U.S. patent application number 12/245765 was filed with the patent office on 2009-02-05 for methods and apparatus for processing a substrate.
This patent application is currently assigned to APPLIED MATERIALS, INC.. Invention is credited to Liang-Yuh Chen, Gary C. Ettinger, Wei-Yung Hsu, Sen-Hou Ko, Donald Olgado, Ho Seon Shin, Erik C. Wasinger.
Application Number | 20090036033 12/245765 |
Document ID | / |
Family ID | 38138234 |
Filed Date | 2009-02-05 |
United States Patent
Application |
20090036033 |
Kind Code |
A1 |
Wasinger; Erik C. ; et
al. |
February 5, 2009 |
METHODS AND APPARATUS FOR PROCESSING A SUBSTRATE
Abstract
A method of cleaning an edge of a substrate is provided. The
method comprises tensioning a first polishing film in a frame;
contacting the first polishing film against an edge of a substrate;
conforming the first polishing film to the edge of the substrate,
the edge including an outer edge and at least one bevel; and
rotating the substrate while the first polishing film remains in
contact with the substrate. Numerous other aspects are
provided.
Inventors: |
Wasinger; Erik C.;
(Naperville, IL) ; Ettinger; Gary C.; (Cupertino,
CA) ; Ko; Sen-Hou; (Sunnyvale, CA) ; Hsu;
Wei-Yung; (Santa Clara, CA) ; Chen; Liang-Yuh;
(Foster City, CA) ; Shin; Ho Seon; (Cupertino,
CA) ; Olgado; Donald; (Palo Alto, CA) |
Correspondence
Address: |
DUGAN & DUGAN, PC
245 Saw Mill River Road, Suite 309
Hawthorne
NY
10532
US
|
Assignee: |
APPLIED MATERIALS, INC.
Santa Clara
CA
|
Family ID: |
38138234 |
Appl. No.: |
12/245765 |
Filed: |
October 5, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11299295 |
Dec 9, 2005 |
|
|
|
12245765 |
|
|
|
|
Current U.S.
Class: |
451/44 ; 451/57;
451/60 |
Current CPC
Class: |
B24B 21/004 20130101;
B24B 9/065 20130101; H01L 21/02021 20130101; C03C 19/00 20130101;
B24B 1/04 20130101 |
Class at
Publication: |
451/44 ; 451/60;
451/57 |
International
Class: |
B24B 1/04 20060101
B24B001/04; B24B 9/00 20060101 B24B009/00 |
Claims
1. A method of cleaning an edge of a substrate comprising:
tensioning a first polishing film in a frame; contacting the first
polishing film against an edge of a substrate; conforming the first
polishing film to the edge of the substrate, the edge including an
outer edge and at least one bevel; and rotating the substrate while
the first polishing film remains in contact with the substrate.
2. The method of claim 1 further comprising: delivering a fluid to
the edge of the substrate.
3. The method of claim 2 wherein delivering the fluid further
comprises: applying at least one of water and a cleaning chemistry
to the edge of the substrate via an inflatable pad.
4. The method of claim 2 wherein delivering the fluid further
comprises: applying at least one of water and a cleaning chemistry
to the edge of the substrate via the first polishing film.
5. The method of claim 1 further comprising: conforming a second
polishing film to the edge of the substrate.
6. The method of claim 5 wherein the second polishing film includes
a different type of polishing film compared to the first polishing
film.
7. The method of claim 6 wherein the first and second polishing
films contact the edge of the substrate one of sequentially and
simultaneously.
8. The method of claim 1 further comprising: delivering fluid
including sonic energy to the edge of the substrate.
9. The method of claim 1 further comprising: rotating the substrate
for between 5 and 150 seconds.
10. The method of claim 1 wherein the frame includes one or more
heads adapted to conform the first polishing film to the edge of
the substrate.
11. The method of claim 10 further comprising: angularly
translating the one or more heads and the first polishing film
around an axis tangential to the outer edge of the substrate.
12. The method of claim 10 further comprising: circumferentially
rotating, with respect to the substrate, the one or more heads
around the edge of the substrate.
13. The method of claim 1 further comprising: advancing the first
polishing film as it contacts the substrate edge.
14. The method of claim 10 wherein conforming the first polishing
film further comprises: pressing a conformable pad portion of the
head against the first polishing film.
15. The method of claim 14 further comprising: adjusting the
pressure applied by the conformable pad against the first polishing
film.
16. The method of claim 15, wherein the pressure is adjusted by a
controller based on a signal.
17. The method of claim 10 further comprising: oscillating the one
or more heads between positions that allow the first polishing film
to contact at least one bevel and the outer edge of the
substrate.
18. The method of claim 10 further comprising: controlling the
movement of the one or more heads with a controller.
19. The method of claim 10 further comprising: polishing a
predefined portion of the edge of the substrate with the one or
more heads.
20. The method of claim 1 further comprising: moving the edge of
the substrate in a longitudinal direction; and spanning the first
polishing film between a supply spool and a take up spool in a
longitudinal direction.
Description
[0001] This application is a division of, and claims priority to,
U.S. Non-Provisional patent application Ser. No. 11/299,295, filed
Dec. 9, 2005, and titled, "METHODS AND APPARATUS FOR PROCESSING A
SUBSTRATE" (Attorney Docket No. 10121), which is hereby
incorporated by reference herein in its entirety for all
purposes.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] The present invention is related to U.S. patent application
Ser. No. 11/298,555 filed on Dec. 9, 2005 and entitled "METHODS AND
APPARATUS FOR PROCESSING A SUBSTRATE" (Attorney Docket No. 10414)
which is hereby incorporated herein by reference for all
purposes.
FIELD OF THE INVENTION
[0003] The present invention relates generally to substrate
processing, and more particularly to methods and apparatus for
cleaning an edge of a substrate.
BACKGROUND
[0004] Conventional systems, which contact a substrate edge with an
abrasive film to clean the edge, may not thoroughly clean the edge.
For example, the abrasive film may not sufficiently contact both
bevels of the edge during cleaning. Additionally, the abrasive film
may become worn from use, and therefore, lose its ability to
sufficiently clean the substrate and require frequent replacement,
which may affect semiconductor device manufacturing throughput.
Accordingly improved methods and apparatus for cleaning an edge of
a substrate are desired.
SUMMARY OF THE INVENTION
[0005] In a first aspect of the invention, an apparatus adapted to
polish an edge of a substrate includes a polishing film, a frame
adapted to tension the polishing film so that at least a portion of
the film is supported in a plane, and a substrate rotation driver
adapted to rotate a substrate against the plane of the polishing
film such that the polishing film is adapted to apply tension to
the substrate, contour to an edge of the substrate which includes
at least an outer edge and a first bevel, and polish the outer edge
and the first bevel as the substrate is rotated.
[0006] In a second aspect of the invention an apparatus adapted to
polish an edge of a substrate includes a plurality of polishing
films, a frame adapted to tension each of the polishing films so
that at least a portion of each of the films are supported in a
respective plane, and a substrate rotation driver adapted to rotate
a substrate against at least one of the respective planes of the
polishing films such that any polishing films contacting the
substrate apply pressure to the substrate, contour to an edge of
the substrate, and polish the edge as the substrate is rotated.
[0007] In a third aspect of the invention an apparatus adapted to
polish an edge of a substrate includes a polishing film having a
polishing side and a second side, an inflatable pad disposed
adjacent the second side of the polishing film, a frame adapted to
support the polishing film and the inflatable pad, and a substrate
rotation driver adapted to rotate a substrate against the polishing
side of the polishing film. The polishing film is disposed between
an edge of the substrate and the inflatable pad so that the
inflatable pad and polishing film contour to the edge of the
substrate and the polishing film contacts the edge of the
substrate.
[0008] In a fourth aspect of the invention a method of cleaning an
edge of a substrate includes (a) supporting a polishing film, (b)
conforming the polishing film to an edge of a substrate, the edge
including an outer edge and at least one bevel, and (c) rotating
the substrate.
[0009] Other features and aspects of the present invention will
become more fully apparent from the following detailed description,
the appended claims and the accompanying drawings.
BRIEF DESCRIPTION OF THE FIGURES
[0010] FIG. 1 is a schematic illustration of a cross-section of a
portion of a substrate.
[0011] FIG. 2 is a schematic illustration depicting an example
embodiment of an edge cleaning apparatus according to the present
invention.
[0012] FIGS. 3A and 3B are close-up front and side cross-sectional
schematic views, respectively, of a portion of the edge cleaning
apparatus of FIG. 2.
[0013] FIG. 4 is a perspective view depicting an example embodiment
of an edge cleaning apparatus according to the present
invention.
[0014] FIG. 5 is a perspective view depicting another example
embodiment of an edge cleaning apparatus according to the present
invention.
[0015] FIG. 6 is a perspective view of a portion of the example
embodiment depicted in FIG. 5.
[0016] FIGS. 7A and 7B are close-up perspective views of different
embodiments of replaceable cassettes for use with embodiments of
the present invention.
[0017] FIGS. 8A through 8C are close-up perspective views of
different embodiments of pads for use with embodiments of the
present invention.
[0018] FIGS. 9A through 9C are plan views of examples of different
possible head positions of the example edge polishing apparatus of
FIG. 4.
[0019] FIGS. 10A through 10C are plan views of examples of
different possible head positions of the example edge polishing
apparatus of FIG. 5.
[0020] FIG. 11 is a perspective view of an embodiment of a multiple
head edge polishing apparatus according to the present
invention.
[0021] FIG. 12 is a perspective view of another embodiment of a
multiple head edge polishing apparatus according to the present
invention.
[0022] FIG. 13 is a perspective view of yet another embodiment of a
multiple head edge polishing apparatus according to the present
invention.
DETAILED DESCRIPTION
[0023] The present invention provides improved methods and
apparatus for cleaning and/or polishing the edge of a substrate.
With reference to FIG. 1, a substrate 100 may include two major
surfaces 102, 102' and an edge 104. Each major surface 102, 102' of
the substrate 100 may include a device region 106, 106' and an
exclusion region 108, 108'. (Typically however, only one of the two
major surfaces 102, 102' will include a device region and an
exclusion region.) The exclusion regions 108, 108' may serve as
buffers between the device regions 106, 106' 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 108, 108' of the two major
surfaces 102, 102'. 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 106, 106'. In
some embodiments, all or part of the exclusion regions 108, 108'
may be cleaned or polished as well.
[0024] The present invention provides a frame for supporting a film
(e.g., an abrasive polishing film) or abrasive buffer against the
edge 104 of a substrate 100 as the substrate 100 is rotated (e.g.,
by a vacuum chuck, drive rollers, etc.). The film may be pressed
against the rotating substrate edge 104 using a pad pushed by an
actuator and/or an inflatable pad. In either case, the pad and/or
inflatable pad may be soft and/or include or develop contours to
conform with the shape of the substrate edge 104. Depending on the
amount of force applied by the actuator, the resiliency of the pad
selected, the amount of inflation of an inflatable pad, and/or the
amount of tension on the film, a controlled amount of pressure may
be applied to polish the edge 104. Alternatively or additionally,
the film may be under tension within the frame such that the film
itself is adapted to apply a variable amount of tension to the
substrate edge 104 and to contour to both the outer edge 110 and at
least one of the bevels 112, 114 (e.g., with or without additional
support from a pad). Thus, the present invention provides precise
control of an edge polish process which may be used to compensate
for different edge geometries and changes in the substrate 100 as
material is removed from the edge 104.
[0025] In some embodiments, the frame may support multiple heads,
each head being adapted to support polishing film. The heads may
support different types of films (e.g., films of different abrasive
grits) which may be used concurrently, in a predefined sequence, or
at different times. The heads may be disposed in different
positions to allow the supported films to polish different portions
of the edge 104 of the rotating substrate 100. The heads may be
adapted to be moved (e.g., angularly translated about a tangential
axis of the substrate 100 and/or circumferentially relative to the
substrate 100) around the edge 104 by the frame so as to polish
different portions of the edge 104. In some embodiments, the heads
may continuously oscillate around the rotating edge 104 of the
substrate 100. Each head may include an indexed spool of film
and/or be contained in a replaceable cassette.
[0026] Additionally or alternatively, the present invention may
include facilities to deliver fluids to the substrate edge 104
being polished. In some embodiments, one or more channels may be
provided to direct chemicals or water to the substrate edge 104 to
assist in the polishing and/or to wash away particles resulting
from the polishing. The chemicals may be sprayed directly onto the
substrate 100, at the substrate/polishing film interface, and/or
may be applied to and/or through the film and/or pad. The fluids
may be sprayed from either or both sides of the substrate 100 and
the present invention may employ gravity or suction to cause the
runoff not to contaminate or contact other parts of the substrate
100 or apparatus of the invention. Further, energy (e.g., megasonic
energy) may be applied to the substrate edge 104 via fluid carrying
such energy.
[0027] The substrate 100 may be rotated in a horizontal plane. In
additional or alternative embodiments, the substrate 100 may be
rotated in a vertical plane, other non-horizontal plane, and/or be
moved between different planes of rotation.
[0028] Turning to FIG. 2, a schematic view of an edge polishing
apparatus 200 is depicted. A frame 202 supports and tensions a
polishing film 204 in a plane perpendicular to the major surfaces
102, 102' of a substrate 100 such that the edge 104 of the
substrate 100 may be pressed against (e.g., as indicated by the
straight downward arrows 205a, 205b) the polishing film 204 and the
polishing film 204 may contour to the substrate edge 104. As
indicated by the curved arrow 205c, the substrate 100 may be
rotated against the polishing film 204. The substrate 100 may be
rotated at a rate ranging from about 50 to 300 RPM, for example,
although other rates may be used. The substrate 100 may contact the
polishing film 204 for about 15 to 150 seconds depending on the
type of film used, the grit of the film, the rate of rotation, the
amount of polishing required, etc. More or less time may be used.
In some embodiments, the polishing film 204 may be supported by a
pad 206 disposed adjacent a backside (e.g., a non-abrasive side) of
the polishing film 204 and mounted on the frame 202. As indicated
by the straight upward pointing arrow 207, the frame 202 including
the tensioned polishing film 204 and/or the pad 206 may be pushed
against the edge 104 of the substrate 100. In some embodiments, the
substrate may be pushed against the polishing film with an amount
of force ranging from about 0.5 lbs. to about 2.0 lbs. Other
amounts of force may be used.
[0029] Additionally or alternatively, an additional length of the
polishing film 204 may be supported and tensioned by spools 208,
210 mounted to the frame 202. A supply spool 208 may include unused
polishing film 204 available to be unwound and pulled into position
adjacent the substrate 100 while a take-up spool 210 may be adapted
to receive used and/or worn polishing film 204. One or both of the
spools 208, 210 may be indexed to precisely control the amount of
polishing film 204 that is advanced. The polishing film 204 may be
made from many different materials including aluminum oxide,
silicon oxide, silicon carbide, etc. Other materials may also be
used. In some embodiments, the abrasives used may range from about
0.5 microns up to about 3 microns in size although other sizes may
be used. Different widths ranging from about 1 inch to about 1.5
inches may be used (although other widths may be used). In one or
more embodiments, the polishing film may be about 0.002 to about
0.02 of an inch thick and be able to withstand about 1 to 5 lbs. of
tension in embodiments that use a pad 206 and from about 3 to about
8 lbs. of tension in embodiments without a pad. Other films having
different thicknesses and strengths may be used. The spools 208,
210 may be approximately 1 inch in diameter, hold about 500 inches
of polishing film 204, and may be constructed from any practicable
materials such as polyurethane, polyvinyl difloride (PVDF), etc.
Other materials may be used. The frame 202 may be constructed from
any practicable materials such as aluminum, stainless steel,
etc.
[0030] In some embodiments, one or more fluid channels 212 (e.g., a
spray nozzle or bar) may be provided to deliver chemicals and/or
water to aid in the polishing/cleaning of the substrate edge 104,
lubricate the substrate, and/or to wash away removed material. The
fluid channel 212 may be adapted to deliver fluid to the substrate
100, to the polishing film 204, and/or to the pad 206. The fluids
may include deionized water which may serve as a lubricant and to
flush particles away. A surfactant and/or other known cleaning
chemistries may also be included. In some embodiments, sonic (e.g.,
megasonic) nozzles may be used to deliver sonicated fluids to the
substrate edge 104 to supplement the cleaning. Fluid also may be
delivered through the polishing film 204 and/or pad 206 to the edge
104.
[0031] Turning to FIGS. 3A and 3B, close-up front and side
cross-sectional schematic views, respectively, of the polishing
film 204 and pad 206 of FIG. 2 are depicted. Note that the forces
(indicated by the straight arrows) cause the polishing film 204 and
the pad 206 to contour and conform to the edge 104 of the substrate
100. In some embodiments, if the substrate 100 was not present, the
pad 206 would have a flat surface where the substrate 100 is shown
compressing the pad 206. Likewise, if the substrate 100 was not
present, the polishing film 204 would lie flat and be represented
by a straight line in both views.
[0032] Turning now to FIGS. 4 and 5, two additional alternative
embodiments of an edge polishing apparatus 400, 500 are depicted.
As shown in FIG. 4, an example edge polishing apparatus 400 may
include a base or frame 402 that includes a head 404 which supports
polishing film 204 tensioned between spools 208, 210 and further
supported by a pad 206. As shown, the pad 206 may by mounted to the
head 404 via a biasing device 406 (e.g., a spring). The edge
polishing apparatus 400 of FIG. 4 also may include one or more
drive rollers 408 (two shown) and guide rollers 410 (two shown)
that are adapted to rotate the edge 104 of the substrate 100
against the polishing film 204. The drive rollers 408 may
themselves each be driven by drivers 412 (e.g., motors, gears,
belts, chains, etc.).
[0033] The drive rollers 408 and guide rollers 410 may include a
groove that allows the rollers 408, 410 alone to support the
substrate 100. In some embodiments the groove within the drive
rollers 408 may have a diameter of approximately 2.5 inches and the
groove within the guide rollers 410 may have a diameter of
approximately 1 inch. Other dimensions are possible. The area of
the drive rollers 408 in contact with the substrate 100 may include
texturing or cross-grooves to allow the drive rollers 408 to grip
the substrate 100. The drive rollers 408 and guide rollers 410 may
be constructed from materials such as polyurethane, polyvinyl
difloride (PVDF), etc. Other materials may be used.
[0034] As shown in FIG. 5, another example edge polishing apparatus
500 may include a base or frame 502 that includes a head 504 which
supports polishing film 204 tensioned between spools 208, 210 and
further supported by a pad 206. As shown, the pad 206 may by
mounted to the head 504 via an actuator 506 (e.g., a pneumatic
slide, hydraulic ram, servo motor driven pusher, etc.). The edge
polishing apparatus 500 of FIG. 5 also may include a vacuum chuck
508 coupled to a driver 510 (e.g., motor, gear, belt, chain, etc.).
An advantage of the embodiment depicted in FIG. 5 is that the
apparatus 500 does not need to contact the edge 104 being polished.
Thus, the potential of particles accumulating on drive rollers and
being re-deposited on the edge 104 is eliminated. The need to clean
rollers also is eliminated. Further, the possibility of rollers
damaging or scratching the edge is also eliminated. By holding the
substrate in a vacuum chuck, high speed rotation without vibration
may be achieved.
[0035] Turning now to FIGS. 6 through 8B, some details of features
of the example embodiments of FIGS. 4 and 5 are described. Note
that features from the different embodiments may be combined in
many different practicable ways to serve different design
principals or concerns.
[0036] FIG. 6 depicts details of the frame 502 including the head
504 of FIG. 5. As described above, a head 504 supports polishing
film 204 tensioned between spools 208, 210. The frame 502 (that
includes head 504) may be adapted to be angularly translated
(relative to an axis that is tangential to the edge 104 of a
substrate 100 held in the edge polishing apparatus 500 (FIG. 5)) by
a driver 600 (e.g., a servo motor) and pivot 602. The angular
translation of the frame (and polishing film 204) is described in
more detail below with respect to FIGS. 9A through 10C.
[0037] Additionally, the spools 208, 210 that are mounted to the
head 504, may be driven by one or more drivers 604 (e.g., servo
motors). The drivers 604 may provide both an indexing capability to
allow a specific amount of unused polishing film 204 to be advanced
or continuously fed to the substrate edge, and a tensioning
capability to allow the polishing film to be stretched taught and
to apply pressure to the substrate edge.
[0038] As can more clearly be seen in FIG. 6 (as compared to FIG.
5), the optional pad 206 may by mounted to the head 504 via an
actuator 506 that is adapted to adjustably press and contour the
polishing film 204 against a substrate edge 104 (FIG. 5). Further,
one or more support rollers 606 may also be mounted to the head 504
to guide and align the polishing film 204 in a plane perpendicular
to the major surface 102 (FIG. 1) of a substrate 100 held in the
edge polishing apparatus 500 (FIG. 5).
[0039] Note that in the embodiment depicted in FIGS. 5 and 6, the
length of the polishing film 204 is disposed orthogonal to the edge
104 of a substrate 100 being polished. This is in contrast to the
embodiment depicted in FIG. 2, wherein the longitudinal direction
of the polishing film 204 is aligned with the edge 104 of a
substrate 100 being polished. Other polishing film orientations and
configurations may be employed. For example, the polishing film 204
may be held diagonally relative to the major surface 102 of the
substrate 100.
[0040] Turning to FIGS. 7A and 7B, close-up perspective views of
two different embodiments of replaceable cassettes 700A, 700B are
depicted. Cassettes 700A, 700B may be adapted to provide the
features of the head 404 and polishing film 204 in a disposable,
refillable, and/or replaceable package which may be quickly and
easily mounted on and/or removed from the frames 402, 502 of
different edge polishing apparatuses 400, 500.
[0041] As shown in FIG. 7A, the cassette 700A may include head 404
which supports polishing film 204 which spans from supply reel 208
to take-up reel 210. The polishing film 204 may be guided and
aligned by support rollers 606 mounted to the head 404. A pad 206
may be provided to further support the polishing film 204 as
described above. Also as described above, a biasing device 406
(e.g., a spring) may be employed to mount the pad 206 to the head
404 to provide flexible/dynamic counter-pressure to the pad 206.
Alternatively or additionally, an adjustable actuator 506 (FIG. 6)
may be used to push the pad 206 against the polishing film 204 or
to push the entire head 404 toward the substrate 100.
[0042] In yet another alternative embodiment, as shown in FIG. 7B,
instead of a pad 206, the head 404 may simply rely on the tension
of the polishing film 204 to provide lateral pressure to the
substrate edge 104 (FIG. 1). In some embodiments, the head 404 may
include a notch 702 as shown in FIG. 7B to accommodate the
substrate 100.
[0043] Turning to FIGS. 8A and 8B, two different alternative
embodiments of pads 206A, 206B are depicted. In addition to a pad
206 (FIG. 6) that has a flat surface co-planar with the polishing
film 204 when a substrate is not present, a pad 206A may include a
concave surface that matches the contour of the edge 104 of a
substrate 100. Alternatively, as shown in FIG. 8B, the pad 206B may
include a double concave surface to better match the contour of the
edge 104 of a substrate 100. In yet other alternative embodiments,
a pad 206 may include a shaped groove that precisely matches the
contour of the edge 104 of a substrate 100 including the bevels
112, 114 and outer edge 110 (FIG. 1).
[0044] The pads 206, 206A, 206B may be made of material such as,
for example, an acetal resin (e.g., Delrin.RTM. manufactured by
DuPont Corporation), PVDF, polyurethane closed cell foam, silicon
rubber, etc. Other materials may be used. Such materials may have a
resilience or an ability to conform that is a function of the
thickness or density of the pad. The material may be selected based
upon its resilience. The desired resilience may be selected based
upon the type of polishing required.
[0045] In some embodiments, the pad 206, 206A, 206B may have an
adjustable amount of ability to conform to the substrate's edge.
For example the pad 206, 206A, 206B 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. FIG.
8C depicts an embodiment of a pad 206C that includes an inflatable
bladder 802 that may be filled (and/or emptied) via a fluid channel
804 with fluid from a fluid supply 806. In some embodiments, the
fluid supply 806 may inflate/deflate the bladder 802 under the
direction of an operator or a programmed and/or user operated
controller. In such embodiments, an elastomeric material such as
silicon rubber or the like, may be used for the bladder 802 to
further enhance the pad's ability to stretch and conform to the
substrate's edge 104. Such an embodiment would allow an
operator/controller to precisely control how far beyond the bevels
112, 114 (if at all) and into the exclusion region 108 and/or 108'
(FIG. 1) the polishing film 204 is made to contact the substrate
100 by, e.g., limiting the amount of fluid pumped into the bladder
802. For example, once a substrate outer edge 110 is placed against
a pad 206C with a deflated bladder 802, the bladder 802 may be
inflated so that the pad 206C 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 106, 106' of the
substrate 100. Note that in some embodiments, multiple bladders may
be used in a pad and that differently shaped inflatable bladders
may be used within differently shaped pads 206, 206A, 206B.
[0046] In some embodiments, fluids used to aid in the polishing may
be delivered to the substrate edge via the pads 206, 206A, 206B. A
fluid channel may be provided to drip or spray the fluid on or into
the pads. Alternatively, an inflatable pad may include a bladder
with a semi-permeable membrane that allows fluid to be slowly
released and transmitted to the polishing film 204 (e.g., through
the pad). In such embodiments, the pads 206, 206A, 206B may be
covered by, made of, and/or include material that absorbs and/or
retains the fluids used (e.g., polyvinyl alcohol (PVA), etc.).
[0047] FIGS. 9A through 9C and FIGS. 10A through 10C depict
examples of different possible head positions of the alternative
edge polishing apparatuses 400, 500 respectively, described above.
The present invention is adapted to bring polishing film 204 in
contact with the bevels 112, 114, and outer edge 110 of a substrate
100 without contacting the device region 106 of the substrate 100.
In operation, this is achieved by angularly translating a head 404,
504 (and consequently, a portion of polishing film in contact with
and contoured to the edge 104 of a substrate 100) around an axis
that is tangential to the outer edge 110 of the substrate 100 as it
is rotated. Referring to FIGS. 9A through 9C and FIGS. 10A through
10C, this axis of angular translation may be represented by a line
extending perpendicular out of the paper upon which the FIGs. are
drawn at the point labeled "P." The heads 404, 504 may be held in
various positions to clean desired portions of the substrate edge
104 as the substrate 100 is rotated. In some embodiments, the heads
404, 504 may be adapted to continuously or intermittently oscillate
between the various positions depicted and/or other positions. The
heads 404, 504 may be moved on the frame 502 by drivers 600 (FIG.
6) under the direction of a programmed or user operated controller.
Alternatively, the heads 404, 504 may be fixed and/or only adjusted
while the substrate is not being rotated. In yet other embodiments,
the substrate may be held fixed while the heads are oscillated (as
described above) as well as rotated circumferentially around the
substrate 100. Further, the polishing film 204 may be mounted on
the heads 404, 504 in a continuous loop and/or the polishing film
204 may be continuously (or intermittently) advanced to polish the
substrate edge 104. For example, the advancement of the film may be
used to create or enhance the polishing motion. Any combination of
the above described polishing motions and/or methods that are
practicable may be employed.
[0048] Turning to FIGS. 11 through 12, additional embodiments of an
edge polishing apparatus are depicted. FIG. 11 depicts an edge
polishing apparatus 1100 including three heads 404, FIG. 12 depicts
an edge polishing apparatus 1200 including two heads 504, and FIG.
13 depicts an edge polishing apparatus 1300 including four heads
1304. As suggested by the drawings, any number and type of heads
404, 504, 1304 may be used in any practicable combination. In
addition, in such multi-head embodiments, each head 404, 504, 1304
may used a differently configured or type of polishing film 204
(e.g., different grits, materials, tensions, pressures, etc.). Any
number of heads 404, 504, 1304 may be used concurrently,
individually, and/or in a sequence. Different heads 404, 504, 1304
may be used for different substrates 100 or different types of
substrates. For example, a first head 404 with a stiff biasing
device 406 supporting a pad 206 such as the concave pad 206B and a
coarse grit polishing film 204 may initially be used to remove a
relatively large amount of rough material from the substrate bevels
112, 114 (FIG. 1). The first head 404 may be appropriately
positioned to access the bevels 112, 114. After cleaning with the
first head 404 is completed, the first head 404 may be backed away
from the substrate 100, and a second head 504 with a fine grit
polishing film 204 (and without a pad) may be moved into position
to polish the bevels 112, 114 and the outer edge 110.
[0049] After cleaning one or more substrates 100, the portion of
the polishing film 204 employed for such cleaning may become worn.
Therefore, the take-up reel 210 (FIG. 4) may be driven to draw the
polishing film 204 by a fixed amount from the supply reel 210 (FIG.
4) toward the take-up reel 210. In this manner, an unused portion
of the polishing film 204 may be provided between the take-up reel
210 and supply reel 208. The unused portion of the polishing film
204 may be employed to subsequently clean one or more other
substrates 100 in a manner similar to that described above.
Consequently, the apparatus 1100, 1200 may replace a worn portion
of polishing film 204 with an unused portion with little or no
impact on substrate processing throughput. Likewise, if replaceable
cassettes 700A are employed, impact on throughput may be minimized
by quickly replacing the cassettes 700A when all the polishing film
204 in the cassette 700A is used.
[0050] Regarding the example embodiment of an edge polishing
apparatus 1300 of FIG. 13 specifically, a frame 1302 that supports
multiple heads 1304 is depicted in schematic form. The heads 1304
are each mounted to the frame 1302 and each include an actuator
1306 (e.g., pneumatic piston, servo driven slide, hydraulic ram,
etc.) adapted to press a pad 206 and a length of polishing film 204
against the edge 104 of a substrate 100 in response to a control
signal from a controller 1308 (e.g., a programmed computer, an
operator directed valve system, an embedded real time processor,
etc.). Note that the controller 1308 is coupled (e.g.,
electrically, mechanically, pneumatically, hydraulically, etc.) to
each of the actuators 1306.
[0051] In addition, a fluid supply 806 may be coupled to and under
the control of the controller 1308. The fluid supply 806 may be
controlled to independently deliver fluids (e.g., DI water,
cleaning chemistry, sonicated fluids, gas, air, etc.) to each of
the heads 1304 via one or more fluid channels 212. Under the
direction of the controller 1308, various fluids may be selectively
delivered to the pads 206, the polishing film 204, and/or the
substrate edge 104 via the fluid channels 212. The fluid may be for
use in polishing, lubricating, particle removal/rinsing, and/or
inflating a bladder 802 (FIG. 8C) within the pads 206. For example,
in some embodiments, the same fluid delivered through a permeable
pad 206 may be used for both polishing and inflating the pad 206
while a different fluid, delivered to the same head 1304 via a
second channel (not shown) is used for rinsing and lubricating.
[0052] The foregoing description discloses only exemplary
embodiments of the invention. Modifications of the above disclosed
apparatus and methods which fall within the scope of the invention
will be readily apparent to those of ordinary skill in the art. For
instance, although only examples of cleaning a round substrate are
disclosed, the present invention could be modified to clean
substrates having other shapes (e.g., a glass or polymer plate for
flat panel displays). Further, although processing of a single
substrate by the apparatus is shown above, in some embodiments, the
apparatus may process a plurality of substrates concurrently.
[0053] Accordingly, while the present invention has been disclosed
in connection with exemplary embodiments thereof, it should be
understood that other embodiments may fall within the spirit and
scope of the invention, as defined by the following claims.
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