U.S. patent application number 12/021798 was filed with the patent office on 2008-08-28 for process for tungsten nitride deposition by a temperature controlled lid assembly.
Invention is credited to Yu Chang, Avgerinos V. Gelatos, Wing-Cheong Lai, Sang Q. Le, Sang-Hyeob Lee, Jing Lin, Emily Renuart, Gwo-Chuan Tzu, Salvador P. Umotoy, Xiaoxiong Yuan.
Application Number | 20080206987 12/021798 |
Document ID | / |
Family ID | 39714455 |
Filed Date | 2008-08-28 |
United States Patent
Application |
20080206987 |
Kind Code |
A1 |
Gelatos; Avgerinos V. ; et
al. |
August 28, 2008 |
PROCESS FOR TUNGSTEN NITRIDE DEPOSITION BY A TEMPERATURE CONTROLLED
LID ASSEMBLY
Abstract
Embodiments of the invention provide processes for vapor
depositing tungsten-containing materials, such as metallic tungsten
and tungsten nitride. In one embodiment, a method for forming a
tungsten-containing material is provided which includes positioning
a substrate within a processing chamber containing a lid plate,
heating the lid plate to a temperature within a range from about
120.degree. C. to about 180.degree. C., exposing the substrate to a
reducing gas during a pre-nucleation soak process, and depositing a
first tungsten nucleation layer on the substrate during a first
atomic layer deposition process within the processing chamber. The
method further provides depositing a tungsten nitride layer on the
first tungsten nucleation layer during a vapor deposition process,
depositing a second tungsten nucleation layer on the tungsten
nitride layer during a second atomic layer deposition process
within the processing chamber, and exposing the substrate to
another reducing gas during a post-nucleation soak process.
Inventors: |
Gelatos; Avgerinos V.;
(Redwood City, CA) ; Lee; Sang-Hyeob; (Fremont,
CA) ; Yuan; Xiaoxiong; (San Jose, CA) ;
Umotoy; Salvador P.; (Antioch, CA) ; Chang; Yu;
(San Jose, CA) ; Tzu; Gwo-Chuan; (Sunnyvale,
CA) ; Renuart; Emily; (Santa Clara, CA) ; Lin;
Jing; (Mountain View, CA) ; Lai; Wing-Cheong;
(Santa Clara, CA) ; Le; Sang Q.; (San Jose,
CA) |
Correspondence
Address: |
PATTERSON & SHERIDAN, LLP - - APPM/TX
3040 POST OAK BOULEVARD, SUITE 1500
HOUSTON
TX
77056
US
|
Family ID: |
39714455 |
Appl. No.: |
12/021798 |
Filed: |
January 29, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60887142 |
Jan 29, 2007 |
|
|
|
60944085 |
Jun 14, 2007 |
|
|
|
Current U.S.
Class: |
438/654 ;
257/E21.476 |
Current CPC
Class: |
C23C 16/34 20130101;
C23C 16/14 20130101; C23C 16/4411 20130101; C23C 16/45512 20130101;
C23C 16/45523 20130101; C23C 16/4401 20130101 |
Class at
Publication: |
438/654 ;
257/E21.476 |
International
Class: |
H01L 21/44 20060101
H01L021/44 |
Claims
1. A method for forming a tungsten-containing material on a
substrate, comprising: positioning a substrate within a processing
chamber comprising a lid plate; heating the lid plate to a
temperature within a range from about 120.degree. C. to about
180.degree. C.; depositing a tungsten nitride layer over the
substrate during a vapor deposition process within the processing
chamber; and depositing a tungsten nucleation layer over the
tungsten nitride layer during an atomic layer deposition process
within the processing chamber.
2. The method of claim 1, wherein the lid plate is heated by a
resistive heating element therein.
3. The method of claim 2, wherein the lid plate is heated to a
temperature within a range from about 140.degree. C. to about
160.degree. C.
4. The method of claim 3, wherein the temperature is within a range
from about 145.degree. C. to about 155.degree. C.
5. The method of claim 1, wherein the tungsten nitride layer is
deposited during a chemical vapor deposition process comprising
co-flowing a tungsten precursor and a nitrogen precursor, the
tungsten precursor comprises tungsten hexafluoride, and the
nitrogen precursor comprises ammonia.
6. The method of claim 1, further comprising depositing a tungsten
adhesion layer over the substrate prior to depositing the tungsten
nitride layer thereon.
7. The method of claim 6, wherein the tungsten adhesion layer is
deposited during an atomic layer deposition process within the
processing chamber.
8. The method of claim 6, further comprising exposing the substrate
to a reducing agent during a pre-soak process prior to depositing
the tungsten adhesion layer or the tungsten nucleation layer.
9. The method of claim 8, wherein the reducing agent is selected
from the group consisting of silane, hydrogen, diborane, disilane,
phosphine, derivatives thereof, and combinations thereof.
10. The method of claim 6, further comprising exposing the tungsten
adhesion layer or the tungsten nucleation layer to a reducing agent
during a post-soak process.
11. The method of claim 10, wherein the reducing agent is selected
from the group consisting of silane, hydrogen, diborane, disilane,
phosphine, derivatives thereof, and combinations thereof.
12. The method of claim 1, wherein a bulk tungsten layer is
deposited over the tungsten nucleation layer during a thermal
chemical vapor deposition process.
13. A method for forming a tungsten-containing material on a
substrate, comprising: positioning a substrate within a processing
chamber comprising a lid plate; heating the lid plate to a
temperature within a range from about 120.degree. C. to about
180.degree. C.; exposing the substrate to a reducing gas during a
pre-nucleation soak process; depositing a tungsten adhesion layer
over the substrate during a first vapor deposition process within
the processing chamber; depositing a tungsten nitride layer over
the tungsten adhesion layer during a second vapor deposition
process within the processing chamber; depositing a tungsten
nucleation layer over the tungsten nitride layer during a third
vapor deposition process within the processing chamber; exposing
the substrate to another reducing gas during a post-nucleation soak
process within the processing chamber; and depositing a tungsten
bulk layer over the tungsten nucleation layer during a thermal
chemical vapor deposition process within the processing
chamber.
14. The method of claim 13, wherein the lid plate is heated by a
resistive heating element therein.
15. The method of claim 14, wherein the lid plate is heated to a
temperature within a range from about 140.degree. C. to about
160.degree. C.
16. The method of claim 15, wherein the temperature is within a
range from about 145.degree. C. to about 155.degree. C.
17. The method of claim 13, wherein the first or third vapor
deposition process is a pulsed-CVD process comprising exposing the
substrate to pulses of a co-flowed gaseous mixture comprising
tungsten hexafluoride and silane or tungsten hexafluoride and
diborane.
18. The method of claim 13, wherein the first or third vapor
deposition process is an ALD process comprising exposing the
substrate sequentially to tungsten hexafluoride and silane or
tungsten hexafluoride and diborane.
19. The method of claim 13, wherein the second vapor deposition
process is a CVD process comprising exposing the substrate to a
co-flowed gaseous mixture comprising tungsten hexafluoride and
ammonia, tungsten hexafluoride, ammonia, and silane, or tungsten
hexafluoride, ammonia, and diborane.
20. The method of claim 13, wherein the second vapor deposition
process is an ALD process comprising exposing the substrate
sequentially to tungsten hexafluoride and ammonia, tungsten
hexafluoride, ammonia, and silane, or tungsten hexafluoride,
ammonia, and diborane.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of U.S. Ser. No. 60/887,142
(APPM/011741L), filed Jan. 29, 2007, and U.S. Ser. No. 60/944,085
(APPM/011741L02), filed Jun. 14, 2007, which are herein
incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] Embodiments of the invention generally relate to a
temperature controlled lid assembly for a processing chamber and a
method for depositing tungsten-containing materials on a substrate
by vapor deposition processes.
[0004] 2. Description of the Related Art
[0005] Modern integrated circuits contain large numbers of
transistors. These transistors are generally field effect
transistors that contain a source region and a drain region with a
gate electrode located in between the source and drain regions.
[0006] A typical gate structure contains a thin polysilicon
electrode that lies on top of a thin layer of gate oxide such as
silicon oxide. The gate electrode and gate oxide are formed between
semi-conducting source and drain regions, that define an underlying
well of p-type or n-type silicon. The source and drain regions are
doped opposite to the well to define the gate location, a layer of
insulating material such as silicon oxide, silicon nitride, or
silicon oxynitride is deposited on top of the source and drain
regions and an aperture or via is formed in the insulating material
between the source and drain regions. The gate structure within the
via contains a thin oxide layer, a polysilicon layer and a metal
plug. The metal plug is typically formed by vapor depositing a
metal such as tungsten on top of the polysilicon gate electrode. To
complete the connection, the silicon then is caused to diffuse into
the tungsten during a thermal annealing process forming a layer of
relatively uniform tungsten silicide as the connection to the gate
electrode. Without annealing, the silicon will ultimately diffuse
into the tungsten forming a non-uniform layer of tungsten
silicide.
[0007] A gate electrode having an electrical connection made of
pure tungsten would be more desirable than a tungsten silicide
electrode since tungsten has a lower resistivity than tungsten
silicide. Unfortunately, silicon diffuses into the tungsten forming
tungsten silicide. The diffusion can be prevented by depositing a
layer of tungsten nitride as a diffusion barrier between the
tungsten and the silicon. Tungsten nitride is a good conductor as
well as an excellent diffusion barrier material. Such a barrier
layer is typically formed by reducing tungsten hexafluoride
(WF.sub.6) with ammonia (NH.sub.3) in a chemical vapor deposition
(CVD) process or an atomic layer deposition (ALD) process.
[0008] Unfortunately, the above described process results in the
formation of contaminant particles in the form of solid byproducts.
These byproducts include ammonia adducts of tungsten hexafluoride
((NH.sub.3).sub.4.WF.sub.6), ammonium fluoride (NH.sub.4F), and
other ammonium complexes. Many of these particles become attached
to the interior of the deposition chamber. During temperature
fluctuations within the chamber, the deposits flake off the walls
and contaminate the wafer. Further, the tungsten nitride that is
deposited using the above described process has a polycrystalline
structure in which there are many grain boundaries. As a result,
the diffusion barrier properties of the tungsten nitride are
compromised. In addition, tungsten nitride films deposited by the
traditional method tend not to adhere very well to the substrate
upon which they are deposited.
[0009] Therefore, there is a need for an apparatus and a process
for depositing tungsten-containing materials, wherein a tungsten
precursor may be flowed with or exposed to another reagent without
contaminating the processing chamber or the substrate surface.
SUMMARY OF THE INVENTION
[0010] In one embodiment, a processing chamber for depositing a
material by vapor deposition is provided which includes a lid
assembly attached to a chamber body, wherein the lid assembly
contains a lid plate, a showerhead, a mixing cavity, and a
distribution cavity, and a resistive heating element contained
within the lid plate. In one example, the resistive heating element
is configured to provide the lid plate at a temperature within a
range from about 120.degree. C. to about 180.degree. C.,
preferably, from about 140.degree. C. to about 160.degree. C., more
preferably, from about 145.degree. C. to about 155.degree. C., such
as about 150.degree. C. The mixing cavity is in fluid communication
with a tungsten precursor source and a nitrogen precursor source,
wherein the tungsten precursor source generally contains tungsten
hexafluoride and the nitrogen precursor source generally contains
ammonia. In some embodiments, the lid assembly further contains a
liquid channel attached to a temperature regulating system. Also,
the chamber body further contains a substrate support pedestal
having a heater.
[0011] In another embodiment, a processing chamber for depositing a
tungsten-containing material by vapor deposition is provided which
includes a lid assembly attached to a chamber body, wherein the lid
assembly contains a lid plate, a showerhead, a mixing cavity, and a
distribution cavity, a resistive heating element contained within
the lid plate, a tungsten precursor source coupled to and in fluid
communication with the lid assembly, and a nitrogen precursor
source coupled to and in fluid communication with the lid
assembly.
[0012] In other embodiments, the processing chamber contains a
reducing agent precursor source coupled to and in fluid
communication with the lid assembly. The reducing agent precursor
source contains a reducing agent, such as silane, hydrogen,
diborane, disilane, phosphine, derivatives thereof, or combinations
thereof. In one embodiment, a first valve is positioned between the
tungsten precursor source and the lid assembly, a second valve is
positioned between the nitrogen precursor source and the lid
assembly, and a third valve is positioned between the reducing
agent precursor source and the lid assembly. Each of the first
valve, the second valve, and the third valve is independently
controlled by a programmable logic controller. In one example, the
programmable logic controller is configured to sequentially open
and close the first and third valves while forming a tungsten
nucleation layer during an atomic layer deposition process. In
another example, the programmable logic controller is configured to
simultaneously open and close the first and second valves while
forming a tungsten nitride layer during a chemical vapor deposition
process. In another example, the programmable logic controller is
configured to sequentially open and close the first and second
valves while forming a tungsten nitride layer during a second
atomic layer deposition process. In another example, the
programmable logic controller is configured to open and close the
third valve during a pre-nucleation soak process or a
post-nucleation soak process.
[0013] In one embodiment, a method for forming a
tungsten-containing material on a substrate is provided which
includes positioning a substrate within a processing chamber
comprising a lid plate, heating the lid plate to a temperature
within a range from about 120.degree. C. to about 180.degree. C.,
depositing a tungsten nitride layer on the substrate during a vapor
deposition process within the processing chamber, and depositing a
tungsten nucleation layer on the tungsten nitride layer during an
atomic layer deposition process within the processing chamber.
[0014] In another embodiments, a method for forming a
tungsten-containing material on a substrate is provided which
includes positioning a substrate within a processing chamber
containing a lid plate, heating the lid plate to a temperature
within a range from about 120.degree. C. to about 180.degree. C.,
depositing a first tungsten nucleation layer on the substrate
during a first atomic layer deposition process within the
processing chamber, depositing a tungsten nitride layer on the
first tungsten nucleation layer during a vapor deposition process
within the processing chamber, and depositing a second tungsten
nucleation layer on the tungsten nitride layer during a second
atomic layer deposition process within the processing chamber.
[0015] In another embodiments, a method for forming a
tungsten-containing material on a substrate is provided which
includes positioning a substrate within a processing chamber
containing a lid plate, heating the lid plate to a temperature
within a range from about 120.degree. C. to about 180.degree. C.,
exposing the substrate to a reducing gas during a pre-nucleation
soak process, depositing a first tungsten nucleation layer on the
substrate during a first atomic layer deposition process within the
processing chamber, depositing a tungsten nitride layer on the
first tungsten nucleation layer during a vapor deposition process
within the processing chamber, and depositing a second tungsten
nucleation layer on the tungsten nitride layer during a second
atomic layer deposition process within the processing chamber.
[0016] In another embodiments, a method for forming a
tungsten-containing material on a substrate is provided which
includes positioning a substrate within a processing chamber
containing a lid plate, heating the lid plate to a temperature
within a range from about 120.degree. C. to about 180.degree. C.,
exposing the substrate to a reducing gas during a pre-nucleation
soak process, depositing a first tungsten nucleation layer on the
substrate during a first atomic layer deposition process within the
processing chamber, depositing a tungsten nitride layer on the
first tungsten nucleation layer during a vapor deposition process
within the processing chamber, depositing a second tungsten
nucleation layer on the tungsten nitride layer during a second
atomic layer deposition process within the processing chamber, and
exposing the substrate to another reducing gas during a
post-nucleation soak process.
[0017] In other embodiments, the method provides that the lid plate
is heated to a temperature within a range from about 140.degree. C.
to about 160.degree. C., preferably, from about 145.degree. C. to
about 155.degree. C., more preferably, at about 150.degree. C. The
tungsten nitride layer may be deposited during a chemical vapor
deposition process, wherein a tungsten precursor and a nitrogen
precursor are co-flowed during the chemical vapor deposition
process. In one embodiment, the tungsten precursor contains
tungsten hexafluoride and the nitrogen precursor contains
ammonia.
[0018] In other embodiments, the method provides that the substrate
is exposed to a reducing agent during the pre-nucleation soak
process or the post-nucleation soak process. The reducing agent may
contain silane, hydrogen, diborane, disilane, phosphine,
derivatives thereof, or combinations thereof. Other examples
provide that a bulk tungsten layer is deposited on the tungsten
nucleation layer during a thermal chemical vapor deposition
process.
[0019] In other embodiments, an angled mixer and a lid assembly
that may be utilized on a processing chamber are disclosed herein.
The lid assembly may have both heating elements and cooling
channels to permit rapid heating and cooling of the chamber lid so
that multiple depositions may occur within the same processing
chamber at different temperatures. The mixer may be angled to be
disposed within a central area of the lid assembly. The mixer may
have an opening at the top to permit cleaning gas to enter the
processing chamber, a second opening to permit introduction of a
first deposition gas, and a third opening to permit introduction of
a second deposition gas perpendicular to the flow of the first
deposition gas so that the first and second deposition gases
effectively mix within the mixer before being exposed to the
substrate.
[0020] In one embodiment, a mixer contains a mixer body having a
base portion, a shaft portion substantially perpendicular to the
base portion, one or more first gas introduction holes having a
first diameter along the shaft portion, and one or more second gas
introduction holes having a second diameter less than the first
diameter disposed along the shaft portion.
[0021] In another embodiment, a lid assembly contains one or more
heating elements, one or more cooling channels, a hole disposed
about the center axis of the lid assembly and through the lid
assembly, a notch disposed adjacent to and coupled with the hole,
and a cavity disposed adjacent to and coupled with the hole.
[0022] In another embodiment, a lid assembly contains a lid body
and a mixer body coupled with the lid body. The lid body contains
one or more heating elements, one or more cooling channels, and a
notch disposed within an upper surface of the lid body. The a mixer
body contains a base portion, a shaft portion substantially
perpendicular to the base portion, one or more first gas
introduction holes having a first diameter along the shaft portion,
and one or more second gas introduction holes having a second
diameter less than the first diameter disposed along the shaft
portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] So that the manner in which the above recited features of
the invention can be understood in detail, a more particular
description of the invention, briefly summarized above, may be had
by reference to embodiments, some of 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.
[0024] FIG. 1 depicts a schematic cross sectional view of a
processing chamber having a lid assembly and mixer according to an
embodiment described herein;
[0025] FIG. 2A depicts a schematic cross sectional view of an
angled mixer according to another embodiment described herein;
[0026] FIG. 2B depicts a top view of the angled mixer of FIG.
2A;
[0027] FIGS. 2C and 2D depict isometric views of the angled mixer
of FIG. 2A;
[0028] FIG. 3A depicts a top view of a secondary lid assembly
according to another embodiment described herein;
[0029] FIG. 3B depicts a bottom view of the lid assembly of FIG.
3A;
[0030] FIG. 3C depicts a bottom cross sectional view of the lid
assembly of FIG. 3A;
[0031] FIG. 3D depicts a cross sectional view of the lid assembly
of FIG. 3A;
[0032] FIGS. 4-6 depict a schematic of a processing chamber
according to other embodiments described herein; and
[0033] FIGS. 7-9 depict a schematic of another processing chamber
according to other embodiments described herein.
[0034] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures. It is contemplated that elements
disclosed in one embodiment may be beneficially utilized on other
embodiments without specific recitation.
DETAILED DESCRIPTION
[0035] Embodiments of the invention provide a processing chamber
for depositing a material by vapor deposition. In one embodiment,
the processing chamber includes a lid assembly attached to a
chamber body, wherein the lid assembly contains a lid plate, a
showerhead, a mixing cavity, a distribution cavity, and a resistive
heating element contained within the lid plate. In one example, the
resistive heating element is configured to provide the lid plate at
a temperature within a range from about 120.degree. C. to about
180.degree. C., preferably, from about 140.degree. C. to about
160.degree. C., more preferably, from about 145.degree. C. to about
155.degree. C., such as about 150.degree. C. The mixing cavity is
in fluid communication with a tungsten precursor source and a
nitrogen precursor source, wherein the tungsten precursor source
generally contains tungsten hexafluoride and the nitrogen precursor
source generally contains ammonia.
[0036] Embodiments of the apparatuses and processes as described
herein are useful to deposit tungsten-containing materials while
avoiding contamination of the processing chamber or substrate of
various byproducts, including ammonia adducts of tungsten
hexafluoride ((NH.sub.3).sub.4.WF.sub.6), ammonium fluoride
(NH.sub.4F), and other ammonium complexes.
[0037] Embodiments of the invention provide an angled mixer and lid
assembly for a processing chamber. The lid assembly may have both
heating elements and cooling channels to permit rapid heating and
cooling of the chamber lid so that multiple depositions may occur
within the same processing chamber at different temperatures. The
mixer may be angled to be disposed within a central area of the lid
assembly. The mixer may have an opening at the top to permit a
cleaning gas to enter the processing chamber, a second opening to
permit introduction of a first deposition gas, and a third opening
to permit introduction of a second deposition gas perpendicular to
the flow of the first deposition gas so that the first and second
deposition gases effectively mix within the mixer before being
exposed to the substrate.
[0038] As described below, the angled mixer and the lid assembly
may be used to form tungsten-containing materials by vapor
deposition processes as described herein. The tungsten-containing
materials may contain metallic tungsten, tungsten nitride, tungsten
silicide, tungsten boride, tungsten phosphide, derivatives thereof,
or combinations thereof. A processing chamber may be used to
perform chemical vapor deposition (CVD), plasma-enhanced CVD
(PE-CVD), pulsed-CVD, atomic layer deposition (ALD),
plasma-enhanced ALD (PE-ALD), derivatives thereof, or combinations
thereof. Processing chambers for CVD and ALD processes are
commercially available from Applied Materials, Inc., located in
Santa Clara, Calif. In some embodiments, the processing chamber for
depositing tungsten-containing materials may contain an in situ
plasma source or a remote plasma source.
[0039] FIG. 1 is a schematic cross sectional view of processing
chamber 100 having lid assembly 101 and angled mixer 110 according
to one embodiment of the invention. Processing chamber 100 contains
chamber body 102 with susceptor 104 for supporting substrate 106
opposite showerhead 108. Chamber body 102 may be enclosed by two
lids, such as inner lid 112 and outer lid 118. Outer lid 118 may
encircle the outside of chamber body 102 and may contain one or
more cooling channels 120 to maintain the chamber body at a
predetermined temperature. Chamber body 102, showerhead 108, inner
lid 112, and outer lid 118 may independently be formed of or
contain a metal, such as aluminum, stainless steel, or alloys
thereof.
[0040] Inner lid 112 may also contain one or more cooling channels
114. Additionally, inner lid 112 may contain one or more heating
elements 116. Both the cooling channels 114 and heating elements
116 may be embedded in inner lid 112. The presence of both heating
elements 116 and cooling channels 114 in inner lid 112 permit the
rapid increase in temperature and decrease in temperature that may
be necessary to deposit both tungsten and tungsten nitride at
different temperatures within the same processing chamber 100 as
well as cleaning processing chamber 100.
[0041] Angled mixer 110 may be disposed within inner lid 112 for
introduction of both deposition gases and cleaning gases into
processing chamber 100. Cleaning gases may be provided from
cleaning gas panel 122 through top 124 of angled mixer 110. A first
deposition gas may be provided to angled mixer 110 from first gas
panel 126 through opening 128 disposed on a side surface of angled
mixer 110. A second deposition gas may be provided to angled mixer
110 from second gas panel 130 to notch 132 disposed in inner lid
112 adjacent angled mixer 110. Notch 132 permits the second gas to
travel around the outside of angled mixer 110 and then inject into
angled mixer 110 through one or more holes.
[0042] FIG. 2A is a schematic cross sectional view of angled mixer
206 according to one embodiment of the invention. FIGS. 2C and 2D
are isometric views of angled mixer 206 of FIG. 2A. Angled mixer
206 may be disposed in lid assembly 200 having lid 202 and gas
inlet manifold 204. Angled mixer 206 may extend through lid 202 and
into gas inlet manifold 204. Angled mixer 206 may be coupled with
lid 202 with one or more fastening mechanisms disposed through
openings 208a and 208b in base portion 228 of angled mixer 206. One
or more vacuum channels 210a and 210b may be coupled with openings
208a and 208b to permit drawing a vacuum and pulling angled mixer
206 into tight contact with lid 202. Vacuum channels 210a and 210b
may have different widths as shown by arrows "H" and "J" in FIG.
2B.
[0043] In one embodiment, the ratio of the widths of vacuum
channels 210a and 210b may be within a range from about 1.6 to
about 2.0, preferably, from about 1.75 to about 1.95, and more
preferably, from about 1.85 to about 1.90. In one example, the
ratio of the widths of vacuum channels 210a and 210b may be about
1.875. Openings 208a and 208b may be offset on angled mixer 206
such that one opening 208a may be spaced a distance "B" from the
center of angled mixer 206 and the other opening 208b may be spaced
a second, different distance "C" from the center of angled mixer
206. In one embodiment, the ratio of the distance "C" to the
distance "B" may be about 1.3. Openings 208a and 208b may be offset
so angled mixer 206 may be coupled with lid 202 in the correct
orientation.
[0044] Angled mixer 206 also contains shaft portion 230 having
inner wall 212 having a substantially constant diameter "D" and
outer wall 216 that is angled relative to inner wall 212.
Additionally, outer wall 216 is angled relative to wall 218 of lid
202 and wall 220 of gas inlet manifold 204. Outer wall 216 is
angled as shown by arrows "A". The angled outer wall 216 relative
to the substantially straight walls 218 and 220 of lid 202, and gas
inlet manifold 204 respectively permit angled mixer 206 to be
easily inserted into lid assembly 200 without outer wall 216
scraping walls 218 and 220 while also permitting a tight fit at a
location corresponding to where shaft portion 230 meets base
portion 228 of angled mixer 206.
[0045] A cleaning gas may be introduced to the processing chamber
through opening 222 in angled mixer 206 that is coupled with a
cleaning gas introduction tube 232. Opening 222 may be disposed at
the top of shaft portion 230 of angled mixer 206 such that the
cleaning gas may clean the entire angled mixer 206. A first
deposition gas may be provided to angled mixer 206 through opening
224 in shaft portion 230 of angled mixer 206. The first deposition
gas flows downward through shaft portion 230 of angled mixer 206 as
shown by the arrows "E". A second deposition gas may be introduced
to notch 214 formed between outer wall 216 of shaft portion 230 of
angled mixer 206 and walls 218 and 220 of lid 202 and gas inlet
manifold 204. The second deposition gas may flow around the outside
of angled mixer 206 and then inject into angled mixer 206 through
holes 226 formed in notch 214 of shaft portion 230 in a direction
substantially perpendicular to the flow of the first deposition gas
as shown by the arrows "F". In one embodiment, eight holes 226 may
be present. The cross-flow of the second deposition gas may permit
the first and secondary gases to sufficiently mix as they
collectively flow down through angled mixer 206 as shown by the
arrows "G". In one embodiment, the diameter of holes 226 is less
than the diameter of opening 224. Opening 222 may have a diameter
that is different than the diameter of opening 224 and holes
226.
[0046] FIG. 3A is a top view of lid assembly 300 according to one
embodiment of the invention. FIG. 3B is a bottom view of lid
assembly 300 of FIG. 3A. FIG. 3C is a bottom cross sectional view
of lid assembly 300 of FIG. 3A. FIG. 3D is a cross sectional view
of lid assembly 300 of FIG. 3A. Lid assembly 300 contains top
portion 302 having a non-circular outer wall 306 and bottom portion
304 having a substantially circular outer wall 308. In one
embodiment, top portion 302 and bottom portion 304 are a unitary
piece. In another embodiment, top portion 302 and bottom portion
304 are separate pieces coupled together. Hole 312 may be present
through lid assembly 300 to permit insertion of a mixer. Hole 312
may be substantially cylindrically shaped and have a substantially
uniform diameter as shown by arrows "K". Therefore, a mixer
inserted into hole 312 tightly fits therein.
[0047] Notch 314 may be present to permit deposition gas to be
provided to the mixer once inserted into lid assembly 300. Sealing
cavity 310 may be present to permit lid assembly 300 to be coupled
with a gas inlet manifold (not shown). A cavity portion 316 may be
present for the base portion of a mixer to be coupled to lid
assembly 300.
[0048] Heating element 318 may be disposed within lid assembly 300
to heat the processing gas and lid assembly 300. Heating element
318 may have multiple turns and winds through lid assembly 300 and
may even turn back upon itself. In one embodiment, heating element
318 may contain aluminum. Heating elements 318 containing aluminum
may be beneficial because the aluminum, as compared to conventional
stainless steel heating elements, may prevent warping. One or more
cooling channels 320 may also be present outside heating element
318 to rapidly cool lid assembly 300. One or more thermocouples 322
may be coupled with the lid to measure the temperature of lid
assembly 300. Having both heating elements 318 and cooling channels
320 coupled within the same lid permits the rapid cooling and rapid
heating necessary to perform both tungsten and tungsten nitride
deposition with the same processing chamber. The rapid heating and
cooling can permit successive deposition processes of tungsten and
tungsten nitride to occur within the same chamber without
sacrificing throughput.
[0049] In one embodiment, cooling channels 320 may be used to
regulate the temperature of lid assembly 300 during the vapor
deposition process for depositing a tungsten-containing material.
In one embodiment, lid assembly 101 may be heated or maintained at
a temperature within a range from about 120.degree. C. to about
180.degree. C., preferably, from about 140.degree. C. to about
160.degree. C., and more preferably, from about 145.degree. C. to
about 155.degree. C., such as about 150.degree. C., during the
vapor deposition process of a tungsten-containing material.
[0050] Temperature control may be useful to deposit both metallic
tungsten and tungsten nitride materials in the same chamber. For
example, to deposit metallic tungsten, lid assembly 300 may be
maintained at a temperature of about 25.degree. C. Thus, during
tungsten deposition, heating elements 318 may be turned off and lid
assembly 300 may be cooled by flowing a cooling fluid through
cooling channel 320. The cooling fluid may contain water, glycol
based fluid, or combinations thereof. Following the tungsten
deposition, the chamber may be purged of the tungsten deposition
gases. During the purging, the cooling fluid may be turned off and
removed from cooling channel 320 by forcing air or an inert gas
through cooling channel 320. The tungsten nitride deposition may
occur at about 150.degree. C. During the tungsten nitride
deposition, heating elements 318 may be turned on while the cooling
channel does not have a cooling fluid circulating therethrough.
[0051] A controller (not shown) may control the heating and
cooling. A series of valves may be used to control when the cooling
fluid is supplied to lid assembly 300. When the cooling fluid is
supplied to lid assembly 300, heating element 318 may not be on.
Similarly, when the cooling fluid is purged from cooling channel
320, heating element 318 may not be on. When the tungsten nitride
is deposited, cooling fluid may not be supplied to lid assembly
300. When the cooling fluid is supplied to cooling channel 320, the
air and/or inert gas may not be supplied to cooling channel 320.
When the air and/or inert gas is supplied to cooling channel 320,
cooling fluid may not be supplied to cooling channel 320. If the
temperature of lid assembly 300 as measured by thermocouples 322 is
greater than about 85.degree. C., cooling fluid may not be supplied
to the cooling channels 320. If the temperature of lid assembly 300
is greater than about 180.degree. C., then heating elements 318 may
be turned off. If the lid assembly temperature is greater than
about 65.degree. C., the chamber may not be vented.
[0052] In one embodiment, the primary lid discussed above in
reference to FIG. 1 may be maintained at a temperature of about
25.degree. C. during the tungsten nitride deposition. In one
embodiment, the primary lid may be maintained at a temperature of
about 65.degree. C. The deposition of the tungsten nitride may
occur at about 2 kW in power and about 10 amps. In another
embodiment, the deposition of tungsten nitride may occur at about 3
kW in power and about 15 amps. An angled mixer disposed in a
secondary lid assembly having both heating elements and cooling
channels may permit deposition of tungsten and tungsten nitride
within the same chamber.
[0053] In another embodiment, FIGS. 4-6 illustrate processing
chamber 450 that may be used to form tungsten-containing materials
by vapor deposition process as described herein. The
tungsten-containing materials may contain metallic tungsten,
tungsten nitride, tungsten silicide, tungsten boride, tungsten
phosphide, derivatives thereof, or combinations thereof. Processing
chamber 450 may be used to perform CVD, PE-CVD, pulsed-CVD, ALD,
PE-ALD, derivatives thereof, or combinations thereof. Water
channels, such as convolute liquid channel 562, may be used to
regulate the temperature of lid assembly 400 during the vapor
deposition process for depositing a tungsten-containing material.
In one embodiment, lid assembly 400 may be heated or maintained at
a temperature within a range from about 120.degree. C. to about
180.degree. C., preferably, from about 140.degree. C. to about
160.degree. C., and more preferably, from about 145.degree. C. to
about 155.degree. C., such as about 150.degree. C., during the
vapor deposition process of a tungsten-containing material.
[0054] Showerhead 556 has a relatively short upwardly extending rim
558 screwed to gas box plate 560. Both showerhead 556 and gas box
plate 560 may be formed from or contain a metal, such as aluminum,
stainless steel, or alloys thereof. Convolute liquid channel 562,
illustrated in FIG. 6, is formed in the top of gas box plate 560
and covered and sealed by water cooling cover plate 434. Water is
generally flown through convolute liquid channel 562. However,
alcohols, glycol ethers, and other organic solvents may be used
solely or mixed with water to transfer heat away from or to lid
assembly 400. Water ports 448 and 449 through water cooling cover
plate 434 are illustrated in FIGS. 4-5, water ports 448 and 449
connect ends 564 and 566 of liquid channel 562 near to the center
of gas box plate 560. Convolute liquid channel 562 is formed in a
serpentine though generally circumferential path having bends 568
(e.g., three sharp U-turns or U-shaped bends) as the path
progresses from the inside to the outside until the path returns to
the inside in radial channel 570. Liquid channel 562 is narrow
enough and bends 568 are sharp enough to ensure that the flow of
water becomes turbulent, thus aiding the flow of heat from the
flange of gas box plate 560 to the water in channel 562. A liquid
temperature regulating system (not shown) may be attached to water
ports 448 and 449 and convolute liquid channel 562 and used to
transfer heat away from or to lid assembly 400. In one example, lid
assembly 400 is configured to be heated or maintained at a
temperature of about 150.degree. C. and is in fluid communication
with a source of tungsten precursor (e.g., WF.sub.6) and a source
of a nitrogen precursor (e.g., NH.sub.3).
[0055] FIGS. 4 and 5 depict upwardly extending rim 558 of
showerhead 556 attached to bottom rim 572 of gas box plate 560.
Both rims 558 and 572 are maximally sized between encompassing lid
isolator 574 and encompassed lower cavity 430 of showerhead 556.
The screw fastening between showerhead 556 and gas box plate 560
ensures good thermal contact over the maximally sized contact area.
The thermal flow area extends from the outside at lid isolator 574
(except for a gap between lid isolator 574 and either showerhead
556 or gas box plate 560) to the inside at lower cavity 430. The
structure of water cooling channels 562 provides efficient thermal
transfer between the water and gas box plate 560, and the
mechanical interface between the flange of gas box plate 560 and
showerhead 556 ensures efficient thermal transfer between them.
Accordingly, the cooling of showerhead 556 is greatly enhanced.
[0056] Processing chamber 450 further contains heater pedestal 552
connected to pedestal stem 554 that may be vertical moved within
processing chamber 450. The heater portion of heater pedestal 552
may be formed of a ceramic. In its upper, deposition position,
pedestal 552 holds the substrate in close opposition to lower
surface 582 of showerhead 556, processing region 426 being defined
between pedestal 552 and lower surface 582 of showerhead 556.
Showerhead 556, has a large number of apertures or holes 580
communicating between lower cavity 430 and processing region 426 to
allow the passage of processing gas. The processing gas is supplied
through gas port 432 formed at the center of water-cooled gas box
plate 560 made of aluminum. The upper side of gas box plate 560 is
covered by water cooling cover plate 434 surrounding the upper
portion of gas box plate 560 that includes gas port 432. Gas port
432 supplies the processing gases to upper cavity 438 separated
from lower cavity 430 by blocker plate 440, also having a large
number of holes 580 therethrough. One purpose of cavities 430 and
438, showerhead 556, and blocker plate 440 is to evenly distribute
the processing gas over the upper face of the substrate.
[0057] The substrate may be supported on pedestal 552, which is
illustrated in a raised, deposition position. In a lowered, loading
position, lifting ring 416 attached to lift tube 417 lifts four
lift pins 418 fit to slide into pedestal 552 so that lift pins 418
can receive the substrate loaded into the chamber through loadlock
port 419 in chamber body 420. In one embodiment, pedestal 552 may
contain an optional confinement ring 610, such as during
plasma-enhanced vapor deposition processes.
[0058] Lid isolator 574 is interposed between showerhead 556 and
lid rim 466, which can be lifted off chamber body 420 to open
processing chamber 450 for maintenance access. The vacuum within
processing chamber 450 is maintained by vacuum pump 470 connected
to pump plenum 472 within processing chamber 450, which connects to
annular pumping channel 474.
[0059] As illustrated in FIG. 4, annular chamber liner 680 made of
quartz not only defines a side of pumping channel 474 but also
partially defines a further choke aperture 682 between processing
region 426 and pumping channel 474. Annular chamber liner 680 also
supports confinement ring 610 in the lowered position of pedestal
552. Chamber liner 680 also surrounds a circumference at the back
of pedestal 552. Chamber liner 680 rests on narrow ledge 683 in
chamber body 420, but there is little other contact, so as to
minimize thermal transport. Below chamber liner 680 is located a
Z-shaped lower chamber shield 684, preferably made of opaque
quartz. Lower chamber shield 684 rests on the bottom of chamber
body 420 on annular boss 686 formed on the bottom of lower chamber
shield 684. The quartz prevents radiative coupling between the
bottom of pedestal 552 and chamber body 420, and annular boss 686
minimizes conductive heat transfer to chamber body 420. In an
alternative embodiment, lower chamber shield 684 includes an
inwardly extending bottom lip joined to a conically shaped upper
portion conforming to the inner wall of chamber body 420. While
this alternative design is operationally satisfactory, the sloping
shape is much more expensive to fabricate in quartz.
[0060] In another embodiment, FIGS. 7-9 illustrate processing
chamber 750 containing convolute liquid channel 562 and resistive
heating element 770 that may be used to form tungsten-containing
materials by vapor deposition process as described herein.
Resistive heating element 770 may be a wire and may be formed of or
contain a metal such as copper, aluminum, steel, stainless steel,
nickel, alloys thereof, or combinations thereof. Resistive heating
element 770 may be convolute about gas box plate 760 or may take on
a variety of shapes. In one example, resistive heating element 770
contains aluminum and is configured to create a controllable
temperature gradient across lower surface 761 of gas box plate 760.
Preferably, resistive heating element 770 is configured to create a
consistent temperature across lower surface 761 of gas box plate
760.
[0061] In other embodiments, processing chamber 750 is connected to
and in fluid communication with sources 720, 722, 724, and 726. In
one configuration, source 720 is a carrier gas source and contains
a carrier gas, source 722 is a tungsten gas source and contains a
tungsten precursor, source 724 is a nitrogen source and contains a
nitrogen precursor, source 726 is a reducing agent gas source and
contains a reducing agent. Valve 730 may be positioned between
source 720 and gas port 432, valve 732 may be positioned between
source 722 and gas port 432, valve 734 may be positioned between
source 724 and gas port 432, and valve 736 may be positioned
between source 726 and gas port 432. Programmable logic controller
(PLC) 738 may be used to control the opening and closing of valves
730, 732, 734, and 736 during a CVD process, a pulsed-CVD process,
or an ALD process. Valve 730 may be left turned on to provide a
steady stream or flow of a carrier gas from source 720.
[0062] In one example, source 720 may contain a carrier gas such as
nitrogen, argon, hydrogen, forming gas, or mixtures thereof. Source
722 may have a tungsten precursor, such as tungsten hexafluoride
and source 724 may have a nitrogen precursor such as ammonia. A
reducing agent may be contained within source 726, which is coupled
to and in fluid communication with lid assembly 700. The reducing
agent may be silane, hydrogen, diborane, disilane, phosphine,
derivatives thereof, or combinations thereof.
[0063] Valve 732 may be positioned between source 722 containing
the tungsten precursor and lid assembly 700, valve 734 positioned
between source 724 containing the nitrogen precursor and lid
assembly 700, and valve 736 positioned between source 726 and the
reducing agent and lid assembly 700. Each of valves 720, 722, 724,
and 726 is independently controlled by PLC 738. In one example, PLC
738 is configured to sequentially open and close valves 722 and 726
while forming a tungsten nucleation layer during an ALD process. In
another example, PLC 738 is configured to simultaneously open and
close valves 722 and 724 while forming a tungsten nitride layer
during a CVD process. In another example, PLC 738 is configured to
sequentially open and close valves 722 and 744 while forming a
tungsten nitride layer during a second ALD process. In another
example, PLC 738 is configured to open and close valve 736 during a
pre-nucleation soak process or a post-nucleation soak process while
the substrate is exposed to a reducing agent delivered from source
726.
[0064] The tungsten-containing materials may contain metallic
tungsten, tungsten nitride, tungsten silicide, tungsten boride,
tungsten phosphide, derivatives thereof, or combinations thereof.
Processing chamber 750 may be used to perform CVD, PE-CVD,
pulsed-CVD, ALD, PE-ALD, derivatives thereof, or combinations
thereof. Controller 780 and resistive heating element 770 may be
used to regulate the temperature of lid assembly 700 during the
vapor deposition process for depositing a tungsten-containing
material. In one embodiment, lid assembly 700 or gas box plate 760
may be heated or maintained at a temperature within a range from
about 120.degree. C. to about 180.degree. C., preferably, from
about 140.degree. C. to about 460.degree. C., and more preferably,
from about 145.degree. C. to about 155.degree. C., such as about
150.degree. C., during the vapor deposition process of a
tungsten-containing material. Convolute liquid channel 562 may be
used to heat or cool lid assembly 700.
[0065] Showerhead 556 has a relatively short upwardly extending rim
558 screwed to gas box plate 760. Both showerhead 556 and gas box
plate 760 may be formed of a metal, such as aluminum, stainless
steel, or alloys thereof. Convolute liquid channel 562, illustrated
in FIG. 9, is formed in the top of gas box plate 760 and covered
and sealed by water cooling cover plate 434. Water is generally
flown through convolute liquid channel 562. However, alcohols,
glycol ethers, and other organic solvents may be used solely or
mixed with water to transfer heat away from or to lid assembly
700.
[0066] Water ports 448 and 449 through water cooling cover plate
434 are illustrated in FIGS. 8-9. Water ports 448 and 449 connect
ends 564 and 566 of liquid channel 562 near to the center of gas
box plate 760. Convolute liquid channel 562 is formed in a
serpentine though generally circumferential path having bends 568
(e.g., three sharp U-turns or U-shaped bends) as the path
progresses from the inside to the outside until the path returns to
the inside in radial channel 570. Liquid channel 562 is narrow
enough and bends 568 are sharp enough to ensure that the flow of
water or other fluids becomes turbulent, thus aiding the flow of
heat from the flange of gas box plate 760 to the water in channel
562. A liquid temperature regulating system (not shown) may be
attached to water ports 448 and 449 and convolute liquid channel
562 and used to transfer heat away from or to lid assembly 700. In
one example, lid assembly 700 is configured to be heated or
maintained at a temperature of about 150.degree. C. and is in fluid
communication with a source of tungsten precursor (e.g., WF.sub.6)
and a source of a nitrogen precursor (e.g., NH.sub.3).
[0067] Several CVD processing chambers that may be useful for some
of the deposition processes described herein may be further
described in commonly assigned U.S. Pat. Nos. 5,846,332, 6,079,356,
6,162,715, and 6,827,815, which are incorporated herein by
reference in their entirety. Several ALD processing chambers that
may be useful for some of the deposition processes described herein
may be further described in commonly assigned U.S. Pat. Nos.
6,660,126, 6,716,287, 6,821,563, 6,878,206, 6,916,398, 6,936,906,
6,998,014, 7,175,713, and 7,204,886, commonly assigned U.S. Ser.
No. 09/798,258, filed Mar. 2, 2001, and published as 2002-0121241;
U.S. Ser. No. 10/032,293, filed Dec. 21, 2001, and published as
2003-0116087; U.S. Ser. No. 10/356,251, filed Jan. 31, 2003, and
published as 2004-0065255; U.S. Ser. No. 10/268,438, filed Oct. 9,
2002, and published as 2004-0069227; U.S. Ser. No. 11/127,753,
filed May 12, 2005, and published as 2005-0271812; U.S. Ser. No.
10/281,079, filed Oct. 25, 2002, and published as 2003-0121608, and
commonly assigned U.S. Ser. Nos. 11/556,745, 11/556,752,
11/556,756, 11/556,758, and 11/556,763, each filed on Nov. 6, 2006,
and published as 2007-0119370, 2007-0119371, 2007-0128862,
2007-0128863, 2007-0128864, which are incorporated herein by
reference in their entirety.
[0068] In one embodiment, a processing chamber for depositing
tungsten-containing materials contains a lid plate containing an
embedded heating element disposed therein. In another embodiment, a
processing chamber for depositing tungsten-containing materials
contains a gas box plate containing an embedded heating element
disposed therein. In another embodiment, a processing chamber for
depositing tungsten-containing materials contains an insulating
jacket heater containing heating element disposed thereon. Heating
elements may be configured to generate more heat near a particular
region of lid plate, such as an inner region or an outer region. A
controller may be used to regulate the temperature of lid plate by
adjusting power levels to the heating element. In various
embodiments, the processing chamber for depositing
tungsten-containing materials may contain an in situ plasma source
or a remote plasma source.
[0069] In one embodiment, a tungsten nitride layer and a tungsten
nucleation layer are deposited during a vapor deposition process.
The lid plate may be heated to a temperature within a range from
about 140.degree. C. to about 160.degree. C., preferably, about
150.degree. C. A substrate may be exposed to a pre-soak gas
containing silane during a pre-soak process. The pre-soak process
may last for a time period within a range about 10 seconds to about
30 seconds, preferably about 20 seconds, while the processing
chamber may have an internal pressure within a range from about 50
Torr to about 150 Torr, preferably, about 90 Torr. A tungsten
nitride layer is deposited at a process temperature within a range
from about 375.degree. C. to about 425.degree. C., preferably,
about 400.degree. C. The pre-soak process and the tungsten nitride
deposition may be repeated about 25 times to form a tungsten
nitride material. Subsequently, a tungsten nucleation layer may be
deposited by an ALD process by repeating about 15 cycles of
exposing the substrate to the tungsten precursor and a reducing
agent (e.g., SiH.sub.4 or B.sub.2H.sub.6).
[0070] In one example, the tungsten nitride is deposited by a CVD
process wherein the tungsten precursor (e.g., WF.sub.6) is
co-flowed with the nitrogen precursor (e.g., NH.sub.3). The lid
assembly contains a lid plate heated to a temperature within a
range from about 120.degree. C. to about 180.degree. C.,
preferably, from about 140.degree. C. to about 160.degree. C., and
more preferably, from about 145.degree. C. to about 155.degree. C.,
such as about 150.degree. C. The processing chamber may have an
internal pressure within a range from about 2 Torr to about 20
Torr, such as about 6 Torr. In another example, the tungsten
nitride is deposited by an ALD process wherein the tungsten
precursor (e.g., WF.sub.6) is sequentially pulsed with the nitrogen
precursor (e.g., NH.sub.3). The substrate may be exposed to
multiple ALD cycles, wherein each ALD cycle exposes the substrate
to a pre-soak gas containing a reducing agent (e.g., SiH.sub.4 or
B.sub.2H.sub.6) for about 0.5 seconds, purge gas for about 2
seconds, tungsten precursor for about 1.5 seconds, purge gas for
about 2 seconds, nitrogen precursor for about 2.5 seconds, and
purge gas for about 2 seconds.
[0071] While the foregoing is directed to embodiments 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.
* * * * *