U.S. patent application number 11/416866 was filed with the patent office on 2006-09-07 for microfeature workpiece processing apparatus and methods for batch deposition of 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 | 20060198955 11/416866 |
Document ID | / |
Family ID | 34194571 |
Filed Date | 2006-09-07 |
United States Patent
Application |
20060198955 |
Kind Code |
A1 |
Zheng; Lingyi A. ; et
al. |
September 7, 2006 |
Microfeature workpiece processing apparatus and methods for batch
deposition of materials on microfeature workpieces
Abstract
The present disclosure describes apparatus and methods for
processing microfeature workpieces, e.g., by depositing material on
a microelectronic semiconductor using atomic layer deposition. Some
of these apparatus include microfeature workpiece holders that
include gas distributors. One exemplary implementation provides a
microfeature workpiece holder adapted to hold a plurality of
microfeature workpieces. This workpiece holder includes a plurality
of workpiece supports and a gas distributor. The workpiece supports
are adapted to support a plurality of microfeature workpieces in a
spaced-apart relationship to define a process space adjacent a
surface of each microfeature workpiece. The gas distributor
includes an inlet and a plurality of outlets, with each of the
outlets positioned to direct a flow of process gas into one of the
process spaces.
Inventors: |
Zheng; Lingyi A.; (Manassas,
VA) ; Doan; Trung T.; (Vallejo, CA) ; Breiner;
Lyle D.; (Meridian, ID) ; Ping; Er-Xuan;
(Meridian, ID) ; Weimer; Ronald A.; (Boise,
ID) ; Kubista; David J.; (Nampa, ID) ; Beaman;
Kevin L.; (Boise, 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: |
34194571 |
Appl. No.: |
11/416866 |
Filed: |
May 3, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10646607 |
Aug 21, 2003 |
|
|
|
11416866 |
May 3, 2006 |
|
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Current U.S.
Class: |
427/248.1 ;
118/715; 118/728 |
Current CPC
Class: |
C23C 16/45546 20130101;
C23C 16/4583 20130101; C23C 16/45578 20130101; Y10S 206/832
20130101 |
Class at
Publication: |
427/248.1 ;
118/715; 118/728 |
International
Class: |
C23C 16/00 20060101
C23C016/00 |
Claims
1-43. (canceled)
44. A method of processing microfeature workpieces, comprising:
positioning a microfeature workpiece holder in a process chamber,
the microfeature workpiece holder supporting first, second and
third microfeature workpieces in a spaced-apart relationship to
define a first process space between the first and second
microfeature workpieces and define a second process space between
the second and third microfeature workpieces; delivering a first
process gas to the microfeature workpiece holder, the microfeature
workpiece holder carrying a gas distributor that delivers a first
flow of the first process gas transversely into the first process
space and delivers a second flow of the first process gas
transversely into the second process space; delivering a second
process gas to the process chamber; and removing the microfeature
workpiece holder and the microfeature workpieces from the process
chamber.
45. The method of claim 44 positioning the microfeature workpiece
holder in the process chamber comprises placing the microfeature
workpiece holder in an enclosure and substantially sealing the
enclosure to define the process chamber.
46. The method of claim 44 wherein delivering the second process
gas to the process chamber comprises delivering the second process
gas directly to the process chamber through a delivery conduit
independent of the gas distributor.
47. The method of claim 44 wherein delivering the second process
gas to the process chamber comprises delivering the second process
gas to the microfeature workpiece holder and delivering a first
flow of the second process gas transversely into the first process
space via the gas distributor and delivering a second flow of the
second process gas transversely into the second process space via
the gas distributor.
48. The method of claim 44 wherein the gas distributor includes a
first gas delivery conduit and an independent second gas delivery
conduit, and wherein delivering the first process gas to the
microfeature workpiece holder comprises delivering the first
process gas to the first conduit and delivering the second process
gas to the process chamber comprises delivering the second process
gas to the second gas delivery conduit.
49. The method of claim 48 wherein the second gas delivery conduit
delivers a first flow of the second process gas transversely into
the first process space and delivers a second flow of the second
process gas transversely into the second process space.
50. The method of claim 44 wherein the gas distributor includes a
gas delivery conduit, and wherein the first flow of the first
process gas is delivered through the gas delivery conduit to a
first outlet that directs the first process gas into the first
process space and the second flow of the first process gas is
delivered through the gas delivery conduit to a second outlet that
directs the first process gas into the second process space.
51. The method of claim 50 wherein the gas distributor includes a
first gas delivery conduit and a second gas delivery conduit, and
wherein: the first flow of the first process gas is delivered
through the gas delivery conduit to a first outlet that directs the
first process gas into the first process space; the second flow of
the first process gas is delivered through the gas delivery conduit
to a second outlet that directs the first process gas into the
second process space; and delivering the second process gas to the
process chamber comprises: delivering a first flow of the second
process gas through the second gas delivery conduit to a third
outlet that directs the second process gas transversely into the
first process space; and delivering a second flow of the second
process gas through the second gas delivery conduit to a fourth
outlet that directs the second process gas transversely into the
second process space.
52. A method of depositing a material on microfeature workpieces,
comprising: positioning a microfeature workpiece holder in a
process chamber, the microfeature workpiece holder supporting
first, second, and third microfeature workpieces in a spaced-apart
relationship to define a first process space between the first and
second microfeature workpieces and define a second process space
between the second and third microfeature workpieces; delivering a
first precursor gas to the process chamber to deposit a quantity of
the first precursor gas on a surface of each of the first, second,
and third microfeature workpieces; delivering a purge gas to the
microfeature workpiece holder, the microfeature workpiece holder
carrying a gas distributor that delivers a first flow of the purge
gas transversely into the first process space and delivers a second
flow of the purge gas transversely into the second process space;
delivering a second precursor gas to the process chamber, the
second precursor gas reacting with the quantity of the first
precursor gas to form a layer of material on the surfaces of the
first, second, and third microfeature workpieces; and removing the
microfeature workpiece holder and the microfeature workpieces from
the process chamber.
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
non-reactive 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 ALD 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 or some other
part of the 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 the 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 the annular exhaust 26 to be drawn
out with a vacuum 40. A plurality of workpieces W, e.g.,
semiconductor wafers, may be held in the processing enclosure 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 such as that shown in FIG. 3, the
primary mechanism for removing residual precursor that is not
chemisorbed on the surface of one of the workpieces is diffusion.
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 non-uniform
films.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIGS. 1A and 1B are schematic cross-sectional views of
stages in ALD processing in accordance with the prior art.
[0011] FIG. 2 is a graph illustrating a cycle for forming a layer
using ALD techniques in accordance with the prior art.
[0012] 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.
[0013] FIG. 4 is an isometric view of a microfeature workpiece
holder in accordance with one embodiment of the invention.
[0014] FIG. 5 is a side elevation view of the microfeature
workpiece holder of FIG. 4.
[0015] FIG. 6 is a schematic cross-sectional view of the
microfeature workpiece holder of FIGS. 4 and 5 taken along line 6-6
of FIG. 5.
[0016] FIG. 7 is a schematic cross-sectional view of the
microfeature workpiece holder of FIGS. 4-6 taken along line 7-7 of
FIG. 6.
[0017] FIG. 8 is a schematic cross-sectional view of the
microfeature workpiece holder of FIGS. 4-7 taken along line 8-8 of
FIG. 6.
[0018] FIG. 9 is a schematic side elevation view of a microfeature
workpiece holder in accordance with another embodiment of the
invention.
[0019] FIG. 10 is a schematic isometric view of a microfeature
workpiece holder in accordance with yet another embodiment of the
invention.
[0020] FIG. 11 is a schematic side elevation view of the
microfeature workpiece holder of FIG. 10.
[0021] FIG. 12 is a schematic cross-sectional view of the
microfeature workpiece holder of FIGS. 10 and 11 taken along line
12-12 of FIG. 11.
[0022] FIG. 13 is a schematic cross-sectional view of a portion of
the microfeature workpiece holder of FIGS. 10-12 taken along line
13-13 of FIG. 12.
[0023] FIG. 14 is a schematic cross-sectional view of a portion of
microfeature workpiece holder of FIGS. 10-13 taken along line 14-14
of FIG. 12.
[0024] FIG. 15 is a schematic illustration of a microfeature
workpiece processing system in accordance with a further embodiment
of the invention.
[0025] FIG. 16 is a schematic illustration of a microfeature
workpiece processing system in accordance with another embodiment
of the invention.
[0026] FIG. 17 is a schematic illustration of a microfeature
workpiece processing system in accordance with yet another
embodiment of the invention.
DETAILED DESCRIPTION
A. Overview
[0027] Various embodiments of the present invention provide
microfeature workpiece holders, systems including processing
chambers, and methods for depositing materials onto microfeature
workpieces. Many specific details of the invention are described
below with reference to reactors 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 devices 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). Several
embodiments in accordance with the invention are set forth in FIGS.
4-17 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.
4-17.
[0028] Certain embodiments of the invention provide microfeature
workpiece holders that are adapted to hold a plurality of
microfeature workpieces, e.g., for chemical processing such as ALD.
These workpiece holders may include a gas distributor comprising
one or more gas delivery conduits. The gas delivery conduit may
have an inlet and a plurality of outlets, which may be positioned
to direct a flow of process gas into the spaces between the
workpieces. This can facilitate more uniform distribution of
reaction precursors on a microfeature workpiece surface, for
example. The distribution of these outlets may also facilitate
rapid and effective purging of the space between the
workpieces.
[0029] Other embodiments of the invention provide microfeature
workpiece processing systems that may include an enclosure defining
a process chamber, a removable microfeature workpiece holder
disposed in the processing chamber, and a process gas supply
conduit. The workpiece holder may be similar to the workpiece
holders described above and include a gas distributor having
outlets adapted to direct a flow of gas from the process gas supply
between the microfeature workpieces.
[0030] Other embodiments of the invention provide methods of
depositing materials on microfeature workpieces. Although a number
of methods are described below, one method having particular
utility in connection with ALD includes positioning a microfeature
workpiece holder in a process chamber, with the microfeature
workpiece holder supporting a plurality of workpieces to define
process spaces between each pair of adjacent workpieces. A first
precursor gas may be delivered to the process chamber to deposit a
quantity of the first precursor gas on a surface of each of the
microfeature workpieces. A purge gas may be delivered to the
microfeature workpiece holder. The microfeature workpiece holder
may carry a gas distributor that delivers a first flow of the purge
gas transversely into the space between a pair of workpieces and
delivers a second flow of the purge gas transversely into a process
space between another pair of workpieces. The method may further
include delivering a second precursor gas to the process chamber;
the second precursor gas reacts with the quantity of the first
precursor gas to form a layer of material on the surfaces of the
workpieces.
[0031] For ease of understanding, the following discussion is
subdivided into three areas of emphasis. The first section
discusses microfeature workpiece holders in accordance with
selected embodiments of the invention. The second section describes
aspects of microfeature workpiece processing systems in other
embodiments of the invention. The third section discusses outlines
methods in accordance with other aspects of the invention.
B. Microfeature Workpiece Holders
[0032] FIGS. 4-8 schematically illustrate a microfeature workpiece
holder 100 in accordance with one embodiment of the invention. This
microfeature workpiece holder 100 generally includes a base, a
plurality of columns 120, and a cap 150. The particular embodiment
shown in FIGS. 4-8 employs 3 columns, namely columns 120a, 120b and
120c. The base 110 and the cap 150 are each generally semicircular
in shape and the columns 120a-c are spaced approximately 90.degree.
from one another so that the two outer columns 120a and 120c are
generally diametrically opposed to one another. It should be
recognized that this is simply one possible embodiment that may be
useful in connection with microfeature workpieces that are
generally circular in shape. In other embodiments, more or fewer
columns 120 may be employed. In addition, the base 110 and/or the
cap 150 may take the form of a solid plate or disk or have any
other desired shape. In other embodiments, only one of the base 110
or cap 150 is employed. For example, the cap 150 may be omitted and
the base 110 may provide the requisite support for the columns
120.
[0033] Each of the columns 120 in the microfeature workpiece holder
100 is generally circular in cross-section. In other embodiments,
the columns may have other shapes. For example, the columns 120 may
be generally wedge-shaped, such as those suggested in PCT
International Publication No. WO 02/095807 entitled, "Silicon
Fixtures Useful for High Temperature Wafer Processing," the
teachings of which are incorporated herein by reference.
[0034] Each of the columns 120 includes a plurality of workpiece
supports spaced longitudinally along its length. In the illustrated
embodiment, these workpiece supports comprise slots 122 that extend
into the body of the column 120. In other embodiments, the
workpiece holders may comprise inwardly-extending fingers, rings,
clamps, or other workpiece-supporting structures known in the art,
e.g., supports used in semiconductor wafer handling and processing
equipment. FIGS. 4 and 5 show columns with a limited number of
slots 122. Depending on the application in which the workpiece
holder 100 is used, the columns 120 may include fewer or more
slots.
[0035] The size and shape of the slots 122 can be modified as
desired. In one embodiment, each of the slots 122 is adapted to
receive an edge portion of one of the microfeature workpieces (as
suggested in FIG. 5). A single slot 122 may not be deep enough to
receive a sufficient portion of a microfeature workpiece W to
support the workpiece W. In the illustrated embodiment, the slots
122 on each of the columns 120a-c are positioned relative to one
another to cooperatively support the workpieces W. As illustrated
in FIG. 5, each slot 122 may be generally horizontally aligned with
a corresponding one of the slots 122 on each of the other two
columns 120. This permits a workpiece W to be supported at three
separate peripheral locations to enhance the support of each of the
workpieces W. If these slots 122 are spaced the same distance along
the length of each of the columns 120, the slots 122 may support a
plurality of microfeature workpieces W in a spaced-apart, generally
parallel relationship. The spaced-apart relationship of the
workpieces W will define a process space S between each of the
workpieces W.
[0036] As shown schematically in FIG. 5, the microfeature workpiece
holder 100 also includes a gas distributor 130. This gas
distributor 130 includes at least one gas delivery conduit 134
adapted to direct a flow of process gas relative to the workpieces
W. In one embodiment, a single gas delivery conduit 134 is
employed. In the particular embodiment shown schematically in FIG.
5, the gas distributor 130 includes a manifold 132 connecting a
plurality of gas delivery conduits 134a-c. The manifold 132 may
comprise an arcuate fluid passageway formed in the arcuate base 110
that provides fluid communication between a gas inlet 140 in the
base 110 and each of the gas delivery conduits 134a-c. In the
illustrated embodiment, a separate gas delivery conduit 134 is
associated with each of the columns 120. Hence, a first gas
delivery conduit 134a is carried by the first column 120a, a second
gas delivery conduit 134b is carried by a second column 120b, and a
third gas delivery conduit 134c is carried by the third column
120c. In some embodiments, one or more of the columns 120 may not
include a gas delivery conduit 134. In other embodiments, more than
one gas delivery conduit 134 may be carried by each column 120.
[0037] As best seen in FIGS. 6-8, the gas delivery conduit 134b may
comprise an internal lumen formed in the second column 120b.
(Although FIGS. 6-8 only illustrate the second column 120b, the
structure of the other columns 120a and 120c may be substantially
the same. Hence, the following discussion generically refers to a
column 120 and a gas delivery conduit 134.) The gas delivery
conduit 134 includes a plurality of transverse passages 136, each
of which directs fluid from the gas delivery conduit 134 to one of
a plurality of outlets 138. These outlets 138 are disposed between
two adjacent slots 122. The gas delivery conduit 134, including
each of the transverse passages 136 is generally circular in
cross-section and the outlets 138 define generally circular
openings. The size and shape of the gas delivery conduits 134 and
outlets 138 in the microfeature workpiece holder 100 can be varied,
though. In other embodiments, for example, the outlets 138 may
comprise ellipses or slots having a transverse dimension longer
than a longitudinal dimension or include a directional nozzle (not
shown).
[0038] When the microfeature workpieces W are loaded in the
microfeature workpiece holder 100, they will define a series of
process spaces S. At least one outlet 138 is desirably associated
with each of these process spaces S. In the illustrated embodiment,
one outlet 138 is positioned between each pair of adjacent slots
122 on each of the columns 120a-c. As a consequence, three outlets
138 are associated with each process space, with one outlet being
associated with each of the columns 120a-c supporting the
workpieces W. Directing transverse gas flows into the processing
spaces S can further enhance the flow of process gas from the gas
distributor 130 into and through the processing spaces S.
[0039] Referring back to FIG. 4, each of the outlets 138 may be
directed inwardly toward a central axis A (in FIG. 4) of the
microfeature workpiece holder 100. Consequently, when the
workpieces W are positioned in the holder 100, each of the outlets
138 will be positioned to direct a flow of process gas inwardly
toward a center of one of the workpieces W. This is expected to
further enhance the uniformity of material deposition and/or
decrease the time needed to purge the system.
[0040] The microfeature workpiece holder 100 can be formed of any
material that is suitable in light of the microfeature workpieces W
with which it will be used and the anticipated conditions of use.
If the microfeature workpieces W comprise semiconductor wafers, for
example, the microfeature workpiece holder 100 may be formed from
glass, fused silica (e.g., fused quartz), or polysilicon (i.e.,
polycrystalline silicon), among other materials. For other types of
applications that may be less sensitive to contamination, the
microfeature workpiece holder 100 may be formed of a metal, a
ceramic, or a suitably stiff and durable polymeric material.
[0041] FIG. 9 schematically illustrates a microfeature workpiece
holder 102 in accordance with another embodiment of the invention.
This microfeature workpiece holder 102 is similar in many respects
to the microfeature workpiece holder 100 shown in FIGS. 4-8 and
like reference numbers are used in FIGS. 4-9 to illustrate like
elements.
[0042] One difference between the microfeature workpiece holders
100 and 102 relates to the design of the gas distributor. The gas
distributor 130 shown in FIG. 5 employs a single gas inlet 140 that
communicates with each of the gas delivery conduits 134a-c through
a common manifold 132. The microfeature workpiece holder 102 of
FIG. 9 does not include a manifold 132. Instead, the gas
distributor 131 in FIG. 9 has a separate gas inlet 140 for each of
the gas delivery conduits 134. Hence, one inlet 140a is in fluid
communication with a first one of the gas delivery conduits 134a, a
second gas inlet 140b is in fluid communication with a second gas
delivery conduit 134b, and a third gas inlet 140c is in fluid
communication with a third gas delivery conduit 134c. In this
design, each of the gas delivery conduits 134 may be adapted to
delivery a process gas flow that is independent of the process gas
flow delivered through each of the other conduits 134. As noted
below, this may permit a different process gas to be delivered
through each of the conduits 134a-c. In the context of the ALD
process outlined above in connection with FIGS. 1 and 2, for
example, one of the gas delivery conduits (e.g., conduit 134a) may
be dedicated to delivering the first precursor gas A, a second one
of the gas delivery conduits (e.g., conduit 134b) may be used to
deliver the second precursor gas B, and the third gas delivery
conduit 134c may be used to deliver the purge gas.
[0043] FIGS. 10-14 schematically illustrate a microfeature
workpiece holder 200 in accordance with another embodiment of the
invention. This microfeature workpiece holder 200 generally
includes a base 210, a cap 250, and at least one column 220
extending between the base 210 and the cap 250. The illustrated
embodiment employs three columns 220a-220c that are spaced
generally equiangularly in a manner similar to that described above
in connection with the microfeature workpiece holder 100 of FIG. 4.
Each of the columns 220a-c may include a series of
longitudinally-spaced slots 222 oriented inwardly toward a central
axis A of the microfeature workpiece holder 200. Each of these
slots 222 may be adapted to receive an edge portion of a
microfeature workpiece W (omitted in FIGS. 10-14 for ease of
understanding). Each of the slots 222 in a particular column 220
may be positioned relative to a corresponding slot 222 in each of
the other columns 220 so the three corresponding slots 222 can
cooperatively support a microfeature workpiece W.
[0044] One of the differences between the microfeature workpiece
holders 100 and 200 of FIGS. 4-8 and 10-14, respectively, relates
to the relationship of the gas distributor to the columns of the
workpiece holder. In the workpiece holder 100 of FIGS. 4-8, the gas
distributor 130 includes several gas delivery conduits 134, each of
which comprises an internal lumen of one of the columns 120. The
microfeature workpiece holder 200 of FIGS. 10-14, in contrast, has
substantially solid columns 220. As suggested in FIGS. 12 and 14,
the columns 220 may have a solid interior with a series of
spaced-apart slots 222 formed in an inwardly-oriented surface of
the column.
[0045] Referring to FIG. 11, the microfeature workpiece holder 200
also includes a gas distributor, generally designated as reference
number 230, that includes a series of gas delivery conduits 234. In
particular, a first gas delivery conduit 234a is carried with
respect to the first column 220a, a second gas delivery conduit
234b is carried with respect to a second column 220b, and a third
gas delivery conduit 234c is carried with respect to a third column
220c. The position of each of the gas delivery conduits 234 may be
fixed relative to the adjacent column 220 in any desired fashion.
In one embodiment, the gas delivery conduits 234 may be supported
entirely by the base 210 and/or the cap 250. In the particular
embodiments shown in FIGS. 10 and 11, a base portion 242 of each of
the conduits 234 is received within and passes through an opening
in the base 210, but the opposite end of the gas delivery conduit
234 is spaced from the cap 250. In another embodiment, each of the
conduits 234 is attached to the cap 250, as well. As shown in FIGS.
11 and 12, each of the gas delivery conduits 234 in the illustrated
embodiment is positioned immediately adjacent to one of the columns
220. In such an arrangement, each of the conduits 234 may be
attached to or otherwise physically supported by the adjacent
column 220. In other embodiments (not shown), the conduits 234 may
be attached only to an adjacent column 220 without being directly
attached to the base 210 or the cap 250. In still other
embodiments, the gas delivery conduits 234 need not be positioned
close to any of the columns 220. For example, one gas delivery
conduit 234 may be positioned between the first two columns 220a
and 220b and a second gas delivery conduit 234 may be positioned
between the second and third columns 220b and 220c.
[0046] The gas delivery conduits 234 provide a fluid pathway
between a gas inlet 240 and a plurality of gas outlets 238. As
illustrated in FIG. 13, the gas delivery conduits 234 (in this
case, gas delivery conduit 234b) may include a longitudinally
extending channel 235 and a series of transverse pathways 236
extending transversely inwardly toward the axis (axis A in FIG. 10)
of the microfeature workpiece holder 200. The outlets 238 of these
pathways 236 may be positioned laterally along the length of the
respective conduit 234 so each outlet 238 can direct a flow of
process gas intermediate a pair of adjacent slots 222. When the
microfeature workpieces W (not shown in FIGS. 10 and 11) are
positioned in the microfeature workpiece holder 200, these outlets
238 would, therefore, direct a flow of process gas into the process
space (S in FIG. 5) defined between two adjacent microfeature
workpieces W.
[0047] The gas distributor 230 of FIGS. 10-14 includes a separate
gas inlet 240 for each of the gas delivery conduits 234. In an
alternative embodiment, two or more of the gas delivery conduits
234 may communicate with a common inlet 240 via a manifold (not
shown) in the base 210, similar to the manifold 132 in the
microfeature workpiece holder 100 discussed above.
C. Microfeature Workpiece Processing Systems
[0048] The microfeature workpiece holders 100, 102, and 200 may be
used for a variety of processes. FIGS. 15-17 schematically
illustrate select microfeature workpiece processing systems that
employ microfeature workpiece holders to process a batch of
microfeature workpieces simultaneously. The microfeature workpiece
holders employed in these processing systems may, in select
embodiments, employ features of the microfeature workpiece holders
100, 102, and/or 200 described above.
[0049] FIG. 15 schematically illustrates a microfeature workpiece
processing system 300 in accordance with one embodiment of the
invention. This system 300 includes a reactor 310 adapted to
receive a plurality of microfeature workpieces W in a holder. In
the specific embodiment shown in FIG. 15, the workpieces W are
carried in a workpiece holder 100 substantially as described above
in connection with FIGS. 4-8.
[0050] The reactor 310 generally includes an enclosure 320 defined
by a wall 322 and a holder-supporting platform 326. The wall 322
may sealingly engage the platform 326, illustrated schematically in
FIG. 15 as an O-ring seal 324. This will define a process chamber
325 within which the microfeature workpiece holder 100 may be
received. The reactor 310 may also include a heater 330 and a
vacuum 340 that communicates with the process chamber 325 by a
vacuum line 342. The heater 330 may be of any conventional design,
e.g., an inductance heater or the like.
[0051] A gas supply system 350 of the reactor 310 generally
includes a plurality of individual gas supplies 352, with at least
one gas supply 352 provided for each of the process gases used in
processing workpieces W in the system 300. The illustrated
embodiment includes a first gas supply 352a to deliver a first gas
(GAS.sub.1), a second gas supply 352b adapted to deliver a second
gas (GAS.sub.2), and a third gas supply 352c adapted to deliver a
third gas (GAS.sub.3). In the context of ALD such as that discussed
above in connection with FIGS. 1 and 2, the first gas supply 352a
may provide a supply of the first precursor A, the second gas
supply 352b may provide a supply of the second precursor B, and the
third gas supply 352c may provide a supply of the purge gas. Each
of the individual gas supplies 352a-c may be provided with an
individual gas supply line 356a-c, respectively. These individual
supply lines 356a-c are coupled to a primary gas supply line 356.
In the illustrated embodiment, each of the individual gas supply
lines 356a-c is provided with a selectively controllable secondary
valve 354a-c, respectively. These secondary valves may be used to
control the flow rate of the gas from each of the individual gas
supply 352 into the main gas supply line 356, hence regulating the
composition and flow rate of gas to the gas supply line 356.
[0052] The gas distributor 130 of the holder 100 may be coupled to
the gas supply system 350 in a variety of manners. In the schematic
illustration of FIG. 15, a gas fitting 360 in the platform 326 may
be releasably coupled to the gas inlet 140 of the holder 100. This
fitting 360 is coupled to the remainder of the gas supply 350 by a
supply line 356.
[0053] The flow of gas through the supply line 356 to the gas
distributor 130 of the holder 100 may be controlled, at least in
part, by a main valve 362 that is under the control of a controller
370. The controller 370 may take any of a variety of forms. In one
embodiment, the controller 30 comprises a computer having a
programmable processor programmed to control operation of the
system 300 to deposit material on the workpieces W. The controller
370 may also be operatively coupled to the secondary valves 354a-c
to control the composition of the gas delivered to the main valve
362 via the supply line 356. The controller 370 may also be coupled
to the vacuum 340 (as illustrated) or any other component of the
processing system 300, e.g., the heater 330.
[0054] FIG. 16 schematically illustrates a microfeature workpiece
processing system 302 in accordance with an alternative embodiment
of the invention. This processing system 302 is similar in many
respects to the processing system 300 of FIG. 15 and like reference
numbers are used in FIGS. 15 and 16 to indicate like elements. The
processing system 300 uses the microfeature workpiece holder 100 of
FIGS. 4-8. The workpieces W in processing system 302 of FIG. 16 are
instead held in the microfeature workpiece holder 102 of FIG. 9. As
noted above, the gas distributor 131 of this holder 102 has a
series of independent gas delivery conduits 134, each of which has
a separate gas inlet 140.
[0055] The gas supply 351 of FIG. 16 is similar in many respects to
the gas supply 350 of FIG. 15. In FIG. 15, each of the individual
gas supply lines 356a-c were joined into a main supply line 356 for
delivery to a single gas fitting 360. In the gas supply 351 of FIG.
16, however, each of the individual gas supplies 352a-c is
independently coupled to a separate gas fitting 360a-c,
respectively. In particular, a first gas fitting 360a may
releasably couple the first gas supply line 356a to the first inlet
140a, a second gas fitting 360b may releasably couple a second gas
supply line 356b to the second gas inlet 140b, and a third gas
fitting 360c may releasably couple a third gas supply line 356c to
the third gas inlet 140c. The flow of gas from each of the gas
supplies 352a-c may be independently controlled by a separate valve
354a-c through a common controller 370. Introducing each of the
process gases through an independent, dedicated gas delivery
conduit 134 can avoid the need to purge the gas delivery conduit
134 after delivering one precursor and before delivering another
precursor. This may be advantageous in CVD applications because it
permits the precursor gases to be introduced separately into the
process chamber 325, more effectively restricting the deposition of
the reactant to the vicinity of the workpieces W.
[0056] FIG. 17 illustrates a microfeature workpiece processing
system 400 in accordance with still another embodiment of the
invention. This processing system 400 generally includes a reactor
410 having a processing enclosure 420 within which a workpiece
holder (e.g., workpiece holder 100 of FIGS. 4-8) carrying one or
more workpieces W may be received. The processing enclosure 420 is
generally defined by an outer wall 422 and a platform 426 adapted
to carry the workpiece holder 100. This processing enclosure 420
also includes a liner 424 that functionally divides the process
chamber 425 into a main chamber 427 and a generally annular exhaust
428 coupled to the vacuum 440 by a vacuum line 442. The reactor 410
may also include a heater 430.
[0057] The processing system 400 may include a first gas supply
system 450 and a second gas supply system 460. The first gas supply
system 450 includes a plurality of individual gas supplies 452a-c,
each of which may include a separate process gas. Hence, the first
gas supply 452a may include a precursor gas A (GAS.sub.1) and a
second gas supply 452b may provide a supply of a second precursor
gas B (GAS.sub.2). Optionally, the first gas supply system 450 may
also include a supply of a purge gas (GAS.sub.3) in a third gas
supply. Each of these individual gas supplies 452a-c may be coupled
to a common gas supply line 456. A separate valve 454a, 454b, or
454c may be operated by a controller 470 to control the flow of gas
from the individual gas supplies 452a, 452b, and 452c,
respectively.
[0058] The gas supply line 456 of the first gas supply system 450
may be in fluid communication with one or more gas supply nozzles
458. The gas supply nozzle 458 may be adapted to deliver a flow of
process gas to the main chamber 427 outside the process spaces S of
the process chamber 425. This gas may flow generally longitudinally
through the main chamber 427 then out of the process chamber 425
via the annular exhaust 428. This gas supply system 450 is, in some
respects, analogous to the gas supply 30 and gas nozzle 32
illustrated in FIG. 3.
[0059] The microfeature workpiece processing system 400 also
includes a second gas supply system 460. This gas supply system 460
may be adapted to deliver one or more process gases to the process
chamber 425 via the gas distributor 130 of the workpiece holder
100. Gas will exit the outlets 138 of the gas distributor 130 in a
direction transverse to the longitudinally directed flow from the
nozzle 458. In the specific embodiment shown in FIG. 17, the second
gas supply system 460 includes a single individual gas supply 462
containing a purge gas (GAS.sub.3). The individual gas supply 462
is coupled to a gas fitting 468 in the platform 426 by a valve 464
operatively linked to the controller 470. The gas fitting 468 is
adapted to be releasably coupled to the inlet 140 of the gas
distributor 130. Although the second gas supply system 460 shown in
FIG. 16 only provides a supply of a single purge gas, this gas
supply system 460 may include two or more individual gas supplies
462 to provide a variety of different process gas compositions to
the gas distributor 130.
D. Methods of Depositing Materials On Microfeature Workpieces
[0060] 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 systems 300, 302, and 400 shown in FIGS.
15-17. It should be understood, though, that reference to these
particular processing systems and the workpiece holders used
therein is solely for purposes of illustration and that the methods
outlined below are not limited to any particular workpiece holder
or processing system shown in the drawings or discussed in detail
above. In addition, the following discussion focuses primarily on
ALD and also touches on possible CVD applications. It should be
recognized that the processes outlined below should not be limited
to these specific deposition processes. Indeed, aspects of the
methods outlined below may have utility in applications in which a
process other than material deposition, e.g., selective etching,
may be carried out.
[0061] In accordance with one embodiment, a method of processing
microfeature workpieces may include positioning a microfeature
workpiece holder 100 in a process chamber 325 (using the processing
system 300 as an example). The workpiece holder 100 may support a
plurality of workpieces W in a spaced-apart relationship to define
a process space S between each pair of adjacent workpieces W. The
microfeature workpiece holder 100 may be positioned in the process
chamber by placing the holder 100 on a platform 326. In one
embodiment, the gas fitting 360 may be coupled to the gas inlet 140
of the gas distributor 130 at this time. Once the holder 100 is in
place on the platform 326, the platform 326 may be moved toward the
wall 322 until the seals 324 substantially seal the enclosure 320
to define the process chamber 325.
[0062] This embodiment also includes delivering at least a first
process gas and a second process gas to the process chamber 325. In
one embodiment, the first process gas, e.g., a first precursor A,
may be delivered to the process chamber 325 by opening the first
regulator valve 354a and the main valve 362. This will allow the
first gas to flow into the gas distributor 130 and outwardly into
the process chamber 325 via the outlets 138. As noted above, these
outlets 138 will deliver a flow of the process gas transversely
into the process spaces S between the workpieces W.
[0063] The second process gas may be delivered to the process
chamber 325 either simultaneously with delivery of the first
process gas (e.g., for CVD) or at a different time. If the
processing system 300 of FIG. 15 is used to deposit a material via
ALD, for example, a flow of the first precursor gas A from the
first supply 352a may be terminated by closing the valve 354a. A
flow of purge gas from the third gas supply 352c may be delivered
into the process spaces S by opening the associated regulator valve
154c. The regulator valve 154c may be closed and a flow of the
second precursor gas B from the second gas supply 352b may then be
introduced via the nozzles 138. By appropriate control of the
valves 354 and 362 and the vacuum 340, the controller 370 may be
used to deposit a reaction product via an ALD process such as that
discussed above in connection with FIGS. 1 and 2.
[0064] Delivering process gases transversely into the process space
S between the workpieces W via the outlets 138 can fairly rapidly
change the gas present in the process space S. In the conventional
system of FIG. 3, one of the primary mechanisms for gas exchange in
the spaces between the workpieces W is diffusion. Delivering a
transverse flow of gas in accordance with embodiments of the
present invention can deliver a more uniform application of the
precursors to be chemisorbed or reacted on the surface of the
workpiece W. Delivering the purge gas through the outlets 138 will
also provide a more active scrubbing of the gas in the process
spaces S, helping clear the process spaces S of any excess
precursor gas fairly quickly. This can materially speed up the
purge phases of the process illustrated in FIG. 2.
[0065] The processing system 300 of FIG. 15 introduces process
gases through a single inlet 140 and the gas distributor 130 of the
workpiece holder 100. The processing system 302 of FIG. 16 allows
each of the process gases (gas.sub.1-3) to be introduced into the
process chamber 325 through a separate gas delivery conduit 134a,
134b, or 134c. This can be particularly useful in both ALD and CVD
applications. By separating the pathways for delivery of the
reaction precursors into separate conduits 134, less care need be
taken to purge the gas delivery system of the first precursor
before introducing a second precursor through the same gas delivery
system. In the context of CVD, the gas can be introduced separately
and allowed to mix in the process space S and react in the
immediate vicinity of the workpiece W. This may facilitate use of
more highly reactive precursors, which may be problematic if the
precursors are introduced together through a common gas delivery
path.
[0066] In another specific embodiment, one of the process gases may
be introduced through the gas distributor 130 of the workpiece
holder 100, but the second process gas may be delivered through a
delivery conduit independent of the gas distributor 130. In the
context of the microfeature workpiece processing system 400 of FIG.
17, for example, the precursor gases may be introduced from
separate individual gas supplies 452a and 452b through the gas
delivery nozzle 458. This will deliver the precursors to the
process spaces S between the workpieces W in a fashion analogous to
that in the ALD reactor 10 of FIG. 3. In the purge stages
illustrated in FIG. 2, though, the purge gas (gas.sub.3) may be
introduced through the gas distributor 130 either in addition to or
instead of introducing the purge gas through the nozzle 458.
Delivering the purge gas through the outlets 138 of the workpiece
holder gas distributor 130 will help positively scrub the
processing spaces S, fairly rapidly sweeping away any excess
precursor.
[0067] 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.
[0068] 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.
[0069] 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.
* * * * *