U.S. patent application number 10/855282 was filed with the patent office on 2004-11-04 for chemical vapor deposition apparatuses.
Invention is credited to Carpenter, Craig M., Dando, Ross S..
Application Number | 20040216671 10/855282 |
Document ID | / |
Family ID | 32177035 |
Filed Date | 2004-11-04 |
United States Patent
Application |
20040216671 |
Kind Code |
A1 |
Carpenter, Craig M. ; et
al. |
November 4, 2004 |
Chemical vapor deposition apparatuses
Abstract
A chemical vapor deposition apparatus includes a deposition
chamber defined at least in part by chamber walls, a substrate
holder inside the chamber, and at least one process chemical inlet
to the chamber. At least one purge inlet to the chamber is
positioned elevationally above the substrate holder and outside a
lateral periphery of the substrate holder. The purge inlet is
configured to inject at least one purge material into the chamber
and past the substrate holder. The purge inlet can be positioned
and configured to inject an annular purge material curtain
concentric to the substrate holder. A chemical vapor deposition
method includes injecting at least one purge material into a
deposition chamber and forming a purge curtain from the injected
purge material. The purge curtain can extend downward from
elevationally above a substrate holder and outside a lateral
periphery of the substrate holder. The purge curtain can flow past
the substrate holder.
Inventors: |
Carpenter, Craig M.; (Boise,
ID) ; Dando, Ross S.; (Nampa, ID) |
Correspondence
Address: |
WELLS ST. JOHN P.S.
601 W. FIRST AVENUE, SUITE 1300
SPOKANE
WA
99201
US
|
Family ID: |
32177035 |
Appl. No.: |
10/855282 |
Filed: |
May 26, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10855282 |
May 26, 2004 |
|
|
|
09805620 |
Mar 13, 2001 |
|
|
|
Current U.S.
Class: |
118/715 ;
118/728 |
Current CPC
Class: |
C23C 16/45544 20130101;
C23C 16/45519 20130101; C23C 16/45527 20130101 |
Class at
Publication: |
118/715 ;
118/728 |
International
Class: |
C23C 016/00 |
Claims
1. A chemical vapor deposition apparatus comprising: a deposition
chamber defined at least in part by chamber walls; a substrate
holder inside the chamber; at least one process chemical inlet to
the chamber positioned over the substrate holder; at least one
purge inlet to the chamber positioned elevationally above the
substrate holder and outside a lateral periphery of the substrate
holder and configured to inject at least one purge material into
the chamber and past the substrate holder.
2. The apparatus of claim 1 wherein, at a point of entry from the
purge inlet into the chamber, the purge inlet is comprised by at
least one of the chamber walls.
3. The apparatus of claim 2 wherein, at a point of entry from the
purge inlet into the chamber, the purge inlet is comprised at least
in part by one of the chamber walls comprising a lid.
4. The apparatus of claim 1 wherein the at least one purge inlet is
positioned and configured to inject a purge material curtain
concentric to the substrate holder.
5. The apparatus of claim 4 wherein the at least one purge inlet
comprises a plurality of inlets.
6. The apparatus of claim 1 wherein the process chemical inlet is
positioned elevationally above the substrate holder and inside a
lateral periphery of the substrate holder and is configured to
inject at least one process chemical into the chamber and to a
substrate received by the holder.
7. A chemical vapor deposition apparatus comprising: a deposition
chamber defined at least in part by chamber walls, one of the
chamber walls comprising a lid having an outer surface outside the
chamber and an inner surface inside the chamber; a substrate holder
inside the chamber; at least one process chemical inlet to the
chamber positioned over the substrate holder; and at least one
purge passageway through the lid from the outer surface to the
inner surface, the at least one purge passageway being separate
from the at least one process chemical inlet and being configured
to inject at least one purge material into the chamber and along at
least a portion of the chamber walls.
8. The apparatus of claim 7 wherein the process chemical inlet is
configured to inject at least one process chemical into the chamber
and to a substrate received by the holder.
9. The apparatus of claim 7 wherein the substrate holder comprises
a configuration arranged to receive only a single bulk
semiconductor wafer.
10. The apparatus of claim 7 wherein the chamber, substrate holder,
and purge passageway have relative positions and geometries
configured to direct less than a substantial amount of purge
material to a substrate received by the holder.
11. The apparatus of claim 7 wherein the at least one purge
passageway comprises a high pressure purge passageway and a
separate low pressure purge passageway.
12. The apparatus of claim 7 further comprising a flow director
inside the chamber laterally between the at least one purge
passageway and the at least one process chemical inlet.
13. The apparatus of claim 12 wherein the flow director comprises a
wall concentric to the substrate holder.
14. The apparatus of claim 7 wherein the at least a portion of the
chamber walls partially defines a dead space as to material
delivered from the process chemical inlet.
15. The apparatus of claim 7 wherein the lid is removable.
16. The apparatus of claim 7 wherein the purge passageway comprises
at least one entry port through the outer surface into an enclosed
channel laterally around the process chemical inlet and at least
one exit port from the enclosed channel through the inner
surface.
17. The apparatus of claim 16 wherein at least part of the enclosed
channel is annular.
18. The apparatus of claim 16 wherein the exit port comprises a
plurality of about equally spaced exit ports forming a ring of exit
ports around the substrate holder.
19. The apparatus of claim 16 wherein an intersection of the lid
and a second of the chamber walls forms an interior corner of the
chamber and a plurality of exit ports are spaced apart from the
corner.
20. The apparatus of claim 16 wherein an intersection of the lid
and a second of the chamber walls forms an interior corner of the
chamber and the at least one exit port is positioned at the corner
and defined in part by the second wall.
21. The apparatus of claim 20 wherein the enclosed channel
comprises an annular channel having a plurality of enclosed radial
channel extensions from the annular channel to one annular exit
port.
22-39 (Cancelled).
Description
TECHNICAL FIELD
[0001] The present invention pertains to chemical vapor deposition
apparatuses and purging devices in such apparatuses as well as
deposition methods and methods that provide purging during
deposition.
BACKGROUND OF THE INVENTION
[0002] Chemical vapor deposition (CVD) methods, such as, atomic
layer deposition (ALD) methods, are often used in semiconductor
processing and other industrial applications to form thin layers of
materials. One consideration in selecting a deposition method is
the process time to form a desired layer. Further, the quality of a
product produced by a deposition method can be important. Along
with an increasing need to reduce processing costs, a related
desire exists to reduce process time while improving or maintaining
product quality.
[0003] Speaking generally of ALD, a substrate is exposed to a first
precursor material that is chemisorbed onto the substrate. The
first precursor material is purged from the deposition chamber and
a second precursor is chemisorbed onto the first precursor material
on the substrate. Theoretically, the chemisorption of each
precursor material is self limiting and the deposited material is
formed one monolayer (1 atom thick) at a time. In practice, the
ideal theoretical deposition is often not achieved or may be
intentionally altered.
[0004] One potential cause for a deviation from ideal conditions is
the simultaneous presence of the first precursor and the second
precursor somewhere in a deposition apparatus other than on the
substrate. For example, failure to completely purge one of the
precursors from a deposition chamber may cause unwanted deposition
on chamber components when the other precursor is introduced.
Unwanted mixing of precursors can be a leading cause of particulate
formation and product contamination in ALD.
[0005] Accordingly, the need to improve product quality and
minimize down time for cleaning provides a motivation for careful
purging practices. Unfortunately, carefully purging increases
process time and accompanying process costs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Preferred embodiments of the invention are described below
with reference to the following accompanying drawings.
[0007] FIG. 1 shows a cross-sectional diagrammatic view of a
deposition chamber portion according to an aspect of the
invention.
[0008] FIG. 2 shows a top view of the deposition chamber portion of
FIG. 1.
[0009] FIG. 3 shows a cross-sectional view of the deposition
chamber portion in FIG. 1 taken along line 3-3.
[0010] FIG. 4 shows a cross-sectional diagrammatic view of a
deposition chamber portion according to another aspect of the
invention.
[0011] FIG. 5 shows a top view of the deposition chamber portion in
FIG. 4.
[0012] FIG. 6 shows a cross-sectional diagrammatic view of the
deposition chamber portion in FIG. 1 taken along lines 6-6.
[0013] FIG. 7 is a line chart of precursor A flowrate with respect
to time.
[0014] FIG. 8 is a line chart of precursor B flowrate with respect
to time.
[0015] FIG. 9 is a line chart of precursor purge flowrate with
respect to time.
[0016] FIG. 10 is a line chart of curtain purge flowrate with
respect to time according to one aspect of the invention.
[0017] FIG. 11 is a line chart of curtain purge flowrate with
respect to time according to an alternative aspect of the
invention.
[0018] FIG. 12 is a line chart of curtain purge flowrate with
respect to time according to another alternative aspect of the
invention.
[0019] FIG. 13 is a line chart of curtain purge flowrate with
respect to time according to a further alternative aspect of the
invention.
SUMMARY OF THE INVENTION
[0020] According to one aspect of the invention, a chemical vapor
deposition (CVD) apparatus can include a deposition chamber defined
at least in part by chamber walls, a substrate holder inside the
chamber, and at least one process chemical inlet to the chamber
positioned over the substrate holder. At least one purge inlet to
the chamber can be included and positioned elevationally above the
substrate holder and outside a lateral periphery of the substrate
holder. The purge inlet can be configured to inject at least one
purge material into the chamber and past the substrate holder. As
an example, the purge inlet can be comprised by at least one of the
chamber walls at a point of entry from the purge inlet into the
chamber. Also, the purge inlet can be positioned and configured to
inject a purge material curtain concentric to the substrate holder.
Accordingly, the at least one purge inlet can include a plurality
of inlets.
[0021] In another aspect of the invention, a CVD apparatus can
include a deposition chamber wherein one of the chamber walls is a
lid having an outer surface outside the chamber and an inner
surface inside the chamber. The apparatus can further include a
substrate holder inside the chamber, at least one process chemical
inlet to the chamber positioned over the substrate holder, and at
least one purge passageway through the lid from the outer surface
to the inner surface. The purge passageway can be separate from the
process chemical inlet and can be configured to inject at least one
purge material into the chamber and along at least a portion of the
chamber walls. For example, the chamber, substrate holder, and
purge passageway, can have relative positions and geometries
configured to direct less than a substantial amount of purge
material to a substrate received by the holder. The apparatus can
further include a flow director inside the chamber laterally
between the purge passageway and the process chemical inlet. A flow
director can include a wall concentric to the substrate holder. The
purge passageway can include at least one entry port through the
outer surface into an enclosed channel laterally around the process
chemical inlet. A plurality of exit ports can be provided from the
enclosed channel through the inner surface. The enclosed channel
can be annular.
[0022] In another aspect of the invention, a CVD method can include
injecting at least one purge material into a deposition chamber and
forming a purge curtain from the injected purge material. The purge
curtain can extend downward from elevationally above a substrate
holder and outside a lateral periphery of the holder to flow past
the holder. The purge curtain can extend from one of the chamber
walls that is a lid. The purge curtain can be concentric to the
substrate holder and flow axially with respect to the holder. The
purge curtain can also be annular. Preferably, the curtain is in a
laminar, as opposed to turbulent, flow regime so as not to create
any traps, eddies, etc. for process chemicals intended for
removal.
[0023] According to another aspect of the invention, a deposition
method can include injecting at least one deposition precursor into
a deposition chamber defined at least in part by chamber walls. A
first of the chamber walls can include a lid having an outer
surface outside the chamber and an inner surface inside the
chamber. The method can further include, while injecting the
precursor, separately injecting a purge material through at least
one purge passageway through the lid from the outer surface to the
inner surface. The injected purge material can flow along at least
a portion of the chamber walls. As an example, the method can
further include forming a curtain from the injected purge material
concentric to a second of the chamber walls, the curtain flowing
axially with respect to the chamber. The method can further include
forming an annular curtain from the injected purge material. Also,
the injecting purge material can further include delivering the
purge material through a dead space as to a precursor injected
without the purge injection.
[0024] In a further aspect of the invention, a deposition method
includes injecting at least one deposition precursor into a
deposition chamber, the precursor delivery occurring through at
least one process chemical port in a lid of the chamber. Delivery
of the precursor can be ceased and a purge material delivered
through at least one process chemical port. While delivering the
purge material through the process chemical port, a purge material
may be separately delivered through at least one purge port in the
lid, the purge delivery occurring along the chamber walls. The
method can further include not injecting the purge material through
the purge port during the injecting the precursor through the
process chemical port.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] This disclosure of the invention is submitted in furtherance
of the constitutional purposes of the U.S. Patent Laws "to promote
the progress of science and useful arts" (Article 1, Section
8).
[0026] It is a disadvantage of current atomic layer deposition
(ALD) chambers that dead spaces can exist along chamber walls and
in other spaces of the chamber. In the context of the present
document, "dead spaces" refers to spaces of stagnant flow as well
as traps, eddies, and other flow-related effects that can delay
direct passage of materials through a chamber. Process gases, such
as gas or liquid precursors, reactants, carriers, purges, and other
materials, can accumulate in the dead spaces and not be removed or
motivate extensive purging in an effort to remove process chemicals
from the dead spaces. Further, process chemicals accumulated in the
dead spaces can react, forming particulates. Also, particulates
formed in other parts of a deposition chamber can accumulate in the
dead spaces and remain after purging the chamber. Once particulates
form in the chamber, wafer contamination can result.
[0027] Accordingly, providing targeted purging to prevent process
chemicals from migrating into dead space or purging through dead
space can allow a decrease in purge time and/or decrease in
contamination. Targeted purging can be performed during all of the
pulse and purge cycles of ALD or only during selected parts of a
pulse/purge cycle. For example, targeted purging might be performed
only during the purge portion of a cycle or, alternatively, only
during a pulse portion of a cycle. Notably, the various aspects of
the invention described herein, are also applicable to non-ALD
types of chemical vapor deposition (CVD). Targeted purging during
CVD injection of multiple reactant species can isolate deposition
away from chamber walls, dead space, and other spaces in a
deposition chamber.
[0028] According to one aspect of the invention, a CVD apparatus
can include a deposition chamber defined at least in part by
chamber walls, a substrate holder inside the chamber, and at least
one process chemical inlet to the chamber positioned over the
substrate holder. The apparatus can further include at least one
purge inlet to the chamber. The purge inlet can be positioned
elevationally above the substrate holder and outside a lateral
periphery of the substrate holder. The purge inlet can further be
configured to inject at least one material into the chamber past
the substrate holder.
[0029] Deposition chambers applicable to the present invention can
have a variety of shapes and purposes. CVD includes various
subvarieties of deposition processes including but not limited to
ALD, plasma enhanced CVD, low pressure CVD, etc. Accordingly, a
deposition chamber that may be benefited by the aspects of the
invention described herein can possess a different structure
compared to the exemplary chambers shown in the figures. Once the
concepts of the invention described herein are understood, the
specific structures shown as examples in the figures can be adapted
to other deposition chambers. Similarly, a variety of substrate
holders can be suitable for the various deposition chambers. A
substrate holder can include a configuration arranged to receive
only a single bulk semiconductor wafer. A substrate holder can also
be configured to receive other substrates or to receive multiple
wafers.
[0030] Given the variety of chambers and substrate holders, a
variety of types and numbers of process chemical inlets can be used
in the present invention. The exemplary figures described herein
show a single process chemical inlet to a chamber for the sake of
simplicity. However, a "shower head" arrangement of multiple inlets
or other apparatuses for distributing process chemicals over a
substrate can be suitable. In summary, any deposition chamber,
substrate holder, or process chemical inlet known to those skilled
in the art or later recognized can be a candidate for practicing
the present invention by applying the concepts described
herein.
[0031] As one example, the process chemical inlet can be positioned
elevationally above the substrate holder and inside a lateral
periphery of the substrate holder. The process chemical inlet can
further be configured to inject at least one process chemical into
the chamber and to a substrate received by the holder. Such a
process chemical inlet can be contrasted to the purge inlet
described above that is positioned elevationally above the holder
as well, but outside a lateral periphery of the holder and
configured to inject purge material past the holder. A purge inlet
can be comprised by at least one of the chamber walls at a point of
entry from the purge inlet into the chamber. Preferably, the purge
inlet can be comprised at least in part by one of the chamber walls
comprising a lid. A lid of a deposition chamber can merely be a top
wall that is otherwise not separate or removable. Often, the lid is
a separate and removable component of a chamber to allow
maintenance of internal components. Accordingly, a lid can be
attached to form one wall of a chamber by clamping, bolting, or any
other acceptable method for a CVD apparatus. The lid could also be
welded or an integeral of other chamber walls, making in
nonremovable.
[0032] The purge inlet to a chamber, whether part of a lid, part of
a wall, or a component separate from chamber walls, can be
positioned and configured to inject a purge material curtain
concentric to the substrate holder. Further, the at least one purge
inlet described above can include a plurality of inlets.
[0033] In another aspect of the invention, the deposition chamber
can be defined in part by chamber walls, one of the chamber walls
comprising a lid having an outer surface outside the chamber and an
inner surface inside the chamber. The apparatus can further include
at least one purge passageway through the lid from the outer
surface to the inner surface. The purge passageway can be separate
from process chemical inlets and configured to inject at least one
purge material into the chamber and along at least a portion of the
chamber walls. The chamber, a substrate holder, and the purge
passageway can have relative positions and geometries configured to
direct less than a substantial amount of purge material to a
substrate received by the holder.
[0034] While a targeted purge as described herein can be
advantageous, a desire can arise in certain applications to avoid
interference of the targeted purge with simultaneous injection of
other process chemicals. Accordingly, directing less than less than
a substantial amount of purge material to a substrate can be
particularly advantageous. Such a feature can be accomplished
solely by a configuration and/or geometry of a purge passageway,
solely by a separate flow director, by combination of purge
passageway structure and a flow director, or by another feature in
keeping with the concepts described herein.
[0035] A flow director can be provided inside the chamber laterally
between the purge passageway and process chemical inlet. An
exemplary flow director can include a wall concentric to the
substrate holder. An exemplary purge passageway can include at
least one entry port through the outer surface of the lid into an
enclosed channel laterally around the process chemical inlet. The
purge passageway can further include at least one exit port from
the enclosed channel through the inner surface. The enclosed
channel can be annular. Also, the exit port can be a plurality of
about equally spaced exit ports forming a ring of exit ports around
the holder. The exit ports can be positioned in a ring orifice
formed in the lid.
[0036] Further, an intersection of the lid and a second of the
chamber walls can form an interior corner of the chamber. A
plurality of exit ports can be spaced apart from the corner.
Alternatively, the at least one exit port can be positioned at the
corner and defined in part by the second wall. Such exit port can
be provided when the enclosed channel includes an annular channel
having a plurality of enclosed radial channel extensions from the
annular channel to one annular exit port defined in part by the
second wall.
[0037] The passageway and its ports can further be configured to
provide specialized purge scenarios. For example, the at least one
purge passageway can include both a high pressure purge passageway
and a separate low pressure purge passageway. The entry and exit
ports from a purge passageway and other components of a passageway
might be advantageously adapted to a high pressure purge in a
different manner than adapted to a low pressure purge. In the
context of the present document "high pressure" refers to a
pressure at or above about 500 milliTorr while "low pressure"
includes pressures below about 200 milliTorr.
[0038] Turning to FIGS. 1-3, a deposition chamber apparatus 2 is
shown having a chamber body 4 and a chamber lid 6. Body 4 and lid 6
thus form chamber walls and at least in part define a chamber 36. A
substrate chuck 8 is shown inside chamber apparatus 2 and a single
bulk semiconductor wafer 10 is received on chuck 8. Process gases
14 are shown flowing through a process gas inlet 12 and into
chamber 36. As indicated by flow lines in FIG. 1, process gas 14 is
injected to wafer 10 on chuck 8 and continues in a flow path around
chuck 8 and out a vacuum port 28. A variety of process gas
distribution mechanisms may be suitable to accomplish the flow
pattern shown in FIG. 1 but are not shown specifically in FIG.
1.
[0039] A purge gas 18 is shown flowing through a purge entry port
16 into an annular purge channel 20 positioned outside the lateral
periphery of chuck 8. Purge gas 18 flows throughout purge channel
20 and enters chamber 36 through multiple purge exit ports 22.
Purge gas 18 enters chamber 36 and proceeds in the indicated flow
path along body 4 to vacuum port 28. Notably, a dead space 26
exists at a corner of body 4. Given the multiple purge exit ports
22 distributed around chuck 8, a curtain of purge gas can form
between process gas 14 and body 4. Purge gas 18 can thus isolate
process gas 14 away from body 4 and dead space 26. The flow rate of
purge gas 18 might even be adjusted such that purge gas 18 flows
through dead space 26.
[0040] An optional flow director 24 is shown extending from lid 6.
Flow director 24 helps minimize any backflow of purge gas 18 to
wafer 10. Optional flow director 24 can also act to direct purge
gas 18 through dead space 26. In FIGS. 1-3, flow director 24 is
essentially an annular wall. Such annular wall can be integrated
into lid 6, body 4, or another part of chamber apparatus 2.
Further, structures of other shapes can also be used as a flow
director.
[0041] Turning to FIGS. 4-6, an alternative chamber apparatus 38 is
shown substantially similar to chamber apparatus 2 of FIGS. 1-3
except that a different lid 30 is provided. Instead of purge exit
ports 22, lid 30 includes a plurality of radial channel extensions
32 from purge channel 20 allowing purge gas 18 to flow outward to a
single purge exit port 34. In FIGS. 4-6, purge exit port 34 is
essentially formed by an annular gap between a portion of lid 30
and body 4 at an intersection of lid 30 and body 4 forming an
interior corner of chamber apparatus 38. The multiple exits through
channel extensions 32 into purge exit port 34 can thus form a purge
curtain flowing along body 4 as shown in FIG. 4. As an alternative
to lid 30, although not shown, purge exit port 34 could comprise
multiple purge exit ports. Instead of a single annular gap between
lid 30 and body 4, such gaps could be limited to a region proximate
each channel extension 32. Accordingly, a separate purge exit port
could be provided for each channel extension 32. In other regions
not proximate a channel extension 32, lid 30 could extend
sufficiently to seal with body 4.
[0042] Notably, chamber apparatus 38 is not shown as including an
optional flow director. While a flow director could be provided
therein, it is expected that the flow dynamics produced by
positioning purge exit port 34 as indicated will also prevent
backflow of purge gas 18 to wafer 10.
[0043] Also not shown in FIGS. 1-6 are the variety of dimensions
and configurations for purge exit ports that can influence flow
dynamics of purge gas 18. As an example, if channel extensions 32
are formed as wide, shallow slits, then a high volume, low pressure
cascade of purge gas 18 can result. Modified channel extensions
that are also shallow but comparably more narrow could produce a
different flow regime, such as low volume, high pressure.
Accordingly, given the principles of the present invention
described herein, purge exit port 34, channel extensions 32, and/or
purge exit ports 22 can be configured to provide a desirable flow
regime for a particular deposition chamber apparatus. Once a
particular space within a deposition chamber is chosen for one of
the purging options described above, the purging apparatus can be
configured to provide the desired purge at the desired location. It
is further conceivable that multiple different apparatuses for
injecting purge gas 18 into chamber 36 could be simultaneously
provided. In this manner, multiple flow regimes could be produced
in a single deposition chamber apparatus.
[0044] In keeping with the variety of possible features in a
deposition chamber apparatus, the present inventions also encompass
a variety of deposition methods. In one aspect, a deposition method
includes injecting at least one deposition precursor into a
deposition chamber including a lid having an outer surface outside
the chamber and an inner chamber inside the chamber. While
injecting the precursor, the method can include separately
injecting a purge material through at least one purge passageway
through the lid from the outer surface to the inner surface. The
injected purge material can flow along at least a portion of the
chamber walls. Such a deposition method can be a CVD method, such
as ALD. The various purge and process chemical injection
apparatuses described above can be used in such a method to produce
the flow dynamics and advantages previously described. For example,
the deposition method can further include forming a curtain from
the injected purge material concentric to chamber walls, the
curtain flowing axially with respect to the chamber. Forming the
purge material curtain can include forming an annular curtain.
Also, the injecting the purge material can occur at a first flow
rate while injecting the precursor. The method can further include
ceasing the precursor injection and substituting the precursor
injection for additional purge material injection. Still further,
while the precursor injection is ceased, the method can include
adjusting the first flow rate to a second flow rate different from
the first flow rate.
[0045] In a further aspect of the present invention, a deposition
method can include injecting at least one deposition precursor into
a deposition chamber wherein the precursor delivery occurs through
at least one process chemical port in a lid of the chamber. The
method can include ceasing delivery of the precursor and delivering
purge material through at least one process chemical port. While
delivering the purge material through the process chemical port, a
purge material can be separately delivered through at least one
purge port in the lid. The purge delivery through the purge port
can occur along a part of the chamber walls. As an option, the
purge material injection through the purge port can be stopped
during the injecting the precursor through the process chemical
port.
[0046] As a still further aspect of the invention, a chemical vapor
deposition method can include injecting at least one purge material
into a deposition chamber defined at least in part by chamber
walls. A purge curtain can be formed from the injected purge
material, the purge curtain extending downward from elevationally
above a substrate holder and outside a lateral periphery of the
substrate holder. The purge curtain can flow past the substrate
holder. As an example, the purge curtain can extend from one of one
of the chamber walls comprising a lid. The purge curtain can also
be concentric to the substrate holder and flow axially with respect
to the substrate holder. An annular purge curtain is one example.
The method can further include injecting at least one process
chemical into the chamber from elevationally above the substrate
holder and inside a lateral periphery of the substrate holder. The
process chemical can be delivered to a substrate received by the
substrate holder.
[0047] As can be understood from the descriptions above, various
purge scenarios are encompassed by the aspects of the invention. A
few examples of possible purge scenarios are described in FIGS.
9-13 as pertaining to FIGS. 7 and 8. Such figures exemplify an ALD
process, however, the invention is not limited to ALD. FIG. 7 shows
flow rate of precursor A with respect to time. Although the time
intervals shown in the figures are equal, it is understood that
purge times and pulse times can vary between processes and from
cycle to cycle within a single process.
[0048] Precursor A is shown in FIG. 7 injected at flow rate A from
time 0 (T0) to time 1 (T1) and then stopped. A precursor purge is
shown in FIG. 9 occurring at flow rate C from T1 to T2 to purge
precursor A from process chemical inlets and the main space of the
deposition chamber. Precursor B is then injected at flow rate B
from T2 to T3, as shown in FIG. 8. Injection of precursor B is
followed by precursor purge at flow rate C from T3 to T4.
Accordingly, ALD of one monolayer occurs with completion of a first
cycle at T4. FIGS. 7-9 show a second cycle occurring from T4 to
T8.
[0049] FIGS. 10-13 show various alternatives in providing a curtain
purge along with the ALD process exemplified by FIGS. 7-9. In FIG.
10, a curtain purge is provided at flowrate D continuously from T0
to T8. Accordingly, a curtain is provided during injection of each
precursor as well as during precursor purge of the chamber. As a
slight variation on this flow scenario, FIG. 13 shows curtain purge
occurring at flowrate D during injection of precursors A and B, but
decreasing to flowrate E during precursor purge. The flow scenario
of FIG. 13 recognizes that, given the injection of precursor purge
at flowrate C, curtain purge might be reduced. In a similar manner,
FIG. 11 shows curtain purge occurring at flowrate D only during
injection of precursors A and B and no curtain purge during
precursor purge. Alternatively, FIG. 12 shows injection of curtain
purge at flowrate D only during injection of precursor purge and
not during injection of precursors A and B. In a circumstance where
injection of curtain purge negatively impacts a deposition process,
curtain purge can nevertheless be used to enhance removal of
materials from a deposition chamber during precursor purge.
Accordingly, the various benefits and advantages of the invention
described herein can be obtained using aspects of the invention
according to the above descriptions.
[0050] In compliance with the statute, the invention has been
described in language more or less specific as to structural and
methodical features. It is to be understood, however, that the
invention is not limited to the specific features shown and
described, since the means herein disclosed comprise preferred
forms of putting the invention into effect. The invention is,
therefore, claimed in any of its forms or modifications within the
proper scope of the appended claims appropriately interpreted in
accordance with the doctrine of equivalents.
* * * * *