U.S. patent application number 12/493491 was filed with the patent office on 2010-04-22 for polishing pad having abrasive grains and method for making the same.
This patent application is currently assigned to BESTAC ADVANCED MATERIAL CO., LTD.. Invention is credited to Chung-Chih Feng, Yung-Chang Hung, Chih-Yi Lin, Kun-Cheng Tsai, I-Peng Yao.
Application Number | 20100099343 12/493491 |
Document ID | / |
Family ID | 42109056 |
Filed Date | 2010-04-22 |
United States Patent
Application |
20100099343 |
Kind Code |
A1 |
Feng; Chung-Chih ; et
al. |
April 22, 2010 |
POLISHING PAD HAVING ABRASIVE GRAINS AND METHOD FOR MAKING THE
SAME
Abstract
The present invention relates to a polishing pad having abrasive
grains and a method for making the same. The polishing pad having
abrasive grains includes a plurality of fibers, a plurality of
abrasive grains and a high polymer. The fibers intersect each other
to form a fiber matrix. The abrasive grains are attached to the
fibers. The high polymer covers the fibers and the abrasive grains.
The abrasive grains will not easily scratch a surface of a
workpiece to be polished due to the flexibility of the fibers.
Inventors: |
Feng; Chung-Chih;
(Kaohsiung, TW) ; Yao; I-Peng; (Kaohsiung, TW)
; Hung; Yung-Chang; (Kaohsiung, TW) ; Tsai;
Kun-Cheng; (Kaohsiung, TW) ; Lin; Chih-Yi;
(Kaohsiung, TW) |
Correspondence
Address: |
WPAT, PC;INTELLECTUAL PROPERTY ATTORNEYS
2030 MAIN STREET, SUITE 1300
IRVINE
CA
92614
US
|
Assignee: |
BESTAC ADVANCED MATERIAL CO.,
LTD.
Taoyuan County
TW
|
Family ID: |
42109056 |
Appl. No.: |
12/493491 |
Filed: |
June 29, 2009 |
Current U.S.
Class: |
451/532 ;
51/295 |
Current CPC
Class: |
B24B 37/245
20130101 |
Class at
Publication: |
451/532 ;
51/295 |
International
Class: |
B24D 11/00 20060101
B24D011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 20, 2008 |
TW |
097140109 |
Claims
1. A polishing pad having abrasive grains, comprising: a plurality
of fibers, intersecting each other to form a fiber matrix; a
plurality of abrasive grains, attached to the fibers; and a high
polymer, covering the fibers and the abrasive grains.
2. The polishing pad according to claim 1, further comprising a
bottom layer, wherein a second surface of the high polymer is
disposed on the bottom layer.
3. The polishing pad according to claim 1, wherein the fiber matrix
is a non-woven fabric.
4. The polishing pad according to claim 1, wherein the fibers are
solid or hollow and the fibers are made of a material selected from
a group consisting of a polyamide resin, polyethylene terephthalate
(PET), polyester resin, nylon, polypropylene (PP), acrylic resin
and polyacrylonitrile resin.
5. The polishing pad according to claim 1, wherein the abrasive
grains are disposed inside the fibers, and a portion of the
abrasive grains are exposed to surfaces of the fibers.
6. The polishing pad according to claim 1, wherein the abrasive
grains are disposed on the surfaces of the fibers.
7. The polishing pad according to claim 1, wherein the abrasive
grains are made of a material selected from a group consisting of
SiO.sub.2, CeO.sub.2, Al.sub.2O.sub.3, oxides of transition metals
and oxides of Group IIA metals.
8. The polishing pad according to claim 1, wherein the high polymer
has a first surface and a second surface, and a portion of the
fibers and a portion of the abrasive grains are exposed to the
first surface.
9. The polishing pad according to claim 1, wherein the high polymer
is made of a material selected from a group consisting of a
polyamide resin, polycarbonate, polymethacrylic resin, epoxy resin,
phenol resin, polyurethane resin, vinylbenzene resin and acrylic
resin.
10. The polishing pad according to claim 1, wherein the high
polymer is an intercommunicated porous high-polymeric elastomer
resin.
11. A method for making a polishing pad having abrasive grains,
comprising: (a) providing a fiber matrix, wherein the fiber matrix
has a plurality of fibers and a plurality of abrasive grains, the
fibers intersect each other, and the abrasive grains are attached
to the fibers; (b) immersing the fiber matrix in a high-polymer
solution; and (c) performing a curing step, such that the fiber
matrix is covered with a high polymer.
12. The method according to claim 11, wherein Step (a) comprises:
(a1) providing a fiber raw material, and performing a spinning
step, such that the fiber raw material forms a plurality of fibers;
(a2) providing a plurality of abrasive grains, and attaching the
abrasive grains to surfaces of the fibers; and (a3) performing a
drawing step, such that the fibers form the fiber matrix.
13. The method according to claim 12, wherein in Step (a1), the
spinning step is melt spinning, dry spinning or wet spinning.
14. The method according to claim 11, wherein Step (a) comprises:
(a1) providing a fiber raw material and a plurality of abrasive
grains, and adding the abrasive grains into the fiber raw material;
(a2) performing a spinning step, such that the fiber raw material
forms a plurality of fibers, wherein a portion of the abrasive
grains are disposed inside the fibers, and a portion of the
abrasive grains are exposed to the surfaces of the fibers; and (a3)
performing a drawing step, such that the fibers form the fiber
matrix.
15. The method according to claim 14, wherein in Step (a2), the
spinning step is melt spinning, dry spinning or wet spinning.
16. The method according to claim 11, wherein in Step (a), the
fibers are solid or hollow.
17. The method according to claim 11, wherein in Step (a), the
abrasive grains are made of a material selected from a group
consisting of SiO.sub.2 CeO.sub.2, Al.sub.2O.sub.3, oxides of
transition metals and oxides of Group IIA metals.
18. The method according to claim 11, wherein in Step (a), the
fiber matrix is a non-woven fabric, and is formed by chemical
bonding, thermal bonding, mechanical bonding, dry carding, direct
web-forming or wet web-forming.
19. The method according to claim 11, wherein Step (c) further
comprises a step of removing a portion of the high polymer, such
that a portion of the fibers and a portion of the abrasive grains
are exposed to a first surface of the high polymer.
20. The method according to claim 11, wherein after Step (c), the
method further comprises a step of forming a bottom layer on a
second surface of the high polymer.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a polishing pad and a
method for making the same, in particular, to a polishing pad
having abrasive grains and a method for making the same.
[0003] 2. Description of the Related Art
[0004] In a conventional polishing method, a slurry is used
together with a polishing pad. The slurry has a plurality of
abrasive grains, which are used to polish a surface of a workpiece
to be polished. The polishing pad has a plurality of pores, and the
pores are communicated with each other, such that the slurry is
uniformly dispersed over a surface of the polishing pad, so as to
improve the polishing capability.
[0005] The conventional polishing method has the following
disadvantages. During the polishing process, when the slurry flows
through the pores, the abrasive grains of the slurry may easily
block the pores, thus degrading the polishing capability. Then, a
dresser needs to be used to dress the blocked pores and recover the
polishing capability of the polishing pad. However, the addition of
such a step in the original process will increase cost and lower
efficiency.
[0006] In another conventional polishing method, a polishing pad
having abrasive grains is used. FIG. 1 shows a schematic view of a
conventional polishing pad having abrasive grains disclosed in
Taiwan Patent Publication No. I233384. The polishing pad 1 having
abrasive grains includes a bottom layer 11 and a polishing layer
12. The polishing layer 12 is disposed on the bottom layer 11, and
has a resin 121 and a plurality of abrasive grains 122. The resin
121 covers the abrasive grains 122, and has a polishing surface
1211. A portion of the abrasive grains 122 is exposed to the
polishing surface 1211 of the resin 121.
[0007] The conventional polishing pad 1 with abrasive grains has
the following disadvantages. The polishing pad 1 having abrasive
grains utilizes the resin 121 to fix the abrasive grains 122, so
that during the polishing process, the abrasive grains 122 are
fixed at the same position, abrade the workpiece to be polished
with repetitive stress in a single direction, and thus easily
scratch the workpiece to be polished. Meanwhile, as the resin 121
is gradually worn, the area of the abrasive grains 122 fixed within
the resin 121 that are exposed to the polishing surface 1211
becomes larger, and the problem of scratching grows worse.
[0008] Therefore, it is necessary to provide a polishing pad having
abrasive grains and a method for making the same, so as to solve
the above problems.
SUMMARY OF THE INVENTION
[0009] The present invention is directed to a polishing pad having
abrasive grains. The polishing pad comprises a plurality of fibers,
a plurality of abrasive grains and a high polymer. The fibers
intersect each other to form a fiber matrix. The abrasive grains
are attached to the fibers. The high polymer covers the fibers and
the abrasive grains.
[0010] The present invention is further directed to a method for
making a polishing pad having abrasive grains. The method comprises
the steps of: (a) providing a fiber matrix, in which the fiber
matrix has a plurality of fibers and a plurality of abrasive
grains, the fibers intersect each other, and the abrasive grains
are attached to the fibers; (b) immersing the fiber matrix in a
high-polymer solution; and (c) performing a curing step, such that
the fiber matrix is covered with a high polymer.
[0011] Thereby, the abrasive grains may not easily scratch a
surface of a workpiece to be polished due to the flexibility of the
fibers, and the polishing pad has a desirable polishing capability
due to the assistance of an acid or alkali slurry containing no
abrasive grains or an electrolytic solution containing an
electrolyte, thus avoiding the problem in the prior art that the
abrasive grains of the slurry block the pores of the polishing pad.
Moreover, after the polishing pad is used in the polishing process,
only a small number of abrasive grains are left on the surface of
the workpiece to be polished, which can be easily washed away by a
simple rinsing procedure, and the wastewater may also be easily
treated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic view of a polishing pad having
abrasive grains in the prior art;
[0013] FIG. 2 is a schematic view of a polishing pad having
abrasive grains according to a first embodiment of the present
invention;
[0014] FIG. 3 is a schematic cross-sectional view of fibers of the
polishing pad having abrasive grains according to the first
embodiment of the present invention, in which the fibers are
solid;
[0015] FIG. 4 is a schematic cross-sectional view of fibers of the
polishing pad having abrasive grains according to the first
embodiment of the present invention, in which the fibers are
hollow;
[0016] FIG. 5 is a flow chart of a method for making the polishing
pad having abrasive grains according to the first embodiment of the
present invention;
[0017] FIG. 6 is a schematic view of a polishing pad having
abrasive grains according to a second embodiment of the present
invention;
[0018] FIG. 7 is a schematic cross-sectional view of fibers of the
polishing pad having abrasive grains according to the second
embodiment of the present invention, in which the fibers are
solid;
[0019] FIG. 8 is a schematic cross-sectional view of fibers of the
polishing pad having abrasive grains according to the second
embodiment of the present invention, in which the fibers are
hollow; and
[0020] FIG. 9 is a flow chart of a method for making the polishing
pad having abrasive grains according to the second embodiment of
the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] FIG. 2 shows a schematic view of a polishing pad having
abrasive grains according to a first embodiment of the present
invention. The polishing pad 2 having abrasive grains comprises a
plurality of fibers 21, a plurality of abrasive grains 22 and a
high polymer 23. In other applications, the polishing pad 2 further
comprises a bottom layer, which may be a glue layer or another
composite layer.
[0022] The abrasive grains 22 are attached to the fibers 21, and
the fibers 21 intersect each other to form a fiber matrix 24. In
this embodiment, the fibers 21 are solid, and the abrasive grains
22 are disposed on surfaces of the fibers 21 (as shown in FIG. 3).
In other applications, the fibers 21 may be hollow, and the
abrasive grains 22 are disposed on surfaces of the fibers 21 (as
shown in FIG. 4).
[0023] Preferably, the fibers 21 have a size of 0.001 to 6 denier.
Preferably, the fibers 21 are made of a material selected from a
group consisting of a polyamide resin, polyethylene terephthalate
(PET), polyester resin, nylon, polypropylene (PP), acrylic resin
and polyacrylonitrile resin. In this embodiment, the fiber matrix
24 is a non-woven fabric. Preferably, the fiber matrix 24 is formed
by chemical bonding, thermal bonding, mechanical bonding, dry
carding, direct web-forming or wet web-forming. In this embodiment,
the abrasive grains 22 have an average diameter of 0.01 to 100
.mu.m, and are made of a material selected from a group consisting
of SiO.sub.2 CeO.sub.2, Al.sub.2O.sub.3, oxides of transition
metals and oxides of Group IIA metals.
[0024] The high polymer 23 covers the fibers 21 and the abrasive
grains 22, and has a first surface 231 and a second surface 232.
Preferably, a portion of the fibers 21 and a portion of the
abrasive grains 22 are exposed to the first surface 231. The first
surface 231 is a polishing surface. In other applications, the high
polymer 23 completely covers the fibers 21 and the abrasive grains
22. After the polishing process has been performed for a period of
time, and a portion of the high polymer 23 on the first surface 231
(polishing surface) is removed, a portion of the fibers 21 and a
portion of the abrasive grains 22 are exposed to the first surface
231. Alternatively, a portion of the high polymer 23 on the first
surface 231 is removed (for example, dressed or abraded) in advance
before the polishing process is performed, such that a portion of
the fibers 21 and a portion of the abrasive grains 22 are exposed
to the first surface 231, and then the polishing process is
performed. In this embodiment, the high polymer 23 is an
intercommunicated porous high polymeric elastomer resin.
Preferably, the high polymer 23 is made of a material selected from
a group consisting of a polyamide resin, polycarbonate,
polymethacrylic resin, epoxy resin, phenol resin, polyurethane
resin, vinylbenzene resin and acrylic resin. In other applications,
the second surface 232 of the high polymer 23 is disposed on the
bottom layer.
[0025] FIG. 5 shows a flow chart of a method for making the
polishing pad having abrasive grains according to the first
embodiment of the present invention. Referring to FIGS. 2 and 5,
first, in Step S51, a fiber raw material (not shown) is provided,
and a spinning step is performed, such that the fiber raw material
forms a plurality of fibers 21. Preferably, the spinning step is
melt spinning, dry spinning or wet spinning. In this embodiment,
the fibers 21 are solid (as shown in FIG. 3). In other
applications, the fibers 21 may be hollow (as shown in FIG. 4).
Preferably, the fibers 21 have a size of 0.001 to 6 denier.
Preferably, the fibers 21 are made of a material selected from a
group consisting of a polyamide resin, PET, polyester resin, nylon,
PP, acrylic resin and polyacrylonitrile resin.
[0026] Next, in Step S52, a plurality of abrasive grains 22 is
provided, and then attached to surfaces of the fibers 21 (as shown
in FIGS. 3 and 4). In other applications, each of the abrasive
grains 22 is exposed to the surfaces of the fibers 21; that is,
each of the abrasive grains 22 is partially disposed inside the
fibers 21 and partially exposed to the surfaces of the fibers 21.
Alternatively, a portion of the abrasive grains 22 are disposed
inside the fibers 21, and a portion of the abrasive grains 22 are
exposed to the surfaces of the fibers 21 (as shown in FIGS. 7 and
8). Preferably, the abrasive grains 22 are made of a material
selected from a group consisting of SiO.sub.2 CeO.sub.2,
Al.sub.2O.sub.3, oxides of transition metals and oxides of Group
IIA metals.
[0027] Afterward, in Step S53, a drawing step is performed, such
that the fibers 21 form a fiber matrix 24. In this embodiment, the
fiber matrix 24 is a non-woven fabric. Preferably, the fiber matrix
24 is formed by chemical bonding, thermal bonding, mechanical
bonding, dry carding, direct web-forming or wet web-forming. Then,
in Step S54, the fiber matrix 24 is immersed in a high-polymer
solution (not shown).
[0028] Finally, in Step S55, a curing step is performed, such that
the fiber matrix 24 is covered with a high polymer 23. The high
polymer 23 has a first surface 231 and a second surface 232.
Preferably, a portion of the fibers 21 and a portion of the
abrasive grains 22 are exposed to the first surface 231 of the high
polymer 23. In other applications, in Step S55, the high polymer 23
completely covers the fiber matrix 24. Alternatively, in Step S55,
the high polymer 23 completely covers the fiber matrix 24, and in
Step S55, the method further comprises a step of removing (for
example, dressing or abrading) a portion of the high polymer 23,
such that a portion of the fibers 21 and a portion of the abrasive
grains 22 are exposed to the first surface 231 of the high polymer
23. Preferably, after Step S55, the method further comprises a step
of forming a bottom layer on the second surface 232 of the high
polymer 23, in which the bottom layer is a glue layer.
[0029] FIG. 6 shows a schematic view of a polishing pad having
abrasive grains according to a second embodiment of the present
invention. The polishing pad 3 of this embodiment is substantially
the same as the polishing pad 2 (FIG. 2) of the first embodiment.
This embodiment is different from the first embodiment in that the
abrasive grains 32 are disposed inside the fibers 31. In this
embodiment, the fibers 31 are solid, the abrasive grains 32 are
disposed inside the fibers 31, and a portion of the abrasive grains
32 are exposed to surfaces of the fibers 31 (as shown in FIG. 7).
However, in other applications, the fibers 31 may be hollow (as
shown in FIG. 8).
[0030] FIG. 9 shows a flow chart of a method for making the
polishing pad having abrasive grains according to the second
embodiment of the present invention. Referring to FIGS. 6 and 9,
first, in Step S91, a fiber raw material (not shown) and a
plurality of abrasive grains 32 are provided, and the abrasive
grains 32 are added into the fiber raw material. Preferably, the
abrasive grains 32 are made of a material selected from a group
consisting of SiO.sub.2 CeO.sub.2, Al.sub.2O.sub.3, oxides of
transition metals and oxides of Group IIA metals.
[0031] Next, in Step S92, a spinning step is performed, such that
the fiber raw material forms a plurality of fibers 31, in which a
portion of the abrasive grains 32 are disposed inside the fibers
31, and a portion of the abrasive grains 32 are exposed to the
surfaces of the fibers 31 (as shown in FIGS. 7 and 8). Preferably,
the spinning step is melt spinning, dry spinning or wet spinning.
In this embodiment, the fibers 31 are solid (as shown in FIG. 7).
In other applications, the fibers 31 may be hollow (as shown in
FIG. 8). Preferably, the fibers 31 have a size of 0.001 to 6
denier. Preferably, the fibers 31 are made of a material selected
from a group consisting of a polyamide resin, PET, polyester resin,
nylon, PP, acrylic resin and polyacrylonitrile resin.
[0032] Afterward, in Step S93, a drawing step is performed, such
that the fibers 31 form a fiber matrix 34. In this embodiment, the
fiber matrix 34 is a non-woven fabric. Preferably, the fiber matrix
34 is formed by chemical bonding, thermal bonding, mechanical
bonding, dry carding, direct web-forming or wet web-forming. Then,
in Step S94, the fiber matrix 34 is immersed in a high-polymer
solution (not shown).
[0033] Finally, in Step S95, a curing step is performed, such that
the fiber matrix 34 is covered with a high polymer 33. The high
polymer 33 has a first surface 331 and a second surface 332.
Preferably, a portion of the fibers 31 and a portion of the
abrasive grains 32 are exposed to the first surface 331 of the high
polymer 33. In other applications, in Step S95, the high polymer 33
completely covers the fiber matrix 34. Alternatively, in Step S95,
the high polymer 33 completely covers the fiber matrix 34, and in
Step S95, the method further comprises a step of removing (for
example, dressing or abrading) a portion of the high polymer 33,
such that a portion of the fibers 31 and a portion of the abrasive
grains 32 are exposed to the first surface 331 of the high polymer
33. The first surface 331 is a polishing surface.
[0034] The present invention has the following advantages. During
the polishing process, due to the flexibility of the fibers 21, 31,
the fibers 21, 31 that are exposed to the first surface 231, 331
swing as the slurry flows under the effect of a stress between the
polishing pad 2, 3 and the workpiece to be polished, such that the
abrasive grains 22, 32 attached thereto also move accordingly
instead of being fixed at the same position. Thereby, the abrasive
grains 22, 32 may not easily scratch the surface of the workpiece
to be polished. In addition, the polishing pad 2, 3 achieves a
desirable polishing capability with the assistance of an acid or
alkali slurry containing no abrasive grains or an electrolytic
solution containing an electrolyte, thus avoiding the problem in
the prior art that the abrasive grains of the slurry block the
pores of the polishing pad. Moreover, after the polishing pad 2, 3
is used in the polishing process, only a small number of abrasive
grains 22, 32 are left on the surface of the workpiece to be
polished, which can be easily washed away by a simple rinsing
procedure, and the wastewater may also be easily treated.
[0035] Examples are given below to illustrate the present
invention, and the present invention is not limited thereto.
Example
[0036] The method of this example corresponds to that of the second
embodiment. Referring to FIG. 6, first, a fiber raw material and a
plurality of abrasive grains 32 are provided, and the abrasive
grains 32 are added into the fiber raw material. The fiber raw
material contains 57 wt % of PET and 40 wt % of polyethylene (PE),
and the abrasive grains 32 are 3 wt % of SiO.sub.2.
[0037] Next, a spinning step is performed, such that the fiber raw
material forms a plurality of fibers 31. The fibers 31 are solid, a
portion of the abrasive grains 32 are disposed inside the fibers
31, and a portion of the abrasive grains 32 are exposed to the
surfaces of the fibers 31 (as shown in FIG. 7). The spinning step
is melt spinning. In this step, the fiber raw material first passes
through an extruder and is melted at 288.degree. C., spun from a
spinneret, and then cooled at 22.degree. C. The spinning speed is
550 m/min. Afilament is obtained, which is then cut into short
fibers to form the fibers 31.
[0038] Afterward, a drawing step is performed, such that the fibers
31 form a fiber matrix 34. The fiber matrix 34 is a non-woven
fabric. Then, the fiber matrix 34 is immersed in a high-polymer
solution (not shown). The high-polymer solution is made of a
material selected from a group consisting of a polyamide resin,
polycarbonate, polymethacrylic resin, epoxy resin, phenol resin,
polyurethane resin, vinylbenzene resin and acrylic resin.
[0039] Finally, a curing step is performed. First, the fiber matrix
34 immersed in the high-polymer solution is placed in a 22%
dimethylformamide (DMF) coagulation bath for coagulation, then
placed in a rinsing bath to wash away the DMF, and dried at
150.degree. C., so as to obtain a polishing pad 3 having the
abrasive grains 32. Thereby, the fiber matrix 34 is covered with a
high polymer 33. The high polymer 33 has a first surface 331 and a
second surface 332. A portion of the fibers 31 and a portion of the
abrasive grains 32 are exposed to the first surface 331 of the high
polymer 33.
[0040] While several embodiments of the present invention have been
illustrated and described, various modifications and improvements
can be made by those skilled in the art. The embodiments of the
present invention are therefore described in an illustrative but
not restrictive sense. It is intended that the present invention
should not be limited to the particular forms as illustrated, and
that all modifications which maintain the spirit and scope of the
present invention are within the scope defined in the appended
claims.
* * * * *