U.S. patent application number 13/721323 was filed with the patent office on 2014-03-06 for gas injector for high volume, low cost system for epitaxial silicon depositon.
This patent application is currently assigned to APPLIED MATERIALS, INC.. The applicant listed for this patent is APPLIED MATERIALS, INC.. Invention is credited to DAVID K. CARLSON, KASHIF MAQSOOD, PRAVIN K. NARWANKAR, MICHAEL R. RICE, KARTIK B. SHAH.
Application Number | 20140060434 13/721323 |
Document ID | / |
Family ID | 50185658 |
Filed Date | 2014-03-06 |
United States Patent
Application |
20140060434 |
Kind Code |
A1 |
CARLSON; DAVID K. ; et
al. |
March 6, 2014 |
GAS INJECTOR FOR HIGH VOLUME, LOW COST SYSTEM FOR EPITAXIAL SILICON
DEPOSITON
Abstract
Apparatus for use in a substrate processing chamber are provided
herein. In some embodiments, a gas injector for use in a process
chamber may include first set of gas orifices configured to provide
a jet flow of a first process gas into the process chamber, and a
second set of gas orifices configured to provide a laminar flow of
a second process gas into the process chamber, wherein the first
set of gas orifices are disposed between at least two gas orifices
of the second set of gas orifices.
Inventors: |
CARLSON; DAVID K.; (San
Jose, CA) ; RICE; MICHAEL R.; (Pleasanton, CA)
; SHAH; KARTIK B.; (Sunnyvale, CA) ; MAQSOOD;
KASHIF; (San Francisco, CA) ; NARWANKAR; PRAVIN
K.; (Sunnyvale, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
APPLIED MATERIALS, INC. |
Santa Clara |
CA |
US |
|
|
Assignee: |
APPLIED MATERIALS, INC.
Santa Clara
CA
|
Family ID: |
50185658 |
Appl. No.: |
13/721323 |
Filed: |
December 20, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61696778 |
Sep 4, 2012 |
|
|
|
61711493 |
Oct 9, 2012 |
|
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Current U.S.
Class: |
118/728 ;
239/296 |
Current CPC
Class: |
H01L 21/67017 20130101;
C30B 25/08 20130101; H01L 21/67028 20130101; H01L 21/67712
20130101; H01L 21/67115 20130101; H01L 21/683 20130101; C30B 25/14
20130101; B05B 1/005 20130101; H01L 21/67173 20130101; E05F 1/00
20130101; H01L 21/6776 20130101; C30B 29/06 20130101 |
Class at
Publication: |
118/728 ;
239/296 |
International
Class: |
C30B 25/14 20060101
C30B025/14; B05B 1/00 20060101 B05B001/00 |
Claims
1. A gas injector for use in a process chamber, comprising: a first
set of gas orifices configured to provide a jet flow of a first
process gas into the process chamber; and a second set of gas
orifices configured to provide a laminar flow of a second process
gas into the process chamber, wherein the first set of gas orifices
are disposed between at least two gas orifices of the second set of
gas orifices.
2. The gas injector of claim 1, wherein the gas injector includes
an elongated body, and wherein the first set and the second set of
gas orifices are disposed on a first surface of the elongated
body.
3. The gas injector of claim 2, wherein the elongated body
comprises an injector plate coupled to a base plate, and wherein
the first and second set of gas orifices are disposed in the
injector plate.
4. The gas injector of claim 3, wherein the base plate includes a
plurality of plenums configured to receive process gases via
respective inlets.
5. The gas injector of claim 4, wherein the first and second sets
of gas orifices are separated into zones, each zone associated with
one of the plurality of plenums.
6. The gas injector of claim 5, further comprising: a flow
controller coupled to each zone such that gas injection via each of
the zones can be modulated at least one of temporally or spatially
by starting, stopping, or varying the flow rates of the first and
second process gases.
7. The gas injector of claim 1, further comprising a first gas
supply coupled to the first and second set of gas orifices such
that the first and second process gases are a same species of
gases.
8. The gas injector of claim 1, further comprising: a first gas
supply coupled to the first set of gas orifices; and a second gas
supply coupled to the second set of gas orifices, such that the
first and second process gases are different species of gases.
9. The gas injector of claim 1, further comprising a third set of
gas orifices surrounding the first and second set of gas orifices,
the third set of gas orifices configured to provide a purge gas
barrier into the process chamber.
10. The gas injector of claim 1, wherein the gas injector is
fabricated from transparent quartz (SiO.sub.2).
11. The gas injector of claim 1, wherein the gas injector is
fabricated from a non-transparent quartz (SiO.sub.2).
12. A substrate processing tool, comprising: a substrate carrier
having a base and pair of opposing substrate supports having
respective substrate support surfaces that extend upwardly from the
base and configured to support one or more substrates when disposed
thereon; and a first substrate processing module including an
enclosure having a lower surface to support the substrate carrier,
wherein the substrate processing module comprises: a gas injector
including a first set of gas orifices configured to provide a jet
flow of a first process gas towards a central area between the pair
of opposing substrate supports, and a second set of gas orifices
disposed on both sides of the first set of gas orifices and
configured to provide a laminar flow of a second process gas over
substrates when disposed on the substrate carriers; and an exhaust
disposed opposite the gas injector to remove the first and second
process gases from the enclosure.
13. The substrate processing tool of claim 12, wherein the
substrate processing tool is an indexed inline substrate processing
tool that includes a plurality of substrate processing modules
coupled to one another in a linear arrangement, wherein each
substrate processing module of the plurality of substrate
processing modules comprises an enclosure having a first end, a
second end, and a lower surface to support the substrate carrier
and to provide a path for the substrate carrier to move linearly
through the plurality of modules from a first module of the
plurality of modules, through any intervening modules, to a last
module of the plurality of modules.
14. The substrate processing tool of claim 13, wherein the gas
injector further comprises a third set of gas orifices configured
to provide a purge gas barrier around the substrate carrier
proximate walls of the first substrate processing module, wherein
the purge gas barrier substantially prevents cross-contamination or
deposition between the plurality of substrate processing
modules.
15. The substrate processing tool of claim 12, wherein the gas
injector includes an elongated body, and wherein the first set and
the second set of gas orifices are disposed on a first surface of
the elongated body.
16. The substrate processing tool of claim 15, wherein the
elongated body comprises an injector plate coupled to a base plate,
and wherein the first and second set of gas orifices are disposed
in the injector plate.
17. The substrate processing tool of claim 16, wherein the base
plate includes a plurality of plenums configured to receive process
gases via respective inlets.
18. The substrate processing tool of claim 17, wherein the first
and second sets of gas orifices are separated into zones, each zone
associated with one of the plurality of plenums.
19. The substrate processing tool of claim 18, further comprising:
a flow controller coupled to each zone such that gas injection via
each of the zones can be modulated at least one of temporally or
spatially by starting, stopping, or varying the flow rates of the
first and second process gases.
20. The substrate processing tool of claim 12, further comprising a
third set of gas orifices surrounding the first and second set of
gas orifices, the third set of gas orifices configured to provide a
purge gas barrier into the process chamber proximate one or more
vertical walls of the process chamber.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of U.S. provisional patent
application Ser. No. 61/696,778, filed Sep. 4, 2012, and of U.S.
provisional patent application Ser. No. 61/711,493, filed Oct. 9,
2012, both of which are herein incorporated by reference in their
entirety.
FIELD
[0002] Embodiments of the present invention generally relate to
semiconductor processing equipment, and more specifically, to gas
injectors for use in equipment and techniques for solar cell
manufacturing, such as high efficiency single crystal epitaxial
film deposition equipment.
BACKGROUND
[0003] Amorphous and polycrystalline solar cells are limited in
their efficiency to convert light into energy. Single crystal high
mobility materials are capable of much higher efficiency, but are
typically much more expensive. Conventional equipment is designed
for semiconductor applications with extreme requirements and with a
very high cost involved. However, these systems all have high cost
and are not capable of high throughput automation.
[0004] To achieve very low cost epitaxial deposition for
photovoltaic applications at high throughput, the inventors believe
that a radical change is required rather than simply making
everything larger. For example, the inventors have observed that
batch reactors are limited in throughput with high cost of
materials, consumables, and automation challenges. Very high flow
rates of hydrogen, nitrogen, water, and precursors are also
required. Furthermore, a large amount of hazardous byproducts are
generated when growing thick films.
[0005] Continuous reactors have been attempted many times for
epitaxial processes but have never been production worthy nor
achieved good precursor usage. The major issue is poor film quality
and excessive maintenance.
[0006] On the other hand, single wafer reactors have very
inefficient utilization of precursors and power (electrical) and
have lower per wafer throughput. Plus single wafer reactors need
complex substrate lift/rotation mechanisms. Thus, although single
wafer reactors can have very high quality, low metal contamination
levels, and good thickness uniformity and resistivity, the cost per
wafer is very high to get these results.
[0007] Therefore, the inventors have provided embodiments of a
substrate processing tool that may provide some or all of high
precursor utilization, simple automation, low cost, and a
relatively simple reactor design having high throughput and process
quality.
SUMMARY
[0008] Apparatus for use in a substrate processing chamber are
provided herein. In some embodiments, a gas injector for use in a
process chamber may include first set of gas orifices configured to
provide a jet flow of a first process gas into the process chamber,
and a second set of gas orifices configured to provide a laminar
flow of a second process gas into the process chamber, wherein the
first set of gas orifices are disposed between at least two gas
orifices of the second set of gas orifices.
[0009] In some embodiments, a substrate processing tool may include
a substrate carrier having a base and pair of opposing substrate
supports having respective substrate support surfaces that extend
upwardly from the base and configured to support one or more
substrates when disposed thereon, and a first substrate processing
module including an enclosure having a lower surface to support the
substrate carrier, wherein the substrate processing module includes
a gas injector including a first set of gas orifices configured to
provide a jet flow of a first process gas towards a central area
between the pair of opposing substrate supports, and a second set
of gas orifices disposed on both sides of the first set of gas
orifices and configured to provide a laminar flow of a second
process gas over substrates when disposed on the substrate
carriers, and an exhaust disposed opposite the gas injector to
remove the first and second process gases from the enclosure.
[0010] Other and further embodiments of the present invention are
described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Embodiments of the present invention, briefly summarized
above and discussed in greater detail below, can be understood by
reference to the illustrative embodiments of the invention depicted
in the appended drawings. It is to be noted, however, that the
appended drawings illustrate only typical embodiments of this
invention and are therefore not to be considered limiting of its
scope, for the invention may admit to other equally effective
embodiments.
[0012] FIG. 1 depicts an indexed inline substrate processing tool
in accordance with some embodiments of the present invention.
[0013] FIG. 2 is a cross sectional view of a module of a substrate
processing tool in accordance with some embodiments of the present
invention.
[0014] FIG. 3 is a module of a substrate processing tool in
accordance with some embodiments of the present invention.
[0015] FIG. 4A is a schematic top view of a gas inlet in accordance
with some embodiments of the present invention.
[0016] FIGS. 4B and 4C respectively depict an isometric view and an
exploded isometric view of another gas inlet in accordance with
some embodiments of the present invention.
[0017] FIGS. 4D is a schematic cross-section side of a gas inlet
disposed in a substrate processing module in accordance with some
embodiments of the present invention.
[0018] FIG. 4E is a schematic control block diagram of a gas inlet
disposed in a substrate processing module in accordance with some
embodiments of the present invention.
[0019] FIG. 5 is a substrate carrier for use in a substrate
processing tool in accordance with some embodiments of the present
invention.
[0020] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures. The figures are not drawn to scale
and may be simplified for clarity. It is contemplated that elements
and features of one embodiment may be beneficially incorporated in
other embodiments without further recitation.
DETAILED DESCRIPTION
[0021] Embodiments of a high volume, low cost system for epitaxial
silicon deposition are provided herein. While not limiting in
scope, the inventors believe that the inventive substrate
processing system may be particularly advantageous for solar cell
fabrication applications.
[0022] The inventive system may advantageously provide cost
effective and simple manufacturability and an energy and cost
efficient usage, as compared to conventional substrate processing
tools utilized to perform multi-step substrate processes.
[0023] For example, basic design components are based on flat
plates to simplify manufacturing and contain cost by using readily
available materials in standard forms to keep cost down. High
reliability linear lamps can be used. The specific lamps can be
optimized for the specific application. The lamps may be of the
type typically used in epitaxial deposition reactors. Flow fields
within the system can also be optimized for each specific
application to minimize waste. The design minimizes purge gas
requirements and maximizes precursor utilization. Cleaning gas may
be added to an exhaust system to facilitate removal of deposited
material from the exhaust channels. Load and unload automation can
also be separated to facilitate inline processing. Complex
automation can be handled offline. Substrates are pre-loaded on
carriers (susceptors) for maximum system flexibility, thereby
facilitating integration to other steps. The system provides for
flexibility of the system configuration. For example, multiple
deposition chambers (or stations) can be incorporated for
multilayer structures or higher throughput.
[0024] Embodiments of a high volume, low cost system for epitaxial
silicon deposition may be performed using a standalone substrate
processing tool, a cluster substrate processing tool or an indexed
inline substrate processing tool cluster substrate processing tool
or an indexed inline substrate processing tool. FIG. 1 is an
indexed inline substrate processing tool 100 in accordance with
some embodiments of the present invention. The indexed inline
substrate processing tool 100 may generally be configured to
perform any process on a substrate for a desired semiconductor
application. For example, in some embodiments, the indexed inline
substrate processing tool 100 may be configured to perform one or
more deposition processes, for example, such as an epitaxial
deposition process.
[0025] The indexed inline substrate processing tool 100 generally
comprises a plurality of modules 112 (first module 102A, second
module 102B, third module 102C, fourth module 102D, fifth module
102E, six module 102F, and seventh module 102G shown) coupled
together in a linear arrangement. A substrate may move through the
indexed inline substrate processing tool 100 as indicated by the
arrow 122. In some embodiments, one or more substrates may be
disposed on a substrate carrier, for example, such as the substrate
carrier 502 described below with respect to FIG. 5 to facilitate
movement of the one or more substrates through the indexed inline
substrate processing tool 100.
[0026] Each of the plurality of modules 112 may be individually
configured to perform a portion of a desired process. By utilizing
each of the modules to perform only a portion of a desired process,
each module of the plurality of modules 112 may be specifically
configured and/or optimized to operate in a most efficient manner
with respect to that portion of the process, thereby making the
indexed inline substrate processing tool 100 more efficient as
compared to conventionally used tools utilized to perform
multi-step processes.
[0027] In addition, by performing a portion of a desired process in
each module, process resources (e.g., electrical power, process
gases, or the like) provided to each module may be determined by
the amount of the process resource required only to complete the
portion of the process that the module is configured to complete,
thereby further making the inventive indexed inline substrate
processing tool 100 more efficient as compared to conventionally
used tools utilized to perform multi-step processes.
[0028] Furthermore, separate modules advantageously allow for
depositing layers of differing dopants on one or more substrates:
for example, 10 microns of p++ dopants; 10 microns of p+ dopants;
10 microns of n dopants. Meanwhile, conventional single chambers
prohibit deposition of different dopants since they interfere with
each other. In addition, inline linear deposition where an
epitaxial layer is built up in separate chambers helps to prevent
over growth or bridging of the epitaxial Silicon (Si) from the
substrate over the carrier due to use of a purge gas between
modules (discussed below), providing an etch effect during the
transfer stage from one module to the next.
[0029] In an exemplary configuration of the indexed inline
substrate processing tool 100, in some embodiments, the first
module 102A may be configured to provide a purge gas to, for
example, remove impurities from the substrate and/or substrate
carrier and/or introduce the substrate into a suitable atmosphere
for deposition. The second 102B module may be configured to preheat
or perform a temperature ramp to raise a temperature of the
substrate to a temperature suitable for performing the deposition.
The third module 102C may be configured to perform a bake to remove
volatile impurities from the substrate prior to the deposition of
the materials. The fourth module 102D may be configured to deposit
a desired material on the substrate. The fifth module 102E may be
configured to perform a post-deposition process, for example such
as an annealing process. The sixth module 102F may be configured to
cool the substrate. The seventh module 102G may be configured to
provide a purge gas to, for example, remove process residues from
the substrate and/or substrate carrier prior to removal from the
indexed inline substrate processing tool 100. In embodiments where
certain processes are not needed, the module configured for that
portion of the process may be omitted. For example, if no anneal is
needed after deposition, the module configured for annealing (e.g.,
the fifth module 102E in the exemplary embodiment above) may be may
be omitted or may be replaced with a module configured for a
different desired process.
[0030] Some embodiments of substrate processing tool 100 include an
inline "pushing mechanism" (now shown) or other mechanism that is
able to serially transfer the abutting substrate carriers through
modules 102A-102G. For example, indexed transport can use a
pneumatic plunger-type push mechanism to drive carrier modules
forward through the in-line reactor.
[0031] Some or all of the plurality of modules may be isolated or
shielded from adjacent modules, for example by a barrier 118, to
facilitate maintaining an isolated processing volume with respect
to other modules in the indexed inline substrate processing tool
100. For example, in some embodiments, the barrier 118 may be a gas
curtain, such as of air or of an inert gas, provided between
adjacent modules to isolate or substantially isolate the modules
from each other. In some embodiments, gas curtains can be provided
along all four vertical walls of each module, or of desired modules
(such as deposition or doping modules), to limit unwanted
cross-contamination or deposition in undesired locations of the
module or carriers. Such isolation also prevents contaminants such
as carbon or moisture from reaching the reaction
zone/substrates.
[0032] In some embodiments, the barrier 118 may be a gate or door
may that can open to allow the substrate carrier to move from one
module to the next, and can be closed to isolate the module. In
some embodiments, the indexed inline substrate processing tool 100
may include both gas curtains and gates, for example, using gas
curtains to separate some modules and gates to separate other
modules, and/or using gas curtains and gates to separate some
modules. Once the push mechanism delivers the substrate carriers to
a desired position in each chamber, a door/gate assembly (and
chamber liner elements) forms a seal around the substrate carrier
to form an enclosed region within each chamber. As the door
mechanism is opening or closing a gas flow (i.e., gas purge, or gas
curtain) is provided between each door and its adjacent carriers to
prevent cross-contamination between chambers. The provided gas flow
is received by one or more exhaust ports that are disposed in the
bottom of the processing tool 100.
[0033] In some embodiments, isolation is provided by purge gas
curtains using nitrogen or argon gas depending on the location of
the gas curtain. For example, the gas curtain in the hotter
processing regions would be formed using argon gas. The gas
curtains in colder regions near the gates, away from the hotter
processing regions, could by nitrogen to minimize cost of
operation. The nitrogen gas curtains can only be used in cold,
inert sections of each module.
[0034] In some embodiments, a load module 104 may be disposed at a
first end 114 of the indexed inline substrate processing tool 100
and an unload module 106 may be disposed at a second end 116 of the
indexed inline substrate processing tool 100. When present, the
load module 104 and unload module 106 may facilitate providing a
substrate to, and removing a substrate from, the indexed inline
substrate processing tool 100, respectively. In some embodiments,
the load module 104 and the unload module 106 may provide vacuum
pump down and back to atmospheric pressure functions to facilitate
transfer of substrates from atmospheric conditions outside of the
indexed inline substrate processing tool 100 to conditions within
the indexed inline substrate processing tool 100 (which may include
vacuum pressures). In some embodiments, one or more substrate
carrier transfer robots may be utilized to provide and remove the
substrate carrier from the load module 104 and the unload module
106, thereby providing an automated loading and unloading of the
substrate carrier to and from the indexed inline substrate
processing tool 100.
[0035] In some embodiments, a track 120 may be provided along the
axial length of the indexed inline substrate processing tool 100 to
facilitate guiding the substrate carrier through the indexed inline
substrate processing tool 100. The track 120 may be provided along
a floor of a facility or other base surface upon which the indexed
inline substrate processing tool 100 is mounted. In such
embodiments, each module may be configured to be assembled such
that the track 120 may be positioned along an exposed bottom
portion of the module to facilitate moving the substrate carrier
along the track 120 and through each respective module.
Alternatively, the track 120 may be mounted to a bottom surface of
the modules once assembly in a linear array. Alternatively,
portions of the track 120 may be mounted to a bottom surface of
each individual module such that the complete track 120 is formed
after assembly of all of the modules in a linear array. In some
embodiments, the track 120 may include wheels, ball bearings or
other types of rollers to facilitate low friction movement of the
substrate carrier along the track 120. In some embodiments, the
track 120 may be fabricated from or may be coated with a low
friction material, such as described below with respect to FIG. 2,
to facilitate low friction movement of the substrate carrier along
the track 120.
[0036] In some embodiments, a cleaning module 110 may be disposed
between the load module 100 and the unload module 106. When
present, the cleaning module 110 may clean and/or prepare the
substrate carrier to receive another one or more substrates for a
subsequent run through the indexed inline substrate processing tool
100 (as indicated by the return path arrow 108). As such, the
substrate carriers may be re-used multiple times.
[0037] FIG. 2 depicts a cross sectional view of an exemplary
configuration of a module, such as module 102D, that may be used as
one or more of the modules of the plurality of modules 112
described above, and in some embodiments, as a module configured
for the deposition of materials on a substrate. Although generally
discussed below in terms of a specific module (102E), the below
discussion generally applies to all modules with the exception of
components and/or configurations only specifically required for a
deposition process.
[0038] Referring to FIG. 2, in some embodiments, the module 102D
generally comprises an enclosure 202. The enclosure 202 may be
fabricated from any material suitable for semiconductor processing,
for example, a metal such as aluminum, stainless steel, or the
like. The enclosure 202 may have any dimensions suitable to
accommodate a substrate carrier (e.g., substrate carrier 502
described below) configured to carry one or more substrates of a
given size as well as to facilitate a desired flow rate and
profile. For example in some embodiments, the enclosure may have a
height and length of about 24 inches or about 36 inches and a depth
of about 6 inches.
[0039] In some embodiments, the enclosure 202 may be assembled by
coupling a plurality of plates together to form the enclosure 202.
Each enclosure 202 may be configured to form a particular module
(e.g., module 102D) that is capable of performing a desired portion
of a process. By assembling the enclosure 202 in such a manner, the
enclosure 202 may be produced in multiple quantities for multiple
applications via a simple and cost effective process.
[0040] A lower surface 206 of the enclosure supports the substrate
carrier and provides a path for the substrate carrier to move
linearly through the module 102D to an adjacent module of the
plurality of modules. In some embodiments, the lower surface 206
may be configured as the track 120. In some embodiments, the lower
surface 206 may have the track 120, or a portion thereof, coupled
to the lower surface 206. In some embodiments, the lower surface
206, or the track 120, may comprise a coating, for example, a dry
lubricant such as a nickel alloy (NiAl) containing coating, to
facilitate movement of the substrate carrier through the module
102D. Alternatively, or in combination, in some embodiments, a
plurality of rollers (shown in phantom at 228) may be disposed
above the lower surface 206 to facilitate movement of the substrate
carrier through the module 102D. In such embodiments, the plurality
of rollers 228 may be fabricated from any material that is
non-reactive to the process environment, for example, such as
quartz (SiO.sub.2).
[0041] In some embodiments, a barrier 219 may be disposed proximate
the first end 216 and/or second end 218 of the enclosure 202 (e.g.,
to form the barrier 118 as shown in FIG. 1). When present, the
barrier 219 isolates each module of the plurality of modules from
an adjacent module to prevent cross contamination or mixing of
environments between modules. In some embodiments, the barrier 219
may be a stream of gas, for example a purge gas, provided by a gas
inlet (e.g., such as the gas inlet 208) disposed above the module
102D. Alternatively, or in combination, in some embodiments, the
barrier 219 may be a movable gate. The gate provides additional
isolation for certain processes, for example, during the deposition
part of the sequence.
[0042] In some embodiments, the gate may be fabricated from a
metal, such as aluminum, polished stainless steel, or the like. In
other embodiments, the gates in hotter regions of the processing
system can be made out of quartz to withstand the high
temperatures.
[0043] In some embodiments, the module 102D may comprise one or
more windows disposed in one or more sides of the enclosure, for
example such, as the window 214 disposed in the side 220 of the
enclosure 202, as shown in FIG. 2. When present, the window 214
allows radiant heat to be provided into the enclosure 202 from, for
example, a radiant heat lamp disposed on a side of the window 214
opposite the interior of the enclosure 202. The window 214 may be
fabricated from any material suitable to allow the passage of
radiant heat through the window 214 while resisting degradation
when exposed to the processing environment within the enclosure
202. For example, in some embodiments, the window 214 may be
fabricated from quartz (SiO.sub.2).
[0044] In some embodiments, the module 102D may include a gas inlet
208 disposed proximate a top 230 of the enclosure 202 to provide
one or more gases into the enclosure 202 via through holes 231
formed in the enclosure 202. The gas inlet 208 may be configured in
any manner suitable to provide a desired process gas flow to the
enclosure 202. Gas injection may be provided between the two
substrate carriers to contain the process gases in the reaction
zone between the two substrate carriers, and/or purge gases between
the substrate carriers and the module walls.
[0045] For example, referring to FIG. 4A, in some embodiments, the
gas inlet 208 may comprise a gas distribution plate 402 having a
plurality of gas orifices 410. The gas orifices 410 may be
configured to provide a desired flow of process gases into the
enclosure 202. For example, in some embodiments, the gas orifices
410 may comprise a plurality of inner gas holes 408 and a plurality
of outer gas slots 406, such as shown in FIG. 4A. In such
embodiments, the inner gas holes 408 may provide a high velocity
jet flow of process gases to a central area of the enclosure 202 to
facilitate a process. In some embodiments, outer gas slots 406 may
provide a lower velocity laminar flow of process gases over
substrates disposed in the substrate carriers.
[0046] In addition, outer gas slots 406 may be disposed on either
side of the inner gas holes 408, closer to the walls of the module
but still within the reaction zone, and to account for the angle of
the substrate supports (e.g., outer gas slots 406 may be disposed
closer to the walls for substrate support disposed at about a
6.degree. angle then for a substrate support disposed at about a
3.degree. angle). In some embodiments, the outer gas slots 406
inject process gases perpendicular to the injector. In other
embodiments, the outer gas slots 406 may be configured or adjusted
to flow process gases parallel to the substrate support surfaces
(e.g., the outer gas slots 406 may be angled to provide laminar
flow across the surface of the substrates at the same angle that
the substrate support carrier supports the substrates.
[0047] Referring to FIGS. 4B and 4C, in some embodiments, the gas
distribution plate 402 of gas inlet 208 may comprise an injector
plate 420 coupled to base plate 422. Injector plate 420 may be
coupled to base plate 422 via fasteners using fastener holes 424,
or may be bonded together in a manner suitable to withstand the
environmental conditions produced during substrate processing. In
some embodiments, base plate 422 may include a plurality of plenums
426 (as depicted in FIG. 4C). Each plenum 426 may receive one or
more process gases via one or more inlets 428 disposed in each
plenum 426.
[0048] As shown in FIG. 4C, separate zones of inner gas holes 408
and outer gas slots 406 may be associated with each plenum 426, and
gas injection via each of the zones may be modulated accordingly.
For example, in FIG. 4C, zone 430 on injector plate 420 includes
outer gas slots 406 that correspond with plenum zone 430'. In some
embodiments, gas injection via the different zones of inner gas
holes 408 and outer gas slots 406 may be modulated temporally
and/or spatially by starting, stopping, and/or varying the flow
rates of the gases over time and/or from one plenum 426 to another
(for example, from one end to the other of the module). Gas
injection via inner gas holes 408 and outer gas slots 406 may also
be modulated by dynamically adjusting through the use of fine
tuning (for example flow controllers or valves as shown in FIG. 4E
and described below) which are able to control flow rates and/or
which holes 408 or slots 406 (or zones of holes 408 or slots 406)
are used. That is, some embodiments of gas inlet 208 include a gas
distribution plate 402 that has a plurality of zones that are able
to dynamically adjust the spatial (e.g., row-by-row,
column-by-column or by region of the carrier) and/or temporal
delivery of the gases to the substrates. This may, for example,
assure that the substrates that are farthest from gas distribution
plate 402 in the processing chamber will include deposited layers
that have similar physical, electrical, and structural properties
as layers deposited on substrates that are disposed closer to the
gas distribution plate 402.
[0049] The gas distribution plate 402, including injector plate 420
and base plate 422, may be fabricated from any suitable material,
for example, such as transparent or non-transparent quartz
(SiO.sub.2). The heat transfer coefficient of the material used for
the gas distribution plate 402, or the transparency of the quartz
used, may be selected to control heating of the gas inlet 208 by
the lamps and to prevent or limit undesired deposition of material
onto the gas inlet 208 during substrate processing.
[0050] FIG. 4D depicts a side view of gas inlet 208 disposed in
module 102D. As shown in FIG. 4D, gas inlet 208 may include another
set of purge gas slots 432 to provide a purge curtain as barrier
118 (or in combination with a gate, when gates or doors are used as
the barrier), as discussed above with respect to FIG. 1. The purge
curtain can be provided along all four vertical walls of each
module by the purge gas slots, or of desired modules (such as
deposition or doping modules), to limit unwanted
cross-contamination or deposition in undesired locations of the
module or carriers. That is, the purge gas slots 432 may provide
flow of purge gas to one or more cold zones within the enclosure
(e.g., proximate the windows 214 and/or gates or doors, as
described above) to reduce or eliminate unwanted deposition of
materials within the cold zones.
[0051] Referring to FIG. 4E, as discussed above, some embodiments
of gas inlet 208 include a gas distribution plate 402 that has a
plurality of zones that are able to dynamically adjust the spatial
(e.g., row-by-row, column-by-column or by region of the carrier)
and/or temporal delivery of the gases to the substrates. In some
embodiments, each of the inlets 428 that supply process gases to
each of the plenums 426 may be coupled a mass flow controller 440
(via a gas supply conduit 448). The flow controllers may include
valves, mass flow, controllers, and the like. The flow controllers
440 may be coupled gas supplies 442. In some embodiments, gas
supplies 442 may be the same gas species or different gas species.
Although not shown, in some embodiments, purge gas slots 432 may
also coupled to one or more flow controllers 440 and gas supplies
442. The flow controllers 440 and gas supplies 442 may be
operatively coupled to a controller 450 to control the amount,
timing and concentration of the one or more process gases supplied.
The controller 450 includes a central processing unit (CPU) 452, a
memory 454, and support circuits 456. The controller 450 may be one
of any form of general-purpose computer processor that can be used
in an industrial setting for controlling various substrate
processing tools or components thereof. The memory, or computer
readable medium, 454 of the controller 450 may be one or more of
readily available memory such as random access memory (RAM), read
only memory (ROM), floppy disk, hard disk, optical storage media
(e.g., compact disc or digital video disc), flash drive, or any
other form of digital storage, local or remote. The support
circuits 456 are coupled to the CPU 452 for supporting the
processor in a conventional manner. These circuits include cache,
power supplies, clock circuits, input/output circuitry and
subsystems, and the like. Inventive methods as described herein may
be stored in the memory 454 as software routine that may be
executed or invoked to control the operation of the gas inlet 208
in the manner described herein. The software routine may also be
stored and/or executed by a second CPU (not shown) that is remotely
located from the hardware being controlled by the CPU 452.
[0052] Referring back to FIG. 2, in some embodiments, the module
102D may comprise an exhaust 221 coupled to a portion of the
enclosure 202 opposite the gas inlet 208 (e.g. the bottom 204) to
facilitate the removal gases from the enclosure 202 via passageways
233 formed in the bottom 204 of the enclosure 202.
[0053] Referring to FIG. 3, in some embodiments, the module 102D
may include one or more heating lamps (two heating lamps 302, 304
shown) coupled to the sides 306, 308 of the enclosure 202. The
heating lamps 302, 304 provide radiant heat into to enclosure 202
via the windows 214. The heating lamps 302, 304 may be any type of
heating lamp suitable to provide sufficient radiant heat into the
enclosure to perform a desired portion of a process within the
module 102D. For example, in some embodiments, the heating lamps
302, 304 may be linear lamps or zoned linear lamps capable of
providing radiant heat at a wavelength of about 0.9 microns, or in
some embodiments, about 2 microns. The wavelengths used for lamps
in various modules may be selected based upon the desired
application. For example, the wavelength may be selected to provide
a desired filament temperature. Low wavelength bulbs are less
expensive, use less power, and can be used for preheating. Longer
wavelength bulbs provide high power to facilitate providing higher
process temperatures, for example, for deposition processes.
[0054] In some embodiments, Infrared (IR) lamps may be provided in
one or more zones to provide heat energy to the substrate carriers
and ultimately to the substrates. Portions of the chamber where no
deposition is desired, such as the windows, may be fabricated of
materials that will not absorb IR light energy and heat up. Such
thermal management keeps deposition substantially contained to
desired areas. The one or more zones of IR lamps, for example in
horizontal bands from top to bottom of sides of the module,
facilitate controlling vertical temperature gradients to compensate
for depletion effects or other vertical non-uniformities of
deposition or other processing. In some embodiments, temperature
can also be modulated over time as well as between zones. This type
of granular temperature control, in addition to the gas injection
modulation described above with respect to FIG. 4, or combinations
thereof, can facilitate control of substrate processing results
from top to bottom of the substrates as well as lateral edge to
edge (for example, a thickness of a deposited film or uniformity of
dopant concentration and/or depth).
[0055] FIG. 5 depicts at least one exemplary embodiment of a
substrate carrier 502 that may be used with embodiments of the
present invention described herein. The substrate carrier 502 may
support two or more substrates and carry the two or more substrates
through the indexed inline substrate processing tool 100 or to a
cluster substrate processing tool (not shown). In some embodiments,
the substrate carrier 502 may generally include a base 512 and a
pair of opposing substrate supports 508, 510. One or more
substrates, (substrate 504, 506 shown in FIG. 5) may be disposed on
each of the substrate supports 508, 510 for processing. In some
embodiments, the substrate supports 508, 510 are secured on
substrate carrier 502 and may be held at an acute angle with
respect to each other, with the substrates facing each other and
defining a reaction zone therebetween. For example, in some
embodiments the substrate supports 508, 510 are held at an angle of
about between 2 degrees and 10 degrees from vertical.
[0056] The base 512 may be fabricated from any material suitable to
support the substrate supports 508, 510 during processing, for
example such as graphite. In some embodiments, a first slot 526 and
a second slot 528 may be formed in the base 512 to allow for the
substrate supports 508, 510 to be at least partially disposed
within the first slot 526 and second slot 528 to retain the
substrate supports 508, 510 in a desired position for processing.
In some embodiments, the substrate supports 508, 510 are generally
slightly angled outwardly such that the substrate supporting
surfaces generally oppose each other and are arranged in a "v"
shape. In some embodiments, the base 512 is fabricated from an
insulating material and may be either clear or opaque quartz or a
combination of clear and opaque quartz for temperature
management.
[0057] A channel 514 is disposed in a bottom surface 527 of the
base 512 and an opening 518 is disposed through the base 512 from a
top surface 529 of the base 512 to the channel 514 to form a path
for one or more gases to flow through the base 512. For example,
when the substrate carrier 502 is disposed in a module, such as the
module 102D described above, the opening 518 and channel 514
facilitates a flow of gas from a gas inlet (e.g., gas inlet 208
described above) to an exhaust of the module (e.g., exhaust 221 of
module 102D described above). The carriage may be fabricated from
quartz with the exhaust and cleaning channels machined into the
quartz or a metal base disposed below the quartz. A baffle may be
provided to facilitate evening out the flow through the base
512.
[0058] In some embodiments, the base 512 may include a conduit 516
disposed within the base 512 and circumscribing the channel 514.
The conduit 516 may have one or more openings formed along the
length of the conduit 516 to fluidly couple the conduit 516 to the
channel 514 to allow a flow of gas from the conduit 516 to the
channel 514. In some embodiments, while the substrate carrier 502
is disposed in a module, a cleaning gas may be provided to the
conduit 516 and channel 514 to facilitate removal of deposited
material from the channel 514. The cleaning gases may be provided
proximate one or more exhausts to prevent deposition of process
byproducts within the exhaust, thereby reducing downtime necessary
for cleaning//maintenance. The cleaning gas may be any gas suitable
to remove a particular material from the module. For example, in
some embodiments the cleaning gas may comprise one more chlorine
containing gases, such as hydrogen chloride (HCl), chlorine gas
(Cl.sub.2), or the like. Alternatively, in some embodiments, an
inert gas may be provided to the conduit 516 and channel 514 to
minimize deposition of material on the channel 514 by forming a
barrier between the exhaust gases flowing through the channel and
the surfaces of the channel.
[0059] The substrate supports 508, 510 may be fabricated from any
material suitable to support a substrate 504, 506 during
processing. For example, in some embodiments, the substrate
supports 508, 510 may be fabricated from graphite. In such
embodiments, the graphite may be coated, for example with silicon
carbide (SiC), to provide resistance to degradation and/or to
minimize substrate contamination.
[0060] The opposing substrate supports 508, 510 comprise respective
substrate support surfaces 520, 522 that extend upwardly and
outwardly from the base 512. Thus, when substrates 504, 506 are
disposed on the substrate supports 508, 510, a top surface 505, 507
of each of the substrates 504, 506 face one another. Facing the
substrates 504, 506 toward one another during processing
advantageously creates a radiant cavity between the substrates
(e.g. in the area 524 between the substrate supports 508, 510) that
provides an equal and symmetrical amount of heat to both substrates
504, 506, thus promoting process uniformity between the substrates
504, 506.
[0061] In some embodiments, during processing, process gases are
provided to the area 524 between the substrate supports 508, 510
while a heat source disposed proximate a back side 530, 532 of the
substrate supports 508, 510 (e.g., the heating lamps 302, 304
described above) provides heat to the substrates 504, 506.
Providing the process gases to the area 524 between the substrate
supports 508, 510 advantageously reduces exposure of the process
gases to interior components of the modules, thus reducing material
deposition on cold spots within the modules (e.g., the walls of the
modules, windows, or the like) as compared to conventional
processing systems that provide process gases between a heat source
and substrate support. In addition, the inventor has observed that
by heating the substrates 504, 506 via the back side 530, 532 of
the substrate supports 508, 510 any impurities within the module
will deposit on the back side 530, 532 of the substrate supports
508, 510 and not the substrates 504, 506, thereby advantageously
allowing for the deposition of materials having high purity and low
particle count atop the substrates 504, 506.
[0062] In operation of the indexed inline substrate processing tool
100 as described in the above figures, the substrate carrier 502
having a first set of substrates disposed in the substrate carrier
502 (e.g. substrates 504, 506) is provided to a first module (e.g.
first module 102A). When present, a barrier (e.g., barrier 118 or
barrier 219) on the first side and/or the second side of the first
module may be closed or turned on to facilitate isolating the first
module. A first portion of a process (e.g., a purge step of a
deposition process) may then be performed on the first set of
substrates. After the first portion of the process is complete, a
second substrate carrier having a second set of substrates disposed
in a second substrate carrier is provided to the first module. As
the second substrate carrier is provided to the first module, the
second substrate carrier pushes the first carrier to the second
module (e.g., the second module 102B). The first portion of the
process is then performed on the second set of substrates in the
first module while a second portion of the process is performed on
the first set of substrates in the second module. The addition of
subsequent substrate carriers repeats to provide each substrate
carrier to a fixed position (i.e., within a desired module), thus
providing a mechanical indexing of the substrate carriers. As the
process is completed in the substrate carriers may be removed from
the indexed inline substrate processing tool 100 via an unload
module (e.g., unload module 106).
[0063] While the foregoing is directed to embodiments of the
present invention, other and further embodiments of the invention
may be devised without departing from the basic scope thereof.
* * * * *