U.S. patent application number 15/666335 was filed with the patent office on 2018-02-08 for polishing pad, polishing apparatus and method for manufacturing polishing pad.
The applicant listed for this patent is San Fang Chemical Industry Co., Ltd.. Invention is credited to CHIN-WEI CHEN, CHUNG-CHIH FENG, YUNG-CHANG HUNG, PIN-HSIEN SUNG, WEN-CHIEH WU, I-PENG YAO.
Application Number | 20180036861 15/666335 |
Document ID | / |
Family ID | 61023193 |
Filed Date | 2018-02-08 |
United States Patent
Application |
20180036861 |
Kind Code |
A1 |
FENG; CHUNG-CHIH ; et
al. |
February 8, 2018 |
POLISHING PAD, POLISHING APPARATUS AND METHOD FOR MANUFACTURING
POLISHING PAD
Abstract
The present invention relates to a polishing pad with improved
slurry retention capacity, which includes a polishing layer. The
polishing layer includes an elastomer main body and a plurality of
titanium dioxide nanowires. Each of the titanium dioxide nanowires
is independent and is distributed evenly and randomly in the
elastomer main body. The present invention further provides a
polishing apparatus and a method for manufacturing the polishing
pad.
Inventors: |
FENG; CHUNG-CHIH; (Kaohsiung
City, TW) ; YAO; I-PENG; (Kaohsiung City, TW)
; HUNG; YUNG-CHANG; (Kaohsiung City, TW) ; SUNG;
PIN-HSIEN; (Kaohsiung City, TW) ; CHEN; CHIN-WEI;
(Kaohsiung City, TW) ; WU; WEN-CHIEH; (Kaohsiung
City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
San Fang Chemical Industry Co., Ltd. |
Kaohsiung City |
|
TW |
|
|
Family ID: |
61023193 |
Appl. No.: |
15/666335 |
Filed: |
August 1, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B24B 37/22 20130101;
B24D 3/346 20130101; B24B 37/24 20130101; B24D 3/344 20130101; B24D
18/0009 20130101; B24B 37/245 20130101 |
International
Class: |
B24B 37/24 20060101
B24B037/24; B24D 18/00 20060101 B24D018/00; B24B 37/22 20060101
B24B037/22 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 5, 2016 |
TW |
105125047 |
Claims
1. A polishing pad comprising: a polishing layer, wherein the
polishing layer comprises an elastomer main body; and a plurality
of titanium dioxide nanowires, wherein each of the titanium dioxide
nanowires is independent and is dispersed evenly and randomly in
the elastomer main body.
2. The polishing pad according to claim 1, wherein the polishing
layer further comprises a plurality of pores dispersed in the
elastomer main body.
3. The polishing pad according to claim 1, wherein the polishing
layer further comprises a nonwoven fabric.
4. The polishing pad according to claim 1, wherein a length of the
plurality of titanium dioxide nanowires is about 0.1 nm to about
100 nm.
5. The polishing pad according to claim 1, wherein a diameter of
the plurality of titanium dioxide nanowires is about 0.1 nm to
about 50 nm.
6. The polishing pad according to claim 1, wherein a ratio of the
plurality of titanium dioxide nanowires in the polishing layer is
about 0.1% to about 20% by weight.
7. The polishing pad according to claim 1, wherein a portion of the
plurality of titanium dioxide nanowires is exposed on a surface of
the polishing layer.
8. The polishing pad according to claim 2, wherein a portion of the
plurality of titanium dioxide nanowires is disposed in the
plurality of pores.
9. The polishing pad according to claim 1, wherein the polishing
layer further comprises a plurality of polishing particles evenly
distributed in the elastomer main body.
10. The polishing pad according to claim 1, further comprising a
buffer layer on a surface of the polishing layer.
11. The polishing pad according to claim 10, further comprising a
binder layer binding the polishing layer and the buffer layer.
12. The polishing pad according to claim 1, wherein the polishing
layer further comprises a polishing surface, and wherein the
polishing surface comprises a groove.
13. The polishing pad according to claim 1, further comprising an
adhesive layer on a surface of the polishing layer.
14. A polishing apparatus comprising: a polishing plate; a
substrate; the polishing pad according to claim 1, which is adhered
on the polishing plate for polishing the substrate; and slurry
contacting with the substrate for polishing.
15. A method for manufacturing the polishing pad according to claim
1, comprising: (a) providing an elastomer composition; (b)
providing the plurality of titanium dioxide nanowires; (c)
dispersing the titanium dioxide nanowires of the step (b) evenly
and randomly in the elastomer composition of the step (a); (d)
providing the polishing layer by curing the elastomer composition
to form the elastomer main body.
16. The method according to claim 15, further comprising coating
the elastomer composition randomly dispersed with the plurality of
titanium dioxide nanowires of the step (c) on a carrier before the
step (d), wherein the carrier is a release liner.
17. The method according to claim 16, wherein the carrier comprises
a polyethylene glycol terephthalate film, a polypropylene film, a
polycarbonate film, a polyethylene film, a polyethylene
terephthalate film, a release paper or a release fabric.
18. The method according to claim 19, wherein the carrier is
continuously provided.
19. The method according to claim 15, further comprising filling
the elastomer composition randomly dispersed with the plurality of
titanium dioxide nanowires of the step (c) in a cavity of a mold
before the step (d).
20. The method according to claim 15, further comprising immersing
a nonwoven fabric in the elastomer composition randomly dispersed
with the plurality of titanium dioxide nanowires of the step (c)
before the step (d).
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to a polishing pad, a
polishing apparatus, and a method for manufacturing the polishing
pad.
2. Description of the Related Art
[0002] A polishing process generally refers to a wear control for a
preliminary coarse surface in a process of chemical mechanical
polishing (CMP), which makes slurry containing fine particles
evenly dispersed on an upper surface of a polishing pad, and at the
same time places a substrate against the polishing pad and then
rubs the substrate repeatedly with the polishing pad in a regular
motion. The substrate may be a semiconductor, a storage medium
substrate, an integrated circuit, an LCD flat-panel glass, an
optical glass or a photoelectric panel. During the polishing
process, a polishing pad must be used to rub the substrate, thus
the quality of the polishing pad directly influences the polishing
effect to the substrate.
[0003] FIG. 1 shows a schematic view of a polishing apparatus with
a conventional polishing pad. The polishing apparatus 1 includes a
pressure plate 11, a mounting sheet 12, a substrate 13, a polishing
plate 14, a polishing pad 15 and slurry 16. The pressure plate 11
is positioned opposite to the polishing plate 14. The mounting
sheet 12 is adhered to the pressure plate 11 through a backside
adhesive (not shown) and is used for carrying and mounting the
substrate 13. The polishing pad 15 is mounted on the polishing
plate 14 and faces the pressure plate 11 for polishing the
substrate 13.
[0004] The operation manner of the polishing apparatus 1 is as
follows. First, the substrate 13 is mounted on the mounting sheet
12, and then both the pressure plate 11 and the polishing plate 14
are rotated and the pressure plate 11 is simultaneously moved
toward the polishing plate 14, such that the polishing pad 15
contacts the surface of the substrate 13. Accordingly, the
substrate 13 is polished by the polishing pad 15 with the
continuously supplemented slurry 16.
[0005] FIG. 2 shows a cross sectional view of a conventional
polishing pad. As disclosed in U.S. Pat. No. 5,578,362, the
polishing pad 2 includes a plurality of pores 22 and a resin 21. A
method for manufacturing the polishing pad 2 is filling a resin
composition (which is usually a foaming polymer formed by
thermoplastic polyurethane) into a columnar mold. After cooling and
solidifying, the polishing pad 2 is produced by cutting the cured
resin composition into slices. The polishing pad 2 has an
independent foam structure, which is often used in a polishing
process with a higher degree of planarity. However, the biggest
problem of the polishing pad 2 is that when filling the resin 21 in
the columnar mold, the resin 21 cannot be uniformly distributed in
the columnar mold due to the effect of surface tension. When
forming, such non-uniform distribution of the resin 21 in the
columnar mold results in varying sizes and uneven distribution of
the pores 22, which cannot be easily controlled. After the slicing
process, the pores 22 with varying sizes can be clearly seen on a
sliced surface of the polishing pad 2. Besides, the pores 22 are
not connected to each other, thus the slurry cannot easily flow
therethrough. When polishing, the slurry is unable to infiltrate
into the interior region of the polishing pad, thus reducing the
slurry retention capacity of the surface.
[0006] In another aspect, R.O.C. Patent Publication 200609315
discloses a porous chemical mechanical polishing pad with
component-filled pores. The polishing pad includes a polymeric
material, and the pores of the polishing pad are controlled by
limiting void spaces within the polymeric material matrix. At the
same time, liquid, solid or a mixture thereof is added for
improving polishing uniformity of the polishing pad. However, the
above method cannot easily control the sizes of the pores, and
small pores on a surface of the polishing pad may easily be filled
by polishing powder. The polishing pad is provided with poor slurry
retention capacity, which tends to cause scratches on the
substrate.
[0007] Therefore, it is required to develop a novel polishing pad
in the art field for overcoming the defect of non-uniform pore
distribution and poor slurry retention capacity in the
aforementioned polishing pad, thus improving its polishing
performance.
SUMMARY OF THE INVENTION
[0008] The present invention provides a specific polishing layer
having titanium dioxide nanowires for increasing hydrophilicity of
the polishing layer. As such, slurry can adhere to the titanium
dioxide nanowires, thus increasing slurry retention capacity of the
polishing layer.
[0009] The invention provides a polishing pad comprising: [0010] a
polishing layer, wherein the polishing layer comprises [0011] an
elastomer main body; and [0012] a plurality of titanium dioxide
nanowires, wherein each of the titanium dioxide nanowires is
independent and is dispersed evenly and randomly in the elastomer
main body.
[0013] The invention also provides a polishing apparatus
comprising: [0014] a polishing plate; [0015] a substrate; [0016]
the polishing pad according to the above, which is adhered on the
polishing plate for polishing the substrate; and [0017] slurry
contacting with the substrate for polishing.
[0018] The invention further provides a method for manufacturing
the polishing pad according to the above, comprising: [0019] (a)
providing an elastomer composition; [0020] (b) providing the
plurality of titanium dioxide nanowires; [0021] (c) dispersing the
titanium dioxide nanowires of the step (b) evenly and randomly in
the elastomer composition of the step (a); [0022] (d) providing the
polishing layer by curing the elastomer composition to form the
elastomer main body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 shows a schematic view of a polishing apparatus
having a conventional polishing pad.
[0024] FIG. 2 shows a cross sectional view of the conventional
polishing pad.
[0025] FIG. 3 shows a cross sectional view of a polishing pad
according to the present invention.
[0026] FIG. 4 shows a schematic view of a polishing apparatus
having the polishing pad according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0027] The invention provides a polishing pad comprising: [0028] a
polishing layer, wherein the polishing layer comprises [0029] an
elastomer main body; and [0030] a plurality of titanium dioxide
nanowires, wherein each of the titanium dioxide nanowires is
independent from each other and is dispersed evenly and randomly in
the elastomer main body.
[0031] The term "polishing pad" according to the present invention
refers to a pad adapted for abutting against a substrate to be
polished in a process of chemical mechanical polishing. The
polishing pad rubs the to-be-polished substrate repeatedly in a
regular motion with the cooperation of slurry containing small
particles, so as to wear a preliminary coarse surface of the
substrate into a smooth surface. The term "polishing layer" in the
present invention refers to an element of a polishing pad, which
element is adapted for contacting with and rubbing the substrate to
be polished. That is, the polishing layer is the element which
actually executes polishing with the cooperation of the slurry. The
polishing layer can be a single sheet, or can be laminated with
other elements into a sheet structure. With references to FIG. 3, a
polishing layer 3 according to the present invention includes an
elastomer main body 32 and a plurality of titanium dioxide
nanowires 31, with each of the titanium dioxide nanowires 31 being
independent and distributed evenly and randomly in the elastomer
main body 32.
[0032] The term "elastomer main body" in the present invention
refers to a main body made of an elastomer. The elastomer is a type
of polymer which has rubber-like characteristics. During the
polishing process, the elastomer main body provides polishing
function while preventing scratches on the surface of the substrate
to be polished.
[0033] In an embodiment of the present invention, the elastomer is
provided in an elastomer composition, with said composition
including a resin and a crosslinking agent.
[0034] The term "crosslinking agent" in the present invention
refers to a reagent which undergoes a crosslinking reaction with
the resin of the present invention, so as to cure the resin under
appropriate conditions. The type of the crosslinking agent can be
selected in accordance with the type of the resin.
[0035] A proper solvent for the elastomer composition includes
dimethyl formamide (DMF) or water. The elastomer can optionally
include an additive, such as a surfactant. A concentration of the
elastomer in the elastomer composition is preferably in a range of
about 2 wt % to about 60 wt %.
[0036] With references to FIG. 3, in a preferred embodiment of the
present invention, the polishing layer further includes a plurality
of pores 33 dispersed in the elastomer main body 32.
[0037] In a preferred embodiment of the present invention, the
elastomer main body and the plurality of pores can be provided by a
foaming resin simultaneously. The term "foaming resin" in the
present invention refers to a material containing a thermoplastic
resin and a thermodecomposing foaming agent. Preferably, the resin
includes at least one selected from a group consisting of
polyurethane, polyolefin, polycarbonate, polyvinyl alcohol, nylon,
elastic rubber, polystyrene, poly aromatic molecules,
fluorine-containing polymer, polyimide, crosslinked polyurethane,
crosslinked polyolefin, polyether, polyester, polyacrylate, elastic
polyethylene, polytetrafluoroethene, poly (ethylene terephthalate),
poly aromatic amide, polyarylalkene, polymethyl methacrylate, a
copolymer thereof, a block copolymer thereof, a mixture thereof,
and a blend thereof.
[0038] A manner of foaming the resin according to the present
invention can be chemically foaming or physically foaming, wherein
the chemically foaming manner uses an agent capable of conducting a
chemical reaction to yield gas, with the gas evenly distributed in
the resin composition. In another aspect, the physically foaming
manner includes infiltrating gas into the resin composition, and
making the gas evenly distributed in the resin composition by
stirring. In another preferred embodiment of the present invention,
the plurality of pores is provided by disposing a plurality of
hollow polymeric micropheres in the elastomer. Particular examples
of the hollow micropheres are Expancel.RTM. 551DE40d42 (weight
average diameter of 30 to 50 .mu.m, produced by Akzo Nobel N.V.) or
Expancel.RTM. 551DE20d60 (weight average diameter of 15 to 25
.mu.m, produced by Akzo Nobel N.V.).
[0039] The plurality of pores according to the present invention
can be continuous pores or independent pores. The term "continuous
pores" in the present invention refers to at least two pores
connecting to each other to form a pore system similar to an ant
nest, which is beneficial to flow of the slurry, distribution of
the polishing particles and removal of polishing residues. The term
"independent pores" in the present invention refers to pores which
are independent without connecting to each other. Generally, the
independent pores have cross sections of circle shape or oval
shape, and are ball-shaped or egg-shaped pores. The independent
pores provide greater hardness and higher removal rate.
[0040] Preferably, as shown in FIG. 3, each of the pores 33 is
independent and is not connected to each other. Further, the
plurality of pores 33 is preferably ball-shaped or egg-shaped. In
another aspect, according to a preferred embodiment of the present
invention, the plurality of pores has a pore diameter of about 2
.mu.m to about 250 .mu.m, preferably about 10 .mu.m to about 150
.mu.m, and more preferably about 20 .mu.m to about 80 .mu.m.
[0041] In another embodiment of the present invention, the
polishing layer further includes a nonwoven fabric. The nonwoven
fabric can be arranged above or below the elastomer main body, or
can be immersed in the elastomer composition to form the polishing
layer.
[0042] The term "nonwoven fabric" used in the present invention
refers to a sheet, web or bat manufactured by directionally or
randomly oriented fibers, bonded by friction, and/or cohesion
and/or adhesion, excluding paper or products which are woven,
knitted, tufted stitch bonded incorporating binding yarns or
filaments, or felted by wet milling, whether or not additionally
needled. The fibers may be of natural or man-made origin. They may
be staple or continuous filaments or may be formed in situ.
Depending on the method for forming the web, the nonwoven fabric
usually includes a composite nonwoven fabric, a needle-punched
nonwoven fabric, a melt-blown nonwoven fabric, a spun bonded
nonwoven fabric, a dry-laid nonwoven fabric, a wet-laid nonwoven
fabric, a stitch-bonded nonwoven fabric, or a spun lace nonwoven
fabric. Compared with a woven fabric, a nonwoven fabric has a
better material property.
[0043] Ordinarily skilled artisans can choose suitable kinds of
fibers according to the disclosure of the specification. The term
"fibers" in the present invention refers to single fibers or
composite fibers, preferably composite fibers. Preferably, the
fibers are made of at least one material selected from the group
consisting of polyamide, terephthalamide, polyester, polymethyl
methacrylate, polyethylene terephthalate, polyacrylonitrile, and a
mixture thereof.
[0044] In an embodiment of the present invention, the plurality of
pores of the polishing pad is the void spaces between the fibers of
the nonwoven fabric. In still another embodiment of the present
invention, the plurality of pores is constructed by the elastomer
main body and the fibers jointly.
[0045] One technical feature of the present invention is to provide
the plurality of titanium dioxide nanowires, which is independent
from each other, and is dispersed evenly and randomly in the
elastomer main body. Through the addition of the plurality of
titanium dioxide nanowires, the polishing pad of the present
invention can provide improved slurry retention capacity. While not
wishing to be limited to any particular theory, it is believed that
since the titanium dioxide nanowires have extremely high
hydrophilicity (superhydrophilicity), the slurry can be
continuously adhered to the titanium dioxide nanowires during the
polishing process, thus dramatically increasing slurry retention
capacity of the polishing pad. As such, polishing efficiency can be
improved while preventing scratches on the substrate to be
polished. In another aspect, since the titanium dioxide nanowires
possess extremely high hydrophilicity, surface tension of the
elastomer composition dispersed with the titanium dioxide nanowires
can be reduced. When filling in a mold, the elastomer composition
dispersed with the titanium dioxide nanowires has a small contact
angle to a wall of the mold, and the surface of the elastomer
composition lowers to serve as nucleation sites for the pores. The
titanium dioxide nanowires are dispersed on surfaces of the pores,
thus enlarging contact area with the slurry and overcoming the
defect of varying sizes of the pores.
[0046] In a preferred embodiment of the present invention, a length
of the plurality of titanium dioxide nanowires is about 0.1 nm to
about 100 nm, preferably about 0.5 nm to about 40 nm, and more
preferably about 1 nm to about 20 nm.
[0047] In another aspect, a diameter of the plurality of titanium
dioxide nanowires is about 0.1 nm to about 50 nm, preferably about
0.5 nm to about 20 nm, and more preferably about 1 nm to about 10
nm.
[0048] Preferably, a ratio of the plurality of titanium dioxide
nanowires in the polishing layer is about 0.1% to about 20% by
weight, preferably about 0.5% to about 10% by weight, and more
preferably about 1% to about 5% by weight.
[0049] In an embodiment of the present invention, preparation of
the plurality of titanium dioxide nanowires includes a hydrothermal
method which comprises growing a lot of titanium dioxide nanowires
on a titanium dioxide substrate, sonicating the plurality of
titanium dioxide nanowires into an aqueous solution with a
supersonic apparatus, and then removing water by heating, thus
providing the plurality of titanium dioxide nanowires required in
the present invention.
[0050] In a preferred embodiment of the present invention, a
portion of the plurality of titanium dioxide nanowires is exposed
on a surface of the polishing layer.
[0051] In another preferred embodiment of the present invention, a
portion of the plurality of titanium dioxide nanowires is disposed
in the plurality of pores.
[0052] In a preferred embodiment of the present invention, the
polishing layer includes a plurality of polishing particles. The
plurality of polishing particles is evenly distributed in the
elastomer main body, as well as disposed in the plurality of pores.
Preferably, the plurality of polishing particles is made of cerium
dioxide, silicon dioxide, aluminum oxide, yttrium oxide, or ferric
oxide. In another aspect, a particle size of the plurality of
polishing particles is between about 0.01 .mu.m to about 10
.mu.m.
[0053] In a preferred embodiment of the present invention, the
polishing pad further includes a buffer layer on a surface of the
polishing layer. The term "buffer layer" as used in the present
invention refers to a thin layer located between the polishing
layer and a polishing apparatus. The buffer layer withstands the
pressure in various directions from a pressure plate and a
polishing plate during the polishing process, so as to prevent
scratches on the substrate to be polished. The buffer layer
according to the present invention includes fibers which can be the
same as those fibers of the nonwoven fabric described above, and
are not repeated again.
[0054] In a preferred embodiment of the present invention, the
polishing pad further includes a binder layer for binding the
polishing layer and the buffer layer together. Preferably, a
material of the binder layer is selected from a group consisting of
pressure-sensitive adhesive, one-part adhesive, two-part adhesive,
polyol curing-type PU paste, acrylic resin, and epoxy resin. The
pressure-sensitive adhesive generally includes a supporting film
which can be, for instance, a polyester film. A fluidic adhesive
agent is coated on upper and lower sides of the supporting film.
The one-part adhesive refers to an adhesive agent which utilizes an
elastomer with high molecular weight for providing adhesion
function, preferably includes polyurethane. The one-part adhesive
includes oil-modified paste and moisture-curing paste. The
oil-modified paste is formed by reacting natural oil-modified or
diglyceride-modified polyols with toluene diisocyanate (TDI). The
moisture-curing paste includes hydroxyl-containing polyesters and
polyethers, with excess NCO groups (NCO/OH>1) reacting with
hydroxyl groups of toluene diisocyanate, diphenylmethane
diisocyanate (MDI), hexamethylene diisocyanate (HMDI), etc., to
form isocyanate-terminated prepolymers. Such isocyanate groups can
react with moisture in the air to produce amines, which undergoes
further reactions to form urea linkage and biuret, thus forming a
cured film. The two-part adhesive refers to an adhesive agent
including two components which react or crosslink with each other
to provide adhesion function; preferably includes an elastomer and
polyisocyanate. The two-part adhesive may be of catalyst-curing
type, which is cured by reacting a mono-diglyceride mixture
transesterified by polyethylene glycol, polypropylene glycol or
polyol with a catalyst, such as tertiary amines or metal salts. The
polyolcuring-type PU paste may be formed by reacting isocyanate
prepolymers and a hydroxyl group of polyol-esters or polyethers or
polyols, such as hydroxyl-containing acrylic resins. The acrylic
resin may be cold curing type or dry-heat curing type. The cold
curing-type acrylic resin, which can be cured under room
temperature, is essentially composed of acrylic resin monomers. The
heat-dry curing-type acrylic resin includes acrylic resin polymers
as the basic structure, with active reacting groups introduced
therein. When heated, said resin alone or with a resin containing
reacting groups and crosslinking agent undergo a reaction to form a
3D network structure. The epoxy resin can form 3D network structure
with the addition of the crosslinking agent.
[0055] In an embodiment of the present invention, the polishing
layer and the buffer layer are produced separately, and then bound
together by the binder layer. Means for binding the polishing layer
with the buffer layer can be varied according to the forms of the
binder layer. The binder layer for binding the polishing layer and
the buffer layer is preferably applied on a surface of the buffer
layer or the polishing layer by coating, transferring, printing or
scraping, more preferably by coating on a surface of the buffer
layer or the polishing layer.
[0056] In another preferred embodiment of the present invention,
the polishing layer further includes a polishing surface, and the
polishing surface includes a groove. A proper processing for
forming the groove on the polishing surface may be chosen by
ordinarily skilled artisans based on the disclosure of the
specification. For instance, laser processing can be used. The
groove assists slurry flow during the polishing process.
Preferably, the ratio of the groove interval and the groove width
is from about 1 to about 0.05.
[0057] In another preferred embodiment of the present invention,
the polishing pad further includes an adhesive layer on a surface
of the polishing layer, which is adapted for fixing the polishing
pad on a polishing plate. A material of the adhesive layer can be
the same as that of the binder layer, thus is not repeated
again.
[0058] The present invention also provides a polishing apparatus,
including: [0059] a polishing plate; [0060] a substrate; [0061] a
polishing pad adhered on the polishing plate for polishing the
substrate; and [0062] slurry contacting with the substrate for
polishing.
[0063] Preferably, the polishing apparatus further includes: [0064]
a pressure plate positioned opposite to the polishing plate; and
[0065] a mounting sheet adhered on the pressure plate for carring
and mounting the substrate.
[0066] FIG. 4 shows a schematic view of a polishing apparatus
according to the polishing pad of the invention. The polishing
apparatus 4 includes a pressure plate 41, a mounting sheet 42, a
substrate 43, a polishing plate 44, a polishing pad 45 and slurry
46. The pressure plate 41 is positioned opposite to the polishing
plate 44. The mounting sheet 42 is adhered to the pressure plate 41
through a backside adhesive (not shown) and is used for carrying
and mounting the substrate 43. The polishing pad 45 is mounted on
the polishing plate 44 and faces the pressure plate 41 for
polishing the substrate 43.
[0067] The operation manner of the polishing apparatus 4 is as
follows. First, the substrate 43 is mounted on the mounting sheet
42, and then both the pressure plate 41 and the polishing plate 44
are rotated and the pressure plate 41 is simultaneously moved
toward the polishing plate 44, such that the polishing pad 45
contacts the surface of the substrate 43. Accordingly, the
substrate 43 can be polished by the polishing pad 45 with the
continuously supplemented slurry 46.
[0068] The present invention further provides a method for
manufacturing the polishing pad according to claim 1, comprising:
[0069] (a) providing an elastomer composition; [0070] (b) providing
the plurality of titanium dioxide nanowires; [0071] (c) dispersing
the titanium dioxide nanowires of the step (b) evenly and randomly
in the elastomer composition of the step (a); [0072] (d) providing
the polishing layer by curing the elastomer composition to form the
elastomer main body.
[0073] In a preferred embodiment of the present invention,
definition of the elastomer composition is the same as described
above, thus is not repeated again.
[0074] In an embodiment of the present invention, the method
further includes coating the elastomer composition randomly
dispersed with the plurality of titanium dioxide nanowires of the
step (c) on a carrier before the step (d).
[0075] The term "carrier" in the present invention refers to an
element which allows the elastomer composition to be formed thereon
and to be easily removed therefrom after cured. Preferably, the
carrier is a sheet; in another aspect, the carrier is a release
liner. The term "release liner" in the present invention refers to
a material which does not react with the elastomer composition
during the polishing pad manufacturing process, and the cured
elastomer composition can be easily removed from such material.
Preferably, the release liner is "a film with low permeability."
The term "film with low permeability" in the present invention
refers to a film or a thin membrane which substantially prevents
the elastomer composition on an upper surface thereof from
permeating to a lower surface thereof. In a preferred embodiment of
the invention, the film with low permeability can be formed on a
base material, such as paper. Preferably, the carrier includes a
polyethylene glycol terephthalate film, a polypropylene film, a
polycarbonate film, a polyethylene film, a polyethylene
terephthalate film, releasing paper or a releasing fabric.
Additionally, the preferable polypropylene is oriented
polypropylene.
[0076] Preferably, the carrier is continuously provided, such as a
release liner roll. The release liner roll can be used in a
roll-to-roll manner Comparing to the conventional manufacture
process related to molding or casting a single polishing pad, the
method according to the invention improves batch uniformity.
[0077] In an embodiment of the present invention, the method
further includes filling the elastomer composition randomly
dispersed with the plurality of titanium dioxide nanowires of the
step (c) in a cavity of a mold before the step (d). Particular
means of the method can be readily performed by ordinarily skilled
artisans. For instance, the plurality of titanium dioxide nanowires
can be mixed or stirred with the components of the elastomer
composition, so as to prepare the elastomer composition and
disperse the titanium dioxide nanowires evenly and randomly in the
elastomer composition at the same time.
[0078] In an embodiment of the present invention, the method
further includes immersing a nonwoven fabric in the elastomer
composition randomly dispersed with the plurality of titanium
dioxide nanowires of the step (c) before the step (d), which is
performed by a common method for immersing a fabric in an elastomer
liquid. The immersing conditions can be readily understood by
ordinarily skilled artisans.
[0079] According to the method in the present invention, the step
(d) cures the elastomer composition of the step (c). Particular
means for the curing step can be determined ordinarily skilled
artisans based on the types of the resin and the optional
crosslinking agent. In a preferred embodiment of the present
invention, the curing step includes curing the elastomer
composition at about 60.degree. C. to about 130.degree. C. after
the elastomer composition is dried under a high temperature.
[0080] Preferably, the method according to the present invention
further includes a slicing step of cutting the elastomer cured in
the mold into slices as the polishing pads. Particular means for
the slicing step can be readily understood by ordinarily skilled
artisans.
[0081] In a preferred embodiment of the present invention, the
method further includes a step of removing the carrier. Preferably,
the step of removing the carrier can be performed right after the
manufacture process, removing the polishing pad from the
manufacturing equipment. Alternatively, the carrier-removing step
can be performed just before the polishing process, removing the
carrier from the polishing pad. Particular means for the
carrier-removing step can be choosen based on the type of the
carrier, such as a teering process.
[0082] While embodiments of the present invention have been
illustrated and described, various modifications and improvements
can be made by persons skilled in the art. It is intended that the
present invention is not limited to the particular forms as
illustrated, and that all modifications not departing from the
spirit and scope of the present invention are within the scope as
defined in the following claims.
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