U.S. patent application number 12/124137 was filed with the patent office on 2008-11-27 for methods and apparatus for polishing a notch of a substrate using a polishing pad.
This patent application is currently assigned to APPLIED MATERIALS, INC.. Invention is credited to Paul D. Butterfield, Shou-Sung Chang, Gary C. Ettinger, Eashwer Kollata, Antoine P. Manens, Zhenhua Zhang.
Application Number | 20080293344 12/124137 |
Document ID | / |
Family ID | 40072862 |
Filed Date | 2008-11-27 |
United States Patent
Application |
20080293344 |
Kind Code |
A1 |
Ettinger; Gary C. ; et
al. |
November 27, 2008 |
METHODS AND APPARATUS FOR POLISHING A NOTCH OF A SUBSTRATE USING A
POLISHING PAD
Abstract
Methods and apparatus are provided for polishing a notch of a
substrate using a polishing tape. In some embodiments, a polishing
head may be provided that is adapted to apply the polishing tape
against the notch of the substrate, including: a polishing pad
having a cavity adapted to be filled with a pressure-controlled
medium; and a tip region having a shape that corresponds to a shape
of the notch, wherein the polishing pad is adapted to contact the
polishing tape and press the polishing tape against the notch.
Numerous other aspects are provided.
Inventors: |
Ettinger; Gary C.;
(Cupertino, CA) ; Butterfield; Paul D.; (San Jose,
CA) ; Manens; Antoine P.; (Sunnyvale, CA) ;
Zhang; Zhenhua; (San Jose, CA) ; Kollata;
Eashwer; (Sunnyvale, CA) ; Chang; Shou-Sung;
(Stanford, 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: |
40072862 |
Appl. No.: |
12/124137 |
Filed: |
May 20, 2008 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60939351 |
May 21, 2007 |
|
|
|
60939219 |
May 21, 2007 |
|
|
|
61046799 |
Apr 21, 2008 |
|
|
|
Current U.S.
Class: |
451/527 ;
451/442 |
Current CPC
Class: |
B24B 9/065 20130101;
B24B 21/002 20130101; B24B 1/002 20130101 |
Class at
Publication: |
451/527 ;
451/442 |
International
Class: |
B24D 11/00 20060101
B24D011/00; B24B 55/00 20060101 B24B055/00 |
Claims
1. An apparatus for polishing a notch of a substrate using a
polishing tape comprising: a polishing head adapted to apply the
polishing tape against the notch of the substrate, including: a
polishing pad having: a cavity adapted to be filled with a
pressure-controlled medium; and a tip region having a shape that
corresponds to a shape of the notch, wherein the polishing pad is
adapted to contact the polishing tape and press the polishing tape
against the notch.
2. The apparatus of claim 1 wherein the pressure-controlled medium
is a pressurizable gas.
3. The apparatus of claim 1 wherein the polishing pad is
wheel-shaped.
4. The apparatus of claim 3 wherein the polishing pad is adapted to
rotate with a circumferential speed substantially equal to a
polishing tape advancement speed.
5. The apparatus of claim 1 wherein the polishing pad is
substantially planar-shaped.
6. The apparatus of claim 1 wherein the polishing pad includes an
outer skin layer.
7. An apparatus for polishing a notch of a substrate using a
polishing tape comprising: a polishing head adapted to apply the
polishing tape against the notch of the substrate, comprising: a
polishing pad having a tip region having a shape that corresponds
to a shape of the notch, the polishing pad adapted to contact the
polishing tape and press the polishing tape against the notch; and
one or more guides adapted to prevent the polishing tape from
moving out from between the polishing pad and the notch.
8. The apparatus of claim 7 wherein the polishing pad is
wheel-shaped.
9. The apparatus of claim 8 wherein the polishing pad is adapted to
rotate.
10. The apparatus of claim 9 wherein the polishing pad is adapted
to rotate with a circumferential speed substantially equal to a
polishing tape advancement speed.
11. The apparatus of claim 7 wherein the polishing pad is
substantially planar-shaped.
12. The apparatus of claim 7 wherein the polishing pad includes an
outer skin layer.
13. The apparatus of claim 12 wherein the outer skin layer is
adapted to cover a ridge region.
14. The apparatus of claim 12 wherein the polishing tape is adapted
to travel over the ridge region during application of the polishing
tape to the notch.
15. The apparatus of claim 7 wherein the one or more guides are
coupled to one or more support blocks.
16. The apparatus of claim 7 wherein the one or more guides are
integrally formed in one or more support blocks.
17. An apparatus for polishing a notch of a substrate using a
polishing tape comprising: a polishing head adapted to apply the
polishing tape against the notch of the substrate, including: a
polishing pad including one or more slots for guiding the polishing
tape; and a notch polishing pad embedded in the polishing pad and
adapted to contact the polishing tape and press the polishing tape
against the notch.
18. The apparatus of claim 17 wherein the polishing pad is
wheel-shaped.
19. The apparatus of claim 18 wherein the polishing pad is adapted
to rotate.
20. The apparatus of claim 17 wherein the polishing pad is
substantially planar-shaped.
21. The apparatus of claim 17 wherein the notch polishing pad
includes a protruding portion having a shape that corresponds to a
shape of the notch.
22. The apparatus of claim 21 wherein the protruding portion
includes a bore.
23. The apparatus of claim 21 wherein the notch polishing pad
includes at least one plateau region.
24. The apparatus of claim 23 wherein the at least one plateau
region is adapted to conform the polishing tape to at least one
corner of the notch.
25. The apparatus claim 21 wherein the protruding portion has a
height and the notch has a depth and wherein the height of the
protruding portion is greater than the depth of the notch.
26. The apparatus of claim 17 wherein the polishing pad has a
hardness of less than about 70 Shore A durometers.
Description
[0001] The present application claims priority from the following
U.S. patent applications, each of which is hereby incorporated by
reference herein in its entirety:
[0002] U.S. Provisional 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); U.S. Provisional 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); and
[0003] U.S. Provisional Patent Application Ser. No. 61/046,799,
filed Apr. 21, 2008, entitled "APPARATUS AND METHODS FOR POLISHING
A NOTCH OF A SUBSTRATE USING A POLISHING WHEEL" (Attorney Docket
No. 11540/L).
CROSS-REFERENCE TO RELATED APPLICATIONS
[0004] 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:
[0005] 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/PPC/CMP/CKIM);
[0006] 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/PPC/CMP/CKIM);
[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. 60/939,342, 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);
[0010] U.S. 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);
[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 a notch in an edge of a substrate.
BACKGROUND OF THE INVENTION
[0018] Conventional systems, which contact a notch in the edge of a
substrate with an abrasive film or tape to clean the notch, may not
be able to contact all parts of the notch with the abrasive tape.
As a result, these conventional systems may not be able to clean or
polish all parts of the notch. Accordingly, effective methods and
apparatus for cleaning or polishing all parts of notches in the
edges of substrates are desired.
SUMMARY OF THE INVENTION
[0019] In aspects of the invention, an apparatus is provided for
polishing a notch of a substrate using a polishing tape. The
apparatus comprises a polishing head adapted to apply the polishing
tape against the notch of the substrate, including: a polishing pad
having a cavity adapted to be filled with a pressure-controlled
medium; and a tip region having a shape that corresponds to a shape
of the notch, wherein the polishing pad is adapted to contact the
polishing tape and press the polishing tape against the notch.
[0020] In other aspects of the invention, an apparatus is provided
for polishing a notch of a substrate using a polishing tape. The
apparatus comprises a polishing head adapted to apply the polishing
tape against the notch of the substrate, comprising: a polishing
pad having a tip region having a shape that corresponds to a shape
of the notch, the polishing pad adapted to contact the polishing
tape and press the polishing tape against the notch; and one or
more guides which are adapted to prevent the polishing tape from
moving out from between the polishing pad and the notch.
[0021] In yet other aspects of the invention, an apparatus for
polishing a notch of a substrate using a polishing tape is
provided. The apparatus comprises a polishing head adapted to apply
the polishing tape against the notch of the substrate, including: a
polishing pad including one or more slots for guiding the polishing
tape; and a notch polishing pad embedded in the polishing pad and
adapted to contact the polishing tape and press the polishing tape
against the notch.
[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 DRAWINGS
[0023] FIG. 1 is a schematic illustration of a cross-section of a
portion of a substrate.
[0024] FIG. 2 is a schematic plan view of an embodiment of a system
for polishing parts of a substrate, including major surfaces, edge,
bevel, and notch in accordance with the present invention.
[0025] FIG. 3 is a schematic perspective view of a first embodiment
of a polishing apparatus for polishing a substrate notch in
accordance with the present invention.
[0026] FIG. 4 is a schematic perspective view of a second
embodiment of a polishing apparatus for polishing a substrate notch
in accordance with the present invention.
[0027] FIG. 5 is a schematic illustration of part of a substrate,
including a substrate notch.
[0028] FIG. 6 is a schematic perspective view of a portion of an
embodiment of the notch polishing apparatus of FIG. 3.
[0029] FIG. 7 is a schematic cross-sectional view of an embodiment
of a polishing wheel in accordance with the present invention.
[0030] FIG. 8 is an enlarged schematic cross-sectional view of a
portion of the polishing wheel of FIG. 7, in the region of FIG. 7
enclosed by a dashed circle and labeled FIG. 8.
[0031] FIGS. 9A and 9B are schematic perspective views of a portion
of an embodiment of the notch polishing apparatus of FIG. 3.
[0032] FIG. 10A is a schematic plan view of an alternate embodiment
of a notch polishing apparatus provided in accordance with the
present invention.
[0033] FIG. 10B is a schematic plan view of another embodiment of
the notch polishing apparatus of FIG. 10A.
[0034] FIG. 10C is a schematic side view of the notch polishing
apparatus of FIG. 10A.
[0035] FIG. 11 is a schematic perspective view of an embodiment of
a supporting polishing pad for polishing a substrate notch provided
in accordance with the present invention.
[0036] FIG. 12 is a schematic perspective view of part of the
embodiment of a polishing apparatus for polishing a substrate
notch, similar to the polishing apparatus of FIG. 3, which employs
the supporting polishing pad of FIG. 11.
[0037] FIG. 13 is a schematic cross-sectional view of the
supporting polishing pad of FIG. 11.
[0038] FIG. 14 is a schematic cross-sectional view of an
alternative embodiment of a supporting polishing pad, whose notch
polishing pad contains a bore in accordance with the present
invention.
[0039] FIG. 15 is a schematic cross-sectional view of a further
embodiment of a supporting polishing pad in accordance with the
present invention.
[0040] FIG. 16 is a schematic cross-sectional view of a further
embodiment of a supporting polishing pad, whose notch polishing pad
contains a bore in accordance with the present invention.
[0041] FIG. 17 is a flow chart of a method for polishing a
substrate notch provided in accordance with the present
invention.
[0042] FIG. 18 is a flow chart of an alternative method for
polishing a substrate notch provided in accordance with the present
invention.
DETAILED DESCRIPTION
[0043] Substrates used in semiconductor processing often have films
and/or surface defects which typically should be removed prior to
subsequent processing steps. In some cases, these films and defects
may occur on the edge of a substrate, including notches formed
thereon.
[0044] The present invention provides apparatus and methods that
effectively adapt to various shapes of notches found in different
substrates, ensure good contact of a polishing tape or film with
all sections of a substrate notch region, and remove thin films and
surface defects at a substrate notch.
[0045] In one or more embodiments, a polishing wheel or pad may be
provided. The polishing wheel or pad may be adapted to press a
moving polishing tape against the substrate notch. The polishing
wheel or pad may include a tip region that substantially conforms
to the shape of the substrate notch.
[0046] In some embodiments, the polishing wheel or pad may be
hollow and filled with a resilient material or be made entirely
from a resilient material. In some embodiments the polishing pad
may be made from PTFE, PEEK, Delrin, ceramics, or stainless steel,
for example. Other suitable materials may be used. In some
embodiments, the polishing pad may have a hardness of about 60-70
Shore A durometers, for example. Materials having more or less
hardness may be used. In alternative embodiments, the polishing
wheel or pad may be hollow and filled with a pressure-controlled
fluid to effectively press the polishing tape against all sections
of the substrate notch.
[0047] Turning 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'. A notch 116 may be located in the edge 104 of
the substrate 100, and used to align/position the substrate 100
during various processing steps (e.g., lithography, deposition,
etching, cleaning, etc.). The present invention is adapted to
polish the notch 116.
[0048] FIG. 2 is a schematic plan view of an exemplary embodiment
of a system 200 for polishing parts of the substrate 100, including
the major surfaces 102, 102', the edge 104, and/or the notch 116.
The system 200 of FIG. 2 includes three polishing apparatuses 202,
each including a polishing head 204. However, any number and type
of apparatus 202/heads 204 may be used in any practicable
combination. In addition, in such multi-head embodiments, each head
204 may use a differently configured or type of a polishing tape
(e.g., different grits, materials, tensions, pressures, etc.) to
contact and polish the substrate notch 116. Any number of heads 204
may be used concurrently, individually, and/or in any sequence. The
heads 204 may be disposed in different positions and in different
orientations (e.g., aligned with the substrate notch 116, normal to
the substrate notch 116, angled relative to the substrate notch
116, etc.) to allow polishing tape, pushed by a pad in some
embodiments (FIG. 3), to polish different portions of the notch 116
of the substrate 100.
[0049] In some embodiments, one or more of the heads 204 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 notch
116 so as to polish different portions of the substrate notch 116.
In some embodiments, one or more of the heads 204 may be adapted to
continuously or intermittently oscillate between the various
positions. Alternatively, one or more of the heads 204 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
one or more of the heads 204 oscillate (as described above) as well
as rotate circumferentially around the substrate 100. This movement
may be under the direction of a programmed or user operated
controller 205, described below. Different heads 204 may be used
for different substrates 100 or different types of substrates
100.
[0050] As described above, the system 200 may further include the
controller 205, (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 a polishing pad(s) (FIG. 3) against the substrate
notch 116. Note that the controller 205 may be coupled (e.g.,
electrically, mechanically, pneumatically, hydraulically, etc.) to
each of a plurality of actuators. Likewise, the controller 205 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) 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.
[0051] As mentioned above, substrate polishing may be performed
using one or more polishing apparatuses 202. In one or more
embodiments, a plurality of polishing apparatuses 202 may be
employed, in which each polishing apparatus 202 may have similar or
different characteristics and/or mechanisms. In the latter case,
particular polishing apparatuses 202 may be employed for specific
operations. For example, one or more polishing apparatuses 202 may
be adapted to perform relatively rough polishing and/or adjustments
while another one or more polishing apparatus 202 may be adapted to
perform relatively fine polishing and/or adjustments. Polishing
apparatuses 202 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 as needed or
according to a polishing recipe. The plurality of polishing
apparatuses 202 may be located in a single chamber or module, as
shown herein, or alternatively, one or more polishing apparatuses
202 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 202 in the separate chambers may be
used in series or otherwise.
[0052] FIG. 3 is a schematic perspective view of a second exemplary
embodiment of a polishing apparatus 300 for polishing a substrate
notch 116. The polishing apparatus 300 may include a substrate
driver 302 (e.g., a servomotor, gear, belt, chain, etc.), which may
be mounted on a pedestal 304. A support 306 (e.g., a vacuum chuck)
may be coupled (e.g., rigidly) to a shaft (not shown) of the
substrate driver 302. The support 306 may support the substrate
100, for example. The substrate driver 302 may rotate the substrate
100, via the support 306, about a center 308 of the substrate 100
or another suitable axis. The substrate driver 302 may be connected
to a substrate driver control unit, such as the controller 205, for
example, which may control the angular displacement, angular
velocity, and/or angular acceleration of the substrate 100. The
polishing apparatus 300 may further include a polishing arm 310
aligned in the horizontal plane approximately tangential to an edge
of the substrate 100 and supported by a frame 312. The frame 312
may be coupled at one end to a polishing head driver 309. In other
embodiments, the polishing arm 310 may be aligned differently, for
example, vertically or at an angle with respect to the horizontal
plane. The polishing arm 310 may include a polishing head section
314 (`head`). The polishing head 314 may include a backing or
polishing pad 316. The polishing pad 316 may be wheel-shaped, as
shown herein, or the polishing pad 416 may be relatively or
substantially planar in shape, as shown in FIG. 4. Other shapes may
be used. The polishing pad 316 may be moved toward or away from the
substrate 100 by an actuator (e.g., hydraulic actuator, pneumatic
actuator, servomotor, etc.) (not shown). Polishing tape 318, may
wrap around the polishing head 314, and guide rollers 320, 322 and
over the polishing pad 316, and be tensioned between spools 324,
326. The spools 324, 326 may be driven by spool drivers 328, 330
(e.g., servomotors), respectively. The spool drivers 328, 330, may
be moved continuously or indexed to precisely control the amount of
the polishing tape 318 that is advanced over the polishing head 314
from, for example, the spools 324, 326, in order to polish the
substrate notch 116.
[0053] In one or more embodiments, the abrasive component of the
polishing tape 318 may be made from many different materials, such
as diamond, aluminum oxide, silicon oxide, silicon carbide, etc.
Other materials may also be used. In some embodiments, abrasives
used may range, for example, from about 0.5 microns up to about 3
microns in size or 0.1 microns to 10 microns in size, although
other sizes may be used. Different widths of polishing tape 318
ranging from about 0.2 inches to about 1.5 inches may be used,
although other polishing tape widths may be used. In one or more
embodiments, the polishing tape 318 may be about 0.002 to about
0.02 inches thick and withstand about 1 to 5 lbs. in tension. Other
tapes having different thicknesses and tensile strengths may be
used. The spools 324, 326 may have a diameter of approximately 4
inches and be capable of holding about 5000 inches of polishing
tape 318, or may have a diameter of approximately 10 inches and be
capable of holding about 35,000 inches of polishing tape 318. Other
spool dimensions may be used. The spools 324, 326 may be
constructed from materials such as nylon, polyurethane, polyvinyl
difluoride (PVDF), etc. Other materials may also be used.
[0054] Turning to FIG. 4, an alternate embodiment of the apparatus
300 shown in FIG. 3 is provided. The difference between FIG. 3 and
FIG. 4 is that the wheel shaped polishing pad 316 is shown in FIG.
3 and the substantially planar polishing pad 416 is shown in FIG.
4. The different polishing pads 316 and 416 will be further
described below.
[0055] With reference to FIG. 5, a part of the substrate 100
containing the notch 116 is schematically illustrated, not to
scale. The notch 116 may include one or more notch sides 500. The
notch 116 may also include a first notch corner or node 502 and a
second notch corner or node 504. Each notch corner 502, 504 may be
positioned at the intersection of the notch side 500 and the outer
perimeter of the substrate 100. The notch 116 may further include a
notch center 506, positioned at the intersection of the one or more
notch sides 500. The notch center 506 may be used to align the
substrate 100 during processing. A notch depth 508 is also
indicated. As is apparent from the figure, the notch 116 may
exhibit large changes in curvature as it is traced from the first
notch corner 502 to the second notch corner 504, via the notch
sides 500 and notch center 506. For this reason, to improve notch
cleaning, it is advantageous to maintain consistent contact between
the polishing tape 318 and all regions of the notch 116 indicated
above.
[0056] FIG. 6 is a schematic perspective view, not to scale, of a
portion of an embodiment of the notch polishing apparatus 300 shown
in FIG. 3. For reasons of clarity, only the substrate 100, the
backing pad 316, the polishing tape 318, and the spools 324, 326
are shown. In addition, it should be pointed out that the
positioning of the spools 324, 326 shown herein is different than
in the embodiment of the notch polishing apparatus 300 shown in
FIG. 3.
[0057] However, the positioning of the spools 324, 326 may be
arranged in different ways and may not have a large effect on the
polishing of the notch 116. Additionally, as shown herein, the
polishing pad 316 may be supported on a polishing pad axle 332,
which may be mounted to the polishing head 314 or the support arm
310 in a manner that allows the polishing pad axle 332 to rotate
freely about an axis tangential to the substrate 100. The polishing
pad axle 332 may also be driven by a polishing pad driver (e.g., a
servomotor), not shown. The polishing pad axle 332 may be made out
of materials such as stainless steel or PEEK. Other materials may
be used. In some embodiments, the polishing pad 316 may be hollow
and filled with a pressurizable gas (e.g., air, nitrogen, carbon
dioxide, etc.) or liquid (e.g., hydraulic fluid), or other suitable
fluid.
[0058] In other embodiments, the polishing pad 316 may be filled
with a resilient material, such as polyurethane foam or silicone
rubber, for example. Other suitable materials may be used. In
either case, the polishing pad 316 may include an outer skin 334
(FIG. 7) made of a resilient material such as polyurethane,
silicone rubber or Viton, for example. Other suitable materials may
be used. As mentioned above with regard to FIG. 3, the polishing
pad 316 may be moved toward or away from the substrate 100 by an
actuator (not shown). When moved toward the substrate 100 by the
actuator, the polishing pad 316 may press the polishing tape 318
into the notch 116 and cause the polishing tape 318 to contact all
of the regions of the notch 116 (FIG. 5). The actuator may include
an actuator force sensor (not shown) or actuator pressure sensor
(not shown) for measuring a force or a pressure exerted by the
actuator on the polishing pad 316. The actuator may also be coupled
to an actuator control unit (not shown). The actuator control unit
may receive a signal from the actuator force sensor or actuator
pressure sensor indicative of the force or pressure exerted on the
polishing pad 316 by the actuator. The actuator control unit may
also regulate the force or pressure exerted by the actuator as a
function of this signal.
[0059] FIG. 7 is a schematic cross-sectional view of an embodiment
of the polishing pad 316 of FIG. 6, which is supported on the
polishing pad axle 332. The polishing pad axle 332 may rotate about
an axis A-A. The polishing pad 316 may be fixedly or rotationally
mounted to the polishing pad axle 332. In embodiments in which the
polishing pad 316 is filled with a gas or liquid, the polishing pad
316 and the polishing pad axle 332 may be connected to form a seal
between them. The seal may allow an interior region 336 of the
polishing pad 316 to withstand a fluid pressure of up to
approximately 80 lb/in.sup.2, for example, without leaking or
bursting. Other pressures may be used. The polishing pad axle 332
may include a fluid channel 338 that may lead from a pressurized
liquid or gas reservoir (not shown) to the interior region 336 of
the polishing pad 316. A pressure sensor (not shown) may be
situated in the interior region 336 or the fluid channel 338 or the
liquid or gas reservoir. A pressure control unit (not shown) may be
electrically connected to the pressure sensor and the liquid or gas
reservoir. The pressure control unit may receive a signal from the
pressure sensor that is indicative of a pressure in the liquid or
gas reservoir, a pressure in the fluid channel 338, or a pressure
in the interior region 336 of the polishing pad 316. The pressure
control unit may regulate the pressure in any or all of these areas
as a function of this signal.
[0060] In some embodiments, a portion of the polishing pad 316
under the outer skin 334 may include a ridge region 340. The ridge
region 340 may include a tip region 342 (FIG. 8), further described
below. The ridge region 340 may be substantially in relief (or
thinner) compared to the rest of the polishing pad and the tip
region 342. The relief portion may allow the polishing pad 316 to
better conform to the notch 116, and in particular to the first and
second nodes 502, 504 of the notch 116. In other embodiments, the
outer skin 334 may include ridges or an alternate profile (FIG.
10B) to apply the force to the polishing tape 318 and notch 116 in
a different manner. The polishing tape 318 may travel over at least
part of this ridge region 340 while being indexed or moved
continuously between the spools 324, 326.
[0061] FIG. 8 is an enlarged schematic cross-sectional view of the
polishing pad 316 of FIG. 7 in the region of FIG. 7 enclosed by a
dashed circle and labeled FIG. 8. As can be seen in this figure,
when the polishing pad 316 is moved in the direction of the
substrate 100, the polishing tape 318 may be pressed into the notch
116 by the ridge region 340, and in particular the tip region 342
of ridge region 340, which may have a shape corresponding to a
shape of the notch 116. In addition, the tip region 342 may be
provided with a radius that may ensure sufficient contact between
the polishing tape 318 and all of the sections of the notch 116
shown in FIG. 5. For example, if a minimum notch radius r.sub.1 is
0.035 inches and a thickness t of polishing tape 318 is
approximately 0.004 inches, then a maximum radius r.sub.2 of the
tip region 342 may be approximately 0.03 inches to ensure
sufficient contact between the polishing tape 318 and the notch
116. This contact may allow the polishing tape 318 to effectively
polish the substrate notch 116 when indexed between the spools 324,
326. Other tip region radii may be used.
[0062] Turning to FIGS. 9A and 9B, a schematic perspective view,
not to scale, of a portion of an embodiment of the notch polishing
apparatus 300 shown in FIG. 3 is provided. Similarly to FIG. 6, for
reasons of clarity, only the substrate 100, the polishing head 314,
the polishing pad 316, the polishing tape 318, and the spools 324,
326 are shown. In addition, it should be pointed out that unlike
the embodiment of the polishing apparatus 300 shown in FIG. 3, the
spools 324, 326 of the embodiment of the polishing apparatus 300
shown in FIGS. 9A and 9B may be considered to be part of the
polishing head 314. However, the other positioning of the spools
324, 326 may not be used during the operation of the notch
polishing apparatus 300. Further with respect to FIGS. 9A and 9B,
the polishing head 314 may be connected to the polishing-head
driver 309 via the support arm 310 and the frame 312 (see FIG. 3).
The polishing head driver 309 may rotate the polishing head 314,
and hence the polishing pad 316 (and in some embodiments the spools
324, 326,) about the substrate notch 116 in a plane approximately
perpendicular to major surfaces 102, 102' of the substrate 100.
This rotation of the polishing head 314 about the substrate notch
116 may be accomplished using a combination of vertical, horizontal
and rotational displacements of the polishing head 314 in a plane
perpendicular to the major surfaces 102, 102' of the substrate 100.
The actuator (not shown) used to move the polishing pad 316 toward
and away from the substrate notch 116 may also be used to
horizontally position the polishing pad 316 during the rotation of
the polishing head 314. The above-described rotation of the
polishing head 314 may allow the polishing apparatus 300 to
effectively clean and polish parts of the notch 116 adjacent to
major surfaces, i.e., to upper and lower major surface 102, 102',
of the substrate 100.
[0063] Specifically, FIG. 9A shows the polishing head 314 rotated
into a position allowing the parts of the notch 116 adjacent to the
lower major surface 102' of the substrate 100 to be cleaned and
polished. FIG. 9B, in turn, shows the polishing head 314 rotated
into a position allowing the parts of the notch 116 adjacent to the
upper major surface 102 of the substrate 100 to be cleaned and
polished.
[0064] FIG. 10A is a schematic plan view (not necessarily to scale)
of an embodiment of the polishing apparatus of the invention. The
polishing pad 316 may be supported on the polishing pad axle 332,
which in turn may be supported by a pair of support blocks 900,
902. As shown herein, in some embodiments the polishing pad 316 may
have a different profile compared to the polishing pad 316
described above with respect to FIGS. 7 and 8, for example. As
indicated by the "raised" portion of the outer skin 334 covering
the ridge region, the ridge region may just include the tip region,
instead of the relief portion and the tip region shown in FIGS. 7
and 8. Polishing tape 318 (depicted in cross section such that the
length of the polishing tape 318 would extend into and out of the
page) may be interposed between the polishing pad 316 and the
substrate 100, such that the polishing pad 316 may press the
polishing tape 318 into and/or against the notch 116. Support
blocks 900, 902 may have guides 904, 906, respectively, into which
polishing tape 318 may be threaded. Guides 904, 906 may prevent
side to side motion of the polishing tape 318 (e.g., motion
perpendicular to the plane of rotation of the polishing pad 316 and
in the plane of the page) and thus prevent the polishing tape 318
from slipping out from between the polishing pad 316 and the notch
116. Such prevention of side to side motion may be effected by the
bottoms 904a and 906a of the guides 904 and 906, respectively. The
sideways motion of the polishing tape 318 may be halted by the
contact of the polishing tape 318 with either of the bottoms 904a,
906a. Support blocks 900, 902 may be made from metals, polymeric
materials and/or any other material which is strong enough to hold
the polishing pad axle 332 and which may be made smooth enough to
allow the polishing tape 318 to move freely across a surface of the
guides 904, 906 without sustaining an undesirable amount of wear
over a predetermined period of time. Such a predetermined period of
time may be, for example, the effective lifetime of grit on a
polishing surface of the polishing tape 318.
[0065] FIG. 10B depicts another embodiment of the polishing
apparatus of FIG. 10A. In this embodiment, the guides 904, 906 may
be attached to the support blocks 900, 902, rather than formed in
the support blocks 900, 902. In yet other embodiments (not shown),
the guides 904, 906 may be separate from (e.g., not mounted on)
support blocks 900, 902. Guides 904 and 906 may be mounted in any
suitable position and/or orientation which is effective to prevent
the polishing tape 318 from moving out from between polishing pad
316 and notch 116, thereby preventing the polishing pad 316 from
making direct contact with the notch 116.
[0066] The guides 904, 906, as depicted in FIGS. 10A and 10B, are
located such that a plane of the major surface 102 of the substrate
100 intersects the guides 904, 906, but the guides 904, 906 may be
located in any plane and in any location which is effective to
prevent the polishing tape 318 from moving out from between
polishing pad 316 and notch 116. In other embodiments, more than
two guides may be used in more than one plane.
[0067] FIG. 10C is a schematic side view of one embodiment of the
polishing apparatus depicted in FIG. 10A. In FIG. 10C, it may be
seen that the polishing tape 318 may extend from a tape source,
such as the spool 324 shown in FIG. 3, around the polishing pad
316, and to a tape take-up, such as the spool 326 shown in FIG. 3.
Polishing tape 318 is depicted in FIG. 10C as folded over the
polishing pad 316 such that only one half of the polishing tape 318
is visible, the other half being obscured by the visible portion of
the polishing tape 318 and the polishing pad 316. An edge of the
polishing pad 316, obscured by the polishing tape 318 is indicated
by dotted line 316a. In FIG. 10C, it may also be seen that an edge
318a of polishing tape 318 may pass through guide 906. The
polishing tape edge 318a is depicted in dotted line form where the
polishing tape edge 318a passes through and is obscured by the
guide 906. The bottom of guide 906 is indicated by a dashed line
906a.
[0068] In operation, back and forth motion of the polishing tape
318 (e.g., motion having a component which is perpendicular to a
plane of rotation of the polishing pad 316) may be stopped and/or
restrained by a bottom 906a of the guide 906 and a mirror image
bottom and guide on the other side of (and obscured by) polishing
pad 316. The back and forth motion may also be described as motion
which would tend to move the polishing tape edge 318a (or a mirror
image edge which is obscured in FIG. 10C) of polishing tape 318
between the polishing pad edge 316a and the notch 116, such that
the polishing pad 316 may contact the notch 116 of the substrate
100 directly. Such restraint of motion may prevent the polishing
tape 318 from moving from between the polishing pad 316 and the
notch 116 in the substrate 116. The surfaces of guides 906, 908 may
be smoothened or polished to reduce wear on the polishing tape 318
and on the guides 904, 906. In some embodiments the direction of
the polishing tape 318 movement may be reversible, such that the
polishing tape source may become the polishing tape take-up and the
polishing tape take-up may become the polishing tape source. In
other embodiments, the polishing tape may be a continuous loop of
polishing tape.
[0069] Turning to FIG. 11, a schematic perspective view of an
exemplary embodiment of the polishing pad 416 shown in FIG. 4 is
depicted. The polishing pad 416 may further include a notch
polishing pad 418. The notch polishing pad 418 may have a
protruding portion 420, whose shape roughly corresponds to the
shape of the substrate notch 116. The notch polishing pad 418 may
be a contoured pad made of a soft material, such as polyurethane,
for example. Other suitable materials may be used. In some
embodiments, the material making up the notch polishing pad 418 may
have a hardness less than about Shore A 70 durometer, for example.
However, materials having different hardnesses may be employed. The
polishing pad 416 may be made of soft materials or rigid materials.
The notch polishing pad 418 may be press-fitted to the polishing
pad 416 or may be attached to the polishing pad 416 in another
suitable manner. The notch polishing pad 418 may be easily replaced
with a differently-shaped notch polishing pad in order to polish
notches having a different shape than that of the notch 116, shown
herein. In other embodiments, the notching polishing pad 418 and
the polishing pad 416 may be integrally formed as a single
continuous pad. The polishing pad 416 may also includes slots 422,
424 adapted to guide the polishing tape 318 as the polishing tape
318 is advanced through the substrate notch 116. The protruding
portion 420 of the notch polishing pad 418 may conform to the shape
of the notch 116 when pressed into the notch 116. The conformance
may thereby cause the polishing tape 318 to contact the notch
corners 502, 504, the notch sides 500, and the notch center 506,
shown in FIG. 5.
[0070] Turning to FIG. 12, a schematic perspective view of part of
the embodiment of the polishing apparatus 400 shown in FIG. 4 is
provided. As described above, the polishing head 314, which may be
supported by the support arm 310, may include the polishing pad 416
and the notch polishing pad 418 (obscured in FIG. 12 by the
polishing tape 318, and shown above in FIG. 11), and guide rollers
320, 322. The polishing tape 318 may wrap around the polishing head
314, that is, around guide roller 320, notch polishing pad 418, and
guide roller 322, while simultaneously being tensioned between
spool 324 and spool 326. As is apparent from the figure, the
protruding portion 420 of the notch polishing pad 418 may have a
cross section similar in shape to the substrate notch 116. As
described above, and shown herein, the polishing tape 318 may cover
this protruding portion 420 when wrapped around the polishing head
314 and tensioned between the spools 324, 326.
[0071] As described above with respect to FIG. 3, the polishing pad
416 may be moved in a direction towards or away from the substrate
100 by an actuator (not shown). In operation, when the polishing
pad 416 is moved towards the substrate 100 by the actuator, the
notch pad protruding portion 420 may contact the substrate notch
116. As the protruding portion 420 contacts the notch 116, it may
cause the section of polishing tape 318 overlaying the protruding
portion 420 to conform to the shape of the notch 116 and contact
all parts of the notch 116 (i.e. notch sides 500, first and second
corners 502, 504, and notch center 506). The conformance of the
polishing tape 318 to the shape of the notch 116 may allow the
polishing tape 318 to effectively clean and polish the notch
116.
[0072] Turning to FIG. 13, a schematic cross-sectional view of an
exemplary embodiment of the polishing pad 416 shown in FIGS. 11 and
12 is provided. The conformance of the protruding portion 420 of
the notch polishing pad 418 to the shape of the substrate notch 116
is shown more clearly herein.
[0073] Turning to FIG. 14, a schematic cross-sectional view of an
alternative embodiment of a relatively or substantially planar
polishing pad 516 is provided. Similarly to the embodiment shown in
FIG. 13, the polishing pad 516 may include slots 518, 520, adapted
to guide the polishing tape 318. The notch polishing pad 522 and
polishing pad 516 may be made of the same or similar materials as
the notch polishing pad 418 and polishing pad 416 described above
with respect to FIG. 11. Other materials may be used. As described
above, the notch polishing pad 522 may include a protruding portion
524, which may conform to the shape of substrate notch 116 when the
notch polishing pad 522 is pressed into the substrate notch 116. In
the embodiment shown herein, the notch polishing pad 522 may also
include a bore 526 or through-hole. In some embodiments, the bore
526 may extend along an entire length dimension of the notch
polishing pad 522, and/or the bore 526 may have a circular
cross-section.
[0074] Other suitably shaped cross-sections may be used. In some
embodiments, the bore 526 may be hollow. In some embodiments, the
bore 526 may be filled with a material having greater or lesser
elasticity than that of the notch polishing pad 522. The bore 526
may allow the protruding portion 524 of the notch polishing pad 522
to more effectively conform to the shape of the notch 116, when the
protruding portion 524 is pressed into or contacts the notch
116.
[0075] Turning to FIG. 15, a schematic cross-sectional view of
another exemplary embodiment of a polishing pad 616 is provided.
The polishing pad 616 may be held by a support arm 614. The
polishing pad 616 may include a notch polishing pad 618 and slots
620 and 622 for guiding the polishing tape 318. The notch polishing
pad 618 and polishing pad 616 may be made of the same materials as
the notch polishing pad 418 and polishing pad 416, described above
with respect to FIG. 11. Other materials may be used. The notch
polishing pad 618 may also include a protruding portion 624 and
plateau regions 626, 628. The shape of the protruding portion 624
may substantially correspond to the shape of the substrate notch
116. The height h of the protruding portion 624 may be the distance
between one of the plateau region 626, 628 and a rounded tip 630 of
the protruding portion 624. The polishing pad 616 may be moved in a
direction toward, and in a direction away from, the substrate notch
116 by an actuator (not shown). The actuator may press the
protruding portion 624 into contact with the substrate notch 116.
When the protruding portion 624 contacts the substrate notch 116,
the protruding portion 624 may conform to the shape of the
substrate notch 116, and may cause the polishing tape 318 to
contact the notch corners 502, 504, the notch sides 500, and the
notch center 506 (FIG. 5). In some embodiments, the height h of the
protruding portion 624 may be slightly larger than a typical notch
depth (see FIG. 5). Since the notch depth may vary on different
substrates 100, the height h of the protruding portion 624 may
allow the notch polishing pad 618 to adapt to various substrate
notch 116 heights. The plateau regions 626, 628 may be oriented in
a direction approximately perpendicular to a radius (not shown) of
the substrate 100 bisecting the substrate notch 116. However, the
plateau regions 626, 628 may also be oriented in a direction not
perpendicular to the radius of the substrate 100 bisecting the
substrate notch 116. When the protruding portion 624 of the notch
polishing pad 618 is pressed into contact with the substrate notch
116, the plateau regions 626, 628 may allow the polishing tape 318
to make effective contact with the notch corners 502, 504 (FIG. 5),
and effectively polish them.
[0076] The slots 620, 622 of the notch polishing pad 618 may guide
and approximately center the polishing tape 318 on the protruding
portion 624, as the polishing tape 318 is advanced through the
substrate notch 116. The slots 620, 622 may allow the polishing
tape 318 to be easily conformed to, and pushed into contact with,
the substrate notch 116 by the protruding portion 624 of the notch
polishing pad 618.
[0077] Turning to FIG. 16, a schematic cross-sectional view of
another embodiment of a polishing pad 716 including a notch
polishing pad 718 having a bore or through-hole 720 is provided.
The notch polishing pad 718 shown herein may be made from the same
or similar materials having substantially similar elastic
properties as the notch polishing pad 418 shown in FIG. 11. Other
materials may be used. The notch polishing pad 718 may include a
protruding portion 722 with a shape corresponding to that of the
substrate notch 116, and may have plateau regions 724, 726 for
effectively conforming the polishing tape 318 to the notch corners
502, 504 (FIG. 5). In addition, the polishing pad 716 may be made
of the same or substantially similar materials as the polishing pad
416 described above with respect to FIG. 11. In some embodiments,
the height h of the protruding portion 722 may be slightly larger
than a typical notch depth, in order to allow the notch polishing
pad 718 to adapt to the shapes of various substrate notches 116.
Similarly to the bore 526 shown in FIG. 14, in one or more
embodiments, the bore 720 shown herein may extend along an entire
length dimension of the notch polishing pad 718, and/or the bore
720 may have a circular cross-section. The cross-section of the
bore 720 may have other suitable shapes. As described above, in
some embodiments, the bore 720 may be hollow. In other embodiments,
the bore 720 may be filled with a material having greater or lesser
elasticity than that of the notch polishing pad 718. The bore 720
may allow the protruding portion 722 on the notch polishing pad 718
to more effectively conform to the shape of the substrate notch
116, when the protruding portion 722 is pressed into contact with
the substrate notch 116.
[0078] An exemplary method 1700 for cleaning and polishing the
substrate notch 116 is provided in FIG. 17. In step S1710, the
substrate 100 may be positioned and secured on the support. Then,
in step S1720, the substrate 100 is rotated until the notch 116 is
in alignment with the polishing head 314, i.e., in alignment with
the ridge section 340 of the polishing pad 316. In step S1730, the
polishing pad 316 is then moved in the direction of the substrate
100 by an actuator (not shown), until the tip region 342 of the
ridge region 340 of the polishing pad 316 is in contact with the
substrate notch 116, and presses the polishing tape 318 against the
substrate notch 116. In step S1740, the polishing tape 318 may then
be advanced by spool driver 328, 330 e.g., either of spools 324,
326 may be used as a take-up spool and a supply spool. As the
polishing tape 318 is advanced on the polishing pad 316 and through
the substrate notch 116, in some embodiments, the polishing pad 316
may rotate with a circumferential speed substantially equal to a
rate of advance of the polishing tape 318. This means that the
polishing tape 318 may advance on the polishing pad 316 without
substantial slippage, and that the friction between the polishing
pad 316 and the polishing tape 318 may include substantially
rolling friction and almost no sliding friction. The advantage of
rolling friction between the polishing pad 316 and a back side of
the polishing tape 318 over sliding friction between the same may
be a lower required tension of the polishing tape 318, more
reliable tracking of the polishing tape 318, less wear to the back
side of the polishing tape 318 and to the polishing pad 316, less
heat generation, and less damage (e.g., plastic deformation) to the
polishing tape 318 due to overheating.
[0079] Further with respect to the method 1700 for cleaning and
polishing the substrate notch 116, the pressure with which the
polishing tape 318 is pressed into contact with, and against, the
substrate notch 116 may be determined by the force or pressure
applied to the polishing pad 316 by the actuator, the pressure of
the fluid in the polishing pad 316, and/or the resilience of the
polishing tape 318. As the polishing tape 318 is advanced over the
substrate notch 116, films and imperfections on the substrate notch
116 may be removed and eliminated by abrasion. The force or
pressure applied by an actuator, and/or the pressure of the fluid
in the polishing pad 316, may be adjusted by an actuator control
unit and a pressure control unit, respectively, as needed. In step
S1750, a polishing-head driver may rotate the polishing head 314
about the substrate notch 116 in a plane approximately
perpendicular to major surfaces 102, 102' of the substrate 100, in
order to effectively clean and polish parts of the substrate notch
116 adjacent to major surfaces 102, 102' of the substrate 100.
During the above-described rotation of the polishing head 314, the
pressure of the fluid in the polishing pad 316 may be adjusted by a
pressure control unit to effectively conform the shape of the ridge
region 340 and tip region 342 to changing geometry of the substrate
notch 116. The speed, direction, tension, pressing force, etc. of
the polishing tape 318 may be adjustable, as may be the rotational
displacement, speed, and/or acceleration of the polishing head 314
about the substrate 100. For instance, the polishing tape 318 may
be advanced at one speed for a certain length, and then another
speed for another length. In addition, the polishing tape 318 may
be translated or oscillated, or both, with constant or variable
tensions and pressing forces.
[0080] Turning to FIG. 18, a second method 1800 for cleaning and
polishing the substrate notch 116 is provided. The method of FIG.
18 is similar to the method described with reference to FIG. 17,
but has the additional step of threading polishing tape through
guides of a polishing pad as described below.
[0081] In step S1802 the substrate 100 may be positioned and
secured on the support. In step S1804, the substrate 100 is rotated
until the substrate notch 116 is in alignment with the polishing
head 314, e.g., in alignment with the ridge section 340 of the
polishing pad 316. In step S1806, which may be performed at any
time prior to step S1808, the polishing tape 318 may be threaded
through guides 904 and 906 and around the polishing pad 316. Such
threading may be performed manually, or automatically. In step
S1808, the polishing pad 316 may then be moved in the direction of
the substrate 100 by an actuator, until the tip region 342 of the
ridge region 340 of the polishing pad 316 is in the substrate notch
116 and presses the polishing tape 318 against the substrate notch
116. In step S1810, the polishing tape 318 may then be advanced by
spool driver 328, 330, e.g., either of spools 324, 326 may be used
as a take-up spool and a supply spool. All of the variations
described above with respect to step S1740 of FIG. 17 may be used
with the method 1800 of FIG. 18. In step S1812, a polishing head
driver may rotate the polishing head 314 about the substrate notch
116 in a plane approximately perpendicular to major surfaces 102,
102' of the substrate 100, in order to more effectively clean and
polish parts of the notch 116 adjacent to major surfaces 102, 102'
of the substrate 100. Once again, all of the variations described
above with respect to method step S1750 (FIG. 17) are available for
use in the method 1800 of FIG. 18.
[0082] 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, in some embodiments, the polishing-tape guides may
project from close to the outer skin 334 of the polishing pad 316
and run concentrically with the tip region 342. The polishing tape
guides may keep the polishing tape 318 approximately centered with
respect to the tip section 342 of the ridge section 340, while the
polishing tape 318 is indexed through the substrate notch 116.
Furthermore, steps, such as applying a coating to the outer skin
334 over the ridge region 340, roughening the outer skin 334 over
the ridge region 340, or otherwise increasing a tackiness of the
outer skin 334 over the ridge region 340, may be undertaken, in
order to increase the coefficient of friction between the backing
side of the polishing tape 318 and the polishing pad 316 and
decrease a likelihood of slippage of the polishing tape 318 on the
polishing pad 316 during notch polishing.
[0083] 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 claim.
* * * * *