U.S. patent application number 12/124145 was filed with the patent office on 2008-11-27 for methods and apparatus for using a bevel polishing head with an efficient tape routing arrangement.
This patent application is currently assigned to APPLIED MATERIALS, INC.. Invention is credited to Paul D. Butterfield, Shou-Sung Chang, Gary C. Ettinger, Sen-Hou Ko, Eashwer Kollata, Antoine P. Manens, Ricardo Martinez, Zhenhua Zhang.
Application Number | 20080293334 12/124145 |
Document ID | / |
Family ID | 40072853 |
Filed Date | 2008-11-27 |
United States Patent
Application |
20080293334 |
Kind Code |
A1 |
Kollata; Eashwer ; et
al. |
November 27, 2008 |
METHODS AND APPARATUS FOR USING A BEVEL POLISHING HEAD WITH AN
EFFICIENT TAPE ROUTING ARRANGEMENT
Abstract
Apparatus and methods are provided to polish an edge of a
substrate. The invention includes a polishing head, adapted to
contact an edge of a substrate, wherein the polishing head includes
one pair of front guide rollers and two pairs of back clamping
rollers. Numerous other aspects are provided.
Inventors: |
Kollata; Eashwer;
(Sunnyvale, CA) ; Chang; Shou-Sung; (Stanford,
CA) ; Zhang; Zhenhua; (San Jose, CA) ;
Butterfield; Paul D.; (San Jose, CA) ; Ko;
Sen-Hou; (Sunnyvale, CA) ; Manens; Antoine P.;
(Sunnyvale, CA) ; Ettinger; Gary C.; (Cupertino,
CA) ; Martinez; Ricardo; (Manteca, 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: |
40072853 |
Appl. No.: |
12/124145 |
Filed: |
May 21, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60939350 |
May 21, 2007 |
|
|
|
Current U.S.
Class: |
451/41 ; 451/177;
451/296 |
Current CPC
Class: |
B24B 21/004 20130101;
B24B 9/065 20130101 |
Class at
Publication: |
451/41 ; 451/296;
451/177 |
International
Class: |
B24B 1/00 20060101
B24B001/00 |
Claims
1. An apparatus for polishing an edge of a substrate, the apparatus
comprising: a polishing head, adapted to contact an edge of a
substrate, wherein the polishing head includes at least one front
roller adapted to guide a polishing tape and at least one pair of
back rollers adapted to maintain an alignment of the polishing
tape.
2. The apparatus of claim 1 wherein the front and back rollers are
adapted to rotate.
3. The apparatus of claim 1 wherein the polishing head includes a
pad.
4. The apparatus of claim 3 wherein the polishing head is adapted
to guide the polishing tape over the pad.
5. The apparatus of claim 4 wherein the pad is adapted to press the
polishing tape to contact the edge of the substrate.
6. The apparatus of claim 4 wherein the polishing tape is routed
between a first pair of back rollers, around a first front roller
and a second front roller, and then between a second pair of back
rollers.
7. The apparatus of claim 6 wherein a length of polishing tape
between the first and second front rollers is adapted to contact
the edge of the substrate.
8. The apparatus of claim 1 wherein the polishing head is adapted
to rock about the edge of the substrate.
9. The apparatus of claim 1 wherein the back rollers are
self-locking.
10. The apparatus of claim 6 wherein the polishing tape is
constrained from slipping off the pad by the back rollers.
11. A system for polishing an edge of a substrate, the system
comprising: a substrate support adapted to rotate a substrate; a
polishing head adapted to contact an edge of a substrate, wherein
the polishing head includes one pair of front rollers and two pairs
of back rollers; a controller adapted to operate the polishing of
the edge of the substrate.
12. The system of claim 11 wherein the polishing head includes a
polishing tape.
13. The system of claim 12 wherein the polishing head is adapted to
contact the edge of the substrate with the polishing tape.
14. The system of claim 12 wherein the polishing tape is routed
between the first pair of back rollers, around the first and second
front rollers, and then between the second pair of back
rollers.
15. The system of claim 14 wherein the length of polishing tape
between the first and second front rollers contacts the edge of the
substrate.
16. The system of claim 12 wherein the controller is adapted to
incrementally advance the polishing tape to the polishing head.
17. The system of claim 14 wherein the polishing tape is
constrained in the lateral direction by the back rollers.
18. The system of claim 11 wherein the front and back rollers are
adapted to rotate.
19. The system of claim 11 wherein the polishing head is adapted to
rock about the edge of the substrate.
20. A method for polishing an edge of a substrate comprising:
rotating a substrate; contacting an edge of the substrate with a
polishing head, wherein the polishing head includes one pair of
front rollers and two pairs of back rollers; routing a polishing
tape between the first pair of back rollers, around the first and
second front rollers, and then between the second pair of back
rollers, such that the length of polishing tape between the first
and second front rollers contacts and polishes the edge of the
substrate.
21. The method of claim 20 further comprising: advancing the
polishing tape in increments.
22. The method of claim 20 further comprising: advancing the
polishing tape continuously.
23. The method of claim 20 further comprising: constraining the
polishing tape in the lateral direction between each pair of back
rollers.
24. The method of claim 20 further comprising: pressing the
polishing tape against the edge of the substrate via a pad.
25. The method of claim 20 further comprising: rocking the
polishing head about the edge of the substrate.
Description
[0001] The present application claims priority from U.S.
Provisional Patent Application Ser. No. 60/939,350 filed May 21,
2007, entitled "METHODS AND APPARATUS FOR USING A BEVEL POLISHING
HEAD WITH AN EFFICIENT TAPE ROUTING ARRANGEMENT" (Attorney Docket
No. 11565/L) which is hereby incorporated herein by reference in
its entirety for all purposes.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] The present application is related to the following
commonly-assigned, co-pending U.S. patent applications, each of
which is hereby incorporated herein by reference in its entirety
for all purposes:
[0003] U.S. patent application Ser. No. 11/299,295, filed on Dec.
9, 2005, and entitled "METHODS AND APPARATUS FOR PROCESSING A
SUBSTRATE" (Attorney Docket No. 10121);
[0004] 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);
[0005] U.S. patent application Ser. No. 11/693,695, filed on Mar.
29, 2007, and entitled "METHODS AND APPARATUS FOR POLISHING AN EDGE
OF A SUBSTRAET" (Attorney Docket No. 10560);
[0006] U.S. Patent Application Ser. No. 60/939,351, filed May 21,
2007, entitled "METHODS AND APPARATUS FOR POLISHING A NOTCH OF A
SUBSTRATE USING AN INFLATABLE POLISHING WHEEL" (Attorney Docket No.
10674/L);
[0007] U.S. Patent Application Ser. No. 60/939,353, filed May 21,
2007, entitled "METHODS AND APPARATUS FOR FINDING A SUBSTRATE NOTCH
CENTER" (Attorney Docket No. 11244/L);
[0008] U.S. Patent Application Ser. No. 60/939,343, filed May 21,
2007, entitled "METHODS AND APPARATUS TO CONTROL SUBSTRATE BEVEL
AND EDGE POLISHING PROFILES OF EPITAXIAL FILMS" (Attorney Docket
No. 11417/L);
[0009] U.S. Patent Application Ser. No. 60/939,219, filed May 21,
2007, entitled "METHODS AND APPARATUS FOR POLISHING A NOTCH OF A
SUBSTRATE USING A SHAPED BACKING PAD" (Attorney Docket No.
11483/L);
[0010] U.S. Patent Application Ser. No. 60/939,342, filed May 21,
2007, entitled "METHODS AND APPARATUS FOR REMOVAL OF FILMS AND
FLAKES FROM THE EDGE OF BOTH SIDES OF A SUBSTRATE USING BACKING
PADS" (Attorney Docket No. 11564/L);
[0011] U.S. Patent Application Ser. No. 60/939,344, filed May 21,
2007, entitled "METHODS AND APPARATUS FOR USING A ROLLING BACKING
PAD FOR SUBSTRATE POLISHING" (Attorney Docket No. 11566/L);
[0012] U.S. Patent Application Ser. No. 60/939,333, filed May 21,
2007, entitled "METHODS AND APPARATUS FOR SUBSTRATE EDGE POLISHING
USING A POLISHING ARM" (Attorney Docket No. 11567/L);
[0013] U.S. Patent Application Ser. No. 60/939,212, filed May 21,
2007, entitled "METHODS AND APPARATUS FOR IDENTIFYING A SUBSTRATE
EDGE PROFILE AND ADJUSTING THE PROCESSING OF THE SUBSTRATE
ACCORDING TO THE IDENTIFIED EDGE PROFILE" (Attorney Docket No.
11695/L);
[0014] U.S. Patent Application Ser. No. 60/939,337, filed May 21,
2007, entitled "METHODS AND APPARATUS FOR HIGH PERFORMANCE
SUBSTRATE BEVEL AND EDGE POLISHING IN SEMICONDUCTOR MANUFACTURE"
(Attorney Docket No. 11809/L);
[0015] U.S. Patent Application Ser. No. 60/939,228, filed May 21,
2007, entitled "METHODS AND APPARATUS FOR POLISHING A NOTCH OF A
SUBSTRATE BY SUBSTRATE VIBRATION" (Attorney Docket No. 11952/L);
and
[0016] U.S. Patent Application Ser. No. 60/939,209, filed May 21,
2007, entitled "METHODS AND APPARATUS FOR CONTROLLING THE SIZE OF
AN EDGE EXCLUSION ZONE OF A SUBSTRATE" (Attorney Docket No.
11987/L).
FIELD OF THE INVENTION
[0017] The present invention relates generally to substrate
processing, and more particularly to methods and apparatus for
cleaning an edge of a substrate.
BACKGROUND OF THE INVENTION
[0018] Substrates are used in semi-conductor device manufacturing.
During processing, the edge of the substrate may become dirty,
which may negatively affect the semi-conductor devices.
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 tape or film may not sufficiently contact
both bevels of the edge during cleaning. Additionally, the abrasive
tape may run-off during the polishing process, especially when the
tape is minimally tensioned. The inability to sufficiently clean
the substrate may affect semiconductor device manufacturing
throughput. Accordingly improved methods and apparatus for cleaning
an edge of a substrate are desired.
SUMMARY OF THE INVENTION
[0019] In aspects of the invention, an apparatus is provided for
polishing an edge of a substrate. The apparatus comprises a
polishing head, adapted to contact an edge of a substrate, wherein
the polishing head includes one pair of front guide rollers and two
pairs of back clamping rollers.
[0020] In other aspects of the invention, a system is provided for
polishing an edge of a substrate. The system comprises a substrate
support adapted to rotate a substrate; a polishing head adapted to
contact an edge of a substrate, wherein the polishing head includes
one pair of front rollers and two pairs of back rollers; a
controller adapted to operate the polishing of the edge of the
substrate.
[0021] In yet other aspects of the invention, a method is provided
for polishing an edge of a substrate. The method comprises rotating
a substrate; contacting an edge of the substrate with a polishing
head, wherein the polishing head includes one pair of front rollers
and two pairs of back rollers; routing a polishing tape between the
first pair of back rollers, around the first and second front
rollers, and then between the second pair of back rollers, such
that the length of polishing tape between the first and second
front rollers contacts and polishes the edge of the substrate.
[0022] 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
[0023] FIG. 1 is a schematic illustration of a cross-section of a
portion of a substrate.
[0024] FIG. 2 is a perspective illustration depicting an example
embodiment of an edge cleaning apparatus according to the present
invention.
[0025] FIG. 3 is a plan view depicting an example embodiment of an
edge cleaning system according to the present invention.
[0026] FIG. 4 is a perspective view of a polishing head according
to the present invention.
[0027] FIG. 5 is a schematic illustration of the polishing head of
the bevel polishing module according to the present invention.
[0028] FIG. 6 is a flowchart depicting the application of the
polishing tape to an edge of a substrate according to the present
invention.
DETAILED DESCRIPTION
[0029] The present invention provides improved methods, systems and
apparatus for cleaning and/or polishing the edge of a substrate.
The edge of a substrate may be polished by application of an
abrasive polishing tape contacting the substrate edge (via a
backing pad, in some embodiments) as the substrate is rotated or
otherwise moved (e.g., oscillated). However, the polishing tape may
run-off the polishing head, even when the apparatus is being
operated with minimal tape tension values. According to the present
invention, in some embodiments a polishing head is provided that
may include a top plate, located in a plane opposite and parallel
to a bottom plate. A pair of front guide rollers may be positioned
between the top plate and the bottom plate. A first and second pair
of back rollers may also be positioned between the top and bottom
plates, and opposite each front roller. The back rollers may
function to clamp the polishing tape that is routed between the
rollers so that the polishing tape maintains alignment on the
rollers without requiring tension along the length of the polishing
tape. The front and back rollers may be arranged to route the
polishing tape around or over the backing pad. In some embodiments,
the space between the two back rollers in each pair of back rollers
may be limited such that the polishing tape may be constrained in
the lateral direction by the walls of the rollers. This may help to
ensure that the tape does not run-off the polishing head, even when
the apparatus is being operated with minimal tape tension
values.
[0030] 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.)
[0031] 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.
[0032] As shown in FIG. 2, an example of an edge polishing
apparatus 200 is depicted. The apparatus 200 may include a base or
frame 202 that includes a head 204 which supports a length of
polishing tape 201. The polishing tape 201 may be tensioned between
front and back rollers 210, 212, and further supported by a backing
pad 203. The backing pad 203 may be mounted to the head 204 via an
actuator (e.g., a pneumatic slide, hydraulic ram, servo motor
driven pusher, etc.) (not shown). The edge polishing apparatus 200
of FIG. 2 also may include a vacuum chuck 205 coupled to a driver
208 (e.g., motor, gear, belt, chain, etc.). Unlike some embodiments
which may include one or more drive rollers (not shown) and guide
rollers (not shown) that are adapted to rotate the substrate 100
such that the substrate edge 104 is rotated against the polishing
tape 201, an advantage of using the vacuum chuck 205 may be that
the vacuum chuck 205 does not need to contact the substrate edge
104 being polished. Thus, the potential of particles accumulating
on drive rollers and being re-deposited on the substrate edge 104
is eliminated. The need to clean rollers also is eliminated.
Further, the possibility of rollers damaging or scratching the
substrate edge 104 may also eliminated. By holding the substrate
100 in the vacuum chuck 205, high speed rotation without
significant vibration may be achieved.
[0033] The polishing tape 201 may be supplied to the head 204 by a
set of spools including a supply spool 209 and a take-up spool 211.
The spools 209, 211 may be driven by one or more drivers 213, 215
(e.g., servo motors) which may provide an indexing capability to
allow a specific amount of unused polishing tape 201 to be advanced
or continuously fed to the substrate edge 104, and/or a tensioning
capability to allow the polishing tape 201 to be stretched taught
and to apply pressure to the substrate edge 104.
[0034] The front and back rollers 210, 212 may be adapted to apply
a variable amount of tension to the polishing tape 201, and thereby
the substrate edge 104, so as to attain precise control over an
edge polishing process which may be used to compensate for
different edge geometries and changes in the substrate 100 as
material is removed from the substrate edge 104.
[0035] The substrate 100 may contact the abrasive tape 201 for
about 15 to about 150 seconds depending on the type of tape used,
the grit of the tape, the rate of rotation, the amount of polishing
required, etc. More or less time may be used. The contact between
the backing pad 203, and hence polishing tape 201, and the
substrate edge 104 combined with the particular rotation speed of
the substrate 100, may provide relative movement between the
polishing tape 201 and the substrate edge 104, resulting in the
substrate edge 104 being polished. 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 polishing tape, a controlled amount of pressure may
be applied to polish the substrate edge 104. Thus, the present
invention may provide 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
substrate edge 104.
[0036] The substrate 100 may be rotated in a horizontal plane. The
edge 104 of the substrate 100 may be aligned with, or normal to,
the polishing tape 201, pad 203 and/or polishing head 204. 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.
[0037] FIG. 3 is a plan view depicting another example embodiment
of an edge cleaning system 300 according to the present invention.
FIG. 3 depicts an edge polishing system 300 including three heads
304, each attached to a polishing apparatus 303. The polishing
apparatuses 303 shown herein, include features similar to the
polishing apparatuses 200 described above with respect to FIG. 2.
As suggested by FIG. 2 and FIG. 3, any number and type of heads 304
may be used in any practicable combination. Substrate [edge/notch]
polishing may be performed using one or more polishing apparatuses
303. In one or more embodiments, a plurality of polishing
apparatuses 303 may be employed, in which each polishing apparatus
may have similar or different characteristics and/or mechanisms. In
the latter case, particular polishing apparatuses 303 may be
employed for specific operations. For example, one or more of a
plurality of polishing apparatuses 303 may be adapted to perform
relatively rough/coarse polishing and/or adjustments while another
one or more of the plurality of polishing apparatus may be adapted
to perform relatively fine polishing and/or adjustments. Polishing
apparatuses 303 may be used in sequence so that, for example, a
rough polishing procedure may be performed initially and a fine
polishing procedure may be employed subsequently to make
adjustments to a relatively rough polish as needed or according to
a polishing recipe. The plurality of polishing apparatuses 303 may
be located in a single chamber or module, as shown herein, or
alternatively, one or more polishing apparatuses 303 may be located
in separate chambers or modules. Where multiple chambers are
employed, a robot or another type of transfer mechanism may be
employed to move substrates between the chambers so that polishing
apparatuses in the separate chambers may be used in series or
otherwise.
[0038] In addition, in such multi-head embodiments, each head 304
may use a differently configured or type of polishing tape 201
(e.g., different grits, materials, tensions, pressures, etc.). Any
number of heads 304 may be used concurrently, individually, and/or
in any sequence. The heads 304 may be disposed in different
positions and in different orientations (e.g., aligned with the
substrate edge 104, normal to the substrate edge 104, angled
relative to the substrate edge 104, etc.) to allow the tape 201 to
polish different portions of the edge 104 of the substrate 100.
[0039] In some embodiments, one or more of the heads 304 may be
adapted to be oscillated or moved (e.g., angularly translated about
a tangential axis of the substrate 100 and/or circumferentially
relative to the substrate 100) around or along the substrate edge
104 by the frame 202 so as to polish different portions of the
substrate edge 104. Different heads 304 may be used for different
substrates 100 or different types of substrates.
[0040] As further described below, the system 300 may further
include a controller 306, (e.g., a programmed computer, a
programmed processor, a microcontroller, a gate array, a logic
circuit, an embedded real time processor, etc.), which may control
the driver(s) used to rotate the substrate 100 and/or the
actuator(s) used to push the polishing pad(s) 203 against the
substrate edge 104. Note that the controller 306 may be coupled
(e.g., electrically, mechanically, pneumatically, hydraulically,
etc.) to each of a plurality of actuators. Likewise, the controller
306 may be adapted to receive feedback signals from one or more
drivers and/or actuators, that indicate the amount of energy being
exerted to rotate the substrate 100 (e.g., rotate a vacuum chuck
holding the substrate 100) and/or actuate the actuator(s) to push
the polishing pad(s) 203 against the substrate 100. These feedback
signals may be employed to determine when a particular layer of
film has been removed and/or whether a sufficient amount of
polishing has occurred.
[0041] Turning to FIG. 4, an exemplary polishing head 400 for use
with the polishing tape 201, shown in FIG. 5, to clean the edge 104
of the substrate 100 is provided. The surface of the polishing tape
201 in contact with the substrate edge 104 may include an abrasive
material to expedite the polishing. In one or more embodiments, the
polishing tape 206 may be made from one or more different materials
including, for example, aluminum oxide, silicon oxide, silicon
carbide, etc. Other materials may also be used. In some
embodiments, the abrasive particles forming the abrasive material
may range from about 0.5 microns up to about 3 microns in size,
although other sizes may be used. Different widths of tape ranging
from about 0.2 inches to about 1.5 inches may be used (although
other widths may be used). In one or more embodiments, the
polishing tape 201 may be about 0.002 inches to about 0.02 inches
thick, and be able to withstand about 1 to about 5 lbs. of tension
in embodiments that use a pad, and from about 3 to about 8 lbs. of
tension in embodiments without a pad. Other tapes having different
thicknesses and strengths may be used. The supply and take-up
spools 209, 211 (FIG. 2) may be approximately 1 inch to
approximately 4 inches in diameter, hold up to approximately 5000
inches of polishing tape 201, and may be constructed from any
practicable materials such as polyurethane, polyvinyl difloride
(PVDF), etc. Other materials may be used. The supply and take-up
spools 209, 210 may also have other dimensions and hold other
amounts of polishing tape 201.
[0042] The polishing head 400 may include a top plate 402, located
in a plane opposite and parallel to a bottom plate 404. A pair of
front rollers 406a,406b may be positioned between the top plate 402
and the bottom plate 404, such that the front rollers 406a,406b are
able to rotate in a plane perpendicular, or alternatively,
substantially perpendicular to the top and bottom plates 402,404.
In other words, the axis of rotation may be perpendicular (or
substantially so) to the horizontal plane of the top and bottom
plates 402, 404, and therefore the plane of rotation may be
parallel to the top and bottom plates 402, 404. A first and second
pair of back rollers 408a and 408b may be positioned between the
top and bottom plates 402, 404 and opposite each front roller 406a
and 406 b, respectively, and may rotate in the same rotational
orientation as the front rollers 406.
[0043] The rollers may be designed for maximum diameter to reduce
friction. The rollers may be made of a plastic bearing material
including but not limited to PTFE and PEEK.
[0044] Turning to FIG. 5, an top view schematic illustration of the
polishing head 400 (with top plate 402 removed for clarity), shown
above in FIG. 4, of the bevel polishing module is depicted. The
front and back rollers 406a,406b, & 408a,408b may be arranged
to route the polishing tape 201 (not shown in FIG. 4, but see FIG.
5) around the backing pad 203. The arrangement of rollers
406a,406b,408a,408b may accurately align the tape 201 around the
backing pad 203. In some embodiments, the back rollers 408a,408b
may be self-locking. In some embodiments, the space between the two
back rollers 408a in the first pair and 408b in the second pair of
back rollers may be very limited. Thus, the polishing tape 201
routed through each of the first and second pairs of back rollers
408a and 408b may be constrained in the lateral direction by the
walls of the rollers 408a,408b. This may help to ensure that the
tape 201 does not run-off the polishing head 400, even when the
apparatus is being operated with minimal tape 201 tension values.
Other back roller 408a,408b orientations may be used.
[0045] In some embodiments, the back rollers 408a,408b may be
disposed so close together that the back rollers 408a,408b
effectively clamp the polishing tape 201 and prevent the polishing
tape 201 from moving along the longitudinal dimension of the back
rollers 408a,408b and consequently prevent the polishing tape 201
from moving along the longitudinal dimension of the front rollers
406a,406b as well as prevent the polishing tape 201 from slipping
off the backing pad 203. In other words, without having to rely on
high tension applied to the polishing tape 201 along the length of
the polishing tape 201 (i.e., in the longitudinal dimension of the
polishing tape 201) to keep the polishing tape 201 aligned on the
front rollers 406a,406b and the backing pad 203, the present
invention facilitates maintaining the alignment of the polishing
tape 201 on the front rollers 406a,406b and the backing pad 203 by
using two pairs of back rollers 408a,408b which each clamp the
polishing tape 201 on either side of the front rollers 406a,406b
which allows the polishing tape 201 to move through the polishing
head 400 but not move laterally off the rollers towards the top
plate 402 or bottom plate 404.
[0046] In some embodiments, the front rollers 406a,b may be placed
close to the backing pad 203 (e.g., disposed so as to guide the
polishing tape 201 out to a plane that is almost co-planar with the
backing pad 203) to reduce the amount of displacement of the
polishing tape 201 by the backing pad 203 needed to make the
polishing tape 201 contact the edge 104 of the substrate 100. Other
front roller orientations may be used. The front and back roller
406a,406b,408a,408b arrangement may reduce the effect of the
polishing tape 201 tension on the backing pad 203. In some
embodiments (e.g., embodiments that use a roller backing pad 203),
the front rollers 406a,406b may be removed, and the polishing tape
201 may be routed just over the backing pad 203.
[0047] In some embodiments, the spool of polishing tape 201 mounted
to the head 400, may be driven by one or more drivers 213, 215,
e.g., servo motors (FIG. 2). The drivers 213, 215 may provide both
an indexing capability to allow a specific amount of unused
polishing tape 201 to be advanced or continuously fed to the
substrate edge 104, and a tensioning capability to allow the
polishing tape 201 to be stretched taught and to apply pressure to
the substrate edge 104. Alternatively or additionally, the abrasive
side of the polishing tape 201 may be pressed against the substrate
edge 104 using the backing pad 203, mounted to the head 400 and
pushed by an actuator and/or by inflation of an inflatable pad. In
embodiments described herein, the polishing head 400 may rock
around the edge 104 of the substrate 100 to polish the entire
substrate edge 104. The angle of rocking may include, for example,
plus or minus 90 degrees. Other suitable rocking angles may be
used. In operation, the rocking motion may be achieved by angularly
translating the head 400 and consequently, a portion of polishing
tape 201 in contact with, and contoured to, the edge 104 of the
substrate 100 around an axis that is tangential to the outer edge
110 of the substrate 100 as the substrate 100 is rotated. For
example, the polishing head 400 may start polishing at the upper
bevel 112, adjust to polish the outer edge 110 and then adjust
again to polish the lower bevel 114. While the polishing head 400
rocks about the edge 104, the entire substrate 100 may be rotated
such that the entire circumferential edge 104 of the substrate 100
may be polished. The substrate 100 may be rotated by, a vacuum
chuck or driver rollers, as described above. Other suitable
substrate rotation devices may be used. In some embodiments, the
head 400 may be adapted to continuously or intermittently oscillate
between various positions. As described above, the head 400 may be
moved by drivers (not shown) under the direction of a programmed or
user operated controller 306. Alternatively, the head 400 may be
fixed and/or only adjusted while the substrate 100 is not being
rotated. In yet other embodiments, the substrate 100 may be held
fixed while the head 400 is oscillated (as described above) as well
as rotated circumferentially around the substrate 100. The front
and back roller 406a,b, 408a,b arrangement may ensure that the
contact between the tape 201 and the substrate 100 is consistent at
any angle during the rotation of the head 400.
[0048] Further, the polishing tape 201 may be mounted on the head
400 in a continuous loop and/or the polishing tape 201 may be
continuously (or intermittently) advanced to polish and/or increase
the polishing effect on the substrate edge 104. For example, the
advancement of the tape 201 may be used to create and/or enhance
the polishing motion. In some embodiments the tape 201 may be
oscillated back and forth to polish and/or enhance the polishing
effect on a stationary or rotating substrate 100. In some
embodiments, the tape 201 may be held stationary during polishing.
Further, the tape 201 tension and/or force may be varied based on
various factors including, for example, the angle and/or position
of the polishing tape 201, the polishing time, the materials used
in the substrate, the layer being polished, the amount of material
removed, the speed at which the substrate is being rotated, the
amount of current being drawn by the driver rotating the substrate,
etc. Any combination of the above described polishing motions
and/or methods that are practicable may be employed. These methods
provide additional control over the edge polish process which can
be used to compensate for geometry and changes in the material
being removed as the tape 201 is rotated/moved about, or relative
to, the substrate edge 104.
[0049] FIG. 6 is a flowchart depicting an exemplary method 600 for
loading polishing tape 201 for use in a bevel polishing system 300.
In step S602, an appropriate polishing tape 201 is selected. The
type of polishing tape selected may vary depending on, for example,
a particular abrasiveness, liquid chemicals being used, tape
durability, polishing process etc. In step S604, the spool of
polishing tape 201 is inserted in the bevel polishing system 300.
In some embodiments, the system 300 may include a supply spool 209
of tape for supplying polishing tape and a take-up spool 211 for
receiving the used polishing tape. The supply spool 209 of
polishing tape 201 may be inserted in the supply spool location of
the system 300. Then the polishing tape 201 may be routed between
the first pair of back rollers 408a in step S606. Routing the
polishing tape 201 between the two rollers forming each pair of
back rollers 408a and 408b, may prevent, or lessen, lateral
movement of the polishing tape 201, which may disrupt the polishing
process. The polishing tape 201 may then be routed around the
outside of the first front roller 406a in step S608. Then the
polishing tape 201 may be routed over the backing pad 203, and
around the outside of the second front roller 406b in steps S610
and S612, respectively. The portion of the polishing tape 201 over
the backing pad 203 may be pressed by the backing pad 203 onto the
edge 104 of the substrate 100. The rotation of the substrate 100,
as well as the movement of the polishing tape 201 against the edge
104 of the substrate 100, is how the substrate edge 104 may be
polished. In step S614, the polishing tape 201 may then be routed
between the second pair of back rollers 408b. The loose end of the
polishing tape 201 is then affixed to the take-up spool 211 in step
S616. After cleaning one or more substrates 100, the portion of the
polishing tape 201 employed for such cleaning may become worn.
Therefore, the take-up spool 211 may be driven to draw the
polishing tape 201 by a fixed amount from the supply spool 209
toward the take-up spool 211. In this manner, an unused portion of
the polishing tape 201 may be provided between the take-up spool
211 and the supply spool 209. The unused portion of the polishing
tape 201 may be employed to subsequently clean one or more other
substrates 100 in a manner similar to that described above.
Consequently, a worn portion of polishing tape 201 may be replaced
with an unused portion with little or no impact on substrate
processing throughput. In some embodiments, the polishing tape 201
may be considered to be "worn," for example, after being applied to
a predetermined number of substrates. The type of polishing being
performed may impact the predetermined number of substrates, for
example. In alternative embodiments, the polishing tape 201 may be
considered "worn" after the size or number, for example, of
abrasive particles/materials has decreased by a particular amount.
This determination may be made by the controller 306 after
receiving feedback from sensors, for example.
[0050] It should be understood that the inventive edge polishing
apparatus described herein may be employed in apparatuses other
than those adapted for bevel and edge polishing and/or removal of
films on substrates. Further, as will be apparent to those of
ordinary skill in the art, the apparatus describe herein may be
employed to polish and/or remove films on an edge of a substrate
supported in any orientation (e.g., horizontal, vertical, diagonal,
etc).
[0051] Further, it should be understood that 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.
[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.
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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