U.S. patent application number 11/430492 was filed with the patent office on 2006-09-14 for methods and apparatus for processing microfeature workpieces, e.g., for depositing materials on microfeature workpieces.
This patent application is currently assigned to Micron Technology, Inc.. Invention is credited to Cem Basceri, Kevin L. Beaman, Lyle D. Breiner, Trung T. Doan, David J. Kubista, Er-Xuan Ping, Ronald A. Weimer, Lingyi A. Zheng.
Application Number | 20060205187 11/430492 |
Document ID | / |
Family ID | 34217652 |
Filed Date | 2006-09-14 |
United States Patent
Application |
20060205187 |
Kind Code |
A1 |
Zheng; Lingyi A. ; et
al. |
September 14, 2006 |
Methods and apparatus for processing microfeature workpieces, e.g.,
for depositing materials on microfeature workpieces
Abstract
The present disclosure suggests several systems and methods for
batch processing of microfeature workpieces, e.g., semiconductor
wafers or the like. One exemplary implementation provides a method
of depositing a reaction product on each of a batch of workpieces
positioned in a process chamber in a spaced-apart relationship. A
first gas may be delivered to an elongate first delivery conduit
that includes a plurality of outlets spaced along a length of the
conduit. A first gas flow may be directed by the outlets to flow
into at least one of the process spaces between adjacent workpieces
along a first vector that is transverse to the direction in which
the workpieces are spaced. A second gas may be delivered to an
elongate second delivery conduit that also has outlets spaced along
its length. A second gas flow of the second gas may be directed by
the outlets to flow into the process spaces along a second vector
that is transverse to the first direction.
Inventors: |
Zheng; Lingyi A.; (Manassas,
VA) ; Doan; Trung T.; (Vallejo, CA) ; Breiner;
Lyle D.; (Meridian, ID) ; Ping; Er-Xuan;
(Meridian, ID) ; Beaman; Kevin L.; (Boise, ID)
; Weimer; Ronald A.; (Boise, ID) ; Kubista; David
J.; (Nampa, ID) ; Basceri; Cem; (Reston,
VA) |
Correspondence
Address: |
PERKINS COIE LLP;PATENT-SEA
PO BOX 1247
SEATTLE
WA
98111-1247
US
|
Assignee: |
Micron Technology, Inc.
Boise
ID
|
Family ID: |
34217652 |
Appl. No.: |
11/430492 |
Filed: |
May 9, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10652461 |
Aug 28, 2003 |
|
|
|
11430492 |
May 9, 2006 |
|
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Current U.S.
Class: |
438/478 |
Current CPC
Class: |
C23C 16/45546 20130101;
C23C 16/45578 20130101; C23C 16/4583 20130101 |
Class at
Publication: |
438/478 |
International
Class: |
H01L 21/20 20060101
H01L021/20 |
Claims
1-29. (canceled)
30. A method of depositing a reaction product on each of a batch of
microfeature workpieces, comprising: positioning a plurality of
microfeature workpieces in a process chamber, the microfeature
workpieces being spaced from one another in a first direction to
define a process space between pairs of adjacent workpieces;
delivering a first gas to an elongate first delivery conduit that
has a length in the first direction and directing a first gas flow
of the first gas into at least one of the process spaces from a
plurality of outlets spaced in the first direction along the length
of the first delivery conduit, the individual first gas flows being
directed to flow along a first vector transverse to the first
direction; and after terminating the first gas flow, delivering a
second gas to an elongate second delivery conduit that has a length
in the first direction and directing a second gas flow of the
second gas into at least one of the process spaces from a plurality
of outlets spaced in the first direction along the length of the
second delivery conduit, the individual second gas flows being
directed to flow along a second vector transverse to the first
direction.
31. The method of claim 30 wherein the first vectors are transverse
to the second vectors.
32. The method of claim 30 wherein the first vectors are
substantially parallel to one another.
33. The method of claim 30 wherein the second vectors are
substantially parallel to one another.
34. The method of claim 30 wherein each of the first vectors and
the second vectors are directed inwardly toward a center of one of
the microfeature workpieces.
35. The method of claim 30 wherein the first gas comprises a first
reaction precursor and the second gas comprises a purge gas that is
different from the first reaction precursor.
36. The method of claim 30 wherein the first gas comprises a first
reaction precursor and the second gas comprises a second reaction
precursor that is adapted to react with the first reaction
precursor to form the reaction product.
37. (canceled)
38. The method of claim 30 further comprising: terminating the
first gas flow; exhausting the first gas from the process chamber;
and, thereafter, initiating the second gas flow.
39. The method of claim 30 further comprising: terminating the
first gas flow; delivering a purge gas to the process chamber and
exhausting the purge gas from the process chamber; and, thereafter,
initiating the second gas flow.
40. The method of claim 30 further comprising directing a third gas
flow of the first gas along a third vector that extends in the
first direction.
41. The method of claim 30 further comprising delivering a third
gas flow of the first gas to the process chamber while directing
the first gas flows, the third gas flow being directed to flow
along a third vector that extends in the first direction and is
transverse to the first gas flow.
42. The method of claim 41 further comprising delivering a fourth
gas flow of the second gas to the process chamber while directing
the second gas flows, the fourth gas flow being directed to flow
along a fourth vector that extends in the first direction and is
transverse to the second gas flow.
43. A method of depositing a reaction product on each of a batch of
microfeature workpieces, comprising: positioning a plurality of
microfeature workpieces in a process chamber, the microfeature
workpieces being spaced from one another in a first direction to
define a process space between pairs of adjacent workpieces;
delivering a first gas to an elongate first delivery conduit that
has a length in the first direction and directing a first gas flow
of the first gas into at least one of the process spaces from a
plurality of first outlets that are spaced in the first direction
along the length of the first delivery conduit, the individual
first gas flows being directed transverse to the first direction;
and delivering a second gas to a second delivery conduit and
directing a second gas flow of the second gas from a second outlet
in the first direction with the second outlet positioned at the
process chamber.
44. The method of claim 43 wherein the first gas comprises a first
reaction precursor and the second gas comprises a purge gas that is
different from the first reaction precursor.
45. The method of claim 43 wherein the first gas comprises a first
reaction precursor and the second gas comprises a second reaction
precursor that is configured to react with the first reaction
precursor to form the reaction product.
46. The method of claim 43, further comprising terminating the
first gas flow before initiating the second gas flow.
47. The method of claim 43, further comprising: terminating the
first gas flow; exhausting the first gas from the process chamber;
and, thereafter, initiating the second gas flow.
48. The method of claim 43, further comprising: terminating the
first gas flow; delivering a purge gas to the process chamber and
exhausting the purge gas from the process chamber; and, thereafter,
initiating the second gas flow.
49. The method of claim 43 wherein directing the first gas flow
occurs while directing the second gas flow.
50. The method of claim 43, further comprising delivering a third
gas to an elongate second delivery conduit that has a length in the
first direction and directing a third gas flow of the third gas
into at least one of the process spaces from a plurality of outlets
spaced in the first direction along the length of the second
delivery conduit, the individual third gas flows being directed to
flow along a second vector transverse to the first direction.
Description
TECHNICAL FIELD
[0001] The present invention is related to equipment and methods
for processing microfeature workpieces, e.g., semiconductor wafers.
Aspects of the invention have particular utility in connection with
batch deposition of materials on microfeature workpieces, such as
by atomic layer deposition or chemical vapor deposition.
BACKGROUND
[0002] Thin film deposition techniques are widely used in the
manufacturing of microfeatures to form a coating on a workpiece
that closely conforms to the surface topography. In the context of
microelectronic components, for example, the size of the individual
components in the devices on a wafer is constantly decreasing, and
the number of layers in the devices is increasing. As a result, the
density of components and the aspect ratios of depressions (e.g.,
the ratio of the depth to the size of the opening) are increasing.
The size of such wafers is also increasing to provide more real
estate for forming more dies (i.e., chips) on a single wafer. Many
fabricators are currently transitioning from 200 mm to 300 mm
workpieces, and even larger workpieces will likely be used in the
future. Thin film deposition techniques accordingly strive to
produce highly uniform conformal layers that cover the sidewalls,
bottoms, and corners in deep depressions that have very small
openings.
[0003] One widely used thin film deposition technique is chemical
vapor deposition (CVD). In a CVD system, one or more precursors
that are capable of reacting to form a solid thin film are mixed in
a gas or vapor state, and then the precursor mixture is presented
to the surface of the workpiece. The surface of the workpiece
catalyzes the reaction between the precursors to form a solid thin
film at the workpiece surface. A common way to catalyze the
reaction at the surface of the workpiece is to heat the workpiece
to a temperature that causes the reaction.
[0004] Although CVD techniques are useful in many applications,
they also have several drawbacks. For example, if the precursors
are not highly reactive, then a high workpiece temperature is
needed to achieve a reasonable deposition rate. Such high
temperatures are not typically desirable because heating the
workpiece can be detrimental to the structures and other materials
already formed on the workpiece. Implanted or doped materials, for
example, can migrate within silicon workpieces at higher
temperatures. On the other hand, if more reactive precursors are
used so that the workpiece temperature can be lower, then reactions
may occur prematurely in the gas phase before reaching the intended
surface of the workpiece. This is undesirable because the film
quality and uniformity may suffer, and also because it limits the
types of precursors that can be used.
[0005] Atomic layer deposition (ALD) is another thin film
deposition technique. FIGS. 1A and 1B schematically illustrate the
basic operation of ALD processes. Referring to FIG. 1A, a layer of
gas molecules A coats the surface of a workpiece W. The layer of A
molecules is formed by exposing the workpiece W to a precursor gas
containing A molecules, and then purging the chamber with a purge
gas to remove excess A molecules. This process can form a monolayer
of A molecules on the surface of the workpiece W because the A
molecules at the surface are held in place during the purge cycle
by physical adsorption forces at moderate temperatures or
chemisorption forces at higher temperatures. The layer of A
molecules is then exposed to another precursor gas containing B
molecules. The A molecules react with the B molecules to form an
extremely thin layer of solid material C on the workpiece W. The
chamber is then purged again with a purge gas to remove excess B
molecules.
[0006] FIG. 2 illustrates the stages of one cycle for forming a
thin solid layer using ALD techniques. A typical cycle includes (a)
exposing the workpiece to the first precursor A, (b) purging excess
A molecules, (c) exposing the workpiece to the second precursor B,
and then (d) purging excess B molecules. The purge process
typically comprises introducing a purge gas, which is substantially
nonreactive with either precursor, and exhausting the purge gas and
excess precursor from the reaction chamber in a pumping step. In
actual processing, several cycles are repeated to build a thin film
on a workpiece having the desired thickness. For example, each
cycle may form a layer having a thickness of approximately 0.5-1.0
.ANG., and thus it takes approximately 60-120 cycles to form a
solid layer having a thickness of approximately 60 .ANG..
[0007] One drawback of ALD processing is that it has a relatively
low throughput compared to CVD techniques. For example, ALD
processing typically takes several seconds to perform each
A-purge-B-purge cycle. This results in a total process time of
several minutes to form a single thin layer of only 60 .ANG.. In
contrast to ALD processing, CVD techniques only require about one
minute to form a 60 .ANG. thick layer. In single-wafer processing
chambers, ALD processes can be 500%-2000% longer than corresponding
single-wafer CVD processes. The low throughput of existing
single-wafer ALD techniques limits the utility of the technology in
its current state because the ALD process may be a bottleneck in
the overall manufacturing process.
[0008] One promising solution to increase the throughput of ALD
processing is processing a plurality of wafers (e.g., 20-250)
simultaneously in a batch process. FIG. 3 schematically illustrates
a conventional batch ALD reactor 10 having a processing enclosure
20 coupled to a gas supply 30 and a vacuum 40. The processing
enclosure 20 generally includes an outer wall 22 and an annular
liner 24. A platform 60 seals against the outer wall 22 or some
other part of the processing enclosure 20 via a seal 62 to define a
process chamber 25. Gas is introduced from the gas supply 30 to the
process chamber 25 by a gas nozzle 32 that introduces gas into a
main chamber 28 of the process chamber 25. Under influence of the
vacuum 40, the gas introduced via the gas nozzle 32 will flow
through the main chamber 28 and outwardly into an annular exhaust
26 to be drawn out with the vacuum 40. A plurality of workpieces W,
e.g., semiconductor wafers, may be held in the processing enclosure
20 in a workpiece holder 70. In operation, a heater 50 heats the
workpieces W to a desired temperature and the gas supply 30
delivers the first precursor A, the purge gas, and the second
precursor B as discussed above in connection with FIG. 2.
[0009] However, when depositing material simultaneously on a large
number of workpieces in an ALD reactor 10 such as that shown in
FIG. 3, it can be difficult to uniformly deposit the precursors A
and B across the surface of each of the workpieces W. Removing
excess precursor from the spaces between the workpieces W can also
be problematic. In an ALD reactor 10 such as that shown in FIG. 3,
diffusion is the primary mechanism for removing residual precursor
that is not chemisorbed on the surface of one of the workpieces.
This is not only a relatively slow process that significantly
reduces the throughput of the reactor 10, but it also may not
adequately remove residual precursor. As such, conventional batch
ALD reactors may have a low throughput and form nonuniform
films.
[0010] In U.S. Patent Application Publication 2003/0024477 (the
entirety of which is incorporated herein by reference), Okuda et
al. suggest a system that employs a large plenum extending along
the interior wall of a reaction tube. This plenum has a series of
slots along its length with the intention of flowing gas parallel
to the surfaces of the substrates treated in the tube. Although
Okuda et al. suggest that this system may be used in both CVD and
ALD applications, using such a system in ALD systems can be
problematic. If a second precursor is introduced into the plenum
before the first precursor is adequately purged from the plenum,
the two precursors may react within the plenum. As a consequence,
sufficient purge gas must be delivered to the plenum to adequately
clear the first precursor, which may require even longer purge
processes between delivery of the precursors. Such extended purges
will reduce throughput and increase manufacturing costs. Throughput
may be maintained by selecting less reactive precursors, but such
precursors may require higher workpiece temperatures or preclude
the use of some otherwise desirable precursors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIGS. 1A and 1B are schematic cross-sectional views of
stages in ALD processing in accordance with the prior art.
[0012] FIG. 2 is a graph illustrating a cycle for forming a layer
using ALD techniques in accordance with the prior art.
[0013] FIG. 3 is a schematic representation of a system including a
reactor for depositing a material onto a microfeature workpiece in
accordance with the prior art.
[0014] FIG. 4 is a schematic longitudinal cross-sectional view,
taken along line 4-4 of FIG. 5, of a microfeature workpiece
processing system in accordance with one embodiment of the
invention.
[0015] FIG. 5 is a schematic transverse cross-sectional view of the
microfeature workpiece processing system of FIG. 4, taken along
line 5-5 of FIG. 4.
[0016] FIG. 6 is a schematic transverse cross-sectional view of a
microfeature workpiece processing system in accordance with a
modified embodiment of the invention.
[0017] FIG. 7 is a schematic longitudinal cross-sectional view,
taken along line 7-7 of FIG. 8, of a microfeature workpiece
processing system in accordance with another embodiment of the
invention.
[0018] FIG. 8 is a schematic transverse cross-sectional view of the
microfeature workpiece processing system of FIG. 7, taken along the
line 8-8 in FIG. 7.
[0019] FIG. 9 is a schematic longitudinal cross-sectional view of a
microfeature workpiece processing system in accordance with still
another embodiment of the invention.
DETAILED DESCRIPTION
A. Overview
[0020] Various embodiments of the present invention provide
microfeature workpiece processing systems and methods for
depositing materials onto microfeature workpieces. Many specific
details of the invention are described below with reference to
exemplary systems for depositing materials onto microfeature
workpieces. The term "microfeature workpiece" is used throughout to
include substrates upon which and/or in which microelectronic
devices, micromechanical devices, data storage elements, read/write
components, and other features are fabricated. For example,
microfeature workpieces can be semiconductor wafers such as silicon
or gallium arsenide wafers, glass substrates, insulative
substrates, and many other types of materials. The microfeature
workpieces typically have submicron features with dimensions of
0.05 microns or greater. Furthermore, the term "gas" is used
throughout to include any form of matter that has no fixed shape
and will conform in volume to the space available, which
specifically includes vapors (i.e., a gas having a temperature less
than the critical temperature so that it may be liquefied or
solidified by compression at a constant temperature). Moreover, the
term "transverse" is used throughout to mean oblique,
perpendicular, and/or not parallel. Several embodiments in
accordance with the invention are set forth in FIGS. 4-9 and the
following text to provide a thorough understanding of particular
embodiments of the invention. A person skilled in the art will
understand, however, that the invention may have additional
embodiments, or that the invention may be practiced without several
of the details of the embodiments shown in FIGS. 4-9.
[0021] Some embodiments of the invention provide microfeature
workpiece processing systems. In one such embodiment, a
microfeature workpiece processing system includes a process
chamber, a first gas conduit, a second gas conduit, a first gas
supply line, and a second gas supply line. The process chamber has
a workpiece area adapted to receive a plurality of spaced-apart
microfeature workpieces arranged relative to a longitudinal axis of
the process chamber. The first gas conduit extends longitudinally
within the process chamber proximate the workpiece area. This first
gas conduit may have a plurality of first outlets spaced
longitudinally along a length of the first gas conduit. The first
outlets may be oriented toward the workpiece area and adapted to
direct a first gas flow transverse to the longitudinal axis. In one
embodiment, the second gas conduit may also extend longitudinally
within the process chamber proximate the workpiece area and include
a plurality of second outlets spaced longitudinally along a length
of the second gas conduit. The second outlets may be oriented
toward the workpiece area and adapted to direct the second gas flow
transverse to the longitudinal axis. The direction of the second
gas flow may be transverse to the direction of the first gas flow.
The first gas supply line may be adapted to deliver a first gas to
the first gas conduit, and the second gas supply line may be
adapted to deliver a second gas to the second gas conduit. The
second gas supply line may be independent of the first gas supply
line, and the second gas may be different from the first gas.
[0022] A microfeature workpiece processing system in accordance
with another embodiment of the invention includes a process
chamber, a first gas conduit, a second gas conduit, a first gas
supply line, and a second gas supply line. The process chamber may
be adapted to receive a plurality of transversely oriented
microfeature workpieces spaced from one another in a longitudinal
direction. The first gas conduit may extend longitudinally within
the process chamber and include a plurality of outlets spaced
longitudinally along a length of the first gas conduit; each of the
outlets is oriented to direct a first gas flow transversely across
a surface of one of the workpieces. The second gas conduit may have
a second outlet oriented to direct a second gas flow longitudinally
within the process chamber, e.g., generally perpendicular to the
direction of the first gas flow. The first gas supply line is
adapted to deliver a first gas to the first gas conduit, and the
second gas supply line is adapted to deliver a second gas to the
second gas conduit.
[0023] An alternative embodiment of the invention provides a method
of depositing a reaction product on each of a batch of microfeature
workpieces. In accordance with this method, a plurality of
workpieces may be positioned in the process chamber, with the
workpieces spaced from one another in a first direction to define a
process space between each pair of adjacent workpieces. A first gas
may be delivered to an elongate first delivery conduit that has a
length in the first direction and may direct a first gas flow of
the first gas into at least one of the process faces from each of a
plurality of outlets spaced in the first direction along the length
of the first delivery conduit. Each of the first gas flows is
directed to flow along a first vector transverse to the first
direction. A second gas may be delivered to an elongate second
delivery conduit that has a length in the first direction. A second
gas flow of the second gas may be directed into at least one of the
process spaces from each of a plurality of outlets spaced in the
first direction along the length of the second delivery conduit.
Each of the second gas flows may be directed to flow along a second
vector that is transverse to the first direction and may also be
transverse to the first vector.
[0024] An alternative embodiment of the invention provides a method
of depositing a reaction product that includes positioning a
plurality of microfeature workpieces similar to the previous
method. A first gas may be delivered to a first delivery conduit
and directed into process spaces between the workpieces as in the
prior embodiment. In this embodiment, however, a second gas is
delivered to a second delivery conduit and a second gas flow of the
second gas is directed in the first direction, which may be
substantially perpendicular to the first gas flow.
[0025] For ease of understanding, the following discussion is
subdivided into two areas of emphasis. The first section discusses
microfeature workpiece processing systems in accordance with
selected embodiments of the invention. The second section outlines
methods in accordance with other aspects of the invention.
B. Microfeature Workpiece Processing System
[0026] FIGS. 4 and 5 schematically illustrate a microfeature
workpiece processing system 100 in accordance with one embodiment
of the invention. The processing system 100 includes a reactor 110
adapted to receive a plurality of microfeature workpieces W, which
may be carried in a workpiece holder 70. The reactor 110 generally
includes an enclosure 120 defined by an outer wall 122 and a
platform 160 (FIG. 4) upon which the workpiece holder 70 may be
supported. The outer wall 122 may sealingly engage the platform 160
(schematically illustrated in FIG. 4 as an O-ring seal 162). This
will define a process chamber 125 within which the workpiece holder
70 and microfeature workpieces W may be received. In the embodiment
shown in FIG. 4, the workpieces W are positioned in a workpiece
area of the process chamber 125 that is substantially centered
about a longitudinal axis A of the process chamber 125.
[0027] This particular reactor 110 includes an annular liner 124
that may functionally divide the process chamber 125 into a main
chamber 128 and an annular exhaust 126. The annular exhaust 126 may
be in fluid communication with a vacuum 170, e.g., a vacuum pump,
via a vacuum line 172. During the pumping phase of the purge
process noted above in connection with FIG. 2, the vacuum 170 may
exhaust gas from the main chamber 128 via this annular exhaust
126.
[0028] The reactor 110 may also include a heater 150. The heater
150 can be any conventional design. In one exemplary embodiment,
the heater 150 may comprise an induction heater. Other suitable
heaters 150 for use in connection with particular processes to be
carried out in the processing system 100 will be readily apparent
to those skilled in the art.
[0029] The processing system 100 also includes a first gas conduit
140a and a second gas conduit 140b that extend longitudinally
within the main chamber 128 of the process chamber 125. The gas
conduits 140a-b are positioned proximate the workpiece area where
the workpieces W are received. Each of the gas conduits 140
includes a plurality of outlets 142 spaced longitudinally along its
length and oriented toward the workpieces W. In the illustrated
embodiment, the outlets 142 of each of the gas conduits 140 are
adapted to direct a flow of gas from one of the gas supplies 130a-c
(discussed below) transverse to the longitudinal axis A of the
process chamber 125. In one specific implementation, the outlets
142 may be oriented to direct a flow of gas perpendicular to this
axis A. The first and second gas conduits 140a and 140b may be
positioned within the main chamber 128 of the enclosure 120 in any
suitable relative orientation. In the illustrated embodiment, the
gas conduits 140a and 140b are substantially parallel to one
another and oriented at an angle less than 180 degrees from one
another. If so desired, the outlets 142 of the first gas conduit
140a may be oriented to direct a flow of gas generally parallel to
the direction in which the outlets 142 of the second gas conduit
140b direct the flow of gas from the second gas conduit 140b. In
the illustrated embodiment, the outlets 142 of the first gas
conduit 140a may direct a first gas flow along a flow vector
F.sub.1 (FIG. 5) oriented generally toward the longitudinal axis A
of the chamber 125, which may substantially coincide with the
center of each workpiece W. The outlets 142 of the second gas
conduit 140b may orient a second flow of gas along a second flow
vector F.sub.2 (FIG. 5) that is also oriented toward the
longitudinal axis A. These two flow vectors F.sub.1 and F.sub.2 may
be oriented transverse to one another. In CVD applications or in
the purge processes of ALD, such transverse flow may facilitate
high throughput without unduly compromising quality and
uniformity.
[0030] The outlets 142 can also be positioned relative to the
orientation of the workpieces W. The workpieces W are spaced apart
in the workpiece holder 70 and oriented generally parallel to one
another such that a process space S separates each pair of adjacent
workpieces W. The outlets 142 can be configured to direct a flow of
gas from respective gas conduit 140a or 140b transversely into each
process space S. As a consequence, a flow of gas can be established
transversely across a surface of each workpiece W. If the gas
conduits 140a and 140b are used to deliver precursor gases in an
ALD or CVD process, this transverse flow through the process spaces
and across the surfaces of the workpieces W is expected to enhance
the uniformity of material deposition on the surfaces of the
workpieces W. If a purge gas is delivered through one or both of
the gas conduits 140a and 140b, this transverse flow of gas along
the flow vectors F.sub.1 and/or F.sub.2 can efficiently purge the
process spaces S of any excess precursor gas.
[0031] The processing system 100 also includes at least two gas
supplies. In particular, a first gas supply 130a of a first gas
(GAS.sub.1) is coupled to the first gas conduit 140a by a first gas
supply line 132a. Similarly, a second gas supply 130b of a second
gas (GAS.sub.2) is coupled to the second gas conduit 140b by a
second gas supply line 132b. If so desired, a first gas supply
valve 134a may be provided in the first gas supply line 132a and a
second gas supply valve 134b may be provided in the second gas
supply line 132b. The processing system 100 may also include a
third gas supply 130c adapted to provide a third gas (GAS.sub.3),
e.g., a purge gas, via a third gas supply line 132c. The third gas
supply line 132c may be in fluid communication with the first gas
supply line 132a and/or the second gas supply line 132b. This would
permit delivery of the third gas (GAS.sub.3) from the third gas
supply line 130c to the process chamber 125 via one or both of the
gas conduits 140a and 140b. A third gas supply valve 134c may be
provided in the third gas supply line 132c.
[0032] The gas supply valves 134a-c may be operated to selectively
introduce the desired process gas (e.g., GAS.sub.1, GAS.sub.2,
GAS.sub.3) under the direction of a controller 180. In one
embodiment, the controller 180 comprises a computer having a
programmable processor programmed to control operation of the
processing system 100 to deposit material on the workpieces W. The
controller 180 may be coupled to the vacuum 170 to control its
operation. The controller 180 may also be operatively connected to
the heater 150 to control the temperature of the workpieces W
and/or an actuator (not shown) to move the platform 160 toward or
away from the outer wall 122, as suggested by the arrow L, to allow
the workpieces W to be loaded into or moved from the process
chamber 125.
[0033] The composition of the gases in the gas supplies 130a-c can
be varied depending on the process to be carried out in the
processing system 100. If the processing system 100 is used in an
ALD process, for example, the first gas supply 130a may contain a
first precursor (e.g., precursor A discussed above in FIGS. 1 and
2) and the second gas supply 130b may contain a second precursor
(e.g., precursor B in FIGS. 1 and 2). The reaction tube suggested
by Okuda et al. in U.S. Patent Application Publication US
2003/0024477 delivers all the gases to a relatively large common
plenum. As discussed above, this plenum arrangement can have a
number of disadvantages, including longer purge times, decreased
throughput, and increased manufacturing costs. In contrast, the
microfeature workpiece processing system 100 of FIGS. 4 and 5 may
deliver the reaction precursors through separate gas conduits 140.
Using separate gas conduits 140 permits a transverse flow of gas
through the process spaces S to enhance product uniformity and
throughput, but avoids the problems expected to be encountered in a
system that employs a single common plenum such as that suggested
by Okuda et al.
[0034] FIG. 6 schematically illustrates a microfeature workpiece
processing system 102 in accordance with another embodiment of the
invention. This processing system 102 may be similar in many
respects to the processing system 100 of FIGS. 4 and 5 and like
reference numbers are used to indicate like elements in FIGS. 4-6.
The processing system 100 of FIGS. 4 and 5 includes a single first
gas conduit 140a and a single second gas conduit 140b, each of
which is adapted to deliver a separate gas, i.e., GAS.sub.1 or
GAS.sub.2, respectively. The processing system 102 of FIG. 6,
however, includes several first gas conduits 140a and several
second gas conduits 140b. In the specific implementation shown in
this figure, three first gas conduits 140a are spaced approximately
equiangularly about the periphery of the workpiece area where the
workpieces W are received. Each of the first gas conduits 140a is
adapted to direct a flow of gas along a flow vector F.sub.1 that is
oriented toward and perpendicular to the longitudinal axis A of the
process chamber (125 in FIG. 4). As a consequence, each of the
first gas flow vectors F.sub.1 are transverse to one another, as
well. The three second gas conduits 104b of FIG. 6 also may be
spaced approximately equiangularly about the periphery of the
workpiece area. Each of the second gas conduits 140b is adapted to
direct a second flow of gas along a second gas flow vector F.sub.2
that is oriented toward and perpendicular to the longitudinal axis
A of the process chamber 125 and transverse to one another. It is
anticipated that the use of multiple flow vectors for each gas
supply can further enhance uniformity of gas distribution across
the surfaces of the workpieces W.
[0035] FIGS. 7 and 8 illustrate a microfeature workpiece processing
system 200 in accordance with another embodiment of the invention.
Many of the elements of the processing system 200 may be
substantially the same as elements of the processing system 100 of
FIGS. 4 and 5 and like reference numbers are used in both pairs of
drawings to indicate like elements.
[0036] The microfeature workpiece processing system 200 of FIGS. 7
and 8 includes a single longitudinally extending gas conduit 240
deposed within the main chamber 128 of the enclosure 120. A number
of outlets 242 may be spaced longitudinally along a length of the
gas conduit 240, with at least one outlet 242 associated with each
process space S defined by the workpieces W. The construction and
orientation of the gas conduit 240 may be substantially the same as
that of the first or second gas conduit 140a or 140b of FIGS. 4 and
5. As a consequence, the outlets 242 of the gas conduit 240 are
adapted to direct a flow of gas along a transverse flow vector
F.sub.T, which may be oriented generally toward the center of an
associated process space S and generally perpendicular to the
longitudinal axis A of the process chamber 125.
[0037] The specific microfeature workpiece processing system 200
shown in FIGS. 7 and 8 includes the single gas conduit 240. It
should be understood, though, that any number of gas conduits 240
may be employed. By analogy to the plurality of first gas conduits
140a in FIG. 6, for example, a series of gas conduits 240 having a
common gas supply (discussed below) may be spaced about the
periphery of the workpiece area.
[0038] In addition to the gas conduit 240, the processing system
200 of FIGS. 7 and 8 includes one or more longitudinal conduits or
nozzles 250 adapted to direct a flow of gas along a longitudinally
oriented flow vector F.sub.L. This flow vector F.sub.L may be
substantially parallel to the longitudinal axis A of the process
chamber 125 and generally perpendicular to the transverse flow
vectors F.sub.T from the outlets 242 of the gas conduit 240. In one
embodiment, a single longitudinal nozzle 250 is positioned in the
main chamber 128 of the enclosure 120. As best seen in FIG. 8,
though, the illustrated embodiment utilizes a number of
longitudinal nozzles 250 arranged peripherally about the workpiece
area in which the workpieces W are received. The particular
implementation shown in FIG. 8 positions five longitudinal nozzles
250 substantially equiangularly about this periphery, but any
suitable number of longitudinal nozzles 250 may be employed.
[0039] The microfeature workpiece processing system 200 of FIGS. 7
and 8 includes a plurality of gas supplies 230a, 230b, and 230c
coupled to a common gas supply manifold 236. A separate gas supply
valve 234a, 234b, or 234c may be associated with each of the gas
supplies 230a, 230b, and 230c, respectively. These gas supply
valves 234 may be operatively coupled to the controller 180 to
control the flow of gas through the common gas supply manifold 236.
The common gas supply manifold 236 may deliver a gas from one or
more of the gas supplies 230a-c to the longitudinally extending gas
conduit(s) 240 and the longitudinal nozzle(s) 250. When the
controller 180 opens one or more of the gas supply valves 234a-c, a
gas can be delivered through the common gas supply manifold 236
simultaneously to the gas conduit 240 and each of the longitudinal
nozzles 250. This can enhance the bulk flow rate of the desired gas
into the main chamber 128 of the enclosure 120 while establishing
sufficient transverse flow of the gas through the process spaces S
to achieve the necessary uniformity of gas distribution across the
surfaces of the workpieces W or an appropriately swift purging of
the process spaces S.
[0040] FIG. 9 schematically illustrates a microfeature workpiece
processing system 300 in accordance with yet another embodiment of
the invention. Many of the elements of this processing system 300
may be substantially the same as the elements of the processing
system 200 shown in FIG. 7; like reference numbers are used in
FIGS. 7 and 9 to indicate like elements.
[0041] One difference between the processing systems 200 and 300 of
FIGS. 7 and 9 relates to the gas supply. In the embodiment shown in
FIG. 7, the gas conduit 240 and the longitudinal nozzles 250 share
a common gas supply manifold 236. In the embodiment shown in FIG.
9, the longitudinal nozzle(s) 250 is in fluid communication with a
gas supply manifold 336. This gas supply manifold 336 is coupled to
a first gas supply 330a by a first gas supply valve 334a and a
second gas supply 330b by a second gas supply valve 334b. The gas
supply valves 334a and 334b are operatively connected to the
controller 180 to control the composition and flow rate of gas
delivered to the longitudinal nozzle(s) 250.
[0042] The longitudinally extending gas conduit 240 is connected to
an independent gas supply 330c via a third gas supply line 332c. A
third gas supply valve 334c may be operatively connected to the
controller 180 to control the flow of the third gas (GAS.sub.3)
delivered to the gas conduit 240.
[0043] The composition of the gasses (GAS.sub.1, GAS.sub.2, and
GAS.sub.3) can be varied to achieve different process objectives.
In one embodiment, the first gas supply 330a contains a first
precursor A, the second gas supply 330b contains a second precursor
B, and the third gas supply 330c includes a purge gas. This enables
the precursors A and B to be delivered to the main chamber 128 of
the enclosure 120 in a relatively conventional fashion. Delivering
the purge gas (GAS.sub.3) transversely through the outlets 242 can
fairly rapidly purge any excess precursor in the process spaces S
between the workpieces W. In contrast with the conventional ALD
reactor 10 shown in FIG. 3, which relies primarily on diffusion to
purge excess precursor from the process spaces S, the transverse
flow of purge gas through the process spaces S can significantly
reduce the time needed to conduct the purge cycle without adversely
affecting quality of the deposited material.
C. Methods of Depositing Materials on Microfeature Workpieces
[0044] As noted above, other embodiments of the invention provide
methods of processing microfeature workpieces. In the following
discussion, reference is made to the particular microfeature
workpiece processing system 100 shown in FIGS. 4 and 5. It should
be understood, though, that reference to this particular processing
system is solely for purposes of illustration and that the methods
outlined below are not limited to any particular processing system
shown in the drawings or discussed in detail above. In addition,
the following discussion focuses primarily on ALD. It should be
recognized, however, that the processes outlined below are not
limited to ALD and may have utility in CVD applications and in
connection with processes other than material deposition.
[0045] One embodiment of the invention provides a method of
depositing a reaction product on each of a batch of microfeature
workpieces. A plurality of microfeature workpieces W may be
positioned in a workplace area of the process chamber 125. In one
embodiment, the workpieces W are held by a workpiece holder 70 in a
spaced-apart relationship. In the embodiments illustrated above,
the workpiece holder 70 orients the workpieces W generally
perpendicular to the longitudinal axis A of the process chamber
125, defining a series of transversely oriented process spaces S
between the workpieces W.
[0046] A first gas may be delivered to the process chamber 125.
Using the processing system 100 of FIG. 4 as an example, the first
gas (GAS.sub.1) may be delivered from the first gas supply 130a to
the first gas conduit 140a by the first gas supply line 132a. This
may be accomplished by the controller 180 sending a signal to open
the first gas supply valve 134a. The first gas (GAS.sub.1) is
delivered transversely into the processing spaces S along a series
of generally parallel first transverse flow vectors F.sub.1. This
first gas (GAS.sub.1) may comprise a first precursor for the ALD
reaction. Once a sufficient quantity of this precursor is delivered
to the process spaces S to chemisorb a layer of the precursor on
the surface of the workpiece W, the first gas supply valve 134a may
be closed by the controller 180. Thereafter, a purge gas
(GAS.sub.3) can be delivered through the first gas conduit 140a
and/or the second gas conduit 140b. This transverse flow of purge
gas through the process spaces S will fairly rapidly remove any
excess precursor from the process spaces S. Either during the
delivery of the purge gas or after the flow of the purge gas is
terminated by closing the third gas supply valve 134c, the vacuum
170 may be actuated to exhaust gas from the process chamber 125 via
the annular exhaust 126. The vacuum 170 can continue to operate
after the third gas supply valve 134c is closed by the controller
180 until a desired reduced pressure is achieved.
[0047] The controller 180 may open the second gas supply valve 134b
to deliver a second precursor gas (GAS.sub.2) from the second gas
supply 130b via the second gas conduit 140b. The outlets 142 of the
second gas conduit 140b will deliver a transverse flow of this
second precursor to the process spaces S, facilitating reaction
with the previously chemisorbed first precursor to yield the
desired reaction product. After a sufficient quantity of the second
precursor gas (GAS.sub.2) is delivered to the process chamber 125,
the process chamber 125 may again be purged by delivering the purge
gas (GAS.sub.3) and pumping down the process chamber 125 using the
vacuum 170. This process can be repeated as many times as necessary
to achieve a layer of material on the surfaces of the workpieces W
having the desired thickness.
[0048] Unless the context clearly requires otherwise, throughout
the description and the claims, the words "comprise," "comprising,"
and the like are to be construed in an inclusive sense as opposed
to an exclusive or exhaustive sense, that is to say, in a sense of
"including, but not limited to." Words using the singular or plural
number also include the plural or singular number, respectively.
When the claims use the word "or" in reference to a list of two or
more items, that word covers all of the following interpretations
of the word any of the items in the list, all of the items in the
list, and any combination of the items in the list.
[0049] The above-detailed descriptions of embodiments of the
invention are not intended to be exhaustive or to limit the
invention to the precise form disclosed above. While specific
embodiments of, and examples for, the invention are described above
for illustrative purposes, various equivalent modifications are
possible within the scope of the invention, as those skilled in the
relevant art will recognize. For example, whereas steps are
presented in a given order, alternative embodiments may perform
steps in a different order. The various embodiments described
herein can be combined to provide further embodiments.
[0050] In general, the terms used in the following claims should
not be construed to limit the invention to the specific embodiments
disclosed in the specification, unless the above-detailed
description explicitly defines such terms. While certain aspects of
the invention are presented below in certain claim forms, the
inventors contemplate the various aspects of the invention in any
number of claim forms. Accordingly, the inventors reserve the right
to add additional claims after filing the application to pursue
such additional claim forms for other aspects of the invention.
* * * * *