U.S. patent application number 12/536164 was filed with the patent office on 2010-06-17 for polishing pad having insulation layer 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, Wei-Te Liu, Chun-Ta Wang, I-Peng Yao.
Application Number | 20100146863 12/536164 |
Document ID | / |
Family ID | 42238906 |
Filed Date | 2010-06-17 |
United States Patent
Application |
20100146863 |
Kind Code |
A1 |
Feng; Chung-Chih ; et
al. |
June 17, 2010 |
POLISHING PAD HAVING INSULATION LAYER AND METHOD FOR MAKING THE
SAME
Abstract
The present invention relates to a polishing pad having an
insulation layer and a method for making the same. The polishing
pad includes a bottom layer, an insulation layer, and an abrasive
layer. The bottom layer includes a fabric layer wrapped in a high
polymer. The insulation layer is disposed on the bottom layer. The
abrasive layer is disposed on the insulation layer. The abrasive
layer is a high polymeric elastomer and has a plurality of
columnar-like cells. The insulation layer can prevent the slurry
from infiltrating into the bottom layer during the polishing
processs to improve the polishing effect and quality.
Inventors: |
Feng; Chung-Chih;
(Kaohsiung, TW) ; Yao; I-Peng; (Kaohsiung, TW)
; Hung; Yung-Chang; (Kaohsiung, TW) ; Wang;
Chun-Ta; (Kaohsiung, TW) ; Liu; Wei-Te;
(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: |
42238906 |
Appl. No.: |
12/536164 |
Filed: |
August 5, 2009 |
Current U.S.
Class: |
51/296 ;
51/298 |
Current CPC
Class: |
B24B 37/22 20130101 |
Class at
Publication: |
51/296 ;
51/298 |
International
Class: |
B24D 11/00 20060101
B24D011/00; B24D 3/00 20060101 B24D003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 15, 2008 |
TW |
097148792 |
Claims
1. A polishing pad, comprising: a bottom layer, comprising a fabric
layer wrapped in a high polymer; an insulation layer, disposed on
the bottom layer; and an abrasive layer, disposed on the insulation
layer, wherein the abrasive layer is a high polymeric elastomer and
has a plurality of columnar-like cells.
2. The polishing pad according to claim 1, wherein the fabric layer
is a non-woven fabric.
3. The polishing pad according to claim 1, wherein the fabric layer
is made of polypropylene (PP), polyethylene terephthalate (PET),
nylon, or a mixer thereof.
4. The polishing pad according to claim 1, wherein the high polymer
is made of polyurethanes (PU), PP, PET, a high-polymer resin, or a
mixer thereof.
5. The polishing pad according to claim 1, wherein the bottom layer
has a surface, a fiber portion of the fabric layer is exposed to
the surface, and the insulation layer further enwraps the exposed
fiber portion.
6. The polishing pad according to claim 1, wherein the insulation
layer is coated on the bottom layer.
7. The polishing pad according to claim 1, wherein the insulation
layer is made of PU, PP, PET, a high-polymer resin, a thin metal
layer, or a metal powder.
8. The polishing pad according to claim 1, wherein the abrasive
layer is coated on the insulation layer, and is made of PU, PP,
PET, a high-polymer resin, or a mixer thereof.
9. The polishing pad according to claim 1, wherein the
columnar-like cells are distributed over a thickness that is at
least one half of the overall thickness of the abrasive layer, and
the depth of the columnar-like cells is greater than one half of
the overall thickness of the abrasive layer.
10. The polishing pad according to claim 1, wherein the polishing
pad has a compression ratio of 5% to 50%.
11. The polishing pad according to claim 1, wherein the polishing
pad has a recovery ratio greater than 80%.
12. The polishing pad according to claim 1, wherein the fabric
layer is made of PET, the high polymer is made of PU, the
insulation layer comprises PU and methyl ethyl ketone (MEK), and
the abrasive layer is made of PU.
13. A method for making a polishing pad, comprising: (a) providing
a bottom layer, wherein the bottom layer comprises a fabric layer
wrapped in a high polymer and has a surface; (b) forming an
insulation layer on the surface of the bottom layer; (c) forming a
high polymeric elastomer on the insulation layer; (d) curing the
high polymeric elastomer to form an abrasive layer, wherein the
abrasive layer has a plurality of columnar-like cells; and (e)
abrading a surface of the abrasive layer, such that the abrasive
layer has a plurality of surface openings.
14. The method according to claim 13, wherein Step (a) comprises:
(a1) providing a fabric layer; (a2) immersing the fabric layer in a
high-polymer solution, such that the high-polymer solution enwraps
the fabric layer; and (a3) curing the high-polymer solution to form
the bottom layer.
15. The method according to claim 13, wherein a fiber portion of
the fabric layer in Step (a) is exposed to the surface of the
bottom layer and the insulation layer in Step (b) further enwraps
the exposed fiber portion.
16. The method according to claim 13, wherein in Step (b), the
insulation layer is formed on the bottom layer by coating,
roll-printing, or transferring.
17. The method according to claim 13, wherein in Step (c), the high
polymeric elastomer is formed on the insulation layer by coating,
roll-printing, or transferring.
18. The method according to claim 13, wherein in Step (d), the
bottom layer, the insulation layer, and the high polymeric
elastomer are immersed in a curing solution, so as to cure the high
polymeric elastomer to form an abrasive layer, and generate the
columnar-like cells in the abrasive layer.
19. The method according to claim 18, wherein the curing solution
comprises dimethylformamide (DMF) and water.
20. The method according to claim 13, wherein in Step (e), the
surface of the abrasive layer is abraded, and scraps are removed by
vacuum suction.
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, and particularly, to a polishing pad
having an insulation layer and a method for making the same.
[0003] 2. Description of the Related Art
[0004] Polishing generally refers to abrading a rough surface in a
chemical mechanical polishing (CMP) process, in which a slurry
containing abrasive grains is uniformly dispersed on a surface of a
polishing pad, and meanwhile a workpiece to be polished is pressed
against the polishing pad and then rubbed repeatedly and regularly.
The workpiece to be polished is an object such as a semiconductor,
a storage medium substrate, an integrated circuit (IC), an LCD flat
glass, an optical glass, or a photoelectric panel.
[0005] In the prior art, a polishing pad is mostly fabricated by
multi-layer adhesion. For example, an abrasive layer is adhered to
a bottom layer with a glue (referring to a multi-layer polishing
pad disclosed in Taiwan Patent Publication No. M269996); or an
abrasive layer formed by a plurality of thin layers adhered
together is further adhered to a bottom layer with a glue
(referring to a multi-layer polishing pad for CMP disclosed in
Taiwan Patent Publication No. 200513348).
[0006] After the above-mentioned polishing pads in the prior art
are immersed in the slurry, a stress may easily occur as the
abrasive layer and the bottom layer that are made of different
materials and the glue used for adhesion have different compression
ratios. In addition, the glue's adhesive strength may be gradually
degraded if immersed in the slurry for a long time, resulting in
poor flatness of the surface of the polishing pad. Moreover, during
the polishing process, when a polishing machine applies a force to
an object to be polished, a protruding portion of the surface of
the polishing pad may severely abrade or scratch the surface of the
object to be polished.
[0007] FIG. 1 shows a schematic view of a polishing pad in the
prior art. The polishing pad 1 includes a bottom layer 10 and an
abrasive layer 30. The bottom layer 10 includes a non-woven fabric
12 wrapped in a polyurethanes (PU) resin 11. The abrasive layer 30,
coated on the bottom layer 10, is made of a PU resin 31, and has a
plurality of drop-shaped cells 32. Though no glue or adhesive is
used, the polishing pad 1 in the prior art has the following
disadvantages. As the drop-shaped cell 32 has the profile of a
short water drop, and the depth thereof does not exceed one half of
the overall thickness of the abrasive layer 30, only a limited
amount of the slurry and scraps generated during the abrasion can
be stored therein. Therefore, the drop-shaped cells 32 are easily
filled by the scraps generated in abrasion and gradually become
smaller, thus reducing the polishing effect or scratching the
surface of the workpiece to be polished, and also shortening the
service life of the polishing pad 1. Moreover, the polishing pad 1
is poorly buffered when put under a large downward force.
[0008] Therefore, it is necessary to provide a polishing pad having
an insulation layer 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
an insulation layer. The polishing pad comprises a bottom layer, an
insulation layer, and an abrasive layer. The bottom layer comprises
a fabric layer wrapped in a high polymer. The insulation layer is
disposed on the bottom layer. The abrasive layer is disposed on the
insulation layer. The abrasive layer is a high polymeric elastomer
and has a plurality of columnar-like cells.
[0010] The present invention is further directed to a method for
making a polishing pad. The method comprises the steps of: (a)
providing a bottom layer, in which the bottom layer comprises a
fabric layer wrapped in a high polymer and has a surface; (b)
forming an insulation layer on the surface of the bottom layer; (c)
forming a high polymeric elastomer on the insulation layer; (d)
curing the high polymeric elastomer to form an abrasive layer, in
which the abrasive layer has a plurality of columnar-like cells;
and (e) abrading a surface of the abrasive layer so that the
abrasive layer has a plurality of surface openings.
[0011] In the present invention, the insulation layer prevents the
slurry from infiltrating into the bottom layer during the polishing
process so as to improve polishing effect and quality. In a
preferred embodiment, the columnar-like cells are distributed over
a thickness that is at least one half of the overall thickness of
the abrasive layer, and the depth of the columnar-like cells is
greater than one half of the overall thickness of the abrasive
layer. Therefore, when applied in the polishing process, the
polishing pad may store a large amount of the slurry and scraps
generated during abrasion, thus improving the polishing efficiency
and preventing the surface of the workpiece to be polished from
being scratched. Moreover, the polishing pad is more effectively
buffered when put under a large downward force.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic view of a polishing pad in the prior
art;
[0013] FIG. 2 is a schematic view of a polishing pad according to a
preferred embodiment of the present invention; and
[0014] FIG. 3 is a flow chart of a method for making a polishing
pad according to a preferred embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The present invention provides a polishing pad, which is
applied in a chemical mechanical polishing (CMP) process to abrade
or polish a workpiece to be polished. The workpiece to be polished
comprises, but is not limited to, a semiconductor, a storage medium
substrate, an integrated circuit (IC), an LCD flat glass, an
optical glass, or a photoelectric panel.
[0016] FIG. 2 shows a schematic view of a polishing pad according
to a preferred embodiment of the present invention. The polishing
pad 4 comprises a bottom layer 50, an insulation layer 60, and an
abrasive layer 70. The bottom layer 50 comprises a fabric layer 52
wrapped in a high polymer 51. In this embodiment, the fabric layer
52 is a non-woven fabric, and is made of polypropylene (PP),
polyethylene terephthalate (PET), nylon, or a mixer thereof. The
high polymer 51 is a continuous foam, and is made of polyurethanes
(PU), PP, PET, a high-polymer resin, or a mixer thereof. In this
embodiment, the fabric layer 52 is made of PET, and the high
polymer 51 is made of PU.
[0017] The insulation layer 60 is disposed on the bottom layer 50.
The insulation layer 60 is made of PU, PP, PET, a high-polymer
resin, a thin metal layer, a metal powder, or any other material
that can be used for insulation. In this embodiment, the insulation
layer 60 comprises PU, dimethylformamide (DMF), and methyl ethyl
ketone (MEK). The insulation layer 60 is coated (for example,
roll-coated or blade-coated) on the bottom layer 50; however, it
should be understood that, the insulation layer 60 may also be
formed on the bottom layer 50 by roll-printing, transferring, or
other manner. Therefore, the insulation layer 60 is bonded to the
bottom layer 50 without using adhesive. Preferably, the bottom
layer 50 has a surface 53 which is flat. A fiber portion 54 of the
fabric layer 52 is exposed to the surface 53, such that the
insulation layer 60 further enwraps the exposed fiber portion 54,
resulting in an improved bond between the insulation layer 60 and
the bottom layer 50.
[0018] The abrasive layer 70 is disposed on the insulation layer
60, and has a plurality of columnar-like cells 72. The abrasive
layer 70 is a high polymeric elastomer 71, and is coated (for
example, roll-coated or blade-coated) on the insulation layer 60;
however, it should be understood that, the abrasive layer 70 may
also be formed on the insulation layer 60 by roll-printing,
transferring, or other manner. Therefore, the abrasive layer 70 is
bonded to the insulation layer 60 without using adhesive. The
abrasive layer 70 is made of PU, PP, PET, a high-polymer resin, or
a mixer thereof. In this embodiment, the abrasive layer 70 is made
of PU. The columnar-like cells 72 are distributed over a thickness
that is at least one half of the overall thickness of the abrasive
layer 70. In this embodiment, the columnar-like cells 72 are
columnar-shaped, and the depth of the columnar-like cells 72 is
greater than one half of the overall thickness of the abrasive
layer 70. The columnar-like cells 72 properly communicates with
each other.
[0019] In this embodiment, the polishing pad 4 has a compression
ratio of 5% to 50%, a compression-recovery ratio greater than 80%,
a thickness of 0.5 to 3.0 mm, and a density of 0.2 to 0.6
g/cm3.
[0020] FIG. 3 shows a flow chart of a method for making a polishing
pad according to a preferred embodiment of the present invention.
Referring to FIGS. 2 and 3, and Step S31, a bottom layer 50 is
provided. The bottom layer 50 comprises a fabric layer 52 wrapped
in a high polymer 51 and has a surface 53. In this embodiment, the
bottom layer 50 is formed by the following steps. First, a fabric
layer 52 is provided. The fabric layer 52 may be an ordinary fiber
non-woven fabric or a superfine fiber non-woven fabric, and is made
of PP, PET, nylon, or a mixer thereof. In this embodiment, the
fabric layer 52 is made of PET.
[0021] Then, the fabric layer 52 is immersed in a high-polymer
solution, such that the high-polymer solution enwraps the fabric
layer 52. The high-polymer solution may be a PU solution, a PP
solution, a PET solution, a high-polymer resin solution, or a mixer
thereof. In this embodiment, the high-polymer solution is a PU
solution, containing 13% PU resin, 3% surfactant, 9% pigment, and
75% DMF. Finally, the high-polymer solution is cured to form the
bottom layer 50.
[0022] Referring to Step S32, an insulation layer 60 is formed on
the surface 53 of the bottom layer 50. In this embodiment, the
insulation layer 60 is formed on the bottom layer 50 by coating
(for example, roll-coating or blade-coating); however, it should be
understood that, the insulation layer 60 may also be formed on the
bottom layer 50 by roll-printing, transferring, or other manner.
The insulation layer 60 is made of PU, PP, PET, a high-polymer
resin, a thin metal layer, a metal powder, or other insulation
material. In this embodiment, the insulation layer 60 comprises 17%
PU and 83% MEK.
[0023] Preferably, a fiber portion 54 of the fabric layer 52 in
Step S31 is exposed to the surface 53 so that the insulation layer
60 in Step S32 further enwraps the exposed fiber portion 54,
resulting in a stronger bond between the insulation layer 60 and
the bottom layer 50. It should be noted that the insulation layer
60 is bonded to the bottom layer 50 without using adhesive.
[0024] Referring to Step S33, a high polymeric elastomer 71 is
formed on the insulation layer 60. In this embodiment, the high
polymeric elastomer 71 is formed on the insulation layer 60 by
coating (for example, roll-coating or blade-coating); however, it
should be understood that, the high polymeric elastomer 71 may also
be formed on the insulation layer 60 by roll-printing,
transferring, or other manner. The high polymeric elastomer 71 may
be a PU solution, a PP solution, a PET solution, a high-polymer
resin solution, or a mixer thereof. In this embodiment, the high
polymeric elastomer 71 is a PU solution, containing 15% PU resin,
3% surfactant, 15% pigment, and 67% DMF.
[0025] Referring to Step S34, the bottom layer 50, the insulation
layer 60, and the high polymeric elastomer 71 are immersed in a
curing solution so as to cure the high polymeric elastomer 71 to
form an abrasive layer 70, and generate a plurality of
columnar-like cells 72 in the abrasive layer 70. The columnar-like
cells 72 properly communicate with each other. In this embodiment,
the curing solution comprises DMF and water, and has a
concentration of 15%.
[0026] Referring to Step S35, DMF is rinsed with hot water. Then,
referring to Step S36, a drying step is carried out so as to obtain
a semi-finished polishing pad having no exposed surface openings.
Finally, referring to Step S37, a surface of the abrasive layer 70
is abraded such that the abrasive layer 70 has a plurality of
surface openings, and scraps are removed by vacuum suction, so as
to fabricate the polishing pad 4.
[0027] The polishing pad 4 fabricated according to this embodiment
has a compression ratio of 28.30%, a compression-recovery ratio of
95.56%, a thickness of 1.6 mm, a density of 0.29 g/cm3, and a
hardness of 36 Shore A.
[0028] In the present invention, the insulation layer 60 prevents
the slurry from infiltrating into the bottom layer 50 during the
polishing process, so as to improve the polishing effect and
quality. Moreover, the columnar-like cells 72 are distributed over
a thickness that is at least one half of the overall thickness of
the abrasive layer 70, and the depth of the columnar-like cells 72
is greater than one half of the overall thickness of the abrasive
layer 70. Therefore, when applied in the polishing process, the
polishing pad 4 may store a large amount of the slurry and scraps
generated during the abrasion, thus improving the polishing
efficiency and preventing the surface of the workpiece to be
polished from being scratched. Moreover, the polishing pad 4 is
more effectively buffered when put under a large downward
force.
[0029] 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.
* * * * *