U.S. patent application number 12/039418 was filed with the patent office on 2008-08-28 for methods and apparatus for cleaning a substrate edge using chemical and mechanical polishing.
This patent application is currently assigned to APPLIED MATERIALS, INC.. Invention is credited to Yufei Chen, Wei-Yung Hsu, Sen-Hou Ko, Zhenhua Zhang.
Application Number | 20080207093 12/039418 |
Document ID | / |
Family ID | 39716431 |
Filed Date | 2008-08-28 |
United States Patent
Application |
20080207093 |
Kind Code |
A1 |
Ko; Sen-Hou ; et
al. |
August 28, 2008 |
METHODS AND APPARATUS FOR CLEANING A SUBSTRATE EDGE USING CHEMICAL
AND MECHANICAL POLISHING
Abstract
Methods and apparatus are provided for concurrently chemically
and mechanically polishing a substrate edge. The invention includes
a substrate support adapted to rotate a substrate; a polishing head
adapted to contact an edge of the substrate, the polishing head
including a first channel adapted to apply a first fluid to the
edge of the substrate; a second channel adapted to direct a second
fluid onto a major surface of the rotating substrate; and a third
channel adapted to direct a third fluid at the major surface of the
substrate and to prevent the second fluid from diluting the first
fluid. Numerous other aspects are provided.
Inventors: |
Ko; Sen-Hou; (Sunnyvale,
CA) ; Zhang; Zhenhua; (San Jose, CA) ; Chen;
Yufei; (San Jose, CA) ; Hsu; Wei-Yung; (Santa
Clara, CA) |
Correspondence
Address: |
DUGAN & DUGAN, PC
245 Saw Mill River Road, Suite 309
Hawthorne
NY
10532
US
|
Assignee: |
APPLIED MATERIALS, INC.
|
Family ID: |
39716431 |
Appl. No.: |
12/039418 |
Filed: |
February 28, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60892237 |
Feb 28, 2007 |
|
|
|
Current U.S.
Class: |
451/44 ; 451/285;
451/37; 451/446 |
Current CPC
Class: |
B24B 57/02 20130101;
B24B 9/065 20130101 |
Class at
Publication: |
451/44 ; 451/37;
451/285; 451/446 |
International
Class: |
B24B 9/02 20060101
B24B009/02; B24B 57/02 20060101 B24B057/02 |
Claims
1. An apparatus for concurrently chemically and mechanically
polishing a substrate edge, the apparatus comprising: a substrate
support adapted to rotate a substrate; a polishing head adapted to
contact an edge of the substrate, the polishing head including a
first channel adapted to apply a first fluid to the edge of the
substrate; a second channel adapted to direct a second fluid onto a
major surface of the rotating substrate; and a third channel
adapted to direct a third fluid at the major surface of the
substrate and to prevent the second fluid from diluting the first
fluid.
2. The apparatus of claim 1 wherein the first channel is further
adapted to apply the first fluid to the edge of the substrate where
the polishing head contacts the edge.
3. The apparatus of claim 1 wherein the polishing head includes one
or more sponges adapted to contact the edge of the substrate.
4. The apparatus of claim 3 wherein the first channel provides the
first fluid to the one or more sponges.
5. The apparatus of claim 1 wherein the polishing head includes a
pad.
6. The apparatus of claim 1 wherein the polishing head includes a
polishing tape.
7. The apparatus of claim 1 wherein the polishing head includes a
conformal backing plate.
8. The apparatus of claim 1 wherein the polishing head includes a
shaped backing plate.
9. The apparatus of claim 1 wherein the second fluid is deionized
water.
10. The apparatus of claim 1 wherein the shape of the third fluid
forms an arc surrounding the edge of the substrate contacted by the
polishing head and a portion of the major surface of the
substrate.
11. A system for concurrently chemically and mechanically polishing
a substrate edge, the system comprising: a substrate support
adapted to rotate a substrate; a polishing head adapted to contact
an edge of a substrate, the polishing head including a first
channel adapted to apply a first fluid to the edge of the
substrate; a second channel adapted to direct a second fluid onto a
major surface of the rotating substrate; a third channel adapted to
direct a third fluid at the major surface of the substrate and to
prevent the second fluid from diluting the first fluid; and a
controller adapted to operate the concurrent chemical and
mechanical polishing of the edge of the substrate.
12. The system of claim 11 wherein the shape of the third fluid
forms an arc surrounding the edge of the substrate contacted by the
polishing head and a portion of the major surface of the
substrate.
13. The system of claim 12, further comprising a thin curved slit
nozzle adapted to form the arc shape of the third fluid.
14. The system of claim 11 wherein the third fluid is N.sub.2.
15. The system of claim 11 wherein the controller is adapted to
operate the direction of at least one of the second and third
fluids.
16. The system of claim 11 wherein the controller is adapted to
operate the application of the first fluid to the edge of the
substrate.
17. The system of claim 11 wherein the first channel is further
adapted to apply the first fluid to the edge of the substrate where
the polishing head contacts the edge.
18. The system of claim 11 wherein the polishing head includes one
or more sponges adapted to contact the edge of the substrate.
19. The system of claim 18 wherein the first channel provides the
first fluid to the one or more sponges.
20. A method for concurrently chemically and mechanically polishing
a substrate edge, the method comprising: rotating a substrate;
contacting an edge of the substrate with a polishing head; applying
a first fluid to the edge of the substrate via the polishing head;
directing a second fluid onto a major surface of the rotating
substrate; and directing a third fluid at the major surface of the
substrate, wherein the third fluid prevents the second fluid from
diluting the first fluid.
21. The method of claim 20 further comprising: arcing the third
fluid such that the arc surrounds the edge of the substrate
contacted by the polishing head and a portion of the major surface
of the substrate.
22. The method of claim 20 further comprising: rocking the
polishing head about the edge of the substrate.
23. The method of claim 20 further comprising: pressing a polishing
tape against the edge of the substrate via the polishing head.
24. The method of claim 20 further comprising: pressing a polishing
pad against the edge of the substrate via the polishing head.
25. The method of claim 20 wherein the polishing head includes at
least one sponge, and the first fluid is applied to the edge of the
substrate via the at least one sponge.
Description
[0001] The present application claims priority from U.S.
Provisional Patent Application Ser. No. 60/892,237 filed Feb. 28,
2007, entitled "SUBSTRATE EDGE BEVEL POLISHING SYSTEMS AND METHODS
USING CHEMICALS FOR MATERIAL REMOVAL" (Attorney Docket No.
11445/L).
CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] The present application is also 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 SUBSTRATE" (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. 60/939,350, 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);
[0012] 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);
[0013] 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);
[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. 60/939,212, 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);
[0016] U.S. Patent Application Ser. No. 60/99,228, filed May 21,
2007, entitled "METHODS AND APPARATUS FOR POLISHING A NOTCH OF A
SUBSTRATE BY SUBSTRATE VIBRATION" (Attorney Docket No. 11952/L);
and
[0017] 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
[0018] The present invention relates generally to electronic device
processing, and more particularly to methods and apparatus for
cleaning an edge of a substrate.
BACKGROUND OF THE INVENTION
[0019] During electronic device manufacturing, undesirable
materials may build up on the edge of a substrate. The materials
may include dielectrics, photoresist and metals used in IC
manufacture. Therefore, it may be desirable to clean or polish the
bevel and edge of the substrate to remove these materials. What is
needed are systems, methods and apparatus for cleaning the edge of
substrates without damaging the major surfaces of the
substrates.
SUMMARY OF THE INVENTION
[0020] In aspects of the invention, an apparatus is provided for
concurrently chemically and mechanically polishing a substrate
edge. The apparatus comprises a substrate support adapted to rotate
a substrate; a polishing head adapted to contact an edge of the
substrate, the polishing head including a first channel adapted to
apply a first fluid to the edge of the substrate; a second channel
adapted to direct a second fluid onto a major surface of the
rotating substrate; and a third channel adapted to direct a third
fluid at the major surface of the substrate and to prevent the
second fluid from diluting the first fluid.
[0021] In other aspects of the invention, a system is provided for
concurrently chemically and mechanically polishing a substrate
edge. The system comprises a substrate support adapted to rotate a
substrate; a polishing head, adapted to contact an edge of a
substrate, the polishing head including a first channel adapted to
apply a first fluid to the edge of the substrate; a second channel
adapted to direct a second fluid onto a major surface of the
rotating substrate; a third channel adapted to direct a third fluid
at the major surface of the substrate and to prevent the second
fluid from diluting the first fluid; and a controller adapted to
operate the concurrent chemical and mechanical polishing of the
edge of the substrate.
[0022] In yet other aspects of the invention a method is provided
for concurrently chemically and mechanically polishing a substrate
edge. The method includes the steps of (1) rotating a substrate;
(2) contacting an edge of the substrate with a polishing head; (3)
applying a first fluid to the edge of the substrate via the
polishing head; (4) directing a second fluid onto a major surface
of the rotating substrate; and (5) directing a third fluid at the
major surface of the substrate, wherein the third fluid prevents
the second fluid from diluting the first fluid.
[0023] 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
[0024] FIG. 1 is a schematic illustration of a cross-section of a
portion of a substrate.
[0025] FIG. 2 is a schematic illustration depicting an example
embodiment of an edge cleaning system according to the present
invention.
[0026] FIG. 3 is a perspective view depicting another example
embodiment of an edge cleaning system according to the present
invention.
[0027] FIG. 4 is a side view of a polishing unit according to the
present invention.
[0028] FIG. 5 is a front view of a polishing unit according to the
present invention.
[0029] FIG. 6 is a flow chart depicting an example application
method of embodiments of an edge cleaning system according to the
present invention.
DETAILED DESCRIPTION
[0030] The present invention provides improved methods 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 pad or film contacting the substrate edge via a
polishing head and by application of chemicals onto the substrate
edge, as the substrate is rotated or otherwise moved (e.g.,
oscillated). As the substrate rotates, deionized water (hereinafter
"DI water") may be applied to the major surface (non-beveled and
non-edge surface) of the substrate to prevent potential
contamination and to remove material that accumulates as a result
of polishing/cleaning. However, it may be undesirable for the DI
water to contact the polishing head or dilute the chemicals.
According to the present invention, a curtain of fluid, and in a
preferred embodiment a gas, such as N.sub.2, is directed at the
major surface of the substrate such that the gas prevents the DI
water from contacting the polishing head and/or diluting the
polishing chemicals. In some embodiments the curtain of gas may be
curbed to form an arc surrounding the area on the substrate to be
polished, such that the interior of the arc faces the polishing
head. In some embodiments, the interior of the arc may face the DI
water supply to contain the DI water and push it away from the
polishing head.
[0031] 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'. 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] Turning to FIG. 2, a schematic illustration of an example
embodiment of a polishing head system 200, including a polishing
head 201, adapted to polish the edge 104 of a substrate 100 is
provided. The substrate 100 may be held or supported and rotated by
a vacuum chuck 202, for example. Other suitable substrate support
and rotation means may be used. For example, the substrate 100 may
be rotated by driver rollers and guide rollers, etc. The polishing
head 201 may include a backing pad 204, a roller, and/or an
inflatable pad. In either case, the pad, roller and/or inflatable
pad may be soft and/or include or develop contours to conform to
the shape of the substrate edge 104. In some embodiments, the
backing pad 204 may also include abrasive particles and be used to
polish the substrate edge 104. Additionally or alternatively, the
backing pad 204 may be pressed against a polishing tape 206, used
to polish the substrate edge 104. The system 200 may further
include an actuator 208 (e.g., a pneumatic slide, hydraulic ram,
servo motor driven pusher, etc.). As the substrate 100 rotates, the
actuator 208 may press the backing pad 204, and hence the polishing
tape 206, against the substrate edge 104. Alternatively or
additionally, the actuator 208 may be adjustable, and may also be
used to push the entire head 201 towards the substrate 100.
Alternatively, a biasing device (e.g., a spring) may be employed to
mount the pad 204 to the head 201, to provide flexible/dynamic
counter pressure to the pad 204. In some embodiments, the substrate
100 may be in contact with the polishing tape 206 for about 15 to
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 polishing
tape 206, and the substrate edge 104, as the polishing tape 206 is
pressed against the substrate edge 104 by the backing pad 204,
combined with the particular rotational speed of the substrate 100,
may provide relative movement between the polishing tape 206 and
the substrate edge 104, resulting in polishing the substrate edge
104. Depending on the amount of force applied by the actuator 208,
the resiliency of the pad 204 selected, the amount of inflation of
an inflatable pad, and/or the amount of tension on the polishing
tape 206, a controlled amount of pressure may be applied to polish
the substrate edge 104. Thus, the system 200 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.
[0033] The pad 204 may be made of material such as, for example, an
acetal resin (e.g., Delrin.RTM. manufactured by DuPont
Corporation), PVDF, polyurethane closed cell foam, silicon rubber,
etc. Other suitable materials may be used. Such materials may have
resilience or an ability to conform that is a function of the
thickness or density of the pad 204. The material may be selected
based upon its resilience. The desired resilience may be selected
based upon the type of polishing required.
[0034] In some embodiments, the degree to which the pad 204 may
conform to the substrate edge 104 may be adjustable. For example,
the pad 204 may be, or include, an inflatable bladder, as described
in Application Ser. No. 60/939,333 (Attorney Docket No. 11567/L),
cited above, which may be inflatable by air, liquid or other fluid.
The amount of fluid filling the pad 204 may be adjusted, such that
the pad 204 may suitably conform to the substrate edge 104.
[0035] The substrate 100 may be rotated, for example, in a
horizontal plane. The substrate edge 104 may be aligned with, or
normal to, the polishing tape 206, pad 204 and/or polishing head
201. 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.
[0036] In the embodiment described herein, as the substrate 100
rotates, the polishing head 201 may rock around the substrate edge
104 to polish the entire edge 104. The angle of rocking may
include, for example, plus or minus 90 degrees. Other rocking
angles may be used. In operation, this is achieved by angularly
translating the head 201, and consequently the backing pad 204 and
polishing tape 206 in contact with, and contoured to, the substrate
edge 104, around an axis that is tangential to the outer edge 110
of the substrate 100 as it is rotated. In some embodiments, the
head 201 may be adapted to continuously or intermittently oscillate
between the various positions. The head 201 may be moved by drivers
(not shown) under the direction of a programmed or user operated
controller 210 (shown in FIG. 3). Alternatively, the head 201 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 201 is oscillated (as described above), as
well as rotated circumferentially around the substrate 100. In some
embodiments, the key parameters to control the edge polishing area
may be the angle of rocking, the center of rotation for rocking,
and the contour of the backing pad.
[0037] In some embodiments, fluids or chemicals may be used to aid
in the polishing or washing away of accumulated particles, and may
be delivered to the substrate edge 104, as further described below
with respect to FIG. 4.
[0038] As described above, in some embodiments, the controller 210
(shown in FIG. 3), (e.g., a programmed computer, a programmed
processor, a gate array, a logic circuit, an operator directed
valve system, an embedded real time processor, etc.) may control
the driver(s) used to rotate the substrate 100 and the actuator 208
used to push the pad 204 against the substrate edge 104. Note that
the controller 210 may be coupled (e.g., electrically,
mechanically, pneumatically, hydraulically, etc.) to each of a
plurality of actuators 208. Likewise, operation of the fluid
channels, described below with respect to FIG. 4, may also be under
the direction of the controller 210. Under direction of the
controller 210, various fluids may be selectively delivered to the
pads 204 and/or the substrate edge 104 via the fluid channels. The
controller 210 may be adapted to receive feedback signals from the
driver and/or actuator 208, that indicate the amount of energy
being exerted to drive the substrate 100 (e.g., rotate a vacuum
chuck holding the substrate 100) and/or actuate the actuator 208 to
push the pad 204, respectively. 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.
[0039] FIG. 3 is a perspective view depicting an example embodiment
of a substrate polishing system 300 according to the present
invention. The substrate polishing system 300 shown herein includes
three heads 302. Any number and type of heads 302 may be used in
any practicable combination. In addition, in such multi-head
embodiments, each head 302 may use a differently contoured backing
pad 204 (e.g., different contours of the strip, etc.). Any number
of heads 302 may be used concurrently, individually, and/or in a
sequence. The heads 302 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 pads 204 and/or polishing
tape 206 to polish different portions of the edge 104 of the
rotating substrate 100. The heads 302 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 any
suitable means so as to polish different portions of the substrate
edge 104. Different heads 302 may be used for different substrates
100 or different types of substrates 100.
[0040] Turning to FIG. 4, a side view of a polishing unit 400
according to the present invention is depicted. In the example
embodiment shown herein, the polishing unit 400 includes a
polishing head 402. The polishing head 402 may include a backing
plate 404, covered by a backing pad 406. In some embodiments the
backing plate may be shaped to mimic the shape of the substrate
while in other embodiments the backing plate may conform to the
shape of the substrate. In some embodiments the backing plate 404
may be coupled to the polishing head 402, while in other
embodiments the backing plate 404 may be integrally formed with the
polishing head 402. The backing pad 406 may be used to mechanically
polish the substrate edge 104. In some embodiments, as described
above, polishing tape 206 may be used to polish the substrate edge
104, and the backing pad 406 (or roller) may press the polishing
tape 206 against the substrate edge 104. The polishing unit 400 may
also include a nozzle 408, disposed at the substrate edge 104. The
nozzle 408 may be shaped as a thin curved slit. Other nozzle shapes
may be used. As described above, as the substrate 100 rotates, a
deionized water supply may direct deionized water onto the major
surface 102, 102 of the substrate 100, via a deionized water
channel 410, and the deionized water may be centrifugally pushed
out to the rest of the major surface 102, 102 of the substrate 100.
Additionally, while the substrate 100 rotates, the nozzle 408 may
dispense a curtain of fluid, such as N.sub.2 (whereby the curtain
of fluid is hereinafter referred to as "N.sub.2"). Other gases or
fluids may be used. For example, other inert gases may be used. The
shape of the thin slit nozzle 408 may provide a curtain of N.sub.2
between the substrate edge 104 and the polishing head 402 and pad
406. In some embodiments the shape of the nozzle 408 may provide a
curtain of N.sub.2 that may be curved or arced, such that the area
of the substrate 100 being polished, and a portion of the major
surface 102 of the substrate 100, is surrounded by the N.sub.2
curtain. This N.sub.2 curtain may prevent the deionized water from
contacting, and potentially damaging, the polishing head 402.
Additionally, the N.sub.2 curtain may also prevent the deionized
water from mixing with, and diluting, the chemicals (described
below and with respect to FIG. 5) used to clean and polish the
substrate edge 104. Alternatively, the N.sub.2 curtain may prevent
the chemicals (e.g., polishing chemicals) from contacting the major
surface 102 of the substrate 100. The chemicals may include, for
example, surfactant and/or other known cleaning chemistries.
[0041] While in the exemplary embodiment shown here, the nozzle 408
is positioned at a 90 degree angle with respect to the major
surface 102 of the substrate 100, in alternate embodiments the
nozzle may be positioned at a different angle with respect to the
major surface 102 of the substrate 100. For example, when the
nozzle 408 is perpendicular (or 90 degrees) to the major surface
102 of the substrate 100, the N.sub.2 curtain may also flow in a
perpendicular direction to the major surface 102 of the substrate
100. When the N.sub.2 curtain contacts with the major surface of
the substrate 100, it may flow towards both the polishing head 402
and the DI water, thereby essentially pushing both the chemicals
from the DI water to keep them separate. In another exemplary
embodiment, the nozzle 408 may be angled towards the DI water, such
that the N.sub.2 curtain pushes the DI water away from the
polishing head 402, further preventing chemical dilution, but may
have no effect on the chemicals contacting the substrate edge 104.
In yet another exemplary embodiment, the nozzle 408 may be angled
towards the polishing head 402, such that the DI water may be
allowed to flow towards the polishing head 402, to a certain
extent, but the chemicals are prevented from contacting the major
surface 102 of the substrate 100.
[0042] In some embodiments the chemicals may be applied to and/or
through the tape 206 and/or the pad 406 or roller. The backing
plate 404 may include one or more channels 502 adapted to drip or
spray the fluid directly onto or into the pads 204, 406.
Alternatively, the pad 406 may be inflatable and may include a
bladder (not shown) with a semi-permeable membrane that allows
fluid to be slowly released and transmitted to the polishing tape
206 (e.g., through the pad). In such embodiments, the pad 204, 406
may be covered by, made of, and/or include, material that absorbs
and/or retains the fluids used (e.g., polyvinyl alcohol (PVA),
etc.). In other embodiments, the chemicals may be sprayed directly
onto the substrate 100.
[0043] In an alternative embodiment, instead of a polishing pad 406
and/or in combination with the polishing pad 406, heating elements
(not shown) may be used to provide temperature assistance to
enhance the wet etch rate of the chemicals used to polish/clean the
substrate edge 104. The applied heat may be controlled at different
locations to control the resulting material removal profile. As
with the backing plate, the materials that enclose the heating
elements may be flexible/pliable materials such as rubber,
polyimide, etc.
[0044] Turning to FIG. 5, a front view of the polishing unit 400
described in FIG. 4, according to the present invention is
depicted. In some embodiments, the polishing unit 400 may also
include one or more sponges 500. The sponges 500 may be affixed to
the backing plate 404 and separated by the polishing pad 406. Any
suitable fixation means may be used. Other orientations may be
used. Additionally, more or fewer sponges 500 may be used. The
backing plate 404, as described above, may include one or more
channels 502 adapted to supply a cleaning/polishing chemical to one
or more of the sponges 500. In the particular example depicted
herein, each sponge 500 is coupled to a separate channel 502. In
some embodiments, for example, a single channel 502 may supply
chemicals to multiple sponges 500, or an individual sponge 500 may
receive chemicals from multiple channels 502. The chemicals may be
the same type or a different type. Different chemicals may be used
to more effectively clean/polish the substrate. In either case, the
sponge 500 may receive different chemicals in sequence, for
example. In other words, in the case of an individual sponge 500
and a single channel 502, a first chemical may flow through the
channel 502 and then a second, different chemical may flow through
the channel 502. In the case of the individual sponge 500 and
multiple channels 502, for example, a first chemical may flow
through a first channel 502 and then a second chemical may flow
through a second channel 502. In the case of the individual sponge
500 with multiple channels 502, the sponge 500 may alternatively
receive the chemicals from the multiple channels 502 at the same
time. In some embodiments, the same chemicals may be flowed through
the multiple channels 502 into the individual sponge 500 to
increase the flow of chemicals to the sponge 500 and subsequently
the substrate 100. In some embodiments, the same chemicals may be
flowed through multiple channels 502 into multiple sponges 500.
Alternatively, each sponge 500 may receive a different chemical.
Additionally, the amount of chemicals supplied to the sponges 500
may be controlled by the controller 210 or operator. The sponges
500 may contact and apply chemicals to the substrate edge 104
during the cleaning/polishing process. Additionally, as described
above, the polishing pad 406, similarly to the polishing tape
described above, may include abrasive materials of various minerals
and grit sizes, which provide a mechanical polishing action. The
thin curved slit nozzle 408 may be disposed at the substrate edge
104, between the substrate edge 104 and the sponges 500 and
polishing pad 406. While the substrate 100 rotates, as indicated by
the central curved arrow, and the deionized water is dispersed, the
nozzle 408 may dispense a curtain of N.sub.2, or other suitable gas
(e.g., an inert gas). As described above, the curtain of N.sub.2 is
applied between the substrate edge 104 and the sponges 500 and
polishing pad 406, and may prevent the deionized water from
contacting and potentially damaging the polishing head 402.
Additionally, the N.sub.2 curtain may also prevent the deionized
water from mixing with and diluting the chemicals used to clean and
polish the substrate edge 104. Additionally, the N.sub.2 curtain
may also prevent the chemicals from contacting the major surface of
the substrate.
[0045] Additionally, the present invention may employ gravity or
suction to cause the runoff not to contaminate or contact other
parts of the substrate 100 or system 200. Further, the substrate
edge 104 may be cleaned/polished by energy (e.g., megasonic
energy), which may be applied to the substrate edge 104 via fluid
carrying such energy.
[0046] Turning to FIG. 6, a flow chart illustrating an exemplary
method 100 of the present invention is depicted. Although five
discrete sequential steps are depicted, it should be understood
that any number of steps, sub-steps, and/or super-steps may be
combined or divided out and performed in different orders and/or
concurrently. The particular sequence depicted is merely
exemplarily and not necessarily required to perform various method
embodiments of the present invention. In other words, for example,
in some embodiments, all or some of the steps may be performed
concurrently or in reverse order. In step S102, a substrate is
rotated in a chuck, for example. In step S104, an edge of the
substrate is contacted with a polishing head. A first fluid, such
as a cleaning chemical, is applied to the edge of the substrate via
the polishing head in step S106. The chemical may be applied by
sponges included in the polishing head. In step S108 a second fluid
is directed onto a major surface of the rotating substrate. The
second fluid may be deionized water. As described above, as the
substrate rotates, the water may be centrifugally pushed out to the
rest of the major surface of the substrate. In step S110 a third
fluid is directed at the major surface of the substrate, such that
the third fluid prevents the second fluid from diluting the first
fluid. The third fluid may be a curtain of N2. As described above,
the curtain of N.sub.2 is applied between the substrate edge 104
and the polishing head 402, and may prevent the deionized water
from contacting and potentially damaging the polishing head 402.
Additionally, the N.sub.2 curtain may also prevent the deionized
water from mixing with and diluting the chemicals used to clean and
polish the substrate edge 104. Additionally, the N.sub.2 curtain
may also prevent the chemicals from contacting the major surface of
the substrate.
[0047] 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).
[0048] 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.
[0049] 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.
* * * * *