U.S. patent application number 15/333026 was filed with the patent office on 2017-02-09 for design of disk/pad clean with wafer and wafer edge/bevel clean module for chemical mechanical polishing.
The applicant listed for this patent is Applied Materials, Inc.. Invention is credited to Hui CHEN, Sen-Hou KO.
Application Number | 20170040160 15/333026 |
Document ID | / |
Family ID | 51521848 |
Filed Date | 2017-02-09 |
United States Patent
Application |
20170040160 |
Kind Code |
A1 |
CHEN; Hui ; et al. |
February 9, 2017 |
DESIGN OF DISK/PAD CLEAN WITH WAFER AND WAFER EDGE/BEVEL CLEAN
MODULE FOR CHEMICAL MECHANICAL POLISHING
Abstract
A method and apparatus for cleaning a substrate after chemical
mechanical planarizing (CMP) is provided. The apparatus comprises a
housing, a substrate holder rotatable on a first axis and
configured to retain a substrate in a substantially vertical
orientation, a first pad holder having a pad retaining surface
facing the substrate holder in a parallel and space apart relation,
the first pad holder rotatable on a second axis rotatable parallel
to the first axis, a first actuator operable to move the pad holder
relative to the substrate holder to change a distance defined
between the first axis and the second axis, and a second pad holder
disposed in the housing, the second pad holder having a pad
retaining surface facing the substrate holder in a parallel and
spaced apart relation, wherein the second pad holder is couple with
a rotary arm.
Inventors: |
CHEN; Hui; (Burlingame,
CA) ; KO; Sen-Hou; (Sunnyvale, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Applied Materials, Inc. |
Santa Clara |
CA |
US |
|
|
Family ID: |
51521848 |
Appl. No.: |
15/333026 |
Filed: |
October 24, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14198150 |
Mar 5, 2014 |
9508575 |
|
|
15333026 |
|
|
|
|
61794875 |
Mar 15, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/31053 20130101;
H01L 21/67219 20130101; H01L 21/67051 20130101; H01L 21/02065
20130101; B08B 3/10 20130101; H01L 21/02041 20130101; B08B 1/002
20130101; H01L 21/67046 20130101; H01L 21/02087 20130101; H01L
21/67178 20130101; B08B 1/006 20130101; B08B 1/04 20130101; H01L
21/68764 20130101 |
International
Class: |
H01L 21/02 20060101
H01L021/02; H01L 21/3105 20060101 H01L021/3105; B08B 1/00 20060101
B08B001/00; B08B 3/10 20060101 B08B003/10; H01L 21/67 20060101
H01L021/67; H01L 21/687 20060101 H01L021/687 |
Claims
1. A method for cleaning a substrate, comprising: spinning a
substrate disposed in a substantially vertical orientation;
providing a cleaning fluid to a surface of the spinning substrate;
pressing a first pad against the surface of the spinning substrate;
moving the first pad across the surface of the substrate along a
curved path; providing a polishing fluid to an exclusion region,
edge portion, or both the exclusion region and edge portion of the
spinning substrate; pressing a second pad against the exclusion
region, edge portion, or both the exclusion region and the edge
portion of the spinning substrate; and moving the second pad
laterally across the exclusion region, edge portion, or both the
exclusion region and edge portion of the substrate.
2. The method of claim 1, wherein pressing the first pad against
the surface of the spinning substrate further comprises spinning
the first pad.
3. The method of claim 2, wherein pressing the second pad against
the spinning substrate further comprises spinning the second
pad.
4. The method of claim 3, further comprising: placing the substrate
in a megasonic cleaning module prior to moving the first pad across
the surface of the substrate along the curved path; placing the
substrate in one or more brush modules after moving the second pad
laterally across the exclusion region, edge portion, or both the
exclusion region and edge portion of the substrate; and placing the
substrate in dryer after placing the substrate in the one or more
brush modules.
5. The method of claim 4, further comprising: planarizing the
surface of the substrate prior to placing the substrate in the
megasonic cleaning module.
6. The method of claim 4, further comprising: providing the
cleaning fluid to the substrate after moving the first pad across
the surface of the substrate along the curved path and prior to
placing the substrate in the one or more brush modules.
7. The method of claim 1, wherein the first pad has a diameter less
than half the diameter of the substrate.
8. The method of claim 7, wherein the second pad has a diameter
less than half the diameter of the substrate.
9. The method of claim 1, wherein the cleaning fluid is deionized
water.
10. A method for cleaning a substrate, comprising: rotating a
substrate disposed in a vertical orientation on a first axis;
providing a cleaning fluid to a surface of the rotating substrate;
pressing a cleaning pad against the rotating substrate; rotating
the cleaning pad on a second axis, wherein the first axis is
parallel to the second axis; moving the cleaning pad across the
substrate along a curved path; providing a polishing fluid to an
exclusion region, an edge portion, or both the exclusion region and
the edge portion of the rotating substrate; pressing a polishing
pad against the rotating substrate; rotating the polishing pad on a
third axis parallel the first axis and the second axis; and moving
the polishing pad laterally across the exclusion region, the edge
portion, or both the exclusion region and the edge portion of the
rotating substrate.
11. The method of claim 10, wherein the cleaning pad is coupled
with a rotary arm assembly comprising a rotary arm for moving the
cleaning pad across the substrate along the curved path.
12. The method of claim 11, wherein the rotary arm assembly further
comprises a lateral actuator mechanism for moving the cleaning pad
toward the substrate.
13. The method of claim 10, further comprising: contacting the
polishing pad with a conditioning disk; and rotating the
conditioning disk on a fourth axis parallel to the first axis and
the second axis to condition the polishing pad.
14. The method of claim 10, further comprising: placing the
substrate in a megasonic cleaning module prior to moving the
cleaning pad across the substrate along the curved path; placing
the substrate in one or more brush modules after moving the
polishing pad laterally across the exclusion region, the edge
portion, or both the exclusion region and the edge portion of the
rotating substrate; and placing the substrate in dryer after
placing the substrate in the one or more brush modules.
15. The method of claim 14, further comprising: planarizing a
surface of the substrate prior to placing the substrate in the
megasonic cleaning module.
16. The method of claim 14, further comprising: providing the
cleaning fluid to the substrate after moving the cleaning pad
laterally across the surface of the substrate and prior to placing
the substrate in the one or more brush modules.
17. The method of claim 10, wherein the cleaning pad has a diameter
less than half the diameter of the substrate.
18. The method of claim 10, wherein the polishing pad has a
diameter less than half the diameter of the substrate.
19. The method of claim 10, wherein the cleaning fluid is deionized
water.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 14/198,150, filed Mar. 5, 2014, which claims benefit of
U.S. Provisional Patent Application Ser. No. 61/794,875, filed Mar.
15, 2013, both of which are herein incorporated by reference in
their entirety.
BACKGROUND
[0002] Field
[0003] Implementations of the present invention relate to a method
and apparatus for cleaning a substrate after chemical mechanical
planarization (CMP).
[0004] Description of the Related Art
[0005] In the process of fabricating modern semiconductor
integrated circuits (ICs), planarizing surfaces prior to depositing
subsequent layers is often necessary to ensure accurate formation
of photoresist masks and to maintain stack tolerances. One method
for planarizing a layer during IC fabrication is chemical
mechanical planarizing (CMP). In general, CMP involves the relative
movement of the substrate held in a polishing head against a
polishing material to remove surface irregularities from the
substrate. In a CMP process, the polishing material is wetted with
a polishing fluid that may contain at least one of an abrasive or
chemical polishing composition. This process may be electrically
assisted to electrochemically planarize conductive material on the
substrate.
[0006] Planarizing hard materials such as oxides typically requires
that the polishing fluid or the polishing material itself include
abrasives. As the abrasives often cling or become partially
embedded in the layer of material being polished, the substrate is
processed on a buffing module to remove the abrasives from the
polished layer. The buffing module removes the abrasives and
polishing fluid used during the CMP process by moving the
substrate, which is still retained in the polishing head against a
buffing material in the presence of deionized water or chemical
solutions. The buffing module is substantially identical to the CMP
module except for the polishing fluids utilized and the material on
which the substrate is processed.
[0007] Once buffed, the substrate is transferred to a series of
cleaning modules that further remove any remaining abrasive
particles and/or other contaminants that cling to the substrate
after the planarizing and buffing process before they can harden on
the substrate and create defects. The cleaning modules may include,
for example, a megasonic cleaner, a scrubber or scrubbers, and a
dryer. The cleaning modules that support the substrates in a
vertical orientation are especially advantageous, as they also
utilize gravity to enhance removal of particles during the cleaning
process, and are also typically more compact.
[0008] Although present CMP processes have been shown to be robust
and reliable systems, the configuration of the system equipment
requires the buffing module to utilize critical space, which could
alternatively be utilized for additional CMP modules. However,
certain polishing fluids, for example those using cerium oxide, are
particularly difficult to remove and conventionally require
processing the substrate in buffing module before transferring the
substrate to the cleaning module as conventional cleaning modules
have not demonstrated the ability to satisfactorily remove abrasive
particles from oxide surfaces that have not been buffed prior to
cleaning.
[0009] Therefore, there is a need in the art for an improved CMP
process and cleaning module.
SUMMARY
[0010] Implementations of the present invention relate to a method
and apparatus for cleaning a substrate after chemical mechanical
planarizing (CMP). In one implementation, a particle cleaning
module is provided. The particle cleaning module comprises a
housing, a substrate holder disposed in the housing, the substrate
holder configured to retain a substrate in a substantially vertical
orientation, the substrate holder rotatable on a first axis, a
first pad holder disposed in the housing, the first pad holder
having a pad retaining surface facing the substrate holder in a
parallel and space apart relation, the first pad holder rotatable
on a second axis rotatable parallel to the first axis, a first
actuator operable to move the first pad holder relative to the
substrate holder to change a distance defined between the first
axis and the second axis, and a second pad holder disposed in the
housing, the second pad holder having a pad retaining surface
facing the substrate holder in a parallel and spaced apart
relation, the second pad holder rotatable on a third axis parallel
to the first axis and the second axis.
[0011] In one implementation, a particle cleaning module is
provided. The particle cleaning module comprises a housing, a
substrate holder disposed in the housing, a first pad holder
disposed in the housing, a second pad holder disposed in the
housing, and a rotary arm assembly. The substrate holder is
configured to retain a substrate in a substantially vertical
orientation with the substrate holder rotatable on a first axis.
The first pad holder has a pad retaining surface facing the
substrate holder in a parallel and spaced apart relation, the first
pad holder rotatable on a second axis rotatable parallel to the
first axis. A first actuator is operable to move the first pad
holder relative to the substrate holder to change a distance
defined between the first axis and the second axis. The second pad
holder has a pad retaining surface facing the substrate holder in a
parallel and spaced apart relation, the second pad holder rotatable
on a third axis parallel to the first axis and the second axis. The
rotary arm assembly comprises a rotary arm coupled with the second
pad holder and operable for sweeping the second pad holder across
the surface of the substrate and a lateral actuator mechanism form
moving the rotary arm toward the substrate.
[0012] In another implementation, a method for cleaning a substrate
is provided. The method comprises spinning a substrate disposed in
a vertical orientation, providing a cleaning fluid to a surface of
the spinning substrate, pressing a first pad against the spinning
substrate, moving the first pad laterally across the substrate,
providing a polishing fluid to an edge portion of the spinning
substrate, pressing a second pad against the spinning substrate,
and moving the second pad laterally across the edge of the
substrate. Pressing the first pad against the spinning substrate
may further comprise spinning the first pad. Pressing the first pad
against the spinning substrate may further comprise spinning the
first pad. The method may further comprise placing the substrate in
a megasonic cleaning module prior to moving the first pad laterally
across the substrate, placing the substrate in one or more brush
modules after moving the second pad laterally across the edge of
the substrate and placing the substrate in dryer after placing the
substrate in the one or more brush modules. The method may further
comprise planarizing a surface of the substrate prior to placing
the substrate in the megasonic cleaning module. The method may
further comprise providing the cleaning fluid to the substrate
after moving the first pad laterally across the substrate and prior
to placing the substrate in the one or more brush modules.
[0013] In yet another implementation, a method for cleaning a
substrate is provided. The method comprises spinning a substrate
disposed in a vertical orientation, providing a cleaning fluid to a
surface of the spinning substrate, pressing a first pad against the
spinning substrate, moving the first pad across the substrate along
a curved path, providing a polishing fluid to an exclusion region
and/or edge portion of the spinning substrate, pressing a second
pad against the spinning substrate and moving the second pad
laterally across the edge of the substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] So that the manner in which the above recited features of
the present invention can be understood in detail, a more
particular description of the invention, briefly summarized above,
may be had by reference to implementations, some of which are
illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only typical implementations
of this invention and are therefore not to be considered limiting
of its scope, for the invention may admit to other equally
effective implementations.
[0015] FIG. 1 is a schematic illustration of a cross-section of a
portion of a substrate;
[0016] FIG. 2 illustrates a top view of a semiconductor substrate
chemical mechanical planarization system having a cleaning system
which includes one implementation of a particle cleaning module
according to implementations described herein;
[0017] FIG. 3 is a front view of cleaning system depicted in FIG. 2
according to implementations described herein;
[0018] FIG. 4 is a cross-sectional view of the particle cleaning
module depicted in FIG. 2 according to implementations described
herein;
[0019] FIG. 5 is a cross-sectional view of the particle cleaning
module taken along the section line 5-5 of FIG. 4 according to
implementations described herein;
[0020] FIG. 6 is a cross-sectional view of the particle cleaning
module taken along the section line 6-6 of FIG. 4 according to
implementations described herein;
[0021] FIG. 7 is a top view of a pad holder engaging a pad with a
substrate retained by the substrate holder within the particle
cleaning module of FIG. 2 according to implementations described
herein;
[0022] FIG. 8 is a top schematic view of the particle cleaning
module having a pad conditioning assembly disposed therein;
[0023] FIGS. 9A-9C are schematic views of the disk pad holder
according to implementations described herein;
[0024] FIGS. 10A-10D are schematic view of the disk pad holder
according to implementations described herein;
[0025] FIG. 11 is a schematic cross-sectional view of another
implementation of a particle cleaning module according to
implementations described herein;
[0026] FIG. 12 is a cross-sectional schematic view of another
implementation of a disk pad holder according to implementations
described herein;
[0027] FIG. 13 is another schematic view of the particle cleaning
module of FIG. 11 according to implementations described
herein;
[0028] FIG. 14 is another schematic view of the particle cleaning
module of FIG. 11 according to implementations described
herein;
[0029] FIG. 15 is a schematic view of a portion of a particle
cleaning module illustrating another implementation of a pad
conditioning assembly according to implementations described
herein; and
[0030] FIG. 16 is a schematic view of another implementation of an
edge pad polishing assembly according to implementations described
herein.
[0031] To facilitate understanding, identical reference numerals
have been used, wherever possible, to designate identical elements
that are common to the Figures. Additionally, elements of one
implementation may be advantageously adapted for utilization in
other implementations described herein.
DETAILED DESCRIPTION
[0032] Implementations of the present invention relate to a method
and apparatus for cleaning a substrate after chemical mechanical
planarizing (CMP). More specifically implementations of the present
invention provide improved methods and apparatus for cleaning
and/or polishing the exclusion region and/or edge of a substrate.
Abrasive particles (e.g., cerium oxide (CeO)) used in oxide CMP are
difficult to remove using traditional PVA brush scrubbing and often
require performance of a buffing process on an additional platen on
the polishing tool. However even with buffing on the polishing
platen particles at the wafer edge (e.g. 2 mm) are very difficult
to remove.
[0033] Certain implementations described herein provide a clean
process where slurry polishing is performed at the exclusion region
and/or edge of a wafer after particle cleaning. Certain
implementations of the current invention provide an apparatus where
a slurry polishing process at the exclusion region and/or edge of a
wafer is implemented without affecting the polishing performance in
the device area. The apparatus, described below as a particle
cleaning module, advantageously allows for increased utilization
and throughput of the CMP system, while reducing the amount and
cost of consumables needed to effectively clean a substrate as
further described below.
[0034] The particle cleaning module has a wafer chuck, which may
support a full wafer size and a disk brush holder with a diameter
of less than 50 mm. The wafer chuck speed may be more than 500 rpm
and the disk brush holder speed may be more than 1000 rpm. A soft
pad, such as politex type material, may be used as a cleaning pad.
The cleaning pad may be adhered on top of the disk brush holder
with a pressure sensitive adhesive. During the cleaning process,
the wafer is rotated by the wafer chuck and the disk brush with the
soft pad rotates and sweeps from the center of the wafer to the
edge of the wafer or vice versa. The contact pressure and/or gap
between the soft pad and the wafer may be controlled by a linear
motor. This motion may be repeated several times until the abrasive
particles are removed from most of the wafer surface, except the
wafer edge at .ltoreq.2 mm edge exclusion. Afterward, a polishing
step is performed where a polishing pad is moved to the edge of the
wafer and the slurry is delivered next to the polishing pad where
the wafer and the pad are rotated and contacted during the
polishing. It is desirable to have the polishing pad only polish
the exclusion region and/or edge region without touching the device
region. The polishing pad may rotate at high speed as well as sweep
back and forth at the edge of the wafer. In certain implementations
it desirable to have separate pads, a first pad for removing
particles from the surface of the wafer and a second pad for
polishing at the wafer edge where a local slurry is delivered.
[0035] In certain implementations, the particle cleaning module
uses a rotary arm in place of the lateral linear motion design. The
Disk/Pad/Fluid Jet module design uses the rotary arm motion concept
to control the Disk/Pad/Fluid Jet to scan on the wafer surface. By
using the rotary arm motion design, the processing tank sealing and
servicing is easier and production costs are cheaper than the
current lateral linear motion Disk/Pad/Fluid Jet design.
[0036] In certain implementations, the particle cleaning module
design provides a common design layout for multi-wafer processing.
For example, by replacing the Disk, Pad or Fluid Jet, it can
perform many kinds of wafer cleaning processes in this common
module. The particle cleaning module also provides a flexible edge
clean disk/pad for wafer edge cleaning and wafer bevel cleaning.
The Disk/Pad/Fluid Jet may be moved in and out to control the
processing force and distance to wafer surface. The Disk/Pad clean
pressure force on the wafer may be set from 0.about.5 Lb. Further,
the wafer vacuum chuck design provides full wafer support for
higher Disk/Pad processing force. The wafer gripper design provides
wafer edge-contact for both sides of the wafer (front and back)
during processing and rinsing.
[0037] Implementations described herein will be described below in
reference to a planarizing process and composition that can be
carried out using chemical mechanical polishing process equipment,
such as MIRRA.TM., MIRRA MESA.TM., REFLEXION.RTM., REFLEXION
LK.TM., and REFLEXION.RTM. GT.TM. chemical mechanical planarizing
systems, available from Applied Materials, Inc. of Santa Clara,
Calif. Other planarizing modules, including those that use
processing pads, planarizing webs, or a combination thereof, and
those that move a substrate relative to a planarizing surface in a
rotational, linear, or other planar motion may also be adapted to
benefit from the implementations described herein. In addition, any
system enabling chemical mechanical polishing using the methods or
compositions described herein can be used to advantage. The
following apparatus description is illustrative and should not be
construed or interpreted as limiting the scope of the
implementations described herein.
[0038] FIG. 1 is a schematic illustration of a cross-section of a
portion of a substrate 100. With reference to FIG. 1, a substrate
100 may include two major surfaces 102a, 102b and an edge 104. Each
major surface 102a, 102b of the substrate 100 may include a device
region 106a, 106b and an exclusion region 108a, 108b. (Typically
however, only one of the two major surfaces 102a, 102b will include
a device region and an exclusion region.) The exclusion regions
108a, 108b may serve as buffers between the device regions 106a,
106b and the edge 104. The edge 104 of a substrate 100 may include
an outer edge 110 and bevels 112, 114. The bevels 112, 114 may be
located between the outer edge 110 and the exclusion regions 108a,
108b of the two major surfaces 102a, 102b. The present invention is
adapted to clean and/or polish the outer edge 110 and at least one
bevel 112, 114 of a substrate 100 without affecting the device
regions 106a, 106b. In some implementations, all or part of the
exclusion regions 108a, 108b may be cleaned or polished as
well.
[0039] FIG. 2 illustrates a top view of a semiconductor substrate
chemical mechanical planarization (CMP) system 200 having a
cleaning system 216 that includes one implementation of a particle
cleaning module 282 of the present invention. Although the
exemplary configurations are provided for the CMP system 200 and
cleaning system 216 in FIG. 2, it is contemplated that
implementations of the particle cleaning module 282 of the present
invention may be utilized alone, or with cleaning systems having
alternative configurations and/or CMP systems having alternative
configurations.
[0040] In addition to the cleaning system 216, the exemplary CMP
system 200 generally includes a factory interface 202, a loading
robot 204, and a planarizing module 206. The loading robot 204 is
disposed proximate the factory interface 202 and the planarizing
module 206 to facilitate the transfer of substrates 100
therebetween.
[0041] A controller 208 is provided to facilitate control and
integration of the modules of the CMP system 200. The controller
208 comprises a central processing unit (CPU) 210, a memory 212 and
support circuits 214. The controller 208 is coupled to the various
components of the CMP system 200 to facilitate control of, for
example, the planarizing cleaning and transfer processes.
[0042] The factory interface 202 generally includes an interface
robot 220 and one or more substrate cassettes 218. The interface
robot 220 is employed to transfer substrates 100 between the
substrate cassettes 218, the cleaning system 216 and an input
module 224. The input module 224 is positioned to facilitate
transfer of substrates 100 between the planarizing module 206 and
the factory interface 202 as will be further described below.
[0043] Optionally, polished substrates exiting the cleaning system
216 may be tested in a metrology system 280 disposed in the factory
interface 202. The metrology system 280 may include an optical
measuring device, such as the NovaScan 420, available from Nova
Measuring Instruments, Inc. located in Sunnyvale, Calif. The
metrology system 280 may include a buffer station (not shown) for
facilitating entry and egress of substrates from the optical
measuring device or other metrology device. One such suitable
buffer is described in U.S. Pat. No. 6,244,931, issued Jun. 12,
2001 to Pinson, et al.
[0044] The planarizing module 206 includes at least one CMP
station. It is contemplated that the CMP station maybe configured
as an electrochemical mechanical planarizing station. In the
implementation depicted in FIG. 2, the planarizing module 206
includes a plurality of CMP stations, illustrated as a first
station 228, a second station 230 and a third station 232 disposed
in an environmentally controlled enclosure 288. The first station
228 includes a conventional CMP station configured to perform an
oxide planarization process utilizing an abrasive containing
polishing fluid. It is contemplated that CMP processes to
planarized other materials may be alternatively performed,
including the use of other types of polishing fluids. As the CMP
process is conventional in nature, further description thereof has
been omitted for the sake of brevity. The second station 230 and
the third station 232 will be discussed in detail further
below.
[0045] The exemplary planarizing module 206 also includes a
transfer station 236 and a carousel 234 that are disposed on an
upper or first side 238 of a machine base 240. In one
implementation, the transfer station 236 includes an input buffer
station 242, an output buffer station 244, a transfer robot 246 and
a load cup assembly 248. The loading robot 204 is configured to
retrieve substrates from the input module 224 and transfer the
substrates to the input buffer station 242. The loading robot 204
is also utilized to return polished substrates from the output
buffer station 244 to the input module 224, from where the polished
substrates are then advanced through the cleaning system 216 prior
to being returned to the substrate cassettes 218 coupled to the
factory interface 202 by the interface robot 220. The transfer
robot 246 is utilized to move substrates between the buffer
stations 242, 244 and the load cup assembly 248.
[0046] In one implementation, the transfer robot 246 includes two
gripper assemblies, each having pneumatic gripper fingers that hold
the substrate by the substrate's edge. The transfer robot 246 may
simultaneously transfer a substrate to be processed from the input
buffer station 242 to the load cup assembly 248 while transferring
a processed substrate from the load cup assembly 248 to the output
buffer station 244. An example of a transfer station that may be
used to advantage is described in U.S. Pat. No. 6,156,124, issued
Dec. 5, 2000 to Tobin.
[0047] The carousel 234 is centrally disposed on the machine base
240. The carousel 234 typically includes a plurality of arms 250,
each supporting a polishing head assembly 252. Two of the arms 250
depicted in FIG. 2 are shown in phantom such that a planarizing
surface of a polishing pad 226 of the first station 228 and the
transfer station 236 may be seen. The carousel 234 is indexable
such that the polishing head assemblies 252 may be moved between
the planarizing stations 228, 230, 232 and the transfer station
236. One carousel that may be utilized to advantage is described in
U.S. Pat. No. 5,804,507, issued Sep. 8, 1998 to Perlov, et al.
[0048] The cleaning system 216 removes polishing debris, abrasives,
polishing fluid, and/or excess deposited material from the polished
substrates that remains after polishing. The cleaning system 216
includes a plurality of cleaning modules 260, a substrate handler
266, a dryer 262 and an output module 256. The substrate handler
266 retrieves a processed substrate 100 returning from the
planarizing module 206 from the input module 224 and transfers the
substrate 100 through the plurality of cleaning modules 260 and
dryer 262. The dryer 262 dries substrates exiting the cleaning
system 216 and facilitates substrate transfer between the cleaning
system 216 and the factory interface 202 by the interface robot
220. The dryer 262 may be a spin-rinse-dryer or other suitable
dryer. One example of a suitable dryer 262 may be found as part of
the MESA.TM. or Desica.RTM. Substrate Cleaners, both available from
Applied Materials, Inc., of Santa Clara, Calif.
[0049] In the implementation depicted in FIG. 2, the cleaning
modules 260 utilized in the cleaning system 216 include a megasonic
clearing module 264A, the particle cleaning module 282, a first
brush module 264B and a second brush module 264C. However, it is to
be appreciated that the particle cleaning module 282 of the present
invention may be used with cleaning systems incorporating one or
more modules having one or more types of modules. Each of the
cleaning modules 260 is configured to process a vertically oriented
substrate, i.e., one in which the polished surface is in a
substantially vertical plane. The vertical plane is represented by
the Y-axis, which is perpendicular to the X-axis and Z-axis shown
in FIG. 2. The particle cleaning module 282 is discussed in detail
further below with reference to FIG. 4.
[0050] In operation, the CMP system 200 is initiated with the
substrate 100 being transferred from one of the substrate cassettes
218 to the input module 224 by the interface robot 220. The loading
robot 204 then moves the substrate from the input module 224 to the
transfer station 236 of the planarizing module 206. The substrate
100 is loaded into the polishing head assembly 252 moved over and
polished against the polishing pad 226 while in a horizontal
orientation. Once the substrate is polished, polished substrates
100 are returned to the transfer station 236 from where the loading
robot 204 may transfer the substrate 100 from the planarizing
module 206 to the input module 224 while rotating the substrate to
a vertical orientation. The substrate handler 266 then retrieves
the substrate from the input module 224 transfers the substrate
through the cleaning modules 260 of the cleaning system 216. Each
of the cleaning modules 260 is adapted to support a substrate in a
vertical orientation throughout the cleaning process. Once cleaned,
the cleaned substrate 100 is to the output module 256. The cleaned
substrate 100 is returned to one of the substrate cassettes 218 by
the interface robot 220 while returning the cleaned substrate 100
to a horizontal orientation. Optionally, the interface robot 220
may transfer the cleaned substrate to the metrology system 280
prior to the substrate's return to one of the substrate cassettes
218.
[0051] Although any suitable substrate handler may be utilized, the
substrate handler 266 depicted in FIG. 2 includes a robot 268
having at least one substrate gripper (two substrate grippers 274,
276 are shown) that is configured to transfer substrates between
the input module 224, the cleaning modules 260 and the dryer 262.
Optionally, the substrate handler 266 may include a second robot
(not shown) configured to transfer the substrate between the last
cleaning module 260 and the dryer 262 to reduce cross
contamination.
[0052] In the implementation depicted in FIG. 2, the substrate
handler 266 includes a rail 272 coupled to a partition 258
separating the substrate cassettes 218 and interface robot 220 from
the cleaning system 216. The robot 268 is configured to move
laterally along the rail 272 to facilitate access to the cleaning
modules 260, dryer 262 and the input and output modules 224,
256.
[0053] FIG. 3 depicts a front view of the substrate handler 266
according to one implementation of the invention. The robot 268 of
the substrate handler 266 includes a carriage 302, a mounting plate
304 and the substrate grippers 274, 276. The carriage 302 is
slidably mounted on the rail 272 and is driven horizontally by an
actuator 306 along a first axis of motion A.sub.1 defined by the
rail 272 which is parallel to the Z-axis. The actuator 306 includes
a motor 308 coupled to a belt 310. The carriage 302 is attached to
the belt 310. As the motor 308 advances the belt 310 around the
sheave 312 positioned at one end of the cleaning system 216, the
carriage 302 moves along the rail 272 to selectively position the
robot 268. The motor 308 may include an encoder (not shown) to
assist in accurately positioning the robot 268 over the input and
output modules 224, 256 and the various cleaning modules 260.
Alternatively, the actuator 306 may be any form of a rotary or
linear actuator capable of controlling the position of the carriage
302 along the rail 272. In one implementation, the carriage 302 is
driven by a linear actuator having a belt drive, such as the GL15B
linear actuator commercially available from THK Co., Ltd. located
in Tokyo, Japan.
[0054] The mounting plate 304 is coupled to the carriage first 302.
The mounting plate 304 includes at least two parallel tracks 316A-B
along which the positions of the substrate grippers 274, 276 are
independently actuated along a second and third axes of motion
A.sub.2, A.sub.3. The second and third axes of motion A.sub.2,
A.sub.3 are oriented perpendicular to the first axis A.sub.1 and
are parallel to the Y-axis.
[0055] FIG. 4 depicts a cross-sectional view of the particle
cleaning module 282 of FIG. 2. The particle cleaning module 282
includes a housing 402, a substrate rotation assembly 404, a first
pad actuation assembly 406 and a second pad actuation assembly 470.
Although a first pad actuation assembly 406 and a second pad
actuation assembly 470 are shown, it should be understood that the
implementations described herein may be performed with a single pad
actuation assembly. For example, the first pad actuation assembly
406 and the second pad actuation assembly 470 may be positioned in
separate housings. The housing 402 includes an opening 408 at a top
of the housing and a substrate receiver 410 at a bottom 418 of the
housing. A drain 468 is formed through the bottom 418 of the
housing 402 to allow fluids to be removed from the housing 402. The
opening 408 allows the robot 268 (not shown in FIG. 4) to
vertically transfer the substrate to an internal volume 412 defined
within the housing 402. The housing 402 may optionally include a
lid 430 that can open and close to allow the robot 268 in and out
of the housing 402.
[0056] The substrate receiver 410 has a substrate receiving slot
432 facing upwards parallel to the Y-axis. The substrate receiving
slot 432 is sized to accept the perimeter of the substrate 100,
thereby allowing the one of the substrate grippers 274, 276 of the
substrate handler 266 to place the substrate 100 in the substrate
receiving slot 432 in a substantially vertical orientation. The
substrate receiver 410 is coupled to a Z-Y actuator 411. The Z-Y
actuator 411 may be actuated to move the substrate receiver 410
upwards in the Y-axis to align a centerline of the substrate 100
disposed in the substrate receiver 410 with a centerline of the
substrate rotation assembly 404. Once the centerline of the
substrate 100 is aligned with the centerline of the substrate
rotation assembly 404, the Z-Y actuator 411 may be actuated to move
the substrate receiver 410 in the Z-axis to contact the substrate
100 against the substrate rotation assembly 404, which then
actuates to chuck the substrate 100 to the substrate rotation
assembly 404. After the substrate 100 has been chucked to the
substrate rotation assembly 404, the Z-Y actuator 411 may be
actuated to move the substrate receiver 410 in the Y-axis clear of
the substrate 100 and the substrate rotation assembly 404 so that
the substrate 100 held by the substrate rotation assembly 404 may
be rotated without contacting the substrate receiver 410.
[0057] The substrate rotation assembly 404 is disposed in the
housing 402 and includes a substrate holder 414 coupled to a
substrate rotation mechanism 416. The substrate holder 414 may be
an electrostatic chuck, a vacuum chuck, a mechanical gripper or any
other suitable mechanism for securely holding the substrate 100
while the substrate is rotated during processing within the
particle cleaning module 282. Preferably, the substrate holder 414
is either an electrostatic chuck or a vacuum chuck.
[0058] FIG. 5 is a cross-sectional view of the particle cleaning
module 282 taken along the section line 5-5 of FIG. 4 thus
illustrating a face 504 of the substrate holder 414. Referring to
both FIG. 4 and FIG. 5, the face 504 of the substrate holder 414
includes one or more apertures 502 fluidly coupled to a vacuum
source 497. The vacuum source 497 is operable to apply a vacuum
between the substrate 100 and the substrate holder 414, thereby
securing the substrate 100 and the substrate holder 414. Once the
substrate 100 is held by the substrate holder 414, the substrate
receiver 410 moves downward in a vertical direction parallel to the
Y-axis towards the bottom 418 of the housing 402 to be clear of the
substrate, as seen in FIG. 5. The substrate receiver 410 may move
in a horizontal direction towards an edge 420 of the housing 402 to
be further clear of the substrate.
[0059] The substrate holder 414 is coupled to the substrate
rotation mechanism 416 by a first shaft 423 that extends through a
hole 424 formed through the housing 402. The hole 424 may
optionally include sealing members 426 to provide a seal between
the first shaft 423 and the housing 402. The substrate holder 414
is controllably rotated by the substrate rotation mechanism 416.
The substrate rotation mechanism 416 may be an electrical motor, an
air motor, or any other motor suitable for rotating the substrate
holder 414 and substrate 100 chucked thereto. The substrate
rotation mechanism 416 is coupled to the controller 208. In
operation, the substrate rotation mechanism 416 rotates the first
shaft 423, which rotates the substrate holder 414 and the substrate
100 secured thereto. In one implementation the substrate rotation
mechanism 416 rotates the substrate holder 414 (and substrate 100)
at a rate of at least 500 revolutions per minute (rpm).
[0060] The first pad actuation assembly 406 includes a pad rotation
mechanism 436, a pad cleaning head 438, and a lateral actuator
mechanism 442. The pad cleaning head 438 is located in the internal
volume 412 of the housing 402 and includes a first pad holder 434
that holds a pad 444 and a fluid delivery nozzle 450. The fluid
delivery nozzle 450 is coupled to a fluid delivery source 498 that
provides deionized water, a chemical solution or any other suitable
fluid to the pad 444 during cleaning the substrate 100. The lid 430
may be moved to a position that closes the opening 408 of the
housing 402 above the fluid delivery nozzle 450 to prevent fluids
from being spun out of the housing 402 during processing.
[0061] A centerline of the first pad holder 434 may be aligned with
the centerline of the substrate holder 414. The first pad holder
434 (and pad 444) has a diameter much less than that of the
substrate 100, for example at least less than half the diameter of
the substrate or even as much as less than about one eighth the
diameter of the substrate. In one implementation, the first pad
holder 434 (and pad 444) may have a diameter of less than about 25
mm. The first pad holder 434 may holds the pad 444 utilizing
clamps, vacuum, adhesive or other suitable technique that allows
for the pad 444 to periodically be replaced as the pad 444 becomes
worn after cleaning a number of substrates 100.
[0062] The pad 444 may be fabricated from a polymer material, such
as porous rubber, polyurethane and the like, for example, a
POLYTEX.TM. pad available from Rodel, Inc. of Newark, Del. In one
implementation, the pad holder 434 may be used to a hold a brush or
any other suitable cleaning device. The first pad holder 434 is
coupled to the pad rotation mechanism 436 by a second shaft 446.
The second shaft 446 is oriented parallel to the Z-axis and extends
from the internal volume 412 through an elongated slit formed
through the housing 402 to the pad rotation mechanism 436. The pad
rotation mechanism 436 may be an electrical motor, an air motor, or
any other suitable motor for rotating the first pad holder 434 and
pad 444 against the substrate. The pad rotation mechanism 436 is
coupled to the controller 208. In one implementation, the pad
rotation mechanism 436 rotates the first pad holder 434 (and pad
444) at a rate of at least about 1000 rpm.
[0063] The pad rotation mechanism 436 is coupled to bracket 454 by
an axial actuator 440. The axial actuator 440 is coupled to the
controller 208 or other suitable controller and is operable to move
the first pad holder 434 along the Z-axis to move the pad 444
against and clear of the substrate 100 held by the substrate holder
414. The axial actuator 440 may be a pancake cylinder, linear
actuator or any other suitable mechanism for moving the first pad
holder 434 in a direction parallel to the Z-axis. In operation,
after the substrate holder 414 is in contact with and holding the
substrate, the axial actuator 440 drives the first pad holder 434
in a z-direction to make contact with the substrate 100.
[0064] The bracket 454 is coupled to a base 462 by the lateral
actuator mechanism 442 by a carriage 456 and rail 458 that allows
the pad cleaning head 438 to move laterally in a direction parallel
to the X-axis, as depicted in FIG. 6. The carriage 456 is slidably
mounted on the rail 458 and is driven horizontally by the lateral
actuator mechanism 442 to scan the pad 444 across the substrate
100. The lateral actuator mechanism 442 may be a lead screw, a
linear actuator or any other suitable mechanism for moving the pad
cleaning head 438 horizontally. The lateral actuator mechanism 442
is coupled to controller 208 or other suitable controller.
[0065] The second pad actuation assembly 470 includes a pad
rotation mechanism 472, a pad polishing head 474, and a lateral
actuator mechanism 476. The pad polishing head 474 is located in
the internal volume 412 of the housing 402 and includes a second
pad holder 478 that holds a polishing pad 480 and a fluid delivery
nozzle 482. The fluid delivery nozzle 450 is coupled to a fluid
delivery source 484 that provides polishing slurry, deionized
water, a chemical solution or any other suitable fluid to the
polishing pad 480 during polishing of the exclusion region and/or
edge region of the substrate 100. The lid 430 may be moved to a
position that closes the opening 408 of the housing 402 above the
fluid delivery nozzle 482 to prevent fluids from being spun out of
the housing 402 during processing.
[0066] A centerline of the second pad holder 478 may be aligned
with the edge of the substrate 100. The second pad holder 478 (and
polishing pad 480) has a diameter much less than that of the
substrate 100, for example at least less than half the diameter of
the substrate or even as much as less than about one eighth the
diameter of the substrate. In one implementation, the second pad
holder 478 (and polishing pad 480) may have a diameter of less than
about 50 mm. The second pad holder 478 may hold the polishing pad
480 utilizing clamps, vacuum, adhesive or other suitable techniques
that allow for the polishing pad 480 to periodically be replaced as
the polishing pad 480 becomes worn after polishing the edge of a
number of substrates 100.
[0067] The polishing pad 480 may be fabricated from a polymer
material, such as porous rubber, polyurethane and the like, for
example, a POLYTEX.TM. pad available from Rodel, Inc. of Newark,
Del. The polishing pad 480 may be a fixed abrasive pad. The second
pad holder 478 is coupled to the pad rotation mechanism 472 by a
third shaft 486. The third shaft 486 is oriented parallel to the
Z-axis and extends from the internal volume 412 through an
elongated slit formed through the housing 402 to the pad rotation
mechanism 472. The pad rotation mechanism 472 may be an electrical
motor, an air motor, or any other suitable motor for rotating the
second pad holder 478 and polishing pad 480 against the substrate
100. The pad rotation mechanism 472 is coupled to the controller
208. In one implementation, the pad rotation mechanism 472 rotates
the second pad holder 478 (and polishing pad 480) at a rate of at
least about 1000 rpm.
[0068] The pad rotation mechanism 472 is coupled to bracket 488 by
an axial actuator 490. The axial actuator 490 is coupled to the
controller 208 or other suitable controller and is operable to move
the second pad holder 478 along the Z-axis to move the polishing
pad 480 against and clear of the substrate 100 held by the
substrate holder 414. The axial actuator 490 may be a pancake
cylinder, linear actuator or any other suitable mechanism for
moving the second pad holder 478 in a direction parallel to the
Z-axis. In operation, after the substrate holder 414 is in contact
with and holding the substrate, the axial actuator 490 drives the
second pad holder 478 in a z-direction to make contact with the
substrate 100.
[0069] The bracket 488 is coupled to a base 492 by the lateral
actuator mechanism 476 by a carriage 494 and rail 496 that allows
the pad polishing head 474 to move laterally in a direction
parallel to the X-axis, as depicted in FIG. 6. The carriage 494 is
slidably mounted on the rail 496 and is driven horizontally by the
lateral actuator mechanism 476 to scan the polishing pad 480 across
the substrate 100. The lateral actuator mechanism 476 may be a lead
screw, a linear actuator or any other suitable mechanism for moving
the pad polishing head 474 horizontally. The lateral actuator
mechanism 476 is coupled to controller 208 or other suitable
controller.
[0070] Scanning the pad 444 across the substrate 100 in the
particle cleaning module 282 has effectively demonstrated the
ability to effectively remove particles, such as abrasives from the
polishing fluid, from the surface of the substrate 100. Further,
scanning the polishing pad 480 across the exclusion region and/or
edge region has demonstrated the ability to effectively remove
particles, such as abrasives, excess deposited material, and/or
polishing slurry from the surface of the substrate 100, for
example, the exclusion region and/or edge region of the substrate.
Thus, the inclusion of a polishing step at the wafer edge in
addition to particle cleaning has effectively demonstrated edge
defect improvement. Accordingly, the need for a dedicated buffing
station on the polishing module is substantially eliminated.
[0071] FIG. 7 is a side view of the first pad holder 434 and the
second pad holder 478 engaging pad 444 and pad 480 respectively
with the substrate 100 retained by the substrate holder 414. In
operation, with respect to the first pad holder 434, the axial
actuator 440 urges the pad 444 against the substrate 100 rotated by
the substrate rotation mechanism 416 while the pad rotation
mechanism 436 spins the pad 444. The lateral actuator mechanism 442
moves the first pad holder 434 and pad 444 in a horizontal
direction across the surface of the substrate 100. While the pad
444 is in contact with the substrate 100, the fluid delivery nozzle
450 provides at least one of deionized water, a chemical solution
or any other suitable fluid to the surface of the substrate 100
being processed by the pad 444. Accordingly, the pad 444 cleans the
surface of the substrate with minimal movement.
[0072] In operation, with respect to the second pad holder 478, the
axial actuator 490 urges the polishing pad 480 against the
substrate 100 rotated by the substrate rotation mechanism 416 while
the pad rotation mechanism 472 spins the polishing pad 480. The
lateral actuator mechanism 476 moves the second pad holder 478 and
the polishing pad 480 in a horizontal direction across the surface
of the substrate 100. While the polishing pad 480 is in contact
with the exclusion region and/or edge region of the substrate 100,
the fluid delivery nozzle 482 provides at least one of polishing
slurry, deionized water, a chemical solution or any other suitable
fluid to the surface of the substrate 100 being processed by the
polishing pad 480. Accordingly, the pad 444 cleans the edge of the
substrate with minimal movement.
[0073] It should be understood that although FIG. 7 depicts pad 444
and polishing pad 480 simultaneously contacting the substrate 100,
the implementations described herein do not require simultaneous
contact of the substrate by the pad 444 and the polishing pad 480.
For example, the particle cleaning process performed by pad 444 may
be performed sequentially (e.g., prior to and/or after) with
respect to the edge polishing process performed by polishing pad
480.
[0074] One advantage of the invention is the relatively small size
of the pads 444 and 480 compared to the size of the substrate 100.
Conventional systems use large pads positioned on the polishing
module to clean smaller substrates, where the substrate is in 100
percent contact with the pad. Large pads are prone to trapping
abrasives and particulates, which often cause scratches and defects
in the substrate. However, the smaller pad of the present invention
is significantly less prone to abrasive and particulate trapping,
which advantageously results in a cleaner pad and substrates with
less scratches and defects. Additionally, the smaller pad of the
present invention significantly reduces the cost of consumables,
both in the amount of fluid utilized during processing and the cost
of replacement pads. Furthermore, the smaller pad of the present
invention significantly allows the pad to be easily removed or
replaced.
[0075] Referring back to FIG. 6, once the substrate is cleaned and
the edge of the substrate has been polished, the pad actuation
assemblies 406, 470 retract the pad holders 434, 478 and pads 444,
480 away from the substrate 100 (shown in phantom). The first pad
holder 434 and pad 444 may be moved linearly in a direction
parallel to the X-axis away from the substrate and out of the
internal volume 412 of the housing 402 into a pocket 604 coupled to
the housing 402. Positioning the first pad holder 434 and pad 444
in the pocket 604 as shown in phantom in FIG. 6 and out of the
internal volume 412 of the housing 402 advantageously provides more
space for the robot 268 to enter the housing 402 and transfer the
substrate without risk of damaging either the pad 444 or the
substrate 100, while allowing the housing 402 to be smaller and
less expensive.
[0076] Substrate transfer begins after cleaning by having the
substrate receiver 410 move upward in a direction parallel to the
Y-axis to engage the substrate 100 in the substrate receiving slot
432. Once the substrate is disposed in the substrate receiving slot
432, the substrate holder 414 releases the substrate 100 by turning
off the vacuum provided by the vacuum source 497, and optionally
providing a gas through the apertures 502 of the substrate holder
414 to separate the substrate from the substrate holder 414. The
substrate receiver 410 with the substrate 100 disposed in the
substrate receiving slot 432 is then moved laterally away from the
substrate holder 414 in a direction parallel to the Z-axis to clear
the substrate 100 from the substrate holder 414. One of the
substrate grippers 274, 276 of the robot 268 retrieves the
substrate 100 from the substrate receiver 410 and removes the
substrate 100 from the housing 402. An optional top spray bar 464
and bottom spray bar 466 are positioned across the internal volume
412 and may spray the substrate 100 with deionized water or any
other suitable fluid to clean the substrate 100 as the substrate
100 is removed from the particle cleaning module 282 by the robot
268. At least one of the spray bars 464, 466 may be utilized to wet
the substrate 100 prior to chucking against the substrate receiver
410 to remove particles that may potentially scratch the backside
of the substrate and/or to improve chucking by the substrate
receiver 410. The spray bars 464, 466 may be coupled to different
fluid sources 499, 500 so that different fluids may be provided to
each of the spray bars 464, 466, or both spray bars 464, 466 may be
coupled to a single fluid delivery source.
[0077] Referring back to the planarizing module 206 of FIG. 2, both
of the second and third station 230, 232 may be used to perform CMP
process as the particle cleaning module 282 substantially
eliminates the need for a buffing pad disposed in one of the second
and third stations 230, 232 as required in conventional systems.
Since the second and third station, 230, 232 are to be used for CMP
processes; the use of the particle cleaning module 282
advantageously increases the throughput of the CMP system 200. The
vertical substrate orientation of the particle cleaning module 282
is also beneficial, as it removes particles in a more compact
footprint as compared to traditional horizontal designs utilized on
the polishing module.
[0078] Furthermore, the particle cleaning module 282 effectively
cleans the substrate and decreases the loading of particulate on
the brushes of the first brush module 264B and second brush module
2640. Therefore, the lifespan of the brushes in the first brush
module 264B and second brush module 2640 are advantageously
increased. Thus, the particle cleaning module removes particularly
difficult to remove polishing fluids without requiring a buffing
station in the polishing module and simultaneously frees the second
and or third station for additional CMP stations to increase
throughput of the planarizing system.
[0079] In some implementations, the driver(s) used to rotate the
substrate 100 and the actuator used to push the pads and/or
polishing film against the surface of the substrate or edge of the
substrate edge may be controlled by the controller 208. Likewise,
operation of the fluid delivery nozzles 450, 482 may also be under
the direction of the controller 208. The controller 208 may be
adapted to receive feedback signals from the driver and/or actuator
that indicate: (1) an amount of energy and/or torque being exerted
to drive the substrate 100 (e.g., rotate a vacuum chuck holding the
substrate 100) and/or (2) an amount of force applied to the
actuators to push the pads 444, 480 against the substrate 100,
respectively. These feedback signals may be employed to determine
an amount of material that has been removed from the substrate 100,
which may include, for example, whether a particular layer of
material has been removed and/or whether an intended edge profile
has been reached. For example, a reduction in the torque of the
rotating substrate 100 (or energy expended in rotating the
substrate 100) during a polishing procedure may indicate a
reduction in friction between the substrate 100 and the pad 444,
480. The reduction in torque or rotational energy may correspond to
an amount of material removed from the edge of the substrate 100 at
or near points of contact between the substrate 100 and the pad
444, 480 and/or a characteristic edge profile (e.g., a shape,
curvature or smoothness level at the edge of the substrate
100).
[0080] Alternatively or additionally, a friction sensor positioned
in contact with the edge of the substrate 100 may provide signals
indicative of an amount of material that has been removed from the
edge of the substrate 100.
[0081] In some implementations, the pad 444, 480 may have an
adjustable amount of ability to conform to the substrate's edge. In
certain implementations, the pad material may be selected such that
the pad 444, 480 has an adjustable amount of ability to conform to
the substrate's edge. In certain implementations, the pad 444, 480
may be or include an inflatable bladder such that by adding more
air or liquid or other fluid, the pad becomes harder and by
reducing the amount of air or liquid or other fluid in the bladder,
the pad becomes more conforming. In some implementations, the fluid
supply may inflate/deflate the bladder under the direction of an
operator or a programmed and/or user operated controller. In such
implementations, an elastomeric material such as silicon rubber or
the like may be used for the bladder to further enhance the pad's
ability to stretch and conform to the substrate's edge. Such an
implementation would allow an operator/controller to precisely
control how far beyond the exclusion region 108a and/or 108b and
into the bevels 112, 114 (if at all) (See FIG. 1) the polishing pad
480 is made to contact the substrate 100 by, e.g., limiting the
amount of fluid pumped into the bladder. For example, once a
substrate outer edge 110 is placed against the pad 444 with a
deflated bladder, the bladder may be inflated so that the pad 444
is forced to wrap around and conform to the outer edge 110 and
bevel(s) 112, 114 of the substrate 100 without wrapping around to
the device region 106a, 106b of the substrate 100.
[0082] FIG. 8 is a top schematic view of the particle cleaning
module 282 having a pad conditioning assembly 810 for conditioning
the pad 444 and a zero gap calibration sensor having sensor heads
820a, 820b positioned for detecting the position of the pad 444
disposed therein. The particle cleaning module 282 also includes a
pair of cleaning nozzles 830a and 830b for directing a cleaning
fluid (e.g., DI water) toward various components of the particle
cleaning module 282 and a spray nozzle 840 for directing a cleaning
fluid (e.g., DI water) toward the polishing pad 480 to condition
and remove debris from the polishing pad 480. As depicted in FIG.
11, the second pad actuation assembly 1170 does not move in a
lateral direction like the second pad actuation assembly 470
depicted in FIG. 4.
[0083] The sensor heads 820a, 820b of the zero gap calibration
sensor may be coupled with the controller 208. The zero gap
calibration sensor is configured to detect the position of the pad
444 relative to the surface of the substrate 100.
[0084] FIGS. 9A-9C are schematic views of the first pad actuation
assembly 406 according to implementations described herein. FIGS.
10A-10D are schematic views of the first pad actuation assembly 406
according to implementations described herein.
[0085] FIG. 9A is a partial schematic view of the particle cleaning
module 282 where the pad conditioning assembly 810 includes a high
pressure spray nozzle 905 for directing a cleaning fluid toward the
pad 444 of the first pad actuation assembly 406. The pad
conditioning assembly 810 is positioned adjacent to the substrate
holder 414 such that the first pad actuation assembly 406 may move
laterally along rail 458 to the side of the substrate holder 414
where the pad 444 may be accessed by the pad conditioning assembly
810.
[0086] With reference to FIGS. 9B, 9C, 10B, 10C and 10D, the first
pad actuation assembly 406 includes a first pad holder assembly
910, an adapter 920 for coupling the first pad holder 434 with the
first pad holder assembly 910. The first pad holder assembly 910
may be coupled with a motor shaft 925 of the pad rotation mechanism
436. The first pad holder assembly 910 may be coupled with the pad
rotation mechanism 436 via one or more attachment mechanisms 930,
for example, clamping screws. The adapter 920 may be coupled with
the first pad holder assembly 910 via one or more attachment
mechanisms 940, for example, a locking pin. The first pad holder
434 may be coupled with the adapter 920 via one or more attachment
mechanisms 950, e.g., a locking screw.
[0087] The first pad holder 434 is removable from the adapter 920
for replacement. In order to replace the pad 444, the attachment
mechanism 950 only needs to be loosened and the first pad holder
434 and pad 444 may be removed without removing the first pad
holder assembly 910 and adapter 920. In certain implementations,
the first pad holder assembly 910 is coupled directly with the
first pad holder 434 without the use of an adapter. A force control
mechanism 960 (e.g., a compression spring) may be positioned
between the adapter 920 and the first pad holder 434.
[0088] FIG. 10A is a schematic perspective view of one
implementation of the first pad actuation assembly 406. The first
pad actuation assembly 406 is coupled with the rail 458. As
depicted by arrow 1010, the first pad actuation assembly 406 is
movable along rail 458. The first pad actuation assembly 406 is
also coupled with a second rail 1030 for movement of the first pad
actuation assembly 406 in the direction shown by arrow 1020.
Movement in the direction shown by arrow 1020 allows for the pad
444 to contact the substrate 100 for polishing and cleaning the
substrate and also allows the pad 444 to contact the pad
conditioning assembly 810 for conditioning of the pad 444.
[0089] FIG. 11 is a schematic cross-sectional view of another
implementation of a particle cleaning module 1100 according to
implementations described herein. The particle cleaning module 1100
may be used in place of the particle cleaning module 282 in and of
the previously discussed implementations. Similar to particle
cleaning module 282, particle cleaning module 1100 includes a
housing 1102, a substrate rotation assembly 404, a first pad
actuation assembly 1106 and a second pad actuation assembly 1170.
However, unlike particle cleaning module 282, the first pad
actuation assembly 1106 of particle cleaning module 1100 includes a
rotary arm assembly 1108 and the second pad actuation assembly 1170
is stationary (e.g. does not move laterally along a track like the
second actuation assembly 470.) Although the first pad actuation
assembly 1106 and the second pad actuation assembly 1170 are shown,
it should be understood that the implementations described herein
may be performed with a single pad actuation assembly. For example,
the first pad actuation assembly 1106 and the second pad actuation
assembly 1170 may be positioned in separate housings. The housing
1102 includes an opening (not shown) at a top of the housing and a
substrate receiver 410 at a bottom 1118 of the housing 1102. A
drain 1168 is formed through the bottom 1118 of the housing 1102 to
allow fluids to be removed from the housing 1102. The opening
allows the robot 268 (not shown in FIG. 11) to vertically transfer
the substrate to an internal volume 1112 defined within the housing
1102. The housing 1102 may optionally include a lid 1104 that can
open and close to allow the robot 268 in and out of the housing
1102.
[0090] The substrate receiver 410 has a substrate receiving slot
(not shown in FIG. 11) facing upwards parallel to the Y-axis. The
receiving slot is sized to accept the perimeter of the substrate
100, thereby allowing the one of the substrate grippers 274, 276 of
the substrate handler 266 (See FIG. 3) to place the substrate 100
in the receiving slot in a substantially vertical orientation. The
substrate receiver 410 is coupled to a Z-Y actuator 411. The Z-Y
actuator 411 may be actuated to move the substrate receiver 410
upwards in the Y-axis to align a centerline of the substrate 100
disposed in the substrate receiver 410 with a centerline of the
substrate rotation assembly 404. Once the centerline of the
substrate 100 is aligned with the centerline of the substrate
rotation assembly 404, the Z-Y actuator 411 may be actuated to move
the substrate receiver 410 in the Z-axis to contact the substrate
100 against the substrate rotation assembly 404, which then
actuates to chuck the substrate 100 to the substrate rotation
assembly 404. After the substrate 100 has been chucked to the
substrate rotation assembly 404, the Z-Y actuator 411 may be
actuated to move the substrate receiver 410 in the Y-axis clear of
the substrate 100 and the substrate rotation assembly 404 so that
the substrate 100 held by the substrate rotation assembly 404 may
be rotated without contacting the substrate receiver 410.
[0091] The substrate rotation assembly 404 is disposed in the
housing 1102 and includes a substrate holder 414 coupled to a
substrate rotation mechanism 416. The substrate holder 414 may be
an electrostatic chuck, a vacuum chuck, a mechanical gripper or any
other suitable mechanism for securely holding the substrate 100
while the substrate is rotated during processing within the
particle cleaning module 1100. Preferably, the substrate holder 414
is either an electrostatic chuck or a vacuum chuck.
[0092] The first pad actuation assembly 1106 includes the pad
rotation mechanism 436, a pad cleaning head 438, and the rotary arm
assembly 1108. The pad cleaning head 438 is located in the internal
volume 1112 of the housing 1102 and includes the first pad holder
434 that holds the pad 444 and a fluid delivery nozzle 450. The
fluid delivery nozzle 450 is coupled to a fluid delivery source 498
that provides deionized water, a chemical solution or any other
suitable fluid to the pad 444 during cleaning the substrate
100.
[0093] The first pad holder 434 (and pad 444) has a diameter much
less than that of the substrate 100, for example at least less than
half the diameter of the substrate or even as much as less than
about one eighth the diameter of the substrate. In one
implementation, the first pad holder 434 (and pad 444) may have a
diameter of less than about 25 mm. The first pad holder 434 may
hold the pad 444 utilizing clamps, vacuum, adhesive or other
suitable technique that allows for the pad 444 to periodically be
replaced as the pad 444 becomes worn after cleaning a number of
substrates 100.
[0094] The pad 444 may be fabricated from a polymer material, such
as porous rubber, polyurethane and the like, for example, a
POLYTEX.TM. pad available from Rodel, Inc. of Newark, Del. In one
implementation, the first pad holder 434 may be used to a hold a
brush or any other suitable cleaning device. The first pad holder
434 is coupled to the pad rotation mechanism 436 by a second shaft
446. The second shaft 446 is oriented parallel to the Z-axis and
extends from the internal volume 1112 through an elongated slit
formed through the housing 402 to the pad rotation mechanism 436.
The pad rotation mechanism 436 may be an electrical motor, an air
motor, or any other suitable motor for rotating the first pad
holder 434 and pad 444 against the substrate. The pad rotation
mechanism 436 is coupled to the controller 208. In one
implementation, the pad rotation mechanism 436 rotates the first
pad holder 434 (and pad 444) at a rate of at least about 1000
rpm.
[0095] The pad rotation mechanism 436 is coupled to bracket 454 by
an axial actuator 440. The axial actuator 440 is coupled to the
controller 208 or other suitable controller and is operable to move
the first pad holder 434 along the Z-axis to move the pad 444
against and clear of the substrate 100 held by the substrate holder
414. The axial actuator 440 may be a pancake cylinder, linear
actuator or any other suitable mechanism for moving the first pad
holder 434 in a direction parallel to the Z-axis. In operation,
after the substrate holder 414 is in contact with and holding the
substrate, the axial actuator 440 drives the first pad holder 434
in a z-direction to make contact with the substrate 100.
[0096] The rotary arm assembly 1108 includes a rotary arm 1180, a
rotary arm rotation motor 1150, a lateral actuator mechanism 1182
for moving the rotary arm 1180 toward the substrate 100. The
lateral actuator mechanism 1182 may comprise a disk pad arm in/out
cylinder coupled 1184 with a spring 1186 for force control and
damping.
[0097] The second pad actuation assembly 1170 includes a pad
rotation mechanism 472, and a pad polishing head 474. The pad
polishing head 474 is located in the internal volume 1112 of the
housing 1102 and includes the second pad holder 478 that holds a
pad 480 and a fluid delivery nozzle 482. The fluid delivery nozzle
482 is coupled to a fluid delivery source 484 that provides
polishing slurry, deionized water, a chemical solution or any other
suitable fluid to the pad 480 during polishing of the exclusion
region and/or edge region of the substrate 100.
[0098] A centerline of the second pad holder 478 may be aligned
with the edge of the substrate 100. The second pad holder 478 (and
polishing pad 480) has a diameter much less than that of the
substrate 100, for example at least less than half the diameter of
the substrate or even as much as less than about one eighth the
diameter of the substrate. In one implementation, the second pad
holder 478 (and polishing pad 480) may have a diameter of less than
about 50 mm. The second pad holder 478 may hold the polishing pad
480 utilizing clamps, vacuum, adhesive or other suitable techniques
that allow for the polishing pad 480 to periodically be replaced as
the polishing pad 480 becomes worn after polishing the edge of a
number of substrates 100.
[0099] The polishing pad 480 may be fabricated from a polymer
material, such as porous rubber, polyurethane and the like, for
example, a POLYTEX.TM. pad available from Rodel, Inc. of Newark,
Del. The polishing pad 480 may be a fixed abrasive pad. The second
pad holder 478 is coupled to the pad rotation mechanism 472 by a
third shaft 486. The third shaft 486 is oriented parallel to the
Z-axis and extends from the internal volume 1112 through an
elongated slit formed through the housing 1102 to the pad rotation
mechanism 472. The pad rotation mechanism 472 may be an electrical
motor, an air motor, or any other suitable motor for rotating the
second pad holder 478 and polishing pad 480 against the substrate
100. The pad rotation mechanism 472 is coupled to the controller
208. In one implementation, the pad rotation mechanism 472 rotates
the second pad holder 478 (and polishing pad 480) at a rate of at
least about 1000 rpm.
[0100] The pad rotation mechanism 472 is coupled to bracket 488 by
an axial actuator 490. The axial actuator 490 is coupled to the
controller 208 or other suitable controller and is operable to move
the second pad holder 478 along the Z-axis to move the polishing
pad 480 against and clear of the substrate 100 held by the
substrate holder 414. The axial actuator 490 may be a pancake
cylinder, linear actuator or any other suitable mechanism for
moving the second pad holder 478 in a direction parallel to the
Z-axis. In operation, after the substrate holder 414 is in contact
with and holding the substrate, the axial actuator 490 drives the
second pad holder 478 in a z-direction to make contact with the
substrate 100.
[0101] Scanning the pad 444 across the substrate 100 in the
particle cleaning module 1100 has effectively demonstrated the
ability to effectively remove particles, such as abrasives from the
polishing fluid, from the surface of the substrate 100. Further,
scanning the polishing pad 480 across the exclusion region and/or
edge region has demonstrated the ability to effectively remove
particles, such as abrasives, excess deposited material, and/or
polishing slurry from the surface of the substrate 100, for
example, the exclusion region and/or edge region of the substrate.
Thus, the inclusion of a polishing step at the wafer edge in
addition to particle cleaning has effectively demonstrated edge
defect improvement. Accordingly, the need for a dedicated buffing
station on the polishing module is substantially eliminated.
[0102] FIG. 12 is a cross-sectional schematic view of another
implementation of a disk pad holder according to implementations
described herein.
[0103] FIG. 13 is another schematic view of the particle cleaning
module 1100 of FIG. 11 according to implementations described
herein. FIG. 13 depicts the sweep motion of the rotary arm 1180
along a curved path as shown by arrow 1310.
[0104] FIG. 14 is another schematic view of the particle cleaning
module 1100 of FIG. 11 according to implementations described
herein. FIG. 14 depicts the sweep motion of the rotary arm 1180 and
the attached pad 444 along arrow 1310 to interact with the pad
conditioning assembly 810 and pad clean spray nozzle 1402 for
delivering a cleaning fluid (e.g., DI water) to surface of the pad
444. A sensor 1404 for detecting the presence of substrate 100 is
positioned on the substrate receiver 410.
[0105] FIG. 15 is a schematic view of a portion of a particle
cleaning module illustrating another implementation of the pad
conditioning assembly 810 according to implementations described
herein. The pad conditioning assembly 810 includes a conditioning
pad actuation assembly 1570 for rotating a conditioning pad 1580
and moving the conditioning pad 1580 in an axial direction 1504
toward the pad to be conditioned. The conditioning pad 1580 may be
a conditioning disk. The conditioning pad actuation assembly 1570
includes a pad rotation mechanism 1572 and a pad polishing head
1574. The pad polishing head 1574 is located in the internal volume
1112 of the housing 1102 and includes a pad holder 1578 that holds
the conditioning pad 1580 and a fluid delivery nozzle 1502. The
fluid delivery nozzle 1502 is coupled to a fluid delivery source
1584 that provides polishing slurry, deionized water, a chemical
solution or any other suitable fluid to the conditioning pad 1580
during conditioning of the pad 444.
[0106] FIG. 16 is a schematic view of another implementation of an
edge pad polishing assembly 1600 according to implementations
described herein. The edge pad polishing assembly 1600 may be used
in place of either the second pad actuation assembly 470 or the
second pad actuation assembly 1170. The edge pad polishing assembly
1600 is adjustable between 1 and 10 degrees as shown by arrow 1602,
which provides better access to the edge of substrate 100 for
improved cleaning.
[0107] The edge pad polishing assembly 1600 includes a pad rotation
mechanism 1672, a pad polishing head 1674 and an axial actuator
mechanism 1690. The pad polishing head 1674 is located in the
internal volume 1112 of the housing 1102 and includes an edge pad
holder 1678 that holds a polishing pad 1680 and a fluid delivery
nozzle. The fluid delivery nozzle is coupled to a fluid delivery
source that provides polishing slurry, deionized water, a chemical
solution or any other suitable fluid to the polishing pad 1680
during polishing of the exclusion region and/or edge region of the
substrate 100.
[0108] A centerline of the edge pad holder 1678 may be aligned with
the edge of the substrate 100. The edge pad holder 1678 (and
polishing pad 1680) has a diameter much less than that of the
substrate 100, for example at least less than half the diameter of
the substrate or even as much as less than about one eighth the
diameter of the substrate. In one implementation, the edge pad
holder 1678 (and polishing pad 1680) may have a diameter of less
than about 50 mm. The edge pad holder 1678 may hold the polishing
pad 1680 utilizing clamps, vacuum, adhesive or other suitable
techniques that allow for the polishing pad 1680 to periodically be
replaced as the polishing pad 1680 becomes worn after polishing the
edge of a number of substrates 100.
[0109] The polishing pad 1680 may be fabricated from a polymer
material, such as porous rubber, polyurethane and the like, for
example, a POLYTEX.TM. pad available from Rodel, Inc. of Newark,
Del. The polishing pad 1680 may be a fixed abrasive pad. The edge
pad holder 1678 is coupled to the pad rotation mechanism 1672 by a
shaft 1686. The pad rotation mechanism 1672 may be an electrical
motor, an air motor, or any other suitable motor for rotating the
edge pad holder 1678 and polishing pad 1680 against the substrate
100. The pad rotation mechanism 1672 is coupled to the controller
208. In one implementation, the pad rotation mechanism 1672 rotates
the edge pad holder 1678 (and polishing pad 1680) at a rate of at
least about 1000 rpm.
[0110] The pad rotation mechanism 1672 may be coupled to a bracket
(not shown) by an axial actuator 1690. The axial actuator 1690 is
coupled to the controller 208 or other suitable controller and is
operable to move the edge pad holder 1678 along the Z-axis to move
the polishing pad 1680 against the edge of the substrate 100 held
by the substrate holder 414. The axial actuator 1690 may be a
pancake cylinder, linear actuator or any other suitable mechanism
for moving the edge pad holder 1678 in a direction parallel to the
Z-axis. In operation, after the substrate holder 414 is in contact
with and holding the substrate, the axial actuator 1690 drives the
edge pad holder 1678 in a z-direction to make contact with the
substrate 100.
[0111] While the foregoing is directed to implementations of the
present invention, other and further implementations of the
invention may be devised without departing from the basic scope
thereof, and the scope thereof is determined by the claims that
follow.
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