U.S. patent application number 11/052161 was filed with the patent office on 2005-06-16 for sensor device for non-intrusive diagnosis of a semiconductor processing system.
This patent application is currently assigned to Applied Materials, Inc.. Invention is credited to Hunter, Reginald.
Application Number | 20050126315 11/052161 |
Document ID | / |
Family ID | 21887524 |
Filed Date | 2005-06-16 |
United States Patent
Application |
20050126315 |
Kind Code |
A1 |
Hunter, Reginald |
June 16, 2005 |
Sensor device for non-intrusive diagnosis of a semiconductor
processing system
Abstract
A sensor device, for diagnosing a processing system, generally
includes a support platform and one or more sensors mounted on the
support platform. The sensor senses a condition, such as direction
or inclination or acceleration in one or two axes, of the sensor
device and outputs a signal indicative thereof, which is then
transferred to a device on or near the processing system. The
support platform generally has physical characteristics, such as
size, profile height, mass, flexibility and/or strength,
substantially similar to those of the substrates that are to be
processed in the processing system, so the sensor device can be
transferred through the processing system in a manner similar to
the manner in which production substrates are transferred through
the processing system.
Inventors: |
Hunter, Reginald; (Round
Rock, TX) |
Correspondence
Address: |
MOSER, PATTERSON & SHERIDAN, LLP/
APPLIED MATERIALS, INC.
3040 POST OAK BOULEVARD, SUTIE 1500
HOUSTON
TX
77056
US
|
Assignee: |
Applied Materials, Inc.
|
Family ID: |
21887524 |
Appl. No.: |
11/052161 |
Filed: |
February 7, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11052161 |
Feb 7, 2005 |
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10445598 |
May 27, 2003 |
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10445598 |
May 27, 2003 |
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10083899 |
Feb 27, 2002 |
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6677166 |
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10445598 |
May 27, 2003 |
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10084290 |
Feb 27, 2002 |
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6642853 |
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10084290 |
Feb 27, 2002 |
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09816806 |
Mar 23, 2001 |
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6468816 |
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09816806 |
Mar 23, 2001 |
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09036247 |
Mar 6, 1998 |
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6244121 |
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Current U.S.
Class: |
73/865.9 |
Current CPC
Class: |
Y10T 29/49004 20150115;
G03F 7/707 20130101; H01L 21/67288 20130101; Y10T 29/49769
20150115; H01L 21/67248 20130101; H01L 21/67167 20130101; H01L
21/67253 20130101; H01L 21/67242 20130101; G03F 7/70708 20130101;
G03F 7/7085 20130101; H01L 21/67196 20130101; H01L 21/681 20130101;
H01L 21/67259 20130101; Y10S 414/135 20130101 |
Class at
Publication: |
073/865.9 |
International
Class: |
G01N 019/00 |
Claims
What is claimed:
1. An apparatus for providing information from within a processing
system, the apparatus comprising: a support platform adapted for
robotic transfer between a central transfer chamber and a substrate
support structure in a vacuum processing chamber of the processing
system; and a device disposed on the support platform for obtaining
a signal indicative of information obtained from within the
processing system.
2. The apparatus of claim 1, wherein the support platform and the
device are sized to pass through a slit valve separating the
central transfer chamber and the processing chamber.
3. The apparatus of claim 1, wherein the information provided by
the device is indicative of the position of the support platform
within the processing system.
4. The apparatus of claim 1, wherein the device provides optical
information.
5. An apparatus for providing information from within a processing
system, the apparatus comprising: a support platform adapted for
robotic transfer between a central transfer chamber and a substrate
support structure in a vacuum processing chamber of the processing
system; and a transmitter coupled to the support platform and
adapted to broadcast a signal indicative of information obtained
from within the processing system, wherein the transmitter is
configured to transmit the signal.
6. The apparatus of claim 5, further comprising a receiver disposed
remotely from the support platform for receiving the wireless
signal from the transmitter.
7. The apparatus of claim 6, wherein the receiver is disposed
outside the processing system.
8. The apparatus of claim 7, wherein the receiver is mounted to an
exterior of the processing system.
9. An apparatus for providing information from within a processing
system, the apparatus comprising: a support platform adapted for
robotic transport between a central transfer chamber and at least
one processing chamber; and a temperature sensor disposed on the
support platform.
10. The apparatus of claim 9, wherein the apparatus is sized to
pass through a slit valve separating the central transfer chamber
and the at least one processing chamber.
11. The apparatus of claim 9, wherein the temperature sensor
measures a temperature of a process gas within the at least one
processing chamber.
12. The apparatus of claim 11, further comprising: a device
disposed remotely from the support platform for receiving the
temperature of the process gas.
13. The apparatus of claim 9, wherein the temperature sensor
transfers an optical signal indicative of temperature
information.
14. A method of providing information from within a processing
system, the method comprising: attaching a device for obtaining
information from within the processing system to a support platform
adapted for robotic transfer between a central transfer chamber and
a substrate support structure in a vacuum processing chamber of the
processing system; utilizing the device to collect information
obtained from within the processing system; and removing the device
from the processing chamber.
15. The method of claim 14, wherein the information comprises
optical information.
16. The method of claim 14, wherein the information comprises
information indicative of the position of the support platform
within the processing system.
17. The method of claim 14, wherein the device is a temperature
sensor that measures a temperature of a process gas within the
processing chamber.
18. The method of claim 14, wherein the device is a temperature
probe having an array of temperature sensors configured to detect a
thermal gradient across the length of the probe.
19. The method of claim 14, wherein the device provides a metric
indicative of motion of the support platform within the processing
system.
20. The method of claim 14, wherein the device measures a
temperature of the support platform.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of copending U.S. patent
application Ser. No. 10/445,598, filed May 27, 2003, which is a
continuation of copending U.S. patent application Ser. No.
10/083,899, filed Feb. 27, 2002 and issued as U.S. Pat. No.
6,677,166, and copending U.S. patent application Ser. No.
10/084,290, filed Feb. 27, 2002 and issued as U.S. Pat. No.
6,642,853, which are divisional applications of U.S. patent
application Ser. No. 09/816,806, filed Mar. 23, 2001 and issued as
U.S. Pat. No. 6,468,816, which is a divisional application of U.S.
patent application Ser. No. 09/036,247, filed Mar. 6, 1998 and
issued as U.S. Pat. No. 6,244,121. All of the above are hereby
incorporated by reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention generally relates to methods and
apparatuses for testing or aligning the various parts of a
processing system. Specifically, the present invention relates to
methods and apparatuses for leveling and aligning the processing
system and the various structures within the processing system that
support and/or transfer processing objects, such as substrates,
through the processing system so that the processing system and
each structure is substantially level and so that each structure
receives, supports and/or transfers the substrates in substantially
the same inclination and without slippage of or damage to the
substrates.
[0004] 2. Background of the Related Art
[0005] Processing systems for processing 100 mm, 200 mm, 300 mm or
other diameter substrates are generally known. Typically, such
processing systems have a centralized transfer chamber mounted on a
monolith platform. The transfer chamber is the center of activity
for the movement of substrates being processed in the system. One
or more process chambers mount on the transfer chamber at slit
valves through which substrates are passed by a substrate handler,
or robot. Access to the transfer chamber from the clean ambient
environment is typically through one or more load lock chambers
attached at other slit valves. The load lock chambers may open to a
very clean room, referred to as the white area, or to an optional
substrate handling chamber, typically referred to as a
mini-environment.
[0006] In addition to the substrate handler disposed within the
transfer chamber, a processing system may have several other
structures, including, but not limited to, indexers in the load
lock chambers, lift pins in the process chambers, and substrate
chucks in the process chambers, which will support or handle the
substrates in one manner or another. The lift and support
structures within the processing system may exchange substrates
more rapidly, without slippage or backside contamination of the
substrates, if the lift and support structures are level.
Additionally, the extremely fine and delicate nature of the
circuits and other structures being constructed on the substrates
may require that the processing system as a whole, and particularly
each substrate support structure, be set as near to level as
possible. Typically, assemblers or operators of the processing
systems may try to ensure that, at a minimum, the various substrate
support structures are in alignment relative to each other, so that
even if each support structure is not perfectly level, at least
they are all at the same inclination. Additionally, the assemblers
or operators will attempt to ensure that the substrate support
structures, which move the substrates laterally, accelerate and
decelerate at suitable rates and without discontinuous, or jerking,
motion, so that the substrates do not slip on the support
structure. Failure to ensure that the processing system and/or each
of the substrate support structures is properly level and/or
aligned and is operating smoothly may cause damage to or improper
processing of the substrates and can reduce the throughput of the
processing system since substrate exchanges may not be performed at
maximum speed.
[0007] Relative alignment of the substrate support structures is
typically more important than absolute leveling of the entire
processing system since substrate exchange handling can result in
significant slippage due to improper alignment. When the substrate
support structures, within a processing system, are improperly
aligned, however, the support structures do not hold the substrates
at about the same inclination, or tilt. Thus, when one support
structure transfers a substrate to another support structure, such
as when the lift pins remove a substrate from a blade of the
transfer chamber substrate handler or place a substrate onto the
substrate chuck in a process chamber, one point of the substrate
will always touch the receiving support structure before other
points do. If substantial motion occurs prior to the remaining
points making contact, then the substrate can slip. In this manner,
potentially contaminating particles may be scraped from the
contacting points of the substrate causing backside contamination
of the substrate. These particles may eventually work their way
around to the top of the substrate and be deposited on the
processed surface of the substrate, thereby contaminating the micro
circuits or other structures constructed thereon. Additionally,
when the substrate does not touch a receiving support structure
with all points in very close alignment, then the substrate may be
shifted from its proper, or expected, position, so that the
substrate is off-center. An off-center substrate may undergo uneven
or otherwise improper processing or may come in contact with
surfaces or objects within the processing system that will
contaminate the substrate, create potentially contaminating
airborne particles or even break the substrate. Thus, exchanges of
the substrate between lifting or supporting structures within the
processing system requires a coplanar interface. If the exchange is
not coplanar, then the substrate will have the propensity to slip,
resulting in misalignment and backside contamination of the
substrate.
[0008] When a processing system as a whole is improperly leveled,
the system chambers, such as the transfer chamber, are inclined at
an angle and can cause problems with the handling and processing of
substrates and can exacerbate the problems with substrate support
structures that are further inclined relative to the processing
system. Since the substrate support structures are mounted to the
processing system, if the processing system is inclined and the
support structures are level relative to the processing system,
then the support structures will also be inclined, though the
support structures may, nevertheless, be aligned with each other.
When the processing system is inclined, but the support structures
are aligned, then the processing system may still operate properly,
but possibly at a lower than optimum speed. Additionally,
performance of certain functions that are sensitive to gravity may
be affected by the inclination of the system. When a transfer
chamber substrate handler, for example, accelerates a substrate in
a manner that may be appropriate for a level system, the substrate
may, nevertheless, slide off-center due to the inclination, thereby
exposing the substrate to potential damage from particles that may
be generated by the slide or to potential collision with a surface
or object in the processing system that requires a relatively close
centering tolerance of the substrate for clearance.
[0009] The substrate support structures typically may be leveled
independently within the processing system. Thus, after the
transfer chamber and the processing chambers are leveled as a
whole, the transfer chamber substrate handler or the process
chamber lift pins or chuck may be additionally leveled
independently. It is even possible for a substrate handler to be
fairly level while the transfer chamber is significantly inclined,
or vice versa. In such manner, the substrate handler may be aligned
with an opening through which it passes substrates to and from a
process chamber on one side of the transfer chamber, yet be out of
alignment with an opening for a process chamber on the opposite
side of the transfer chamber. Therefore, the transfer chamber
substrate handler must be fairly closely aligned with the
inclination of the transfer chamber to permit proper functioning of
the entire system.
[0010] FIG. 1a shows a prior art method of determining the
inclination of a transfer chamber substrate handler 10. The
transfer chamber 12 is shown with a lid 14 partially lifted to
expose the interior of the chamber body 16. The substrate handler
10 is mounted in about the center of the transfer chamber 12 and
rotates about a center point. The substrate handler 10 extends a
blade 18 to insert a substrate 20 through a slit valve opening 22
to access a process chamber (not shown) or a load lock chamber (not
shown) mounted to the facets 24. To determine the inclination of
the blade 18, an operator places a level, such as a bubble level,
26 onto the blade 18 and reads the inclination through a window in
the level 26. The level 26 may be placed directly onto the blade
18, or the level 26 may be placed onto a substrate 20 sitting on
the blade 18. The inclination of the blade 18 must be measured in
each relevant direction with the blade 18 retracted as shown and
with the blade 18 extended through the slit valve 22, so the
substrate handler 10 can function properly throughout all of its
movements. The actual leveling of the substrate handler 10 may
involve adjusting the transfer chamber 12 relative to a support
platform (not shown), adjusting the base 28 relative to the
transfer chamber 12 and adjusting the arms 30, linkages 32 and
blade wrist 34.
[0011] There are several problems with the measurement method
depicted in FIG. 1a. The substrate handler 10 must be still, for
example, so the operator can read the level 26, since the
acceleration of the blade 18 would affect the level 26. Therefore,
the inclination of the blade 18 while the blade is in motion is
unknown. Additionally, the lid 14 must be removed, so the operator
can access the substrate handler 10. Therefore, the processing
system must be shut down, so the lid 14 can be removed, intruding
into the clean environment; and the ambient air must be more highly
filtered of particles than usual, so the interior of the transfer
chamber 12 is not contaminated. Also, the level 26 does not fit
through the slit valve openings 22, so the operator must remove the
level 26 from the blade 18 to extend the blade 18 into a process
chamber and then place the level 26 back onto the blade 18.
Therefore, the process chamber must also be opened, exposing the
process chamber to possible contamination and further increasing
the down-time of the system. Furthermore, the levels used to
measure the inclination typically can resolve the inclination to
within only two or three degrees accuracy, are highly dependent on
the skill of the operator who is reading the level, and can affect
the blade deflection due to the weight of the level, itself.
Therefore, process systems or processes that are particularly
sensitive to misalignment may be adversely affected. Because of the
problems and difficulties with performing this measurement method,
some operators may elect not to make these measurements very
thoroughly or even not to make them at all.
[0012] FIG. 1b shows another prior art method for determining the
inclination of a substrate 20 seated on a substrate handler blade
18 within a processing system. A stationary laser 36 mounts to a
surface 38 in the processing system, typically the floor of the
transfer chamber, and directs a laser beam 40 into the path of the
substrate 20 as the substrate moves through the system in the
direction of arrow A. This method may be performed during normal
processing of substrates in the processing system or just whenever
needed. When the leading edge 42 of the substrate 20 intersects the
laser beam 40, the laser 36 detects the distance to the substrate
20. Then just before the trailing edge 44 moves out of the laser
beam 40, the laser 36 detects the distance to the substrate 20,
again. If the two distances are about the same, then the substrate
20 is aligned with the surface 38 of the processing system in the
particular axis measured. However, this method does not determine
if the substrate 20 is level. Rather, this method determines the
alignment of the substrate 20 relative to the chamber through which
it is being transferred, so the problems with an inclined substrate
20 or blade 18, as described above, may still occur. Additionally,
this method can determine the inclination of the substrate 20 in
only one axis, the direction of movement. Since the laser 36 does
not move, if the operator wants to determine the inclination of the
substrate 20 in a different axis, then one or more other lasers
will have to be mounted in the processing system to determine the
distance to other points on the substrate 20. Furthermore, since
the laser 36 is not moveable, this method determines the
inclination of the substrate 20 at only one location, so if the
operator wants to determine the inclination of the substrate 20 at
a different location, such as at the opposite side of the transfer
chamber, then additional lasers will have to be mounted at that
location. Moreover, since the laser 36 is mounted into the
processing system, removal of the laser 36 is either impossible or
very difficult. Additionally, contaminants may prevent the proper
functioning of the optics. Furthermore, a warped substrate may lead
the laser sensors to incorrectly determine that the blade or
substrate is inclined. Therefore, although this method can be
performed without opening the processing system, this method is
very inflexible.
[0013] During processing, the blade 18 in many processing systems
is constantly moving between areas of high and low temperatures,
such as hot process chambers and cool load lock chambers. The
frequent temperature variations may cause the blade 18 to suffer
"blade wilt," wherein the blade 18 becomes warped due to expansion
and shrinkage resulting from the temperature changes. Thus, over
time, the blade 18 may be warped out of alignment, so the blade 18
may degrade and hold the substrates at an unacceptable inclination.
Other shifting of alignments between the various substrate support
structures, due to the wear or slippage from constant movement
during processing, may also occur. To reestablish confidence in the
alignment of the substrate support structures, the processing
system must have built-in inclination detection systems, such as
the one shown in FIG. 1b, or the operator must stop the processing
system and open it up to diagnose the condition of the support
structures with a method such as the one shown in FIG. 1a. Because
of the down-time associated with the method shown in FIG. 1a, many
operators elect not to perform the method or to wait until the
substrate support structures are severely out of alignment and
potentially damaging the substrates.
[0014] Therefore, a need exists for an apparatus and method for
determining the inclination and alignment of various substrate
handling mechanisms of a processing system, but that is very
flexible, does not intrude into the clean environment of the
processing system, is fast, and provides a very thorough diagnosis
of the system alignments.
SUMMARY OF THE INVENTION
[0015] An embodiment of the present invention may be a sensor
device generally having a support platform and one or more sensors
mounted on the support platform. The sensor senses a condition,
such as direction or inclination or acceleration in one or two
axes, of the sensor device and outputs a signal indicative thereof.
The sensor sends the signal to a conversion circuit, such as an
analog-to-digital converter, for converting the signal into a
digital signal, which is then sent to a transmitter, also mounted
to the support platform, for wireless transmission of the signal to
a receiver mounted on or near the processing system.
[0016] The support platform generally has physical characteristics,
such as size, mass and stiffness, substantially similar to those of
the substrates being processed in the processing system, so the
sensor device can be transferred throughout the processing system
in a manner similar to the manner in which production substrates
are transferred. Thus, the sensor device is conveyed through the
processing system non-intrusively, i.e. without opening the
isolated portions of the system. Also, the sensor device, while
moving through the processing system, detects and transmits the
sensed inclination, orientation or other information.
[0017] The support platform may be a substrate, and the sensor(s)
and other circuits/devices on the support platform may be
micro-machined directly into the material of the substrate to form
a low-profile sensor device having a total mass near the mass of a
production substrate. In an alternative embodiment, a ceramic chip
carrier may be mounted to the support platform, with a die for the
sensor(s) and other circuits/devices formed into the ceramic chip
carrier to provide a fairly light-weight and cost-effective sensor
device. In yet another alternative embodiment, the sensor(s) and
other circuits/devices may be constructed of surface-mount
integrated circuit chips mounted to the support platform to provide
a cost-effective sensor device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] So that the manner in which the above recited features,
advantages and objects of the present invention are attained and
can be understood in detail, a more particular description of the
invention, briefly summarized above, may be had by reference to the
embodiments thereof which are illustrated in the appended
drawings.
[0019] 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.
[0020] FIG. 1a is a perspective view of a prior art sensor device
in a process chamber.
[0021] FIG. 1b is a side view of a prior art sensor system.
[0022] FIG. 2a is a perspective view of a processing system.
[0023] FIG. 2b is a schematic top view of a processing system.
[0024] FIG. 3 is a schematic block diagram of a sensor device.
[0025] FIG. 4 is a perspective view of a sensor device in a
transfer chamber.
[0026] FIG. 5 is a perspective view of a sensor device on a
substrate handler.
[0027] FIG. 6 is a top view of a sensor device on another substrate
handler.
[0028] FIG. 7a is a side view of a sensor device in a process
chamber in a first configuration.
[0029] FIG. 7b is a side view of the sensor device in the process
chamber in a second configuration.
[0030] FIG. 8 is a graph of the velocity of the sensor device
during movement.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0031] FIGS. 2a and 2b show two configurations for an exemplary
processing system 100 of the present invention. The processing
system 100 is typically disposed in a clean environment of a
manufacturing facility. The processing system 100 and an example of
its function will be described in detail below. Generally, the
processing system 100 includes a central transfer chamber 112, one
or more process chambers 114, one or more load lock chambers 118,
one or more expansion or cool-down chambers 119, a platform frame
121, a gas panel 124 and an optional external substrate handling
system 120, referred to herein as the mini-environment. Some of the
processes that a processing system 100 may perform on a substrate,
or wafer, in the process chambers 114 require the use of process
fluids and/or gases, so the process chambers 114 have fluid lines
(not shown) for delivering the process fluids and/or gases to the
process chambers 114 from the gas panel 124. A transfer chamber
substrate handler, or robot, 116 and a mini-environment substrate
handler 128 are disposed in the transfer chamber 112 and
mini-environment 120, respectively, and move substrates 117, 156
through these chambers to and from the various chambers attached
thereto.
[0032] The substrates enter the process system 100 from pod loaders
122 having pods 154 seated thereon containing several substrates
156. Several structures, such as the substrate handlers 116, 128,
chucks, lift pins, load lock indexers and the like, support the
substrates as the substrates are moved through and processed in the
system 100. To prevent damage to or improper processing of the
substrates, the inclination of each of the support structures must
be very closely aligned and leveled, and the movement of the
support structures and substrates must be smooth. To determine the
inclination and movement of the substrates without shutting down
the system 100 for a significant period of time and opening up the
system 100 to expose the interior of the system 100 to potential
contamination, a sensor device 200 (FIG. 3) is entered into the
system 100 from a pod loader 122 and transferred through the system
100 in a manner similar to the manner that the system 100 handles
the substrates, i.e. production substrates, that are to be
processed. The sensor device 200 is an active probe which can be
entered into the system 100 to investigate many aspects or
conditions of the system 100. The sensor device 200 generally
includes a support platform 202 and several electronic devices,
such as an inclinometer 204, an accelerometer 206, a directional
compass 208, an analog to digital (A/D) converter 210, a
transmitter 212, a power source 214 and a switch 216. In addition,
a small processor (not shown) for pre-filtering data may be
incorporated in the circuitry.
[0033] In the illustrated embodiment, the inclinometer 204 mounts
to the support platform and senses the inclination of the sensor
device 200 and, hence, of the substrate handler or other support
structure. The inclinometer 204 receives electrical power from the
power source 214, such as a lithium-ion battery and power
conditioner, and sends signals indicative of the sensed inclination
to the A/D converter 210. In one embodiment, the inclinometer 204
is a two-axis inclinometer for sensing the inclination of the
sensor device 200 in two axes at 90.degree., so the overall
inclination of the sensor device 200 can be determined from a
suitable calculation. After initial assembly of the processing
system 100, the sensor device 200 can be used to adjust the
inclination of each support structure by transferring the sensor
device 200 through the processing system 100 to each support
structure, sensing the inclination of each support structure at the
time that the sensor device 200 is disposed thereon and adjusting
each support structure as described below to align each support
structure. As described in the background, a misalignment between
two support structures can cause particles to be generated or can
result in an uncertain positioning of the substrate when one of the
support structures transfers a substrate to the other support
structure, so proper alignment of the support structures is
essential.
[0034] An exemplary inclinometer 204 includes a cavity partially
filled with a conductive fluid, such as mercury, and an array of
probes disposed vertically in the cavity into the conductive fluid.
As the inclinometer 204 inclines, the probe at one end of the array
will have a greater contact, and less resistance, with the
conductive fluid than will the probe at the opposite end of the
array. The variation in resistances sensed at each of the probes
determines the inclination of the inclinometer 204. Such
inclinometers, having a profile height of about {fraction (1/2)}
inches, are commercially available and can sense an inclination of
up to about thirty to forty degrees. However, the inclinometer 204
needs to be able to sense an angle of only about five to ten
degrees, since the typical processing system 100 can generally be
assembled in such a manner that the inclination of any given
support structure is within this range. Therefore, a suitable
inclinometer 204 may be constructed having a mass and profile
height significantly less than currently available inclinometers.
It is understood that the invention is not limited to the type of
inclinometer described, but rather, contemplates the use of any
suitable inclinometer.
[0035] The accelerometer 206 mounts to the support platform and
senses the acceleration of the sensor device 200 and, hence, of the
substrate handler or other support structure. The accelerometer 206
receives electrical power from the power source 214 and sends
signals indicative of the sensed acceleration to the A/D converter
210. In one embodiment, the accelerometer 206 is a two-axis
accelerometer for sensing the acceleration of the sensor device 200
in two axes, so the overall acceleration of the sensor device 200
can be determined from a suitable calculation. Similar to the
inclinometer 204, the accelerometer 206 senses the acceleration, or
change in motion, of the sensor device 200 while the processing
system 100 transfers the sensor device 200. For best throughput,
the substrate handlers need to be operated at the highest speed
possible, but an acceleration in a particular axis that is too
great for static friction to hold a substrate on a moving support
structure, about 0.2G's or greater, may indicate a potential for
slippage of the substrate on the support structure during movement,
resulting in an uncertain positioning of the substrate, further
resulting in damage to or improper processing of the substrate.
Actual slippage of the sensor device 200 or malfunctioning of a
substrate handler 116, 128 may be determined by the sensor device
200 when the sensed acceleration of the sensor device 200 is not
substantially the same as the anticipated acceleration during a
particular movement, indicating that the sensor device 200 did not
move in the same manner as the substrate handler 116, 128 or the
substrate handler 116, 128 moved in an unanticipated manner, such
as a jerking, irregular movement. FIG. 8 graphically illustrates
such an irregular movement. The graphed curve is velocity plotted
versus time; however, other plots, such as acceleration vs. time or
inclination vs. time, may be used. In regions 800 and 804, the
velocity smoothly increases until it reaches a constant velocity
and then smoothly decreases, but in region 802, an irregular
movement causes a sharp rise, or discontinuity, in the curve,
indicating a problem with the movement of the substrate handler
116, 128. Thus, the sensor device 200 can detect an improper
movement by a substrate handler 116, 128.
[0036] In an alternative embodiment, the inclinometer 204 may
determine the acceleration of the sensor device, instead of by a
separate accelerometer; thereby, reducing the number of devices on
the sensor device 200. The inclinometer 204 described above
includes a fluid in a cavity, so as the inclinometer 204 is
accelerated, the force of acceleration on the fluid will force the
fluid to one end of the cavity; thereby, falsely indicating an
inclination of the sensor device in the direction of acceleration.
A suitable procedure can resolve this false inclination to an
acceleration.
[0037] The directional compass 208 provides the ability of the
sensor device 200 to determine the horizontal angle, or compass
direction, of the sensor device 200 from magnetic north. Thus, as
the substrate handler 116, 128 or other support structure moves the
sensor device through the system 100, the compass direction of the
sensor device 200 can be determined at any point in the trajectory
of the sensor device. The anticipated compass direction of the
sensor device 200 can be compared with the actual compass direction
to confirm proper movement of the sensor device 200. Additionally,
the inclination of the entire system 100 can be determined by
determining the inclination of the sensor device 200 at
corresponding compass direction points as the substrate handler 116
rotates about a 360.degree. angle. With this data, the inclination
of the system 100 can be resolved with a suitable procedure.
[0038] The A/D converter 210 receives the analog signals from each
of the devices 204, 206, 208 and converts the signals into digital
signals, which are then packetized for transmission via the
transmitter 212 to a receiver. Other methods and apparatuses for
transferring the signals from the sensor device 200 will be readily
apparent to a person skilled in the art. Such other methods and
apparatuses may include, but not be limited to, a transmission
system for sending the analog signals to a receiver, so as to save
the weight of the A/D converter 210 on the sensor device 200.
[0039] The transmitter 212 may be any appropriate transmitter
device, such as an optical transmitter or RF based transmitter, for
sending signals the relatively short distance from the interior of
the system 100 to the exterior. Thus, the transmitter 212 may be an
inexpensive low-power transmitter device.
[0040] One or more receivers 218 are mounted on the system 100 to
receive the signals from the transmitter 212 and send the signals
to a controller system for the system 100. The receivers may be
located on the interior of the system 100 and send the signals over
wires through the walls of the system 100. However, to avoid having
to modify the system 100 for wires to pass through the system
walls, it is preferred that the receivers 218 be located on the
exterior of the system 100 at any appropriate aperture, such as at
the viewing ports 220 in the lid of the transfer chamber 112 (FIG.
4), where RF signals can be conveyed out of the system 100 with a
minimum of interference.
[0041] The power source 214 may be any appropriate device, such as
a lithium-ion battery in conjunction with a power conditioner for
obtaining proper working voltages, which is light-weight and
provides sufficient power for sufficient time to conduct all of the
measurements necessary for the system 100. The battery may be
rechargeable for repeated use, or it may be replaceable in a
suitable receptacle. The switch 216 turns the power on and off to
the electronic devices on the sensor device 200.
[0042] It is understood that the invention is not limited to the
sensor device 200 depicted in FIG. 3 and described herein, but
contemplates other configurations of sensor devices or active
probes, including but not limited to the examples described below,
that may be transferred through a processing system and may have
any number of different combinations and types of electronic
devices for sensing conditions within the system 100. For example,
a magnetic probe that includes hall effect magnetic field sensors
may allow magnetic fields to be characterized within the system 100
while the system 100 is closed. Thus, an operator may adjust the
rotation of a magnetron or the current flowing through a variety of
coils in a process chamber to ensure uniformity of magnetic fields
created therein and of a plasma created thereby within the process
chamber while receiving immediate feedback of the actual conditions
of the fields.
[0043] Another type of probe may provide characterization of an
electrostatic chuck, which holds a substrate in place using an
electrostatic charge during processing. This probe may determine
the performance of various charge abatement strategies used to
release the substrate so the substrate may be picked up and removed
by a substrate handler. The probe may also detect dielectric
punch-throughs, a condition in which charge differential between
the electrostatic chuck and the substrate is lost due to discharge
holes in the non-conductive face of the electrostatic chuck. One
embodiment of such an electrostatic probe has a micro machine
and/or circuit on a substrate platform including a diaphragm
element which deflects toward the electrostatic chuck as a function
of charge. The magnitude of this deflection indicates the charge
differential between the probe/substrate and the electrostatic
chuck. The electronic devices on the electrostatic probe must be
fabricated to withstand the environment adjacent the electrostatic
chuck since this environment is usually hostile to active
electronics.
[0044] Yet another probe may be a temperature probe including
temperature sensors to map thermal characteristic of an environment
inside the system 100. Many process chambers and systems 100
operate at very high temperatures, such as above 300.degree. C., so
since most electronics only work up to about 80.degree. C., the
probe may only be used if the system 100 is operated at a lower
temperature. The temperature probe may be used to develop or
validate basic temperature control schemes within the system 100 or
individual process chambers. Additionally, a temperature probe
which can detect a thermal gradient across the length of the probe
may determine uniformity of process gas distribution within a
process chamber since a small gradient indicates that the process
gas has been evenly distributed over the probe. The thermal
gradient probe must account for disruptions in the normal flow of
the process gases due to any structures on the surface probe. For
use in a process chamber having a shower head gas inlet at the top
of the process chamber and which can rotate a substrate for even
processing, such as in some chemical vapor deposition chambers, a
configuration for a temperature probe includes an array of
temperature sensors on the probe platform orientated radially out
from the center thereof with spacing matching the spacing of the
gas apertures of the shower head. As the probe is rotated, it can
detect a change in temperature associated with the gas exiting each
aperture, so clogged apertures may be detected by an unexpected
temperature variation. An embodiment for this example may include
piezoelectric detectors which deflect when subjected to the gas
stream in front of the aperture.
[0045] Another active probe is a distance probe which can ensure
that the wafer surface is both parallel to and at the proper
distance from the target or shower head of the process chamber.
Embodiments of a distance probe may include contacting sensors or
electro-optical sensors arranged at a sufficient number of
locations on the surface of the probe platform to determine the
distance from and angle of inclination between the probe and the
target or shower head. Since the distance probe sits on a chuck in
the process chamber when the distance measurements are performed,
the mass of the probe is not a significant issue, so the weight of
the distance probe may be increased if necessary to reduce the
cost.
[0046] Yet another type of probe may be an optical source detection
probe for detecting a light beam, infrared beam or other optical
signal from a source thereof to determine whether the source is
operating within normal or acceptable limits. Such optical sources
may be part of an optical sensor system within a system 100 for
providing feedback to a system controller regarding the performance
of parts of the system 100, such as a substrate edge detection
sensor system for automatic center finding of substrates being
processed within the system 100. If the optical source detection
probe determines that a source is not operating within acceptable
limits, then the optical source may be defective or the optical
pathway of the optical beam signal from the source may be
contaminated or blocked, so the system 100 may require servicing or
maintenance.
[0047] FIG. 4 shows a sensor device 200 positioned on the substrate
handler 116 inside the transfer chamber 112 with the transfer
chamber lid 240 partially raised. The substrate handler 116 moves
the sensor device 200 back and forth in the directions of arrows A
and B and/or holds the sensor device 200 relatively motionless at
any location inside the transfer chamber 112 while the sensor
device 200 takes the desired measurements and transmits the
information to the receivers 218 positioned on the exterior of the
transfer chamber 112.
[0048] FIGS. 5 and 6 show two different types, single bladed and
double bladed, of substrate handlers 116 for illustrative purposes;
however, both substrate handlers 116 perform the functions of
rotating the sensor device 200 within the transfer chamber 112 and
extending the sensor device 200', as shown by the dashed lines in
FIG. 6. The substrate handler 116 has a blade 244 for holding the
sensor device 200. The blade 244 attaches at a wrist 258 to
articulating arms 254, 256, which attach to actuating arms 246,
248, which attach to upper and lower rotating members 250, 252,
respectively, to rotate back and forth to rotate the sensor device
200 and/or to extend or retract the sensor device 200. Each joint
of the substrate handler 116 must be carefully aligned for the
movement of the sensor device 200 to be proper. In other words, the
blade 244 must be properly attached and aligned to the articulating
arms 254, 256 at the wrist 258, the articulating arms 254, 256 must
be properly aligned with respect to the actuating arms 246, 248,
and the actuating arms 246, 248 must be properly aligned with the
upper and lower rotating members 250, 252 for the inclination of
the blade 244 to be proper. Any misalignment in any of the joints
of the substrate handler 116, or in the alignment between the
substrate handler base 260 and the transfer chamber floor 262, can
cause the blade 244 to be improperly inclined, and the inclination
can be detected by the sensor device 200.
[0049] Mechanical tolerances and mechanical pre-loads in each of
the joints of the substrate handler 116 can make accurate alignment
of the blade 244 extremely difficult. Thus, it is very undesirable
to have to replace and realign the blade 244. However, the blade
244 is subjected to many rapid variations in temperature during
operation of the system 100, so the blade 244 may undergo blade
wilt, or warpage, causing the blade to become inclined or the
attachment points at the wrist 258 to yield. If the blade
inclination or attachment point yield becomes severe, then the
blade 244 or a substrate on the blade 244 may strike an object or
surface in the system 100; thereby breaking or otherwise damaging
the blade 244 or the substrate. In such an event, the system 100
will have to be turned off and opened to repair or replace the
damaged parts, including the blade 244. If the blade 244 is broken,
then the wrist 258 or other parts and joints of the substrate
handler 116 may be compromised or damaged, so each part of the
substrate handler 116 will have to be realigned. To prevent this
damage and downtime, the inclination and alignment of the blade 244
should be confirmed periodically. The sensor device 200 provides a
way to confirm the inclination and alignment of the blade 244 in
all directions without having to turn off and open the system 100;
thereby, permitting detection and replacement of a wilted or
defective blade before severe damage occurs.
[0050] The substrate handler 116 extends, as shown in FIG. 6, to
insert the sensor device 200 through a slit valve opening 242 and
into an attached process chamber (not shown). The height of the
sensor device 200 and all of the electronic devices thereon is such
that the sensor device 200 can easily pass through the slit valve
opening 242 while seated on the blade 244. Thus, the sensor device
200 can determine the inclination at the retracted position,
extended position or any intermediate position without having to
remove the sensor device 200, insert the blade 244 through the slit
valve opening 242, and replace the sensor device 200. The sensor
device 200 can also determine the acceleration during the extension
and retraction of the substrate handler 116.
[0051] The operation of the sensor device 200 with a typical
process chamber will now be described with reference to FIG. 7.
Although FIG. 7 shows a schematic view of a CVD chamber 114, it is
understood that the invention is not so limited, but that the
substrate handler 116 can insert the sensor device 200 through the
slit valve opening 242 into any type of process chamber 114, such
as a PVD chamber, a CVD chamber, an etch chamber, a photo
lithography chamber or other chamber, and that the sensor device
200 may operate with any of these types of process chambers. The
process chamber 114 generally has chamber walls 270, a substrate
lift mechanism 272, a substrate support structure 274 and a chamber
lid 278. The chamber walls 270 and chamber lid 278 generally define
the interior of the process chamber 114. An opening 280 provides
access to the interior of the process chamber 114 and matches up
with the slit valve opening 242 of the transfer chamber 112 for the
substrate handler 116 to insert or remove substrates into or from
the interior of the process chamber 114. A process gas shower head
276 disposed in the chamber lid 278 permits a process gas to enter
through a gas source 282 and be dispersed into a processing region
286 of the interior of the process chamber 114 through shower head
nozzles 284.
[0052] The substrate lift mechanism 272 generally has lift pins 292
for supporting a substrate (not shown) and mounted on an arm 290
which is, in turn, mounted on a lift rod 288 for raising and
lowering the substrate lift mechanism 272. When a substrate is
inserted through the opening 280 into the interior of the process
chamber 114, the lift mechanism 272 lifts the substrate off of the
blade 244 of the substrate handler 116 with the lift pins 292 by
raising the lift rod 288 and arm 290 as depicted in FIG. 7a. The
blade 244 passes between the lift pins 292 when the lift pins 292
support the substrate. The substrate lift mechanism 272 handles the
sensor device 200 in the same manner as it handles a substrate. In
this manner, the sensor device 200 is passed from the substrate
handler 116 to the substrate lift mechanism 272.
[0053] The substrate support structure 274 generally includes a
chuck 294 for supporting a substrate and mounted on a lift rod 296
for raising and lowering the substrate support structure 274. The
substrate support structure 274 also has guide holes 298 for
permitting the lift pins 292 to extend therethrough, as shown in
FIG. 7a, to engage the substrate or sensor device 200. To place the
sensor device 200 onto the chuck 294, the substrate lift mechanism
272 may lower the sensor device 200 to the chuck 294, as shown in
FIG. 7b, or the chuck 294 may raise up to lift the sensor device
200. In this manner, the sensor device 200 is passed from the
substrate lift mechanism 272 to the substrate support structure
274.
[0054] While seated on either the substrate lift mechanism 272 or
the substrate support structure 274, the sensor device 200 can
determine its inclination, just as it could when it was seated on
the substrate handler 116. Both the substrate lift mechanism 272
and the substrate support structure 274 can be individually
adjusted from outside the process chamber 114 by manipulating the
mechanisms (not shown) that support and operate the lift rods 288,
296 to tilt or swivel the lift rods 288, 296, and thereby, change
the inclination of the lift pins 292 or chuck 294, respectively.
Since these manipulations can be done from outside, typically
underneath, the process chamber 114, the sensor device 200 provides
a means to receive feedback regarding the inclination of the
substrate lift mechanism 272 and the substrate support structure
274 without opening the process chamber 114. Thus, these structures
272, 274 can be leveled to correct an improper inclination very
quickly and accurately.
[0055] Additionally, the degree of misalignment between the
substrate handler 116 and the substrate lift mechanism 272 and
between the substrate lift mechanism 272 and the substrate support
structure 274 can be determined from a reading of the inclination
of the sensor device 200 before and after a transfer from one
structure to the other. Thus, the sensor device 200 provides a way
to convey the inclination at exchange points and to align each
structure that supports a substrate with the other such structures
without opening the system 100 and compromising the isolated
environment therein. In a similar manner, even though it is not
shown in the drawings, the indexer cassette lift of the load lock
chambers 118 (FIG. 2) has a mechanism for leveling or aligning the
indexer plate, which supports cassettes and/or substrates within
the load lock chamber 118. The indexer can be aligned with respect
to the substrate handlers 116, 128. A typical alignment procedure
for aligning all of the substrate support structures within a
system 100 may begin with leveling one support structure, such as
whichever support structure is most difficult to adjust, e.g. the
substrate handler 116, and then aligning all other support
structures with respect to the first support structure. In this
manner, alignment throughout the system 100 is assured, so a
substrate is unlikely to be damaged during transfers from one
support structure to another.
[0056] A typical operation of the sensor device 200 will be
described with reference to the exemplary system described
below.
[0057] An Exemplary System:
[0058] Referring back to FIG. 2, a processing system which may use
the above described sensor device 200 to diagnose substrate
handling conditions will now be described. FIG. 2a generally shows
a perspective view of a processing system 100. FIG. 2b generally
shows a schematic top view thereof. Although the function of the
sensor device 200 is described herein with reference to the system
100, it is understood that the invention is not so limited, but
that the sensor device 200 may function with any type of processing
system. As mentioned briefly above, the processing system 100
includes a central transfer chamber 112 as the center of activity
in the handling of wafers, or substrates, through the system 100.
The transfer chamber 112 typically mounts on a platform 121. The
transfer chamber 112 has process chambers 114 attached at facets
113. The process chambers 114 may be any type of process chamber,
such as a physical vapor deposition chamber, a chemical vapor
deposition chamber, an etch chamber, etc. It is not uncommon for a
manufacturer of process chambers to provide over twenty different
types of process chambers. The process chambers 114 may be
supported by the transfer chamber 112, by the platform 121 or on
their own platforms, depending on the configuration of the
individual process chambers 114. Slit valves (not shown) in the
facets 113 provide access and isolation between the transfer
chamber 112 and the process chambers 114. Correspondingly, the
process chambers 114 have openings (not shown) on their surfaces
that align with the slit valves.
[0059] The system 100 includes a gas panel 124 connected to the
process chambers 114 through fluid lines (not shown) for delivering
process fluids to the process chambers 114 or a vaporizer (not
shown). The gas panel 124 connects to a source of the process
fluids in the manufacturing facility, and typically delivers the
process fluids in a gaseous state to the process chambers 114.
[0060] The transfer chamber 112 also has two load lock chambers 118
mounted at facets 115. Openings (not shown) in the facets 115
provide access and isolation between the load lock chambers 118 and
the transfer chamber 112. Correspondingly, the load lock chambers
118 have openings on their surfaces that align with the openings in
facets 115. The load lock chambers 118 are optionally attached to
mini-environment 120. The load lock chambers 118 and the
mini-environment 120 have corresponding openings (not shown)
providing access therebetween, while doors 126 for the openings
provide isolation. The mini-environment 120 has four pod loaders
122 attached on its front side. Openings (not shown) with
corresponding doors 123 provide access and isolation between the
mini-environment 114 and the pod loaders 122. The pod loaders 122
are essentially shelves for supporting pods, or cassettes, 154
containing substrates 156 to be processed in the system 100.
[0061] In operation, the pods 154 containing substrates 156 to be
processed in the system 100 are placed on the top of the pod
loaders 122. However, when the system 100 is to be diagnosed with a
sensor device 200, then a pod containing only the sensor device,
with the switch 216 having been turned on, is placed on one of the
pod loaders 122. Alternatively, if conditions within the system 100
permit, the sensor device 200 may be inserted in a pod containing
production substrates, so the sensor device 200 will be transferred
through the system 100 with almost no interruption to normal
substrate processing. The mini-environment robot 128 removes the
sensor device 200 out of the pod 154 and into one of the load lock
chambers 118. During the entire time that the sensor device 200 is
within the system 100, it is transmitting its data to a receiver
for further transmission to a controller for storage or processing.
Thus, the sensor device 200 begins by transmitting the condition of
the pod 154 on the pod loader 122. When the robot 128 picks up the
sensor device 200, the sensor device 200 can detect any
misalignment between the pod 154 and the robot 128. Afterwards, the
sensor device 200 transmits data diagnosing the movement of the
robot 128 to the load lock chamber 118.
[0062] After the sensor device 200 has been loaded into the load
lock chamber 118, the pressure in the load lock chamber 118 may be
reduced to match that in the transfer chamber 112 and simulate
actual processing conditions, or the transfer chamber 112 may be
pressurized with a purge gas to bring the pressure level of the
transfer chamber 112 to that of the load lock chamber 118. During
this time, the sensor device 200 transmits data diagnosing the
condition of the load lock chamber 118. After the load lock chamber
118 opens to the transfer chamber 112, the substrate handler 116
removes the sensor device 200 from the load lock chamber 118, and
the sensor device 200 can detect any misalignment between the load
lock chamber 118 and the substrate handler 116. If the sensor
device 200 is to diagnose the entire system 100, then the substrate
handler 116 moves the sensor device 200 through a representative
sample of movements in the transfer chamber 112, such as in a
complete circle as well as to each of the process chambers 114,
while the sensor device 200 detects the conditions during movement,
stopping and starting. When the substrate handler 116 moves the
sensor device 200 to one of the process chambers 114, the substrate
support structures, such as the lift pins 292 and chuck 294,
receive the sensor device 200 and move the sensor device 200
through a typical set of movements to which a production substrate
would be subjected. During this time, the sensor device 200 detects
any misalignments between the substrate support structures as well
as any irregular movements or improper inclinations. After the
sensor device 200 is handled in the process chamber 114, the
substrate handler 116 retrieves the sensor device 200 and moves the
sensor device 200 back to one of the load lock chambers 118,
preferably not the same load lock chamber 118 through which the
sensor device 200 entered the system 100, so the other load lock
chamber 118 may be diagnosed, too. Additionally, the substrate
handler 116 may move the sensor device 200 to other types of
chambers or devices, such as a substrate orienter or a cool down
chamber. The load lock chamber 118 may transition the pressure to
that of the mini-environment 120 or ambient environment, while the
sensor device 200 transmits data regarding conditions in the load
lock chamber 118. Afterwards, the substrate handler 128 retrieves
the sensor device 200 and moves the sensor device 200 back to a
wafer pod 154.
[0063] If the controller processes the data from the sensor device
200 while the sensor device 200 is moving through the system 100,
then misalignments, improper inclinations or other irregularities
may be determined almost immediately and corrective action may be
taken by the operator. For example, if a misalignment is detected
between the substrate handler 116 and the lift pins 292 of one of
the process chambers 114, then the operator can adjust the
substrate lift mechanism 272 to correct the misalignment. The
operator can also cause the substrate lift mechanism 272 and
substrate handler 116 to transfer the sensor device 200 back and
forth while the operator makes fine adjustments to the substrate
lift mechanism 272. This entire diagnosis and adjustment procedure
may be conducted at any time and without opening the system 100 to
the external environment.
[0064] While the foregoing is directed to the preferred embodiment
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 which
follow.
* * * * *