U.S. patent application number 10/439521 was filed with the patent office on 2004-11-18 for sensor signal transmission from processing system.
Invention is credited to Beginski, David A..
Application Number | 20040226390 10/439521 |
Document ID | / |
Family ID | 33417824 |
Filed Date | 2004-11-18 |
United States Patent
Application |
20040226390 |
Kind Code |
A1 |
Beginski, David A. |
November 18, 2004 |
SENSOR SIGNAL TRANSMISSION FROM PROCESSING SYSTEM
Abstract
A processing system includes a plurality of chamber walls that
define a sealed environment. A sensor is positioned in the sealed
environment. In one embodiment, a power source, such as a
photoelectric cell, is positioned within the environment. In
another embodiment, a wireless transmission device is positioned
within the sealed environment. Methods for monitoring the
conditions within the sealed environment are also disclosed.
Inventors: |
Beginski, David A.;
(Gilbert, AZ) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
33417824 |
Appl. No.: |
10/439521 |
Filed: |
May 16, 2003 |
Current U.S.
Class: |
73/865.9 ;
438/14 |
Current CPC
Class: |
H01L 21/67259
20130101 |
Class at
Publication: |
073/865.9 ;
438/014 |
International
Class: |
H01L 021/66; G01M
019/00 |
Claims
1. A substrate processing system for processing a substrate, the
processing system comprising: a plurality of chamber walls, which
define a substantially sealed environment; a sensor system
positioned in the sealed environment; and a power source configured
to generate electrical energy that is positioned in the sealed
environment, wherein the power source is operatively connected to
the sensor system to supply electrical power to the sensor
system.
2. The system as in claim 1, wherein the power source comprises a
photoelectric cell.
3. The system as in claim 1, further comprising a wireless
transmission device that is positioned within the sealed
environment and is configured to transmit information outside of
the sealed environment.
4. The system as in claim 3, wherein the wireless transmission
device is an RF transmitter.
5. The system as in claim 3, wherein the wireless transmission
device is an infrared transmitter and the chamber walls include a
portion configured for the passage of infrared light.
6. The system as in claim 3, wherein the wireless transmission
device is powered by the power source.
7. The system as in claim 1, further comprising a control system
that is powered by the power source.
8. The system as in claim 1, wherein the power source comprises a
photoelectric cell and the system further comprises a supplemental
light source that is supplemental to ambient light provided to the
substrate processing system and is configured to provide light to
the photoelectric cell.
9. The system as in claim 8, wherein the supplemental light source
is positioned outside tie processing system and the chamber wall
includes a portion configured to allow the passage of light from
the supplemental light source.
10. The system as in claim 8, wherein the supplemental light source
is positioned inside the sealed environment.
11. The system as in claim 1, wherein the sensor is a substrate
detection apparatus for detecting the presence of a substrate that
is carried by an end effector of a substrate handling assembly
positioned within the substrate processing system, the substrate
detection apparatus comprising: a first receiving member that is
coupled to the end effector such that the first receiving member
moves with the end effector, the first receiving member comprising
a first receiving tip portion; a first connector member that is
operatively coupled to the first receiving member and is configured
to transmit light received by the first receiving member, and a
light detector that is operatively coupled to the first connector
member and is configured to detect an amount light transmitted by
the transmission member.
12. The system as in claim 11, wherein the system is positioned
within a sealed environment and the system further comprises a
wireless transmission device that is positioned in the sealed
environment and is configured to transmit information to outside of
the sealed environment.
13. The system as in claim 11, wherein the power source is
configured to provide power to the light detector.
14. The system as in claim 11, further comprising: a first
transmitting member that is coupled to the end effector such that
the first transmitting member moves with the end effector, the
first transmitting member comprising a first transmitting tip
portion; a second connector member that is operatively coupled to
the first transmitting member and is configured to transmit light
to the first transmitting member; a light source that is
operatively coupled to the second connector member and is
configured to transmit an amount light through the first
transmitting member.
15. The system as in claim 14, wherein the power source is a
photoelectric cell that provides power to the light source.
16. The system as in claim 1, wherein the sensor comprises a
temperature sensor.
17. The system as in claim 1, wherein the sensor comprises a gas
composition sensor.
18-27. (Canceled)
28. A method for monitoring conditions within a substantially
sealed environment of a processing system, comprising: providing a
sensor and a photoelectric cell inside the sealed environment;
collecting information from the sensor; and providing power to the
sensor from the photoelectric cell.
29. The method as in claim 28, wherein collecting information from
the sensor comprises detecting a presence of a substrate on an end
effector.
30. The method as in claim 28, wherein collecting information from
the sensor comprises measuring a temperature within the sealed
environment.
31. The method as in claim 28, wherein collecting information from
the sensor comprises measuring a gas composition within the sealed
environment.
32. A substrate processing system for processing a substrate, the
processing system comprising: a plurality of chamber walls, which
define a substantially sealed environment; a substrate detection
apparatus positioned in the sealed environment; the substrate
detection apparatus comprising a first receiving member that is
coupled to the end effector such that the first receiving member
moves with the end effector, a light detector that is operatively
coupled to the first receiving member and is configured to detect
an amount light received by the first receiving member; a first
transmitting member that is coupled to the end effector such that
the first transmitting member moves with the end effector, a light
source that is operatively coupled to the first transmitting member
and is configured to transmit an amount light through the first
transmitting member; and a power source that is also positioned in
the sealed environment, the power source comprising a photoelectric
cell.
33. The system as in claim 1, wherein the power source comprises a
battery.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This present invention relates to substrate processing and,
in particular, to methods and apparatus for conditions within a
substrate processing system.
[0003] 2. Description of the Related Art
[0004] Semiconductor devices, such as transistors, diodes, and
integrated circuits, are typically fabricated on a thin slice of
semiconductor material, termed a substrate or wafer. The substrate
is fabricated within a substrate processing station, which
typically includes one or more load locks, a wafer handling module
and one or more processing modules. The one or more load locks
provide a substantially particle free environment from which
substrates may be selectively withdrawn into the substrate handling
module. The substrate handling module typically includes a
substrate handler, which is configured to move substrates to/from
the one or more load locks and to/from the one or more processing
modules.
[0005] There are several general problems that are associated with
prior art substrate processing stations. For example, as the
substrate is moved within the processing station, the substrate can
become misaligned or mispositioned for various reasons. Such
mispositioning can result in damage to the substrate as it is moved
within the processing station and/or our errors in the fabrication
process if the mispositioning occurs within a processing module. As
such, some substrate processing system include several sensors to
monitor the position of the substrate position within the
processing station. Each sensor adds to the complexity and cost of
the processing station. These sensors are also typically difficult
to maintain.
[0006] The information gathered by the sensors is typically
transmitted to a control system that is positioned outside of the
processing station. The information is usually transmitted through
wires that extend through holes formed in the walls of the
processing station. To preserve the particle free environment
within the processing station, each hole must be suitably sealed.
In addition, the sensors may require power. Traditionally, the
power has been provided by wires that must also extend through
holes formed in the walls of the processing station. In other
arrangements, the sensors may be powered by batteries placed in the
sealed environment. However, the batteries must be periodically
replaced, which can be costly and time consuming.
SUMMARY OF THE INVENTION
[0007] A need therefore exists for a more simple and accurate
method for monitoring the position of the substrate within a
processing station.
[0008] One aspect of the present invention is a substrate
processing system for processing a substrate. The processing system
comprising a plurality of chamber walls, which define a
substantially sealed environment. A sensor is positioned in the
sealed environment. A power source is also positioned in the sealed
environment. In some embodiments, the power source comprises a
photoelectric cell.
[0009] Another aspect of the present invention is a method for
monitoring conditions within a substantially sealed environment of
a processing system. The method comprises providing a sensor and a
wireless transmission device inside the sealed environment,
collecting information from the sensor, and transmitting the
information from the sensor with the wireless transmission device
to a device located outside of the sealed environment.
[0010] Another aspect of the present invention is a substrate
processing system for processing a substrate. The processing system
comprises a plurality of chamber walls, which define a
substantially sealed environment. A sensor is positioned in the
sealed environment. A wireless transmission device is positioned
within the sealed environment and is configured to transmit
information outside of the sealed environment.
[0011] Yet another aspect of the present invention is method for
monitoring conditions within a substantially sealed environment of
a processing system. The methods comprises providing a sensor and a
photoelectric cell inside the sealed environment, collecting
information from the sensor, and providing power to the sensor from
the photoelectric cell.
[0012] Further aspects, features and advantages of the present
invention will become apparent from the following description of
the preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] These and other features, aspects and advantages of the
present invention will now be described with reference to the
drawings of preferred embodiments which are intended to illustrate
and not to limit the invention. The drawings comprising:
[0014] FIG. 1 a schematic top plan view of a substrate processing
system.
[0015] FIG. 2 is a bottom plan view of an end effector of the
substrate processing system and a portion of a substrate detection
system having certain features and advantages according to the
present invention.
[0016] FIG. 3 is a front view of the end effector and substrate
detection system of FIG. 2.
[0017] FIG. 4 is a top plan view of a rod of the substrate
detection system of FIG. 2.
[0018] FIG. 5 is schematic illustration of the substrate detection
system of FIG. 2.
[0019] FIGS. 6A-C are schematic illustrations showing the operation
of the substrate detection system.
[0020] FIGS. 7A-C are schematic illustrations showing the operation
of a modified embodiment of the substrate detection system.
[0021] FIG. 8 is a top plan view of the end effector with a portion
of another modified embodiment of a substrate detection system.
[0022] FIG. 9 is a front view of the end effector and substrate
detection system of FIG. 8.
[0023] FIG. 10 is a top plan view of a rod of the substrate
detection system of FIGS. 8 and 9.
[0024] FIG. 11 is a schematic illustration of the substrate
detection system of FIGS. 8 and 9.
[0025] FIGS. 12A and 12B are schematic illustrations of a front
view of the detection system of FIGS. 8 and 9 showing the operation
the substrate detection system.
[0026] FIGS. 13A-C are schematic illustrations of a top view of the
detection system of FIGS. 8 and 9 showing the operation of the
substrate detection system.
[0027] FIG. 14 is a schematic illustration of another modified
embodiment of a substrate detection system.
[0028] FIG. 15 is a schematic illustration of still another
modified embodiment of a substrate detection system.
[0029] FIG. 16 is a schematic illustration of a temperature sensor
system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0030] FIG. 1 illustrates an exemplary substrate processing system
10 that comprises two load locks 12, a substrate handling module
14, and two substrate processing modules 16. The substrate handling
module 14 comprises a housing 18, which defines a substrate
handling chamber 20. The substrate handling chamber 20 is
preferably substantially closed and under vacuum. However, in
modified embodiments, the substrate handling chamber can be kept a
higher pressures (e.g., atmospheric).
[0031] The load locks 12 can be adapted for holding, among other
things, a cassette of substrates, a plurality of single substrates
and/or a single substrate. The load locks 12 are connected to the
substrate handling module 14 by an opening, which is selectively
opened and closed by a gate valve 22. In a similar manner, the
processing modules 16 are connected to the substrate handling
chamber 18 by openings, which are also selectively opened and
closed by gate valves 24.
[0032] A substrate handler 26 is positioned within the substrate
handling chamber 20. The substrate handler 26 is configured to
transfer a substrate 28 to, from and between the load locks 12 and
the processing modules 16. The substrate handler 26 includes an end
effector 30, which is configured to fit between the openings that
connect the load locks 12 and processing chambers 16 to the
substrate handling module 14. The substrate handler 26 also
includes a robot arm assembly 32. The robot arm assembly 32 is
mounted to a support member (not shown) and can control movement of
the end effector 30 in any manner.
[0033] As shown in FIGS. 2 and 3, in the illustrated embodiment,
the end effector 30 comprises a simple paddle or spatula, which
supports the substrate 28 by contacting a lower surface 36 of the
substrate 28 with an upper surface 38 of the paddle 30. The paddle
30 in some embodiments may be made of quartz so that it can engage
a substrate at high temperatures (e.g,. above 1000 degrees
Celsius). Of course, other suitable materials may be used.
[0034] In the embodiments illustrated herein and described below,
the substrate detection system 40 is shown with a paddle-type end
effector 30. However, it should be appreciated that certain
features and advantages of the present invention can be used with
other types of end effectors 30. For example, the end effector may
be a gridded type spatula as described in U.S. Pat. No. 6,331,023,
a forked type end effector as described in U.S. Pat. No. 6,293,749,
a Bernoulli wand as described in U.S. Pat. No. 6,242,718, an edge
grip type end effector, or a vacuum grip end effector. The
detection system 40 may also be used with a substrate carrier such
as the substrate carrier described in U.S. patent application Ser.
No. 09/256,743.
[0035] With reference to FIGS. 2-5, the end effector 30 preferably
includes a substrate detection system 40 having certain features
and advantages according to the present invention. In the
illustrated embodiment, the detection system 40 comprises a
detection portion 42 (see FIGS. 2 and 3) and a
receiving/transmitting portion 44 (see FIG. 5). The detection
portion 42 is preferably configured such that it moves with the end
effector 30. In contrast, the receiving/transmitting portion 44 can
be located on the robot arm assembly 32 and/or the support member.
In the illustrated embodiment, the detection portion 42 and the
receiving/transmitting portion receive and transmit light through
light pipes, which may have a number of straight and bent sections
to allow receiving/transmitting surfaces to be at the appropriate
positioned as will be explained in more detail below.
[0036] In the illustrated embodiment, the detection portion 42
comprises a transmitting light pipe 48 and a receiving light pipe
50. Both light pipes 48, 50 are preferably formed from clear
optical material and form a wave guide for transmitting light,
preferably visible light. In the illustrated embodiment, the
transmitting light pipe 48 includes a straight section 54, a bent
section 56 and a tip portion 58 (see also FIG. 2). The straight
section extends along a first longitudinal side 60 of the end
effector 30. The curved section 56 preferably curves about a front
corner 62 of the end effector 30 such that the tip portion 58 lies
in front of the end effector. In a similar manner, the receiving
light pipe 50 of the illustrated embodiment also includes a
straight section 64, a bent section 66 and a tip portion 68. The
straight section 64 extends along a second longitudinal side 70 of
the end effector 30. The bent section 66 curves about a second
front corner 72 of the end effector 30 such that the tip portion 68
of the receiving light pipe 50 also lies in front of the end
effector 30.
[0037] In the illustrated embodiment, the tip portions 58, 68 are
located in front of the end effector 30 and the straight portions
54, 64 extend along the longitudinal sides 60, 70 of the end
effector 30. However, it should be appreciated that the illustrated
configuration of the bent and straight portions are merely
exemplary. For example, in one modified embodiments, one or both
tip portions 58, 68 can be located on the sides of the end effector
30. In another embodiment, the straight portions 54, 64 can be
positioned underneath the end effector 30. In still another
embodiments, the light pipes 48, 50 can be located adjacent to each
other.
[0038] With reference to FIG. 4, the tip portions 58, 68 include
transmitting/receiving surfaces 71. As shown in FIG. 3, the tip
portions 58 are angled such that the transmitting/receiving
surfaces point towards the lower surface 36 of the substrate 28
that is properly positioned on the end effector 30. More
specifically, the tip portions 58, 68 are orientated such that a
light beam emanating from the transmitting light pipe 48 will be
reflected off of the lower surface 36 of the substrate 28 and be
collected or received by the receiving light pipe 50.
[0039] As seen in FIG. 5, in the illustrated embodiment, the
straight section 54 of the transmitting light pipe 48 is
operatively coupled to a connecting member 74, which preferably
comprises a flexible light transmitting material, such as, for
example, a fiber optic cable. The connecting member 74 is, in turn,
connected to a light source 76. In one embodiment, the light source
76 is a 0.5 mW laser with a wave length of approximately 689
nanometers and in another embodiment the light source is a 48 Watt
quartz lamp. A lens 78 is preferably provided on the flexible
member 74 between the interface be the connecting member 74 and the
transmitting light pipe 48 for gathering light transmitted by the
connecting member 74.
[0040] In a similar manner, in the illustrated embodiment, the
straight section 64 of the receiving light pipe 50 is connected to
a second connecting member 80, which also preferably comprises a
flexible light transmitting material, such as, for example, a fiber
optic cable. As with the first connecting member 74, the second
connecting member 80 includes a lens 82 at the interface with the
receiving light pipe. The second connecting member 80 is connected
to a light sensor 84 (e.g., a photo cell sensor), which is
preferably operatively connected to a control system 86, as will be
explained in more detail below.
[0041] With reference to FIGS. 6A-C, the operation of the detection
system 40 will now be described. In FIG. 6A, the substrate 28 is
properly positioned on the end effector 30. The tip portions 58, 68
of the transmitting and receiving light pipes 48, 50 are orientated
such the light 88 generated by the light source 76 (FIG. 5) and
emitted from the transmitting light pipe 48 is reflected off the
substrate 28 and received by the receiving light pipe 50. The light
is transmitted through the receiving light pipe 50 and the flexible
member 80 and detected by light sensor 84 (FIG. 5), which plight
pipeuces an appropriate signal to the control system 68 (FIG. 5) to
indicate that the substrate 28 is present and in the proper
position.
[0042] In FIG. 6B, the substrate 28 is improperly positioned on the
end effector 30. With the substrate 28 in this position, the light
88 emitted by the transmitting light pipe 48 is not received by the
receiving light pipe 50 because it is reflected at an incorrect
angle. As such, no light or insufficient light is detected by the
light sensor 84 (FIG. 5) and an appropriate signal or lack of
signal can be sent to the control system 86 (FIG. 5) indicating
that the substrate 28 is improperly aligned. In a similar manner,
as shown FIG. 6C, when a substrate 28 is not positioned on the end
effector 30, the light 88 emitted by the transmitted light pipe 48
is not reflected and is not received by the receiving light pipe
50. The light sensor 84 (FIG. 5), therefore, does not receive a
light signal and an appropriate signal can be sent to the control
system 86 (FIG. 5).
[0043] In a modified embodiment, the end effector 30 can be
provided with one or more additional pairs of transmitting and
receiving light pipes. The additional pairs can be used in
combination with the transmitting and receiving light pipes
described above to determine the position of the substrate on the
end effector 30. That is, the additional pair can be used to
determine the edge of the substrate 28.
[0044] For example, as shown in FIGS. 7A, a second pair 90 of
transmitting and receiving light pipes 48', 50' can be spaced
further from the tip of the end effector 30. Though not
illustrated, it will be understood that each of the pairs ins
angled upwardly to bounce and receive light off the wafer bottom
surface, as illustrated in FIGS. 6A-C. When no wafer is present, as
illustrated in FIG. 7A, neither of the receiving light pipes 50,
50' receives light and thus the control system 86 (FIG. 5) would
indicate that a substrate is not present. When a substrate 28 is
present as shown in 7B, the receiving light pipe 50 of the first
pair 91 receives reflected light while the receiving light pipe 50'
of the second pair 90 does not. Such a situation indicates that a
substrate 28 is present on the end effector 30 and is in a position
wherein the edge 92 of the substrate 28 lies between the first and
second pairs of light pipes 91, 90. When the substrate 28 is
positioned as illustrated in FIG. 7C, the receiving light pipes 50,
50' of both pairs 91, 90 receive reflected light. Such a situation
indicates that the substrate 28 is present and that the edge 92 of
the substrate 28 is located past the second pair of light pipes
90.
[0045] It should be noted that, in the above-described embodiments,
the light sensor 84 (FIG. 5) can be configured such that it is
powered (i.e., generates electricity) from the light received from
the light source 76. Such an arrangement eliminates the need for a
power source (e.g., a battery) for the light sensor 84.
[0046] FIGS. 8-11 illustrate another embodiment of a substrate
detection system 100 having certain features and advantages
according to the present invention. The illustrated detection
system 100 comprises a shadow detection portion 102, that as with
the previous embodiment, is configured to move with the end
effector 30.
[0047] As with the previous embodiment, the detection portion 102
comprises a light pipe that is preferably formed from optically
transparent material that forms a wave guide for transmitting light
(preferably visible light) as will be explained below. In the
illustrated embodiment, the detection portion 102 includes a
straight section 106 and a tip portion 108, which is best seen in
FIG. 10. As shown, in FIG. 10, the tip portion 108 preferably
comprises a well-polished face 110 that forms approximately a 45
degree angle with respect to a longitudinal axis 112 of the
elongated portion 106. The tip portion 108 is configured to detect
a shadow as will be explained in more detail below. As best seen in
FIGS. 8 and 9, in the illustrated embodiment, the tip portion 108
is generally located near a front end 114 of the end effector 30.
However, this particular position is merely exemplary. For example,
the tip portion 108 may be located on along a side 116 of the end
effector 30. In still other embodiments, the elongated portion 106
may extend under the end effector 30. The elongated portion 106 may
also be bent, for example, in a manner as shown FIGS. 2 and 3.
[0048] With reference now to FIG. 11, the elongated portion 106 is
preferably connected to a connecting member 120, such as the
flexible connecting members described above. The flexible
connecting member 120 is connected to a photo cell or light sensor
122, which is preferably operatively connected to a control system
124 as will be explained in more detail below. The flexible
connecting member 120 preferably includes a lens 126 at the
interface between the flexible connecting member 120 and the
elongated portion 106.
[0049] The operation of the detection system 100 will now be
described with reference to FIGS. 12A and 12B. In FIG. 12A, the
substrate 28 is positioned on the end effector 30. The tip portion
108 of the detection portion 102 is under the substrate 28. As
such, the substrate 28 blocks the light 128 (e.g., visible light)
from being received by the detection portion 102. That is, the tip
portion 108 is located in the "shadow" of the substrate 28. As
such, no light or a very small amount light is being received by
the tip portion 108 and no or a very small amount of light is
transmitted to the light sensor 122. The control system 124 (FIG.
11) can be calibrated to interpret such a situation as indicating
that a substrate is present on the end effector 30.
[0050] The light 128 can be ambient light (i.e., light typically
present in the processing system 10) or light from a supplemental
light source (i.e., a light source added specifically to aid the
detection system 100). The ambient light or supplemental light
source may be positioned within or outside the processing system 10
(FIG. 1). In the embodiments where the ambient or supplemental
light is positioned outside the processing system 10, the
processing system 10 may include windows for allowing the ambient
or supplemental light to pass into the processing or handling
chambers 20.
[0051] In FIG. 12B, there is no substrate 28 on the end effector
30. As such, the tip portion 108 is no longer in the "shadow" of
the substrate 28. The tip portion 108, therefore, can receive
ambient light 128 or light from a supplemental light source. Such
light is transmitted to the light sensor 122, indicating that a
substrate is not present.
[0052] In a modified embodiment, the end effector can be provided
with one or more additional shadow detection portions. The shadow
detection portions can be used in combination to determine the
position of a substrate on the end effector in a manner similar to
that described above.
[0053] For example, as shown in FIG. 13A, the end effector 30
includes a second shadow detection portion 130 that is be distanced
further from the tip of the end effector as compared to the first
detection portion 102. While not shown, the tip can be angled as
described with respect to FIG. 10. When a substrate is absent as
illustrated in FIG. 13A, both shadow detection portions 102, 130
receive light and thus the control system indicates the absence of
a substrate. When a substrate 28 is positioned as shown in 13B, the
first shadow detection portion 102 is under the shadow of the
substrate 28 while the second detection portion 130 receives light.
Such a situation indicates that a substrate 28 is present on the
end effector 30 and that the edge 132 of the substrate is located
between the tip portions of the first and second shadow detection
portions 102, 130. When the substrate 28 is positioned as
illustrated in FIG. 13C, the tips of the shadow detection portions
102, 130 are both under the shadow of the substrate 28. This
situation indicates that the substrate 28 is present and that the
edge 132 of the substrate 28 is positioned beyond the tip of the
second shadow detection portion 130.
[0054] In another modified embodiment, the detection systems 100 of
FIGS. 8 or 13A can include an ambient light sensor 136 (See FIG.
14). The ambient light sensor 136 can be positioned on the end
effector 30 such that it is not affected by the presence or absence
of a substrate. In other embodiments, the ambient light sensor 136
can be positioned on one or more stationary portions of the
substrate processing system 10 (FIG. 1) or on a portion of the
substrate handler 26 (FIG. 1). As shown in FIG. 14, the ambient
light sensor 136 is preferably connected by a member 138 to a
second light sensor 167, which is also connected to the control
system 124. The presence or absence of a substrate can therefore be
determined by comparing the signals of the first light sensor 22 to
second light sensor 167. Such an arrangement reduces errors that
may be associated with changes in the ambient light and reduces the
time necessary to calibrate the detection system.
[0055] The embodiments described above have several advantages as
compared to prior art substrate detection systems. For example,
prior art substrate detection systems typically require multiple
sensors to sense the position of the substrate as the substrate is
moved between the load locks, the substrate handling module and the
processing modules. In the illustrated embodiments, the detection
portions of the detection system preferably are mounted onto and
move with the end effector. This arrangement reduces the need for
multiple sensors and thereby results in fewer parts, less
installation time and less maintenance time. In addition, the
detection portions preferably are made of quartz, which can
withstand temperatures up to about 1100 degrees Celsius. As such,
the detection portions may even be inserted into the processing
modules of the substrate processing system. In contrast, mirrors
and electrical sensors, which are often used in prior art detection
systems, typically cannot be inserted in the processing modules due
to the high temperatures.
[0056] FIG. 15 illustrates another embodiment of a substrate
detection system wherein like numbers are used to refer to parts
similar to those of FIG. 5. In this embodiment, the detection
system 150 includes an internal power source 152 and a wireless
transmission device 154. As will be explained in more detail below,
the wireless transmission device 154 can be used to transmit
information regarding the position of the substrate between a
sealed processing environment 153 an outer clean room or gray room
157, which is separated by a wall 155 from the sealed processing
environment 153. That is, the information is transmitted through
the walls 155 without the need for wires that extend through such
walls 155. With reference to FIG. 1, in the illustrated embodiment,
the wall 155 corresponds to the walls of the substrate processing
system 10 (i.e., the walls of the load locks 12, substrate handling
module 14, and processing chambers 20). As such, the sealed
processing environment 153 is the space within the processing
system 10, which is surrounded, at least partially, by the outer
clean room or gray room 157.
[0057] In a preferred embodiment, the internal power source 152
comprises a photoelectric cell or "solar" cell, which can convert
ambient light or light from a supplemental light source to
electricity. The electricity generated by the internal power source
152 can be used to power the light source 76, the light detection
device 84, and/or the control system 86, and/or the transmission
device 154. The signals from the control system are preferably
transmitted by the wireless communication device 154 to a more
comprehensive substrate processing control system 156, which is
preferably located outside or external to the sealed environment
153 (i.e., the substrate processing system 10). The signals can be
used by the substrate processing control system 156 to monitor the
position of the substrate as it moves through the processing system
10. The wireless communication device 154 is also preferably
powered by the power source 152. In one embodiment, the wireless
communication device 154 is a low power IR transmitter. In such an
embodiment, the wall 155 preferably includes a window through which
the IR signal can be transmitted. In another embodiment, the
wireless communication device 154 is a low power RF transmitter.
Preferably, the detection system 150 also includes a regulator and
a storage cap battery that can be charged by the solar cell (power
source) 152 to provide power during periods of darkness.
[0058] The embodiment described above has several advantages. For
example, as compared to an external power source (e.g., a direct
electrical connection), there are no physical connections (e.g.,
wires) between the external power source and the components of the
detection system. Such wires increase the complexity of the system
and may become damaged during the operation of the wafer handler.
Wire movement may also cause particle generation and require
additional seals in the processing system. Other internal power
sources, e.g. , batteries, require frequent downtime to open the
processing system 10 and replace or maintain the power source when
the power is drained. The wireless communication device also
eliminates physical connections (e.g., wires) between the substrate
detection system 150 and the substrate control system 160, which
further reduces the complexity of the detection system 150. In
addition, the processing system can be retrofitted with additional
sensors without adding additional wires, which can create more
particle generation.
[0059] It should be appreciated that certain features of the system
150 described above can also be used with the embodiments described
with reference to FIGS. 1-14. Moreover, in certain embodiments, the
internal power source 152 may be used without the wireless
communication device 154 and in other embodiments, the wireless
communication device 154 may be used without the internal power
source 152.
[0060] It should also be appreciated that the internal power source
and/or the wireless communication device may be used to transmit
information between devices in the sealed processing environment
and the outer room. In particular, an internal power source and/or
a wireless communication device can be mounted on other devices
that move within the sealed substrate processing environment apart
from the substrate detection system described above. In other
embodiments, the internal power source and/or the wireless
communication device described above may be used with sensors on
other devices or other moving parts within the sealed semiconductor
processing chamber, such as, for example, temperature sensors on a
rotating support structure or surrounding ring inside a processing
chamber. The internal power source and/or the wireless
communication device can be used with other types of sensors
besides or in addition to the substrate detection system.
[0061] For example, as shown in FIG. 16, the internal power source
152 and/or the wireless communication device 154 may be used with a
temperature measurement system (e.g., a series of temperatures
sensors 160) or a gas composition detection sensor 162. In the
illustrated embodiment, the temperature sensors and gas sensors are
placed on a generally flat circular susceptor 164, which is
supported by a spider 166 within the sealed environment 153 of, for
example, a processing chamber. The spider 166 is mounted on a
tubular shaft 168 which may extends through the processing chamber.
Details of such an arrangement together with a drive mechanism can
be found in U.S. Pat. No. 4,821,674, which is incorporated herein
by reference. In the illustrated embodiment, the wireless
communication device 154 is placed on the spider. In a modified
arrangement, the wireless communication device can be powered by an
internal power source that is mounted, for example, on the spider
166.
[0062] Of course, the foregoing description is that of preferred
embodiments of the invention and various changes, modifications,
combinations and sub-combinations may be made without departing
from the spirit and scope of the invention, as defined by the
appended claims.
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