U.S. patent application number 10/873568 was filed with the patent office on 2004-11-18 for transfer devices for handling microelectronic workpieces within an environment of a processing machine and methods of manufacturing and using such devices in the processing of microelectronic workpieces.
Invention is credited to Harris, Randy, Woodruff, Daniel J..
Application Number | 20040228719 10/873568 |
Document ID | / |
Family ID | 27559900 |
Filed Date | 2004-11-18 |
United States Patent
Application |
20040228719 |
Kind Code |
A1 |
Woodruff, Daniel J. ; et
al. |
November 18, 2004 |
Transfer devices for handling microelectronic workpieces within an
environment of a processing machine and methods of manufacturing
and using such devices in the processing of microelectronic
workpieces
Abstract
Transfer devices for handling microelectronic workpieces,
apparatus for processing microelectronic workpieces, and methods
for manufacturing and using such transfer devices. One embodiment
of a transfer device includes a transport unit configured to move
along a linear track and a lift assembly carried by the transport
unit. The transfer device can also include an arm assembly having
an arm actuator carried by the lift assembly to move along a lift
path and an arm carried by the arm actuator to rotate about the
lift path. The arm can include a first extension projecting from
one side of the lift path and a second extension projecting from
another side of the lift path. The arm actuator can rotate the arm
about the lift path. The transfer device can also include a first
end-effector and a second end-effector. The first end-effector is
rotatably coupled to the first section of the arm to rotate about a
first rotation axis, and the second end-effector is rotatably
coupled to the second extension of the arm to rotate about a second
rotation axis. The first and second rotation axes can be generally
parallel to the lift path, which itself can be substantially
vertical, and the first and second end-effectors can be at
different elevations relative to the arm.
Inventors: |
Woodruff, Daniel J.;
(Kalispell, MT) ; Harris, Randy; (Kalispell,
MT) |
Correspondence
Address: |
PERKINS COIE LLP
PATENT-SEA
P.O. BOX 1247
SEATTLE
WA
98111-1247
US
|
Family ID: |
27559900 |
Appl. No.: |
10/873568 |
Filed: |
June 22, 2004 |
Related U.S. Patent Documents
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Application
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Filing Date |
Patent Number |
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10873568 |
Jun 22, 2004 |
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09875300 |
Jun 5, 2001 |
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6752584 |
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09875300 |
Jun 5, 2001 |
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08990107 |
Dec 15, 1997 |
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6672820 |
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09875300 |
Jun 5, 2001 |
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09386566 |
Aug 31, 1999 |
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6318951 |
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09386566 |
Aug 31, 1999 |
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PCT/US99/15567 |
Jul 9, 1999 |
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09875300 |
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09386590 |
Aug 31, 1999 |
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6322119 |
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09386590 |
Aug 31, 1999 |
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PCT/US99/15567 |
Jul 9, 1999 |
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09875300 |
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09618707 |
Jul 18, 2000 |
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6654122 |
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09618707 |
Jul 18, 2000 |
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08680056 |
Jul 15, 1996 |
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09875300 |
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08940524 |
Sep 30, 1997 |
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08940524 |
Sep 30, 1997 |
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08680056 |
Jul 15, 1996 |
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Current U.S.
Class: |
414/744.5 |
Current CPC
Class: |
H01L 21/67259 20130101;
B25J 18/02 20130101; H01L 21/67742 20130101; B25J 9/042 20130101;
H01L 21/68707 20130101; Y10T 74/20317 20150115; H01L 21/67781
20130101; B25J 5/02 20130101; H01L 21/67173 20130101; H01L 21/67769
20130101; H01L 21/67766 20130101 |
Class at
Publication: |
414/744.5 |
International
Class: |
B66C 023/00 |
Claims
1-76. (Cancelled)
77. A method for processing a microelectronic workpiece in a
processing apparatus having a first set of processing stations in a
first row and a second set of processing stations in a second row,
the method comprising: holding a first microelectronic workpiece
with a first end-effector rotatably attached to one end of a
cantilevered arm at a rotation axis, the arm having another end
fixedly attached to a waist member that moves linearly along a lift
path and rotates about the lift path; holding a second
microelectronic workpiece with a second end-effector rotatably
attached to the one end of the arm to rotate coaxially about the
rotation axis; and positioning the first microelectronic workpiece
in a first plane at a first distance over the arm and positioning
the second microelectronic workpiece in a plane at a second
distance over the arm.
78. The method of claim 77, further comprising rotating the first
end-effector and/or the second end-effector to position the first
and second microelectronic workpieces over the arm such that at
least a portion of the first microelectronic workpiece is under at
least a portion of the second microelectronic workpiece.
79. The method of claim 77, further comprising rotating the first
end-effector and/or the second end-effector to position the first
and second microelectronic workpieces over the arm such that the
first microelectronic workpiece is superimposed relative to the
second microelectronic workpiece.
80. The method of claim 77, further comprising rotating the arm
relative to a lift path and rotating the first end-effector
relative to a first rotation axis generally parallel to the lift
path to position the first end-effector adjacent to a processing
station in the first set of processing stations.
81. The method of claim 80, further comprising subsequently
rotating the arm relative to the lift path and rotating the first
end-effector relative to the rotation axis to position the first
end-effector adjacent to a processing station in the second set of
processing stations.
82. The method of claim 77, further comprising rotating the first
end-effector through a first plane relative to the arm, rotating
the second end-effector through a second plane relative to the arm,
and rotation the arm to position the first and second end-effectors
relative to the processing stations, wherein the first plane does
not intersect the second plane in a region over the arm.
83. The method of claim 77, further comprising: rotating the first
end-effector and/or the second end-effector to position the first
and second microelectronic workpieces over the arm such that the
first microelectronic workpiece is superimposed relative to the
microelectronic workpiece; and moving the arm along a linear track
between the first and second rows of processing stations, the
movement of the arm moving both the first and second workpieces
together along the track.
84. A transfer device for handling microelectronic workpieces
within an environment of a processing machine, comprising: a
transport unit configured to move along a linear track; a lift
assembly carried by the transport unit; an arm assembly including a
waist member rotatable about a vertical lift axis and operatively
connected to the lift assembly to move linearly along the lift
axis, an arm having a single fixed-length link with a first end
fixedly attached to the waist member and a second end projecting
away from one side of the waist member, and a rotating hub at the
second end of the link defining a rotation axis; a first
end-effector connected to the rotating hub at the second end of the
link to rotate about the rotation axis, and the first end-effector
being spaced apart from the link to rotate in a first plane over
the link; and a second end-effector connected to the rotating hub
at the second end of the link to rotate coaxially about the
rotation axis, and the second end-effector being spaced apart from
the link to rotate in a second plane over the link above the first
plane.
85. The transfer device of claim 84 wherein the first and second
end-effectors can rotate through an arc such that the first
end-effector and the second end-effector can be superimposed with
each other above the link over the lift axis.
86. The transfer device of claim 84 wherein the link comprises a
rigid cantilevered member, and wherein the first and second
end-effectors are carried by the rigid cantilevered member without
an independently pivoting intermediate link between the first and
second end-effectors and the waist member.
87. A transfer device for handling microelectronic workpieces
within an environment of a processing machine, comprising: a base
unit; a lift assembly carried by the unit and having a carriage
moveable along a lift axis; an arm assembly including a waist
member rotatable about the lift axis and connected to the lift
assembly to move linearly along the lift axis, a single lateral
section fixed to the waist member to rotate with the waist member,
and a rotating hub carried by the lateral section to define a
rotation axis, wherein the lateral section projects along a radius
away from a single side of the waist member in a cantilevered
arrangement; a first end-effector connected directly to the
rotating hub to rotate about the rotation axis by a fixed radius in
a first plane spaced apart from the lateral section by a first
distance; and a second end-effector connected directly to the
rotating hub to rotate coaxially about the rotation axis by a fixed
radius in a second plane spaced apart from the lateral section by a
second distance greater than the first distance.
88. The device of claim 87 wherein the base unit comprises a
transport unit having a guide member configured to move along a
linear track.
89. The device of claim 87 wherein the base unit comprises a
rotatable unit.
90. The device of claim 87 wherein the lateral section has a fixed
length without an intermediate link between the lateral section and
the first and second end-effectors.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of: (1) pending
U.S. patent application Ser. No. 08/990,107, entitled "ROBOTS FOR
MICROELECTRONIC WORKPIECE HANDLING," filed on Dec. 15, 1997; (2)
U.S. patent application Ser. No. 09/386,566, filed Aug. 31, 1999,
entitled "IMPROVED ROBOT FOR MICROELECTRONIC WORKPIECE HANDLING,"
which is a continuation of International Patent Application No.
PCT/US99/15567, filed Jul. 9, 1999, designating the U.S., entitled
"ROBOTS FOR MICROELECTRONIC WORKPIECE HANDLING," which application
claims priority from U.S. patent application Ser. No. 09/114,105,
filed Jul. 11, 1998, entitled "ROBOT FOR MICROELECTRONIC WORKPIECE
HANDLING," (3) U.S. patent application Ser. No. 09/386,590, filed
Aug. 31, 1999, entitled "ROBOTS FOR MICROELECTRONIC WORKPIECE
HANDLING," which is a continuation of International Patent
Application No. PCT/US99/15567, filed Jul. 9, 1999, designating the
U.S., entitled "ROBOTS FOR MICROELECTRONIC WORKPIECE HANDLING,"
which application claims priority from U.S. patent application Ser.
No. 09/114,105, filed Jul. 11, 1998, entitled "ROBOT FOR
MICROELECTRONIC WORKPIECE HANDLING," (4) U.S. application Ser. No.
09/618,707 filed Jul. 18, 2000, which is a divisional of U.S.
application Ser. No. 08/680,056 filed Jul. 15, 1996 and now
abandoned; and (5) U.S. application Ser. No. 08/940,524 filed Jul.
30, 1997, which is a continuation-in-part of U.S. application Ser.
No. 08/680,056 filed Jul. 15, 1996; all of which are herein
incorporated by reference. Additionally, this application is
related to the following:
[0002] (a) U.S. Patent Application entitled "INTEGRATED TOOLS WITH
TRANSFER DEVICES FOR HANDLING MICROELECTRONIC WORKPIECES," filed
concurrently, and identified by Perkins Coie LLP Docket No.
291958153US 1;
[0003] (b) U.S. Patent Application entitled "DISTRIBUTED POWER
SUPPLIES FOR MICROELECTRONIC WORKPIECE PROCESSING TOOLS," filed
concurrently, and identified by Perkins Coie LLP Docket No.
291958155US;
[0004] (c) U.S. Patent Application entitled "ADAPTABLE
ELECTROCHEMICAL PROCESSING CHAMBER," filed concurrently, and
identified by Perkins Coie LLP Docket No. 291958156US;
[0005] (d) U.S. Patent Application entitled "LIFT AND ROTATE
ASSEMBLY FOR USE IN A WORKPIECE PROCESSING STATION AND A METHOD OF
ATTACHING THE SAME," filed concurrently, and identified by Perkins
Coie LLP Docket No. 291958154US;
[0006] (e) U.S. Patent Application entitled "APPARATUS AND METHODS
FOR ELECTROCHEMICAL PROCESSING OF MICROELECTRONIC WORKPIECES,"
filed May 31, 2001, and identified by Perkins Coie LLP Docket No.
291958158US;
[0007] (f) U.S. Patent Application entitled "TUNING ELECTRODES USED
IN A REACTOR FOR ELECTROCHEMICALLY PROCESSING A MICROELECTRONIC
WORKPIECE," filed on May 24, 2001, and identified by Perkins Coie
LLP Docket No. 291958157US1.
[0008] All of the foregoing Patent Applications identified by
paragraphs (a)-(f) above are herein incorporated by reference.
TECHNICAL FIELD
[0009] The present invention relates to processing microelectronic
workpieces and handling such workpieces within an environment of a
processing machine.
BACKGROUND
[0010] Microelectronic devices, such as semiconductor devices and
field emission displays, are fabricated on and/or in
microelectronic workpieces using several different apparatus
("tools"). Many such processing apparatus have a single processing
station that performs one or more procedures on the workpieces.
Other processing apparatus have a plurality of processing stations
that perform a series of different procedures on individual
workpieces or batches of workpieces. The workpieces are generally
handled within the processing apparatus by automatic handling
equipment (i.e., robots) because microelectronic fabrication
requires extremely clean environments, very precise positioning of
the workpieces, and conditions that are not suitable for human
access (e.g., vacuum environments, high temperatures, chemicals,
etc.).
[0011] An increasingly important category of processing apparatus
are plating tools that plate metals and other materials onto
workpieces. Existing plating tools use automatic handling equipment
to handle the workpieces because the position, movement and
cleanliness of the workpieces are important parameters for
accurately plating materials onto the workpieces. The plating tools
can be used to plate metals and other materials (e.g., ceramics or
polymers) in the formation of contacts, interconnects and other
components of microelectronic devices. For example, copper plating
tools are used to form copper contacts and interconnects on
semiconductor wafers, field emission displays, read/write heads and
other types of microelectronic workpieces. A typical copper plating
process involves depositing a copper seed layer onto the surface of
the workpiece using chemical vapor deposition (CVD), physical vapor
deposition (PVD), electroless plating processes, or other suitable
methods. After forming the seed layer, copper is plated onto the
workpiece by applying an appropriate electrical field between the
seed layer and an anode in the presence of an electrochemical
plating solution. The workpiece is then cleaned, etched and/or
annealed in subsequent procedures before transferring the workpiece
to another apparatus.
[0012] Single-wafer plating tools generally have a load/unload
station, a number of plating chambers, a number of cleaning
chambers, and a transfer mechanism for moving the microelectronic
workpieces between the various chambers and the load/unload
station. The transfer mechanism can be a rotary system having one
or more robots that rotate about a fixed location in the plating
tool. One existing rotary transfer mechanism is shown in U.S. Pat.
No. 6,136,163 issued to Cheung, et al., which is herein
incorporated by reference in its entirety. Alternate transfer
mechanisms include linear systems that have an elongated track and
a plurality of individual robots that can move independently along
the track. Each of the robots on a linear track can also include
independently operable end-effectors. Existing linear track systems
are shown in U.S. Pat. No. 5,571,325 issued to Ueyama, et al., PCT
Publication No. WO 00/02808, and U.S. patent application Ser. Nos.
09/386,566; 09/386,590; 09/386,568; and 09/759,998, all of which
are herein incorporated in their entirety by reference. Many rotary
and linear transfer mechanisms have a plurality of individual
robots that can each independently access most, if not all, of the
processing stations within an individual tool to increase the
flexibility and throughput of the plating tool.
[0013] The processing tools used in fabricating microelectronic
devices must meet many performance criteria. For example, many
processes must be able to form components that are much smaller
than 0.5 .mu.m, and even on the order of 0.1 .mu.m. The throughput
of these processing tools should also be as high as possible
because they are typically expensive to purchase, operate and
maintain. Moreover, microelectronic processing tools typically
operate in clean rooms that are expensive to construct and
maintain. The throughput, and thus the value of most processing
tools, is evaluated by the number of wafers per hour per square
foot (w/hr/ft.sup.2) that the processing tool can produce with
adequate quality. Therefore, plating tools and many other
processing tools require fast, accurate transfer mechanisms and an
efficient layout of processing chambers to accomplish acceptable
throughputs.
[0014] One concern of existing processing apparatus is that the
wafers may collide with one another as the transfer mechanism
handles the wafers within a tool. Because many processing apparatus
have a plurality of individual robots that move independently from
each other to access many processing chambers within a single
apparatus, the motion of the individual robots must be orchestrated
so that the workpieces do not collide with each other or components
of the tool. This typically requires complex algorithms in the
software for controlling the motion of the workpieces, and the
complexity of the software often necessitates significant processor
capabilities and processing time. The complex algorithms
accordingly increase the cost of the processing tools and reduce
the throughput of workpieces. Additionally, errors in determining
the position of the workpieces, executing the software, or
calibrating the system can result in collisions between workpieces.
Thus, it would be desirable to avoid collisions with workpieces in
a manner that does not adversely impact other parameters of the
processing apparatus.
[0015] Another concern of existing processing apparatus is that the
transfer mechanisms typically have complex mechanical and
electrical assemblies with several components. This increases the
risk that a component may malfunction, causing downtime of the
entire processing machine and/or collisions that damage the
workpieces. Therefore, it would be desirable to reduce the
complexity of the transfer mechanisms.
[0016] Yet another aspect of existing transfer mechanisms is that
they may not provide sufficient freedom of motion of the
workpieces. Although many robots have been developed that have six
degrees of freedom, many of these robots are not used in processing
apparatus for fabricating microelectronic workpieces because the
additional degrees of freedom increase the complexity of the
systems. As a result, many existing transfer mechanisms limit one
or more motions of the robots, such as limiting the vertical motion
of the robots. It will be appreciated that it would be desirable to
maintain the freedom of motion for the robots while also reducing
the probability of collisions between the workpieces and the
complexity of the robots.
SUMMARY
[0017] The present invention is directed toward transfer devices
for handling microelectronic workpieces, apparatus for processing
microelectronic workpieces, and methods for manufacturing and using
such devices. Several embodiments of integrated tools comprise a
single robot, dual end-effector transfer device that is expected to
increase the flexibility of designing integrated tools. By using a
single robot, less space is needed within the cabinet for the
robot. As a result, more space can be used for the processing
chambers so that larger processing chambers can be used in the same
or very similar foot print as smaller chambers. This is useful as
many device fabricators transition from using 200 mm wafers to 300
mm wafer because 300 mm tools can be used in approximately the same
area as 200 mm tools, and the 300 mm tools can have the same number
of processing chambers as the 200 mm tools. Thus, several
embodiments of single robots with dual end-effectors in accordance
with the invention allow designers to more easily replace 200 mm
tools with 300 mm tools.
[0018] Another feature is that each of the end-effectors of the
single robot can service processing chambers in either row inside
tool. The integrated tools can accordingly have several different
configurations of processing chambers that can be assembled on a
"custom basis." The processing chambers can have a common
configuration so that different types of processing chambers can be
mounted to the tool within the cabinet. By providing a robot with
two end-effectors that have a significant range of motion, each
end-effector can access any of the processing chambers so that the
configuration of the processing chambers in the tool is not limited
by the motion of the robot and/or the end-effectors. Therefore, the
processing chambers can be arranged in a configuration that affords
an efficient movement of workpieces through the tool to enhance the
throughput.
[0019] The throughput of finished workpieces is also expected to be
enhanced because the workpieces cannot collide with each other or
another robot in the tool when a single robot with dual
end-effectors is used. The robot can accordingly be a high-speed
device that moves quickly to reduce the time that each workpiece
rests on an end-effector. Additionally, the robot can move quickly
because it does not need complex collision-avoidance software that
takes time to process and is subject to errors. The single robot
can accordingly service the processing stations as quickly as a
dual robot system with single end-effectors on each robot. In
several embodiments of the invention, therefore, the combination of
having a fast, versatile robot and a flexible, efficient
arrangement of processing stations provides a high throughput
(w/hr/ft.sup.2) of finished workpieces.
[0020] In an aspect of one embodiment, a transfer device can
include a transport unit configured to move along a linear track
and an arm assembly operatively coupled to the transport unit. For
example, the transfer device can further include a lift assembly
carried by the transport unit, and the arm assembly can be coupled
to the lift assembly. The arm assembly can include an arm actuator
carried by the lift assembly to move along a lift path and an arm
carried by the arm actuator to rotate about the lift path. The arm
can include a first extension projecting from one side of the lift
path and a second extension projecting from another side of the
lift path. The arm actuator can rotate the arm about the lift path
to position the first and second extensions relative to processing
stations of an apparatus. The transfer device can also include a
first end-effector and a second end-effector. The first
end-effector is rotatably coupled to the first extension of the arm
to rotate about a first rotation axis, and the second end-effector
is rotatably coupled to the second extension of the arm to rotate
about a second rotation axis. The first and second rotation axes
can be generally parallel to the lift path, which itself can be
substantially oblique or normal to the track.
[0021] The arm can include a medial section coupled to the lift
actuator. The first extension can project from one side of the
medial section, and the second extension can project from another
side of the medial section. The first and second extensions can be
integral with one another or they can be separate sections that are
fixedly attached to each other. As a result, the transfer device
can include a single arm with two extensions such that rotation of
the arm causes both of the extensions to rotate about a single
axis. In still another embodiment, the first end-effector is spaced
above the arm by a first distance, and the second end-effector is
spaced above the arm by a second distance. The first distance is
different than the second distance to space the first end-effector
at a different elevation than the second end-effector. The
different spacing of the first and second end-effectors relative to
the arm allows the device to carry two workpieces in a superimposed
relationship without the potential of a collision between the
workpieces. Several additional embodiments and alternate
embodiments of devices, systems and methods are also included in
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is an isometric view of a processing apparatus for
processing microelectronic workpieces including a transfer device
for handling the workpieces in accordance with an embodiment of the
invention. A portion of the processing apparatus is shown in a
cut-away illustration.
[0023] FIGS. 2A and 2B are isometric views of transfer devices for
handling microelectronic workpieces in accordance with embodiments
of the invention.
[0024] FIG. 3A is a top plan view of a processing apparatus for
processing microelectronic workpieces showing one configuration for
operating a transfer device in accordance with an embodiment of the
invention.
[0025] FIG. 3B is a partial isometric view of the transfer device
of FIG. 3A showing another configuration for operating the transfer
device.
[0026] FIG. 3C is a top plan view of the transfer device of FIGS.
3A and 3B showing another configuration for operating the transfer
device.
[0027] FIG. 4 is an isometric view of a transfer device for
handling microelectronic workpieces in accordance with an
embodiment of the invention in which selected components are shown
in cross section and other components are shown schematically.
[0028] FIG. 5 is a cross-sectional view of the transfer device of
FIG. 4.
[0029] FIG. 6 is a cross-sectional view of an end-effector of the
transfer device of FIG. 4.
DETAILED DESCRIPTION
[0030] The following description discloses the details and features
of several embodiments of transfer devices for handling
microelectronic workpieces, processing apparatus for processing
microelectronic workpieces, and methods for making and using such
devices. The term "microelectronic workpiece" is used throughout to
include a workpiece formed from a substrate upon which and/or in
which microelectronic circuits or components, data storage elements
or layers, and/or micro-mechanical elements are fabricated. It will
be appreciated that several of the details set forth below are
provided to describe the following embodiments in a manner
sufficient to enable a person skilled in the art to make and use
the disclosed embodiments. Several of the details and advantages
described below, however, may not be necessary to practice certain
embodiments of the invention. Additionally, the invention can also
include additional embodiments that are within the scope of the
claims, but are not described in detail with respect to FIGS.
1-6.
[0031] The operation and features of the transfer devices for
handling microelectronic workpieces are best understood in light of
the environment and equipment in which they can be used. As such,
several embodiments of processing apparatus in which the transfer
devices can be used will be described with reference to FIG. 1. The
details and features of several embodiments of transfer devices
will then be described with reference to FIGS. 2-7.
[0032] A. Selected Embodiments of Microelectronic Workpiece
Processing Apparatus for Use with Automatic Workpiece Transfer
Devices
[0033] FIG. 1 is an isometric view of a processing apparatus 100
having a workpiece handling device 130 in accordance with an
embodiment of the invention for manipulating a plurality of
microelectronic workpieces 101. A portion of the processing
apparatus 100 is shown in a cut-away view to illustrate selected
internal components. In one aspect of this embodiment, the
processing apparatus 100 can include a cabinet 102 having an
interior region 104 defining an enclosure that is at least
partially isolated from an exterior region 105. The cabinet 102 can
also include a plurality of apertures 106 through which the
workpieces 101 can ingress and egress between the interior region
104 and a load/unload station 110.
[0034] The load/unload station 110 can have two container supports
112 that are each housed in a protective shroud 113. The container
supports 112 are configured to position workpiece containers 114
relative to the apertures 106 in the cabinet 102. The workpiece
containers 114 can each house a plurality of microelectronic
workpieces 101 in a "mini" clean environment for carrying a
plurality of workpieces through other environments that are not at
clean room standards. Each of the workpiece containers 114 is
accessible from the interior region 104 of the cabinet 102 through
the apertures 106.
[0035] The processing apparatus 100 can also include a plurality of
processing stations 120 and a transfer device 130 in the interior
region 104 of the cabinet 102. The processing apparatus, for
example, can be a plating tool, and the processing stations 120 can
be single-wafer chambers for electroplating, electroless plating,
annealing, cleaning, etching, and/or metrology analysis. Suitable
processing stations 120 for use in the processing apparatus 100 are
disclosed in U.S. Pat. Nos. 6,228,232 and 6,080,691, and in U.S.
application Ser. Nos. 09/385,784; 09/386,803; 09/386,610;
09/386,197; 09/501,002; 09/733,608; 09/804,696; and 09/804,697, all
of which are herein incorporated in their entirety by reference.
The processing stations 120 are not limited to plating devices, and
thus the processing apparatus 100 can be another type of tool.
[0036] The transfer device 130 moves the microelectronic workpieces
101 between the workpiece containers 114 and the processing
stations 120. The transfer device 130 includes a linear track 132
extending in a lengthwise direction of the interior region 104
between the processing stations 120. In the particular embodiment
shown in FIG. 1, a first set of processing stations 120 is arranged
along a first row R.sub.1-R.sub.1 and a second set of processing
stations 120 is arranged along a second row R.sub.2--R.sub.2. The
linear track 130 extends between the first and second rows of
processing stations 120. The transfer device 130 can further
include a robot unit 134 carried by the track 132. As explained in
more detail below, the combination of the linear transfer device
130 and the arrangement of the processing stations 120 provides a
good throughput rate of microelectronic workpieces and inhibits
collisions between workpieces that are carried by the robot unit
134.
[0037] B. Embodiments of Transfer Devices for Handling
Microelectronic Workpieces in Processing Machines
[0038] FIG. 2A illustrates an embodiment of the robot unit 134 in
greater detail. The robot unit 134 can include a transport unit
210, an arm assembly 230 carried by the transport unit 210, and
first and second end-effectors 250 (identified individually by
reference numbers 250a and 250b) carried by the arm assembly 230.
The transport unit 210 can include a shroud or housing 212 having a
plurality of panels attached to an internal frame (not shown in
FIG. 2A). An opening 214 in a top panel of the housing 212 receives
a portion of the arm assembly 230. It will be appreciated that the
transport unit 210 and the housing 212 can have many different
configurations depending upon the particular environment in which
the robot unit 134 is used. The transport unit 210, for example,
can be a base that can be stationary, rotary, or move in a
non-linear manner. The transport unit 210 can also include a guide
member configured to move laterally along the track 132. The
particular embodiment of the transport unit 210 shown in FIG. 2A
includes a guide member defined by a base plate 216 that slidably
couples the robot unit 134 to the track 132. The robot unit 134 can
accordingly translate along the track 132 (arrow T) to position the
robot unit 134 adjacent to a desired processing station 120 (FIG.
1).
[0039] The arm assembly 230 can include a waist member 232 that is
coupled to a lift assembly (not shown in FIG. 2A). The arm assembly
230 can also include an arm 234 having a medial section 235, a
first extension 236a projecting from one side of the medial section
235, and a second extension 236b extending from another side of the
medial section 235. The first and second extensions 236a-b of the
arm 234 can be diametrically opposed to one another as shown in
FIG. 2A, or they can extend at a desired angle to each other. In
one embodiment, the first and second extensions 236a and 236b are
integral with another, but in alternate embodiments the first and
second extensions 236a and 236b can be individual components that
are fixed to each other.
[0040] The arm assembly 230 can move along a lift path L-L to
change the elevation of the arm 234 for positioning the
end-effectors 250 at desired elevations. The lift path L-L
generally extends transverse to the track 132, which as used herein
includes any oblique or perpendicular arrangement. The arm assembly
230 can also rotate (arrow R.sub.1) about the lift path L-L to
position a distal end 238a of the first extension 236a and/or a
distal end 238b of the second extension 236b proximate to a desired
workpiece container 114 or processing station 120. The first and
second extensions 236a-b generally rotate about the lift path L-L
as a single unit because they are integral or fixed with each
other. The motion of the first and second extensions 236a-b are
accordingly dependent upon each other in this embodiment. In
alternate embodiments, the arm 234 can have extensions that are not
fixed to each other and can move independently from each other.
Selected embodiments of lift assemblies for moving the arm assembly
230 along the lift path L-L and other assemblies for rotating the
arm 234 about the lift path are described in more detail below with
reference to FIGS. 4 and 5.
[0041] The end-effectors 250 are rotatably carried by the arm 234.
In one embodiment, the first end-effector 250a is rotatably coupled
to the first distal end 238a to rotate about a first rotation axis
A.sub.1-A.sub.1 (arrow R.sub.2). The second end-effector 250b can
be rotatably coupled to the second distal end 238b of the arm 234
to rotate about a second rotation axis A.sub.2-A.sub.2 (arrow
R.sub.3). The first and second rotation axes A.sub.1-A.sub.1 and
A.sub.2-A.sub.2 can extend generally parallel to the lift path L-L,
but in alternate embodiments these axes can extend transverse to
the lift path L-L. The end-effectors 250a-b can each include a
workpiece holder 252 for holding the workpieces 101 to the
end-effectors 250. The workpiece holders 252 shown in FIG. 2A are
vacuum chucks that hold the workpieces 101 to the end-effectors 250
using suction. Alternate embodiments of workpiece holders 252 can
include edge-grip end-effectors, such as those disclosed in the
foregoing patent applications that have been incorporated by
reference. As explained in more detail below with reference to
FIGS. 3A-3C, the rotational motion of (a) the arm 234 about the
lift path L-L, (b) the first end-effector 250a about the first
rotation axis A.sub.1-A.sub.1, and (c) the second end-effector 250b
about the second rotation axis A.sub.2-A.sub.2 can be coordinated
so that the first and second end-effectors 250a and 250b can each
be positioned adjacent to any of the workpiece containers 114 and
processing stations 120 on either side of the cabinet 102 (FIG.
1).
[0042] The first end-effector 250a can be spaced apart from the arm
234 by a first distance D.sub.1, and the second end-effector 250b
can be spaced apart from the arm 234 by a second distance D.sub.2.
In the embodiment shown in FIG. 2A, the distance D.sub.1 is less
than the distance D.sub.2 such that the first end-effector 250a is
at a different elevation than the second end-effector 250b. The
first end-effector 250a accordingly moves through a first plane as
it rotates about the first rotation axis A.sub.1-A.sub.1, and the
second end-effector 250b moves through a second plane as it rotates
about the second rotation axis A.sub.2-A.sub.2. The first and
second planes are generally parallel and fixedly spaced apart from
each other so that the end-effectors 250a-b cannot interfere with
each other. The first and second planes, however, can have other
arrangements (i.e., nonparallel) so long as they do not intersect
in a region over the arm 234. The first and second end-effectors
250a and 250b can be fixed at the particular elevations relative to
the arm 234 using spacers or other types of devices. For example,
the first end-effector 250a can be spaced apart from the arm 234 by
a first spacer 254a, and the second end-effector 250b can be spaced
apart from the arm 234 by a second spacer 254b. The first and
second spacers 254a-b can have different thicknesses to space the
end-effectors 250 apart from the arm 234 by the desired
distances.
[0043] The first and second end-effectors 250a-b and the arm 234
can have different configurations than the configuration shown in
FIG. 2A. For example, as shown in FIG. 2B, the arm 234 can have
only a single extension 236 projecting from the waist member 232
and both of the end-effectors 250a-b can be carried by the
"single-extension" arm such that the first and second end-effectors
250a-b are fixed at different elevations relative to the arm 234.
The end-effectors 250a-b, for example, can be coupled to the end
238 of the arm and rotate about a common rotation axis A-A.
[0044] FIGS. 3A-3C illustrate an arrangement of processing stations
120 and several configurations of operating the transfer device 130
in greater detail. The processing stations 120 can include any
combination or single type of single-wafer units including (a)
clean/etch capsules 120a, such as the CAPSULE.TM. manufactured by
Semitool, Inc.; (b) electroless plating chambers 120b; (c)
electroplating chambers 120c; (d) Rapid Thermal Annealing (RTA)
chambers 120d; (e) metrology stations (not shown in FIG. 3A);
and/or other types of single-wafer processing stations. In the
particular embodiment shown in FIG. 3A, the first row R.sub.1 of
processing stations 120 includes a plurality of clean/etch capsules
120a proximate to the load/unload station 110, an electroless
plating chamber 120b downstream from the clean/etch capsules 120a,
and a plurality of electroplating chambers 120c downstream from the
electroless plating chamber 120b. The second row R.sub.2 of
processing stations of this particular embodiment has a similar
arrangement, except that an RTA chamber 120d is at the output side
of the load/unload station 110 and there is not an electroless
chamber between the clean/etch capsule 120a and the electroplating
chambers 120c.
[0045] The arrangement of processing stations illustrated in FIG.
3A represents only one example of how the processing stations 120
can be arranged within the cabinet 102. In alternate embodiments a
metrology station can be substituted for one or more of the other
processing stations, the position of the processing stations
relative to the load/unload station 110 can be changed, and/or
other types of processing stations can be used such that some of
the processing stations illustrated in FIG. 3A may not be included
in the processing apparatus 100. For example, the position of the
clean/etch capsules 120a and the electroplating chambers 120c can
be switched, or additional electroplating chambers 120c can be
substituted for the electroless chamber 120b and the RTA chamber
120d.
[0046] FIG. 3A illustrates one configuration of operating the
transfer device 130 after a first workpiece 101a has been loaded
onto the first end-effector 250a. The operation of the first
end-effector 250a can be similar to that of the second end-effector
250b, and thus only the movement of the second end-effector 250b
will be described below for purposes of brevity. The robot unit 134
can move the arm assembly 230 (FIG. 2A) so that the second
end-effector 250b can pick up a second workpiece 101b from a
workpiece container 114. To do this the robot unit 134 positions
the first workpiece 101a in a transport position over the lift path
L-L, and then the arm assembly 230 (FIG. 2A) moves vertically until
the second end-effector 250b is at a desired height to pass
underneath the second workpiece 101b. The arm assembly 230 then
rotates the second extension 236b about the lift path L-L (FIG. 2A)
and/or the second end-effector 250b rotates about the second
rotation axis A.sub.2-A.sub.2 (FIG. 2A) until the second
end-effector 250b is under the second workpiece 101b. The arm
assembly 230 can then be raised as a vacuum is drawn through the
workpiece holder 252 (FIG. 2A) to securely hold the second
workpiece 101b to the second end-effector 250b. The robot unit 134
then extracts the second workpiece 101b from the workpiece
container 114 by a combination of movements of the robot unit 134
along the track 132, rotation of the second extension 236b about
the lift path L-L, and/or rotation of the second end-effector 250b
about the second rotation axis A.sub.2-A.sub.2. The remaining
workpieces in the container 114 can be loaded onto the
end-effectors 250 in subsequent processing in a similar manner by
further adjusting the height of either the workpiece container 114
and/or the arm assembly 230 (FIG. 2A) or they can be unloaded into
the other container 114 by reversing this procedure. In general, it
is more desirable to move the arm assembly to the correct height
than it is to move the workpiece container 114 because this
eliminates the need to precisely index all of the workpieces each
time. After picking up the workpieces 101, the transfer device 130
can load or unload any of the workpieces 101 carried by the robot
unit 134 in any of the processing stations 120 in either the first
row R.sub.1 or the second row R.sub.2. The flow of the workpieces
through the processing stations 120 varies according to the
particular application and use of the processing apparatus 100. In
one embodiment, the transfer device 130 can restrict one of the
end-effectors to handle only clean workpieces and the other
end-effector to handle only dirty workpieces. The clean
end-effector can be used to handle the workpieces in the workpiece
containers and to remove the workpieces from the clean/etch
capsules 120a. The dirty end-effector can be used to remove
workpieces from the plating chambers 120b and 120c and then input
the dirty workpieces into the clean/etch capsules 120a.
[0047] One particular process flow for plating copper or other
materials onto the second workpiece 110b involves placing the
second workpiece 101b in either (a) the electroless plating chamber
120b if the seed layer needs to be enhanced or (b) one of the
electroplating chambers 120c. After the workpiece 101b has been
plated, the transfer device 130 extracts the workpiece 101b from
the corresponding electroplating chamber 120c and typically places
it in a clean/etch chamber 120a. The second workpiece 101b can then
be withdrawn from the clean/etch capsule 120a and placed in the
other workpiece container 114 for finished workpieces (the
"out-WIP"). It will be appreciated that this process flow is merely
one example of potential process flows, and that the movement of
the workpieces through the processing stations 120 varies according
to the particular configuration of the processing apparatus and the
processes being performed on the workpieces. For example, the
workpiece 101b can be transferred to the annealing chamber 120d
after the clean/etch chamber 120a before it is placed in the
out-WIP.
[0048] FIG. 3B illustrates another configuration of operating the
transfer device 130 in which the workpieces 101a-b are positioned
for being moved along the track 130. The second workpiece 101b is
superimposed over the first workpiece 101a by rotating the first
end-effector 250a about the first rotation axis A.sub.1-A.sub.1 and
rotating the second end-effector 250b about the second rotation
axis A.sub.2-A.sub.2 until both end-effectors are over the arm. The
arm 234 also rotates about the lift path L-L so that the arm 234
and the first and second extensions 236a and 236b extend generally
in the direction of the track 132. The robot unit 134 can then
translate along the track 132 between the processing stations
120.
[0049] The configuration illustrated in FIG. 3B is particularly
useful in 300 mm applications to reduce the overall width of the
processing apparatus 100. It is desirable to minimize the area of
the floor space occupied by each processing apparatus, but many
designs for accommodating 300 mm wafers tend to occupy much larger
areas than those for use with 200 mm wafers because the processing
stations and the area between the processing stations must be able
to accommodate the larger wafers. By superimposing the workpieces
over one another for transport along the track 132, the open area
used for transporting the workpieces between the rows of processing
stations can be reduced to approximately the diameter of a single
workpiece. Additionally, the same configuration can be used for
handling 200 mm wafers such that the area of floor space occupied
by a 300 mm tool is not significantly more, if any, than a 200 mm
tool. After the workpieces 101a-b are superimposed for movement
along the track 132, the robot unit 134 can move along the track to
a desired processing station and the arm assembly 230 can move
vertically along the lift path L-L to position the workpieces at
desired elevations.
[0050] FIG. 3C illustrates another configuration of operating the
transfer device 130 in which the robot unit 134 is loading the
second workpiece 101b into one of the electroplating chambers 120c.
The robot unit 134 slides along the track 132 until the second
extension 236b of the arm 234 (FIG. 3B) is proximate to the desired
electroplating station 120c. The arm 234 then rotates about the
lift path L-L and the second end-effector 250b rotates about the
second rotation axis A.sub.2-A.sub.2 until the second workpiece
101b is positioned over an inverted head of the electroplating
station 120c. The robot unit 134 can accordingly position each of
the end-effectors 250a and 250b on the desired side of the cabinet
102 and at a desired height so that the end-effectors 250a and 250b
can each access any of the processing stations 120 in either the
first row R.sub.1 or the second row R.sub.2. The transfer device
130 accordingly provides a single-robot having a single arm and
dual end-effectors that can service any of the workpiece containers
114 and/or processing modules 120 within the cabinet 102.
[0051] Several embodiments of the transfer device 130 are expected
to prevent collisions with the workpieces 101 without complex
software algorithms or complex mechanical systems. An aspect of
these embodiments of the transfer device 130 is that they have only
a single arm and the end-effectors are coupled to the single arm so
that the first end-effector operates in a first plane and the
second end-effector operates in a second plane that does not
intersect the first plane over the arm. The first and second
end-effectors can be mechanically spaced apart from each other to
operate in different planes by rotatable spacers that space the
first and second end-effectors apart from the arm by first and
second distances, respectively, irrespective of the elevation of
the arm itself. The end-effectors are thus arranged so that they
can rotate freely relative to the arm but the workpieces cannot
collide with each other. Therefore, the embodiments of the transfer
device 130 that have a single arm with end-effectors coupled to the
arm at different elevations are expected to mitigate collisions
between the workpieces.
[0052] Several embodiments of the transfer device 130 are also
versatile and can be used in many different tools because the
end-effectors have a significant freedom of movement. An aspect of
an embodiment of the transfer device 130 is that the arm can (a)
translate along a track through the machine, (b) move transversely
to the track along a lift path to change the elevation of the
end-effectors, and (c) rotate about the lift-path. This allows the
arm to position the end-effectors at a number of locations and
elevations within the tool so that the tool can have several
different types and arrangements of processing stations serviced by
a single robot. Another aspect is that the end-effectors can be
located at opposite ends of the arm, and they can independently
rotate about the arm. This allows each end-effector to service any
of the processing stations within the tool. Thus, several
embodiments of the transfer device 130 provide the benefits of
having two independently operable end-effectors in a single robot
unit without the complex mechanical components and software
required for systems with two separate robot units.
[0053] Many of the embodiments of the transfer device 130 also
provide a high throughput of finished wafers. The throughput of a
machine used to fabricate microelectronic devices is typically
measured by the w/hr/ft.sup.2 processed through the machine. One
aspect of providing a high throughput is that the linear track
allows several processing stations to be arranged in rows which are
serviced by a single robot. The linear arrangement of processing
stations and the linear-track transfer device significantly
decrease the floor space required for each processing station
compared to systems that use a rotary robot system. Moreover, by
transferring the workpieces along the track in a superimposed
arrangement, the distance between the rows of processing stations
can be reduced to approximately a single wafer diameter. This is
particularly useful in 300 mm applications because carrying these
workpieces side-by-side along a track would require a significant
increase in the foot print of the processing tool. Another aspect
of providing a high throughput is that the single-arm, dual
end-effector robot can operate quickly to access all, or at least
most, of the processing stations in the tool because (a) it does
not need to have complex collision avoidance algorithms that slow
down processing time, and (b) it can use high-speed motors for a
high operating speed. The combination of maintaining a fast,
versatile robot unit and an arrangement that provides an efficient
foot print accordingly provides a high throughput (w/hr/ft.sup.2)
for several embodiments of the processing apparatus 100.
[0054] FIG. 4 illustrates one embodiment of the robot unit 134 in
greater detail. In this particular embodiment, the transport unit
210 and the arm assembly 230 can operate in a manner similar to
that described above with reference to FIGS. 1-3C, and thus like
reference numbers refer to like components in FIGS. 1-4. The robot
unit 134 can include a lift assembly 410 having a lift actuator
412, a lift member 414, and a lift platform 416 coupled to the lift
member 414. The lift actuator 412 can be a servomotor, a linear
actuator, or another suitable device that can provide precise
control of rotational or linear motion. In the embodiment shown in
FIG. 4, lift actuator 412 is a servomotor having a driveshaft 418
to which a drive pulley 419 is attached. The lift member 414 in
this embodiment is a ball screw or a lead screw having a lower end
securely connected to a passive pulley 420. The lift assembly 410
can also include a guide, such as a guide rail 414a. The output
from the lift actuator 412 is coupled to the passive pulley 420 by
a belt 422 around the drive pulley 419 and the passive pulley 420.
The lift assembly 410 can further include a nut 424 that is
threadedly coupled to the lead-screw lift member 414 and fixedly
coupled to the lift platform 416.
[0055] The lift assembly 410 operates to raise/lower the lift
platform 416 by energizing the lift actuator 412 to rotate the
drive pulley 419 and produce a corresponding rotation of the
lead-screw lift member 414. The nut 424 moves vertically according
to the rotation of the lift member 414 to raise/lower the lift
platform 416 for adjusting the elevation of the first and second
end-effectors 250a and 250b. It will be appreciated that the stroke
length of the nut 424 defines the extent of the lift motion of the
arm assembly 230. Additionally, when the nut 424 is positioned at
the lower end of the lift member 414, the lift actuator 412 is
received in a cavity 426 in the lift platform 416. The cavity 426
allows the size of the robot unit 134 to be relatively compact and
the length of the lift stroke to be relatively large because the
lift actuator 412 can be positioned directly under the lift
platform 416.
[0056] It will be appreciated that other embodiments of lift
assemblies can be used to raise and lower the arm assembly 230. For
example, the lift member can be a scissor lift assembly driven by a
servomotor, or the driveshaft of the lift actuator 412 can be the
lead-screw lift member 414 to eliminate the pulleys and belts of
the embodiment of FIG. 4.
[0057] The arm assembly 230 is carried by the lift assembly 410 to
move along the lift path L-L. In the embodiment shown in FIG. 4,
the arm assembly 230 includes a base 430 carried by the lift
platform 416 and a waist motor 432 carried by the base 430. The
waist member 232 is coupled to an output shaft 436 of the waist
motor 432 by a boss 437. The waist motor 432 is fixedly attached to
the base 430, and a rim 438 is fixedly attached to the base 430 to
generally enclose the boss 437. The waist member 232 is fixedly
attached to the boss 437 such that rotation of the boss 437 rotates
the waist member 232. A bearing 440 between the boss 437 and the
rim 438 allows the waist motor 432 to rotate the boss 437 and the
waist member 232 via the output of the driveshaft 436.
[0058] The arm assembly 230 can further include a first
effector-drive 442a and a second effector-drive 442b carried in a
cavity 443 of the waist member 232. The first effector-drive 442a
has an output shaft coupled to a drive pulley 444a, which is
coupled to a passive pulley 445a by a belt 446a. The second
effector-drive 442b can be operatively coupled to the second
end-effector 250b by a similar arrangement. The second
effector-drive 442b, for example, can have an output shaft
connected to a drive pulley 444b, which is coupled to a passive
pulley 445b by a belt 446b. In the embodiment shown in FIG. 4, the
first and second effector-drives 442a and 442b are servomotors.
Alternate embodiments of the arm assembly 230, however, can use
linear actuators housed in the arm 234 or other types of actuators
to manipulate the end-effectors 250a and 250b. For example, the
effector-drives 442 can be servomotors that have output shafts with
a worm gear, and the passive pulleys 445 could be replaced with
gears that mesh with the worm gears. The rotation of the worm gears
would accordingly rotate the end-effectors about the rotation
axes.
[0059] The arm assembly 230 operates by (a) rotating the waist
member 232 and the arm 234 about the lift path L-L, and (b)
independently rotating the first and second end-effectors 250a and
250b about the first and second rotation axes A.sub.1-A.sub.1 and
A.sub.2-A.sub.2, respectively. The waist motor 432 rotates the
waist member 232 and the arm 234 about the lift path L-L to
position the first and second extensions 236a and 236b of the arm
234 at desired locations relative to the workpiece containers 114
(FIG. 1) and/or the processing stations 120 (FIG. 1). The first
effector-drive 442a rotates the first end-effector 250a about the
first rotation axis A.sub.1-A.sub.1, and the second effector-drive
442b rotates the second end-effector 250b about the second rotation
axis A.sub.2-A.sub.2. The effector-drives 442a-b operate
independently from each other and the waist motor 432 so that the
end-effectors 250a and 250b can move in a compound motion with the
arm 234. This motion can thus translate the workpieces 101 along
virtually any desired path. Therefore, the waist motor 432 and the
end-drives 442a-b can operate serially or in parallel to provide
the desired motion of the end-effectors 250.
[0060] The robot unit 134 can also include a plurality of
amplifiers to operate the motors carried by the robot unit 134. In
this embodiment, the amplifiers can include four servoamplifiers
450 (identified by reference numbers 450a-d). The amplifiers 450
operate the lift actuator 412, the waist motor 432, and the
effector-drives 442a-b. Additionally, the transport unit 134 can
include a servoamplifier 452 for a rail motor (not shown) that
moves the transport unit 210 along the track 132 (FIG. 1). The
amplifiers 450 and 452 are controlled by a control circuit board
(not shown in FIG. 4) that is carried by the transport unit 210
such that much of the wiring and the electronics for the robot unit
134 are carried locally with the transport unit 210. Some of the
internal wiring for the waist motor 432 and the effector-drives
442a-b is carried in a flexible cable track 454 that moves
vertically with the lift platform 416. This reduces the number of
long wires running through the processing apparatus 100.
[0061] FIG. 5 shows the first and second end-effectors 250a and
250b in a workpiece transport position. In this configuration, the
first spacer 254a spaces the first end-effector 250a apart from the
arm 234 by the first distance D.sub.1 and the second spacer 254b
spaces the second end-effector 250b apart from the arm 234 by the
second distance D.sub.2. When the first and second end-effectors
250a-b are over the arm 234, the first workpiece 101a can be
superimposed under the second workpiece 101b for transportation
along the track 132 as explained above with reference to FIG. 3B.
It will be appreciated that the first and second end-effectors 250a
and 250b can be spaced apart from the arm 234 by different
distances and using different techniques. The particular embodiment
shown in FIG. 5 uses fixed spacers 254a and 254b to provide a fixed
differential in the elevation between the first and second
end-effectors 250a and 250b that mitigates the need for complex
collision avoidance algorithms because the first and second
workpieces 101a-b are inherently held at elevations in which they
cannot collide with one another or other components of the robot
unit 134.
[0062] FIG. 6 illustrates the connection between the second
end-effector 250b and the second extension 236b of the arm 234 in
greater detail. In this embodiment, the pulley 445b is fixedly
attached to the spacer 254b, and a proximal end of the end-effector
250b is fixedly attached to the spacer 254b. The belt 446b
accordingly rotates the pulley 445b about the second rotation axis
A.sub.2-A.sub.2. The pulley 445b is mounted to a rotary fluid pass
through 500 by a bearing 502. The fluid pass through 500 includes a
passageway 504 through which a vacuum can be drawn or a pressurized
fluid can be pumped. The passageway 504 is in fluid communication
with a passageway 506 in the spacer 254b and a passageway 508
through the end-effector 250b such that the fluid can flow through
the second end-effector 250b. In the case of a vacuum end-effector,
a vacuum can be drawn through the passageways 504, 506 and 508 to
produce a suction at the workpiece holder 252 (FIG. 2A). A seal 510
between the fluid pass through 500 and the spacer 254b prevents
leaks between these two components. It will be appreciated that
alternate embodiments of applying a vacuum or driving a pressurized
fluid through an end-effector can be accomplished using other
structures. Additionally, the end-effectors can be vacuum
end-effectors as shown or they can be edge grip end-effectors that
use pressurized fluid to drive a linear plunger to hold the edge of
the workpiece against protruding tabs (See, e.g., U.S. patent
application Ser. Nos. 09/386,566; 09/386,590; and 09/386,568, all
of which have been incorporated by reference above).
[0063] Several embodiments of the transfer device 130 are also
expected to have a high degree of reliability. The transfer device
130 reduces the number of components and the complexity of the
operating software compared to transfer devices that have a
plurality of independent robot units in a single area. In general,
devices that reduce the complexity of a system are more reliable
and are easier to maintain because they have fewer components.
Therefore, several embodiments of the transfer device 130 are
expected to have low maintenance requirements and low down-time
caused by component failures.
[0064] From the foregoing, it will be appreciated that specific
embodiments of the invention have been described herein for
purposes of illustration, but that various modifications may be
made without deviating from the spirit and scope of the invention.
Accordingly, the invention is not limited except as by the appended
claims.
* * * * *