases and a lower
surface to emit the gases; an inner area on the upper surface for
receiving a first process gas, wherein the inner area comprises at
least one opening configured to flow the first process gas from
above the upper surface to below the lower surface; an outer area
on the upper surface for receiving the second process gas, wherein
the outer area comprises a second plurality of openings configured
to flow the second process gas from above the upper surface to
below the lower surface; a cooling assembly positioned above and in
contact with the showerhead plate; an inner region between the
inner area and the cooling assembly; and an outer region between
the outer are and the cooling assembly.
26. The showerhead assembly of claim 25, wherein the lower surface
is shaped and sized to substantially cover a substrate receiving
surface.
27. The showerhead assembly of claim 26, wherein the inner region
of the showerhead plate comprises a plasma baffle.
28. The showerhead assembly of claim 27, wherein the plasma baffle
is removable from the showerhead plate.
29. The showerhead assembly of claim 27, wherein the showerhead
plate comprises a conductive material selected from the group
consisting of aluminum, stainless steel, steel, iron, chromium,
nickel, alloys thereof, and combinations thereof.
30. The showerhead assembly of claim 25, wherein the second
plurality of openings is a plurality of holes.
31. The showerhead assembly of claim 30, wherein each hole of the
plurality of holes has a diameter within a range from about 0.20 mm
to about 0.80 mm.
32. The showerhead assembly of claim 31, wherein the plurality of
holes comprises about 1,000 holes or more.
33. The showerhead assembly of claim 31, wherein each hole of the
plurality of holes has a diameter to prohibit back diffusion of gas
or formation of a secondary plasma.
34. The showerhead assembly of claim 25, wherein the cooling
assembly comprises a plurality of passageways for directing the
second process gas into the outer region.
35. The showerhead assembly of claim 34, wherein each passageway of
the plurality of passageways extends into the outer region at a
predetermined angle.
36. The showerhead assembly of claim 35, wherein the predetermined
angle prohibits back diffusion of gas or formation of a secondary
plasma.
37. The showerhead assembly of claim 35, wherein the predetermined
angle is within a range from about 15.degree. to about
35.degree..
38. The showerhead assembly of claim 34, wherein each passageway of
the plurality of passageways provides an obscured flow path for the
second process gas into the outer region.
39. The showerhead assembly of claim 34, wherein the plurality of
passageways comprises at least about 10 channels.
40. The showerhead assembly of claim 25, wherein the at least one
opening comprises a first plurality of openings configured to flow
the first process gas from above the upper surface to below the
lower surface.
41. The showerhead assembly of claim 40, wherein the first
plurality of openings is a plurality of slots.
42. The showerhead assembly of claim 41, wherein the plurality of
slots is positioned at a predetermined angle measured from a
perpendicular axis of the lower surface.
43. The showerhead assembly of claim 42, wherein the predetermined
angle is within a range from about 20.degree. to about
70.degree..
44. The showerhead assembly of claim 43, wherein each slot of the
plurality of slots has a width within a range from about 0.60 mm to
about 0.90 mm.
45. The showerhead assembly of claim 43, wherein the plurality of
slots comprises about 10 slots or more.
46. The showerhead assembly of claim 44, wherein each slot of the
plurality of slots has a width to prohibit back diffusion of gas or
formation of a secondary plasma.
47. A showerhead assembly for conducting a vapor deposition
process, comprising: a showerhead plate having a bottom surface to
substantially cover a substrate receiving surface within a process
chamber; an inner region of the showerhead plate for distributing a
first process gas through a plurality of slots positioned at a
predetermined injection angle relative to the substrate receiving
surface; and an outer region of the showerhead plate for
distributing a second process gas through a plurality of holes.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of co-pending U.S. Ser. No.
60/733,870 (10429L), filed Nov. 4, 2005, U.S. Ser. No. 60/733,655
(10429L.02), filed Nov. 4, 2005, U.S. Ser. No. 60/733,654
(10429L.03), filed Nov. 4, 2005, U.S. Ser. No. 60/733,574
(10429L.04), filed Nov. 4, 2005, and U.S. Ser. No. 60/733,869
(10429L.05), filed Nov. 4, 2005, which are all incorporated herein
by reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] Embodiments of the invention generally relate to an
apparatus and a method for depositing materials, and more
particularly to an atomic layer deposition chamber configured to
deposit a material during a plasma-enhanced process.
[0004] 2. Description of the Related Art
[0005] In the field of semiconductor processing, flat-panel display
processing or other electronic device processing, vapor deposition
processes have played an important role in depositing materials on
substrates. As the geometries of electronic devices continue to
shrink and the density of devices continues to increase, the size
and aspect ratio of the features are becoming more aggressive,
e.g., feature sizes of 0.07 .mu.m and aspect ratios of 10 or
greater. Accordingly, conformal deposition of materials to form
these devices is becoming increasingly important.
[0006] While conventional chemical vapor deposition (CVD) has
proved successful for device geometries and aspect ratios down to
0.15 .mu.m, the more aggressive device geometries require an
alternative deposition technique. One technique that is receiving
considerable attention is atomic layer deposition (ALD). During an
ALD process, reactant gases are sequentially introduced into a
process chamber containing a substrate. Generally, a first reactant
is pulsed into the process chamber and is adsorbed onto the
substrate surface. A second reactant is pulsed into the process
chamber and reacts with the first reactant to form a deposited
material. A purge step is typically carried out between the
delivery of each reactant gas. The purge step may be a continuous
purge with the carrier gas or a pulse purge between the delivery of
the reactant gases. Thermally induced ALD processes are the most
common ALD technique and use heat to cause the chemical reaction
between the two reactants. While thermal ALD processes work well to
deposit some materials, the processes often have a slow deposition
rate. Therefore, fabrication throughput may be impacted to an
unacceptable level. The deposition rate may be increased at a
higher deposition temperature, but many chemical precursors,
especially metal-organic compounds, decompose at elevated
temperatures.
[0007] The formation of materials by plasma-enhanced ALD (PE-ALD)
processes is also a known technique. In some examples of PE-ALD
processes, a material may be formed from the same chemical
precursors as a thermal ALD process, but at a higher deposition
rate and a lower temperature. Although several variations of
techniques exist, in general, a PE-ALD process provides that a
reactant gas and a reactant plasma are sequentially introduced into
a process chamber containing a substrate. The first reactant gas is
pulsed into the process chamber and is adsorbed onto the substrate
surface. Thereafter, the reactant plasma is pulsed into the process
chamber and reacts with the first reactant gas to form a deposited
material. Similarly to a thermal ALD process, a purge step may be
conducted between the delivery of each of the reactants. While
PE-ALD processes overcome some of the shortcomings of thermal ALD
processes due to the high degree of reactivity of the reactant
radicals within the plasma, PE-ALD processes have many limitations.
PE-ALD process may cause plasma damage to a substrate (e.g.,
etching), be incompatible with certain chemical precursors and
require additional hardware.
[0008] Therefore, there is a need for an apparatus and a process
for depositing or forming a material on a substrate by a vapor
deposition technique, preferably by a plasma-enhanced technique,
and more preferably, by a PE-ALD technique.
SUMMARY OF THE INVENTION
[0009] Embodiments of the invention provide an apparatus configured
to form a material during an atomic layer deposition (ALD) process,
such as a plasma-enhanced ALD (PE-ALD) process. In one embodiment,
a process chamber is configured to expose a substrate to a sequence
of gases and plasmas during a PE-ALD process. The process chamber
contains components that are capable of being electrically
insulated, electrically grounded or RF energized. In one example, a
chamber body and a gas manifold assembly are grounded and separated
by electrically insulated components, such as an insulation cap, a
plasma screen insert and an isolation ring. A showerhead, a plasma
baffle and a water box are positioned between the insulated
components and become RF hot when activated by a plasma
generator.
[0010] In one example, a chamber for processing substrates is
provided which includes a substrate support having a substrate
receiving surface and a chamber lid assembly with a process region
contained therebetween. In one embodiment, the chamber lid assembly
contains a showerhead assembly having an inner region and an outer
region, a cooling assembly in contact with the showerhead assembly,
a plasma baffle disposed within the inner region of the showerhead
assembly, a plasma screen disposed above the showerhead assembly
and configured to direct a first process gas to the plasma baffle
and a second process gas to the outer region of the showerhead
assembly, a first gas region located between the plasma baffle and
the plasma screen and a second gas region located between the outer
region of the showerhead assembly and the cooling assembly.
[0011] In another example, a chamber for processing substrates is
provided which includes a substrate support having a substrate
receiving surface and a chamber lid that contains a channel at a
central portion of the chamber lid. A tapered bottom surface
extending from the channel to a plasma screen disposed above a
plasma baffle and a showerhead, wherein the showerhead is shaped
and sized to substantially cover the substrate receiving surface, a
first conduit coupled to a first gas inlet within the channel and a
second conduit coupled to a second gas inlet within the channel,
wherein the first conduit and the second conduit are positioned to
provide a gas flow in a circular direction.
[0012] In another example, a chamber for processing substrates is
provided which includes a substrate support having a substrate
receiving surface, a chamber lid assembly contains a showerhead
assembly having an inner region and an outer region, a plasma
screen disposed above the showerhead assembly and configured to
direct a first process gas to the inner region and a second process
gas to the outer region and a process region situated between the
substrate receiving surface and the chamber lid assembly. The
plasma screen contains an inner area for receiving the first
process gas and an outer area for receiving the second process
gas.
[0013] In another embodiment, a lid assembly is configured to
expose a substrate to a sequence of gases and plasmas during a
PE-ALD process. The lid assembly contains components that are
capable of being electrically insulated, electrically grounded or
RF energized. In one example, the lid assembly contains a grounded
gas manifold assembly positioned above electrically insulated
components, such as an insulation cap, a plasma screen insert and
an isolation ring. A showerhead, a plasma baffle and a water box
are positioned between the insulated components and become RF hot
when activated by a plasma generator.
[0014] In one example, the showerhead assembly contains a
showerhead plate having a lower surface to substantially cover the
substrate receiving surface. The inner region of the showerhead
assembly contains the plasma baffle as a removable component. The
showerhead assembly and the plasma baffle usually contain a
conductive material, such as aluminum, stainless steel, steel,
iron, chromium, nickel, alloys thereof or combinations thereof.
Also, the lower surface of the showerhead plate and the plasma
baffle are positioned parallel or substantially parallel to the
substrate receiving surface and are connected to an electrical
source for igniting a plasma. The outer region of the showerhead
assembly contains a plurality of holes in fluid communication with
the process region. Each of the holes may have a diameter within a
range from about 0.20 mm to about 0.80 mm, preferably, from about
0.40 mm to about 0.60 mm, such as about 0.51 mm. The showerhead
plate may contain about 1,000 holes or more, such as about 1,500
holes or more. The holes have a diameter to prohibit back diffusion
of gas or to prohibit formation of a secondary plasma.
[0015] In another example, a lid assembly for conducting a vapor
deposition process within a process chamber is provided which
includes an insulation cap containing a first channel configured to
flow a first process gas and a plasma screen having an upper
surface with an inner area and an outer area. The insulation cap
may be positioned on the upper surface of the plasma screen. A
first plurality of openings within the inner area of the plasma
screen is configured to direct the first process gas from above the
upper surface to below a lower surface and a second plurality of
openings within the outer area of the plasma screen is configured
to flow a second process gas from above the upper surface to below
the lower surface. In one example, the first plurality of openings
contains holes and the second plurality of openings contains slots.
Also, the insulation cap may contain a second channel configured to
flow the second process gas to the outer area of the plasma screen.
The inner area of the plasma screen contains a zone free of holes
and a first flow pattern of the first process gas is directional at
a line-of-sight to the zone. The line-of-sight of the first flow
pattern is directional obscure to the plurality of holes so to
prohibit a secondary plasma from igniting above the upper surface
of the plasma screen. In one example, each of the holes have a
diameter within a range from about 0.5 mm to about 5 mm,
preferably, from about 1 mm to about 3 mm, and more preferably,
about 1.5 mm. The plurality of holes may contain at least about 100
holes, preferably at least about 150 holes. The insulation cap and
the plasma screen may each be formed from a material that is
electrically insulating, thermally insulating or electrically and
thermally insulating, such as a ceramic material, a quartz material
or a derivative thereof.
[0016] In another embodiment, a showerhead assembly contains a
showerhead and a plasma baffle for dispersing process gases within
a plasma-enhanced vapor deposition chamber. The showerhead plate
contains an inner area configured to position the plasma baffle
therein and an outer area which has a plurality of holes for
emitting a process gas. The plasma baffle contains a conical nose
disposed on an upper surface to receive another process gas, a
lower surface to emit the process gas and a plurality of openings
configured to flow the process gas from above the upper surface
into a process region. The openings are preferably slots that are
positioned at predetermined angle for emitting the process gas with
a circular flow pattern.
[0017] In one example, the plasma baffle assembly contains a
plurality of slots extending from the first gas region through the
assembly to provide fluid communication from the first gas region
into the process region. The plasma baffle assembly further
contains a nose cone extending from an upper surface of the plasma
baffle to a lower surface of the plasma screen. The slots extend
across the upper surface between the nose cone and an outer edge of
the assembly at a tangential angle from a center portion. Each slot
is extended through the plasma baffle assembly at a predetermined
injection angle relative to the substrate receiving surface. The
predetermined injection angle may be within a range from about
20.degree. to about 700, preferably, from about 30.degree. to about
600, and more preferably, from about 40.degree. to about 500, such
as about 45.degree.. Each slot of the plurality of slots may have a
width within a range from about 0.60 mm to about 0.90 mm,
preferably, from about 0.70 mm to about 0.80 mm, such as about 0.76
mm and may have a length within a range from about 10 mm to about
50 mm, preferably, from about 20 mm to about 30 mm, such as about
23 mm or more. The plasma baffle assembly usually contains about 10
slots or more, such as about 20 slots or more. The slots have a
width to prohibit back diffusion of gas or to prohibit formation of
a secondary plasma. In one example, the upper surface of the plasma
baffle is directed downwardly way from the nose cone. The upper
surface may angled in order receive a process gas through openings
of the slots and disperse the process gas with a uniform flow
rate.
[0018] In another example, a plasma baffle assembly for receiving a
process gas within a plasma-enhanced vapor deposition chamber is
provided which includes a plasma baffle plate containing an upper
surface to receive a process gas and a lower surface to emit the
process gas. The plasma baffle assembly contains a plurality of
openings configured to flow the process gas from above the upper
surface to below the lower surface, wherein each opening is
positioned at an obscured angle or at a predetermined angle,
measured from a perpendicular axis of the lower surface.
[0019] In another example, the cooling assembly contains a
plurality of passageways for the second process gas to pass into
the second gas region. The plurality of passageways provides fluid
communication from the plasma screen to the second gas region. The
plurality of passageways contains at least about 10 channels,
preferably, at least about 20 channels, and more preferably, at
least about 30 channels, such as about 36 channels.
[0020] In another example, a showerhead assembly for conducting a
vapor deposition process is provided which includes a showerhead
plate having a bottom surface to substantially cover a substrate
receiving surface within a process chamber, an inner region of the
showerhead plate for distributing a first process gas through a
plurality of slots positioned at a predetermined injection angle
relative to the substrate receiving surface and an outer region of
the showerhead plate for distributing a second process gas through
a plurality of holes.
[0021] In another example, a showerhead assembly for receiving a
process gas within a plasma-enhanced vapor deposition chamber is
provided which includes a showerhead plate containing an upper
surface to receive gases and a lower surface to emit the gases. An
inner area on the upper surface for receiving a first process gas
contains a first plurality of openings configured to flow the first
process gas from above the upper surface to below the lower
surface. An outer area on the upper surface for receiving the
second process gas contains a second plurality of openings
configured to flow the second process gas from above the upper
surface to below the lower surface. For example, a cooling assembly
may be positioned above and in contact with the showerhead plate.
An inner region is formed between the inner area and the cooling
assembly and an outer region is formed between the outer area and
the cooling assembly. The inner region of the showerhead plate may
contain a plasma baffle.
[0022] In another example, a cooling assembly contains a plurality
of passageways for directing a second process gas into the outer
region. Each passageway of the plurality of passageways extends
into the outer region at a predetermined angle. The predetermined
angle may prohibit back diffusion of gas or formation of a
secondary plasma. In one example, the predetermined angle may be
within a range from about 5.degree. to about 850, preferably, from
about 10.degree. to about 45.degree., and more preferably, from
about 15.degree. to about 350. Each passageway of the plurality of
passageways may provide an obscured flow path for the second
process gas into the outer region. In one example, the cooling
assembly may have about 36 passageways.
[0023] In another embodiment, a lid assembly for conducting a vapor
deposition process within a process chamber is provided which
includes an insulation cap and a plasma screen. In one example, the
insulation cap has a centralized channel configured to flow a first
process gas from an upper surface to an expanded channel and an
outer channel configured to flow a second process gas from an upper
surface to a groove which is encircling the expanded channel. In
one example, the plasma screen has an upper surface containing an
inner area with a plurality of holes and an outer area with a
plurality of slots. The insulation cap may be positioned on top of
the plasma screen to form a centralized gas region with the
expanded channel and a circular gas region with the groove.
[0024] In another example, an insulating cap is positioned above
the plasma screen. The insulating cap contains at least two gas
passageways, such that a first gas passageway is positioned to
direct the first process gas to an inner region of the plasma
screen and a second gas passageway is positioned to direct the
second process gas to an outer region of the plasma screen. The
insulating cap contains an electrically insulating material, such
as a ceramic material, a quartz material or a derivative
thereof.
[0025] In another example, a gas manifold is disposed above the
insulating cap and contains at least two gas passageways. A first
gas passageway is positioned to provide the first process gas to
the insulating cap and a second gas passageway is positioned to
provide the second process gas to the insulating cap. A first
conduit and a second conduit may be coupled to the first gas
passageway and are positioned to provide the first process gas a
gas flow in a circular direction. The first conduit and the second
conduit are independently positioned to direct gas at an inner
surface of the first gas passageway. The gas flow usually has the
circular direction with a geometry of a vortex, a helix, a spiral,
a swirl, a twirl, a twist, a coil, a corkscrew, a curl, a
whirlpool, or derivatives thereof. The first conduit and the second
conduit are independently positioned at an angle from a center axis
of the first gas passageway. The angle may be greater than
0.degree., preferably, greater than about 20.degree., and more
preferably, greater than about 35.degree.. A valve may be coupled
between the first conduit and a precursor source to enable an ALD
process with a pulse time of about 10 seconds or less, preferably,
about 6 seconds or less, and more preferably, about 1 second or
less, such as within a range from about 0.01 seconds to about 0.5
seconds.
[0026] In another example, a capping assembly for conducting a
vapor deposition process within a process chamber is provided which
includes an insulation cap containing an upper surface configured
to receive a grounded gas manifold, a first channel configured to
flow a first process gas from the upper surface to a lower surface
of the insulation cap and a second channel configured to flow a
second process gas from the upper surface to the lower surface. The
lower surface may further contain an inner region and an outer
region, such that the first channel is in fluid communication with
the inner region and the second channel is in fluid communication
with the outer region. In one example, the inner region contains an
expanding channel. The expanding channel may have an inner diameter
within a range from about 0.5 cm to about 7 cm, preferably, from
about 0.8 cm to about 4 cm, and more preferably, from about 1 cm to
about 2.5 cm. Also, the expanding channel may contain an outer
diameter within a range from about 2 cm to about 15 cm, preferably,
from about 3.5 cm to about 10 cm, and more preferably, from about 4
cm to about 7 cm.
[0027] In another example, a plasma screen assembly for receiving a
process gas within a plasma-enhanced vapor deposition chamber is
provided which includes a plasma screen containing an upper surface
to receive gases and a lower surface to emit the gases, an inner
area on the upper surface for receiving a first process gas,
wherein the inner area contains a first plurality of openings
configured to flow the first process gas from above the upper
surface to below the lower surface, and an outer area on the upper
surface for receiving the second process gas, wherein the outer
area contains a second plurality of openings configured to flow the
second process gas from above the upper surface to below the lower
surface. The inner area further contains a zone free of the
plurality of openings and a first flow pattern of the first process
gas is directional at a line-of-sight to the zone, so to be
directional obscure to the plurality of openings.
[0028] In another example, the plasma screen assembly contains an
inner area for receiving the first process gas and an outer area
for receiving the second process gas. The inner area of the plasma
screen assembly contains a plurality of holes for directing the
first process gas to the plasma baffle assembly. Each hole may have
a diameter within a range from about 0.5 mm to about 5 mm
preferably, from about 1 mm to about 3 mm, such as about 1.5 mm.
The outer area of the plasma screen contains a plurality of slots
for directing the second process gas into the second gas region.
The slots may be parallel or substantially parallel to a substrate
receiving surface or the slots may be perpendicular or
substantially perpendicular to the plurality of holes within the
first area of the plasma screen. Each slot may have a width within
a range from about 0.20 mm to about 0.80 mm, preferably, from about
0.40 mm to about 0.60 mm, such as about 0.51 mm. The plasma screen
assembly contains at least about 10 slots, preferably about 36
slots or more. Also, the plasma screen assembly is formed from an
electrically insulating material, such as a ceramic material, a
quartz material or a derivative thereof.
[0029] In another example, a plasma screen assembly for receiving a
process gas within a plasma-enhanced vapor deposition chamber is
provided which includes an upper surface to receive gases and a
lower surface to emit the gases. An inner area on the upper surface
for receiving a first process gas contains a first plurality of
openings configured to flow the first process gas from above the
upper surface to below the lower surface. An outer area on the
upper surface for receiving the second process gas contains a
second plurality of openings configured to flow the second process
gas from above the upper surface to below the lower surface.
[0030] Embodiments of the invention also provide a method for
forming a material on a substrate during a thermal ALD process and
a PE-ALD process. In another embodiment, a method is provided which
includes flowing at least one process gas through at least one
conduit to form a circular gas flow pattern, exposing a substrate
to the circular gas flow pattern, sequentially pulsing at least one
chemical precursor into the process gas and igniting a plasma from
the process gas to deposit a material on the substrate. In one
example, the circular gas flow pattern has circular geometry of a
vortex, a helix, a spiral, a swirl, a twirl, a twist, a coil, a
corkscrew, a curl, a whirlpool, or derivatives thereof. Materials
that may be deposited by the method include ruthenium, tantalum,
tantalum nitride, tungsten, or tungsten nitride.
[0031] In another example, a method for depositing a material on a
substrate is provided which includes positioning a substrate on a
substrate support within a process chamber containing a chamber lid
assembly, flowing at least one carrier gas through at least one
conduit to form a circular gas flow pattern, exposing the substrate
to the circular gas flow pattern, pulsing at least one precursor
into the at least one carrier gas and depositing a material
containing at least one element from the at least one precursor
onto the substrate. The chamber lid assembly may contain a
showerhead assembly having an inner region and an outer region, a
plasma screen disposed above the showerhead assembly and configured
to direct a first process gas to the inner region and a second
process gas to the outer area, a first gas region located above the
inner region and between the showerhead assembly and the plasma
screen and a second gas region located above the outer region.
[0032] In another example, a method for depositing a material on a
substrate is provided which includes positioning a substrate on a
substrate support within a process chamber containing a gas
delivery system capable of forming a gas flow in a circular
direction, flowing at least one carrier gas into the process
chamber to form a circular gas flow pattern and exposing the
substrate to the circular gas flow pattern during a plasma-enhanced
atomic layer deposition process comprising sequentially igniting a
plasma and pulsing at least one precursor into the at least one
carrier gas to deposit a material onto the substrate.
[0033] In another example, a method for forming a ruthenium
material on a substrate is provide which includes positioning a
substrate within a plasma-enhanced process chamber containing a
showerhead, a plasma baffle and a plasma screen and exposing the
substrate sequentially to a pyrrolyl ruthenium precursor and a
reagent during an ALD process while forming a ruthenium material on
the substrate. The pyrrolyl ruthenium precursor contains ruthenium
and at least one pyrrolyl ligand with the chemical formula of:
##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are
each independently selected from hydrogen or an organic group, such
as methyl, ethyl, propyl, butyl, amyl, derivatives thereof or
combinations thereof. In one example, each R.sub.2, R.sub.3,
R.sub.4 and R.sub.5 is either a hydrogen group or a methyl group.
In another example, each R.sub.2 and R.sub.5 is a methyl group or
an ethyl group.
[0034] The method further provides that the pyrrolyl ruthenium
precursor may contain a first pyrrolyl ligand and a second pyrrolyl
ligand, such that the first pyrrolyl ligand may be the same as or
different than the second pyrrolyl ligand. Alternatively, the
pyrrolyl ruthenium precursor may contain a first pyrrolyl ligand
and a dienyl ligand. For example, the pyrrolyl ruthenium precursor
may be a pentadienyl pyrrolyl ruthenium precursor, a
cyclopentadienyl pyrrolyl ruthenium precursor, an alkylpentadienyl
pyrrolyl ruthenium precursor or an alkylcyclopentadienyl pyrrolyl
ruthenium precursor. Therefore, the method provides that the
pyrrolyl ruthenium precursor may be an alkyl pyrrolyl ruthenium
precursor, a bis(pyrrolyl) ruthenium precursor, a dienyl pyrrolyl
ruthenium precursor, or derivatives thereof. Some exemplary
pyrrolyl ruthenium precursors include bis(tetramethylpyrrolyl)
ruthenium, bis(2,5-dimethylpyrrolyl) ruthenium,
bis(2,5-diethylpyrrolyl) ruthenium, bis(tetraethylpyrrolyl)
ruthenium, pentadienyl tetramethylpyrrolyl ruthenium, pentadienyl
2,5-dimethylpyrrolyl ruthenium, pentadienyl tetraethylpyrrolyl
ruthenium, pentadienyl 2,5-diethylpyrrolyl ruthenium,
1,3-dimethylpentadienyl pyrrolyl ruthenium, 1,3-diethylpentadienyl
pyrrolyl ruthenium, methylcyclopentadienyl pyrrolyl ruthenium,
ethylcyclopentadienyl pyrrolyl ruthenium, 2-methylpyrrolyl pyrrolyl
ruthenium, 2-ethylpyrrolyl pyrrolyl ruthenium, and derivatives
thereof.
[0035] In another example, a method for forming a ruthenium
material on a substrate is provide which includes positioning a
substrate within a plasma-enhanced process chamber containing a
showerhead, a plasma baffle and a plasma screen and exposing the
substrate sequentially to an active reagent and a pyrrolyl
ruthenium precursor during a PE-ALD process. Although a plasma may
be ignited during any time period of the PE-ALD process,
preferably, the plasma is ignited while the reagent is exposed to
the substrate. The plasma activates the reagent to form an active
reagent. Examples of an active reagent include an ammonia plasma, a
nitrogen plasma and a hydrogen plasma. One embodiment of the PE-ALD
process provides that the plasma is generated external from the
process chamber, such as by a remote plasma generator (RPS) system.
However, a preferred embodiment of the PE-ALD process provides that
the plasma is generated in situ by a plasma capable process chamber
utilizing a radio frequency (RF) generator.
[0036] In another example, a method for forming a ruthenium
material on a substrate is provide which includes positioning a
substrate within a plasma-enhanced process chamber containing a
showerhead, a plasma baffle and a plasma screen and exposing the
substrate sequentially to a reagent and a pyrrolyl ruthenium
precursor during a thermal-ALD process. The ruthenium material may
be deposited on a barrier layer (e.g., copper barrier) or
dielectric material (e.g., low-k) disposed on the substrate during
the various ALD processes described herein. The barrier layer may
contain a material that includes tantalum, tantalum nitride,
tantalum silicon nitride, titanium, titanium nitride, titanium
silicon nitride, tungsten or tungsten nitride. In one example, the
ruthenium material is deposited on a tantalum nitride material
previously formed by an ALD process or a PVD process. The
dielectric material may include silicon dioxide, silicon nitride,
silicon oxynitride, carbon-doped silicon oxides or a
SiO.sub.xC.sub.y material.
[0037] A conductive metal may be deposited on the ruthenium
material. The conductive material may contain copper, tungsten,
aluminum, an alloy thereof or a combination thereof. In one aspect,
the conductive metal may be formed as one layer during a single
deposition process. In another aspect, the conductive metal may be
formed as multiple layers, each deposited by an independent
deposition process. In one embodiment, a seed layer is deposited on
the ruthenium material by an initial deposition process and a bulk
layer is subsequently deposited thereon by another deposition
process. In one example, a copper seed layer is formed by an
electroless deposition process, an electroplating (ECP) process or
a PVD process and a copper bulk layer is formed by an electroless
deposition process, an ECP process or a CVD process. In another
example, a tungsten seed layer is formed by an ALD process or a PVD
process and a tungsten bulk layer is formed by a CVD process or a
PVD process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] So that the manner in which the above recited features of
the invention are attained and can be understood in detail, a more
particular description of the invention, briefly summarized above,
may be had by reference to the embodiments thereof which are
illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only typical embodiments of
this invention and are therefore not to be considered limiting of
its scope, for the invention may admit to other equally effective
embodiments.
[0039] FIGS. 1A-1G illustrate schematic views of a process chamber
as described in an embodiment herein;
[0040] FIGS. 2A-2B illustrate a schematic view of an isolation ring
as described in an embodiment herein;
[0041] FIGS. 3A-3B illustrate schematic views of a showerhead as
described in an embodiment herein;
[0042] FIGS. 4A-4F illustrate schematic views of a water box as
described in an embodiment herein;
[0043] FIGS. 5A-5F illustrate schematic views of plasma baffle
inserts as described in embodiments herein;
[0044] FIGS. 6A-6B illustrate schematic views of a plasma screen
insert as described in an embodiment herein;
[0045] FIGS. 7A-7C illustrate schematic views of an insulation cap
insert as described in an embodiment herein;
[0046] FIGS. 8A-8D illustrate schematic views of a gas manifold
assembly as described in an embodiment herein;
[0047] FIGS. 9A-9D illustrate schematic views of a gas flows
described in an embodiment herein; and
[0048] FIGS. 10A-10C illustrate alternative schematic views of a
gas flows as described in an embodiment herein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0049] Embodiments of the invention provide an apparatus configured
to deposit a material during a thermal atomic layer deposition
(ALD) process, or preferably, during a plasma-enhance ALD (PE-ALD)
process. Other embodiments of the invention provide processes for
forming the material within the process chamber. In one embodiment,
a process chamber is configured to perform a PE-ALD process and has
multiple components that are electrically insulated, electrically
grounded or RF hot. In one example, a chamber body and gas manifold
assembly are grounded and separated by electrically insulated
components, such as an isolation ring, a plasma screen insert and
an insulation cap. A showerhead, a plasma baffle and a water box
are disposed between the electrically insulated components and are
RF hot when activated by a plasma generator.
Hardware
[0050] FIGS. 1A-1G illustrate schematic views of lid assembly 100
that may be used to perform a variety of ALD processes. In one
embodiment, process chamber 50 may be used to form materials on
substrate 8 during a thermal ALD process or a PE-ALD process. FIG.
1A depicts a schematic cross-sectional view of process chamber 50
that may be used to perform integrated circuit fabrication. Process
chamber 50 contains lid assembly 100 attached to chamber body
assembly 90. Process region 60 for substrate processing is formed
and generally situated between lid assembly 100 and chamber body
assembly 90, and more specifically, just above support surface 41
of substrate support 40 and substrate 8 and just below upper
surface 62. In one embodiment, the chamber spacing between upper
surface 62 and support surface 41 is within a range from about 0.50
mm to about 50.00 mm, preferably, from about 1.00 mm to about 12.00
mm, and more preferably, from about 4.00 mm to about 8.00 mm, such
as 5.84 mm (0.230 in). The spacing may vary depending on the gases
being delivered and the process conditions during a deposition
process.
[0051] Substrate support 40 contains edge ring 44 and heating
element 45 (FIGS. 1A and 1G). Heating element 45 is embedded within
substrate support 40. Edge ring 44 is circumferentially disposed
around substrate support 40 and over an upper portion of substrate
support 40. Inner edge rings 48a, 48b and 48c are situated on
heating element 45 and below the segment of edge ring 44 which
covers the upper portion of substrate support 40. Edge ring 44 may
be used as a purge ring by allowing an edge purge gas to flow from
substrate support 40, through gap 47, between inner edge rings 48a,
48b and 48c, edge ring 44 and heating element 45 and over the edge
of substrate 8 (FIG. 1G). The flow of the edge purge gas prevents
reactive process gasses from diffusing into heating element 45.
[0052] Choke gap 61 is a circumferential gap or space formed
between edge ring 44 and upper surface 62, more specifically,
between the top edge surface of edge ring 44 and lower surface 202d
of isolation ring 200. Choke gap 61 also helps provide a more
uniform pressure distribution within process region 60 by partially
separating process region 60 from the non-uniform pressure
distribution of interior chamber region 59. Choke gap 61 may be
varied depending on the process conditions and the required pumping
efficiency. The pumping efficiency during a deposition process may
be controlled by adjusting choke gap 61. Choke gap 61 is increased
by lowering substrate support 40 or decreased by raising substrate
support 40. The pumping conductance from the pumping port 38 in the
lower portion of process chamber 50 to the center of channel 820 is
modified by changing the distance of choke gap 61 to control the
thickness and the uniformity of a film during deposition processes
described herein. In one embodiment, the spacing of upper choke gap
61 is within a range from about 0.50 mm to about 50.00 mm,
preferably, from about 1.00 mm to about 5.00 mm, and more
preferably, from about 2.5 mm to about 4 mm, such as 3.30 mm (0.130
in).
[0053] In one embodiment, the pressure differentials of the pumping
conductance may be controlled in order to reduce or eliminate the
formation of secondary plasmas. Since the generation and
sustainability of a plasma is ion concentration dependant, the
pressure within a particular region may be reduced to minimize the
ion concentration. Therefore, a secondary plasma may be avoided
within a desired region of the process chamber. In a preferred
embodiment, process chamber 50 is configured to conduct a PE-ALD
process. Therefore, various regions and components throughout
process chamber 50 are electrically insulated, electrically
grounded or RF hot. In one example, chamber body 80 and gas
manifold assembly 800 are grounded and separated by electrically
insulated isolation ring 200, plasma screen insert 600 and
insulation cap 700. Therebetween the electrically insulated
components, showerhead 300, plasma baffle insert 500 and water box
400 are RF hot when activated upon by plasma generator system 92
(FIG. 1E). Process chamber 50 also contains insulator ring liner
82, chamber liner 84 and other insulation liners to minimize or
completely eliminate any line-of-sight between upper surface 62 and
the various surfaces of chamber body assembly 90. The insulation
liners help minimize or eliminate plasma erosion of the metallic
surfaces of chamber body assembly 90. Therefore, substrate support
40 and a wafer contained thereon are a grounded path from RF
powered showerhead 300 while generating a plasma.
[0054] Referring to FIG. 1A, in one aspect, since process region 60
is isolated from interior chamber region 59, a reactant gas or
purge gas needs only adequately fill process region 60 to ensure
sufficient exposure of substrate 8 to the reactant gas or purge
gas. In a conventional chemical vapor deposition process, process
chambers are required to provide a combined flow of reactants
simultaneously and uniformly to the entire substrate surface in
order to ensure that the co-reaction of the reactants occurs
uniformly across the surface of substrate 8. During an ALD process,
process chamber 50 is used to sequentially expose substrate 8 to
chemical reactants, such as a gas or a plasma, that adsorb or react
as thin layers onto the surface of substrate 8. As a consequence,
an ALD process does not require a flow of a reactant to
simultaneously reach the surface of substrate 8. Instead, a flow of
a reactant needs to be provided in an amount which is sufficient to
adsorb a thin layer of the reactant on the surface of substrate 8
or in an amount which is sufficient to react with an adsorbed layer
on the surface of substrate 8.
[0055] Since process region 60 may comprise a smaller volume when
compared to the inner volume of a conventional CVD chamber, a
smaller amount of gas is required to fill process region 60 for a
particular process in an ALD sequence. Since interior chamber
region may have a volume of about 20 L, process region 60 is
separated from interior chamber region 59 to have a smaller volume,
such as about 3 L or less, preferably, about 2 L or less, and more
preferably, about 1 L or less. In an embodiment for a chamber
adapted to process 200 mm diameter substrates, the volume of
process region 60 is about 1,000 cm.sup.3 or less, preferably,
about 500 cm.sup.3 or less, and more preferably, about 200 cm.sup.3
or less. In an embodiment for a chamber adapted to process 300 mm
diameter substrates, the volume of process region 60 is about 3,000
cm.sup.3 or less, preferably, about 1,500 cm.sup.3 or less, and
more preferably, about 1,000 or less, such as about 800 cm.sup.3 or
less. In one example of a chamber adapted to process 300 mm
diameter substrates, process region 60 has a volume of about 770
cm.sup.3 or less. In another embodiment, substrate support 40 may
be raised or lowered to adjust the volume of process region 60. For
example, substrate support 40 may be raised to form process region
60 having a volume of about 770 cm.sup.3 or less. The smaller
volume of process region 60 requires less gas (e.g., process gas,
carrier gas or purge gas) to be flowed into process chamber 50
during a process. Therefore, the throughput of process chamber 50
is greater since less time is needed to provide and remove gases
and the operation cost is reduced since the waste of chemical
precursors and other gases may be minimized due to the smaller
amount of the gases.
[0056] FIG. 1B further illustrates an exploded view of lid assembly
100 and components thereof. Lid support 103 having lower surface
102 and upper surface 104 may be formed from a variety of materials
including a metal. Preferably, lid support 103 is formed from a
metal, such as aluminum, steel, stainless steel (e.g.,
iron-chromium alloys optionally containing nickel), iron, nickel,
chromium, an alloy thereof or combinations thereof. Lid assembly
100 may be attached to chamber body assembly 90 by hinges (not
shown). Alignment slots 101 on lid support 103 are positioned to be
aligned with a post (not shown) attached to chamber body assembly
90, once lid assembly is in a closed position. Lid support 103 also
contains support bracket 110 and handle assembly 107 mounted on
upper surface 104. Handle assembly 107 may contain thermal isolator
108 between handle 106 positioned on upper surface 104. Also, lid
assembly 100 has opening 120 with ledge surface 122 and wall
surface 124. Multiple holes and openings, such as ports 116, 117
and 118, may also pass through lid support 103 and may provide a
passageway for conduit, tubing, hosing, fasteners, instruments and
other devices. Lid support 103 further contains holes that may not
pass through. For example, holes 119 may be threaded and used to
receive a fastener, such as a screw or a bolt.
[0057] Lid assembly 100 further contains isolation ring 200,
showerhead 300, water box 400, plasma baffle insert 500, plasma
screen insert 600, insulation cap 700 and gas manifold assembly
800. Each component (i.e., isolation ring 200, showerhead 300,
water box 400, plasma baffle insert 500, plasma screen insert 600,
insulation cap 700 or gas manifold assembly 800) of lid assembly
100 may be scaled to process a substrate of varying size, such as a
wafer with a 150 mm diameter, a 200 mm diameter, a 300 mm diameter
or larger. Also, each component may be positioned and secured on
lid support 103 by clips 780. Clip 780 latches over upper surface
404 of water box 400 and is secured by a fastener placed through
holes 119 (FIGS. 1A-1G). In one example, clip 780 contains metal
clip segment 784 disposed on insulator segment 782. Insulator
segment 782 may be formed from an electrically insulating material,
a thermally insulating material or a combination thereof. Insulator
segments 782 provide electrical and thermal isolation between upper
surface 404 and lid support 103 while clips 780 secure the various
components of lid assembly 100. Axis 10 pass through the center of
lid assembly 100 including, once aligned, opening 120 of lid
support 103 and opening 220 of isolation ring 200, opening 320 of
showerhead 300, opening 420 of water box 400, conical nose 520 of
plasma baffle insert 500, center portion 601 of plasma screen
insert 600, channel 720 of insulation cap 700 and channel 820 of
gas manifold assembly 800.
[0058] FIG. 1C depicts a view from underneath lid assembly 100,
down axis 10, to illustrate upper surface 62 and lower surface 102
of lid support 103. Upper surface 62 of process region 60 is formed
collectively of lower surfaces 202d and 205d of isolation ring 200,
lower surface 302c of showerhead 300 and lower surface 502 of
plasma baffle insert 500. Substrate 8 is positioned below upper
surface 62 within process region 60 and exposed to process gases
during a deposition process. In one embodiment, the substrate is
sequentially exposed to at least two process gases (e.g., gas or
plasma) during an ALD process. In one example of an ALD process,
substrate 8 is exposed to a first process gas coming from slots 510
of plasma baffle insert 500 and to a second process gas coming from
holes 310 of showerhead 300.
[0059] A view along axis 10 further illustrates that although
opening 508 of slot 510 is visible on lower surface 502, the other
end of slot 510 (e.g., opening 506 on upper surface 503, FIG. 5C)
is not visible. This obscured view down axis 10 is due to the angle
of slots 510 (angle .alpha..sub.1 in FIG. 5B) that depict a pathway
between process region 60 and gas region 640 above plasma baffle
insert 500 does not have a line-of-sight. The obscured pathway has
many advantages over a non-obscured pathway having a line-of-sight
between process region 60 and gas region 640 including a reduction
or absence of a secondary plasma within or above plasma baffle
insert 500.
[0060] "Line-of-sight" as used herein refers to a straight path or
a substantially straight path between two points. The straight path
or the substantially straight path may provide an unobstructed
pathway or an unobscured pathway for a gas or a plasma to flow
between at least two points. Generally, an obstructed pathway or an
obscured pathway prohibits or substantially reduces the passage of
a plasma while permitting the passage of a gas. Therefore, a
line-of-sight pathway usually permits the passage of a gas or a
plasma, while a pathway not have a line of sight between two points
prohibits or substantially reduces the passage of a plasma and
permits the passage of a gas.
[0061] In one embodiment, a portion of upper surface 62, namely
lower surface 302c and lower surface 502, may be roughened (e.g.,
machined) to produce more surface area across upper surface 62. The
increased surface area of upper surface 62 may increase adhesion of
accumulated material during a deposition process, while decreasing
contaminants due to the flaking of the accumulated material. In one
example, the mean roughness (R.sub.a) of each lower surface 302c
and lower surface 502 independently may be at least about 15
microinch (about 0.38 .mu.m), preferably, about 100 microinch
(about 2.54 .mu.m), and more preferably, about 200 microinch (about
5.08 .mu.m) or higher. Lower surface 102 of lid support 103 may
also be roughened to have a roughness of at least about 15
microinch (about 0.38 .mu.m), preferably, at least about 50
microinch (about 1.27 .mu.m), for example, about 54 microinch
(about 1.37 .mu.m).
[0062] FIGS. 1B and 1D further illustrates gas manifold assembly
800 containing conduit assembly 840, manifold cap assembly 850 and
gas conduit assembly 830. Manifold cap assembly 850 may have
viewing window assembly 826 for observing ignited plasma (FIG. 1A).
Alternatively, manifold cap assembly 850 may contain surface 825
which lacks a viewing window (FIG. 1D). Gas conduit assembly 830
may be connected to and in fluid communication with port 117 at
flange 834 while extended to be connected to and in fluid
communication with gas inlet 813 on manifold block 806 (FIGS. 1D
and 8D).
[0063] In one embodiment, plasma generator system 92 is attached to
lid assembly 100 by RF strap 88 (FIG. 1D). A portion of plasma
generator system 92, namely RF stinger 94 and insulator 95a,
protrudes through port 116 on lid support 103 and couples to
showerhead 300 and water box 400. Insulator 95a maintains RF
stinger 94 electrically isolated from lid support 103 while RF
strap electrically connects RF stinger 94 to region 950 containing
contacts 350 and 450 on showerhead 300 and water box 400. RF
stinger 94 is a conductive material, such as a metal rod or
electrode, which may contain copper, brass, stainless steel, steel,
aluminum, iron, nickel, chromium, alloys thereof, other conductive
materials or combinations thereof.
[0064] Plasma generator system 92 further contains plasma generator
97 that may be mounted under chamber body 80 (FIG. 1E). Insulator
95b may be placed between plasma generator 97 and chamber body 80
to electrically isolate plasma generator 97. Match 96 may protrude
through insulator 95b and be in electrical contact with chamber
body 80. Plasma generator 97 further contains connector 98. In one
example, connector 98 is an RF coaxial cable connector, such as a
type N connector. Plasma generator system 92 may be operated by
plasma generator controller 22 connected to signal bus system 30.
In one example, process conditions of plasma generator system 92
may be set to have a chamber impendence of about 4 ohms with about
9 amperes at about 300 watts. A plasma system and a process chamber
that may be used in combination with lid assembly 100 or may be
used as plasma generator system 92 and chamber body assembly 90 is
the TXZ.RTM. CVD, chamber available from Applied Materials, Inc.,
located in Santa Clara, Calif. Further disclosure of plasma systems
and process chambers is described in commonly assigned U.S. Pat.
Nos. 5,846,332, 6,079,356, and 6,106,625, which are incorporated
herein by reference in their entirety, to provide further
disclosure for a plasma generator, a plasma chamber, a vapor
deposition chamber, a substrate pedestal and chamber liners.
[0065] Chamber body assembly 90 of process chamber 50 contains
insulator ring liner 82 that is used to reduce plasma exposure to
chamber body 80 and helps ensure that plasma is confined within
process region 60 (FIG. 1F). Also, chamber body assembly 90
generally houses substrate support 40 attached to post 42 within
interior chamber region 59. Substrate support 40 is movable in a
vertical direction inside process chamber 50 using support
controller 20. In one embodiment, substrate support 40 is
rotatable. Process region 60 is situated above substrate support 40
and below lid assembly 100, preferably, at least below showerhead
300, plasma baffle insert 500 and a portion of isolation ring
200.
[0066] Depending on the specific process, substrate 8 may be heated
to some desired temperature prior to or during a pretreatment step,
a deposition step, post-treatment step or other process step used
during the fabrication process. For example, substrate support 40
may be heated using embedded heating element 45. Substrate support
40 may be resistively heated by applying an electric current from
AC power supply to heating element 45. Substrate 8 is, in turn,
heated by substrate support 40. Alternatively, substrate support 40
may be heated using radiant heaters such as, for example, lamps
(not shown).
[0067] Temperature sensor 46, such as a thermocouple, is also
embedded in substrate support 40 to monitor the temperature of
substrate support 40 in a conventional manner. The measured
temperature is used in a feedback loop to control AC power supply
for heating element 45, such that the temperature of substrate 8
may be maintained or controlled at a desired temperature which is
suitable for the particular process application. Substrate lift
pins (not shown) may also be embedded in substrate support 40 and
are used to raise substrate 8 from support surface 41.
[0068] Vacuum pumping system 36 is used to evacuate and to maintain
the pressure inside process chamber 50 (FIG. 1F). Vacuum pumping
system 36 may be connected to process chamber 50 by pumping port 38
and valve 37. Gas manifold assembly 800, through which process
gases are introduced into process chamber 50, is located above
substrate support 40. Gas manifold assembly 800 may be connected to
a gas panel, which controls and supplies various process gases to
process chamber 50.
[0069] Gas sources 70a, 70b, 70c, 70d, and 70e provide precursor
gas, carrier gas or purge gas to process chamber 50 through conduit
system 34. Gas sources 70a, 70b, 70c, 70d and 70e may be directly
or indirectly connected to a chemical supply or a gas supply. The
chemical or gas supplies include a tank, an ampoule, a bubbler, a
vaporizer or another container used to store, transfer or form a
chemical precursor. The chemical or gas supply may also be from an
in-house source. Proper control and regulation of the gas flows
from gas sources 70a, 70b, 70c, 70d, and 70e to gas manifold
assembly 800 are performed by valve assemblies 72a, 72b, 72c, 72d
and 72e coupled to control unit 51. Gas manifold assembly 800
allows process gases to be introduced into process chamber 50 and
may optionally be heated to prevent condensation of any gases
within the conduits or lines of gas manifold assembly 800.
[0070] Each valve assembly 72a, 72b, 72c, 72d and 72e may comprise
a diaphragm and a valve seat. The diaphragm may be biased open or
closed and may be actuated closed or open respectively. The
diaphragms may be pneumatically actuated or may be electrically
actuated. Examples of pneumatically actuated valves are available
from Fujikin and Veriflow and examples of electrically actuated
valves are available from Fujikin. Control unit 51 may be coupled
to valve assemblies 72a, 72b, 72c, 72d and 72e to control actuation
of the diaphragms of the valves. Pneumatically actuated valves may
provide pulses of gases in time periods as low as about 0.020
seconds. Electrically actuated valves may provide pulses of gases
in time periods as low as about 0.005 seconds. Generally
pneumatically and electrically actuated valves may provide pulses
of gases in time periods as high as about 3 seconds. Although
higher time period for gas pulsing is possible, a typical ALD
process utilizes ALD valves to generate pulses of gas while being
opened for an interval of about 5 seconds or less, preferably about
3 seconds or less, and more preferably about 2 seconds or less. In
one embodiment, an ALD valve pulses for an interval in a range from
about 0.005 seconds to about 3 seconds, preferably from about 0.02
seconds to about 2 seconds and more preferably from about 0.05
seconds to about 1 second. An electrically actuated valve typically
requires the use of a driver coupled between the valve and control
unit 51. In another embodiment, each valve assemblies 72a, 72b,
72c, 72d and 72e may contain a mass flow controller (MFC) to
control gas dispersion, gas flow rates and other attributes to an
ALD pulse sequence.
[0071] A precursor or a gas delivery system within an ALD apparatus
is used to store and dispense chemical precursors, carrier gases,
purge gases or combinations thereof. The delivery system may
contain valves (e.g., ALD valves or MFCs), conduits, reservoirs,
ampoules and bubblers, heater and/or control unit systems, which
may be used with process chamber 50 or lid assembly 100 and coupled
in fluid communication with gas manifold 800 or conduit system 34.
In one example, a delivery system may contain gas sources 70a-70e
and valve assemblies 72a, 72b, 72c, 72d, and 72e coupled to control
unit 51. Delivery systems configured for an ALD process system are
described in commonly assigned and co-pending U.S. Ser. No.
11/127,753, entitled "Apparatus and Methods for Atomic Layer
Deposition of Hafnium-Containing High-k Materials," filed May 12,
2005, and published as US 2005-0271812, U.S. Ser. No. 11/119,388,
entitled "Control of Gas Flow and Delivery to Suppress the
Formation of Particle in an MOCVD/ALD System," filed Apr. 29, 2005,
and published as US 2005-0252449, U.S. Ser. No. 10/281,079,
entitled "Gas Delivery Apparatus for Atomic Layer Deposition,"
filed Oct. 25, 2002 and published as US 2003-0121608, and U.S. Ser.
No. 10/700,328, entitled "Precursor Delivery System with Rate
Control," filed Nov. 3, 2003 and published as US 2005-009859, which
are incorporated herein by reference in their entirety.
[0072] Control unit 51, such as a programmed personal computer,
work station computer, or the like, may be coupled to process
chamber 50 to control processing conditions. For example, control
unit 51 may be configured to control flow of various process gases
and purge gases from gas sources 70a-70e through valve assemblies
72a-72e during different stages of a substrate process sequence.
Illustratively, control unit 51 comprises central processing unit
(CPU) 52, support circuitry 54, and memory 56 containing associated
control software 58.
[0073] Software routines, as required, may be stored in memory 56
or executed by a remotely located source (e.g., computer or
server). The software routines are executed to initiate process
recipes or sequences. The software routines, when executed,
transform the general purpose computer into a specific process
computer that controls the chamber operation during a chamber
process. For example, software routines may be used to precisely
control the activation of gas sources 70a-70e through valve
assemblies 72a-72e during the execution of process sequences
according to the embodiments described herein. Alternatively, the
software routines may be performed in the hardware, as an
application specific integrated circuit or other type of hardware
implementation or a combination of software or hardware.
[0074] Control unit 51 may be one of any form of general purpose
computer processor that can be used in an industrial setting for
controlling various chambers and sub-processors. CPU 52 may use any
suitable memory 56, such as random access memory, read only memory,
floppy disk drive, compact disc drive, hard disk or any other form
of digital storage, local or remote. Various support circuits may
be coupled to the CPU 52 for supporting process chamber 50. Control
unit 51 may be coupled to another controller that is located
adjacent individual chamber components, such as programmable logic
controllers of valve assemblies 72a-72e. Bi-directional
communications between control unit 51 and various other components
of process chamber 50 are handled through numerous signal cables
collectively referred to as signal buses 30, some of which are
illustrated in FIG. 1F. In addition to control of process gases and
purge gases from gas sources 70a-70e, valve assemblies 72a-72e and
any programmable logic controllers, control unit 51 may be
configured to be responsible for automated control of other
activities used during a fabrication process. Control unit 51 is
connected to plasma generator controller 22, vacuum pumping system
36 and support controller, including temperature monitoring and
control and control of lift pins (not shown).
[0075] Isolation ring 200 contains opening 220 (FIGS. 2A-2B) and
may be positioned between showerhead 300 and lid support 103 (FIGS.
1A-1B). Isolation ring 200 contains upper surface 204 to support
showerhead 300. Opening 220 may be aligned with opening 120 such
that axis 10 passes through each center. Isolation ring contains
inner surfaces 205a, 205b, 205c and 205d that taper inward towards
axis 10.
[0076] Isolation ring 200 further contains lower surfaces 202a,
202b, 202c and 202d. Lower surface 202a may be used to contact
ledge surface 122 of lid support 103 while supporting isolation
ring 200. Lower surfaces 202d and 205d forms process region 60
while contributing to upper surface 62 therein (FIG. 1C). The
portion of upper surface 62 contributed by lower surface 202d forms
an outer ring seal between process region 60 and interior chamber
region 59. Isolation ring 200 may be formed from an electrically
insulating material that is plasma resistant or chemical resistant
against the process reagents. Isolation ring 200 may also contain a
thermally insulating material. Materials useful to construct
isolation ring 200 include ceramic, quartz, fused quartz, sapphire,
pyrolytic boron nitrite (PBN) material, glass, plastic, derivatives
thereof, or combinations thereof.
[0077] Showerhead 300 contains opening 320 (FIGS. 3A-3B) and may be
positioned between isolation ring 200 and water box 400 (FIG.
1A-1B). Showerhead 300 contains upper surfaces 303, 304, and 306,
where upper surfaces 304 and 306 may be used to support water box
400. Wall surfaces 305a and 305b are disposed between upper
surfaces 303, 304 and 306. Showerhead 300 further contains lower
surfaces 302a, 302b, and 302c. Lower surface 302a may be used to
contact upper surface 204 of isolation ring 200 while supporting
showerhead 300. Lower surface 302c also forms process region 60
while contributing to upper surface 62 therein (FIG. 1C).
Showerhead 300 may be formed from a variety of materials including
a metal or another electrically conductive material. Preferably,
showerhead 300 is formed from a metal, such as aluminum, steel,
stainless steel, iron, nickel, chromium, an alloy thereof or
combinations thereof.
[0078] Opening 320 passes through showerhead 300 and may be aligned
with openings 120 and 220 such that axis 10 passes through each
center (FIG. 1B). Also, opening 320 passes through ring assembly
330. Ring assembly 330 is positioned in the center of showerhead
300 and may be used to house plasma baffle insert 500. Ring
assembly 330 contains ring 328 disposed above the surface of upper
surface 303. Ledge 332 protrudes inwardly from ring 328 towards
axis 10 and is used to support plasma baffle insert 500 thereon.
Ledge 322 protrudes outwardly from ring 328 away from axis 10 and
is used to support water box 400 in conjunction with upper surfaces
304 and 306. Upper surface 324 of ring 328 is used to support
plasma screen insert 600.
[0079] Upper surface 303 of showerhead 300 receives a process gas
for distributing into process region 60 through holes 310. Holes
310 pass through showerhead 300 from upper surface 303 to lower
surface 302c and provide fluid communication therethrough. Holes
310 in showerhead 300 may have a diameter within a range from about
0.10 mm to about 1.00 mm, preferably, from about 0.20 mm to about
0.80 mm, and more preferably, from about 0.40 mm to about 0.60 mm.
Showerhead 300 may have at least about 100 holes, preferably, about
1,000 holes, and more preferably, about 1,500 holes or more.
Showerhead 300 may have as many as 6,000 holes or 10,000 holes
depending on size of the holes 310, the distribution pattern of the
holes 310, size of substrate and desired exposure rate. Holes 310
may have a varying or consistent geometry from hole to hole. In one
example, showerhead 300 is constructed from metal (e.g., aluminum
or stainless steel) and has 1,500 holes that are formed with a
diameter of 0.50 mm.
[0080] Showerhead 300 contains opening 320 (FIG. 3) and may be
positioned between isolation ring 200 and water box 400 (FIG.
1A-1B). Showerhead 300 contains upper surfaces 303, 304 and 306,
where upper surfaces 304 and 306 may be used to support water box
400. Wall surfaces 305a and 305b are disposed between upper
surfaces 303, 304 and 306. Showerhead 300 further contains lower
surfaces 302a, 302b and 302c. Lower surface 302a may be used to
contact upper surface 204 of isolation ring 200 while supporting
showerhead 300. Lower surface 302c also forms process region 60
while contributing upper surface 62 therein (FIG. 1C). Showerhead
300 may be formed from a variety of materials including a metal or
another electrically conductive material. Preferably, showerhead
300 is formed from a metal, such as aluminum, steel, stainless
steel, iron, nickel, chromium, alloys thereof or combinations
thereof.
[0081] A plurality of holes 310 are formed through showerhead 300,
so that upper surface 303 is in fluid communication to lower
surface 302c. Holes 310 may have a variety of sizes and be
contained across upper surface 303 and lower surface 302c in
multiple patterns. Each hole of the plurality of holes 310 may have
a diameter within a range from about 0.10 mm to about 1.00 mm,
preferably, from about 0.20 mm to about 0.80 mm, and more
preferably, from about 0.40 mm to about 0.60 mm, such as about 0.51
mm (0.020 in). Showerhead 300 has at least about 100 holes,
preferably, about 1,000 holes, and more preferably, about 1,500
holes or more. For example, showerhead 300 may have as many as
6,000 holes or 10,000 holes depending on size of holes 310, the
pattern of the holes, size of substrate and desired exposure rate.
Preferably, showerhead 300 is constructed from a metal (e.g.,
aluminum or stainless steel) and has 1,500 holes that are formed
with a diameter of about 0.50 mm.
[0082] Water box 400, containing opening 420 (FIGS. 4A-4B), may be
positioned on top of showerhead 300 and used to regulate the
temperature by removing heat from lid assembly 100 (FIG. 1A-1B).
Opening 420 contains ledge surfaces 414a and 414b and inner
surfaces 416a, 416b and 416c. A plurality of passageways 440 radial
extend from inner surface 416b inwardly through water box 400 to
lower surface 402c. Opening 420 is adapted to receive plasma baffle
insert 500, plasma screen insert 600, insulation cap 700.
Insulation cap 700 may be positioned on ledge surface 414a. Water
box 400 may be formed from a variety of materials including a
metal. Preferably, water box 400 is formed from aluminum, steel,
stainless steel, iron, nickel, chromium, an alloy thereof, another
metal, or combinations thereof. Lower surfaces 402a and 402b of
water box 400 rests on upper surfaces 304 and 306 of showerhead
300. Water box 400 also contains upper surface 403 surrounded by
inner surface 405 which has upper surface 404. Water box 400 helps
remove heat from lid assembly 100, especially from showerhead 300.
Upper surface 403 contains inlet 410 and outlet 412 that are in
fluid communication with passageway 430. During a deposition
process, a fluid at an initial temperature is administered into
water box 400 through inlet 410. The fluid absorbs heat while
traveling along passageway 430. The fluid at a higher temperature
is removed from water box 400 through outlet 412.
[0083] The fluid may be in liquid, gas or supercritical state and
is capable of adsorbing and dissipating heat in a timely manner.
Liquids that may be used in water box 400 include water, oil,
alcohols, glycols, glycol ethers, other organic solvents,
supercritical fluids (e.g., CO.sub.2) derivatives thereof or
mixtures thereof. Gases may include nitrogen, argon, air,
hydrofluorocarbons (HFCs), or combinations thereof. Preferably,
water box 400 is supplied with water or a water/alcohol
mixture.
[0084] Inlet 410 may be adapted to receive nozzle 411 connected to
line 425 (e.g., hose) in fluid communication with a fluid source.
Similarly, outlet 412 may be adapted to receive nozzle 413
connected to line 427 in fluid communication with a fluid return.
The fluid source and fluid return may be an in-house cooling system
or an independent cooling system. Lines 425 and 427 are connected
to source nozzle 421 and return nozzle 423 held in positioned on
lid support 103 by support bracket 110. Lines 425 and 427 may be a
tube, a hose, a conduit or a line.
[0085] In one embodiment, the fluid may be administered into water
box 400 at a temperature within a range from about -20.degree. C.
to about 40.degree. C., preferably, from about 0.degree. C. to
about 20.degree. C. The temperature, flow rate, and fluid
composition may be adjusted accordingly to remove the appropriate
amount of heat from lid assembly 100 including showerhead 300 while
maintaining water box 400 at a predetermined temperature. Water box
400 may be maintained at a predetermined temperature within a range
from about 0.degree. C. to about 100.degree. C., preferably, from
about 18.degree. C. to about 65.degree. C., and more preferably,
from about 20.degree. C. to about 50.degree. C.
[0086] In an alternative embodiment, FIGS. 4C-4F illustrate
passageways 430c, 430d, 430e and 430f to provide several different
geometries that may be used to replace passageway 430. Passageways
430c-430f may include a partial loop 432c (FIG. 4C), a single loop
432d (FIG. 4D), multiple loops 432e (FIG. 4E) or contain branches
or spurs 432f around opening 420 (FIG. 4F).
[0087] Gas region 540 is above upper surface 303 of showerhead 300
and below the lower surface 402c of water box 400. Passageways 440
extend from inner surface 416b, pass through water box 400 and into
gas region 540. Inner surface 416b may be inwardly concaved such to
form gas region 441 that is situated between inner surface 416b and
plasma screen insert 600 and insulation cap 700 (FIG. 7C). Gas
region 441 encompasses plasma screen insert 600 to maintain fluid
communication with slots 614. Passageways 440 provide fluid
communication between gas regions 441 and 540. Water box 400
contains numerous passageways 440. For example, water box 400 may
contain at least about 10 passageways, preferably, at least about
24 passageways, and more preferably, at least about 36 passageways
or more.
[0088] FIGS. 5A-5F illustrate schematic views of plasma baffle
insert 500 that may be included as a portion of lid assembly 100 as
described in several embodiments. Plasma baffle insert 500 is
configured to receive a process gas from gas region 640 and
distribute or inject the process gas into process region 60.
Preferably, plasma baffle insert 500 is configured to distribute
the process gas at a predetermined angle. Upper surface 503
contains slots 510 extending through plasma baffle insert 500 to
lower surface 502 for distributing the process gas into process
region 60.
[0089] Plasma baffle insert 500 is illustrated containing conical
nose 520 extending from upper surface 503 to nose surface 522 (FIG.
5A). Nose surface 522 may have a variety of geometries, such as
flat (FIG. 5B) or conical nose 520 may extend to a point (not
illustrated). Preferably, nose surface 522 is substantially,
horizontally flat for contacting plasma screen insert 600. Conical
nose 520 may extend into gas region 640, which is a region formed
above plasma baffle insert 500, below plasma screen insert 600 and
within ring assembly 330. Conical nose 520 occupies a predetermined
volume within gas region 640. A less amount of process gas is
required to fill gas region 640 during a deposition process if
conical nose 520 occupies a larger volume. Therefore, a quicker ALD
cycle is realized since a reduced amount of process gas is more
quickly administered and removed from gas region 640 during each
half cycle of an ALD process.
[0090] Plasma baffle insert 500 contains lower rim 512 having lower
surface 502 and upper rim 514 having upper surface 505 and lower
surface 504. Lower rim 512 and upper rim 514 are separated by gap
513. A gasket may be placed within gap 513 to provide more
conductivity or a better seal. A gasket may include an o-ring or
sealant. Preferably, the gasket is a RF gasket and contains a
conductive material, such as a metal cable or a conductively
doped-polymeric material. In a preferred example, a RF gasket, such
as a twisted stainless steel cable, is placed along gap 513 to
provide a more conductive contact with showerhead 300. Plasma
baffle insert 500 may be positioned within opening 320 of
showerhead 300 so that lower surface 504 of upper rim 514 rests on
ledge 332 of showerhead 300 (FIG. 1A-1B). Plasma baffle insert 500
is also circumferentially surrounded by ring assembly 330 within
opening 320. Plasma baffle insert 500 may be formed from aluminum,
steel, stainless steel, iron, nickel, chromium, other metals,
alloys thereof or combinations thereof.
[0091] Plasma baffle insert 500 contains a plurality of slots 510,
such that openings 508 of upper surface 503 is in fluid
communication to openings 506 of lower surface 502 (FIGS. 5B and
5C). Slots 510 provide access for a process gas to flow from gas
region 640 and into process region 60 at a predetermined angle.
Ideally, slots 510 direct the process gas to contact substrate 8 or
support surface 41 at an injection angle .alpha..sub.1 measured
between axis 10 and line 532. Axis 10 extends perpendicular through
lower surface 502 while line 532 extends along the plane of slots
510. Therefore, slots 510 contained within plasma baffle insert 500
are positioned at injection angle .alpha..sub.1 to direct a process
gas having a flow pattern at injection angle .alpha..sub.1, as
depicted in FIGS. 5C and 9C-9D.
[0092] In some embodiments, plasma baffle insert 500 may contain
trough 501 or a plurality of holes 530 to assist in moving process
gases from upper surface 503. In one embodiment, plasma baffle
insert 500 may contain trough 501 around an outside perimeter of
slots 510, as depicted in FIGS. 5A-5C. Alternatively, slots 510 may
extend into trough 501 (not shown).
[0093] In another embodiment, plasma baffle insert 500 may contain
holes 530 around an outside perimeter of conical nose 520, as
depicted in FIGS. 5D-5F. Each hole 530 extends from upper surface
503 to lower surface 502 along axial line 538. In one example, each
hole 530 has a constant diameter along axis line 538. Preferably,
each hole 530 contains upper passageway 526a and lower passageway
526b separated by choke 528. The diameter of upper passageway 526a
is usually larger than the diameter of lower passageway 526b.
[0094] In some embodiments, a process gas with a flow pattern
parallel or perpendicular to support surface 41 (i.e., about
0.degree. or about 90.degree. from injection angle .alpha..sub.1)
may unevenly accumulate a chemical precursor across the surface of
substrate 8. During a vapor deposition process, substrate 8 may
exposed to the process gas at a predetermined angle of less than
about 90.degree., but more than about 0.degree., to ensure an even
exposure of the process gas. In one embodiment, injection angle
.alpha..sub.1 of slots 510 may be at an angle within a range from
about 20.degree. to about 70.degree., preferably, from about
30.degree. to about 60.degree., and more preferably, from about
40.degree. to about 50.degree., such as about 45.degree.. The
process gas may have a circular pathway inherited from the
injection angle .alpha..sub.1 of slots 510. The circular pathway
usually has a vortex geometry, a helix geometry, a spiral geometry,
a swirl geometry, a twirl geometry, a twist geometry, a coil
geometry, a corkscrew geometry, a curl geometry, a whirlpool
geometry, or derivatives thereof.
[0095] Holes 530 contained within plasma baffle insert 500 may be
positioned at injection angle .alpha..sub.5 to direct a process gas
having flow pattern 912 at injection angle .alpha..sub.5, as
depicted in FIGS. 5F and 9C-9D. In another embodiment, injection
angle .alpha..sub.5 of holes 530 may be at an angle within a range
from about 0.degree. to about 60.degree., preferably, from about
15.degree. to about 50.degree., and more preferably, from about
30.degree. to about 40.degree., such as about 35.degree.. Flow
pattern 912 of the process gas may have a conical pathway inherited
from the injection angle .alpha..sub.5 of holes 530.
[0096] A secondary plasma or back diffusion of gasses within or
above the plasma baffle insert 500 may be avoided by limiting the
width and length of slots 510 and holes 530. Also, a secondary
plasma within or above the plasma baffle insert 500 may be avoided
or limited by positioning slots 510 at a predetermined injection
angle .alpha..sub.1, such that there is not a line-of-sight through
plasma baffle insert 500, along axis 10, from support surface 41 to
gas region 640 (FIG. 1C). The secondary plasma within or above the
plasma baffle insert 500 may also be avoided or limited by
positioning holes 530 at a predetermined injection angle
.alpha..sub.5, such that there is not a line-of-sight through
plasma baffle insert 500, along axial line 538, from support
surface 41 to gas region 640 (FIG. 1F).
[0097] Therefore, the lack of a line-of-sight forms an obscured
pathway down each slot 510 or hole 530. For example, slots 510 may
have a width within a range from about 0.50 mm to about 1.00 mm,
preferably, from about 0.60 mm to about 0.90 mm, and more
preferably, from about 0.70 mm to about 0.80 mm, such as about 0.76
mm (0.030 in). Also, slots 510 may have a length within a range
from about 3 mm to about 60 mm, preferably, from about 10 mm to
about 50 mm, and more preferably, from about 20 mm to about 30 mm,
such as about 21.6 mm (0.850 in). Plasma baffle insert 500 may have
at least about 10 slots, preferably, about 15 slots, and more
preferably, about 20 slots or more. In one example, plasma baffle
insert 500 is constructed from metal (e.g., aluminum or stainless
steel) and has 20 slots that are about 0.76 mm wide and about 2.16
mm long.
[0098] In one embodiment, each hole 530 may have a diameter within
a range from about 0.13 mm (0.005 in) to about 2.54 mm (0.100 in),
preferably, from about 0.26 mm (0.010 in) to about 2.29 mm (0.090
in), and more preferably, from about 0.51 mm (0.020 in) to about
1.90 mm (0.075 in). In one example, each hole 530 may contain upper
passageway 526a having a diameter within a range from about 1.27 mm
(0.050 in) to about 2.29 mm (0.090 in), preferably, from about 1.52
mm (0.060 in) to about 2.03 mm (0.080 in), such as about 1.78 mm
(0.070 in). Also, each hole 530 may contain lower passageway 526b
having a diameter within a range from about 0.38 mm (0.015 in) to
about 1.27 mm (0.050 in), preferably, from about 0.64 mm (0.025 in)
to about 1.02 mm (0.040 in), such as about 0.81 mm (0.032 in). In
one example, each hole 530 contains upper passageway 526a having a
diameter within a range from about 1.5 mm to about 2 mm and lower
passageway 526b having a diameter within a range from about 0.6 mm
to about 1 mm. Plasma baffle insert 500 may have no holes or a
plurality of holes 530, such as about 4 holes, preferably, about 8
holes, and more preferably, about 16 holes or more. In one example,
plasma baffle insert 500 is constructed from metal (e.g., aluminum
or stainless steel) and has 8 holes.
[0099] In another embodiment, upper surface 503 of plasma baffle
insert 500 is sloped from conical nose 520 towards upper rim 514.
In a preferred example, the process gas is directed from holes 612
towards conical nose 520 and down upper surface 503 towards upper
rim 514. In one embodiment, plasma baffle insert 500 is formed with
upper surface 503 sloped downwardly from conical nose 520 to
provide greater mechanical strength and to control varying
conductance and flow rates during a process. Upper surface 503 may
have a slope with an angle .alpha..sub.2 measured between lines 535
and 537. Line 535 extends along the plane of upper surface 503 and
line 537 is perpendicular or substantially perpendicular to axis 10
(FIG. 5B). Upper surface 503 is configured to receive a process gas
along various portions of openings 506 relative to angle
.alpha..sub.2. Therefore, angle .alpha..sub.2 may be at a
predetermined angle in order to eject the process gas from openings
508 of slots 510 with a consistent flow rate along the length of
openings 506. In one embodiment, upper surface 503 may be sloped at
an angle .alpha..sub.2 within a range from about 0.degree. to about
45.degree., preferably, from about 5.degree. to about 30.degree.,
and more preferably, from about 10.degree. to about 200, such as
about 150. In another embodiment, upper surface 503 may be sloped
at an angle .alpha..sub.2 within a range from about 0.degree. to
about 45.degree., preferably, from about 2.degree. to about
20.degree., and more preferably, from about 3.degree. to about
10.degree., such as about 5.degree..
[0100] Slots 510 disposed around conical nose 520 pass through
plasma baffle insert 500 between opening 506 on upper surface 503
(FIG. 5C) and opening 508 on lower surface 504 (FIG. 1C). Openings
506 and 508 may be disposed around conical nose 520 at angle
.alpha..sub.3, measured between line 531 and radial line 533. Line
531 extends along the length of opening 506 and radial line 533
extends perpendicular from axis 10. Line 531 may also extend along
the length of opening 508 (not shown). In one embodiment, openings
506 and 508 may be disposed around conical nose 520 and are
tangential or substantially tangential to dashed circle 539 at
angle .alpha..sub.3. Therefore, line 531, extending along the
length of opening 506, may intersect a point on dashed circle 539
and is tangent or substantially tangent to dashed circle 539 at
angle .alpha..sub.3. Dashed circle 539 may have a radius of a
length within a range from about 0.5 mm to about 5 mm, preferably,
from about 1 mm to about 3 mm, and more preferably, from about 1.5
mm to about 2.5 mm, for example, about 2 mm (about 0.081 inch). In
other embodiments, openings 506 and 508 may be radially disposed
around or tangentially about conical nose 520. Also, openings 506
and 508 may have an angle .alpha..sub.3 at an angle within a range
from about 0.degree. to about 90.degree., preferably, from about
20.degree. to about 45.degree., and more preferably, from about
30.degree. to about 40.degree., such as about 35.degree..
[0101] In one embodiment, plasma screen insert 600 and insulation
cap 700 may be placed between gas manifold assembly 800 and plasma
baffle insert 500 to prohibit or to limit plasma generation
therebetween (FIGS. 1A-1B). Plasma screen insert 600 and insulation
cap 700 may also prohibit or limit the transfer of heat from plasma
baffle insert 500 to gas manifold assembly 800. Plasma screen
insert 600 and insulation cap 700 independently each contain an
electrically insulating material, such as ceramic, quartz, glass,
sapphire or a derivative thereof.
[0102] Plasma screen insert 600 contains inner region 630 and outer
region 632 separated by ring assembly 631 (FIGS. 6A-6B). Ring
assembly 631 contains wall surface 626, inner wall surfaces 605a
and 605b and upper surfaces 604 and 606. Inner region 630 is bound
within inner wall surfaces 605a and 605b. Inner region 630 contains
center portion 601 encompassed by a plurality of holes 612 that
pass through plasma screen insert 600. A process gas within inner
region 630 is exposed to upper surface 602 and is in fluid
communication through holes 612 to lower surface 603 and gas region
640. Center portion 601 generally has no holes between upper
surface 602 and lower surface 603.
[0103] Outer region 632 extends from ring assembly 631 and contains
a plurality of slots 614 that radially extend along upper surface
608. Slots 614 direct a secondary process gas from outer region 632
to gas region 540. Axis 10 extends through the center of plasma
screen insert 600 such that the plurality of holes 612 extend
parallel or substantially parallel to axis 10 and the plurality of
slots extend perpendicular or substantially perpendicular to axis
10.
[0104] FIG. 1A illustrates plasma screen insert 600 positioned on
ring assembly 330 of showerhead 300 and on conical nose 520 of
plasma baffle insert 500. Nose surface 522 is in contact to center
portion 601 of lower surface 603. During a deposition process, a
secondary plasma above plasma screen insert 600 within the gas
region 640 may be avoided by limiting the width and length of slots
614 and the diameter of holes 612. For example, slots 614 may have
a width within a range within a range from about 0.10 mm to about
1.00 mm, preferably, from about 0.20 mm to about 0.80 mm, and more
preferably, from about 0.40 mm to about 0.60 mm, such as about 0.50
mm. Plasma screen insert 600 may have at least about 10 slots,
preferably, about 20 slots, and more preferably, about 36 slots or
more. In one embodiment, plasma screen insert 600 has the same
amount of slots 614 as water box 400 has passageways 440.
[0105] Plasma screen insert 600 contains holes 612 that may have a
diameter within a range from about 0.5 mm to about 5 mm,
preferably, from about 1 mm to about 3 mm, and more preferably,
from about 1.2 mm to about 1.8 mm, such as about 1.50 mm (0.060
in). Plasma screen insert 600 contains a plurality of holes 612 may
have about 50 holes or more, preferably, at least about 100 holes,
and more preferably, about 150 holes or more, for example. In one
example, plasma screen insert 600 is constructed of ceramic and has
36 slots that are about 0.51 mm (0.020 in) wide and about 156 holes
that have a diameter of about 1.52 mm. Preferably, plasma screen
insert 600 has a circular geometry, but may have a different
geometry in alternative embodiments (e.g., oval geometry). Plasma
screen insert 600 may have a diameter within a range from about 1
inch (about 2.54 cm) to about 12 inches (about 30.52 cm),
preferably, from about 2 inches (about 5.08 cm) to about 8 inches
(about 20.36 cm), and more preferably, from about 3 inches (about
7.62 cm) to about 4 inches (about 10.16 cm). Plasma screen insert
600 may have a thickness of about 1 inch (about 2.54 cm) or less,
preferably, about 0.5 inches (about 1.27 cm) or less, and more
preferably, about 0.25 inches (about 0.64 cm), such as about 0.125
inches (about 0.32 cm), where the thickness is measured along a
plane parallel to axis 10 passing through plasma screen insert 600.
In one example of plasma screen insert 600, inner region 630 has a
thickness of about 0.125 inches (about 0.32 cm) or less and ring
assembly 631 has a thickness of about 0.25 inches (about 0.64 cm)
or less.
[0106] Insulation cap 700 has upper surface 704 and lower surfaces
703a, 703b, 703c, 703d and 703e (FIGS. 7A-7C). Insulation cap 700
contains at least one channel extending from upper surface 704 to
lower surfaces 703a-703e. In one example, insulation cap 700
contains only one channel, and a conduit outside of insulation cap
700 may be used to direct a second process gas. In another example,
insulation cap 700 contains multiple channels, such as three
channels, four channels or more (not shown). In a preferred
example, insulation cap 700 contains at least two channels, such as
channels 710 and 720. Channel 720 extends from upper surface 704,
through insulation cap 700, to form expanding channel 722.
Expanding channel 722 tapers from channel 720 at upper portion 721
to lower portion 723 and contains lower surface 703e (FIG. 7B).
Axis 10 may pass through the center of channel 720 and expanding
channel 722 (FIG. 7C). Channel 710 extends from upper surface 704,
through insulation cap 700, to groove 725. In one embodiment,
channel 710 has a smaller radius than channel 710. Groove 725
contains lower surface 703c and is formed encircling the bottom of
insulation cap 700 (FIG. 7B). Upper surface 704 also contains holes
707 which are configured for receiving fasteners (e.g., bolts or
screws) to secure gas manifold assembly 800 thereon.
[0107] Insulation cap 700 may be positioned on water box 400 such
that lower surface 703a contacts and is supported by water box 400.
Lower surfaces 703b, 703c, 703d and 703e either contact plasma
screen insert 600 or form regions therebetween (FIG. 7C). Lower
surface 703d is placed into contact with upper surface 602 of
plasma screen insert 600 to form gas region 744. Gas regions 742
and 744 and gap 726 are each formed between insulation cap 700 and
plasma screen insert 600.
[0108] Gas region 742 is formed between groove 725 containing lower
surface 703c and a portion of outer region 632 of plasma screen
insert 600, including trough 622 and wall surfaces 624 and 626
(FIG. 7C). Gas region 742 extends around and above outer region 632
to encompass gas region 744. Channel 710 is in fluid communication
with gas region 742 through lower surface 703c. Also, gas region
540 is in fluid communication with gas region 742, since slots 614
extend from wall surface 624 to passageways 440, which further
extend through water box 400 and into gas region 540. Slots 614 in
combinations with lower surface 703b of insulation cap 700 forms
these passageways. During a deposition process, a process gas flows
down channel 710, enters gas region 742, flows along trough 622 and
exits through slots 614. Gap 726 generally contains an o-ring after
assembling the components.
[0109] Gas region 744 is formed in part by lower surface 703e of
insulation cap 700 and a portion of inner region 630 of plasma
screen insert 600, including upper surface 602 and center portion
601. Channel 720 is in fluid communication with gas region 744
through lower surface 703e. Channel 720 is perpendicularly in-line
with center portion 601 (along axis 10) which does not contain
holes 612. In a preferred example, the diameter of channel 720 is
smaller than the diameter of center portion 601 to help deflect a
process gas. Expanding channel 722 expands from upper portion 721
to lower portion 723 and covers most of inner region 630 and upper
surface 602 within gas region 744. Also, gas region 640 is in fluid
communication with gas region 744, since holes 612 extend from
through plasma screen insert 600.
[0110] During a deposition process, a process gas flows down
channel 720, enters gas region 744 and exits through holes 612.
Center portion 601 deflects any process gas having a flow path
perpendicular to upper surface 602 coming straight from channel
720. Therefore, the obscured flow path reduces or eliminates a
secondary plasma from forming between plasma baffle insert 500 and
gas manifold assembly 800.
[0111] Expanding channel 722 has an inner diameter which increases
from upper portion 721 to lower portion 723 (FIG. 7B). In one
embodiment, the inner diameter of expanding channel 722 for a
chamber adapted to process a 300 mm diameter substrate is within a
range from about 0.5 cm to about 7 cm, preferably, from about 0.8
cm to about 4 cm, and more preferably, from about 1 cm to about 2.5
cm at upper portion 721 of expanding channel 722 and within a range
from about 2 cm to about 15 cm, preferably, from about 3.5 cm to
about 10 cm, and more preferably, from about 4 cm to about 7 cm at
lower portion 723 of expanding channel 722. In general, the above
dimension apply to an expanding channel adapted to provide a total
gas flow rate within a range from about 100 sccm to about 10,000
sccm.
[0112] In other specific embodiments, the dimension of expanding
channel 722 may be altered to accommodate a certain gas flow
therethrough. In general, a larger gas flow will require a larger
diameter for expanding channel 722. In one embodiment, expanding
channel 722 may be shaped as a truncated cone (including shapes
resembling a truncated cone). Whether a process gas is provided
toward the walls of expanding channel 722 or directly downward
towards substrate 8, the velocity of the gas flow decreases as the
process gas travels through expanding channel 722 due to the
expansion of the process gas. The reduction of the process gas
velocity helps reduce the likelihood the gas flow will blow off
reactants absorbed on the surface of substrate 8.
[0113] The diameter of expanding channel 722 gradually increases
from upper portion 721 to lower portion 723. The gradual increase
of the diameter may allow less of an adiabatic expansion of a
process gas through expanding channel 722 which helps to control
the process gas temperature. For instance, a sudden adiabatic
expansion of a gas delivered through gas conduits 882 and 884 into
channels 820 and 720 may result in a drop of the gas temperature
which may cause condensation of a precursor vapor and formation of
particles. On the other hand, a gradually expanding channel 722
according to some embodiments is believed to provide less of an
adiabatic expansion of a process gas. Therefore, more heat may be
transferred to or from the process gas, and, thus, the gas
temperature may be more easily controlled by controlling the
surrounding temperature (i.e., controlling the temperature by water
box 400). Expanding channel 722 may comprise one or more tapered
inner surfaces, such as a tapered straight surface, a concave
surface, a convex surface, a combination thereof or may comprise
sections of one or more tapered inner surfaces (i.e., a portion
tapered and a portion non-tapered).
[0114] Gap 726 is also formed between insulation cap 700 and plasma
screen insert 600. Gap 726 is formed since a portion of lower
surface 703c within groove 725 does not contact upper surfaces 604
and 606 and inner wall surface 605a of ring assembly 631 contained
on plasma screen insert 600. An o-ring may be positioned within gap
726 while placing insulation cap 700 onto plasma screen insert
600.
[0115] Gas manifold assembly 800 includes conduit assembly 840 and
manifold cap assembly 850 containing gas conduit assembly 830
(FIGS. 8A-8B). Conduit assembly 840 contains gas conduits 836 and
838 within upper manifold 844 and lower manifold 842. Gas manifold
assembly 800 may be attached to lid assembly 100 by a fastener
(e.g., bolt or screw) placed through holes 843. In one embodiment,
conduits 836 and 838, independently, are in fluid communication
with conduit system 34 for providing precursor gases, purge gases,
carrier gases and other process gases (FIG. 1F). In other
embodiments, conduits 836 and 838, independently, may be in fluid
communication with separate process gas supplies, including a
precursor gas supply, a purge gas supply or a carrier gas supply.
Gas conduit assembly 830 contains flanges 832 and 834 on opposite
sides of conduit 831. Flange 834 is coupled to port 117 on lid
support 103 to provide fluid communication from port 117 to conduit
831. Also, flange 832 is coupled to gas inlet 815 on manifold block
806 to provide fluid communication from conduit 831 to conduit 884.
Isolators 808 are disposed on manifold block 806 and provide
further thermal and electric insulation for the ground manifold.
Isolator 808 may be formed from insulating material, such as a
ceramic material, a quartz material or a derivative thereof.
Preferably, isolator 808 is formed from an insulating polymer,
polytetrafluoroethylene (PTFE), such as TEFLON.RTM..
[0116] FIGS. 8B-8D illustrate gas conduit 880 extending from gas
inlet 811 to channel conduit 823 within manifold cap assembly 850.
The interior of channel conduit 823 supports channel 810. A process
gas may follow flow pattern 914 through gas conduit 880 and into
channel 810 contained in channel conduit 823. Channel conduit 821
is in fluid communication with and coupled to gas conduit 882
extending from gas inlet 813 and gas conduit 884 extending from gas
inlet 815. A process gas following flow pattern 916 through gas
conduit 882 and another process gas following flow pattern 918
through gas conduit 884 may combine within channel 820 contained in
channel conduit 821 to form a process gas having flow pattern 922
(FIGS. 8C-8D). Gas channel conduits 821 and 823 may be supported by
gas channel supports 852 and 854 attached within gas manifold
assembly 800.
[0117] In an alternative embodiment, gas conduit 880 and channel
conduit 823 are external from gas manifold assembly 800. Gas
conduit 880 and channel conduit 823 may be in fluid communication
directly to insulation cap 700, plasma screen insert 600, water box
400 or showerhead 300. In another alternative embodiment, gas
manifold assembly 800 includes a plurality of electronic control
valves (not shown). The electronic control valves as used herein
refer to any control valve capable of providing rapid and precise
gas flow to process chamber 50 with valve open and close cycles at
a rate within a range from about 0.01 seconds to about 10 seconds,
preferably from about 0.1 seconds to about 5 seconds, for example,
a longer cycle may last about 3 seconds and a shorter cycle may
last about 0.5 seconds.
[0118] In one example, manifold cap assembly 850 has viewing window
assembly 826 for observing the radiance of a plasma (FIG. 8A).
Viewing window assembly 826 contains lens edge ring 824
encompassing lens 822 and may be positioned on ledge 814,
surrounded by wall surface 816 within manifold block 806. In
another example, manifold cap assembly 850 may contain surface 825
that lacks a viewing window (FIG. 1D). Gas conduit assembly 830 may
be connected to and in fluid communication with port 117 at flange
834 while extended to be connected to and in fluid communication
with gas inlet 813 on manifold block 806.
[0119] In one embodiment, gas conduits 882 and 884 are located
adjacent the upper portion of channel conduit 821 and channel 820
(FIGS. 8C-8D, 9A and 10A). In other embodiments, one or more gas
conduits 882 and 884 may be located along the length of channel 820
between the upper portion of channel 820 and insulation cap 700.
Not wishing to be bound by theory, a process gas flowing from gas
conduits 882 and 884 into and through channel 820 may form a
circular flow pattern, such as flow patterns 922a and 922b (FIG.
10A). Although the exact geometry of flow pattern 922 through
channel 820 is not known, it is believed that the process gas may
travel with flow pattern 922 having a vortex flow pattern, a helix
flow pattern, a spiral flow pattern, a swirl flow pattern, a twirl
flow pattern, a twist flow pattern, a coil flow pattern, a
corkscrew flow pattern, a curl flow pattern, a whirlpool flow
pattern, or derivatives thereof.
[0120] The process gas having flow pattern 922 may be provided
within gas region 920, the combined region of channels 720 and 820
and gas region 744 contained within expanding channel 722 (FIG.
9B). In one aspect, the circular flow patterns of flow pattern 922
may help to establish a more efficient purge of gas region 920 due
to the sweeping action of the circular flow across the inner
surfaces within gas region 920. The circular flow pattern of flow
pattern 922 also provides a consistent and conformal delivery of
process gas across surface 602 of plasma screen insert 600.
[0121] In another embodiment, a process gas passing through gas
region 920 with flow pattern 922 is also directed to center portion
601 of plasma screen insert 600 (FIGS. 9A and 9C). Since center
portion 601 is free of holes 612, the process gas is directed
outwardly, towards holes 612 within upper surface 602. An obscured
pathway between gas region 920 and gas region 640 for the process
gas is efficiently obtained by forming flow pattern 922. The
obscured pathway has many advantages over a non-obscured pathway
having a line-of-sight between gas region 920 and gas region 640
including a reduction or absence of a secondary plasma that may be
formed between plasma baffle insert 500 and gas manifold assembly
800 within gas region 920.
[0122] Flow pattern 922 forms a vertical flow pattern (i.e.,
parallel to axis 10) since the process gas directional conforms to
the angle of holes 612. The process gas passes into gas region 640,
is directed outwardly away from conical nose 520 and into slots 510
or holes 530. The process gas is emitted into process region 60
from slots 510 having flow pattern 922 with an injection angle
.alpha..sub.1, relative from axis 10, as well as from holes 530
having flow pattern 912 with an injection angle .alpha..sub.5,
relative from axis 10 (FIGS. 9B-9D). Slots 510 contained within
plasma baffle insert 500 are positioned at injection angle
.alpha..sub.1 to direct a process gas having a flow pattern at
injection angle .alpha..sub.1. Injection angle .alpha..sub.1 of the
process gas may have an angle within a range from about 20.degree.
to about 70.degree., preferably, from about 30.degree. to about
60.degree., and more preferably, from about 40.degree. to about
50.degree., such as about 45.degree.. Holes 530 contained within
plasma baffle insert 500 are positioned at injection angle
.alpha..sub.5 to direct a process gas having a flow pattern at
injection angle .alpha..sub.5. Injection angle .alpha..sub.5 of the
process gas may have an angle within a range from about 0.degree.
to about 60.degree., preferably, from about 15.degree. to about
50.degree., and more preferably, from about 30.degree. to about
40.degree., such as about 35.degree.. Therefore, flow pattern 922
of the process gas may have a circular pathway inherited from the
injection angle .alpha..sub.1 of slots 510. The circular pathway
usually has a vortex geometry, a helix geometry, a spiral geometry,
or a derivative thereof. Also, flow pattern 912 of the process gas
may have a conical pathway inherited from the injection angle
.alpha..sub.5 of holes 530. Process gas having flow pattern 912 may
be directed to the center of substrate 8. A substrate within
process region 60 may be exposed to the process gas having flow
patterns 912 and 922.
[0123] Also, the injection angle .alpha..sub.1 of slots 510 forms a
secondary obscured pathway for the process gas, which is between
gas region 640 and process region 60. The secondary obscured
pathway further assist the reduction or avoidance of a secondary
plasma that may be formed between plasma baffle insert 500 and gas
manifold assembly 800 within gas region 920 or within openings 506
on upper surface 503 of plasma baffle insert 500.
[0124] In another embodiment, a process gas may have flow pattern
914 while passing through gas region 910, the combined region of
channels 710 and 810 and gas region 742 contained within groove 725
(FIG. 9B). Once the process gas enter gas region 742, flow pattern
914 is altered as the process gas is directed around plasma screen
insert 600 along circular path 923 (FIG. 9A). The process gas is
outwardly directed through slots 614 on plasma screen insert 600
and into gas region 441. An obscured pathway for flow pattern 914
of the process gas is formed between gas region 910 and gas region
441. The obscured pathway has advantages over a non-obscured
pathway having a line-of-sight between gas region 910 and gas
region 441 including a reduction or absence of a secondary plasma
that may be formed between showerhead 300 and gas manifold assembly
800 within gas region 910.
[0125] Flow pattern 914 proceeds from gas region 441 with a
downwardly flow pattern since the process gas directional conforms
to the angle of passageways 440 within water box 400. The process
gas passes into gas region 540, is directed outwardly and across
upper surface 303 of showerhead 300. The process gas is emitted
into process region 60 from holes 310 having flow pattern 914
parallel or substantially parallel of axis 10 (FIG. 9B). A
substrate within process region 60 may be exposed to the process
gas having flow pattern 914. A secondary obscured pathway for the
process gas is formed from gas region 441, to gas region 540 and
into process region 60. The secondary obscured pathway further
assist the reduction or avoidance of a secondary plasma that may be
formed between showerhead 300 and gas manifold assembly 800 within
gas region 910.
[0126] A process gas having circular pathways of flow pattern 922
may be formed by flowing a single process gas or multiple process
gases into gas region 820 (FIGS. 10A-10C). In one embodiment, FIG.
10A reveals a top cross-sectional view into channel 820 of channel
conduit 821 which is adapted to receive a process gas from gas
conduit 882 and a process gas from gas conduit 884. Gas conduit 882
and gas conduit 884 are each coupled to an individual process gas
source. Gas conduits 882 and 884 may each be positioned
independently at angle .alpha..sub.4, measured from center line
915a of gas conduit 884 or center line 915b of gas conduit 882 to
radius line 917 from the center of channel conduit 821, such as
axis 10. Gas conduits 882 and 884 may be positioned to have an
angle .alpha..sub.4 (i.e., when .alpha..sub.4>0.degree.) for
flowing process gases together in a circular direction, such as
flow patterns 922a and 922b. Flow patterns 922a and 922b form flow
pattern 922 of a process gas passing through channel 820 with a
vortex pattern. In one aspect, the circular flow patterns of flow
pattern 922 may help to establish a more efficient purge of process
region 60 due to the sweeping action of the circular flow across
interior surfaces. Also, the circular flow patterns of flow pattern
922 provide a consistent and conformal delivery of process gas to
slots 510.
[0127] In an alternative embodiment, FIG. 10B is a top
cross-sectional view of channel 820 and channel conduit 1021 which
is adapted to receive a single gas flow through gas conduit 1084
coupled to a process gas source. Gas conduit 1084 may be positioned
at angle .alpha..sub.4 from center line 915a of gas conduit 1084
and from radius line 917 from the center of channel conduit 1021,
such as axis 10. Gas conduit 1084 may be positioned having angle
.alpha..sub.4 (i.e., when .alpha..sub.4>0.degree.) to cause a
process gas to flow in a circular direction, such as flow pattern
922a and to continue through channel 820 with a vortex pattern.
[0128] In another alternative embodiment, FIG. 10C is a top
cross-sectional view into channel 820 of channel conduit 1021 which
is adapted to receive three gas flows together, partially together
(i.e., two of three gas flows together), or separately through
three gas inlets, such as gas conduits 1082, 1084 and 1086, each
coupled to an individual process gas source. Each one of gas
conduits 1082, 1084 and 1086 may be positioned independently at
angle .alpha..sub.4 from center lines 915a, 915b and 915c of gas
conduits 1082, 1084 and 1086 and from radius line 917 from the
center of channel conduit 1021, such as axis 10. Each one of gas
conduits 1082, 1084 and 1086 may be positioned having angle
.alpha..sub.4 (i.e., when .alpha..sub.4>0.degree.) to cause
process gases to flow together in a circular direction, such as
flow patterns 922a, 922b and 922c and to continue through channel
820 with a vortex pattern. Further disclosure for adapting process
chamber 50 to flow three or more process gas flows is described in
commonly assigned U.S. Pat. No. 6,916,398, which is incorporated
herein by reference.
[0129] In an example for forming a high-k material, the three gas
flows may contain a hafnium precursor, a silicon precursor and an
oxidizing gas, where, the first flow includes TDEAH, TDMAH, or
HfCl.sub.4, the second flow includes TDMAS, Tris-DMAS or silane and
the third flow includes an oxidizing gas containing water vapor
from a water vapor generator (WVG) system. Further disclosure for a
process to form high-k materials that may be used with process
chamber 50 is described in commonly assigned and co-pending U.S.
Ser. No. 11/127,767, filed May 12, 2005, entitled "Apparatus and
Methods for Atomic Layer Deposition of Hafnium-Containing High-k
Materials," and published as US 2005-0271813, which is incorporated
herein by reference.
[0130] In an alternative embodiment, conduit system 34 may further
contain precursor reservoirs gradually expanding gas conduits
forming nozzles at the ends that are also positioned in fluid
communication with gas inlets 811, 813 and 815. The nozzles or ends
that are useful in some embodiments described herein are further
described in commonly assigned U.S. patent Ser. No. 11/119,388,
filed Apr. 29, 2005, entitled, "Control of Gas Flow and Delivery to
Suppress the Formation of Particles in an MOCVD/ALD System," and
published as US 2005-0252449, which is incorporated herein by
reference to support disclosure of the precursor reservoirs and the
gradually expanding gas conduits. The gas conduit geometry prevents
large temperature drops by providing passing gases a means to
gradually expand through an increasing tapered flow channel. In one
embodiment, the flow channel transitions from the cross-sections of
delivery gas lines with internal diameter within a range from about
3 mm to about 15 mm to gas inlets 811, 813 and 815 with a larger
diameter within a range from about 10 mm to about 20 mm over a
distance within a range from about 30 mm to about 100 mm. A gradual
increase of the diameter of a flow channel allows the expanding
gases to be in near equilibrium and prevents a rapid lost of heat
to maintain a substantially constant temperature. Expanding gas
conduits may comprise one or more tapered inner surfaces such as a
tapered straight surface, a concave surface, a convex surface,
derivatives thereof or combinations thereof or may comprise
sections of one or more tapered inner surfaces (e.g., a portion
tapered and a portion non-tapered).
Ruthenium ALD Process
[0131] Embodiments of the invention provide methods for depositing
a variety of material (e.g., ruthenium materials) on a substrate by
a vapor deposition process, such as atomic layer deposition (ALD)
or plasma-enhanced ALD (PE-ALD). In one aspect, the process has
little or no initiation delay and maintains a fast deposition rate
while forming a ruthenium material. The ruthenium material is
deposited with good step coverage, strong adhesion and contains a
low carbon concentration for high electrical conductivity.
[0132] In one embodiment, a ruthenium material may be formed during
a PE-ALD process containing a constant flow of a reagent gas while
providing sequential pulses of a ruthenium precursor and a plasma.
In another embodiment, a ruthenium material may be formed during
another PE-ALD process that provides sequential pulses of a
ruthenium precursor and a reagent plasma. In both of these
embodiments, the reagent is generally ionized during the process.
Also, the PE-ALD process provides that the plasma may be generated
external from the process chamber, such as by a remote plasma
generator (RPS) system, or preferably, the plasma may be generated
in situ a plasma capable ALD process chamber. During PE-ALD
processes, a plasma may be generated from a microwave (MW)
frequency generator or a radio frequency (RF) generator. In a
preferred example, an in situ plasma is generated by a RF
generator, such as within process chamber 50 or with lid assembly
100. In another embodiment, a ruthenium material may be formed
during a thermal ALD process that provides sequential pulses of a
ruthenium precursor and a reagent.
[0133] An ALD process chamber used during embodiments described
herein may be process chamber 50, as described above, or another
chamber body adapted to receive lid assembly 100, any portion or
component of lid assembly 100 or a derivative thereof. Other ALD
process chambers may also be used during some of the embodiments
described herein and are available from Applied Materials, Inc.,
located in Santa Clara, Calif. A detailed description of an ALD
process chamber may be found in commonly assigned U.S. Pat. Nos.
6,916,398 and 6,878,206, and commonly assigned, co-pending U.S.
patent application Ser. No. 10/281,079, entitled "Gas Delivery
Apparatus for Atomic Layer Deposition", filed on Oct. 25, 2002, and
published as US 2003-0121608, which are hereby incorporated by
reference in their entirety. In another embodiment, a chamber
configured to operate in both an ALD mode as well as a conventional
CVD mode may be used to deposit ruthenium materials is described in
commonly assigned and co-pending U.S. Ser. No. 10/712,690, entitled
"Apparatus and Method for Hybrid Chemical Processing," filed on
Nov. 13, 2003, and published as US 2004-0144311, which are each
incorporated herein by reference in their entirety.
[0134] The ALD process provides that the process chamber may be
pressurized at a pressure within a range from about 0.1 Torr to
about 80 Torr, preferably from about 0.5 Torr to about 10 Torr, and
more preferably, from about 1 to about 5. Also, the chamber or the
substrate may be heated to a temperature of less than about
500.degree. C., preferably within a range from about 100.degree. C.
to about 450.degree. C., and more preferably, from about
150.degree. C. to about 400.degree. C., for example, about
300.degree. C. During PE-ALD processes, a plasma is ignited within
the process chamber for an in situ plasma process, or alternative,
may be formed by an external source, such as a remote plasma
generator (RPS) system. A plasma may be generated a MW generator,
but preferably by a RF generator. For example, a plasma may be
ignited within process chamber 50 or with lid assembly 100. The RF
generator may be set at a frequency within a range from about 100
KHz to about 1.6 MHz. In one example, a RF generator, with a
frequency of 13.56 MHz, may be set to have a power output within a
range from about 100 watts to about 1,000 watts, preferably, from
about 250 watts to about 600 watts, and more preferably, from about
300 watts to about 500 watts. In one example, a RF generator, with
a frequency of 400 KHz, may be set to have a power output within a
range from about 200 watts to about 2,000 watts, preferably, from
about 500 watts to about 1,500 watts. A surface of substrate may be
exposed to a plasma having a power per surface area value within a
range from about 0.01 watts/cm.sup.2 to about 10.0 watts/cm.sup.2,
preferably, from about 0.05 watts/cm.sup.2 to about 6.0
watts/cm.sup.2.
[0135] The substrate may be for example, a silicon substrate having
an interconnect pattern defined in one or more dielectric material
layers formed thereon. In example, the substrate contains a barrier
layer thereon, while in another example, the substrate contains a
dielectric surface. The process chamber conditions such as, the
temperature and pressure, are adjusted to enhance the adsorption of
the process gases on the substrate so as to facilitate the reaction
of the pyrrolyl ruthenium precursors and the reagent gas.
[0136] In one embodiment, the substrate may be exposed to a reagent
gas throughout the whole ALD cycle. The substrate may be exposed to
a ruthenium precursor gas formed by passing a carrier gas (e.g.,
nitrogen or argon) through an ampoule of a ruthenium precursor. The
ampoule may be heated depending on the ruthenium precursor used
during the process. In one example, an ampoule containing
(MeCp)(Py)Ru may be heated to a temperature within a range from
about 60.degree. C. to about 100.degree. C., such as 80.degree. C.
The ruthenium precursor gas usually has a flow rate within a range
from about 100 sccm to about 2,000 sccm, preferably, from about 200
sccm to about 1,000 sccm, and more preferably, from about 300 sccm
to about 700 sccm, for example, about 500 sccm. The ruthenium
precursor gas and the reagent gas may be combined to form a
deposition gas. A reagent gas usually has a flow rate within a
range from about 100 sccm to about 3,000 sccm, preferably, from
about 200 sccm to about 2,000 sccm, and more preferably, from about
500 sccm to about 1,500 sccm. In one example, ammonia is used as a
reagent gas with a flow rate of about 1,500 sccm. The substrate may
be exposed to the ruthenium precursor gas or the deposition gas
containing the ruthenium precursor and the reagent gas for a time
period within a range from about 0.1 seconds to about 8 seconds,
preferably, from about 1 second to about 5 seconds, and more
preferably, from about 2 seconds to about 4 seconds. The flow of
the ruthenium precursor gas may be stopped once the ruthenium
precursor is adsorbed on the substrate. The ruthenium precursor may
be a discontinuous layer, continuous layer or even multiple
layers.
[0137] The substrate and chamber may be exposed to a purge step
after stopping the flow of the ruthenium precursor gas. The flow
rate of the reagent gas may be maintained or adjusted from the
previous step during the purge step. Preferably, the flow of the
reagent gas is maintained from the previous step. Optionally, a
purge gas may be administered into the process chamber with a flow
rate within a range from about 100 sccm to about 2,000 sccm,
preferably, from about 200 sccm to about 1,000 sccm, and more
preferably, from about 300 sccm to about 700 sccm, for example,
about 500 sccm. The purge step removes any excess ruthenium
precursor and other contaminants within the process chamber. The
purge step may be conducted for a time period within a range from
about 0.1 seconds to about 8 seconds, preferably, from about 1
second to about 5 seconds, and more preferably, from about 2
seconds to about 4 seconds. The carrier gas, the purge gas and the
process gas may contain nitrogen, hydrogen, ammonia, argon, neon,
helium or combinations thereof. In a preferred embodiment, the
carrier gas contains nitrogen.
[0138] Thereafter, the flow of the reagent gas may be maintained or
adjusted before igniting a plasma. The substrate may be exposed to
the plasma for a time period within a range from about 0.1 seconds
to about 20 seconds, preferably, from about 1 second to about 10
seconds, and more preferably, from about 2 seconds to about 8
seconds. Thereafter, the plasma power was turned off. In one
example, the reagent may be ammonia, nitrogen, hydrogen or a
combination thereof to form an ammonia plasma, a nitrogen plasma, a
hydrogen plasma or a combined plasma. The reactant plasma reacts
with the adsorbed ruthenium precursor on the substrate to form a
ruthenium material thereon. In one example, the reactant plasma is
used as a reductant to form metallic ruthenium. However, a variety
of reactants may be used to form ruthenium materials having a wide
range of compositions. In one example, a boron-containing reactant
compound (e.g., diborane) is used to form a ruthenium material
containing boride. In another example, a silicon-containing
reactant compound (e.g., silane) is used to form a ruthenium
material containing silicide.
[0139] The process chamber was exposed to a second purge step to
remove excess precursors or contaminants from the previous step.
The flow rate of the reagent gas may be maintained or adjusted from
the previous step during the purge step. An optional purge gas may
be administered into the process chamber with a flow rate within a
range from about 100 sccm to about 2,000 sccm, preferably, from
about 200 sccm to about 1,000 sccm, and more preferably, from about
300 sccm to about 700 sccm, for example, about 500 sccm. The second
purge step may be conducted for a time period within a range from
about 0.1 seconds to about 8 seconds, preferably, from about 1
second to about 5 seconds, and more preferably, from about 2
seconds to about 4 seconds.
[0140] The ALD cycle may be repeated until a predetermined
thickness of the ruthenium material is deposited on the substrate.
The ruthenium material may be deposited with a thickness less than
1,000 .ANG., preferably less than 500 .ANG. and more preferably
from about 10 .ANG. to about 100 .ANG., for example, about 30
.ANG.. The processes as described herein may deposit a ruthenium
material at a rate of at least 0.15 .ANG./cycle, preferably, at
least 0.25 .ANG./cycle, more preferably, at least 0.35 .ANG./cycle
or faster. In another embodiment, the processes as described herein
overcome shortcomings of the prior art relative as related to
nucleation delay. There is no detectable nucleation delay during
many, if not most, of the experiments to deposit the ruthenium
materials.
[0141] In another embodiment, a ruthenium material may be formed
during another PE-ALD process that provides sequentially exposing
the substrate to pulses of a ruthenium precursor and an active
reagent, such as a reagent plasma. The substrate may be exposed to
a ruthenium precursor gas formed by passing a carrier gas through
an ampoule containing a ruthenium precursor, as described herein.
The ruthenium precursor gas usually has a flow rate within a range
from about 100 sccm to about 2,000 sccm, preferably, from about 200
sccm to about 1,000 sccm, and more preferably, from about 300 sccm
to about 700 sccm, for example, about 500 sccm. The substrate may
be exposed to the deposition gas containing the ruthenium precursor
and the reagent gas for a time period within a range from about 0.1
seconds to about 8 seconds, preferably, from about 1 second to
about 5 seconds, and more preferably from about 2 seconds to about
4 seconds. The flow of the ruthenium precursor gas may be stopped
once the ruthenium precursor is adsorbed on the substrate. The
ruthenium precursor may be a discontinuous layer, continuous layer
or even multiple layers.
[0142] Subsequently, the substrate and chamber are exposed to a
purge step. A purge gas may be administered into the process
chamber during the purge step. In one aspect, the purge gas is the
reagent gas, such as ammonia, nitrogen or hydrogen. In another
aspect, the purge gas may be a different gas than the reagent gas.
For example, the reagent gas may be ammonia and the purge gas may
be nitrogen, hydrogen or argon. The purge gas may have a flow rate
within a range from about 100 sccm to about 2,000 sccm, preferably,
from about 200 sccm to about 1,000 sccm, and more preferably, from
about 300 sccm to about 700 sccm, for example, about 500 sccm. The
purge step removes any excess ruthenium precursor and other
contaminants within the process chamber. The purge step may be
conducted for a time period within a range from about 0.1 seconds
to about 8 seconds, preferably, from about 1 second to about 5
seconds, and more preferably, from about 2 seconds to about 4
seconds. A carrier gas, a purge gas and a process gas may contain
nitrogen, hydrogen, ammonia, argon, neon, helium or combinations
thereof.
[0143] The substrate and the adsorbed ruthenium precursor thereon
may be exposed to the reagent gas during the next step of the ALD
process. Optionally, a carrier gas may be administered at the same
time as the reagent gas into the process chamber. The reagent gas
may be ignited to form a plasma. The reagent gas usually has a flow
rate within a range from about 100 sccm to about 3,000 sccm,
preferably, from about 200 sccm to about 2,000 sccm, and more
preferably, from about 500 sccm to about 1,500 sccm. In one
example, ammonia is used as a reagent gas with a flow rate of about
1,500 sccm. The substrate may be exposed to the plasma for a time
period within a range from about 0.1 seconds to about 20 seconds,
preferably, from about 1 second to about 10 seconds, and more
preferably, from about 2 seconds to about 8 seconds. Thereafter,
the plasma power may be turned off. In one example, the reagent may
be ammonia, nitrogen, hydrogen or combinations thereof, while the
plasma may be an ammonia plasma, a nitrogen plasma, a hydrogen
plasma or a combination thereof. The reactant plasma reacts with
the adsorbed ruthenium precursor on the substrate to form a
ruthenium material thereon. Preferably, the reactant plasma is used
as a reductant to form metallic ruthenium. However, a variety of
reactants may be used to form ruthenium materials having a wide
range of compositions, as described herein.
[0144] The process chamber may be exposed to a second purge step to
remove excess precursors or contaminants from the process chamber.
The flow of the reagent gas may have been stopped at the end of the
previous step and started during the purge step, if the reagent gas
is used as a purge gas. Alternative, a purge gas that is different
than the reagent gas may be administered into the process chamber.
The reagent gas or purge gas may have a flow rate within a range
from about 100 sccm to about 2,000 sccm, preferably, from about 200
sccm to about 1,000 sccm, and more preferably, from about 300 sccm
to about 700 sccm, for example, about 500 sccm. The second purge
step may be conducted for a time period within a range from about
0.1 seconds to about 8 seconds, preferably, from about 1 second to
about 5 seconds, and more preferably, from about 2 seconds to about
4 seconds.
[0145] The ALD cycle may be repeated until a predetermined
thickness of the ruthenium material is deposited on the substrate.
The ruthenium material may be deposited with a thickness less than
1,000 .ANG., preferably less than 500 .ANG. and more preferably
from about 10 .ANG. to about 100 .ANG., for example, about 30
.ANG.. The processes as described herein may deposit a ruthenium
material at a rate of at least 0.15 .ANG./cycle, preferably, at
least 0.25 .ANG./cycle, more preferably, at least 0.35 .ANG./cycle
or faster. In another embodiment, the processes as described herein
overcome shortcomings of the prior art relative as related to
nucleation delay. There is no detectable nucleation delay during
many, if not most, of the experiments to deposit the ruthenium
materials.
[0146] Generally, in order to use a ruthenocene compound during an
ALD process, a surface treatment step is required, unless the
surface is terminated with a hydroxyl group, such as --OH, or an
electron-rich surface, such as a metallic layer. On a barrier layer
such as tantalum nitride, ruthenocene precursors do not deposit
ruthenium materials via ALD processes without a pre-treatment step.
Even with a pre-treatment step, such as the hydroxylation of the
barrier surface, the randomly placed nucleation sites cause
ruthenocene to form satellites or islands of ruthenium during the
deposition process. Therefore, an ALD process using a ruthenocene
precursor generally deposits a ruthenium material having an
increased electrical resistance, probably due to the unevenness of
the ruthenium material. Also, the deposition process may suffer a
nucleation delay due to the ruthenocene precursor. Furthermore, a
high adsorption temperature above 400.degree. C. is usually
required for ruthenocene precursors. Such a high temperatures may
damage device structure within a sensitive low-k dielectric
environment, for example, within a copper back end of line (BEOL)
process. Hence, it is preferred to perform ALD processes at a
temperature less than 400.degree. C., preferably, less than
350.degree. C. Further, ruthenium materials deposited from
ruthenocene precursors used during an ALD process on dielectric
surfaces tend to fail tape testing due to the low adhesion of the
underlying layer. Therefore, in many embodiments, ruthenocene
compounds, such as bis(ethylcyclopentadienyl) ruthenium,
bis(cyclopentadienyl) ruthenium and
bis(pentamethylcyclopentadienyl) ruthenium are less desirable
ruthenium precursors.
[0147] Embodiments of the invention include improved methodologies
overcoming disadvantages of the prior art, and preferred precursors
and chemistries providing additional advantages over the prior art.
A family of ruthenium precursors useful to form a ruthenium
material during the deposition process described herein includes
pyrrolyl ruthenium precursors. A further disclosure of ALD
processes for depositing ruthenium materials is described in
commonly assigned and co-pending U.S. Ser. No. 11/470,466, filed
Sep. 6, 2006, and entitled "Atomic Layer Deposition Process for
Ruthenium Materials," which is incorporated herein in its entirety
by reference. The pyrrolyl ligand provides the pyrrolyl ruthenium
precursor advantages over previous ruthenium precursors (e.g.,
ruthenocene and derivatives thereof) during an ALD process. The
pyrrolyl ligand is more thermodynamically stable than many ligands,
as well as forms a very volatile chemical precursor. A pyrrolyl
ruthenium precursor contains ruthenium and at least one pyrrolyl
ligand or at least one pyrrolyl derivative ligand. A pyrrolyl
ruthenium precursor may have a pyrrolyl ligand, such as: ##STR2##
where R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each
independently hydrogen, an alkyl group (e.g., methyl, ethyl,
propyl, butyl, amyl or higher), an amine group, an alkoxy group, an
alcohol group, an aryl group, another pyrrolyl group (e.g.,
2,2'-bipyrrolyl), a pyrazole group, derivatives thereof or
combinations thereof. The pyrrolyl ligand may have any two or more
of R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 connected
together by a chemical group. For example, R.sub.2 and R.sub.3 may
be a portion of a ring structure such as an indolyl group or
derivative thereof. A pyrrolyl ruthenium precursor as used herein
refers to any chemical compound containing ruthenium and at least
one pyrrolyl ligand or at least one derivative of a pyrrolyl
ligand. In preferred examples, a pyrrolyl ruthenium precursor may
include bis(tetramethylpyrrolyl) ruthenium,
bis(2,5-dimethylpyrrolyl) ruthenium, bis(2,5-diethylpyrrolyl)
ruthenium, bis(tetraethylpyrrolyl) ruthenium, pentadienyl
tetramethylpyrrolyl ruthenium, pentadienyl 2,5-dimethylpyrrolyl
ruthenium, pentadienyl tetraethylpyrrolyl ruthenium, pentadienyl
2,5-diethylpyrrolyl ruthenium, 1,3-dimethylpentadienyl pyrrolyl
ruthenium, 1,3-diethylpentadienyl pyrrolyl ruthenium,
methylcyclopentadienyl pyrrolyl ruthenium, ethylcyclopentadienyl
pyrrolyl ruthenium, 2-methylpyrrolyl pyrrolyl ruthenium,
2-ethylpyrrolyl pyrrolyl ruthenium or a derivative thereof.
[0148] An important precursor characteristic is to have a favorable
vapor pressure. Deposition precursors may have gas, liquid or solid
states at ambient temperature and pressure. However, within the ALD
chamber, precursors are usually volatilized as gas or plasma.
Precursors are usually heated prior to delivery into the process
chamber. Although many variables affect the deposition rate during
an ALD process to form ruthenium material, the size of the ligand
on a pyrrolyl ruthenium precursor is an important consideration in
order to achieve a predetermined deposition rate. The size of the
ligand does contribute to determining the specific temperature and
pressure required to vaporize the pyrrolyl ruthenium precursor.
Furthermore, a pyrrolyl ruthenium precursor has a particular ligand
steric hindrance proportional to the size of the ligands. In
general, larger ligands provide more steric hindrance. Therefore,
less molecules of a precursor more bulky ligands may be adsorbed on
a surface during the half reaction while exposing the substrate to
the precursor than if the precursor contained less bulky ligands.
The steric hindrance effect limits the amount of adsorbed
precursors on the surface. Therefore, a monolayer of a pyrrolyl
ruthenium precursor may be formed to contain a more molecularly
concentrated by decreasing the steric hindrance of the ligand(s).
The overall deposition rate is proportionally related to the amount
of adsorbed precursor on the surface, since an increased deposition
rate is usually achieved by having more of the precursor adsorbed
to the surface. Ligands that contain smaller functional groups
(e.g., hydrogen or methyl) generally provide less steric hindrance
than ligands that contain larger functional groups (e.g., aryl).
Also, the position on the ligand motif may affect the steric
hindrance of the precursor. Generally, the inner positions, R.sub.2
and R.sub.5, have less affect than does the outer positions R.sub.3
and R.sub.4. For example, a pyrrolyl ruthenium precursor containing
R.sub.2 and R.sub.5 equal to hydrogen groups and R.sub.3 and
R.sub.4 equal to methyl groups has more steric hindrance than a
pyrrolyl ruthenium precursor containing R.sub.2 and R.sub.5 equal
to methyl groups and R.sub.3 and R.sub.4 equal to hydrogen
groups.
[0149] A pyrrolyl ligand may be abbreviated by "py" and a pyrrolyl
derivative ligand may be abbreviated by "R-py." Exemplary pyrrolyl
ruthenium precursors useful to form a ruthenium material during the
deposition process described herein include alkyl pyrrolyl
ruthenium precursors (e.g., (R.sub.x-py)Ru), bis(pyrrolyl)
ruthenium precursors (e.g., (py).sub.2Ru) and dienyl pyrrolyl
ruthenium precursors (e.g., (Cp)(py)Ru). Examples of alkyl pyrrolyl
ruthenium precursors include methylpyrrolyl ruthenium,
ethylpyrrolyl ruthenium, propylpyrrolyl ruthenium, dimethylpyrrolyl
ruthenium, diethylpyrrolyl ruthenium, dipropylpyrrolyl ruthenium,
trimethylpyrrolyl ruthenium, triethylpyrrolyl ruthenium,
tetramethylpyrrolyl ruthenium, tetraethylpyrrolyl ruthenium or
derivatives thereof. Examples of bis(pyrrolyl) ruthenium precursors
include bis(pyrrolyl) ruthenium, bis(methylpyrrolyl) ruthenium,
bis(ethylpyrrolyl) ruthenium, bis(propylpyrrolyl) ruthenium,
bis(dimethylpyrrolyl) ruthenium, bis(diethylpyrrolyl) ruthenium,
bis(dipropylpyrrolyl) ruthenium, bis(trimethylpyrrolyl) ruthenium,
bis(triethylpyrrolyl) ruthenium, bis(tetramethylpyrrolyl)
ruthenium, bis(tetraethylpyrrolyl) ruthenium, methylpyrrolyl
pyrrolyl ruthenium, ethylpyrrolyl pyrrolyl ruthenium,
propylpyrrolyl pyrrolyl ruthenium, dimethylpyrrolyl pyrrolyl
ruthenium, diethylpyrrolyl pyrrolyl ruthenium, dipropylpyrrolyl
pyrrolyl ruthenium, trimethylpyrrolyl pyrrolyl ruthenium,
triethylpyrrolyl pyrrolyl ruthenium, tetramethylpyrrolyl pyrrolyl
ruthenium, tetraethylpyrrolyl pyrrolyl ruthenium or derivatives
thereof.
[0150] A dienyl pyrrolyl ruthenium precursor contains at least one
dienyl ligand and at least one pyrrolyl ligand. The dienyl ligand
may contain a carbon backbone with as little as four carbon atoms
or as many as about ten carbon atoms, preferably, about five or
six. The dienyl ligand may have a ring structure (e.g.,
cyclopentadienyl) or may be an open alkyl chain (e.g.,
pentadienyl). Also, dienyl ligand may contain no alkyl groups, one
alkyl group or many alkyl groups.
[0151] In one embodiment, the dienyl pyrrolyl ruthenium precursor
contains a pentadienyl ligand or an alkylpentadienyl ligand.
Examples of pentadienyl pyrrolyl ruthenium precursors include
pentadienyl pyrrolyl ruthenium, pentadienyl methylpyrrolyl
ruthenium, pentadienyl ethylpyrrolyl ruthenium, pentadienyl
propylpyrrolyl ruthenium, pentadienyl dimethylpyrrolyl ruthenium,
pentadienyl diethylpyrrolyl ruthenium, pentadienyl dipropylpyrrolyl
ruthenium, pentadienyl trimethylpyrrolyl ruthenium, pentadienyl
triethylpyrrolyl ruthenium, pentadienyl tetramethylpyrrolyl
ruthenium, pentadienyl tetraethylpyrrolyl ruthenium or derivatives
thereof. Examples of alkylpentadienyl pyrrolyl ruthenium precursors
include alkylpentadienyl pyrrolyl ruthenium, alkylpentadienyl
methylpyrrolyl ruthenium, alkylpentadienyl ethylpyrrolyl ruthenium,
alkylpentadienyl propylpyrrolyl ruthenium, alkylpentadienyl
dimethylpyrrolyl ruthenium, alkylpentadienyl diethylpyrrolyl
ruthenium, alkylpentadienyl dipropylpyrrolyl ruthenium,
alkylpentadienyl trimethylpyrrolyl ruthenium, alkylpentadienyl
triethylpyrrolyl ruthenium, alkylpentadienyl tetramethylpyrrolyl
ruthenium, alkylpentadienyl tetraethylpyrrolyl ruthenium or
derivatives thereof.
[0152] In another embodiment, the dienyl pyrrolyl ruthenium
precursor contains a cyclopentadienyl ligand or an
alkylcyclopentadienyl ligand. Examples of cyclopentadienyl pyrrolyl
ruthenium precursors include cyclopentadienyl pyrrolyl ruthenium,
cyclopentadienyl methylpyrrolyl ruthenium, cyclopentadienyl
ethylpyrrolyl ruthenium, cyclopentadienyl propylpyrrolyl ruthenium,
cyclopentadienyl dimethylpyrrolyl ruthenium, cyclopentadienyl
diethylpyrrolyl ruthenium, cyclopentadienyl dipropylpyrrolyl
ruthenium, cyclopentadienyl trimethylpyrrolyl ruthenium,
cyclopentadienyl triethylpyrrolyl ruthenium, cyclopentadienyl
tetramethylpyrrolyl ruthenium, cyclopentadienyl tetraethylpyrrolyl
ruthenium or derivatives thereof. Examples of alkylcyclopentadienyl
pyrrolyl ruthenium precursors include alkylcyclopentadienyl
pyrrolyl ruthenium, alkylcyclopentadienyl methylpyrrolyl ruthenium,
alkylcyclopentadienyl ethyl pyrrolyl ruthenium,
alkylcyclopentadienyl propylpyrrolyl ruthenium,
alkylcyclopentadienyl dimethylpyrrolyl ruthenium,
alkylcyclopentadienyl diethylpyrrolyl ruthenium,
alkylcyclopentadienyl dipropylpyrrolyl ruthenium,
alkylcyclopentadienyl trimethylpyrrolyl ruthenium,
alkylcyclopentadienyl triethylpyrrolyl ruthenium,
alkylcyclopentadienyl tetramethylpyrrolyl ruthenium,
alkylcyclopentadienyl tetraethylpyrrolyl ruthenium or derivatives
thereof.
[0153] In another embodiment, a ruthenium precursor may not contain
a pyrrolyl ligand or a pyrrolyl derivative ligand, but instead,
contain at least one open chain dienyl ligand, such as
CH.sub.2CRCHCRCH.sub.2, where R is independently an alkyl group or
hydrogen. A ruthenium precursor may have two open-chain dienyl
ligands, such as pentadienyl or heptadienyl. A bis(pentadienyl)
ruthenium compound has a generic chemical formula
(CH.sub.2CRCHCRCH.sub.2).sub.2Ru, where R is independently an alkyl
group or hydrogen. Usually, R is independently hydrogen, methyl,
ethyl, propyl or butyl. Therefore, ruthenium precursors may include
bis(dialkylpentadienyl) ruthenium compounds, bis(alkylpentadienyl)
ruthenium compounds, bis(pentadienyl) ruthenium compounds or
combinations thereof. Examples of ruthenium precursors include
bis(2,4-dimethylpentadienyl) ruthenium, bis(2,4-diethylpentadienyl)
ruthenium, bis(2,4-diisopropylpentadienyl) ruthenium,
bis(2,4-ditertbutylpentadienyl) ruthenium, bis(methylpentadienyl)
ruthenium, bis(ethylpentadienyl) ruthenium,
bis(isopropylpentadienyl) ruthenium, bis(tertbutylpentadienyl)
ruthenium, derivatives thereof or combinations thereof. In some
embodiments, other ruthenium precursors include
tris(2,2,6,6-tetramethyl-3,5-heptanedionato) ruthenium, dicarbonyl
pentadienyl ruthenium, ruthenium acetyl acetonate,
2,4-dimethylpentadienyl cyclopentadienyl ruthenium,
bis(2,2,6,6-tetramethyl-3,5-heptanedionato) (1,5-cyclooctadiene)
ruthenium, 2,4-dimethylpentadienyl methylcyclopentadienyl
ruthenium, 1,5-cyclooctadiene cyclopentadienyl ruthenium,
1,5-cyclooctadiene methylcyclopentadienyl ruthenium,
1,5-cyclooctadiene ethylcyclopentadienyl ruthenium,
2,4-dimethylpentadienyl ethylcyclopentadienyl ruthenium,
2,4-dimethylpentadienyl isopropylcyclopentadienyl ruthenium,
bis(N,N-dimethyl 1,3-tetramethyl diiminato) 1,5-cyclooctadiene
ruthenium, bis(N,N-dimethyl 1,3-dimethyl diiminato)
1,5-cyclooctadiene ruthenium, bis(allyl) 1,5-cyclooctadiene
ruthenium, .eta..sup.6-C.sub.6H.sub.6 1,3-cyclohexadiene ruthenium,
bis(1,1-dimethyl-2-aminoethoxylato) 1,5-cyclooctadiene ruthenium,
bis(1,1-dimethyl-2-aminoethylaminato) 1,5-cyclooctadiene ruthenium,
derivatives thereof, or combinations thereof.
[0154] The various ruthenium precursors containing a pyrrolyl
ligand, an open chain dienyl ligand or a combination thereof may be
used with at least one reagent to form a ruthenium material. The
ruthenium precursor and the reagent may be sequentially introduced
into the process chamber during a thermal ALD process or a PE-ALD
process. A suitable reagent for forming a ruthenium material may be
a reducing gas and include hydrogen (e.g., H.sub.2 or atomic-H),
atomic-N, ammonia (NH.sub.3), hydrazine (N.sub.2H.sub.4), silane
(SiH.sub.4), disilane (Si.sub.2H.sub.6), trisilane
(Si.sub.3H.sub.8), tetrasilane (Si.sub.4H.sub.10), dimethylsilane
(SiC.sub.2H.sub.8), methyl silane (SiCH.sub.6), ethylsilane
(SiC.sub.2H.sub.8), chlorosilane (ClSiH.sub.3), dichlorosilane
(Cl.sub.2SiH.sub.2), hexachlorodisilane (Si.sub.2Cl.sub.6), borane
(BH.sub.3), diborane (B.sub.2H.sub.6), triborane, tetraborane,
pentaborane, triethylborane (Et.sub.3B), derivatives thereof,
plasmas thereof, or combinations thereof.
[0155] In an alternative embodiment, the reagent gas may include
oxygen-containing gases, such as oxygen (e.g., O.sub.2), nitrous
oxide (N.sub.2O), nitric oxide (NO), nitrogen dioxide (NO.sub.2),
derivatives thereof or combinations thereof. Furthermore, the
traditional reductants may be combined with the oxygen-containing
reagents to form a reagent gas. Oxygen-containing gases that may be
used during deposition processes to form ruthenium materials have
traditionally been used in the chemical art as an oxidant. However,
ligands on a metal-organic compound containing a noble metal (e.g.,
Ru) are usually more susceptible to the oxygen-containing
reductants than the noble metal. Therefore, the ligand is generally
oxidized from the metal center while the metal ion is reduced to
form the elemental metal. In one embodiment, the reagent gas
contains ambient oxygen from the air that may be dried over sieves
to reduce ambient water. Further disclosure useful for processes
described herein, including a process for depositing a ruthenium
material by using an oxygen-containing gas, is further described in
commonly assigned and co-pending U.S. Ser. No. 10/811,230, entitled
"Ruthenium Layer Formation for Copper Film Deposition," filed Mar.
26, 2004, and published as US 2004-0241321, which is incorporated
herein in its entirety by reference.
[0156] The time interval for the pulse of the ruthenium precursor
is variable depending upon a number of factors such as, for
example, the volume capacity of the process chamber employed, the
vacuum system coupled thereto and the volatility/reactivity of the
reactants used during the ALD process. For example, (1) a
large-volume process chamber may lead to a longer time to stabilize
the process conditions such as, for example, carrier/purge gas flow
and temperature, requiring a longer pulse time; (2) a lower flow
rate for the process gas may also lead to a longer time to
stabilize the process conditions requiring a longer pulse time; and
(3) a lower chamber pressure means that the process gas is
evacuated from the process chamber more quickly requiring a longer
pulse time. In general, the process conditions are advantageously
selected so that a pulse of the ruthenium precursor provides a
sufficient amount of precursor so that at least a monolayer of the
ruthenium precursor is adsorbed on the substrate. Thereafter,
excess ruthenium precursor remaining in the chamber may be removed
from the process chamber by the constant carrier gas stream in
combination with the vacuum system.
[0157] The time interval for each of the pulses of the ruthenium
precursor and the reagent gas may have the same duration. That is,
the duration of the pulse of the ruthenium precursor may be
identical to the duration of the pulse of the reagent gas. For such
an embodiment, a time interval (T.sub.1) for the pulse of the
ruthenium precursor is equal to a time interval (T.sub.2) for the
pulse of the reagent gas.
[0158] Alternatively, the time interval for each of the pulses of
the ruthenium precursor and the reagent gas may have different
durations. That is, the duration of the pulse of the ruthenium
precursor may be shorter or longer than the duration of the pulse
of the reagent gas. For such an embodiment, a time interval
(T.sub.1) for the pulse of the ruthenium precursor is different
than the time interval (T.sub.2) for the pulse of the reagent
gas.
[0159] In addition, the periods of non-pulsing between each of the
pulses of the ruthenium precursor and the reagent gas may have the
same duration. That is, the duration of the period of non-pulsing
between each pulse of the ruthenium precursor and each pulse of the
reagent gas is identical. For such an embodiment, a time interval
(T.sub.3) of non-pulsing between the pulse of the ruthenium
precursor and the pulse of the reagent gas is equal to a time
interval (T.sub.4) of non-pulsing between the pulse of the reagent
gas and the pulse of the ruthenium precursor. During the time
periods of non-pulsing only the constant carrier gas stream is
provided to the process chamber.
[0160] Alternatively, the periods of non-pulsing between each of
the pulses of the ruthenium precursor and the reagent gas may have
different duration. That is, the duration of the period of
non-pulsing between each pulse of the ruthenium precursor and each
pulse of the reagent gas may be shorter or longer than the duration
of the period of non-pulsing between each pulse of the reagent gas
and the ruthenium precursor. For such an embodiment, a time
interval (T.sub.3) of non-pulsing between the pulse of the
ruthenium precursor and the pulse of the reagent gas is different
from a time interval (T.sub.4) of non-pulsing between the pulse of
the reagent gas and the pulse of ruthenium precursor. During the
time periods of non-pulsing only the constant carrier gas stream is
provided to the process chamber.
[0161] Additionally, the time intervals for each pulse of the
ruthenium precursor, the reagent gas and the periods of non-pulsing
therebetween for each deposition cycle may have the same duration.
For such an embodiment, a time interval (T.sub.1) for the ruthenium
precursor, a time interval (T.sub.2) for the reagent gas, a time
interval (T.sub.3) of non-pulsing between the pulse of the
ruthenium precursor and the pulse of the reagent gas and a time
interval (T.sub.4) of non-pulsing between the pulse of the reagent
gas and the pulse of the ruthenium precursor each have the same
value for each deposition cycle. For example, in a first deposition
cycle (C.sub.1), a time interval (T.sub.1) for the pulse of the
ruthenium precursor has the same duration as the time interval
(T.sub.1) for the pulse of the ruthenium precursor in subsequent
deposition cycles (C.sub.2 . . . C.sub.n). Similarly, the duration
of each pulse of the reagent gas and the periods of non-pulsing
between the pulse of the ruthenium precursor and the reagent gas in
the first deposition cycle (C.sub.1) is the same as the duration of
each pulse of the reagent gas and the periods of non-pulsing
between the pulse of the ruthenium precursor and the reagent gas in
subsequent deposition cycles (C.sub.2 . . . C.sub.n),
respectively.
[0162] Alternatively, the time intervals for at least one pulse of
the ruthenium precursor, the reagent gas and the periods of
non-pulsing therebetween for one or more of the deposition cycles
of the ruthenium material deposition process may have different
durations. For such an embodiment, one or more of the time
intervals (T.sub.1) for the pulses of the ruthenium precursor, the
time intervals (T.sub.2) for the pulses of the reagent gas, the
time intervals (T.sub.3) of non-pulsing between the pulse of the
ruthenium precursor and the reagent gas and the time intervals
(T.sub.4) of non-pulsing between the pulses of the reagent gas and
the ruthenium precursor may have different values for one or more
deposition cycles of the cyclical deposition process. For example,
in a first deposition cycle (C.sub.1), the time interval (T.sub.1)
for the pulse of the ruthenium precursor may be longer or shorter
than one or more time interval (T.sub.1) for the pulse of the
ruthenium precursor in subsequent deposition cycles (C.sub.2 . . .
C.sub.n). Similarly, the durations of the pulses of the reagent gas
and the periods of non-pulsing between the pulse of the ruthenium
precursor and the reagent gas in the first deposition cycle
(C.sub.1) may be the same or different than the duration of each
pulse of the reagent gas and the periods of non-pulsing between the
pulse of the ruthenium precursor and the reagent gas in subsequent
deposition cycles (C.sub.2 . . . C.sub.n).
[0163] In some embodiments, a constant flow of a carrier gas or a
purge gas may be provided to the process chamber modulated by
alternating periods of pulsing and non-pulsing where the periods of
pulsing alternate between the ruthenium precursor and the reagent
gas along with the carrier/purge gas stream, while the periods of
non-pulsing include only the carrier/purge gas stream.
[0164] A PE-ALD process chamber (e.g., process chamber 50) may be
used to form many materials including tantalum, tantalum nitride,
titanium, titanium nitride, ruthenium, tungsten, tungsten nitride
and other materials. In one embodiment, ruthenium material may be
deposited on a barrier layer containing tantalum and/or tantalum
nitride, which may be formed during an ALD process as described in
commonly assigned U.S. Pat. No. 6,951,804, which is incorporated
herein in its entirety by reference. Further disclosure of
processes for depositing a tungsten material on a ruthenium
material is further described in commonly assigned and co-pending
U.S. Ser. No. 11/009,331, entitled "Ruthenium as an Underlayer for
Tungsten Film Deposition," filed Dec. 10, 2004, and published as US
2006-0128150, which is incorporated herein in its entirety by
reference.
[0165] In one example, a copper seed layer may be formed on the
ruthenium material by a CVD process and thereafter, bulk copper is
deposited to fill the interconnect by an ECP process. In another
example, a copper seed layer may be formed on the ruthenium
material by a PVD process and thereafter, bulk copper is deposited
to fill the interconnect by an ECP process. In another example, a
copper seed layer may be formed on the ruthenium material by an
electroless process and thereafter, bulk copper is deposited to
fill the interconnect by an ECP process. In another example, the
ruthenium material serves as a seed layer to which a copper bulk
fill is directly deposited by an ECP process or an electroless
deposition process.
[0166] In another example, a tungsten seed layer may be formed on
the ruthenium material by an ALD process and thereafter, bulk
tungsten is deposited to fill the interconnect by a CVD process or
a pulsed-CVD process. In another example, a tungsten seed layer may
be formed on the ruthenium material by a PVD process and
thereafter, bulk tungsten is deposited to fill the interconnect by
a CVD process or a pulsed-CVD process. In another example, a
tungsten seed layer may be formed on the ruthenium material by an
ALD process and thereafter, bulk tungsten is deposited to fill the
interconnect by an ECP process. In another example, the ruthenium
material serves as a seed layer to which a tungsten bulk fill is
directly deposited by a CVD process or a pulsed-CVD process.
[0167] Several integration sequence are conducted in order to form
a ruthenium material within an interconnect. In one example, the
subsequent steps follow: a) pre-clean of the substrate; b)
deposition of a barrier layer (e.g., ALD of TaN); c) deposition of
ruthenium by ALD; and d) deposition of seed copper by electroless,
ECP or PVD followed by deposition of bulk copper by ECP. In another
example, the subsequent steps follow: a) deposition of a barrier
layer (e.g., ALD of TaN); b) punch through step; c) deposition of
ruthenium by ALD; and d) deposition of seed copper by electroless,
ECP or PVD followed by deposition of bulk copper by ECP. In another
example, the subsequent steps follow: a) deposition of ruthenium by
ALD; b) punch through step; c) deposition of ruthenium by ALD; and
d) deposition of seed copper by electroless, ECP or PVD followed by
deposition of bulk copper by electroless, ECP or PVD. In another
example, the subsequent steps follow: a) deposition of ruthenium by
ALD; b) punch through step; c) deposition of ruthenium by ALD; and
d) deposition of copper by electroless or ECP. In another
embodiment, the subsequent steps follow: a) pre-clean of the
substrate; b) deposition of ruthenium by ALD; and c) deposition of
seed copper by electroless, ECP or PVD followed by deposition of
bulk copper by ECP. In another example, the subsequent steps
follow: a) deposition of a barrier layer (e.g., ALD of TaN); b)
deposition of ruthenium by ALD; c) punch through step; d)
deposition of ruthenium by ALD; and e) deposition of seed copper by
electroless, ECP or PVD followed by deposition of bulk copper by
ECP. In another example, the subsequent steps follow: a) deposition
of a barrier layer (e.g., ALD of TaN); b) punch through step; c)
deposition of a barrier layer (e.g., ALD of TaN); d) deposition of
ruthenium by ALD; and d) deposition of seed copper by electroless,
ECP or PVD; and e) deposition of bulk copper by ECP. In one
example, the subsequent steps follow: a) pre-clean of the
substrate; b) deposition of a barrier layer (e.g., ALD of TaN); c)
deposition of ruthenium by ALD; and d) deposition of copper bulk by
electroless or ECP.
[0168] The pre-clean steps include methods to clean or purify the
via, such as the removal of residue at the bottom of the via (e.g.,
carbon) or reduction of copper oxide to copper metal. Punch through
steps include a method to remove material (e.g., barrier layer)
from the bottom of the via to expose conductive layer, such as
copper. Further disclosure of punch through steps is described in
more detail in the commonly assigned, U.S. Pat. No. 6,498,091,
which is incorporated herein in its entirety by reference. The
punch through steps may be conducted within a process chamber, such
as either a barrier chamber or a clean chamber. In embodiments of
the invention, clean steps and punch through steps are applied to
ruthenium barrier layers. Further disclosure of overall integrated
methods are described in more detail in the commonly assigned, U.S.
Pat. No. 7,049,226, which is incorporated herein in its entirety by
reference.
[0169] The pyrrolyl ruthenium precursors and deposition chemistries
utilized in the various embodiments provide further significant
advantages. The layers formed by the present ruthenium
methodologies and precursors, such as pyrrolyl ruthenium
precursors, have high nucleation density and uniformity. This is
believed to promote freedom from surface defects such as satellites
or islands in the resulting ruthenium material, in contrast to
layers deposited by prior art methods and where prior methods
employ sole ruthenocene compounds.
[0170] The pyrrolyl ruthenium precursors used to form ruthenium
materials provide little or no nucleation delay during the ALD
process. Also, the ruthenium material deposited has a low carbon
concentration and therefore a high electrical conductance.
[0171] Also, the pyrrolyl ruthenium precursor and the reagents are
utilized in various embodiments during the ALD processes to deposit
a ruthenium material on a barrier layer, especially a tantalum
nitride barrier layer. Unlike other ALD processes that use
ruthenocene, the present ruthenium methodologies and precursors are
not limited with the need to pre-treat the barrier layer prior to
the deposition of a ruthenium material. Excess process steps, such
as pretreatment steps, are avoided by applying a pyrrolyl ruthenium
precursor during an ALD process to reduce the overall throughput of
the production line.
[0172] Further, ruthenium materials deposited with the present
methodologies, especially when employing a pyrrolyl ruthenium
precursor, have superior adhesion properties to barrier layers as
well as dielectric materials. It is believe the superior adhesion
at least in part is due to the higher degree of uniformity and
nucleation density, whereby a more level surface and fewer surface
defects results. Furthermore, ruthenocene compounds generally
require a temperature above 400.degree. C. in order to become
adsorbed to a substrate surface needed during an ALD process.
However, since the threshold of many low-k devices is around
400.degree. C., ruthenocene compounds are not desirable ruthenium
precursors for ALD processes.
[0173] The ruthenium materials formed from a pyrrolyl ruthenium
precursor during the ALD processes as described herein generally
have a sheet resistance of less than 2,000 .OMEGA./sq, preferably,
less than 1,000 .OMEGA./sq, and more preferably, less than 500
.OMEGA./sq. For example, a ruthenium material may have a sheet
resistance within a range from about 10 .OMEGA./sq to about 250
.OMEGA./sq.
[0174] A "substrate surface," as used herein, refers to any
substrate or material surface formed on a substrate upon which film
processing is performed during a fabrication process. For example,
a substrate surface on which processing can be performed include
materials such as silicon, silicon oxide, strained silicon, silicon
on insulator (SOI), carbon doped silicon oxides, silicon nitride,
doped silicon, germanium, gallium arsenide, glass, sapphire, and
any other materials such as metals, metal nitrides, metal alloys,
and other conductive materials, depending on the application.
Barrier layers, metals or metal nitrides on a substrate surface
include titanium, titanium nitride, tungsten nitride, tantalum and
tantalum nitride. Substrates may have various dimensions, such as
200 mm or 300 mm diameter wafers, as well as, rectangular or square
panes. Unless otherwise noted, embodiments and examples described
herein are preferably conducted on substrates with a 200 mm
diameter or a 300 mm diameter, more preferably, a 300 mm diameter.
Processes of the embodiments described herein deposit ruthenium
materials on many substrates and surfaces. Substrates on which
embodiments of the invention may be useful include, but are not
limited to semiconductor wafers, such as crystalline silicon (e.g.,
Si<100> or Si<111>), silicon oxide, strained silicon,
silicon germanium, doped or undoped polysilicon, doped or undoped
silicon wafers and patterned or non-patterned wafers. Substrates
may be exposed to a pretreatment process to polish, etch, reduce,
oxidize, hydroxylate, anneal and/or bake the substrate surface.
[0175] "Atomic layer deposition" (ALD) or "cyclical deposition" as
used herein refers to the sequential introduction of two or more
reactive compounds to deposit a layer of material on a substrate
surface. The two, three or more reactive compounds may
alternatively be introduced into a reaction zone or process region
of a process chamber. The reactive compounds may be in a state of
gas, plasma, vapor, fluid or other state of matter useful for a
vapor deposition process. Usually, each reactive compound is
separated by a time delay to allow each compound to adhere and/or
react on the substrate surface. In one aspect, a first precursor or
compound A is pulsed into the reaction zone followed by a first
time delay. Next, a second precursor or compound B is pulsed into
the reaction zone followed by a second delay. Compound A and
compound B react to form a deposited material. During each time
delay a purge gas is introduced into the process chamber to purge
the reaction zone or otherwise remove any residual reactive
compound or by-products from the reaction zone. Alternatively, the
purge gas may flow continuously throughout the deposition process
so that only the purge gas flows during the time delay between
pulses of reactive compounds. The reactive compounds are
alternatively pulsed until a desired film thickness of the
deposited material is formed on the substrate surface. In either
scenario, the ALD process of pulsing compound A, purge gas, pulsing
compound B and purge gas is a cycle. A cycle can start with either
compound A or compound B and continue the respective order of the
cycle until achieving a film with the desired thickness. In another
embodiment, a first precursor containing compound A, a second
precursor containing compound B and a third precursor containing
compound C are each separately pulsed into the process chamber.
Alternatively, a pulse of a first precursor may overlap in time
with a pulse of a second precursor while a pulse of a third
precursor does not overlap in time with either pulse of the first
and second precursors. "Process gas" as used herein refers to a
single gas, multiple gases, a gas containing a plasma, combinations
of gas(es) and/or plasma(s). A process gas may contain at least one
reactive compound for a vapor deposition process. The reactive
compounds may be in a state of gas, plasma, vapor, fluid or other
state of matter useful for a vapor deposition process. Also, a
process may contain a purge gas or a carrier gas and not contain a
reactive compound.
Experiments
[0176] The experiments in this section were conducted on substrates
initially prepared by thermally growing a silicon dioxide layer
with a thickness of 3,000 .ANG.. Subsequently, a tantalum nitride
layer was deposited by an ALD process with a thickness of 10 .ANG..
A full description of the deposition techniques are further
discussed in commonly assigned U.S. Pat. No. 6,951,804, which is
incorporated herein in its entirety by reference. The tantalum
nitride film is a dielectric with a sheet resistance greater than
about 20,000 .OMEGA./sq.
[0177] The ALD experiments were completed in an ALD chamber, as
described above, available from Applied Materials, Inc., located in
Santa Clara, Calif. The chamber spacing (distance between the wafer
and the top of chamber body) was 230 mils (5.84 mm).
[0178] Experiment 1: (DMPD).sub.2Ru with constant flow of NH.sub.3
and intermediate plasma--The ruthenium precursor used during this
experiment was bis(2,4-dimethylpentadienyl) ruthenium
((DMPD).sub.2Ru). During the experiment, the pressure within the
process chamber was maintained at about 2 Torr and the substrate
was heated to about 300.degree. C. An ALD cycle included the
following steps. A ruthenium precursor gas was formed by passing a
nitrogen carrier gas with a flow rate of about 500 sccm through an
ampoule of (DMPD).sub.2Ru heated at a temperature of about
80.degree. C. The substrate was exposed to the ruthenium precursor
gas with a flow rate of about 500 sccm and ammonia gas with a flow
rate of about 1,500 sccm for about 3 seconds. The flow of the
ruthenium precursor gas was stopped while the flow of the ammonia
gas was maintained during a purge step. The purge step was
conducted for about 2 seconds. Subsequently, a plasma was ignited
to form an ammonia plasma from the ammonia gas while maintaining
the flow rate. The RF generator, having the power output set to
about 125 watts at 13.56 MHz, produced the plasma for about 4
seconds during the plasma step. Thereafter, the plasma power was
turned off and the chamber was exposed to a second purge step of
the ammonia gas with a constant flow rate for about 2 seconds. The
deposition process was stopped after the repetition of about 140
ALD cycles. A layer of ruthenium material was deposited on the
substrate with a thickness of about 5 .ANG.. The data from the
experiment was analyzed to determine no existence of a nucleation
delay and the average deposition rate was about 0.22
.ANG./cycle.
[0179] Experiment 2: (MeCp)(EtCp)Ru with constant flow of NH.sub.3
and intermediate plasma--The ruthenium precursor used during this
experiment was methylcyclopentadienyl ethylcyclopentadienyl
ruthenium ((MeCp)(EtCp)Ru). During the experiment, the pressure
within the process chamber was maintained at about 2 Torr and the
substrate was heated to about 300.degree. C. An ALD cycle included
the following steps. A ruthenium precursor gas was formed by
passing a nitrogen carrier gas with a flow rate of about 500 sccm
through an ampoule of (MeCp)(EtCp)Ru heated at a temperature of
about 80.degree. C. The substrate was exposed to the ruthenium
precursor gas with a flow rate of about 500 sccm and ammonia gas
with a flow rate of about 1,500 sccm for about 3 seconds. The flow
of the ruthenium precursor gas was stopped while the flow of the
ammonia gas was maintained during a purge step. The purge step was
conducted for about 2 seconds. Subsequently, a plasma was ignited
to form an ammonia plasma from the ammonia gas while maintaining
the flow rate. The RF generator, having the power output set to
about 125 watts at 13.56 MHz, produced the plasma for about 4
seconds during the plasma step. Thereafter, the plasma power was
turned off and the chamber was exposed to a second purge step of
the ammonia gas with a constant flow rate for about 2 seconds. The
deposition process was stopped after the repetition of about 140
ALD cycles. A layer of ruthenium material was deposited on the
substrate with a thickness of about 6 .ANG.. The data from the
experiment was analyzed to determine the existence of a nucleation
delay.
[0180] Experiment 3: (MeCp)(Pv)Ru with constant flow of NH.sub.3
and intermediate plasma--The ruthenium precursor used during this
experiment was methylcyclopentadienyl pyrrolyl ruthenium
((MeCp)(Py)Ru). During the experiment, the pressure within the
process chamber was maintained at about 2 Torr and the substrate
was heated to about 300.degree. C. An ALD cycle included the
following steps. A ruthenium precursor gas was formed by passing a
nitrogen carrier gas with a flow rate of about 500 sccm through an
ampoule of (MeCp)(Py)Ru heated at a temperature of about 80.degree.
C. The substrate was exposed to the ruthenium precursor gas with a
flow rate of about 500 sccm and ammonia gas with a flow rate of
about 1,500 sccm for about 3 seconds. The flow of the ruthenium
precursor gas was stopped while the flow of the ammonia gas was
maintained during a purge step. The purge step was conducted for
about 2 seconds. Subsequently, a plasma was ignited to form an
ammonia plasma from the ammonia gas while maintaining the flow
rate. The RF generator, having the power output set to about 300
watts at 13.56 MHz, produced the plasma for about 4 seconds during
the plasma step. Thereafter, the plasma power was turned off and
the chamber was exposed to a second purge step of the ammonia gas
with a constant flow rate for about 2 seconds. The deposition
process was stopped after the repetition of about 140 ALD cycles. A
layer of ruthenium material was deposited on the substrate with a
thickness of about 49 .ANG.. The data from the experiment was
analyzed to determine no existence of a nucleation delay and the
average deposition rate was about 0.35 .ANG./cycle.
[0181] Experiment 4: (MeCp)(Pv)Ru with constant flow of N.sub.2 and
intermediate plasma--During the experiment, the pressure within the
process chamber was maintained at about 4 Torr and the substrate
was heated to about 350.degree. C. An ALD cycle included the
following steps. A ruthenium precursor gas was formed by passing a
nitrogen carrier gas with a flow rate of about 500 sccm through an
ampoule of (MeCp)(Py)Ru heated at a temperature of about 80.degree.
C. The substrate was exposed to the ruthenium precursor gas with a
flow rate of about 500 sccm and nitrogen gas with a flow rate of
about 1,500 sccm for about 3 seconds. The flow of the ruthenium
precursor gas was stopped while the flow of the nitrogen gas was
maintained during a purge step. The purge step was conducted for
about 2 seconds. Subsequently, a plasma was ignited to form a
nitrogen plasma from the nitrogen gas while maintaining the flow
rate. The RF generator, having the power output set to about 500
watts at 13.56 MHz, produced the plasma for about 4 seconds during
the plasma step. Thereafter, the plasma power was turned off and
the chamber was exposed to a second purge step of the nitrogen gas
with a constant flow rate for about 2 seconds. The deposition
process was stopped after the repetition of about 140 ALD cycles. A
layer of ruthenium material was deposited on the substrate with a
thickness of about 46 .ANG.. The data from the experiment was
analyzed to determine no existence of a nucleation delay and the
average deposition rate was about 0.33 .ANG./cycle.
[0182] Experiment 5: (MeCp)(Pv)Ru with constant flow of H.sub.2 and
intermediate plasma--During the experiment, the pressure within the
process chamber was maintained at about 4 Torr and the substrate
was heated to about 350.degree. C. An ALD cycle included the
following steps. A ruthenium precursor gas was formed by passing a
nitrogen carrier gas with a flow rate of about 500 sccm through an
ampoule of (MeCp)(Py)Ru heated at a temperature of about 80.degree.
C. The substrate was exposed to the ruthenium precursor gas with a
flow rate of about 500 sccm and hydrogen gas with a flow rate of
about 1,500 sccm for about 3 seconds. The flow of the ruthenium
precursor gas was stopped while the flow of the hydrogen gas was
maintained during a purge step. The purge step was conducted for
about 2 seconds. Subsequently, a plasma was ignited to form a
hydrogen plasma from the hydrogen gas while maintaining the flow
rate. The RF generator, having the power output set to about 500
watts at 13.56 MHz, produced the plasma for about 4 seconds during
the plasma step. Thereafter, the plasma power was turned off and
the chamber was exposed to a second purge step of the hydrogen gas
with a constant flow rate for about 2 seconds. The deposition
process was stopped after the repetition of about 140 ALD cycles. A
layer of ruthenium material was deposited on the substrate with a
thickness of about 45 .ANG.. The data from the experiment was
analyzed to determine no existence of a nucleation delay and the
average deposition rate was about 0.32 .ANG./cycle.
[0183] Experiment 6: (MeCp)(Pv)Ru with intermediate NH.sub.3
plasma--During the experiment, the pressure within the process
chamber was maintained at about 2 Torr and the substrate was heated
to about 300.degree. C. An ALD cycle included the following steps.
A ruthenium precursor gas was formed by passing a nitrogen carrier
gas with a flow rate of about 500 sccm through an ampoule of
(MeCp)(Py)Ru heated at a temperature of about 80.degree. C. The
substrate was exposed to the ruthenium precursor gas with a flow
rate of about 500 sccm for about 3 seconds. The flow of the
ruthenium precursor gas was stopped and a nitrogen purge gas with a
flow rate of about 500 sccm was administered into the chamber
during a purge step. The purge step was conducted for about 2
seconds. Thereafter, an ammonia gas with a flow rate of about 1,500
sccm was administered into the chamber after stopping the flow of
the nitrogen gas. Subsequently, a plasma was ignited to form an
ammonia plasma from the ammonia gas while maintaining the flow
rate. The RF generator, having the power output set to about 300
watts at 13.56 MHz, produced the plasma for about 4 seconds during
the plasma step. Thereafter, the flow of the ammonia gas and the
plasma power were turned off. The chamber was exposed to a second
purge step of nitrogen gas with a flow rate of about 500 sccm for
about 2 seconds. The deposition process was stopped after the
repetition of about 150 ALD cycles. A layer of ruthenium material
was deposited on the substrate with a thickness of about 51 .ANG..
The data from the experiment was analyzed to determine no existence
of a nucleation delay and the average deposition rate was about
0.34 .ANG./cycle.
[0184] Experiment 7: (MeCp)(Pv)Ru with intermediate N.sub.2
plasma--During the experiment, the pressure within the process
chamber was maintained at about 4 Torr and the substrate was heated
to about 350.degree. C. An ALD cycle included the following steps.
A ruthenium precursor gas was formed by passing a nitrogen carrier
gas with a flow rate of about 500 sccm through an ampoule of
(MeCp)(Py)Ru heated at a temperature of about 80.degree. C. The
substrate was exposed to the ruthenium precursor gas with a flow
rate of about 500 sccm for about 3 seconds. The flow of the
ruthenium precursor gas was stopped and a nitrogen purge gas with a
flow rate of about 500 sccm was administered into the chamber
during a purge step. The purge step was conducted for about 2
seconds. Subsequently, a plasma was ignited to form a nitrogen
plasma from the nitrogen gas while maintaining the flow rate. The
RF generator, having the power output set to about 500 watts at
13.56 MHz, produced the plasma for about 4 seconds during the
plasma step. Thereafter, the flow of the nitrogen gas and the
plasma power were turned off. The chamber was exposed to a second
purge step of nitrogen gas with a flow rate of about 500 sccm for
about 2 seconds. The deposition process was stopped after the
repetition of about 150 ALD cycles. A layer of ruthenium material
was deposited on the substrate with a thickness of about 50 .ANG..
The data from the experiment was analyzed to determine no existence
of a nucleation delay and the average deposition rate was about
0.33 .ANG./cycle.
[0185] Experiment 8: (MeCp)(Pv)Ru with intermediate H.sub.2
plasma--During the experiment, the pressure within the process
chamber was maintained at about 4 Torr and the substrate was heated
to about 350.degree. C. An ALD cycle included the following steps.
A ruthenium precursor gas was formed by passing a nitrogen carrier
gas with a flow rate of about 500 sccm through an ampoule of
(MeCp)(Py)Ru heated at a temperature of about 80.degree. C. The
substrate was exposed to the ruthenium precursor gas with a flow
rate of about 500 sccm for about 3 seconds. The flow of the
ruthenium precursor gas was stopped and a nitrogen purge gas with a
flow rate of about 500 sccm was administered into the chamber
during a purge step. The purge step was conducted for about 2
seconds. Thereafter, a hydrogen gas with a flow rate of about 1,500
sccm was administered into the chamber after stopping the flow of
the nitrogen gas. Subsequently, a plasma was ignited to form a
hydrogen plasma from the hydrogen gas while maintaining the flow
rate. The RF generator, having the power output set to about 500
watts at 13.56 MHz, produced the plasma for about 4 seconds during
the plasma step. Thereafter, the flow of the hydrogen gas and the
plasma power were turned off. The chamber was exposed to a second
purge step of nitrogen gas with a flow rate of about 500 sccm for
about 2 seconds. The deposition process was stopped after the
repetition of about 150 ALD cycles. A layer of ruthenium material
was deposited on the substrate with a thickness of about 48 .ANG..
The data from the experiment was analyzed to determine no existence
of a nucleation delay and the average deposition rate was about
0.32 .ANG./cycle.
Other ALD Process
[0186] Embodiments of the invention provide methods for depositing
a variety of metal-containing materials (e.g., tantalum or tungsten
containing materials) on a substrate by a thermal ALD process or a
PE-ALD process by utilizing process chamber 50 or lid assembly 100.
In one example, tantalum nitride is deposited by sequentially
exposing a substrate to a tantalum precursor and a plasma during a
PE-ALD process. In another example, tungsten nitride is deposited
by sequentially exposing a substrate to a tungsten precursor and a
plasma during a PE-ALD process. In other examples, metallic
tantalum or metallic tungsten is deposited by sequentially exposing
a substrate to a tantalum precursor or a tungsten precursor and a
plasma during a PE-ALD process.
[0187] Tantalum precursors useful during vapor deposition processes
as described herein include pentakis(dimethylamido) tantalum (PDMAT
or Ta(NMe.sub.2).sub.5), pentakis(ethylmethylamido) tantalum (PEMAT
or Ta[N(Et)Me].sub.5), pentakis(diethylamido) tantalum (PDEAT or
Ta(NEt.sub.2).sub.5,), ethylimido-tris(dimethylamido) tantalum
((EtN)Ta(NMe.sub.2).sub.3), ethylimido-tris(diethylamido) tantalum
((EtN)Ta(NEt.sub.2).sub.3), ethylimido-tris(ethylmethylamido)
tantalum ((EtN)Ta[N(Et)Me].sub.3),
tertiarybutylimido-tris(dimethylamido) tantalum (TBTDMT or
(.sup.tBuN)Ta(NMe.sub.2).sub.3),
tertiarybutylimido-tris(diethylamido) tantalum (TBTDET or
(.sup.tBuN)Ta(NEt.sub.2).sub.3),
tertiarybutylimido-tris(ethylmethylamido) tantalum (TBTEAT or
(.sup.tBuN)Ta[N(Et)Me].sub.3),
tertiaryamylimido-tris(dimethylamido) tantalum (TAIMATA or
(.sup.tAmyIN)Ta(NMe.sub.2).sub.3, wherein .sup.tAmyl is the
tertiaryamyl group (C.sub.5H.sub.11-- or
CH.sub.3CH.sub.2C(CH.sub.3).sub.2--),
tertiaryamylimido-tris(diethylamido) tantalum (TAIEATA or
(.sup.tAmyIN)Ta(NEt.sub.2).sub.3,
tertiaryamylimido-tris(ethylmethylamido) tantalum (TAIMATA or
(.sup.tAmyIN)Ta([N(Et)Me].sub.3), tantalum halides (e.g., TaF.sub.5
or TaCl.sub.5), derivatives thereof, or combinations thereof.
[0188] Tungsten precursors that may be useful during the vapor
deposition processes as described herein include
bis(tertiarybutylimido) bis(tertiarybutylamido) tungsten
((.sup.tBuN).sub.2W(N(H)tBu).sub.2), bis(tertiarybutylimido)
bis(dimethylamido) tungsten ((.sup.tBuN).sub.2W(NMe.sub.2).sub.2),
bis(tertiarybutylimido) bis(diethylamido) tungsten
((.sup.tBuN).sub.2W(NEt.sub.2).sub.2), bis(tertiarybutylimido)
bis(ethylmethylamido) tungsten ((.sup.tBuN).sub.2W(NEtMe).sub.2),
tungsten hexafluoride, derivatives thereof, or combinations
thereof.
[0189] Nitrogen precursors that may be useful for forming a
metal-containing material during the vapor deposition processes as
described herein include ammonia (NH.sub.3), hydrazine
(N.sub.2H.sub.4), methylhydrazine (Me(H)NNH.sub.2), dimethyl
hydrazine (Me.sub.2NNH.sub.2 or Me(H)NN(H)Me),
tertiarybutylhydrazine (tBu(H)NNH.sub.2), phenylhydrazine
(C.sub.6H.sub.5(H)NNH.sub.2), a nitrogen plasma source (e.g.,
N,N.sub.2, N.sub.2/H.sub.2, NH.sub.3, or a N.sub.2H.sub.4 plasma),
2,2'-azotertbutane (.sup.tBuNN.sup.tBu), an azide source, such as
ethyl azide (EtN.sub.3), trimethylsilyl azide (Me.sub.3SiN.sub.3),
derivatives thereof, plasmas thereof, or combinations thereof.
[0190] A suitable reagent for forming a metal-containing material
may be a reducing gas and include hydrogen (e.g., H.sub.2 or
atomic-H), atomic-N, ammonia (NH.sub.3), hydrazine
(N.sub.2H.sub.4), silane (SiH.sub.4), disilane (Si.sub.2H.sub.6),
trisilane (Si.sub.3H.sub.8), tetrasilane (Si.sub.4H.sub.10),
dimethylsilane (SiC.sub.2H.sub.8), methyl silane (SiCH.sub.6),
ethylsilane (SiC.sub.2H.sub.8), chlorosilane (ClSiH.sub.3),
dichlorosilane (Cl.sub.2SiH.sub.2), hexachlorodisilane
(Si.sub.2Cl.sub.6), borane (BH.sub.3), diborane (B.sub.2H.sub.6),
triborane, tetraborane, pentaborane, triethylborane (Et.sub.3B),
derivatives thereof, plasmas thereof, or combinations thereof.
[0191] A carrier gas, a purge gas and a process gas may contain
nitrogen, hydrogen, ammonia, argon, neon, helium, or combinations
thereof. A plasma may be ignited containing any of these gases.
Preferably, a plasma precursor gas that may be useful for forming a
metal-containing material during the vapor deposition processes as
described herein include nitrogen, hydrogen, ammonia, argon or
combinations thereof. In one example, a plasma contains nitrogen
and hydrogen. In another example, a plasma contains nitrogen and
ammonia. In another example, a plasma contains ammonia and
hydrogen.
[0192] Metal-containing materials that may be formed during thermal
ALD or PE-ALD processes as described herein include tantalum,
tantalum nitride, tungsten, tungsten nitride, titanium, titanium
nitride, alloys thereof, derivatives thereof or combinations
thereof. In one embodiment, a metal-containing material may be
formed during a PE-ALD process containing a constant flow of a
reagent gas while providing sequential pulses of a metal precursor
and a plasma. In another embodiment, a metal-containing material
may be formed during another PE-ALD process that provides
sequential pulses of a metal precursor and a reagent plasma. In
both of these embodiments, the reagent is generally ionized during
the process. Also, the PE-ALD process provides that the plasma may
be generated external from the process chamber, such as by a remote
plasma generator (RPS) system, or preferably, the plasma may be
generated in situ a plasma capable ALD process chamber. During
PE-ALD processes, a plasma may be generated from a microwave (MW)
frequency generator or a radio frequency (RF) generator. For
example, a plasma may be ignited within process chamber 50 or with
lid assembly 100. In a preferred example, an in situ plasma is
generated by a RF generator. In another embodiment, a
metal-containing material may be formed during a thermal ALD
process that provides sequential pulses of a metal precursor and a
reagent.
[0193] The ALD process provides that the process chamber may be
pressurized at a pressure within a range from about 0.1 Torr to
about 80 Torr, preferably from about 0.5 Torr to about 10 Torr, and
more preferably, from about 1 to about 5. Also, the chamber or the
substrate may be heated to a temperature of less than about
500.degree. C., preferably within a range from about 100.degree. C.
to about 450.degree. C., and more preferably, from about
150.degree. C. to about 400.degree. C., for example, about
300.degree. C. During PE-ALD processes, a plasma is ignited within
the process chamber for an in situ plasma process, or alternative,
may be formed by an external source, such as a remote plasma
generator (RPS) system. A plasma may be generated a MW generator,
but preferably by a RF generator. For example, a plasma may be
ignited within process chamber 50 or with lid assembly 100. The RF
generator may be set at a frequency within a range from about 100
KHz to about 1.6 MHz. In one example, a RF generator, with a
frequency of 13.56 MHz, may be set to have a power output within a
range from about 100 watts to about 1,000 watts, preferably, from
about 250 watts to about 600 watts, and more preferably, from about
300 watts to about 500 watts. In one example, a RF generator, with
a frequency of 400 KHz, may be set to have a power output within a
range from about 200 watts to about 2,000 watts, preferably, from
about 500 watts to about 1,500 watts. A surface of substrate may be
exposed to a plasma having a power per surface area value within a
range from about 0.01 watts/cm.sup.2 to about 10.0 watts/cm.sup.2,
preferably, from about 0.05 watts/cm.sup.2 to about 6.0
watts/cm.sup.2.
[0194] The substrate may be for example, a silicon substrate having
an interconnect pattern defined in one or more dielectric material
layers formed thereon. In example, the substrate contains a barrier
layer thereon, while in another example, the substrate contains a
dielectric surface. The process chamber conditions such as, the
temperature and pressure, are adjusted to enhance the adsorption of
the process gases on the substrate so as to facilitate the reaction
of the pyrrolyl metal precursors and the reagent gas.
[0195] In one embodiment, the substrate may be exposed to a reagent
gas throughout the whole ALD cycle. The substrate may be exposed to
a metal precursor gas formed by passing a carrier gas (e.g.,
nitrogen or argon) through an ampoule of a metal precursor. The
ampoule may be heated depending on the metal precursor used during
the process. In one example, an ampoule containing (MeCp)(Py)Ru may
be heated to a temperature within a range from about 60.degree. C.
to about 100.degree. C., such as 80.degree. C. The metal precursor
gas usually has a flow rate within a range from about 100 sccm to
about 2,000 sccm, preferably, from about 200 sccm to about 1,000
sccm, and more preferably, from about 300 sccm to about 700 sccm,
for example, about 500 sccm. The metal precursor gas and the
reagent gas may be combined to form a deposition gas. A reagent gas
usually has a flow rate within a range from about 100 sccm to about
3,000 sccm, preferably, from about 200 sccm to about 2,000 sccm,
and more preferably, from about 500 sccm to about 1,500 sccm. In
one example, ammonia is used as a reagent gas with a flow rate of
about 1,500 sccm. The substrate may be exposed to the metal
precursor gas or the deposition gas containing the metal precursor
and the reagent gas for a time period within a range from about 0.1
seconds to about 8 seconds, preferably, from about 1 second to
about 5 seconds, and more preferably, from about 2 seconds to about
4 seconds. The flow of the metal precursor gas may be stopped once
the metal precursor is adsorbed on the substrate. The metal
precursor may be a discontinuous layer, continuous layer or even
multiple layers.
[0196] The substrate and chamber may be exposed to a purge step
after stopping the flow of the metal precursor gas. The flow rate
of the reagent gas may be maintained or adjusted from the previous
step during the purge step. Preferably, the flow of the reagent gas
is maintained from the previous step. Optionally, a purge gas may
be administered into the process chamber with a flow rate within a
range from about 100 sccm to about 2,000 sccm, preferably, from
about 200 sccm to about 1,000 sccm, and more preferably, from about
300 sccm to about 700 sccm, for example, about 500 sccm. The purge
step removes any excess metal precursor and other contaminants
within the process chamber. The purge step may be conducted for a
time period within a range from about 0.1 seconds to about 8
seconds, preferably, from about 1 second to about 5 seconds, and
more preferably, from about 2 seconds to about 4 seconds. The
carrier gas, the purge gas and the process gas may contain
nitrogen, hydrogen, ammonia, argon, neon, helium, or combinations
thereof. In a preferred embodiment, the carrier gas contains
nitrogen.
[0197] Thereafter, the flow of the reagent gas may be maintained or
adjusted before igniting a plasma. The substrate may be exposed to
the plasma for a time period within a range from about 0.1 seconds
to about 20 seconds, preferably, from about 1 second to about 10
seconds, and more preferably, from about 2 seconds to about 8
seconds. Thereafter, the plasma power was turned off. In one
example, the reagent may be ammonia, nitrogen, hydrogen or a
combination thereof to form an ammonia plasma, a nitrogen plasma, a
hydrogen plasma or a combined plasma. The reactant plasma reacts
with the adsorbed metal precursor on the substrate to form a
metal-containing material thereon. In one example, the reactant
plasma is used as a reductant to form metallic ruthenium, tantalum,
tungsten, titanium or alloys thereof. However, a variety of
reactants may be used to form metal-containing materials having a
wide range of compositions. In one example, a boron-containing
reactant compound (e.g., diborane) is used to form a
metal-containing material containing boride. In another example, a
silicon-containing reactant compound (e.g., silane) is used to form
a metal-containing material containing silicide.
[0198] The process chamber was exposed to a second purge step to
remove excess precursors or contaminants from the previous step.
The flow rate of the reagent gas may be maintained or adjusted from
the previous step during the purge step. An optional purge gas may
be administered into the process chamber with a flow rate within a
range from about 100 sccm to about 2,000 sccm, preferably, from
about 200 sccm to about 1,000 sccm, and more preferably, from about
300 sccm to about 700 sccm, for example, about 500 sccm. The second
purge step may be conducted for a time period within a range from
about 0.1 seconds to about 8 seconds, preferably, from about 1
second to about 5 seconds, and more preferably, from about 2
seconds to about 4 seconds.
[0199] The ALD cycle may be repeated until a predetermined
thickness of the metal-containing material is deposited on the
substrate. The metal-containing material may be deposited with a
thickness less than 1,000 .ANG., preferably less than 500 .ANG. and
more preferably from about 10 .ANG. to about 100 .ANG., for
example, about 30 .ANG.. The processes as described herein may
deposit a metal-containing material at a rate of at least 0.15
.ANG./cycle, preferably, at least 0.25 .ANG./cycle, more
preferably, at least 0.35 .ANG./cycle or faster. In another
embodiment, the processes as described herein overcome shortcomings
of the prior art relative as related to nucleation delay. There is
no detectable nucleation delay during many, if not most, of the
experiments to deposit the metal-containing materials.
[0200] In another embodiment, a metal-containing material may be
formed during another PE-ALD process that provides sequentially
exposing the substrate to pulses of a metal precursor and an active
reagent, such as a reagent plasma. The substrate may be exposed to
a metal precursor gas formed by passing a carrier gas through an
ampoule containing a metal precursor, as described herein. The
metal precursor gas usually has a flow rate within a range from
about 100 sccm to about 2,000 sccm, preferably, from about 200 sccm
to about 1,000 sccm, and more preferably, from about 300 sccm to
about 700 sccm, for example, about 500 sccm. The substrate may be
exposed to the deposition gas containing the metal precursor and
the reagent gas for a time period within a range from about 0.1
seconds to about 8 seconds, preferably, from about 1 second to
about 5 seconds, and more preferably from about 2 seconds to about
4 seconds. The flow of the metal precursor gas may be stopped once
the metal precursor is adsorbed on the substrate. The metal
precursor may be a discontinuous layer, continuous layer or even
multiple layers.
[0201] Subsequently, the substrate and chamber are exposed to a
purge step. A purge gas may be administered into the process
chamber during the purge step. In one aspect, the purge gas is the
reagent gas, such as ammonia, nitrogen or hydrogen. In another
aspect, the purge gas may be a different gas than the reagent gas.
For example, the reagent gas may be ammonia and the purge gas may
be nitrogen, hydrogen or argon. The purge gas may have a flow rate
within a range from about 100 sccm to about 2,000 sccm, preferably,
from about 200 sccm to about 1,000 sccm, and more preferably, from
about 300 sccm to about 700 sccm, for example, about 500 sccm. The
purge step removes any excess metal precursor and other
contaminants within the process chamber. The purge step may be
conducted for a time period within a range from about 0.1 seconds
to about 8 seconds, preferably, from about 1 second to about 5
seconds, and more preferably, from about 2 seconds to about 4
seconds. A carrier gas, a purge gas and a process gas may contain
nitrogen, hydrogen, ammonia, argon, neon, helium or combinations
thereof.
[0202] The substrate and the adsorbed metal precursor thereon may
be exposed to the reagent gas during the next step of the ALD
process. Optionally, a carrier gas may be administered at the same
time as the reagent gas into the process chamber. The reagent gas
may be ignited to form a plasma. The reagent gas usually has a flow
rate within a range from about 100 sccm to about 3,000 sccm,
preferably, from about 200 sccm to about 2,000 sccm, and more
preferably, from about 500 sccm to about 1,500 sccm. In one
example, ammonia is used as a reagent gas with a flow rate of about
1,500 sccm. The substrate may be exposed to the plasma for a time
period within a range from about 0.1 seconds to about 20 seconds,
preferably, from about 1 second to about 10 seconds, and more
preferably, from about 2 seconds to about 8 seconds. Thereafter,
the plasma power may be turned off. In one example, the reagent may
be ammonia, nitrogen, hydrogen or combinations thereof, while the
plasma may be an ammonia plasma, a nitrogen plasma, a hydrogen
plasma or a combination thereof. The reactant plasma reacts with
the adsorbed metal precursor on the substrate to form a
metal-containing material thereon. Preferably, the reactant plasma
is used as a reductant to form metallic ruthenium, tantalum,
tungsten, titanium or alloys thereof. However, a variety of
reactants may be used to form metal-containing materials having a
wide range of compositions, as described herein.
[0203] The process chamber may be exposed to a second purge step to
remove excess precursors or contaminants from the process chamber.
The flow of the reagent gas may have been stopped at the end of the
previous step and started during the purge step, if the reagent gas
is used as a purge gas. Alternative, a purge gas that is different
than the reagent gas may be administered into the process chamber.
The reagent gas or purge gas may have a flow rate within a range
from about 100 sccm to about 2,000 sccm, preferably, from about 200
sccm to about 1,000 sccm, and more preferably, from about 300 sccm
to about 700 sccm, for example, about 500 sccm. The second purge
step may be conducted for a time period within a range from about
0.1 seconds to about 8 seconds, preferably, from about 1 second to
about 5 seconds, and more preferably, from about 2 seconds to about
4 seconds.
[0204] The ALD cycle may be repeated until a predetermined
thickness of the metal-containing material is deposited on the
substrate. The metal-containing material may be deposited with a
thickness less than 1,000 .ANG., preferably less than 500 .ANG. and
more preferably from about 10 .ANG. to about 100 .ANG., for
example, about 30 .ANG.. The processes as described herein may
deposit a metal-containing material at a rate of at least 0.15
.ANG./cycle, preferably, at least 0.25 .ANG./cycle, more
preferably, at least 0.35 .ANG./cycle or faster. In another
embodiment, the processes as described herein overcome shortcomings
of the prior art relative as related to nucleation delay. There is
no detectable nucleation delay during many, if not most, of the
experiments to deposit the metal-containing materials.
[0205] The time interval for the pulse of the metal precursor is
variable depending upon a number of factors such as, for example,
the volume capacity of the process chamber employed, the vacuum
system coupled thereto and the volatility/reactivity of the
reactants used during the ALD process. For example, (1) a
large-volume process chamber may lead to a longer time to stabilize
the process conditions such as, for example, carrier/purge gas flow
and temperature, requiring a longer pulse time; (2) a lower flow
rate for the process gas may also lead to a longer time to
stabilize the process conditions requiring a longer pulse time; and
(3) a lower chamber pressure means that the process gas is
evacuated from the process chamber more quickly requiring a longer
pulse time. In general, the process conditions are advantageously
selected so that a pulse of the metal precursor provides a
sufficient amount of precursor so that at least a monolayer of the
metal precursor is adsorbed on the substrate. Thereafter, excess
metal precursor remaining in the chamber may be removed from the
process chamber by the constant carrier gas stream in combination
with the vacuum system.
[0206] The time interval for each of the pulses of the metal
precursor and the reagent gas may have the same duration. That is,
the duration of the pulse of the metal precursor may be identical
to the duration of the pulse of the reagent gas. For such an
embodiment, a time interval (T.sub.1) for the pulse of the metal
precursor is equal to a time interval (T.sub.2) for the pulse of
the reagent gas.
[0207] Alternatively, the time interval for each of the pulses of
the metal precursor and the reagent gas may have different
durations. That is, the duration of the pulse of the metal
precursor may be shorter or longer than the duration of the pulse
of the reagent gas. For such an embodiment, a time interval
(T.sub.1) for the pulse of the metal precursor is different than
the time interval (T.sub.2) for the pulse of the reagent gas.
[0208] In addition, the periods of non-pulsing between each of the
pulses of the metal precursor and the reagent gas may have the same
duration. That is, the duration of the period of non-pulsing
between each pulse of the metal precursor and each pulse of the
reagent gas is identical. For such an embodiment, a time interval
(T.sub.3) of non-pulsing between the pulse of the metal precursor
and the pulse of the reagent gas is equal to a time interval
(T.sub.4) of non-pulsing between the pulse of the reagent gas and
the pulse of the metal precursor. During the time periods of
non-pulsing only the constant carrier gas stream is provided to the
process chamber.
[0209] Alternatively, the periods of non-pulsing between each of
the pulses of the metal precursor and the reagent gas may have
different duration. That is, the duration of the period of
non-pulsing between each pulse of the metal precursor and each
pulse of the reagent gas may be shorter or longer than the duration
of the period of non-pulsing between each pulse of the reagent gas
and the metal precursor. For such an embodiment, a time interval
(T.sub.3) of non-pulsing between the pulse of the metal precursor
and the pulse of the reagent gas is different from a time interval
(T.sub.4) of non-pulsing between the pulse of the reagent gas and
the pulse of metal precursor. During the time periods of
non-pulsing only the constant carrier gas stream is provided to the
process chamber.
[0210] Additionally, the time intervals for each pulse of the metal
precursor, the reagent gas and the periods of non-pulsing
therebetween for each deposition cycle may have the same duration.
For such an embodiment, a time interval (T.sub.1) for the metal
precursor, a time interval (T.sub.2) for the reagent gas, a time
interval (T.sub.3) of non-pulsing between the pulse of the metal
precursor and the pulse of the reagent gas and a time interval
(T.sub.4) of non-pulsing between the pulse of the reagent gas and
the pulse of the metal precursor each have the same value for each
deposition cycle. For example, in a first deposition cycle
(C.sub.1), a time interval (T.sub.1) for the pulse of the metal
precursor has the same duration as the time interval (T.sub.1) for
the pulse of the metal precursor in subsequent deposition cycles
(C.sub.2 . . . C.sub.n). Similarly, the duration of each pulse of
the reagent gas and the periods of non-pulsing between the pulse of
the metal precursor and the reagent gas in the first deposition
cycle (C.sub.1) is the same as the duration of each pulse of the
reagent gas and the periods of non-pulsing between the pulse of the
metal precursor and the reagent gas in subsequent deposition cycles
(C.sub.2 . . . C.sub.n), respectively.
[0211] Alternatively, the time intervals for at least one pulse of
the metal precursor, the reagent gas and the periods of non-pulsing
therebetween for one or more of the deposition cycles of the
metal-containing material deposition process may have different
durations. For such an embodiment, one or more of the time
intervals (T.sub.1) for the pulses of the metal precursor, the time
intervals (T.sub.2) for the pulses of the reagent gas, the time
intervals (T.sub.3) of non-pulsing between the pulse of the metal
precursor and the reagent gas and the time intervals (T.sub.4) of
non-pulsing between the pulses of the reagent gas and the metal
precursor may have different values for one or more deposition
cycles of the cyclical deposition process. For example, in a first
deposition cycle (C.sub.1), the time interval (T.sub.1) for the
pulse of the metal precursor may be longer or shorter than one or
more time interval (T.sub.1) for the pulse of the metal precursor
in subsequent deposition cycles (C.sub.2 . . . C.sub.n). Similarly,
the durations of the pulses of the reagent gas and the periods of
non-pulsing between the pulse of the metal precursor and the
reagent gas in the first deposition cycle (C.sub.1) may be the same
or different than the duration of each pulse of the reagent gas and
the periods of non-pulsing between the pulse of the metal precursor
and the reagent gas in subsequent deposition cycles (C.sub.2 . . .
C.sub.n).
[0212] In some embodiments, a constant flow of a carrier gas or a
purge gas may be provided to the process chamber modulated by
alternating periods of pulsing and non-pulsing where the periods of
pulsing alternate between the metal precursor and the reagent gas
along with the carrier/purge gas stream, while the periods of
non-pulsing include only the carrier/purge gas stream.
[0213] While foregoing is directed to the preferred embodiment of
the invention, other and further embodiments of the invention may
be devised without departing from the basic scope thereof, and the
scope thereof is determined by the claims that follow.
* * * * *