U.S. patent application number 10/193605 was filed with the patent office on 2002-11-21 for method and apparatus for improved substrate handling.
Invention is credited to Gantvarg, Eugene, Goder, Alexey, Grunes, Howard E., Perlov, Ilya.
Application Number | 20020170672 10/193605 |
Document ID | / |
Family ID | 46276720 |
Filed Date | 2002-11-21 |
United States Patent
Application |
20020170672 |
Kind Code |
A1 |
Perlov, Ilya ; et
al. |
November 21, 2002 |
Method and apparatus for improved substrate handling
Abstract
A method and apparatus are provided for substrate handling. In a
first aspect, a temperature adjustment plate is located below a
substrate carriage and is configured such that a substrate may be
transferred between the temperature adjustment plate and the
substrate carriage by lifting and lowering the substrate carriage
above and below the top surface of the temperature adjustment
plate. The temperature adjustment plate may be configured to heat
and/or cool a substrate positioned thereon. Numerous other aspects
are provided.
Inventors: |
Perlov, Ilya; (Santa Clara,
CA) ; Goder, Alexey; (Sunnyvale, CA) ;
Gantvarg, Eugene; (Santa Clara, CA) ; Grunes, Howard
E.; (Santa Cruz, CA) |
Correspondence
Address: |
APPLIED MATERIALS, INC.
PATENT COUNSEL
Legal Affairs Department
P.O.BOX 450A
Santa Clara
CA
95052
US
|
Family ID: |
46276720 |
Appl. No.: |
10/193605 |
Filed: |
July 11, 2002 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10193605 |
Jul 11, 2002 |
|
|
|
09538013 |
Mar 29, 2000 |
|
|
|
09538013 |
Mar 29, 2000 |
|
|
|
09332207 |
Jun 12, 1999 |
|
|
|
6287386 |
|
|
|
|
09332207 |
Jun 12, 1999 |
|
|
|
08869111 |
Jun 4, 1997 |
|
|
|
5951770 |
|
|
|
|
Current U.S.
Class: |
156/345.31 ;
118/719 |
Current CPC
Class: |
H01L 21/67766 20130101;
H01L 21/67196 20130101; H01L 21/68771 20130101; H01L 21/67126
20130101; H01L 21/68792 20130101; H01L 21/68785 20130101; H01L
21/67103 20130101; Y10S 414/139 20130101; H01L 21/67745 20130101;
Y10S 414/135 20130101; Y10S 414/137 20130101; H01L 21/67109
20130101; H01L 21/67742 20130101; H01L 21/68764 20130101 |
Class at
Publication: |
156/345.31 ;
118/719 |
International
Class: |
C23C 016/00; C23F
001/00 |
Claims
The invention claimed is:
1. A method of transferring a substrate to a vacuum processing
chamber comprising: placing a substrate within a transfer chamber;
adjusting the temperature of the substrate while the substrate is
within the transfer chamber; and transferring the substrate from
the transfer chamber to a vacuum processing chamber via a substrate
handler positioned within the transfer chamber.
2. The method of claim 1 wherein adjusting the temperature of the
substrate comprises placing the substrate on a temperature
adjustment plate.
3. The method of claim 1 further comprising storing at least a
first substrate and adjusting the temperature of the first
substrate while a second substrate is being processed within the
vacuum processing chamber.
4. A method of transferring a substrate to a vacuum processing
chamber comprising: placing a substrate within a transfer chamber;
employing a temperature adjustment plate to adjust the temperature
of the substrate while the substrate is within the transfer
chamber; and transferring the substrate from the transfer chamber
to a vacuum processing chamber via a substrate handler positioned
within the transfer chamber.
5. The method of claim 4 wherein adjusting the temperature of the
substrate comprises placing the substrate on the temperature
adjustment plate.
6. The method of claim 4 further comprising storing at least a
first substrate and adjusting the temperature of the first
substrate while a second substrate is being processed within the
vacuum processing chamber.
7. A vacuum processing tool comprising: one or more vacuum
processing chambers; a sealable transfer chamber adapted to pump
and vent between vacuum and atmospheric pressure; a substrate
handler contained within the sealable transfer chamber; and a
controller, coupled to the sealable transfer chamber, programmed to
pump and vent the sealable transfer chamber between vacuum and
atmospheric pressure, each time a substrate is loaded into or out
of the processing tool.
8. The apparatus of claim 7 wherein the substrate handler is
magnetically coupled.
9. The apparatus of claim 7 wherein the sealable transfer chamber
comprises a rotatable substrate storage member that operates in a
plane above the substrate handler; and wherein the substrate
storage member and the substrate handler are adapted such that
relative motion therebetween transfers a substrate between the
substrate handler and the substrate storage member.
10. The apparatus of claim 9 wherein the substrate handler
comprises a blade for supporting a substrate; and the substrate
storage member comprises a plurality of opposed substrate supports
which define a passage through which the substrate handler blade
may pass.
11. The apparatus of claim 9 wherein the substrate storage member
and the substrate handler are both supported by a first wall of the
sealable transfer chamber such that the substrate storage member
and the substrate handler both move if the first wall deflects.
12. The apparatus of claim 11 further comprising a temperature
adjustment plate adapted to support a substrate thereon; wherein
the substrate storage member and the temperature adjustment plate
are adapted such that relative motion therebetween transfers a
substrate between the substrate storage member and the temperature
adjustment plate, and wherein the temperature adjustment plate is
supported by the first wall of the sealable transfer chamber.
13. A method comprising: placing a substrate within a load
lock/transfer chamber; pumping the load lock/transfer chamber to a
desired vacuum level; opening a sealable slit that connects the
load lock/transfer chamber to a vacuum processing chamber;
transferring the substrate through the sealable slit into the
vacuum processing chamber via a substrate handler contained within
the load lock/transfer chamber.
14. The method of claim 13 wherein transferring the substrate
comprises transferring the substrate along a straight line from the
load lock/transfer chamber to the processing chamber.
15. The method of claim 13 wherein placing a substrate within the
load lock/transfer chamber comprises placing two substrates within
the load lock/transfer chamber; and further comprising storing one
of the two substrates within the load lock/transfer chamber while
processing the other within the vacuum processing chamber.
16. The method of claim 15 wherein placing the two substrates
within the load lock/transfer chamber comprises placing the two
substrates on a rotatable substrate carriage having two
horizontally adjacent storage locations; and further comprising
transferring a substrate to the substrate handler via positioning a
storage location above the substrate handler, and changing the
elevation of the substrate carriage relative to the substrate
handler.
17. The method of claim 16 wherein transferring the substrate into
the vacuum processing chamber comprises transferring the substrate
along a straight line from the load lock/transfer chamber to the
vacuum processing chamber.
18. A transfer chamber comprising: a sealable chamber having a main
portion and a smaller outwardly extending portion; a rotatable
substrate carriage contained within the sealable chamber, the
rotatable substrate support having: at least one substrate storage
location positioned within the main portion of the sealable
chamber; an internal magnet supporting portion that extends from a
central region of the rotatable substrate carriage into the
outwardly extending portion of the sealable chamber; at least one
internal magnet attached to the internal magnet supporting portion
that is contained in the outwardly extending portion of the
sealable chamber; at least one external magnet positioned outside
the outwardly extending portion of the sealable chamber and
magnetically coupled to the at least one internal magnet; and a
motor coupled to the at least one external magnet and adapted to
rotate the external magnet about the outwardly extending portion of
the sealable chamber so as to cause the rotatable substrate support
to rotate.
19. The apparatus of claim 18 wherein the motor is further adapted
to lift and lower the external magnet so as to cause the rotatable
substrate support to lift and lower.
Description
[0001] This application is a division of U.S. patent application
Ser. No. 09/538,013, filed Mar. 29, 2000, which is a
continuation-in-part of U.S. patent application Ser. No.
09/332,207, filed Jun. 12, 1999 (now U.S. Pat. No. 6,287,386) which
is a continuation of U.S. patent application Ser. No. 08/869,111,
filed Jun. 4, 1997 (now U.S. Pat. No. 5,951,770), all of which are
hereby incorporated by reference herein in their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to substrate processing, and
more particularly to a method and apparatus for improved substrate
handling.
BACKGROUND OF THE INVENTION
[0003] Cluster tools are commonly used in the fabrication of
integrated circuits. A cluster tool typically includes a load lock
chamber for introducing substrates (e.g., semiconductor wafers)
into the tool and a central transfer chamber for moving substrates
between the load lock chamber and a plurality of processing
chambers and one or more cool down chambers mounted on the transfer
chamber. Typically, either a single blade or a double blade robot
is located within the transfer chamber to move substrates between
the load lock chamber, the processing chambers, the cool down
chamber(s) and then back to the load lock chamber. Exemplary
cluster tools, robots and substrate handling methods are described
in U.S. Pat. Nos. 4,951,601 and 5,292,393, both of which are
incorporated herein by reference in their entirety.
[0004] Within a cluster tool a typical substrate handler arm
capable of 360.degree. rotation and extension is positioned inside
the central transfer chamber. In operation the substrate handler
rotates to align its blade with a sealable slit (e.g., a slit
valve) which connects the central transfer chamber to a load lock
chamber (i.e., a load lock slit). The substrate handler extends
through the load lock slit, picks up a substrate, retracts, rotates
to position the substrate in front of a processing chamber slit
(which connects the central transfer chamber with the processing
chamber) and extends through the slit to place the substrate in the
processing chamber. After the processing chamber finishes
processing the substrate, the wafer handler extends through the
processing chamber slit, picks up the substrate, retracts and
rotates to position the substrate in front of a cool down chamber
slit. The substrate handler again extends placing the substrate in
the cool down chamber and then retracts therefrom. After substrate
cooling is complete, the substrate handler extends through the cool
down chamber slit, picks up the substrate and retracts through the
cool down chamber slit in order to extract the substrate and carry
the substrate to another processing chamber or return the substrate
to the load lock chamber. While the substrate is processing or
cooling, the substrate handler places and extracts other substrates
from the remaining chambers (e.g., load lock, processing or cool
down chambers) in the same manner. Thus, the substrate handler
undergoes a complex pattern of rotations and extensions, requiring
a mechanically complex and expensive substrate handler. Further,
each substrate handler extension and rotation requires considerable
operating space and may introduce reliability problems.
[0005] One way to improve system efficiency is to provide a robot
arm having the ability to handle two substrates at the same time.
Thus, some equipment manufacturers have provided a robot arm in
which two carrier blades are rotated about a pivot point at the
robot wrist (e.g., via a motor and belt drive positioned at the
substrate handler's wrist). Thus, a first substrate (e.g., to be
processed) may be stored on one blade while the other blade picks
up a second substrate (e.g., previously processed). The carrier
blades are then rotated and the first stored substrate is placed as
desired. Such a mechanism is rather complex and requires a massive
arm assembly to support the weight of a carrier blade drive located
at the end of an extendible robot arm. For example, three drives
are usually required for a system incorporating such a robot arm:
one drive to rotate the arm, one drive to extend the arm, and one
drive to rotate the carrier blades. Any improvement in throughput
provided by such a multiple carrier robot comes at a price of
increased equipment/manufacturing cost, increased weight and power
consumption, and increased complexity and, thus, reduced
reliability and serviceability.
[0006] Another approach places two robot arms coaxially about a
common pivot point. Each such robot arm operates independently of
the other and improved throughput can be obtained through the
increased handling capacity of the system. However, it is not
simple to provide two robot arms for independent operation about a
common axis. Thus, multiple drives must be provided, again
increasing manufacture/equipment costs and complexity while
reducing reliability.
[0007] The various processes which are performed on the various
substrates, may require different processing times. Therefore, some
substrates may remain in a chamber for a short period of time after
processing is completed before they are moved into a subsequent
processing chamber because the subsequent processing chamber is
still processing another substrate. This causes a substrate back
log and decreases system throughput.
[0008] In addition to varying processing times, another factor
which affects throughput is the need to cool individual substrates
following processing. Specifically, the number of movements a
substrate handler must make in order to process numerous substrates
increases significantly when the substrates must be transferred to
one or more cool down chambers following each processing step.
Additionally, incorporation of one or more cool down chambers
reduces the number of positions on the transfer chamber where a
processing chamber may be positioned. Fewer processing chambers can
result in lower system throughput and can increase the cost of each
wafer processed.
[0009] Therefore, there remains a need for a method and apparatus
for improved substrate handling module which can increase substrate
throughput while preferably providing substrate cooling.
SUMMARY OF THE INVENTION
[0010] Embodiments of the present invention improve upon the
"Carousel Wafer Transfer System" described in U.S. Pat. No.
6,287,386 from which this application is a continuation-in-part.
Various embodiments of the invention provide aspects which enhance
substrate heating and cooling efficiency, reduce substrate handler
complexity, reduce contact between moving parts during substrate
transfer operation (e.g., reducing particle generation associated
therewith), improve substrate handling equipment reliability,
and/or increase substrate throughput.
[0011] In a first aspect, the invention comprises a temperature
adjustment plate located below a substrate carriage (such as the
rotatable carousel described in U.S. Pat. No. 6,287,386) and
configured such that a substrate may be transferred between the
temperature adjustment plate and the substrate carriage, by lifting
and lowering the substrate carriage above and below the top surface
of the temperature adjustment plate. The temperature adjustment
plate may be configured to heat and/or cool a substrate positioned
thereon.
[0012] In a second aspect, the substrate carriage is magnetically
coupled so as to rotate and/or lift and lower magnetically, thereby
reducing particle generation via contact between moving parts (and
potential chamber contamination therefrom).
[0013] In a third aspect, a substrate handler positioned below the
substrate carriage is both magnetically coupled and magnetically
levitated, providing further particle reduction. The magnetic
levitation is preferably achieved via four radially disposed and
vertically arranged magnet pairs having distance sensors for
maintaining desired spacing therebetween.
[0014] In a preferred embodiment, one substrate is heated/degassed
on a first portion of a temperature adjustment plate in preparation
for processing while a second substrate is processed, and a third
processed substrate is cooled on a second portion of the
temperature adjustment plate. An advantage of this arrangement is
that the chamber containing the substrate carriage requires only a
small volume of operating space, and may be quickly pumped to
vacuum pressure. Thus, certain embodiments need not employ a
separate load lock chamber.
[0015] Other features and advantages of the present invention will
become more fully apparent from the following detailed description
of the preferred embodiments, the appended claims and the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a top plan view of a chamber containing a
preferred substrate carriage and temperature adjustment plate;
[0017] FIG. 2A is a top plan view of the chamber of FIG. 1 showing
a substrate handler in an extended position;
[0018] FIG. 2B is a top plan view of the chamber of FIG. 1 showing
a substrate handler in a retracted position;
[0019] FIG. 3A is a side elevational view of a temperature
adjustment plate configured for heating;
[0020] FIG. 3B is a side elevational view of a temperature
adjustment plate configured for cooling;
[0021] FIG. 3C is a side elevational view of a temperature
adjustment plate configured for both heating and cooling;
[0022] FIG. 4A is a front elevational view showing a magnetically
coupled substrate carrier in an elevated position;
[0023] FIG. 4B is a front elevational view showing a magnetically
coupled substrate carrier in a lowered position;
[0024] FIG. 5A is a front elevational view of the chamber of FIG.
1, containing a preferred magnetically levitated and magnetically
coupled substrate handler; and
[0025] FIG. 5B is a side elevational view of the chamber of FIG. 1,
containing the preferred magnetically levitated and magnetically
coupled substrate handler of FIG. 5A.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] FIG. 1 is a top plan view of a chamber 11 containing a
preferred substrate carriage 13 and temperature adjustment plate
15. A central shaft 17 is fixedly coupled to the temperature
adjustment plate 15 and extends therefrom through a center region
of the substrate carriage 13. Preferably the central shaft 17 is
not in contact with the center region of the substrate carriage 13,
but rather is coupled to the substrate carriage 13 via a motor
(motor 57 in FIGS. 4A and 4B) as described further below with
reference to FIGS. 4A and 4B. The substrate carriage 13 comprises
three equally spaced branches 19a-c which extend radially outward
from the center region of the substrate carriage 13. Each branch
19a-c comprises a pair of substrate supports 21a-b which face
outwardly (i.e., away from each other) therefrom. The branches
19a-c are preferably machined from the same piece of material or
may be made of two or more separate parts connected together using
bolts, screws or other connectors including welding, such that they
rotate and/or elevate together as a unit. The branches 19a-c and
the substrate supports 21a (e.g., of a first branch 19a) and 21b
(e.g., of a second branch 19b) are configured so as to define a
plurality of substrate seats 23a-c each of which supports a
substrate (not shown) by its edge. By placing a substrate (not
shown) on a pair of substrate supports 21a-b secured to adjacent
branches (e.g., branches 19a, 19b, branches 19a, 19c or branches
19b, 19c) a passage is maintained for a substrate handler blade 24a
of a substrate handler 24 (shown in FIGS. 2A and 2B) to pass
therethrough during substrate handoffs between the substrate
carriage 13 and the substrate handler blade 24a, as described
further below.
[0027] The substrate supports 21a-b are preferably made of a
ceramic such as alumina, quartz or any other hard material which is
compatible with semiconductor substrates and does not produce
particles or scratch a substrate during contact therewith. The
substrate supports 21a-b are attached to the bottom of the branches
19a-c, such that the substrate carriage 13 may lower the substrate
supports 21a-b below the top surface of the temperature adjustment
plate 15, and below the substrate handler blade 24a, thus
transferring a substrate supported by a substrate seat 23a-c to the
temperature adjustment plate 15 and/or to the substrate handler
blade 24a, while the remainder of the substrate carriage 13 (i.e.,
the branches 19a-c) remains above and does not contact either the
temperature adjustment plate 15 and/or the substrate handler blade
24a. A preferred mechanism for lifting and lowering the substrate
supports 21a-b (and the substrate carriage 13) is described below
with reference to FIGS. 4A and 4B.
[0028] The temperature adjustment plate 15 is configured to
simultaneously support two substrates (not shown), when the
substrate carriage 13 lowers the substrate supports 21a-b to an
elevation below the top surface of the temperature adjustment plate
15. In order to achieve uniform heating or cooling across the
entire substrate surface, the temperature adjustment plate 15 is
preferably coextensive with the substrates placed thereon. Thus, in
order to allow the substrate supports 21a-b to lower to an
elevation below that of the top surface of the temperature
adjustment plate 15, the temperature adjustment plate 15 comprises
four notches 25a-d placed to receive the substrate supports 21a-b.
Preferably the temperature adjustment plate 15 also comprises a cut
out region 26 in which the substrate handler 24 (FIGS. 2A and 2B)
may be housed. As best understood with reference to FIGS. 2A and
2B, the cut out region 26 is configured to provide sufficient space
for the substrate handler 24 to extend and retract.
[0029] Preferably the chamber 11 has two sealable slits 27a-b
(e.g., conventional slit valves) positioned on opposite walls of
the chamber 11. Preferably the first slit 27a is disposed to
receive substrates from a substrate handler (not shown) which
travels among a plurality of transfer chambers (not shown)
configured such as transfer chamber 11, and the second slit 27b is
coupled to a processing chamber 29, as described in detail in
co-pending U.S. Provisional Patent Application Serial No.
60/187,133, filed Mar. 6, 2000 (AMAT No. 4026), the entire
disclosure of which is incorporated herein by this reference. The
processing chamber 29 is coupled to the slit 27b opposite the
substrate handler 24, such that the substrate handler blade 24a
travels in a straight line (e.g., along a single axis) to place and
extract substrates within and from the processing chamber 29, as
further described with reference to FIGS. 2A and 2B.
[0030] FIG. 2A is a top plan view of the chamber 11 of FIG. 1,
showing the substrate handler 24 in an extended position, and FIG.
2B is a top plan view of the chamber 11 of FIG. 1 showing the
substrate handler 24 in a retracted position. The exemplary
substrate handler 24 of FIGS. 2A-B may be analogized to a human arm
having an elbow 24b which extends outwardly when the arm retracts.
Such extendable arm type substrate handlers are conventionally
employed in semiconductor fabrication and their specific
configuration is well known in the art. Accordingly the notch 26
located in the temperature adjustment plate 15 is sized and shaped
to accommodate the substrate handler 24's elbow 24b during
substrate handler retraction, as shown in FIG. 2B. The substrate
handler 24 preferably includes a wafer gripping mechanism (not
shown) as described in U.S. Pat. No. 6,287,386 which stabilizes and
centers a substrate supported by the blade 24a.
[0031] FIG. 3A is a side elevational view of a temperature
adjustment plate 15a configured for heating (i.e., a heat plate
15a) that may be employed as the temperature adjustment plate 15.
The heating plate 15a has a resistive heating element 31 disposed
therein. The heating plate 15a may comprise any conventional heated
substrate support (e.g., a stainless steel substrate support)
having a temperature range sufficient for the heating process to be
performed (typically about 150-600.degree. C. for most annealing
applications). A substrate (e.g., a semiconductor wafer) may be
placed directly on the heating plate 15a (e.g., via the substrate
carriage 13); or optionally, on a plurality of pins 32 (preferably
3-6 pins, most preferably three pins 32a-c per substrate as shown
in FIGS. 2A and 2B) which extend from the heating plate 15a, so as
to facilitate gas flow along the backside of the substrate and so
as to reduce contact between the substrate and the heating plate
15a (thereby reducing particle generation by such contact). The
heating plate 15a of FIG. 3A includes two sets of pins 32a-c for
supporting two substrates. Short pin heights facilitate heat
transfer from the heating plate 15a to a substrate (not shown)
positioned thereon; preferably the pins 32a-c are between
0.005-0.02 inches in height.
[0032] To improve substrate temperature uniformity during heating,
the heating plate 15a preferably is larger than the diameter of the
substrate being heated (e.g., such that the heating plate extends
about an inch beyond the diameter of each substrate positioned
thereon). The heating plate 15a heats a substrate primarily by
conduction (e.g., either direct contact conduction if a substrate
touches the heating plate 15a or conduction through a dry gas such
as nitrogen disposed between the heating plate 15a and a substrate
when the substrate rests on the pins 32a-c). A convective heating
component also may be employed if gas is flowed along the backside
of the substrate during heating. However, the heating plate 15a may
require an elevated edge (not shown) or an electrostatic chuck (as
is known in the art) so as to prevent substrate movement due to
such backside gas flow.
[0033] The chamber 11 preferably has a small volume to allow for
rapid evacuation of the chamber (described below) and to reduce
process gas consumption. As shown in FIG. 1, a gas inlet 33 couples
an inert dry gas source 35 (such as a noble gas or nitrogen,
preferably 100% N.sub.2 having fewer than a few parts per million
of O.sub.2therein, or 4% or less of H.sub.2 diluted in N.sub.2 and
having fewer than a few parts per million of O.sub.2 therein) to
the chamber 11. The gas emitted from the dry gas source 35 may be
further "dried" via a getter or cold trap (not shown) within the
gas inlet 33. A gas outlet 37 couples the chamber 11 to a vacuum
pump 39 which, in operation, pumps gas from the chamber 11. Thus
the chamber 11 can be periodically or continuously purged with
inert gas to remove particles and desorbed gasses from the chamber
11.
[0034] The rate at which the inert gas flows into the chamber 11 is
controlled via a needle valve or flow controller 40 (e.g., a mass
flow controller) operatively coupled along the gas inlet 33.
Preferably, the vacuum pump 39 comprises a rough-pump, such as a
dry pump, having a pumping speed of between about 1-50 liters/sec
for rapid evacuation of the chamber 11. The gas outlet 37 comprises
an isolation valve 41, such as a pneumatic roughing port valve,
operatively coupled to the vacuum pump 39 so as to control the gas
flow rate from the chamber 11 and preferably further comprises a
chamber exhaust valve 43 for use during chamber purging. Because a
rough pump is capable of evacuating a chamber to a pressure of a
few milliTorr or higher, a rough pump alone may be employed for
applications wherein the chamber 11 is not evacuated below a
pressure of a few milliTorr (e.g., when the chamber 11 is vented to
atmospheric pressure with a non-oxidizing gas such as nitrogen
prior to loading a substrate therein or when a substrate is
transferred from the chamber 11 to a processing chamber 29 that
employs pressures of a few milliTorr or higher). However, for
applications that require pressures below a few milliTorr (e.g.,
pressures which cannot be obtained with a rough pump alone), a high
vacuum pump (not shown) such as a cryopump also may be employed to
allow substrate transfer between a high vacuum processing chamber
and the chamber 11 (e.g., in a chamber configured such as that
described in U.S. Pat. No. 6,287,386, which does not employ a
temperature adjustment plate 15, or in a chamber wherein the
temperature adjustment plate 15 is positioned so as to allow
substrate transfer to and from additional processing chambers).
[0035] To pre-condition the chamber 11 to a predetermined
contamination level (e.g., so that less than 10 parts per million
of O.sub.2 reside in the chamber 11) the chamber 11 may be purged
at atmospheric pressure by flowing dry gas from the dry gas source
35 into the chamber 11 with the chamber exhaust valve 43 open, may
be single-evacuation purged by evacuating the chamber 11 to a
predetermined vacuum level via the pump 39 (by opening the
isolation valve 41 coupled therebetween) and then back filling the
chamber 11 with dry gas from the dry gas source 35, or may be cycle
purged by repeatedly evacuating the chamber 11 to a predetermined
vacuum level and then back filling the chamber 11 with dry gas from
the dry gas source 35 to further reduce contamination levels beyond
those achievable by atmospheric pressure or single evacuation
purging.
[0036] FIG. 3B is a side elevational view of a temperature
adjustment plate 15b configured for substrate cooling (i.e., a
cooling plate 15b) that may be employed as the temperature
adjustment plate 15 for the chamber 11. Specifically, to affect
rapid cooling of a substrate following substrate heating within the
processing chamber 29 the substrate is placed on the cooling plate
15b via the substrate carriage 13, and water or a refrigerant
(e.g., a 50% de-ionized water, 50% glycol solution having a
freezing point below that of pure water) is flowed through channels
44 in the cooling plate 15b. For example, an aluminum cooling plate
may be cooled to about 5 to 25.degree. C. by a cooling fluid
supplied thereto from a cooling fluid source 45 via a pump 47.
[0037] The cooling plate 15b preferably also employs a diffuser
design as is known in the art, having up to ten thousand 0.02-0.1
inch diameter holes therein (not shown). The holes allow gas to
flow through the cooling plate 15b (e.g., from the dry gas source
35) and to be cooled by the cooling plate 15b so as to improve
cooling of a substrate positioned thereon (e.g., by cooling a
backside of the substrate). Like the heating plate 15a the cooling
plate 15b may require an elevated edge (not shown) or an
electrostatic chuck (as is known in the art) so as to prevent
substrate movement due to such backside gas flow. The walls of the
chamber 11 may be the water or refrigerant cooled as well to
further enhance substrate cooling.
[0038] FIG. 3C is a top plan view of a temperature adjustment plate
15c configured for both heating and cooling, where a first
substrate location (identified by reference numeral 15a') is
configured for substrate heating as described with reference to
FIG. 3A; and a second substrate location (identified by reference
numeral 15b') is configured for substrate cooling as described with
reference to FIG. 3B. The two substrate locations 15a', 15b' may be
part of an integral plate, or may comprise two physically separated
plates preferably with a distance of at least one inch
therebetween.
[0039] Regardless of the specific temperature adjustment plate
15a-c which the inventive chamber 11 employs, the inventive chamber
11 comprises relatively inexpensive components (e.g., the rotatable
substrate carriage 13 and the substrate handler 24 (preferably
adapted only for transferring a substrate along a straight line
(i.e., a linear substrate handler) such as between the chamber 11
and a processing chamber)). Heating and/or cooling is economically
performed with reduced footprint and increased throughput as the
need for substrate transfer time to a separate heating and/or
cooling module is eliminated. A controller C (FIG. 1) is coupled to
the various chamber components (e.g., to the temperature adjustment
plate 15, to the flow controller 40, to the isolation valve 41, to
the chamber exhaust valve 43, to the cooling fluid source 45, to
the heating element 31, to the substrate handler 24, to the motor
57, etc.) and is programmed so as to cause the inventive chamber 11
to perform the inventive method described below.
[0040] FIGS. 4A and 4B are front cross-sectional views of the
preferred substrate carriage 13 in an elevated position and in a
lowered position, respectively. As described below, the preferred
substrate carriage 13 employs magnetic coupling.
[0041] With reference to FIGS. 4A and 4B, the central shaft 17
extends upwardly through an aperture 47 in a top surface 11a of the
chamber 11. A first bellows 49 seals the aperture 47 to an
enclosure wall 50, positioned above the chamber 11. The enclosure
wall 50 encloses an internal magnet support 53 which is fixedly
coupled to, or integrally formed with the substrate carriage 13,
such that the internal magnet support 53 and the substrate carriage
13 move together as a unit.
[0042] As shown in FIGS. 4A and 4B, a plurality of internal magnets
51a-n (only internal magnets 51a and 51b are shown) are coupled to
the internal magnet support 53 and are spaced from and are
magnetically coupled to a plurality of external magnets 55a-n (only
external magnets 55a and 55b are shown). The internal and external
magnets 51a-n, 55a-n preferably are permanent magnets having a
number and spacing sufficient to allow the internal magnets 51a-n
(and the substrate carriage 13 coupled thereto) to rotate when the
external magnets 55a-n are rotated, and to elevate (i.e., lift or
lower) when the external magnets 55a-n are elevated. Preferably
there are four internal magnets 51a-n and four external magnets
55a-n, each equally spaced, although other numbers of magnets and
other magnet spacings may be employed depending on such factors as
magnet strength, the material that separates the internal and
external magnets (e.g., the material used for the enclosure wall
50), the torque exerted on the external magnets during rotation,
etc.
[0043] A motor 57 is coupled to the external magnets 55an, to the
central shaft 17 via a slideable connection 59 (e.g., a guide rail
connection) so as to slide vertically along the central shaft 17,
and to the internal magnet support 53 via a plurality of bearings
61a-n. The motor 57 preferably comprises both a rotational motor
portion 57a for providing rotational motion to the external magnets
55a-n (and thus to the internal magnets 51a-n and to the substrate
carriage 13) and a linear motor portion 57b for translating the
external magnets 55a-n (and thus the internal magnets 51a-n and the
substrate carriage 13) relative to the central shaft 17 (as
described below). Both the motor 57 and the central shaft 17 are
coupled to a supporting structure 63 (e.g. an equipment chassis, or
any other support structure). A second bellows 65 seals the chamber
11 from particles/contaminants generated by the slideable
connection 59 which exists between the motor 57 and the central
shaft 17.
[0044] In operation, to rotate the substrate carriage 13, the
rotational motor portion 57a of the motor 57 is energized (e.g., by
applying AC or DC power thereto as is known in the art) so as to
exert rotational force on the external magnets 55a-n (e.g., via a
rotor 64 of the rotational motor portion 57a). Due to magnetic
coupling between the internal and external magnets 51a-n, 55a-n, as
the external magnets 55a-n rotate under the applied rotational
force, the internal magnets 51a-n and the substrate carriage 13
coupled thereto also rotate. The bearings 61a-n allow the internal
magnet support 53 to rotate freely relative to the stationary
portions of the motor 57. The substrate carriage 13 (which is
fixedly coupled to the internal magnet support 53) thereby is
rotated, and may be rotated 360.degree. if the rotational motor
portion 57a is energized for a sufficient time period.
[0045] To raise and lower the substrate carriage 13, the linear
motor portion 57b of the motor 57 is employed to translate the
substrate carriage 13 relative to the central shaft 17. For
example, to lower the substrate carriage 13 from its raised
position (FIG. 4A) to its lowered position (FIG. 4B) wherein the
pair of substrate supports 21a-b extend below a top surface of the
temperature adjustment plate 15, the linear motor portion 57b of
the motor 57 is energized so that a translating portion 67 (e.g., a
motor shaft) of the linear motor portion 57b is extended. As the
translating portion 67 extends, due to contact with the stationary
structure 63, the remainder of the motor 57 is pushed away from the
stationary structure 63 while the central shaft 17 remains
stationary. In this manner, the motor 57 (with the exception of the
translating portion 67) slides along the slideable connection 59
toward the temperature adjustment plate 15, translating the
external magnets 55a-n, the internal magnets 51a-n and the
substrate carriage 13 (each of which are coupled either directly or
via bearings to the motor 57) toward the temperature adjustment
plate 15. The substrate carriage 13 thereby is lowered.
[0046] To raise the substrate carriage 13 from its lowered position
(FIG. 4B) to its raised position (FIG. 4A) wherein the pair of
substrate supports 21a-b are above the top surface of the
temperature adjustment plate 15, the translating portion 67 is
retracted. In response thereto, the remainder of the motor 57, and
the external magnets 55a-n, the internal magnets 51a-n and the
substrate carriage 13 coupled thereto, translate away from the
temperature adjustment plate 15. The substrate carriage 13 thereby
is raised (FIG. 4A). Preferably, a controller 69 (or the controller
C of FIG. 1) is coupled to the motor 57 and is programmed to
control the operation/timing of the raising, lowering and rotating
functions of the substrate carriage 13 described above.
[0047] FIGS. 5A and 5B are a front elevational view and a side
elevational view, respectively, of the chamber 11, employing a
preferred magnetically levitated and magnetically coupled substrate
handler 71, rather than the substrate handler 24 of FIGS. 2A and
2B. The substrate handler 71 comprises a blade 73 mounted on a
first end of a shaft 75, and a disk 77 mounted on a second end of
the shaft 75. The disk 77 is configured to support four vertically
arranged and radially disposed magnets 79a-d (e.g., four magnets
approximately equally spaced about the disk 77 as shown). The
magnets 79a-d preferably comprise electromagnets. As shown in FIGS.
5A and 5B the shaft 75 extends through an elongated opening 81
located in the bottom wall of the transfer chamber 11. The opening
81 extends from the temperature adjustment plate 15 toward the
processing chamber 29 a distance sufficient to place the substrate
handler 71 beneath one of the substrate seats 23a-c of the
substrate carriage 13 when the substrate handler 71 is in a
retracted position, and sufficient to place the blade 73 of the
substrate handler 71 above a substrate support (not shown) located
within the processing chamber 29. Thus the substrate handler 21 may
transport a substrate between the substrate carriage 13 and a
processing chamber 29.
[0048] An external channel wall 83 is sealed to (or may be
integrally formed with) the chamber 11 and is coextensive with the
opening 81. The external channel wall 83 is preferably configured
to allow magnetic coupling therethrough. The substrate handler 71
is disposed such that the disk 77 is contained within the external
channel wall 83, and such that the shaft 75 extends through the
elongated opening 81 into the chamber 11 a distance sufficient to
place the blade 73 at the same elevation as a top surface 82 of the
temperature adjustment plate 15.
[0049] A rail 85 extends along the length of the external chamber
wall 83. A bracket 87 having four external magnets 89a-d (e.g.,
magnets) is mounted to the rail 85 and is coupled to a motor 91
such that the motor 91 drives the bracket 87 forward and backward
along the rail 85. The external magnets 89a-d are vertically
arranged and are radially disposed along the inner surface of the
bracket 87 so as to be adjacent the outer surface of the external
channel wall 83 and so as to magnetically couple to the internal
magnets 79a-d. A distance sensor 93a-d is positioned adjacent each
internal/external magnet pair so as to sense the distance
therebetween. The sensors 93a-d, the external magnets 89a-d and the
motor 91 are each coupled to a controller 94 (or to the controller
C of FIG. 1), and the controller is adapted to independently adjust
the magnetization level of the external magnets 89a-d (e.g., by
adjusting the current supplied to each magnet 89a-d) so as to
maintain equal spacing between the magnet pairs, and thus to
maintain the robot blade 73 in a level position.
[0050] In operation, to transfer a substrate between the substrate
carriage 13 and the processing chamber 29, the substrate carriage
13 positions a substrate (not shown) above the blade 73 of the
substrate handler 71. The substrate carriage 13 then lowers such
that the blade 73 passes through the substrate seat 23 lifting the
substrate therefrom. The slit 27b that separates the chamber 11 and
the processing chamber 29 also is opened. Thereafter the motor 91
is energized so as to move the bracket 87 along the rail 85 toward
the processing chamber 29 at a speed which will maintain magnetic
coupling between the internal magnets 79a-d and the external
magnets 89a-d. As the bracket 87 moves along the rail 85 the
distance sensors 93a-d measure the distance between the internal
magnets 79a-d and the external magnets 89a-d. These distance
measurements are continually supplied to the controller 94 which is
adapted to adjust the magnetization levels of the external magnets
89a-d so as to maintain equal spacing between the various internal
and external magnet pairs. The controller 94 also adjusts the speed
at which the motor 91 moves the bracket 87 along the rail 85,
reducing the speed if the distance sensors 93a-d detect the bracket
87 is moving too quickly to maintain sufficient magnetic coupling
between the internal and external magnet pairs. After the substrate
handler 71 has traveled a sufficient distance such that the blade
73 is positioned above a substrate support (not shown) located
within the processing chamber 29, the motor 91 is deenergized. A
substrate lifting mechanism (not shown) such as a plurality of lift
pins or a wafer lift hoop elevate from the substrate support,
lifting the substrate from the blade 73. The motor 91 is then
energized causing the bracket 87 to move backward toward the
substrate carriage 13. When the blade 73 has cleared slit 27b, the
slit 27b closes and processing begins within the processing chamber
29. The substrate handler 71 remains in position next to the slit
27b until processing within the processing chamber 29 is
complete.
[0051] After processing within the processing chamber 29 is
complete the substrate handler 71 travels forward in the manner
described above to extract the substrate from the processing
chamber 29. While the substrate handler 71 is within the processing
chamber 29, the substrate carriage 13 lowers to a position below
the elevation of the substrate handler's blade 73. The substrate
handler 71 then retracts carrying the substrate into position above
the substrate carriage 13. The substrate carriage 13 elevates
lifting the substrate from the substrate handler's blade 73, and
simultaneously lifting any substrates positioned on the temperature
adjustment plate 15 therefrom. The substrate carriage 13 rotates
carrying the substrate retrieved from the processing chamber 29
(the "first" processed substrate) to a position above the
temperature adjustment plate 15 and carrying one of the substrates
lifted from the temperature adjustment plate 15 into position above
the substrate handler 71. The substrate carriage 13 then lowers
transferring the substrates from the substrate carriage 13 to the
temperature adjustment plate 15 and to the substrate handler 71. A
second substrate is then loaded into the processing chamber 29 as
described above and, depending on the configuration of the
temperature adjustment plate 15, the first processed substrate is
either cooled on the temperature adjustment plate 15, heated by the
temperature adjustment plate 15 (e.g., as an annealing step) or
immediately extracted therefrom by a front-end loader robot (not
shown). The front-end loader robot places a new "third" substrate
on a first side of the temperature adjustment plate 15 and extracts
the first processed substrate from the second side of the
temperature adjustment plate 15. It will be understood by those of
ordinary skill in the art that the sequence of substrate heating,
cooling and processing may vary according to the requirements of
the fabrication process being performed. For example, a substrate
may be degassed via the temperature adjustment plate 15 prior to
entry into the processing chamber 29, and/or cooled, annealed or
annealed and cooled by the temperature adjustment plate 15 after
processing within the processing chamber 29.
[0052] Note that an additional advantage of the inventive substrate
handling apparatus described herein is that various components
(e.g., the temperature adjustment plate 15, the substrate carriage
13, the substrate handler 24, the magnetically levitated and
magnetically coupled substrate handler 71, etc.) are each coupled
either directly or indirectly to only one surface of the chamber 11
(e.g., a bottom surface 11b as shown in FIGS. 4A and 4B).
Accordingly, as the walls of the chamber 11 deflect during
evacuation or venting of the chamber 11 (e.g., due to the
generation or elimination of a large pressure differential between
the interior and exterior environments of the chamber 11) substrate
transfer is unaffected as all substrate handling and/or supporting
components are identically affected by such deflections.
[0053] The foregoing description discloses only the preferred
embodiments of the invention, modifications of the above disclosed
apparatus and method which fall within the scope of the invention
will be readily apparent to those of ordinary skill in the art. For
instance, other methods of heating a substrate may be employed,
such as employing a heat lamp positioned along the top surface of
the chamber 11 to aid in heating of a substrate positioned on the
temperature adjustment plate 15 or of a substrate supported by the
substrate carriage 13. The specific shape of the various chamber
components, the coupling therebetween, the number of substrates to
be supported by the temperature adjustment plate 15 and/or the
substrate carriage 13 may vary as may the number of processing
chambers 29 coupled to the chamber 11. Although a magnetically
coupled substrate carriage and a substrate handler which is both
magnetically coupled and magnetically levitated are preferred,
substrate carriages and substrate handlers which are not
magnetically coupled or magnetically levitated may be employed.
Finally, although the invention is most advantageously employed
with a substrate handler preferably adapted only for transferring a
substrate along a straight line (a linear substrate handler), other
types of substrate handlers may be employed. In fact, the inventive
magnetically coupled and magnetically levitated substrate handler
may be employed within a transfer chamber such as that described in
U.S. Pat. No. 6,287,386 which requires the substrate handler to
transport substrates between the substrate carriage and various
processing or load lock chambers. The inventive magnetically
coupled substrate carriage may be employed in other transfer
chamber's such as those described in U.S. Pat. No. 6,287,386, as
may the temperature adjustment plate. The concept of heating or
cooling a substrate via a heating and/or cooling mechanism
contained within a transfer chamber, may be employed within other
chambers, and is not to be limited to the specific chambers
described herein.
[0054] Further modifications may be advantageously made to the
chamber. For instance, the cooling plate may be located above the
substrate carriage. To transfer a wafer to such a cooling plate an
empty slot of the substrate carriage is positioned below the
cooling plate, the substrate carriage then elevates to a position
above the cooling plate. The carousel rotates so as to position a
wafer above the cooling plate and then lowers the wafer onto the
cooling plate.
[0055] An inventive indexing pod door opener may eliminate the need
for a separate front end robot. Preferably the pod door opener is
provided with vacuum pump/vent capability so that the pod door may
operate as a load lock. The substrate carriage chamber's robot may
directly extract wafers from the pod door opener. The substrate
carriage chamber's robot stroke need not be lengthened because the
chamber is designed such that the robot can load/unload wafers from
processing chambers, and loading/unloading from one or more
processing chambers requires the same stroke as does loading and
unloading wafers from the pod door opener. Further, the pod door
opener may index vertically to eliminate the need for the pod door
receiver to move the pod door vertically to allow access to wafers
contained within the pod, and to eliminate the need for the
loading/unloading robot to index vertically. Finally, numerous
chambers configured in accordance with the invention may be coupled
via passthrough tunnels and may allow creation of a stage vacuum
system and/or a transfer chamber than is not exposed
atmosphere.
[0056] Accordingly, while the present invention has been disclosed
in connection with the preferred embodiments thereof, it should be
understood that other embodiments may fall within the spirit and
scope of the invention, as defined by the following claims.
* * * * *