U.S. patent application number 12/939002 was filed with the patent office on 2011-02-24 for batch processing platform for ald and cvd.
Invention is credited to Adam Brailove, Andrew Constant, Nir Merry, Efrain Quiles, Michael R. Rice, Gary J. Rosen, Vinay K. Shah, Aaron Webb, Joseph Yudovsky.
Application Number | 20110041764 12/939002 |
Document ID | / |
Family ID | 38846399 |
Filed Date | 2011-02-24 |
United States Patent
Application |
20110041764 |
Kind Code |
A1 |
Webb; Aaron ; et
al. |
February 24, 2011 |
BATCH PROCESSING PLATFORM FOR ALD AND CVD
Abstract
A batch processing platform used for ALD or CVD processing is
configured for high throughput and minimal footprint. In one
embodiment, the processing platform comprises an atmospheric
transfer region, at least one batch processing chamber with a
buffer chamber and staging platform, and a transfer robot disposed
in the transfer region wherein the transfer robot has at least one
substrate transfer arm that comprises multiple substrate handling
blades. The platform may include two batch processing chambers
configured with a service aisle disposed therebetween to provide
necessary service access to the transfer robot and the deposition
stations. In another embodiment, the processing platform comprises
at least one batch processing chamber, a substrate transfer robot
that is adapted to transfer substrates between a FOUP and a
processing cassette, and a cassette transfer region containing a
cassette handler robot. The cassette handler robot may be a linear
actuator or a rotary table.
Inventors: |
Webb; Aaron; (Austin,
TX) ; Brailove; Adam; (Gloucester, MA) ;
Yudovsky; Joseph; (Campbell, CA) ; Merry; Nir;
(Mountain View, CA) ; Constant; Andrew;
(Cupertino, CA) ; Quiles; Efrain; (San Jose,
CA) ; Rice; Michael R.; (Pleasanton, CA) ;
Rosen; Gary J.; (San Carlos, CA) ; Shah; Vinay
K.; (San Mateo, CA) |
Correspondence
Address: |
PATTERSON & SHERIDAN, LLP - - APPM/TX
3040 POST OAK BOULEVARD, SUITE 1500
HOUSTON
TX
77056
US
|
Family ID: |
38846399 |
Appl. No.: |
12/939002 |
Filed: |
November 3, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11426563 |
Jun 26, 2006 |
7833351 |
|
|
12939002 |
|
|
|
|
Current U.S.
Class: |
118/715 ;
414/217; 414/222.01; 414/225.01 |
Current CPC
Class: |
Y10S 414/14 20130101;
H01L 21/67757 20130101; C23C 16/54 20130101; H01L 21/67769
20130101; C23C 16/4583 20130101; H01L 21/67173 20130101; H01L
21/67742 20130101 |
Class at
Publication: |
118/715 ;
414/222.01; 414/217; 414/225.01 |
International
Class: |
H01L 21/677 20060101
H01L021/677; C23C 16/00 20060101 C23C016/00 |
Claims
1. A substrate processing apparatus, comprising: a substrate
processing chamber; a buffer chamber positioned adjacent to the
substrate processing chamber; a processing cassette that is adapted
to support two or more substrates at a first spacing, wherein the
processing cassette is transferable between the buffer chamber and
the substrate processing chamber; a staging cassette that is
adapted to support two or more substrates at the first spacing; and
a transfer robot adapted to transfer a substrate between a
substrate transport pod and the staging cassette using a single
substrate handling blade, and to transfer substrates between the
staging cassette and the processing cassette using multiple
substrate handling blades.
2. The apparatus of claim 1, further comprising a factory interface
having: an atmospheric transfer region in which the staging
cassette and the transfer robot are disposed; a filtration unit
that is adapted to provide filtered air to the atmospheric transfer
region; and at least one load station for mounting the substrate
transport pod adjacent the atmospheric transfer region, wherein the
at least one load station is further adapted to open the substrate
transport pod so that the interior of the substrate transport pod
is in fluid communication with the atmospheric transfer region, and
wherein the substrate transport pod is adapted to contain two or
more substrates horizontally at a second spacing.
3. The apparatus of claim 1, wherein the transfer robot is further
adapted to remain translationally stationary while transferring one
or more substrates between the processing cassette and the staging
cassette.
4. The apparatus of claim 1, further comprising: a second substrate
processing chamber; a second buffer chamber positioned adjacent to
the second substrate processing chamber; a second processing
cassette that is adapted to support two or more substrates at the
first spacing, wherein the second processing cassette is
transferable between the second buffer chamber and the second
substrate processing chamber; and a second staging cassette that is
adapted to support two or more substrates at the first spacing,
wherein the transfer robot is further adapted to transfer
substrates between the second staging cassette and the second
processing cassette using the multiple substrate handling
blades.
5. The apparatus of claim 4, wherein the transfer robot is further
adapted to transfer substrates between the first processing
cassette and the second staging cassette using the multiple
substrate handling blades.
6. The apparatus of claim 1, wherein the multiple substrate
handling blades are fixed-pitch substrate handling blades.
7. The apparatus of claim 1, further comprising: a fluid delivery
system that is in fluid communication with an internal process
volume of the substrate processing chamber, wherein the fluid
delivery system is adapted to deliver a precursor-containing fluid
to the internal process volume so that a chemical vapor deposition
(CVD) or an atomic layer deposition (ALD) process can be performed
on one or more substrates positioned therein; and a facilities
tower proximate the substrate processing chamber, wherein the
facilities tower contains precursor-containing ampoules, and
wherein the fluid delivery system fluidly couples the facilities
tower to the substrate processing chamber by means of an overhead
rack.
8. The apparatus of claim 1, further comprising: a vertical lift
mechanism adapted to transfer a processing cassette into and out of
the substrate processing chamber.
9. The apparatus of claim 1, wherein the transfer robot has: a
two-bar linkage arm; and a motion assembly that is adapted to
position the two-bar linkage arm along a linear path, wherein the
linear path contains locations proximate the at least one load
station and the substrate processing chamber.
10. The apparatus of claim 1, further comprising: a second
substrate processing chamber; and a service aisle that is disposed
between the first and the second substrate processing chambers and
is adapted to provide all necessary service access to the transfer
robot and the first and second processing chambers.
11. The apparatus of claim 10, further comprising: a first load
station and a second load station, wherein the first load station
is proximate the first substrate processing chamber and the second
load station is proximate the second substrate processing
chamber.
12. The apparatus of claim 11, further comprising: a second
transfer robot disposed in the atmospheric transfer region
proximate the second load station and the second substrate
processing chamber and adapted to transfer a substrate between the
second load station and the second substrate processing chamber,
wherein the second transfer robot has at least one substrate
transfer arm that comprises multiple substrate handling blades, and
wherein the first transfer robot is proximate the first load
station and the first substrate processing chamber.
13. A substrate processing apparatus, comprising: a substrate
processing chamber; a processing cassette that is adapted to
support two or more substrates; a cassette handler robot adapted to
transfer the processing cassette between a staging platform and the
substrate processing chamber; a substrate transfer robot that is
adapted to transfer substrates between a substrate transport pod
and the processing cassette; a buffer chamber having one or more
walls that form an internal volume, wherein the internal volume is
positioned below the substrate processing chamber; and a cassette
transfer region in which the staging platform is disposed that is
generally maintained at atmospheric pressure.
14. The apparatus of claim 13, wherein the cassette handler robot
is a linear translator and wherein the linear translator is adapted
to contain a lift mechanism.
15. The apparatus of claim 13, wherein the cassette handler robot
is a rotary table.
16. The apparatus of claim 15, wherein the first processing
cassette is on a staging platform and the rotary table is adapted
to: receive a second processing cassette from a lift mechanism;
rotatably swap the positions of the first processing cassette and
the second processing cassette; and position the first processing
cassette to enable transferal of the first processing cassette
between the substrate processing chamber and the cassette transfer
region by use of the lift mechanism.
17. The apparatus of claim 16, wherein the staging platform is on
the rotary table.
18. The apparatus of claim 17, wherein the rotary table is
contained in the internal volume.
19. The apparatus of claim 18, wherein the rotary table is adapted
to horizontally translate the first processing cassette and the
second processing cassette.
20. The apparatus of claim 13, further comprising a factory
interface having: an atmospheric transfer region in which the
staging cassette and the transfer robot are disposed; a filtration
unit that is adapted to provide filtered air to the atmospheric
transfer region; and at least one load station for mounting the
substrate transport pod adjacent the atmospheric transfer region,
wherein the at least one load station is further adapted to open
the substrate transport pod so that the interior of the substrate
transport pod is in fluid communication with the atmospheric
transfer region, and wherein the substrate transport pod is adapted
to contain two or more substrates horizontally at a second spacing.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of co-pending U.S. patent
application Ser. No. 11/426,563, filed Jun. 26, 2006, which is
herein incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] Embodiments of the present invention generally relate to an
apparatus for processing substrates. More particularly, the
invention relates to a batch processing platform for performing
atomic layer deposition (ALD) and chemical vapor deposition (CVD)
on substrates.
[0004] 2. Description of the Related Art
[0005] The process of forming semiconductor devices is commonly
conducted in substrate processing platforms containing multiple
chambers. In some instances, the purpose of a multi-chamber
processing platform or cluster tool is to perform two or more
processes on a substrate sequentially in a controlled environment.
In other instances, however, a multiple chamber processing platform
may only perform a single processing step on substrates; the
additional chambers are intended to maximize the rate at which
substrates are processed by the platform. In the latter case, the
process performed on substrates is typically a batch process,
wherein a relatively large number of substrates, e.g. 25 or 50, are
processed in a given chamber simultaneously. Batch processing is
especially beneficial for processes that are too time-consuming to
be performed on individual substrates in an economically viable
manner, such as for ALD processes and some chemical vapor
deposition (CVD) processes.
[0006] The effectiveness of a substrate processing platform, or
system, is often quantified by cost of ownership (COO). The COO,
while influenced by many factors, is largely affected by the system
footprint, i.e., the total floor space required to operate the
system in a fabrication plant, and system throughput, i.e., the
number of substrates processed per hour. Footprint typically
includes access areas adjacent the system that are required for
maintenance. Hence, although a substrate processing platform may be
relatively small, if it requires access from all sides for
operation and maintenance, the system's effective footprint may
still be prohibitively large.
[0007] The semiconductor industry's tolerance for process
variability continues to decrease as the size of semiconductor
devices shrink. To meet these tighter process requirements, the
industry has developed a host of new processes which meet the
tighter process window requirements, but these processes often take
a longer time to complete. For example, for forming a copper
diffusion barrier layer conformally onto the surface of a high
aspect ratio, 65 nm or smaller interconnect feature, it may be
necessary to use an ALD process. ALD is a variant of CVD that
demonstrates superior step coverage compared to CVD. ALD is based
upon atomic layer epitaxy (ALE) that was originally employed to
fabricate electroluminescent displays. ALD employs chemisorption to
deposit a saturated monolayer of reactive precursor molecules on a
substrate surface. This is achieved by alternating the pulsing of
an appropriate reactive precursors into a deposition chamber. Each
injection of a reactive precursor is typically separated by an
inert gas purge to provide a new atomic layer to previous deposited
layers to form a uniform layer on the substrate. The cycle is
repeated to form the layer to a desired thickness. The biggest
drawback with ALD techniques is that the deposition rate is much
lower than typical CVD techniques by at least an order of
magnitude. For example, some ALD processes can require a chamber
processing time from about 10 to about 200 minutes to deposit a
high quality layer on the surface of the substrate. While forced to
choose such processes due to device performance requirements, the
cost to fabricate the devices in a conventional single substrate
processing chamber will increase due to the low substrate
throughput. Hence, a batch processing approach is typically taken
when implementing such processes to make them economically
viable.
[0008] Therefore, there is a need for a batch processing platform
for ALD and CVD applications wherein throughput is maximized and
footprint is minimized.
SUMMARY OF THE INVENTION
[0009] Embodiments of the present invention provide a batch
processing platform used for ALD or CVD processing of substrates
with minimized footprint and high throughput. In one embodiment,
the processing platform comprises an atmospheric transfer region,
at least one batch processing chamber with a buffer chamber and
staging platform, and a transfer robot disposed in the transfer
region wherein the transfer robot has at least one substrate
transfer arm that comprises multiple substrate handling blades. The
transfer robot may be adapted to transfer substrates between a
processing cassette and a staging cassette and may further be
adapted to be a two bar linkage robot. The platform may include two
batch processing chambers configured with a service aisle disposed
therebetween to provide necessary service access to the transfer
robot and the deposition stations. A fluid delivery system may be
in fluid communication with the internal process volume of the at
least one batch processing chamber and may be positioned in a
facilities tower proximate thereto. A FOUP (Front Opening Uniform
Pod) management system may be positioned adjacent the platform.
[0010] In another embodiment the processing platform comprises at
least one batch processing chamber, a substrate transfer robot that
is adapted to transfer substrates between a FOUP and a processing
cassette, and a cassette transfer region containing a cassette
handler robot. The cassette transfer region may be maintained at
atmospheric pressure and the cassette handler robot may be a linear
actuator with vertical lift capability or a rotary table.
Alternatively, the cassette transfer region may be maintained at a
pressure below atmospheric pressure and may further comprise one or
more load locks adapted to support the processing cassette
proximate the substrate transfer robot. In this aspect, the
cassette handler robot may be a linear actuator with vertical lift
capability or a rotary table with vertical lift capability. In one
configuration, the platform comprises two load locks and two batch
processing chambers and the rotary table may be adapted to
rotatably position a cassette under each load lock and under each
deposition chamber and to vertically transfer cassettes between the
cassette transfer region and the deposition chambers and between
the cassette transfer region and the load locks. A fluid delivery
system may be in fluid communication with the internal process
volume of the at least one batch processing chamber and may be
positioned in a facilities tower proximate thereto. A FOUP
management system may be positioned adjacent the platform.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] So that the manner in which the above recited features of
the present invention can be understood in detail, a more
particular description of the invention, briefly summarized above,
may be had by reference to embodiments, some of which are
illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only typical embodiments of
this invention and are therefore not to be considered limiting of
its scope, for the invention may admit to other equally effective
embodiments.
[0012] FIG. 1A is a schematic plan view of a batch processing
platform that uses a multiple arm robot for substrate
transfers.
[0013] FIG. 1B is a perspective view of the batch processing system
of FIG. 1A.
[0014] FIG. 1C is a schematic vertical cross-sectional view of a
batch processing system illustrating the factory interface,
reactors, buffer chambers, and staging platforms.
[0015] FIG. 1D illustrates a schematic plan view of a batch
processing system configured with two batch processing stations,
each served by a two-cassette rotary table.
[0016] FIG. 1E is a cross-sectional side view of a batch processing
station.
[0017] FIG. 1F illustrates one configuration of a robot assembly
that may be used in a factory interface.
[0018] FIG. 1G illustrates a configuration of a robot hardware
assembly containing a transfer robot that may be adapted to
transfer a single substrate at a time.
[0019] FIG. 1H illustrates one configuration of a robot hardware
assembly that contains two transfer robots that are positioned in
an opposing orientation to each other.
[0020] FIG. 1I illustrates a five blade robot arm.
[0021] FIG. 1J illustrates a preferred configuration of robot
hardware assembly that includes a single blade transfer robot and a
multiple blade transfer robot.
[0022] FIG. 1K illustrates the clearance region of a cartesian
robot.
[0023] FIG. 1L illustrates the clearance region of a conventional
robot.
[0024] FIG. 1M illustrates a cross-sectional side view of one
configuration of a two bar linkage robot.
[0025] FIG. 1N illustrates a schematic diagram of one configuration
of a precursor delivery system.
[0026] FIG. 1O is a perspective view of a batch processing system
with a precursor delivery system positioned on top of the
system.
[0027] FIG. 1P is a side view of an exemplary stocker
apparatus.
[0028] FIG. 1Q is a front elevation view of the stocker apparatus
of FIG. 1P.
[0029] FIG. 2A is a schematic plan view of a batch processing
platform.
[0030] FIG. 2B is a schematic side view of a batch processing
platform.
[0031] FIG. 2C is a perspective view of a batch processing
system.
[0032] FIG. 2D is a perspective view of a batch processing
system.
[0033] FIG. 3A is a schematic plan view of a batch processing
platform.
[0034] FIG. 3B is a schematic side view of a batch processing
platform.
[0035] FIG. 4A is a schematic plan view of a batch processing
platform.
[0036] FIG. 4B is a schematic side view of a batch processing
platform.
[0037] FIG. 5 is a schematic plan view of a batch processing
platform.
DETAILED DESCRIPTION
[0038] A batch processing platform for ALD and CVD applications is
provided, wherein throughput is maximized and footprint is
minimized. In one embodiment, throughput is improved by using a
multiple arm robot to transfer substrates. In another embodiment, a
cassette handler robot is used to transfer entire cassettes to
improve throughput.
Multiple Arm Robot Platform
[0039] In this embodiment, a robot with multiple arms transfers
substrates between a staging cassette and a processing cassette
using an arm configured with multiple blades to reduce transfer
times therebetween. Because a processing chamber is idle during
substrate transfers, it is beneficial for system throughput to
minimize the time required for transferring substrates into and out
of a processing cassette. The robot also transfers substrates
between a substrate transport pod and the staging cassette using
another arm configured with a single blade to accommodate the
difference in substrate spacing between the pod and the staging
cassette. Configurations include a cartesian robot-based platform
as well as a configuration with two batch processing chambers and a
common access space therebetween that allows all components of the
platform to be accessed for maintenance without side access to the
platform.
[0040] FIG. 1A is a schematic plan view of one aspect of the
invention, a batch processing platform using a multiple arm robot
for substrate transfers, hereinafter referred to as system 100.
System 100 includes one or more batch processing stations 101A,
101B, a system controller 111, a factory interface (FI) 102,
containing a transfer robot assembly 103 and one or more load
stations 104A-C, and a process fluid delivery system, which may be
contained in a facilities tower 130. For illustrative purposes,
transfer robot assembly 103 is illustrated in three positions
simultaneously, i.e., adjacent load stations 104A-C, adjacent
reactor 121A and adjacent reactor 121B. The batch processing
stations 101A, 101B are disposed adjacent FI 102 and proximate each
other to minimize the overall footprint of batch processing
platform 100 and the distance necessary for transfer robot assembly
103 to travel when transferring substrates between load stations
104A-C and batch processing stations 101A, 101B. Two batch
processing stations 101A, 101B are illustrated in FIG. 1A, however
additional stations may be added easily. A facilities tower 130 may
be positioned a service distance 137 from batch processing station
101B and FI 102 and may be connected to other components of system
100 via an overhead rack 140. Service distance 137 allows access
door 135A to be opened for servicing transfer robot assembly
103.
[0041] Batch processing stations 101A, 101B may be configured to
perform the same batch process simultaneously on different groups
of substrates, or they may be configured to perform two different
batch processes sequentially on the same group of substrates. In
the former configuration, the starting time for substrate
processing in each batch processing station may be staged, i.e.,
alternated, to minimize idle time associated with the transfer of
substrates to and from batch processing stations 101A, 101B;
transfer robot assembly 103 is only required to load and unload one
batch processing station at a time. In the latter configuration, a
group of substrates undergoes a first batch process in one batch
processing station and then undergoes a second batch process in the
other batch processing station. Alternatively, system 100 may be
configured with a combination of batch processing stations and
single-substrate processing stations. This configuration of system
100 is particularly useful when an unstable batch film requires
some form of post-processing, such as a capping process, since the
batch-processed substrates may immediately undergo the desired
post-processing.
[0042] In general operation, substrates are typically transported
to system 100 in FOUP's, that are positioned on the load stations
104A-C. Transfer robot assembly 103 may transfer a first batch of
substrates to a staging cassette adjacent the batch processing
station while the batch processing station is processing a second
batch of substrates in a processing cassette. Transfer robot
assembly 103 may perform the transfer between FOUP's and staging
platforms with a robot arm configured with a single blade. After
processing, substrates may be swapped between the staging cassette
and the desired processing cassette by transfer robot assembly 103
using a robot arm configured with multiple blades. If any
single-substrate processing chambers are present on system 100,
transfer robot assembly 103 transfers substrates between the
single-substrate processing chambers and the appropriate staging
platform using a robot arm configured with a single blade.
[0043] In a configuration of system 100 in which sequential batch
processes are performed on the same group of substrates, substrates
may be transferred to a batch processing station from a first
staging cassette prior to processing and then transferred to a
second staging cassette after processing. For example, transfer
robot assembly 103 may transfer a group of substrates from a
staging cassette 123A to batch processing station 101A for a first
batch process. Upon completion of the first batch process, transfer
robot assembly 103 transfers the group of substrates from batch
processing station 101A to staging cassette 123B. When batch
processing station 101B is available for processing, transfer robot
assembly 103 then transfers the group of substrates from staging
cassette 123B to batch processing station 101B for the second batch
process. As noted above, a robot arm configured with multiple
blades is used for transfers between staging cassettes and batch
processing stations, since there is no difference in substrate
spacing therebetween.
Batch Processing Stations
[0044] FIG. 1B is a perspective view of system 100 with access
panels 120A, 120B and facilities tower 130 removed for clarity.
Referring to FIGS. 1A and 1B, batch processing station 101A
includes a reactor 121A, containing an internal process volume 127,
a buffer chamber 122A positioned adjacent reactor 121A, and a
staging platform 123A adapted to support a staging cassette (not
shown) proximate batch processing chamber 121A. Similarly, batch
processing station 101B includes a reactor 121B, a buffer chamber
122B, and a staging platform 123B adapted to support a staging
cassette (not shown) proximate batch processing chamber 121 B.
[0045] FIG. 1C is a schematic vertical cross-sectional view of
system 100 illustrating FI 102, reactors 121A, 121B, buffer
chambers 122A, 122B, and staging platforms 123A, 123B. Preferably,
and as illustrated in FIGS. 1B and 1C, buffer chambers 122A, 122B
are not only adjacent to, but also vertically aligned with reactors
121A, 121B, respectively, minimizing the footprint of batch system
100. In the configuration illustrated in FIGS. 1B, 1C, buffer
chambers 122A, 122B are positioned directly below reactors 121A,
121B, respectively. Buffer chambers 122A, 122B are adapted to act
as vacuum load locks for the loading and unloading of a processing
cassette 146 into and out of reactors 121A, 121B, respectively.
Buffer chambers 122A, 122B are fluidly coupled to a vacuum source.
The vacuum source may be a remote vacuum source or a vacuum pump
171 contained inside system 100. It is important to minimize the
time required for pumping down and venting buffer chambers 122A,
122B, because reactors 121A, 121B are idle during buffer chamber
pumping and venting. To that end, buffer chambers 122A, 122B are
further adapted to contain the minimum volume necessary to contain
the processing cassette in order to speed the pumping and venting
process. For example, for a processing cassette adapted to support
circular substrates in a vertically aligned column, buffer chambers
122A, 122B are preferably configured as cylindrical chambers with a
minimal vertical clearance above and below the processing cassette
and with a minimal radial clearance around the processing cassette
and substrates therein, as depicted in FIG. 1B. Buffer chambers
122A, 122B both further include a lift mechanism 600, transfer
openings 36, 37, and vacuum-tight doors 156, 157. Lift mechanism
600 may be pneumatic actuator, a stepper motor, or other vertical
actuators known in the art.
[0046] In operation, processing cassette 146 is loaded with
substrates W from staging cassette 186 via transfer robot assembly
103 while a buffer chamber (in this example, buffer chamber 122A)
is vented to atmosphere and transfer opening 36 is open to transfer
region 135. For clarity, only one robot arm 162, which is
configured with five blades 161 is illustrated in FIG. 1C. The
substrate loading/unloading process is described below in
conjunction with FIGS. 1F-1I. Vacuum-tight door 156 is closed and
buffer chamber 122A is pumped down to the same level of vacuum
present in process volume 127, generally between about 0.5 and 20
Torr. Vacuum-tight door 157 is then opened and lift mechanism 600
transfers processing cassette 146 into process volume 127 for ALD
or CVD processing of substrates W. For some ALD and CVD processes,
it is desirable to pressure cycle substrates W in buffer chamber
122A, i.e., buffer chamber 122A is alternately pumped down to
process pressure and vented with a very dry gas to remove residual
moisture adsorbed onto the surfaces of substrates W and processing
cassette 146. In one configuration, lift mechanism 600 lowers back
to buffer chamber 122A and vacuum-tight door 157 closes during
processing in process volume 127. After processing is complete,
lift mechanism 600 transfers processing cassette 146 back to buffer
chamber 122A and vacuum-tight door 157 closes, isolating process
volume 127 from buffer chamber 122A. Buffer chamber 122A is then
vented to atmospheric pressure and substrates W are transferred to
staging cassette 186 for cooling and subsequent removal from system
100.
[0047] Isolating process volume 127 from buffer chamber 122A with
vacuum-tight door 157 while transferring substrates W to staging
cassette 186 allows process volume 127 to remain as close as
possible to process temperature and pressure between batches of
substrates. This is beneficial to process repeatability and
throughput since little time is required for process conditions in
process volume 127 to stabilize to desired conditions. Process
volume 127 for batch processing chambers may be relatively large to
accommodate a typical processing cassette 146, for example, on the
order of 1 m in height. Because of this, stabilization of the
pressure and temperature in process volume 127 can be
time-consuming after being vented to atmospheric pressure. Hence,
chamber idle time--in this case stabilization time--is reduced
significantly by isolating process volume 127 during substrate
transfers between processing cassette 146 and staging cassette 186.
In addition, fewer contaminants are able to enter process volume
127 as a result of transferring processing cassette 146 between
buffer chamber 122A and reactor 121A.
[0048] In one configuration, lift mechanism 600 may also be adapted
to assist in servicing the reactor. Referring to FIG. 1B, lift
mechanism 600 may be used to lower difficult-to-access components
of reactor 121A into buffer chamber 122A for easy removal from
access panel 120A. Improved serviceability reduces system downtime
during maintenance procedures, improving COO.
[0049] Reactors 121A, 121B are adapted to perform a CVD and/or an
ALD process on substrates W supported on a processing cassette 146
and contained therein. A more detailed description of an ALD or CVD
reactor that may be contained in some configurations of the
invention may be found in commonly assigned U.S. patent application
Ser. No. 11/286,063, filed on Nov. 22, 2005, which is hereby
incorporated by reference in its entirety to the extent not
inconsistent with the claimed invention. Reactors 121A, 121B are
fluidly coupled to a process fluid delivery system that is adapted
to provide the necessary appropriate reactive precursor and other
process fluids. Preferably, the process fluid delivery system is
contained in a facilities tower 130 and coupled to reactors 121A,
121B via an overhead rack 140, illustrated in FIG. 1A. Facilities
tower 130 is described below in conjunction with FIG. 1N.
Electrical and other facilities, such as system controller 111 may
also be located in facilities tower 130. Alternatively, the fluid
delivery system may be positioned remotely in another area of the
fabrication plant and may be fluidly coupled to reactors 121A, 121B
via underfloor connections (not shown).
[0050] Referring to FIG. 1C, staging platforms 123A, 123B are
positioned in FI 102 and are each adapted to support a staging
cassette 186 proximate reactors 121A, 121B, respectively.
Typically, substrates are supported in a sealable substrate
transport pod, hereinafter referred to as a front-opening uniform
pod (FOUP), at a lower density than during batch processing in an
ALD or CVD chamber, i.e., there is a 10 mm substrate-to-substrate
spacing in a FOUP vs. a 6 mm to 8 mm spacing in a processing
cassette 146. It is important to note that a staging cassette 186
supported proximate a batch processing chamber may be adapted to
support substrates at the identical substrate density at which
substrates are supported in a processing cassette 146, providing
substantial throughput and cost benefits. For example, a simple
single blade robot arm, such as that described below in conjunction
with FIG. 1G, may be used to transfer substrates between staging
cassettes 123A, 123B and load stations 104A-C. Although
transferring substrates therebetween with a multiple blade robot
arm is faster that with a single blade robot arm, there is
generally no throughput gain over single blade transfer of
substrates. This is because substrate transfers between staging
cassettes 123A, 123B and load stations 104A-C may take place
"off-line", i.e., while reactors 121A, 121B are processing
substrates. Transfer times that directly affect system throughput
are those between staging platforms 123A, 123B and buffer chambers
122A, 122B, as described above in conjunction with FIGS. 1A-C.
[0051] Because staging cassette 186 may be adapted to support
substrates at the identical substrate density at which substrates
are supported in processing cassette 146, substrate transfers may
be conducted therebetween with a multiple blade, fixed pitch robot,
such as that described below in conjunction with FIG. 1I. Multiple
blade robots greatly reduce substrate transfer time since multiple
substrates may be transferred at one time. System throughput may be
improved significantly thereby, since shorter transfer times reduce
reactor idle time.
[0052] Staging cassette 186 and processing cassette 146 may be
adapted to support a relatively large number of substrates, i.e.,
more than are typically contained in a standard FOUP. Because some
processes, e.g., ALD processes, are so time consuming, it is
beneficial for COO for as many substrates as practicable to be
processed in a single batch. Hence, staging cassette 186 and
processing cassette 146 are preferably adapted to support a batch
of between about 50 and about 100 substrates. Larger batches are
also possible, but the manipulation of cassettes so large in a
reliable and safe manner becomes increasingly problematic.
Processing cassette 146 may be constructed of any suitable high
temperature material such as, for instance, quartz, silicon
carbide, or graphite, depending upon desired process
characteristics
[0053] Staging platforms 123A, 123B may also serve as cooling
platforms on which substrates may cool after unloading from
reactors 121A, 121B. Typically, substrates unloaded from ALD and
CVD chambers are too hot (i.e., >100.degree. C.) to be loaded
directly into a standard FOUP. Staging platforms 123A, 123B may
also be adapted with a conventional robot vertical motion assembly
187, as shown in FIG. 1C. To minimize the complexity of system 100,
it is preferred that staging platforms 123A, 123B are stationary
components and the vertical motion required for substrate hand-offs
is carried out by transfer robot assembly 103.
[0054] In one configuration of system 100, a staging cassette 186
that is supported on staging platforms 123A, 123B may contain more
substrate support shelves 185 than processing cassette 146 disposed
in buffer chambers 122A, 122B. This allows substrates to be swapped
between staging cassette 186 and processing cassette 146 without
the use of a third substrate staging location and without the use
of an additional transfer robot assembly, such as second transfer
robot 86B (described below in conjunction with FIG. 1H). For
example, referring to FIG. 1C, processing cassette 146 has nine
substrate support shelves 185 and staging cassette 186 has nine
support shelves 185 plus one or more additional shelves 185A.
Hence, transfer robot assembly 103 may remove a processed substrate
W from processing cassette 146 and place it in the unused
additional shelf 185A. An unprocessed substrate is then removed
from staging cassette 186 by transfer robot assembly 103 to the now
empty support shelf 185 in processing cassette 146, leaving one of
support shelves 185 open in staging cassette 186. The above process
may then be repeated until all substrates originally in processing
cassette 146 have been swapped with the substrates originally in
staging cassette 186. In a similar configuration, when transfer
robot assembly 103 includes a multi-blade robot arm (described
below in conjunction with FIG. 1I) for transferring substrates
between staging cassette 186 and processing cassette 146, it is
preferred that the number of additional shelves 185A is equal to
the number of blades on the multi-blade robot arm of transfer robot
assembly 103. This allows the same substrate swap procedure
described above, but with multiple substrates being swapped at one
time.
[0055] In another configuration of system 100, staging cassette 186
may contain multiple additional shelves 185A for supporting dummy
substrates, i.e., non-production substrates, during batch
processing. Due to thermal non-uniformity and other factors,
substrates near the top and bottom of a processing cassette are
often not processed uniformly compared to the majority of
substrates in the processing cassette. The placement of one or more
dummy substrates in the top and bottom substrate support shelves of
a processing cassette may ameliorate this problem. The
non-production dummy substrates are placed in the top 1 to 5
substrate support shelves 185 and the bottom 1 to 5 support shelves
185 of processing cassette 146. Dummy substrates may be used for
multiple batch processes, e.g., about 5 or 10 times, before being
replaced, and therefore do not need to be removed from system 100
after each batch process is performed. To reduce the time required
to reload dummy substrates into processing cassettes, aspects of
the invention contemplate the storage of dummy substrates on
additional shelves 185A contained in staging cassette 186. Hence,
dummy substrates are stored in transfer region 135 in proximity to
the batch processing stations 101A, 101B, whenever batch processes
are not being performed therein. In addition to reducing the time
required to load dummy substrates into a processing cassette,
storage of dummy substrates on additional shelves 185A reduces the
number of FOUP's that need to be stored in the stocker 150 (shown
in FIG. 1B and described below in conjunction with FIGS. 1P and
1Q).
[0056] In one configuration, staging platforms 123A, 123B are each
adapted to serve as a two-cassette rotary table for rotatably
swapping a first processing cassette of unprocessed substrates with
a second processing cassette processed substrates. FIG. 1D
illustrates a schematic plan view of system 100 configured with two
batch processing stations 101A, 101B, each served by a two-cassette
rotary table 129A, 129B, respectively. In this configuration,
staging cassette 186 acts as the second processing cassette.
[0057] While a batch of substrates in processing cassette 146 are
being processed in the reactor 121A of batch processing station
101A, staging cassette 186 is being loaded with substrates from
load stations 104A-C. After processing is complete in reactor 121A,
processing cassette 146 is lowered onto rotary table 129A by a lift
mechanism (not shown for clarity). Rotary table 129A then rotates
180.degree., swapping the locations of processing cassette 146 and
staging cassette 186. The processed substrates cool in transfer
region 135 and are then transferred to one or more FOUP's
positioned on load stations 104A-C. Simultaneously, the lift
mechanism transfers staging cassette 186 into reactor 121A for
processing. Hence, no significant length of time is required to
transfer substrates from transfer region 135 to reactor 121A.
Rather than transferring individual substrates between a staging
cassette and a processing cassette, in this configuration of system
100 the staging and processing cassettes are simply swapped by
rotary table 129A. In one example, the batch processing stations
101A, 101B each include a buffer chamber for isolating reactors
121A, 121B as described above in conjunction with FIG. 1D.
[0058] In another configuration, rotary tables 129A, 129B are each
contained in a buffer chamber 128, as illustrated in FIG. 1E. FIG.
1E is a cross-sectional side view of a batch processing station
101A which includes a reactor 121A containing a processing cassette
146A and a buffer chamber 128 containing a two-cassette rotary
table 129A and a second processing cassette 146B. A lift mechanism
600A, in this case a vertical indexer robot, transfers cassettes
between rotary table 129A and reactor 121A. During processing of
processing cassette 146A, buffer chamber 128 is vented to
atmospheric pressure and a vacuum-tight door 156 opens to provide
access to second processing cassette 146B from transfer robot
assembly 103. After second processing cassette 146B is loaded with
substrates, vacuum-tight door 156 is closed and buffer chamber 128
is vented or pressure cycled in preparation for swapping second
processing cassette 146B with processing cassette 146A. This
configuration allows the speedy reloading of reactor 121A with a
processing cassette, minimizing reactor downtime. All pump-down and
venting of buffer chamber 128 take place while substrates are being
processed in reactor 121A.
Factory Interface
[0059] Referring back to FIG. 1C, the factory interface (FI) 102,
contains a transfer robot assembly 103, a transfer region 135, an
environmental control assembly 110 and one or more load stations
104A-C (shown in FIG. 1A). FI 102 maintains transfer region 135 as
a clean mini-environment, i.e., a localized, atmospheric pressure,
low-contaminant environment, via a fan-powered air filtration unit.
FI 102 is intended to provide a clean environment, i.e., transfer
region 135, in which a substrate may be transferred between a FOUP
positioned on any of load stations 104A-C and reactors 121A, 121B.
Recently processed substrates are also able to cool after
processing in the low-contamination environment of transfer region
135 prior to being transferred out of system 100 and into a
FOUP.
[0060] FIG. 1C is a schematic vertical cross-sectional view of
system 100 illustrating FI 102, reactors 121A, 121B, buffer
chambers 122A, 122B, and staging platforms 123A, 123B. For clarity,
load stations 104A-C are not shown. In one aspect, environmental
control assembly 110 contains a filtration unit 190 that may
contain a filter 191, such as a HEPA filter, and a fan unit 192.
The fan unit 192 is adapted to push air through the filter 191,
through transfer region 135, and out the base 193A of the FI 102.
FI 102 includes walls 193 to enclose transfer region 135 to better
provide a controlled environment to perform the substrate
processing steps. Generally the environmental control assembly 110
is adapted to control the air flow rate, flow regime (e.g., laminar
or turbulent flow) and particulate contamination levels in the
transfer region 135. In one aspect, the environmental control
assembly 110 may also control the air temperature, relative
humidity, the amount of static charge in the air and other typical
processing parameters that can be controlled by use of conventional
clean room compatible heating, ventilation, and air conditioning
(HVAC) systems known in the art.
[0061] Load stations 104A-C are adapted to support, open, and close
a FOUP or other sealable substrate transport pod placed thereon.
Hence, load stations 104A-C fluidly couple substrates contained in
a load station-supported FOUP to transfer region 135 without
exposing the substrates to contaminants that may be present outside
the FOUP and/or transfer region 135. This allows substrates to be
removed, replaced, and resealed in a FOUP in a clean and fully
automated manner.
Cartesian Robot
[0062] FIG. 1F illustrates one configuration of a robot assembly 11
that may be used as transfer robot assembly 103 in FI 102. The
robot assembly 11 generally contains a robot hardware assembly 85,
a vertical robot assembly 95 and a horizontal robot assembly 90. A
substrate can thus be positioned in any desired x, y and z position
in the transfer region 135 by the cooperative motion of the robot
hardware assemblies 85, vertical robot assembly 95 and horizontal
robot assembly 90, from commands sent by the system controller
111.
[0063] The robot hardware assembly 85 generally contains one or
more transfer robots 86 that are adapted to retain, transfer and
position one or more substrates by use of commands sent from the
system controller 111. In the configuration depicted in FIG. 1F,
two transfer robots 86 are included in robot hardware assembly 85.
In a preferred configuration, the transfer robots 86 are adapted to
transfer substrates in a horizontal plane, such as a plane that
includes the X and Y directions illustrated in FIGS. 1A and 1F, due
to the motion of the various transfer robot 86 components. Hence,
the transfer robots 86 are adapted to transfer a substrate in a
plane that is generally parallel to the substrate supporting
surface 87C (see FIG. 1M) of robot blade 87. The operation of one
configuration of transfer robots 86 is described below in
conjunction with FIG. 1M.
[0064] FIG. 1G illustrates a configuration of robot hardware
assembly 85 containing a transfer robot 86 that may be adapted to
transfer a single substrate W at a time. A single substrate
transfer capability for transfer robot assembly 103 is beneficial
to system 100 because it allows the transfer of substrates between
a FOUP disposed on one of load stations 104A-C and staging
platforms 123A, 123B despite the difference in substrate density
generally present between a standard FOUP and staging platforms
123A, 123B. Multiple blade transfer of substrates therebetween
necessitates a variable pitch robot blade, i.e., a multiple blade
robot arm with the capability to vary the distance, or pitch,
between substrates. Variable pitch robot blades, while known in the
art, are relatively complex, which may impact overall system
downtime and therefore COO.
[0065] FIG. 1H illustrates one configuration of robot hardware
assembly 85 that contains two transfer robots 86A, 86B that are
positioned in an opposing orientation to each other, i.e.,
vertically mirrored, so that the blades 87A-B (and first linkages
310A-310B) can be placed a small distance apart. The configuration
shown in FIG. 1H, i.e., an "over/under" type blade configuration,
may be advantageous, for example, where it is desired to "swap"
substrates, i.e., to remove a substrate from a location and
immediately replace it with another substrate with minimal robot
motions. For example, it is desirable to remove a processed
substrate from processing cassette 146 with transfer robot 86A and
immediately replace it with an unprocessed substrate that has
already been taken from staging cassette 186 and is available on
second transfer robot 86B. Because there is no need to transfer the
processed substrate to another location before loading the
unprocessed substrate, this substrate swap can take place without
necessitating robot hardware assembly 85 or robot assembly 11
leaving their basic positions, substantially improving system
throughput. This is particularly the case for system 100 during
transfer of substrates between staging platforms 123A, 123B and
buffer chambers 122A, 122B, respectively. The over/under blade
configuration illustrated in FIG. 1H allows unprocessed substrates
disposed on staging platforms 123A, 123B to be swapped with
processed substrates disposed in buffer chambers 122A, 122B
respectively. Hence, no additional staging/cooling location for
substrates is required to enable this substrate swap when the
over/under blade configuration, or variations thereof, is used.
This significantly reduces the footprint of system 100 while
minimizing the time reactors 121A, 121B are idle while processing
cassette 146 is being emptied and refilled with substrates.
[0066] In another configuration, robot hardware assembly 85 may
further include at least one multiple blade, fixed-pitch robot arm,
enabling swapping of multiple substrates between staging platforms
123A, 123B and buffer chambers 122A, 122B as described above. In
one example, transfer robot 86A includes a five blade robot arm
87H, as illustrated in FIG. 1I. In another example, transfer robot
86A and second transfer robot 86B both include a multiple blade
robot arm, enabling swapping of multiple substrates between staging
platforms 123A, 123B and buffer chambers 122A, 122B, respectively,
as described above in conjunction with FIG. 1H.
[0067] FIG. 1J illustrates a preferred configuration of robot
hardware assembly 85 of robot assembly 11, which includes a single
blade transfer robot 86C and a multiple blade transfer robot 86D.
Single blade transfer robot 86C may transfer substrates W between
load stations 104A-C and staging cassette 186. Multiple blade
transfer robot 86D may transfer substrates W between staging
cassette 186 and processing cassette 146.
[0068] It is important to note that the configuration of system
100, as illustrated in FIG. 1A, allows the transfer of substrates
between staging platforms 123A, 123B and buffer chambers 122A,
122B, respectively, without the need for horizontal translation of
vertical robot assembly 95 by horizontal robot assembly 90, which
substantially reduces transfer times. This configuration
significantly increases system throughput by minimizing processing
chamber idle time. Because reactors 121A, 121B are idle whenever
their respective processing cassette 146 is being unloaded, the
substrate transfer should be carried out as quickly as possible.
Eliminating the need for horizontal translation of vertical robot
assembly 95 during substrate transfer accomplishes this goal.
[0069] An additional advantage of the use of a cartesian robot, as
illustrated in FIGS. 1F-1J, is that a smaller system footprint is
required for substrate transfers to be carried out within transfer
region 135 compared to conventional substrate transfer robots, such
as a selective compliance assembly robot arm (SCARA). This is
illustrated by FIGS. 1K and 1L. The width W.sub.1, W.sub.2 of a
clearance region 90A that surrounds a transfer robot assembly 103
is minimized. Clearance region 90A is defined as a region adjacent
a substrate transferring robot, such as transfer robot assembly
103, wherein the substrate transferring robot's components and a
substrate S are free to move without colliding with other cluster
tool components external to the substrate transferring robot. While
the clearance region 90A may be described as a volume, often the
most important aspect of the clearance region 90A is the horizontal
area (x and y-directions), or footprint, occupied by the clearance
region 90A, which directly affects a cluster tool's footprint and
COO. The footprint of clearance region 90A is illustrated in FIGS.
1K, 1L as the regions defined by the length L and width W.sub.1,
W.sub.2, respectively. In addition to smaller system footprint, a
smaller clearance region allows closer positioning between transfer
robot assembly 103 and locations that are accessed thereby, such as
buffer chambers 122A, 122B and staging platforms 123A, 123B,
reducing substrate transfer times and increasing throughput. The
configurations of transfer robot assembly 103 described herein have
particular advantage over a SCARA robot CR illustrated in FIG. 1L.
This is due to the way in which the transfer robot 86, as
illustrated in FIG. 1K, may retract its components to be oriented
along the major length L of clearance region 90A. A SCARA robot CR,
as illustrated in FIG. 1L, cannot.
[0070] FIGS. 1G, 1H, 1I and 1M illustrate one configuration of a
two bar linkage robot 305 that, when used as transfer robot 86, may
retract as shown in FIG. 1K. Referring to FIG. 1M, Two bar linkage
robot 305 generally contains a support plate 321, a first linkage
310, a robot blade 87, a transmission system 312, an enclosure 313
and a motor 320. In this configuration the two bar linkage robot
305, which is serving as transfer robot 86, is attached to the
vertical motion assembly 95 through the support plate 321 which is
attached to the vertical motion assembly 95 (shown in FIG. 1F).
FIG. 1M illustrates a cross-sectional side view of one
configuration of the two bar linkage robot 305 type of transfer
robot assembly 86. The transmission system 312 in the two bar
linkage robot 305 generally contains one or more power transmitting
elements that are adapted to cause the movement of the robot blade
87 by motion of the power transmitting elements, such as by the
rotation of motor 320. In general, the transmission system 312 may
contain gears, pulleys, etc. that are adapted to transfer
rotational or translation motion from one element to another. In
one aspect the transmission system 312, as shown in FIG. 1M,
contains a first pulley system 355 and a second pulley system 361.
The first pulley system 355 has a first pulley 358 that is attached
to the motor 320, a second pulley 356 attached to the first linkage
310, and a belt 359 that connects the first pulley 358 to the
second pulley 356, so that the motor 320 can drive the first
linkage 310. In one aspect, a plurality of bearings 356A are
adapted to allow the second pulley 356 to rotate about the axis
V.sub.1 of the third pulley 354.
[0071] The second pulley system 361 has a third pulley 354 that is
attached to support plate 321, a fourth pulley 352 that is attached
to the blade 87 and a belt 362 that connects the third pulley 354
to the fourth pulley 352 so that the rotation of the first linkage
310 causes the blade 87 to rotate about the bearing axis 353 (pivot
V.sub.2) coupled to the first linkage 310. When in transferring a
substrate the motor drives the first pulley 358 which causes the
second pulley 356 and first linkage 310 to rotate, which causes the
fourth pulley 352 to rotate due to the angular rotation of the
first linkage 310 and belt 362 about the stationary third pulley
354. In one embodiment, the motor 320 and system controller 111 are
adapted to form a closed-loop control system that allows the
angular position of the motor 320 and all the components attached
thereto to be controlled. In one aspect the motor 320 is a stepper
motor or DC servomotor.
[0072] A more detailed description of a cartesian robot that may be
contained in some configurations of the invention may be found in
commonly assigned U.S. patent application Ser. No. 11/398,218 filed
on Apr. 5, 2006, which is hereby incorporated by reference in its
entirety to the extent not inconsistent with the claimed
invention.
Process Fluid Delivery System
[0073] For ALD and CVD processing of substrates, there are
generally three methods that chemical precursors are treated to
form a process fluid that can be delivered to a process volume of a
processing chamber to deposit a layer of a desired material on a
substrate. The term process fluid, as used herein, is generally
meant to include a gas, vapor, or a liquid. The first treatment
method is a sublimation process in which the precursor, which is in
solid form in an ampoule, is vaporized using a controlled process,
allowing the precursor to change state from a solid to a gas or
vapor in the ampoule. The precursor-containing gas or vapor is then
delivered to the process volume of a processing chamber. The second
method used to generate a precursor-containing process gas is by an
evaporation process, in which a carrier gas is bubbled through a
temperature controlled liquid precursor, and thus is carried away
with the flowing carrier gas. A third process used to generate a
precursor is a liquid delivery system in which a liquid precursor
is delivered to a vaporizer by use of a pump, in which the liquid
precursor changes state from a liquid to a gas by the addition of
energy transferred from the vaporizer. The added energy is
typically in the form of heat added to the liquid. In any of the
three methods described above for creating a precursor-containing
process fluid, it is typically necessary to control the temperature
of the precursor ampoule as well as the fluid delivery lines
between the ampoule and the processing chamber. This is
particularly true of ALD processes, wherein temperature control of
said delivery lines is very important in achieving process
repeatability. Hence, when tight control of precursor temperature
is required, the distance between the precursor ampoule and the
processing chamber served thereby should be minimized to avoid
unnecessary system cost, complexity, and reliability.
[0074] FIG. 1N illustrates a schematic diagram of one configuration
of a precursor delivery system 501 that is used to deliver a
process fluid to the process volume of a processing chamber, such
as reactor 121A. In the example illustrated, precursor delivery
system 501 is a liquid delivery type process fluid source. The
components of precursor delivery system 501 may be contained
proximate each other in a facilities tower 130, which is
illustrated in FIG. 1A. Precursor delivery system 501 is fluidly
coupled to reactor 121A via inlet line 505, which may be contained
in an overhead rack 140. The routing of inlet line 505 to reactor
121A through overhead rack 140 enables positioning of precursor
delivery system 501 proximate reactors 121A without impeding
service access to batch processing stations 101A, 101B. Ordinarily,
precursor delivery system 501 is located significantly further from
reactor 121A, for example in a different room or even a different
floor. Referring back to FIG. 1N, precursor delivery system 501, in
this configuration, generally includes the following components: an
ampoule gas source 512, an ampoule 139 containing a precursor "A",
a metering pump 525, a vaporizer 530, an isolation valve 535, a
collection vessel assembly 540 and a final valve 503. The
collection vessel assembly 540 generally includes the following
components: an inlet 546, an outlet 548, a vessel 543, a resistive
heating element 541 surrounding the vessel 543, a heater controller
542 and a sensor 544. In one configuration, the heater controller
542 is part of the system controller 111.
[0075] Precursor delivery system 501 is adapted to deliver a
process gas to the process volume 127 of reactor 121A from the
ampoule 139 containing a liquid precursor. To form a gas from a
liquid precursor, the liquid precursor is vaporized by use of a
metering pump 525 which pumps the precursor into the vaporizer 530,
which adds energy to the liquid, causing it to change state from a
liquid to a gas. Metering pump 525 is adapted to control and
deliver the liquid precursor at a desired flow rate set point
throughout the process recipe step, by use of commands from the
system controller 111. The vaporized precursor is then delivered to
the collection vessel assembly 540 where it is stored until it is
injected into the process volume 127 and across the surface of the
substrates W.
[0076] The inlet line 505 is heated to assure that an injected
precursor does not condense and remain on the surface of inlet line
505, which can generate particles and affect the chamber process.
It is also common to control the temperature of the inlet line 505
and other components of precursor delivery system 501 below the
precursor decomposition temperature to prevent gas phase
decomposition and/or surface decomposition of the precursor
thereon. Hence, reliable temperature control of numerous components
of precursor delivery system 501, including inlet line 505, is
important to CVD and particularly ALD processes. The temperature
control should reliably maintain the necessary components of
precursor delivery system 501 within a well-defined temperature
window to avoid serious process problems.
[0077] Because reliable and accurate temperature control of inlet
line 505 are made much more problematic and expensive for a longer
inlet line 505, inlet line 505 may be minimized by positioning
precursor delivery system 501 as close as possible to the reactors
serviced thereby. Referring to FIG. 1A, precursor delivery system
501 may be located in facilities tower 130, which is proximate
reactors 121A, 121B. To that end, facilities tower 130 is
positioned as close as possible to reactors 121A, 121B while still
maintaining a service distance 137 that is adequate to accommodate
service of facilities tower 130 and other components of system 100,
such as batch processing station 101B and transfer robot assembly
103 via access door 135A. Service distance 137 may be a SEMI
(Semiconductor Equipment and Materials International) compliant
service distance, usually on the order of 36 inches. Alternatively,
precursor delivery system 501 may be positioned in cabinets 146A,
146B proximate batch processing stations 101A, 101B, respectively,
as shown in FIG. 1B. In another configuration, precursor delivery
system 501 may be positioned on top of system 100 in cabinets 145,
as illustrated in FIG. 1O.
FOUP Stocker
[0078] Unlike single-substrate processing systems, a batch
processing system, such as system 100, typically processes
substrates from multiple FOUP's simultaneously. For example, a
standard FOUP contains up to 25 substrates whereas a batch of
substrates processed by system 100 may be as large as 50 or 100
substrates. Considering that system 100 may include two or more
batch processing stations, as many as 100 to 200 substrates may be
undergoing processing at any one time in system 100, the equivalent
of up to 12 or more FOUP's. In order to minimize the footprint of
system 100, however, FI 102 typically only includes two or three
load stations 104A-C, as illustrated in FIG. 1A. Empty FOUP's
waiting for processed substrates must therefore be removed from the
load stations 104A-C to allow loading and unloading of substrates
from other FOUP's. In addition, each FOUP must be correctly staged
to load stations 104A-C after processing so that the correct
substrates are loaded therein. Further, FOUP's must be received
from and returned to the central FOUP transport system of the
fabrication plant, such as an overhead monorail FOUP transport
system. Hence, managing a large number of FOUP's during processing
without slowing throughput or unreasonably expanding the footprint
of system 100 is a non-trivial consideration.
[0079] To that end, system 100 may be configured with a FOUP
stocker 150 (shown in FIG. 1B) positioned proximate load stations
104A-C. The FOUP stocker may include one or more storage shelves
and FOUP transfer mechanisms that may include a shelf capable of
raising or lowering a FOUP between the FOUP storage locations and
load stations 104A-C of system 100. In one configuration, the
storage shelves are themselves adapted to raise and lower a FOUP
therebetween. In another configuration, a FOUP handler or other
FOUP transfer device may be adapted to transfer a FOUP between the
FOUP storage locations and load stations 104A-C. The FOUP stocker
may be positioned in front of or beside the fabrication tool, but
to avoid increasing the footprint of system 100, the FOUP stocker
is preferably positioned over load stations 104A-C.
[0080] FIG. 1P is a side view of a stocker apparatus, stocker 150,
adapted for the management of sealed substrate transport pods, such
as FOUP's, during the processing by a batch processing platform,
such as system 100. The stocker 150 includes first and second
vertical transfer mechanisms, i.e., a first robot 713 and a second
robot 715, respectively. The first robot 713 includes a first
y-axis component 717 and a first x-axis component 719 movably
coupled to the first y-axis component 717 such that the first
x-axis component 719 may travel along the length of the first
y-axis component 717. Similarly, the second robot 715 includes a
second y-axis component 721 and a second x-axis component 723
movably coupled to the second y-axis component 721 such that the
second x-axis component 723 may travel along the length of the
second y-axis component 721. Operatively coupled between the first
robot 713 and the second robot 715 are one or more storage
locations 725a, 725b.
[0081] The first robot 713 is configured such that when the first
x-axis component 719 is at the lower portion of the first y-axis
component 717 it may access the one or more load stations 104A-B
and position a FOUP thereon. The first robot 713 is further
configured such that when the first x-axis component 719 is at the
upper portion of the first y-axis component 717 it may access an
overhead wafer carrier transport system such as a monorail,
referenced generally by the numeral 729a. The second robot 715 is
configured such that when the second x-axis component 723 is at the
lower portion of the second y-axis component 721 it may also access
the one or more load stations 104A-B and position a FOUP thereon.
Both the first x-axis component 719 and the second x-axis component
23 are configured so as to reach any of the storage locations 725a,
725b. In a preferred configuration, first robot 713 is adapted with
a plurality of first y-axis components 717 in lieu of storage
locations 725a, 725b. In this preferred configuration, second robot
715 is similarly configured.
[0082] FIG. 1Q is a front elevation view of the stocker 150 of FIG.
1P which shows a preferred arrangement of four storage locations
725a, 725b, 725c, and 725d, above load stations 104A, 104B. FOUP's
751, 753, 755, and 757 are in storage on the storage locations
725a, 725b, 725c and 725d, respectively. The FOUP capacity of the
stocker 150 may be increased with additional storage locations
added above and/or adjacent storage locations 725a, 725b, 725c and
725d. Additional storage locations positioned adjacent storage
locations 725a, 725b, 725c and 725d may require one or more
additional robots similar to first robot 713 and second robot 715,
each configured with an x-axis component and a y-axis
component.
Multiple Arm Robot Platform--Zero Side Access Configuration
[0083] In one aspect of the invention, the multiple arm robot
platform includes two batch processing chambers configured with a
service aisle disposed therebetween to provide necessary service
access to the transfer robot and the deposition stations. Required
service areas are generally included as part of the footprint in
the COO calculation for a substrate processing system, often making
up a substantial fraction of the overall footprint of the system.
Further, if required access areas are not only reduced but are
eliminated on both sides of a processing system, one processing
system may be situated abutting other systems, maximizing efficient
use of floor space. Therefore, incorporation of all required
service areas into other regions of a substrate processing system
in a manner that eliminates the need for side access can
substantially reduce the effective footprint thereof.
[0084] FIG. 2A is a schematic plan view of one aspect of the
invention, a batch processing platform, hereinafter referred to as
system 200, wherein no side access is required in order to service
all components thereof. FIG. 2B is a schematic side view of system
200. FIG. 2C is a perspective view thereof.
[0085] System 200 generally includes two or more batch processing
stations 201A, 201B, a system controller 111, a factory interface
(FI) 102, containing a transfer robot 220 and one or more load
stations 104A, 104B, and a process fluid delivery system. The fluid
delivery system may be contained in facilities towers 130A, 130B
and is organized substantially the same as the process fluid
delivery system for system 100, described above in conjunction with
FIG. 1N. As with system 100, a FOUP stocker (not shown) may be
positioned over load stations 104A, 104B to provide local storage
of FOUP's or other substrate transport pods during batch processing
of substrates.
[0086] The batch processing stations 201A, 201B are disposed
adjacent FI 102 and are separated from each other by a common
access space 250, which is adapted to provide service access to
batch processing stations 201A, 201 B and to transfer robot 220.
The presence of common access space 250 obviates the need for side
access areas along sides 251, 252 of system 200, allowing system
200 to be positioned directly in contact with a wall or other
processing system along sides 251, 252.
[0087] Referring to FIGS. 2A-D, batch processing station 201A
includes a reactor 221A, a buffer chamber 222A positioned adjacent
reactor 221A, and a staging platform 223A positioned in FI 102 and
adapted to support a staging cassette (not shown) proximate reactor
221A. Similarly, batch processing station 201B includes a reactor
221B, a buffer chamber 222B, and a staging platform 223B positioned
in FI 102 and adapted to support a staging cassette (not shown)
proximate reactor 221B. Batch processing stations 201A, 201B, FI
102, and overhead tack 210 are generally organized the same as
their counterparts in system 100, batch processing stations 101A,
101B described above in conjunction with FIG. 1A.
[0088] One difference between the organization and operation of
system 200 from system 100 is the relative orientation of FI 102,
batch processing stations 201A, 201B, and the transfer robot. In
system 200, there is preferably one load station positioned
opposite each batch processing station. In the configuration
illustrated in FIG. 2A for example, load stations 104A, 104B are
positioned opposite batch processing stations 201A, 201B,
respectively. Another difference between system 100 and system 200
is the configuration of the transfer robot. In system 200, transfer
robot 220 is preferably not a cartesian robot, unlike transfer
robot assembly 103. Transfer robot 220 may be a conventional SCARA
robot mounted on a track 220T. Transfer robot 220 is adapted to
travel along track 220T to serve all batch processing stations
201A, 201B of system 200. Because less service access is required
for this configuration of robot, it may be serviced adequately from
common access space 250 or from front skin 253.
[0089] Other features of transfer robot 220 are substantially the
same as transfer robot assembly 103, including the use of a single
blade robot arm for transferring substrates from the a low density
FOUP to a higher density staging cassette and the use of a multiple
blade robot arm for transferring multiple substrates from a staging
FOUP to an equal density processing cassette.
[0090] In one configuration, a stationary transfer robot, i.e., not
track-mounted, is disposed between each batch processing station
201A, 201B and load station 104A, 104B, respectively. In this
configuration, each transfer robot serves a single batch processing
station. If batch processing stations 201A, 201B are each adapted
to perform a different process on groups of substrates
sequentially, stocker 150 enables the transfer of substrates
between batch processing stations 201A, 201B by moving FOUP's
between load stations 104A, 104B as required.
[0091] System 200 may include a dedicated facilities tower 130A,
130B for each batch processing station 201A, 201B, as illustrated
in FIGS. 2A and 2D, each containing a precursor delivery system
501. In this configuration, the use of facilities towers 130A, 130B
creates an access opening 130C between facilities towers 130A and
130B. In another configuration, facilities towers 130A, 130B may be
combined into a single facilities tower containing a precursor
delivery system 501 for each batch processing station 201A,
201B.
Cassette Handler Platform
[0092] In another embodiment of the invention, a cassette handler
transfers the processing cassette between a processing chamber and
a cooling station to minimize chamber idle time. A single arm robot
transfers individual substrates between a substrate transport pod
and a processing cassette. In one aspect, the cassette handler is a
linear translator adapted to transfer a processing cassette between
one or more processing chambers and a cooling station. In another
aspect, the cassette handler is a rotary table adapted to swap a
cassette of unprocessed substrates with a cassette of processed
substrates.
Linear Translator Configuration
[0093] FIG. 3A is a schematic plan view of one aspect of the
invention, a batch processing platform containing a linear
translator, hereinafter referred to as system 300. The linear
translator robot is adapted to transfer processing cassettes
between a staging platform, at least one batch processing chamber,
and a cassette loading station. FIG. 3B is a schematic side view of
system 300.
[0094] To maintain high throughput for a batch processing platform,
it is important to minimize reactor idle time. Contributing factors
to reactor idle time include long pump-down and vent times for the
reactor, substrate cooling time, and substrate transfer time. The
configuration illustrated in FIGS. 3A, 3B may reduce or eliminate
the contribution of each of these factors on system throughput.
[0095] System 300 includes one or more reactors 1301, 1302, a
cassette transfer region 1305, a factory interface (FI) 102, and a
process fluid delivery system. FI 102 contains one or more load
stations 104A-C, a cassette loading station 1303, an environmental
control assembly 110, and a loading robot 1304 adapted to transfer
substrates between the load stations 104A-C and a processing
cassette positioned on cassette loading station 1303. Cassette
transfer region 1305 contains a staging platform 1306 and a linear
translator robot 1320, which is mounted to a horizontal rail 1321
and is adapted to transfer processing cassettes between the staging
platform 1306, the reactors 1301, 1302, and the cassette loading
station 1303. The process fluid delivery system may be contained in
facilities towers 130A, 130B and is organized substantially the
same as the process fluid delivery system for system 100, described
above in conjunction with FIG. 1N. As with system 100, a FOUP
stocker may be positioned over load stations 104A-C to provide
local storage of FOUP's or other substrate transport pods during
batch processing of substrates.
[0096] Components of system 300 that are substantially the same in
organization and operation as the corresponding components of
system 200 include FI 102, transfer robot 1304, reactors 1301,
1302, facilities towers 130A, 130B, and the process fluid delivery
system.
[0097] In operation, a first processing cassette 1330 disposed in
FI 102 and positioned on cassette loading station 1303 is loaded
with substrates from one or more FOUP's positioned on load stations
104A-C by transfer robot 1304. In one configuration, transfer robot
1304 may be a single track-mounted robot similar to transfer robot
220, described above in conjunction with FIGS. 2A-C. First
processing cassette 1330 is then vertically translated to a
position adjacent load lock 1309 by a vertical lift mechanism
1303A, such as a vertical indexer or a motorized lift. Processing
cassette 1330 is then loaded into load lock 1309 and is pumped down
to a level of vacuum substantially equal to that present in
cassette transfer region 1305 and reactors 1301, 1302. Processing
cassette 1330 may also be pressure cycled prior to entry into
cassette transfer region 1305. After pump-down, vacuum-tight door
1312 opens and processing cassette 1330 is transferred from load
lock 309 into cassette transfer region 1305 by linear translator
robot 1320, which is adapted with a cassette lift mechanism. Linear
translator robot 1320 is adapted to translate a processing cassette
along horizontal path 1322, to transfer a processing cassette
vertically into and out of the one or more reactors 1301, 1302
along vertical paths 1323, and to transfer a processing cassette on
or off of staging platform 1306. First processing cassette 1330 is
then loaded into an idle reactor, such as reactor 1301 or 1302 by
linear translator robot 1320. After processing is complete, first
processing cassette 1330 is unloaded from reactor 1301 by linear
translator robot 1320 and transferred to staging cassette 1306 for
cooling. After the substrates are sufficiently cooled, first
processing cassette 1330 is transferred to load lock 1309 by linear
translator robot 1320, vented to atmospheric pressure, lowered into
FI 102 by vertical lift mechanism 1303A, and unloaded by transfer
robot 1304. Alternatively, first processing cassette may undergo
atmospheric cooling in load lock 1309 after being vented to
atmosphere. In this configuration, free or forced convective
cooling may be used.
[0098] In a preferred sequence, first processing cassette 1330 is
positioned in load lock 1309 with unprocessed substrates before
processing is completed on second processing cassette 1331 in
reactor 1301. In so doing, reactor 1301 is idle for a short time,
i.e., on the order of about 1 minute. Reactor idle time is no
longer than the time necessary for linear translator robot 1320 to
transfer second processing cassette 1331 to staging platform 1306
plus the time to transfer first processing cassette 1330 into
reactor 1301. Substrate loading and unloading as well as load lock
pumping and venting are carried out "off-line", i.e., while the
reactors are processing substrates. Hence, the reactors are not
idle while the time-consuming steps involved in transferring
substrates from load stations 104A-C to reactors 1301, 1302 take
place, maximizing system throughput. Preferably, reactors 1301,
1302 are staged, i.e., substrate processing is started alternately
in each, to ensure that reactor loading/unloading is not limited by
the availability of linear translator robot 1320.
[0099] In an alternate configuration, cassette transfer region 1305
is an atmospheric pressure transfer region, preferably purged with
low moisture, inert gas, such as dry nitrogen. In this
configuration, a processing cassette is loaded with substrates in
FI 102 and transferred directly to reactors 1301, 1302 without
passing through a vacuum load lock. In this configuration, vertical
lift mechanism 1303A and load lock 1309 are not needed.
[0100] In another alternate configuration, each of reactors 1301,
1302 of system 300 may be adapted to sequentially perform a
different batch process on the same group of substrates. In this
configuration, the preferred processing sequence includes
processing first processing cassette 1330 in reactor 1301 with the
first batch process, transferring first processing cassette 1330 to
reactor 1302 with linear translator robot 1320 for processing with
a second batch process. First processing cassette 1330 is then
transferred to staging platform 1306 for cooling and subsequent
removal from systems 300 as described above.
Rotational Cross Configuration
[0101] FIG. 4A is a schematic plan view of one aspect of the
invention, a batch processing platform, hereinafter referred to as
system 400, wherein a rotational cross robot is adapted to
rotatably swap two pairs of processing cassettes between two
reactors and two vacuum load locks. FIG. 4B is a schematic side
view of system 400.
[0102] As noted above, system throughput is substantially improved
by performing the most time-consuming elements of substrate
transfer while the reactors are processing substrates, such as
substrate loading and unloading and load lock pumping and venting.
The configuration illustrated in FIGS. 4A and 4B may reduce or
eliminate the contribution of these factors on system
throughput.
[0103] System 400 includes two reactors 401, 402, two vacuum load
locks 403, 404, an evacuated cassette transfer region 406
positioned beneath the vacuum load locks 403, 404 and the reactors
401, 402, a factory interface (FI) 102, and a process fluid
delivery system. Load locks 403, 404 may serve as cool-down
stations for cassettes containing processed substrates and may
further serve as loading stations for transferring substrates
between processing cassettes disposed therein and load stations
104A-C. FI 102 contains one or more load stations 104A-C, an
environmental control assembly 110, and a transfer robot 405
adapted to transfer substrates between the load stations 104A-C and
the vacuum load locks 403, 404. Transfer robot 405 is substantially
the same single track-mounted robot as transfer robot 220,
described above in conjunction with FIGS. 2A-D, but with an
extended z-motion capability. System 400 also includes a rotational
cross robot 407 is positioned in evacuated cassette transfer region
406. Rotational cross robot 407 is adapted to position cassettes in
and remove cassettes from reactors 401, 402 and vacuum load locks
403, 404 by vertical motion along vertical path 407A. Rotational
cross robot 407 is further adapted to rotatably swap two processing
cassettes containing processed substrates with two processing
cassettes containing unprocessed substrates.
[0104] Components of system 400 that are substantially the same in
organization and operation as the corresponding components of
system 200 include FI 102, transfer robot 405, reactors 401,402,
facilities towers 130A, 130B, overhead rack 140, and the process
fluid delivery system. As with system 100, a FOUP stocker may be
positioned over load stations 104A-C to provide local storage of
FOUP's or other substrate transport pods during batch processing of
substrates.
[0105] In operation, processing cassettes located in loadlocks 403,
404 are loaded with substrates from load stations 104A-C with
transfer robot 405. Vacuum-tight door 156 closes and loadlocks 403,
404 are evacuated to the same level of vacuum present in evacuated
transfer region 406. Gate valve 420 opens and the processing
cassettes are lowered into evacuated transfer region 406 by
rotational cross robot 407. Rotational cross robot 407 then rotates
180.degree., positioning the processing cassettes under reactors
401, 402. Gate valve 421 opens and rotational cross robot 407 loads
the processing cassettes into reactors 401, 402, gate valve 421
closes, and ALD or CVD processing may be performed on the
substrates contained in the processing cassettes. After processing
in reactors 401, 402 is complete, rotational cross robot 407
returns the processing cassettes to load locks 403, 404 by a
similar process of lowering, rotating, and lifting. Load locks 403,
404 are vented to atmospheric pressure and, once sufficiently
cooled, are transferred to one or more FOUP's positioned on load
stations 104A-C.
[0106] In a preferred sequence, two processing cassettes are
processed in reactors 401, 402 at the same time that two processing
cassettes in load locks 403, 404 are being loaded with unprocessed
substrates. In this way, cassettes containing unprocessed
substrates are loaded and pumped down while the reactors are
processing two other cassettes. In addition, cassettes containing
freshly processed substrates are vented to atmosphere, cooled, and
unloaded while the reactors are processing other cassettes. Hence,
reactor idle time is reduced to a few seconds, i.e., the time
necessary for the rotational cross robot 407 to lower, rotate and
raise the processing cassettes.
Atmospheric Rotary Table Configuration
[0107] FIG. 5 is a schematic plan view of one aspect of the
invention, a batch processing platform, hereinafter referred to as
system 500, wherein a rotary table with a linear horizontal motion
transfers processing cassettes between two staging platforms and
two batch processing stations.
[0108] An important component of the COO of a substrate processing
platform is downtime related to planned and unplanned maintenance.
Hence, a processing platform may have a relatively high nominal
throughput, i.e., substrates processed per hour, but if it suffers
from substantially higher downtime compared to other systems, it
may effectively have a long-term throughput, i.e., substrates
processed per month, that is much lower than other systems. To that
end, having fewer robots that perform less complex motions is a
beneficial feature of a processing platform. The configuration
illustrated in FIG. 5 has this feature.
[0109] System 500 includes two batch processing stations, 501A,
501B, an atmospheric transfer region 502, two staging platforms
503A, 503B, a single transfer robot 504, a processing fluid
delivery system, and a rotary table 505A adapted to transfer
processing cassettes rotationally and with a linear horizontal
motion. The atmospheric transfer region 502 is similar in
organization and operation to FI 102, described above in
conjunction with FIG. 1C, and contains transfer robot 504, one or
more load stations 104A-B, and an environmental control assembly
(not shown for clarity). Batch processing stations, 501A, 501B are
similar in organization and operation to batch processing stations
101A, 101B, described above in conjunction with FIGS. 1A, 1B. An
important difference is that staging platforms 503A, 503B are not
positioned adjacent batch processing stations 501A, 501B,
respectively. In stead, processing cassettes are transferred
between staging platforms 503A, 503B and the buffer chambers
contained in batch processing stations 501A, 501B. The processing
cassettes are loaded horizontally into buffer chamber via a
horizontal motion radially by rotary table 505A. Transfer robot 504
is substantially the same single track-mounted robot as transfer
robot 220, described above in conjunction with FIGS. 2A-D. Transfer
robot 504 may be stationary, however, reducing the cost and
complexity of transfer robot 504 as well as improving the
reliability thereof. Due to the difference in substrate between a
typical FOUP and a processing cassette, transfer robot is
preferably equipped with only single blade robot arms, which
further reduces the complexity and cost of transfer robot 504.
[0110] Other components of system 500 that are substantially the
same in organization and operation as the corresponding components
of systems 200 include facilities towers 130A, 130B, overhead rack
140, and the process fluid delivery system. As with systems 100,
200, a FOUP stocker may be positioned over load stations 104AB to
provide local storage of FOUP's or other substrate transport pods
during batch processing of substrates.
[0111] In operation, processing cassettes located on staging
platforms 503A, 503B may be loaded with unprocessed substrates by
transfer robot 504. Staging platforms 503A, 503B may further serve
as cooling stations for freshly processed substrates. Rotary table
505A is adapted to remove a processing cassette loaded with
unprocessed substrates using a horizontal actuator and a small
Z-motion. Rotary table 505A then rotates as necessary to position
the processing cassette of unprocessed substrates adjacent an idle
batch processing station. After processing, rotary table 505A
returns cassettes to staging platforms 503A, 503B for cooling,
unloading, and reloading with unprocessed substrates.
[0112] In a preferred sequence, substrate cooling and
loading/unloading operations are performed while batch processing
stations 501A, 501B are processing substrates. A first processing
cassette is positioned on a staging platform, for example staging
platform 503A, and loaded with substrates while a batch processing
station, for example batch processing station 501A, is processing
substrates in a second processing cassette. Prior to the completion
of processing in batch processing station 501A, rotary table 505A
removes the first processing cassette from staging platform 503A.
Once processing is completed on the second processing cassette,
rotary table 505A removes the second processing cassette from batch
processing station 501A, rotates 180.degree., and places the first
processing cassette into batch processing station 501A. Rotary
table 505A then positions the second processing cassette on an
available staging platform 503A, 503B for cooling and subsequent
unloading. In this way, batch processing station 501A is only idle
for a matter of seconds, i.e. the time necessary for rotary table
505A to remove a cassette, rotate 180.degree., and position a
second cassette in a batch processing station. In addition, the
configuration illustrated in FIG. 5 has fewer and/or simpler robots
than other configurations of batch processing platform.
[0113] In one configuration, staging platforms 503A, 503B are
capable of sufficient vertical motion to accommodate the transfer
of substrates and/or processing cassettes thereon. This
configuration further simplifies the design of rotary table 505A,
increasing the reliability thereof.
[0114] 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, and
the scope thereof is determined by the claims that follow.
* * * * *