U.S. patent application number 11/175212 was filed with the patent office on 2007-01-11 for polishing pad and method of producing same.
This patent application is currently assigned to San Fang Chemical Industry Co., Ltd.. Invention is credited to Chung-Chih Feng, Yung-Chang Hung, I-Peng Yao.
Application Number | 20070010175 11/175212 |
Document ID | / |
Family ID | 37596733 |
Filed Date | 2007-01-11 |
United States Patent
Application |
20070010175 |
Kind Code |
A1 |
Feng; Chung-Chih ; et
al. |
January 11, 2007 |
Polishing pad and method of producing same
Abstract
The present invention relates to a method of producing a
polishing pad, comprising steps of: (a) providing a base material
comprising a plurality of fibers; said base material having a
surface for polishing a substrate; (b) impregnating the surface of
the base material with an elastomer solution; (c) curing the
elastomer impregnated in the surface of the base material to form a
plurality of first continuous pores embedded in the elastomer and
fibers; (d) impregnating the surface of the base material and
elastomer obtained in the step (c) with a condition polymer
solution; and (e) curing the condition polymer impregnated in the
surface of the base material and elastomer and partially filling
the condition polymer into the first continuous pores to form a
plurality of second continuous pores.
Inventors: |
Feng; Chung-Chih;
(Kaohsiung, TW) ; Yao; I-Peng; (Kaohsiung, TW)
; Hung; Yung-Chang; (Kaohsiung, TW) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
San Fang Chemical Industry Co.,
Ltd.
|
Family ID: |
37596733 |
Appl. No.: |
11/175212 |
Filed: |
July 7, 2005 |
Current U.S.
Class: |
451/41 ;
451/532 |
Current CPC
Class: |
B24B 37/30 20130101;
B24D 11/001 20130101; B24D 13/147 20130101 |
Class at
Publication: |
451/041 ;
451/532 |
International
Class: |
B24B 7/30 20060101
B24B007/30; B24D 11/00 20060101 B24D011/00; B24B 1/00 20060101
B24B001/00 |
Claims
1. A method of producing a polishing pad, comprising steps of: (a)
providing a base material comprising a plurality of fibers; said
base material having a surface for polishing a substrate; (b)
impregnating the surface of the base material with an elastomer
solution; (c) curing the elastomer impregnated in the surface of
the base material to form a plurality of first continuous pores
embedded in the elastomer and fibers; (d) impregnating the surface
of the base material and elastomer obtained in the step (c) with a
condition polymer solution; and (e) curing the condition polymer
impregnated in the surface of the base material and elastomer and
partially filling the condition polymer into the first continuous
pores to form a plurality of second continuous pores.
2. The method according to claim 1, wherein the base material is a
non-woven fabric.
3. The method according to claim 2, wherein the base material is a
rolled non-woven fabric.
4. The method according to claim 1, wherein the fibers are selected
from the group consisting of a single fiber and composite
fibers.
5. The method according to claim 2, wherein the fibers are
composite fibers.
6. The method according to claim 2, wherein the fibers are made of
at least one material selected from the group consisting of
polyamide, terephthalamide, polyester, polymethyl methacrylate,
polyethylene terephthalate, and polyacrylonitrile.
7. The method according to claim 1, wherein a length of the fibers
is from 0.5 cm to 10.5 cm.
8. The method according to claim 1, wherein the elastomers are foam
resins.
9. The method according to claim 1, wherein the elastomers are at
least one selected from the group consisting of polyamide,
polycarbonate, polyaminonitrile, polymethacrylate, epoxyl resin,
phenolic resins, polymethyl methacrylate, polyaminoester,
vinylbenzene polymer, acrylic resin, and polyurethane.
10. The method according to claim 1, wherein step (b) further
comprises impregnating the entire base material with the elastomer
solution.
11. The method according to claim 1, further comprising a step (c1)
of washing the surface of the base material after the step (c).
12. The method according to claim 11, further comprising a step
(c2) of drying the surface of the base material after the step
(c1).
13. The method according to claim 1, further comprising a step (c3)
of mechanically polishing the surface of the base material and the
elastomers before the step (d).
14. The method according to claim 1, wherein the condition polymers
are detergent polymers, hardness mediating polymers, saturation
degree mediating polymers, modulus mediating polymers, or
hydrophilicity mediating polymers.
15. The method according to claim 1, wherein the condition polymers
are at least one selected from the group consisting of polyamide,
polycarbonate, polyaminonitrile, polymethacrylate, epoxyl resin,
phenolic resins, polymethyl methacrylate, polyaminoester,
vinylbenzene polymer, acrylic resin, polyurethane,
hydroxyl-containing polymer, silicon-containing hydrophobe, and
fluoride-containing hydrophobe.
16. The method according to claim 1, wherein step (d) further
impregnating the entire base material with the condition polymer
solution.
17. The method according to claim 1, further comprising a step (e1)
of washing the surface of the base material after the step (e).
18. The method according to claim 17, further comprising a step
(e2) of drying the surface of the base material after the step
(e1).
19. The method according to claim 1, further comprising a step (e3)
of mechanically polishing the surface of the base material, the
elastomers and the condition polymers.
20. The method according to claim 1, wherein steps (b) and (c) are
repeated for several times.
21. The method according to claim 1, wherein steps (d) and (e) are
repeated for several times.
22. The method according to claim 1, wherein the elastomers are
different from the condition polymers.
23. The method according to claim 1, wherein the second continuous
pores have a pore size ranging from 0.1 .mu.m to 500 .mu.m.
24. A polishing pad comprising a base material having a surface for
polishing a substrate, wherein the surface comprises a plurality of
fibers, at lease one elastomer and at least one condition polymer,
and a plurality of continuous pores are embedded in the fibers,
elastomers and condition polymers.
25. The polishing pad according to claim 24, wherein the base
material is a non-woven fabric.
26. The polishing pad according to claim 25, wherein the base
material is a rolled non-woven fabric.
27. The polishing pad according to claim 24, wherein the fibers are
selected from the group consisting of a single fiber and composite
fibers.
28. The polishing pad according to claim 27, wherein the fibers are
composite fibers.
29. The polishing pad according to claim 25, wherein the fibers are
made of at least one material selected from the group consisting of
polyamide, terephthalamide, polyester, polymethyl methacrylate,
polyethylene terephthalate, polyacrylonitrile, and mixture
thereof.
30. The polishing pad according to claim 24, wherein a length of
the fibers is from 0.5 cm to 10.5 cm.
31. The polishing pad according to claim 24, wherein the elastomers
are foam resins.
32. The polishing pad according to claim 24, wherein the elastomers
are at least one selected from the group consisting of polyamide,
polycarbonate, polyaminonitrile, polymethacrylate, epoxyl resin,
phenolic resins, polymethyl methacrylate, polyaminoester,
vinylbenzene polymer, acrylic resin, and polyurethane.
33. The polishing pad according to claim 24, wherein the condition
polymers are detergent polymers, hardness mediating polymers or
hydrophilicity mediating polymers.
34. The polishing pad according to claim 33, wherein the condition
polymers are at least one selected from the group consisting of
polyamide, polycarbonate, polyaminonitrile, polymethacrylate,
epoxyl resin, phenolic resins, polymethyl methacrylate,
polyaminoester, vinylbenzene polymer, acrylic resin, polyurethane,
hydroxyl-containing polymer, silicon-containing hydrophobe, and
fluoride-containing hydrophobe.
35. The polishing pad according to claim 24, wherein the elastomers
are different from the condition polymers.
36. The polishing pad according to claim 24, wherein the continuous
pores have a pore size ranging from 0.1 .mu.m to 500 .mu.m.
37. A method of polishing a substrate comprising using the
polishing pad according to claim 24 to polish a surface of the
substrate.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a polishing pad for use in
a chemical mechanical polishing, and a method for producing the
polishing pad.
[0003] 2. Description of the Related Art
[0004] Chemical mechanical polishing (CMP) is a procedure for
planarizing the surface of a substrate with a polishing pad. CMP is
generally applied in polishing lens, mirrors, substrates of liquid
crystal displays, silicon wafers, and oxidation and/or metal layers
on silicon wafers.
[0005] U.S. Pat. No. 6,454,634 discloses a polishing pad produced
by a method comprising the steps of pouring thermoplastic foam
resin in a circular mold to form a casting, skiving the casting
into sheets, and mechanically machining macro-channels into the
surface of the sheets. The polishing pad comprises a polymeric
matrix made of polyurethane and hollow elastic polymeric
micropheres are distributed therein. The cell size and distribution
in the polishing pad made of thermoplastic foam resin highly depend
on the distribution of each component in a mixture for molding and
also depend on the distribution of temperature of the circular
mold. It is difficult to even out the distribution of each
component in a mixture for molding in a circular mold. Furthermore,
because of viscoelastic property of polyurethane, a knife used in a
skiving step cannot be located on the edge of the sheet precisely
and subsequently influences the flatness, size and distribution of
the cells. These factors reduce the batch uniformity when producing
the polishing pad, and thus a polishing process involved becomes
complicated. In another aspect, the cells of the polishing pad in
this patent are discontinuous for each other, so that polishing
fluid cannot flow smoothly and polishing particles cannot diffuse
evenly. Besides, the residues formed during polishing easily stay
on the surface of the polishing pad and their removal is poor; as a
result, the residues scrap and damage the substrate to be
polished.
[0006] U.S. Patent Application Publication No. 2004/0224623 A1
discloses a polishing pad having a plate-like shape. The polishing
pad comprises fibers and a resin fixing the fibers to form the
plate-like shape. The polishing pad has at least one surface layer
that is substantially non-porous and comprises organic fibers and a
resin fixing the organic fibers. A surface of the surface layer of
the polishing pad is mechanically polished, so that the surface
layer has a surface on which the organic fibers are exposed. This
application also discloses layering a resin-impregnated sheet-form
fiber base material and a resin-unimpregnated sheet-form fiber base
material and unifying them by thermocompression molding to form a
polishing pad. However, the thermocompression molding step easily
leads to uneven space formed between the layers. As a result,
hardness, flatness, compression ratio, elasticity, and recovery
ratio of the surface of the polishing pad are all affected. The
density variation of the layers thermocompression molded occurs
during molding. Besides, the method of producing with the condition
at high temperature (such as 300.degree. C.) and high pressure
(such as 196 kN/m) chars and hardens the surface of the polishing
pad, and then the polishing pad scraps and damages the substrate to
be polished. Furthermore, when producing the polishing pad,
migration easily occurs and the polymers cannot be distributed in
the sheet-form fiber base evenly. Heat for laminating also affects
the quality, such as hardness, elasticity, compression rate, and
density of the polishing pad. The factors all reduce the efficiency
of polishing.
SUMMARY OF THE INVENTION
[0007] One object of the present invention is to provide to a
method of producing a polishing pad, comprising the steps of:
[0008] (a) providing a base material comprising a plurality of
fibers; said base material having a surface for polishing a
substrate;
[0009] (b) impregnating the surface of the base material with an
elastomer solution;
[0010] (c) curing the elastomer impregnated in the surface of the
base material to form a plurality of first continuous pores
embedded in the elastomer and fibers;
[0011] (d) impregnating the surface of the base material and
elastomer obtained in step (c) with a condition polymer solution;
and
[0012] (e) curing the condition polymer impregnated in the surface
of the based material and elastomer and partially filling the
condition polymer into the first continuous pores to form a
plurality of second continuous pores.
[0013] Another object of the present invention is to provide a
polishing pad comprising a base material having a surface for
polishing a substrate, wherein the surface comprises a plurality of
fibers, at least one elastomer and at least one condition polymer,
and a plurality of continuous pores are embedded in the fibers,
elastomer and condition polymer.
[0014] A further object of the present invention is to provide a
method of polishing a substrate comprising using a polishing pad to
polish a surface of the substrate, wherein the polishing pad
comprises a base material having a surface for polishing the
substrate, wherein the surface comprises a plurality of fibers, at
least one elastomer and at least one condition polymer, and a
plurality of continuous pores are embedded in the fibers, elastomer
and condition polymer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 illustrates views under a transmission electron
microscope of a semi-product (1)(a) and a polishing pad (2)(b).
DETAILED DESCRIPTION OF THE INVENTION
[0016] The present invention provides a method of producing a
polishing pad, comprising the steps of:
[0017] (a) providing a base material comprising a plurality of
fibers; said base material having a surface for polishing a
substrate;
[0018] (b) impregnating the surface of the base material with an
elastomer solution;
[0019] (c) curing the elastomer impregnated in the surface of the
base material to form a plurality of first continuous pores
embedded in the elastomer and fibers;
[0020] (d) impregnating the surface of the base material and
elastomer obtained in the step (c) with a condition polymer
solution; and
[0021] (e) curing the condition polymer impregnated in the surface
of the base material and elastomer and partially filling the
condition polymer into the first continuous pores to form a
plurality of second continuous pores.
[0022] According to the invention, any base material comprising
fibers can be applied in the invention. Preferably, the base
material is a non-woven fabric, and more preferably, the base
material is a rolled non-woven fabric. The rolled nonwoven fabric
can be used in a roll to roll way that improves batch uniformity in
comparison with a conventional method of producing a single
polishing pad involving molding or casting.
[0023] As used herein, the term "fiber" refers to a single fiber or
composite fibers, preferably, composite fibers. The fiber is
selected in accordance with the substrate to be polished. Artisans
skilled in this field can choose suitable kinds of fibers and
coordinate the elastomer and/or condition polymer with the fibers
according to the disclosure of the specification. 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
mixture thereof.
[0024] The fibers of the surface of the base material provide
protrusions for polishing and also provide a scaffold allowing the
elastomers and condition polymers deposed in the space defined by
the scaffold. In order to have a satisfied function, the length of
the fibers is preferably from 0.5 cm to 10.5 cm, i.e., defined as a
"short fiber" in this field.
[0025] As used herein, the term "elastomer," also known as "elastic
polymer," refers to a type of polymer that exhibits rubber-like
qualities. When polishing, the elastomer serves as a good buffer to
avoid scraping the surface of the substrate to be polished. In one
preferred embodiment of the invention, the elastomers are foam
resins. As used herein, the term "foam resin" refers to a material
containing a thermoplastic resin and a thermodecomposing foaming
agent. Preferably, the elastomers are at least one selected from
the group consisting of polyamide, polycarbonate, polyaminonitrile,
polymethacrylate, epoxyl resin, phenolic resins, polymethyl
methacrylate, polyaminoester, vinylbenzene polymer, acrylic resin,
and polyurethane.
[0026] In step (b) of the method, the manner of impregnating the
base material with an elastomer solution can be any conventional
method of impregnating. The conditions for impregnation are well
known to artisans skilled in this field. Suitable solvents used in
the elastomer solution include dimethylformamide (DMF). The
elastomer solution optionally comprises additives such as a
detergent. Preferably, the elastomer has a concentration ranging
from 2 wt % to 60 wt % in the elastomer solution.
[0027] Preferably, step (b) further comprises impregnating the
entire base material with the elastomer solution.
[0028] In step (c) of the method, the manner of curing the
elastomer impregnated in the base material to form a plurality of
first continuous pores contained in the elastomers and fibers can
be any conventional method of curing. In one embodiment of the
invention, the base material is put into a curing solution for
curing. Preferably, the curing solution comprises 0 to 40 wt %
dimethylformamide in water. The conditions for curing are well
known to artisans skilled in this field. Preferably, the curing is
carried out at room temperature and pressure.
[0029] In one preferred embodiment of the invention, the method of
producing a polishing pad further comprises a step (c1) of washing
the base material after step (c). The manner of washing can be any
conventional method of washing. In one embodiment of the invention,
water is used in washing and extrusion wheels are optionally used.
The conditions for washing are well known to artisans skilled in
this field. Preferably, the base material is washed in water at 50
to 90.degree. C. and then subjected to the extrusion wheels several
times.
[0030] In one more preferred embodiment of the invention, the
method of producing a polishing pad further comprises a step (c2)
of drying the base material after step (c1). The manner of drying
can be any conventional method of drying. The conditions for drying
are well known to artisans skilled in this field. In one embodiment
of the invention, the drying is air-drying, and the drying
temperature is in the range of 100.degree. C. to 160.degree. C.
[0031] Preferably, the method of producing a polishing pad further
comprises a step (c3) of mechanically polishing the surface of the
base material and the elastomer before step (d). The manner of
mechanically polishing can be any conventional method of
mechanically polishing, such as using a sand blast. The conditions
for mechanically polishing are well known to artisans skilled in
this field. More preferably, the fibers are exposed to the surface
of the base material after mechanically polishing.
[0032] As used herein, the term "condition polymer" refers to a
polymer for use in changing properties of the surface of the base
material obtained in the step (c) of the method according to the
invention. Because a plurality of first continuous pores are formed
and contained in the elastomer and fibers, some properties such as
hardness, saturation degree, modulus, or hydrophilicity of the
polishing pad may not be satisfied during application. The
condition polymers serve as a condition agent for adjusting all of
these properties to the best when application. The second
continuous pores formed in the polishing pad are smaller than the
first continuous pores. The kind and amount of the condition
polymers can be determined according to the kind and amount of the
elastomer and the substrate to be polished. In one preferred
embodiment of the invention, the condition polymers are detergent
polymers, hardness mediating polymers, saturation degree mediating
polymers, modulus mediating polymers, or hydrophilicity mediating
polymers. In one more preferred embodiment of the invention, the
condition polymers are at least one selected from the group
consisting of polyamide, polycarbonate, polyaminonitrile,
polymethacrylate, epoxyl resin, phenolic resins, polymethyl
methacrylate, polyaminoester, vinylbenzene polymer, acrylic resin,
polyurethane, hydroxyl-containing polymer, silicon-containing
hydrophobe, and fluoride-containing hydrophobe. For example, the
hardness mediating polymers have the ability to improve the
hardness of the pad, and furthermore, the working temperature
thereof is lower than the deformation temperature of the base
material. Preferably, polyurethane, polymethacrylate and polymethyl
methacrylate are applicable as the hardness mediating polymers,
which benefit the polishing efficiency without affecting the
uniformity and flatness of the pad. In another aspect, the
hydrophilicity mediating polymers comprise hydrophile and
hydrophobe. The hydroxyl-containing polymers are suitable for the
hydrophile. The hydrophobe is preferably silicon- or
fluoride-containing hydrophobe.
[0033] In step (d) of the method, the manner of impregnating the
surface of the base material and elastomers obtained in step (c)
with a condition polymer solution can be any conventional method of
impregnating. The conditions for impregnation the base material
with a condition polymer are well known to artisans skilled in this
field. Suitable solvents used in the condition polymer solution
include water, methyl-ethyl ketone (MEK) and toluene. Among the
solvents, water is preferred because it has the ability to adjust a
broad range of viscosity and polymer content of the condition
polymer solution. Furthermore, water permeates into the base
material much easily. The condition polymer solution optionally
comprises additives such as resistant form solution (deformer), and
thickener. Preferably, the condition polymer has a concentration
ranging from 10 wt % to 100 wt % in the elastomer solution.
[0034] Preferably, step (d) comprises impregnating the entire base
material with the condition solution. In the embodiment, the
polishing pad can continuously provide a surface for polishing, and
the number times of retooling the polishing pad is thus
reduced.
[0035] In step (e) of the method, the manner of curing the
condition polymers impregnated in the surface of the base material
and the elastomers can be any conventional method for curing. The
conditions for curing are well known to artisans skilled in this
field.
[0036] In one preferred embodiment of the invention, the method of
producing a polishing pad further comprises a step (e1) of washing
the surface of the base material after step (e). The manner of
washing can be any conventional method of washing. The conditions
for washing are well known to artisans skilled in this field.
Preferably, the base material is washed in water at 50 to
90.degree. C. and then subjected to the extrusion wheels for
several times.
[0037] In one more preferred embodiment of the invention, the
method of producing a polishing pad further comprises a step (e2)
of drying the surface of the base material after step (e1). The
manner of drying can be any conventional method of drying. The
conditions for drying are well known to artisans skilled in this
field. In one embodiment of the invention, the drying is
air-drying, and the drying temperature is in the range of
100.degree. C. to 170.degree. C.
[0038] Preferably, the method of producing a polishing pad further
comprises a step (e3) of mechanically polishing the surface of the
base material, the elastomers and the condition polymers after step
(e2). The manner of mechanically polishing can be any conventional
method of mechanically polishing. The conditions for mechanically
polishing are well known to artisans skilled in this field. More
preferably, the fibers are exposed to the surface of the base
material after mechanically polishing.
[0039] In one preferred embodiment of the invention, steps (b) and
(c) are repeated several times. The kind of the elastomer used in
each time can be different or the same.
[0040] In another preferred embodiment of the invention, steps (d)
and (e) are repeated several times. The kind of the condition
polymer used in each time can be different or the same.
[0041] According to the present invention, the elastomers are
different from or the same as the condition polymers. In one
preferred embodiment of the invention, the elastomers are different
from the condition polymers.
[0042] The polishing pad produced according to the method of the
invention has a plurality of continuous pores embedded in the
elastomers, condition polymers and fibers. The continuous pores of
the polishing pad have an even size, which benefit flow of
polishing fluid and distribution of polishing particle and removal
of polishing residues. In a preferred embodiment of the invention,
the continuous pores have a pore size ranging from 0.1 .mu.m to 500
.mu.m.
[0043] The polishing pad produced according to the method of the
invention can avoid the defects of conventional polishing pads
produced by molding thermoplastic foam resin because the base
material of the invention is not formed by molding and its
properties will not be influenced by molding. Both the flatness and
batch uniformity of the polishing pad according to the invention
are better than conventional ones. Furthermore, the method of the
invention is also free of thermocompression and lamination, so that
the polishing pad according to the invention does not damage the
surface of the substrate to be polished. Besides, the polishing
efficiency is satisfied when the polishing pad according to the
invention is applied.
[0044] The invention also provides a polishing pad comprising a
base material, which has a surface for polishing a substrate,
wherein the surface comprises a plurality of fibers, elastomers and
condition polymers, and a plurality continuous pores are embedded
in the fibers, elastomers and condition polymers.
[0045] The present invention also provides a method of polishing a
substrate comprising using a polishing pad to polish a surface of
the substrate, wherein the polishing pad comprising a base material
having a surface for polishing the substrate, wherein the surface
comprises a plurality of fibers, at least one elastomer and at
least one condition polymer, and a plurality of continuous pores
are embedded in the fibers, elastomer and condition polymer.
[0046] The following examples are given for the purpose of
illustration only but not intended to limit the scope of the
present invention.
EXAMPLE
[0047] Base Material: Composite fibers of Nylon.RTM. and
polyethylene terephthalate (PET) with a fineness of 3 denier formed
a non-woven fabric base material, wherein the ratio of Nylon.RTM.
to PET is 7:3. The thickness of the base material was 2.25 mm, the
density was 0.22 g/cm.sup.3 and the weight of area unit was 496
g/m.sup.2.
[0048] Impregnating: The base material was impregnated in an
elastomer solution comprising 49 wt % polyaminoester, 49 wt %
solvent and 2 wt % detergent.
[0049] Curing: The base material, after impregnating, was put into
a curing solution comprising 18 wt % dimethylformamide in water to
mold the elastomer impregnated in the fibers.
[0050] Washing: The residues and the excess curing solution were
removed by extrusion wheels. The base material was then washed in
water at 80.degree. C. and then subjected to the extrusion wheels
for several times.
[0051] Drying: The base material, after washing, was then dried at
140.degree. C.
[0052] Publishing: After drying, the base material was subjected to
mechanically polishing with #150 and #400 sand paper at 1200 and
1300 rpm, and a 1.28 mm semi-product (1) with a flat surface was
obtained.
[0053] Impregnating and curing: The 1.28 mm semi-product was
impregnated in a condition polymer solution containing 75 wt %
polymethyl methacrylate. The extrusion wheels were applied for
assisting impregnating. The impregnated semi-product was then
subjected to curing at 125.degree. C.
[0054] Drying: The base material was then dried for removing excess
water, and a polishing pad (2) was obtained.
[0055] Assaying: The polishing pad (2) obtained and the
semi-product (1) were subjected to property assays. The material of
the substrate to be polished was silicon dioxide, and the equipment
used was IPEC372. The results were shown in Table 1 and FIG. 1.
They proved that both the hardness and compression rate are
improved after the treatment with condition polymers. The density
was also increased after the treatment. TABLE-US-00001 TABLE 1
Hardness of Hardness of Compression Density shore A shore D rate
(%) (g/cm.sup.3) Semi-product (1) 75 30 3.5 0.45 Polishing pad (2)
95 54 2.2 0.70
[0056] The polishing pad (2) obtained and the semi-product (1) were
positioned on a chemical mechanical polishing apparatus for
assaying polishing properties. The results were shown in Table 2.
They showed that the removal rate is raised after the treatment
with condition polymers, and the non-uniformity is decreased also.
TABLE-US-00002 TABLE 2 Removal rate (.ANG./min) Non-uniformity (%)
Semi-product (1) 1556 5.04 Polishing pad (2) 1855 4.50
[0057] While embodiments of the present invention have been
illustrated and described, various modifications and improvements
can be made by persons 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 is
not limited to the particular forms as illustrated, and that all
the modifications not departing from the spirit and scope of the
present invention are within the scope as defined in the appended
claims.
* * * * *