U.S. patent application number 16/586545 was filed with the patent office on 2020-02-06 for abrasive pad.
This patent application is currently assigned to FURUKAWA ELECTRIC CO., LTD.. The applicant listed for this patent is FURUKAWA ELECTRIC CO., LTD.. Invention is credited to Takashi NARIMATSU, Shota SUGIYAMA, Nobutoshi YOKOTA.
Application Number | 20200039023 16/586545 |
Document ID | / |
Family ID | 63676386 |
Filed Date | 2020-02-06 |
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United States Patent
Application |
20200039023 |
Kind Code |
A1 |
YOKOTA; Nobutoshi ; et
al. |
February 6, 2020 |
ABRASIVE PAD
Abstract
An object of the present disclosure is to provide an abrasive
pad that is superior in abrading performance and abrasive slurry
discharging properties. An abrasive pad having an abrading part and
a groove part on an abrasive surface is provided in which a surface
of the groove part has a non-foamed part, and a foamed part is
exposed on a surface of the abrading part.
Inventors: |
YOKOTA; Nobutoshi; (Tokyo,
JP) ; SUGIYAMA; Shota; (Tokyo, JP) ;
NARIMATSU; Takashi; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FURUKAWA ELECTRIC CO., LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
FURUKAWA ELECTRIC CO., LTD.
Tokyo
JP
|
Family ID: |
63676386 |
Appl. No.: |
16/586545 |
Filed: |
September 27, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2018/012483 |
Mar 27, 2018 |
|
|
|
16586545 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B24B 37/26 20130101;
B24B 37/24 20130101; C08L 67/02 20130101; C08L 69/00 20130101; C08L
81/02 20130101; H01L 21/304 20130101 |
International
Class: |
B24B 37/26 20060101
B24B037/26; B24B 37/24 20060101 B24B037/24 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2017 |
JP |
2017-070780 |
Claims
1. An abrasive pad comprising an abrading part and a groove part on
an abrasive surface, wherein a surface of the groove part comprises
a non-foamed part, and a foamed part is exposed on a surface of the
abrading part.
2. The abrasive pad according to claim 1, wherein a maximum height
roughness (Rz) of the surface of the groove part is 10 .mu.m to 30
.mu.m, and a maximum height roughness (Rz) of the surface of the
abrading part is 30 .mu.m to 100 .mu.m.
3. The abrasive pad according to claim 1, wherein an arithmetic
mean roughness (Ra) of the surface of the groove part is 0.1 .mu.m
to 10 .mu.m, and an arithmetic mean roughness (Ra) of the surface
of the abrading part is 10 .mu.m to 45 .mu.m.
4. The abrasive pad according to claims 1, wherein a value of (the
maximum height roughness (Rz) of the surface of the abrading
part)-(the maximum height roughness (Rz) of the surface of the
groove part) is 20 .mu.m to 70 .mu.m.
5. The abrasive pad according to claims 1, wherein a value of (the
arithmetic mean roughness (Ra) of the surface of the abrading
part)-(the arithmetic mean roughness (Ra) of the surface of the
groove part) is 5 .mu.m to 35 .mu.m.
6. The abrasive pad according to claims 1, comprising a resin foam
formed from a thermoplastic resin that has a three-dimensional
bubble structure, wherein the thermoplastic resin is at least one
type of resin selected from a group of polyphenylene sulfide resin,
polyethylene terephthalate resin, and polycarbonate resin.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation application of
International Patent Application No. PCT/JP2018/012483 filed on
Mar. 27, 2018, which claims the benefit of Japanese Patent
Application No. 2017-070780, filed on Mar. 31, 2017. The contents
of these applications are incorporated herein by reference in their
entirety.
BACKGROUND
Technical Field
[0002] The present disclosure relates to an abrasive pad having a
superior abrading performance and superior abrasive slurry
discharging properties.
Background
[0003] Conventionally, in an abrasion process of a thin plate
member such as a magnetic disc that is installed in a hard disc
drive (HDD) or a semiconductor wafer, since work generating neither
a minute flaw nor a latent flaw on a surface of a processing target
object is required, smoothing mirror surface work is performed by
use of a non-woven fabric system or foam system abrasive pad while
supplying an abrasive slurry containing minute abrasive grains.
[0004] Not only the abradability but also the abrasive slurry
discharging properties are required on an abrasive pad for such
smoothing mirror surface work. Then, in order to improve the
balance between supplying and discharging the abrasive slurry (the
abrasive slurry discharging properties), an abrasive pad has been
proposed which has an abrasive layer with a groove on an abrasive
surface and in which a mean roughness (Ra) on an inner surface of
the groove is in a range of 1.0 to 5.0 .mu.m (Japanese Patent
Application Laid-Open No. 2006-186239).
[0005] In the abrasive pad of Japanese Patent Application Laid-Open
No. 2006-186239, however, since the groove is formed on a porous
material through cutting, and the inner surface of the groove is
formed into a non-porous surface by after-working such as laser
melting, the work becomes complex. In addition, nothing is
specified about the state (in particular, roughness) of the
abrasive surface of the abrasive layer, and thus, the abrasive pad
causes a problem in that the abradability may not be compatible
with the abrasive slurry discharging properties, resulting in a
problem in that superior smoothing mirror surface work cannot be
performed.
SUMMARY
[0006] The present disclosure is related to providing an abrasive
pad having a superior abrading performance and superior abrasive
slurry discharging properties.
[0007] According to a first aspect of the present disclosure, an
abrasive pad is provided which has an abrading part and a groove
part on an abrasive surface, and a surface of the groove part has a
non-foamed part, and a foamed part is exposed on a surface of the
abrading part.
[0008] In the abrasive pad according to the first aspect, the
abrasive surface has the abrading part configured to abrade a
processing target object which is an abrasion target and the groove
part configured to discharge an abrasive slurry supplied to the
abrasive pad when the processing target object is abraded from the
abrasive pad to an exterior of the abrasive pad. Since the foamed
part of the foam is exposed on the surface of the abrading part and
the surface of the groove part has the non-foamed part, a form
results in which a maximum height roughness (Rz) of the surface of
the abrading part is greater than a maximum height roughness (Rz)
of the surface of the groove part, and an arithmetic mean roughness
(Ra) of the surface of the abrading part is greater than an
arithmetic mean roughness (Ra) of the surface of the groove
part.
[0009] According to a second aspect of the present disclosure, in
the abrasive pad, the maximum height roughness (Rz) of the surface
of the groove part is 10 .mu.m to 30 .mu.m, and the maximum height
roughness (Rz) of the surface of the abrading part is 30 .mu.m to
100 .mu.m.
[0010] According to a third aspect of the present disclosure, in
the abrasive pad, the arithmetic mean roughness (Ra) of the surface
of the groove part is 0.1 .mu.m to 10 .mu.m, and the arithmetic
mean roughness (Ra) of the surface of the abrading part is 10 .mu.m
to 45 .mu.m.
[0011] According to a fourth aspect of the present disclosure, in
the abrasive pad, a value of (the maximum height roughness (Rz) of
the surface of the abrading part)-(the maximum height roughness
(Rz) of the surface of the groove part) is 20 .mu.m to 70
.mu.m.
[0012] According to a fifth aspect of the present disclosure, in
the abrasive pad, a value of (the arithmetic mean roughness (Ra) of
the surface of the abrading part)-(the arithmetic mean roughness
(Ra) of the surface of the groove part) is 5 .mu.m to 35 .mu.m.
[0013] According to a sixth aspect of the present disclosure, the
abrasive pad has a resin foam formed from a thermoplastic resin
that has a three-dimensional bubble structure, wherein
[0014] the thermoplastic resin is at least one type of resin
selected from a group of polyphenylene sulfide resin, polyethylene
terephthalate resin, and polycarbonate resin.
[0015] According to the aspects of the present disclosure, the
abrasive slurry can be discharged smoothly from the abrasive pad
due to the surface of the groove part having the non-foamed part.
Consequently, abrasion dust (abrasion residue) that is mixed with
the abrasive slurry through the abrasion process can be prevented
from staying on the abrasive pad. Additionally, since the abrasive
slurry can be discharged smoothly from the abrasive pad, an
increase in the temperature of the abrasive pad can be prevented.
On the other hand, since the foamed part is exposed on the surface
of the abrading part, that is, the surface of the abrading part is
rough, the abrading performance of the abrading part is improved,
and the abrading performance of the abrading part is also increased
by the abrasive slurry being captured by the exposed foamed
part.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a partial side sectional view of an abrasive pad
according to an embodiment of the present disclosure.
[0017] FIG. 2 is a partial side sectional view of a resin member
for use for an example of an abrasive pad production method
according to the embodiment of the present disclosure.
[0018] FIG. 3A is an overall explanatory drawing of a groove part
forming die member for use for the example of the abrasive pad
production method according to the embodiment of the present
disclosure, and FIG. 3B is a cross-sectional view of the groove
part forming die member taken along a line A-A.
[0019] FIG. 4 is an explanatory drawing of the example of the
abrasive pad production method according to the embodiment of the
present disclosure using the groove part forming die member.
DETAILED DESCRIPTION
[0020] Hereinafter, an abrasive pad according to an embodiment of
the present disclosure will be described with reference to the
accompanying drawings.
[0021] As illustrated in FIG. 1, in an abrasive pad 1 according to
the embodiment of the present disclosure, an abrasive surface 10,
which is a surface on an abrading side, has an abrading part 11 and
a groove part 12. The abrading part 11 is a part configured to
abrade a processing target object (not shown), which is an abrasion
target. The groove part 12 is a part configured to discharge
abrasive slurry that is supplied to the abrasive pad when abrading
the processing target object and abrasion dusts from the abrasive
surface 10 to an exterior.
[0022] The abrasive pad 1 includes a resin foam 15 having a surface
non-foamed layer 13, whose surface constitutes a non-foamed part,
and a foamed part 14 provided in an interior of the surface
non-foamed layer 13. In the abrasive pad 1, the foamed part 14 of
the resin foam 15 is exposed over substantially an overall surface
of the abrading part 11. Consequently, in the abrasive pad 1, a
surface of the abrading part 11 does not have the surface
non-foamed layer 13.
[0023] The foamed part 14 of the resin foam 15 constitutes a
three-dimensional bubble structure in which a plurality of bubbles
17 divided by bubble walls 16 are formed densely. Since the
three-dimensional bubble structure is exposed from the surface at
the abrading part 11, a form results in which inner surfaces of the
bubbles 17 are exposed on the surface of the abrading part 11.
Consequently, the surface of the abrading part 11 is of a porous
structure. At the abrading part 11, the foamed part 14 can be
exposed by removing the surface non-foamed layer 13 in advance
through an abrasion process or the like.
[0024] On the other hand, a surface of the groove part 12 has a
non-foamed part of the resin foam 15. That is, the surface of the
groove part 12 constitutes the surface non-foamed layer 13.
Bubbles, which are to be formed through a foaming process, are not
formed in the surface non-foamed layer 13. In the abrasive pad,
substantially an overall area of the surface of the groove part 12
constitutes the surface non-foamed layer 13, which is the
non-foamed part. Consequently, interiors of the bubbles 17, that
is, inner surfaces of the bubble walls 16 are not exposed from the
surface of the groove part 12, and hence, a porous structure is not
exposed.
[0025] From what has been described above, the surface of the
groove part 12, which constitutes the surface non-foamed layer 13,
is smooth, and the surface of the abrading part 11, from which the
foamed part 14 is exposed, is rougher than the surface of the
groove part 12. That is, the surface of the abrading part 11 takes
greater values for both a maximum height roughness (Rz) and an
arithmetic mean roughness (Ra) than those of the surface of the
groove part 12. In the present description, the "maximum height
roughness (Rz)" and the "arithmetic mean roughness (Ra)" mean
values measured with a laser microscope (VX-X150, made by KEYENCE
CORPORATION).
[0026] Although the maximum height roughness (Rz) of the surface of
the abrading part 11 is not particularly limited, it is preferable
that a lower limit value of the maximum height roughness (Rz) is,
for example, 20 .mu.m or greater from the viewpoint of improving
the abrading performance of the abrading part 11 due to the
roughness of the surface, is more preferable that the lower limit
value is 25 .mu.m or greater from the viewpoint of further
improving the abrading performance of the abrading part 11 as a
result of the abrasive slurry being captured on the inner surface
of the bubble walls 16 of the foamed part 14 that is exposed, and
is most preferable that the lower limit value is 30 .mu.m or
greater. On the other hand, it is preferable that an upper limit
value of the maximum height roughness (Rz) of the surface of the
abrading part 11 is, for example, 100 .mu.m or smaller from the
viewpoint of facilitating the production of the resin foam 15, is
more preferable that the upper limit value is 65 .mu.m or smaller,
and is most preferable that the upper limit value is 55 .mu.m or
smaller.
[0027] Although the arithmetic mean roughness (Ra) of the surface
of the abrading part 11 is not particularly limited, it is
preferable that a lower limit value of the arithmetic mean
roughness (Ra) is, for example, 10 .mu.m or greater from the
viewpoint of improving the abrading performance of the abrading
part 11 due to the roughness of the surface, is more preferable
that the lower limit value is 15 .mu.m or greater from the
viewpoint of further improving the abrading performance of the
abrading part 11 as a result of the abrasive slurry being captured
on the inner surface of the bubble walls 16 of the foamed part 14
that is exposed, and is most preferable that the lower limit value
is 25 .mu.m or greater. On the other hand, it is preferable that an
upper limit value of the arithmetic mean roughness (Ra) of the
surface of the abrading part 11 is, for example, 45 .mu.m or
smaller from the viewpoint of facilitating the production of the
resin foam 15, and is particularly preferable that the upper limit
value is 35 .mu.m or smaller.
[0028] Although the maximum height roughness (Rz) of the surface of
the groove part 12 is not particularly limited, it is preferable
that a lower limit value of the maximum height roughness (Rz) is,
for example, 10 .mu.m or greater from the viewpoint of facilitating
the production of the resin foam 15, and is particularly preferable
that the lower limit value is 15 .mu.m or greater. On the other
hand, it is preferable that an upper limit value of the maximum
height roughness (Rz) is, for example, 30 .mu.m or smaller from the
viewpoint of discharging the abrasive slurry from the abrasive pad
smoothly to prevent abrasion dust that is mixed into the abrasive
slurry through an abrasion process performed on the processing
target object from staying on the abrasive pad in an ensured
fashion, is more preferable that the upper limit value is 25 .mu.m
or smaller from the viewpoint of discharging the abrasive slurry
from the abrasive pad smoothly to thereby prevent the temperature
of the abrasive pad from increasing in an ensured fashion, and is
most preferable that the upper limit value is 20 .mu.m or
smaller.
[0029] Although the arithmetic mean roughness (Ra) of the surface
of the groove part 12 is not particularly limited, it is preferable
that a lower limit value of the arithmetic mean roughness (Ra) is,
for example, 0.1 .mu.m or greater from the viewpoint of
facilitating the production of the resin foam 15, and is
particularly preferable that the lower limit value is 0.5 .mu.m or
greater. On the other hand, it is preferable that an upper limit
value of the arithmetic mean roughness (Ra) is, for example, 10
.mu.m or smaller from the viewpoint of discharging the abrasive
slurry from the abrasive pad smoothly to prevent abrasion dust that
is mixed into the abrasive slurry through an abrasion process
performed on the processing target object from staying on the
abrasive pad in an ensured fashion, is more preferable that the
upper limit value is 5 .mu.m or smaller from the viewpoint of
discharging the abrasive slurry from the abrasive pad smoothly to
thereby prevent the temperature of the abrasive pad from increasing
in an ensured fashion, and is most preferable that the upper limit
value is 3 .mu.m or smaller.
[0030] Although a value of (the maximum height roughness (Rz) of
the surface of the abrading part 11)-(the maximum height roughness
(Rz) of the surface of the groove part 12), that is, a difference
between the maximum height roughness (Rz) of the surface of the
abrading part 11 and the maximum height roughness (Rz) of the
surface of the groove part 12 is not particularly limited, it is
preferable that a lower limit value of the difference between the
maximum height roughness (Rz) of the surface of the abrading part
11 and the maximum height roughness (Rz) of the surface of the
groove part 12 is, for example, 20 .mu.m or greater from the
viewpoint of improving the balance between the abrading performance
and the discharging properties of the abrasive slurry, and is
particularly preferable that the lower limit value is 30 .mu.m or
greater. On the other hand, although an upper limit value of the
difference between the maximum height roughness (Rz) of the surface
of the abrading part 11 and the maximum height roughness (Rz) of
the surface of the groove part 12 is not particularly limited to
any value, it is preferable that the upper limit value is 70 .mu.m
or smaller from the viewpoint of facilitating the production of the
resin foam 15, and is particularly preferable that the upper limit
value is 60 .mu.m or smaller.
[0031] Although a value of (the arithmetic mean roughness (Ra) of
the surface of the abrading part 11)-(the arithmetic mean roughness
(Ra) of the surface of the groove part 12), that is, a difference
between the arithmetic mean roughness (Ra) of the surface of the
abrading part 11 and the arithmetic mean roughness (Ra) of the
surface of the groove part 12 is not particularly limited, it is
preferable that a lower limit value of the difference between the
arithmetic mean roughness (Ra) of the surface of the abrading part
11 and the arithmetic mean roughness (Ra) of the surface of the
groove part 12 is, for example, 5 .mu.m or greater from the
viewpoint of improving the balance between the abrading performance
and the discharging properties of the abrasive slurry, and is
particularly preferable that the lower limit value is 10 .mu.m or
greater. On the other hand, although an upper limit value of the
difference between the arithmetic mean roughness (Ra) of the
surface of the abrading part 11 and the arithmetic mean roughness
(Ra) of the surface of the groove part 12 is not particularly
limited to any value, it is preferable that the upper limit value
is 35 .mu.m or smaller from the viewpoint of facilitating the
production of the resin foam 15, and is particularly preferable
that the upper limit value is 30 .mu.m or smaller.
[0032] Although the material of the resin foam 15 is not
particularly limited, the material may be hard resin such as
polyphenylene sulfide resin (PPS resin), polyethylene terephthalate
(PET rein), and polycarbonate resin (PC resin) for example.
[0033] Although the thickness of the resin foam 15 provided on the
abrasive pad 1 is not particularly limited, the thickness may be in
a range of about 0.5 to 2.0 mm for example, and in the abrasive pad
1, the thickness of the resin foam 15 may be about 1.0 mm, for
example. Additionally, although the depth of the groove part 12 is
not particularly limited, the depth may be in a range of about 0.2
to 1.0 mm for example, and in the abrasive pad 1, the depth of the
groove part 12 may be about 0.5 mm, for example.
[0034] The resin foam 15 has a three-dimensional cell structure
that is made up of a plurality of bubbles (cells) that are divided
by bubble walls so that the cells are divided independently of one
another. Although an average bubble diameter is not particularly
limited, it is preferable that the average bubble diameter is, for
example, 4 to 50 .mu.m, and although an average bubble wall
thickness is not particularly limited, it is preferable that the
average bubble wall thickness is, for example, 1 to 5 .mu.m. Here,
the bubble diameter is a diameter when a bubble in an arbitrary
cross section is converted to a circle of the same area, and the
average bubble diameter is an average diameter of 10 bubbles that
are selected arbitrarily. In addition, the bubble wall thickness is
a minimum thickness of a bubble wall between bubbles that lie
adjacent to each other in an arbitrary cross section, and the
average bubble wall thickness is an average of bubble wall
thicknesses at 10 locations that are selected arbitrarily. The
average bubble diameter and the average bubble wall thickness can
be obtained by image processing a photograph of the structure of
the resin foam 15 observed with a scanning electronic microscope
(SEM, made by JEOL Ltd.).
[0035] When the average bubble diameter is smaller than 4 .mu.m,
the number of abrasive grains held in the interior of a bubble is
reduced, and the abrading speed is reduced, whereby a stable
abrasive surface cannot be obtained, whereas when the average
bubble diameter exceeds 50 .mu.m, the strength of the bubble wall
becomes insufficient, and a stable abrading condition cannot be
obtained, which reduces the surface quality and at the same time
causes a large number of abrasive particles to be accumulated
within the bubble, producing secondary particles to facilitate the
generation of a surface defect such as a scratch. The bubble
structure is optimized, and the abrading speed becomes superior by
causing the average bubble diameter to stay within the range
defined therebetween.
[0036] In addition, it is preferable that a ratio of the average
bubble diameter to the average bubble wall thickness is 4 or
greater and 10 or smaller. When the ratio of the average bubble
diameter and the average bubble wall thickness is smaller than 4,
the number of abrasive grains as abrasive particles held in the
interior of the bubble is reduced, whereby the abrading speed is
reduced, and a stable abrasive surface cannot be obtained, whereas
when the ratio of the average bubble diameter and the average
bubble wall thickness exceeds 10, the strength of the bubble wall
becomes insufficient, whereby the stable abrading condition cannot
be obtained, and the abrading speed is reduced.
[0037] Next, an example of a production method of the abrasive pad
1 according to the embodiment of the present disclosure will be
described by reference to the accompanying drawings.
[0038] As illustrated in FIG. 2, in producing the abrasive pad 1, a
resin member 20 having a flat plate-like shape that includes a
surface non-foamed layer 13 in which a surface layer is made up of
a non-foamed part and a foamed part 14 provided in an interior of
the surface non-foamed layer 13 is used. One of flat surfaces where
the surface non-foamed layer 13 is provided constitutes a surface
on an abrading side of the abrasive pad 1. Consequently, an outer
surface of the surface non-foamed layer 13 of the resin member 20
becomes substantially flat. The thickness of the resin member 20 is
the thickness of the resin foam 15 described above, and although
the thickness of the surface non-foamed layer 13 of the resin
member 20 is not particularly limited, the thickness may be in a
range of about 25 to 100 .mu.m for example, and in the resin member
20, the thickness of the surface non-foamed layer 13 may be about
50 .mu.m, for example. The thickness of the foamed part 14 of the
resin member 20 is a thickness resulting from subtracting the
thickness of the surface non-foamed layer 13 on a front surface and
a rear surface of the resin member 20 from the thickness of the
resin member 20.
[0039] Firstly, groove parts 12 are formed on the surface
non-foamed layer 13 of the resin member 20 described above. As a
forming method of the groove part 12, for example, as illustrated
in FIGS. 3A and 3B, a method using a groove part forming die member
21 having blade-like projecting parts 22 may be selected. The
groove part forming die member 21 has a thin plate-like shape.
Although an arrangement of the projecting parts 22 of the groove
part forming die member 21 is not particularly limited, in FIG. 3A,
a plurality of projecting parts 22 are formed concentrically and at
substantially equal intervals. In addition, although a
cross-sectional shape of the projecting part 22 is not particularly
limited, as illustrated in FIG. 3B, in the groove part forming die
member 21, the cross-sectional shape of the projecting part 22 has
a substantially triangular shape.
[0040] The groove part forming die member 21 is pressed against the
resin member 20 in FIG. 2, and apex portions of the projecting
parts 22 of the groove part forming die member 21 are pressed
against the surface non-foamed layer 13 of the resin member 20 at a
predetermined pressure, this allowing the surface non-foamed layer
13 to be pushed towards the foamed part 14, whereby groove parts 12
can be formed on the abrasive pad 1. Consequently, the groove parts
12 are formed on the surface non-foamed layer 13 of the resin
member 20 in positions corresponding to positions of the projecting
parts 22 on the groove part forming die member 21 in FIGS. 3A and
3B. A depth of the groove part 12 is defined according to a height
of the projecting part 22. Consequently, the height of the
projecting part 22 can be selected as required according to a
desired depth of the groove part 12. For example, a range of about
0.2 to 1.0 mm may be selected, and in the groove part forming die
member 21 for producing the abrasive pad 1, the height of the
projecting part 22 may be about 0.5 mm, for example. As a material
for the groove part forming die member 21, the material may be
metal or hard resin, for example.
[0041] As a method for pressing the groove part forming die member
21 against the resin member 20, for example, as illustrated in FIG.
4, the groove part forming die member 21 is given a roller-like
shape, and the projecting parts 22 are pressed against the surface
non-foamed layer 13 of the resin member 20 at the predetermined
pressure while the groove part forming die member 21 having the
roller-like shape is being rotated, whereby the groove parts 12 can
be formed on the resin member 20.
[0042] On the surface on the abrading side of the resin member 20
where the groove parts 12 are formed, locations other than the
groove parts 12 function as the abrading part 11. The foamed parts
14 of the resin member 20 are exposed to function as the abrading
part 11 by removing the surface non-foamed layer 13 at the other
locations than the groove parts 12 through an abrasion process such
as a buff abrasion, whereby the resin member 20 can be formed as
the abrasive pad 1.
[0043] Although a thickness of the resin foam 15 including the
surface non-foamed layer 13 that is removed by the buff abrasion or
the like is not particularly limited, for example, a thickness in
the range of about 50 to 200 .mu.m may be removed, and in the
abrasive pad 1 according to the embodiment, since the thickness of
the surface non-foamed layer 13 of the resin member 20 is about 50
.mu.m, a form results in which about 100 .mu.m is removed from the
resin member 20.
[0044] In the example of the production method of the abrasive pad
1 described above, since the groove parts 12 whose surfaces are
smooth can be formed by pressing the projecting parts 22 having the
blade-like shape against the resin member 20 having the surface
non-foamed layer 13 and the foamed parts 14, the production of the
abrasive pad 1 is easy. In addition, since the groove parts 12 can
be formed by pressing the projecting parts 22 against the resin
member 20, the shape and arrangement of the groove parts 12 can be
changed by changing the shape and arrangement of the projecting
parts 22, thereby making it possible to improve the degree of
freedom in designing the groove parts 12.
[0045] The production method of the resin member 20 having the
surface non-foamed layer 13 and the foamed parts 14 is not
particularly limited, and hence, the known methods can be used. For
example, a method for producing the resin member 20 having the
surface non-foamed layer 13 and the foamed parts 14 may be a method
in which a formed product of predetermined non-foamed resin is
sealed in a high pressure container, and inactive gas is injected
into this high pressure container, whereby the inactive gas is
penetrated into the formed product under pressure. In the method,
after the penetration of the inactive gas into the formed product,
the pressure in the pressure container is released, and then, the
formed product is heated to be foamed, after which the formed
product is cooled, whereby the resin member 20 having the surface
non-foamed layer 13 and the foamed parts 14 is produced.
Alternatively, the foaming characteristics of the individual resin
layers can be controlled to some extent by adding a foaming
nucleating agent to a thermoplastic resin layer for forming a
foamed layer or adding in advance a crystallization nucleating
agent and a crystallization promoting agent to a thermoplastic
resin layer for forming a non-foamed layer. Additionally, the
foaming characteristics can be controlled further strictly by
adopting a specific resin as a thermoplastic resin for use in
forming each layer. The dimension of the bubble 17, the dimension
of the bubble wall 16, and the density at which the bubbles 17 are
provided are controlled by appropriately controlling the foaming
conditions described above, whereby the maximum height roughness
(Rz) and the arithmetic mean roughness (Ra) of the abrading part 11
can be controlled.
[0046] The abrasive pad according to the embodiment of the present
disclosure can be applied, for example, to an abrading device for
abrading a magnetic disc, a semiconductor wafer, various types of
substrates, and electronic materials. As the abrading device, for
example, the abrading device may be one which includes a lower
surface plate on an inner surface of which an abrasive pad is
disposed, a support member for supporting a processing target
object such as a semiconductor wafer on the abrasive pad on the
lower surface plate, an upper surface plate on an inner surface of
which an abrasive pad is disposed for applying a predetermined
pressure to the processing target object such as the semiconductor
wafer, and an abrasive slurry supply unit.
[0047] Next, another embodiment of an abrasive pad of the present
disclosure will be described. In the abrasive pad 1 according to
the embodiment described above, while the foamed parts 14 are
exposed on the overall surface of the abrading part 11 and the
abrading part 11 does not have the surface non-foamed layer 13, in
place of this form, a form may be adopted in which in an abrading
part 11, foamed parts 14 are exposed on a partial surface, and the
other surfaces constitute a surface non-foamed layer 13.
[0048] In the groove part forming die member described above, while
the cross section of the projecting part has the substantially
triangular shape, the cross-sectional shape of the projecting part
is not limited to the shape described as long as the projecting
parts project, and hence, in place of the triangular shape, for
example, a polygonal shape may be used which includes a
quadrangular shape such as a trapezoid, or a pentagonal shape, a
substantially semi-oval shape, a substantially semicircular shape,
and the like.
[0049] Since the abrasive pad of the present disclosure is superior
in the abrading performance and the abrasive slurry discharging
properties, the abrasive pad can be made use of in a variety of
fields, and the abrasive pad of the present disclosure has a high
utilization quality in the field of abrading a magnetic disc and a
semiconductor wafer where a high-degree smoothing mirror surface
work is required.
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