U.S. patent application number 11/727300 was filed with the patent office on 2007-09-27 for polishing pad, chemical mechanical polishing apparatus and method for manufacturing polishing pad.
This patent application is currently assigned to NEC ELECTRONICS CORPORATION. Invention is credited to Masafumi Shiratani.
Application Number | 20070224923 11/727300 |
Document ID | / |
Family ID | 38534095 |
Filed Date | 2007-09-27 |
United States Patent
Application |
20070224923 |
Kind Code |
A1 |
Shiratani; Masafumi |
September 27, 2007 |
Polishing pad, chemical mechanical polishing apparatus and method
for manufacturing polishing pad
Abstract
A polishing pad with reduced cost and easy manufacturability
without waste is provided. A disc-shaped polishing layer 31 having
a plurality of through holes 34 formed therein, an adhesive layer
33 provided only in a position in a back surface of the polishing
layer 31 where no through hole 34 is formed and a disc-shaped
support plate 32 having a flat surface, which is joined to the back
surface of the polishing layer 31 by the adhesive layer 33 are
provided. Since an adhesive layer 33 is not exposed to bottoms of
the through holes 34 of the polishing layer 31, acting the slurry
over the adhesive layer 33 to strip the polishing layer 31 from the
support plate 32 is inhibited. Since the through holes 34 formed in
the polishing layer 31 do not extend to the support plate 32, a
decrease in the mechanical strength is not caused.
Inventors: |
Shiratani; Masafumi;
(Kanagawa, JP) |
Correspondence
Address: |
YOUNG & THOMPSON
745 SOUTH 23RD STREET, 2ND FLOOR
ARLINGTON
VA
22202
US
|
Assignee: |
NEC ELECTRONICS CORPORATION
KANAGAWA
JP
|
Family ID: |
38534095 |
Appl. No.: |
11/727300 |
Filed: |
March 26, 2007 |
Current U.S.
Class: |
451/56 ; 451/285;
451/533 |
Current CPC
Class: |
B24D 11/001 20130101;
B24B 37/26 20130101 |
Class at
Publication: |
451/56 ; 451/285;
451/533 |
International
Class: |
B24B 1/00 20060101
B24B001/00; B24B 29/00 20060101 B24B029/00; B24D 11/00 20060101
B24D011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 27, 2006 |
JP |
2006-085312 |
Claims
1. A polishing pad having a multiple-layered structure and being
utilized in a chemical mechanical polishing (CMP) process,
comprising: a disc-shaped polishing layer having a plurality of
through holes formed to extend from a front surface to a back
surface thereof; an adhesive layer provided only in a position in a
back surface of said polishing layer where said through hole is not
formed; and a disc-shaped support plate having a flat surface,
which is joined to said back surface of the polishing layer by said
adhesive layer.
2. The polishing pad according to claim 1, wherein a surface of
said support plate is exposed in a bottom of said through hole in
said polishing layer without disposing said adhesive layer
thereon.
3. A chemical mechanical polishing (CMP) apparatus for performing a
CMP process for a workpiece with a polishing pad, comprising: the
polishing pad as set forth in claim 1; a disc-shaped platen having
a front surface, which is joined to a back surface of said
polishing pad; a pad actuating unit for actuating a rotation of
said platen that is provided with said polishing pad; a slurry
supplying unit for supplying a slurry to said polishing pad that is
actuated to be rotated; and a workpiece pressing unit for
supporting said workpiece and pressing said workpiece to said
polishing pad that is actuated to be rotated.
4. A chemical mechanical polishing (CMP) apparatus for performing a
CMP process for a workpiece with a polishing pad, comprising: the
polishing pad as set forth in claim 2; a disc-shaped platen having
a front surface, which is joined to a back surface of said
polishing pad; a pad actuating unit for actuating a rotation of
said platen that is provided with said polishing pad; a slurry
supplying unit for supplying a slurry to said polishing pad that is
actuated to be rotated; and a workpiece pressing unit for
supporting said workpiece and pressing said workpiece to said
polishing pad that is actuated to be rotated.
5. A method for manufacturing a polishing pad, which has a
multiple-layered structure and is utilized in a chemical mechanical
polishing (CMP) process, including: providing an adhesive layer and
a stripping form on a back surface of a disc-shaped polishing layer
having a front surface serving as a polishing surface; forming a
plurality of through holes, which extend from a surface of said
polishing layer through said adhesive layer to a back surface of
said stripping form; stripping said stripping form from the back
surface of said polishing layer having said plurality of through
holes formed therein; and joining the back surface of said
polishing layer exposed by stripping said stripping form to a
surface of a support plate by said adhesive layer.
6. The method for manufacturing the polishing pad according to
claim 5, further comprising preparing a two-sided tape having a
structure including an adhesive layer and stripping forms affixed
to both sides of the adhesive layer, wherein said providing the
adhesive layer and the stripping form on the back surface of the
disc-shaped polishing layer includes providing an exposed adhesive
layer of said two-sided tape onto a back surface of the polishing
layer, said exposed adhesive layer of the two-sided tape being
exposed by stripping only said stripping form disposed on the front
surface of said two-sided tape.
7. The method for manufacturing the polishing pad according to
claim 5, wherein said providing the adhesive layer and the
stripping form on the back surface of the disc-shaped polishing
layer includes pasting said stripping form after said adhesive
layer is provided with the back surface of said polishing layer by
an application of an adhesive agent.
Description
[0001] This application is based on Japanese patent application No.
2006-85,312, the content of which is incorporated hereinto by
reference.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to a polishing pad utilized in
a chemical mechanical polishing (CMP) process, and particularly
relates to a polishing pad having a multiple-layered structure, in
which a support plate is joined to a polishing layer having a
plurality of through holes formed therein, a CMP apparatus having
such polishing pad and a method for manufacturing such polishing
pad.
[0004] 2. Related Art
[0005] Currently, in processes for manufacturing semiconductor
devices, a chemical mechanical polishing (CMP) process may be often
performed for providing finer planarized surfaces. In such CMP
process, a disc-shaped polishing pad is supported by a shaft, and
is driven to be rotated, while a slurry is supplied to such
polishing pad that is driven to be rotated. A workpiece is
compressing-contacted with the surface of the polishing pad in such
condition to planarize the surface of the workpiece.
[0006] Better retaining-ability of a slurry is required for the
polishing pad utilized in such CMP process. Thus, as shown in FIG.
4 and FIG. 5, an approach of providing a polishing pad 10 having a
multiple-layered structure of a support plate 12 and a polishing
layer 11, surface of which is provided with a large number of
through holes 13 formed therein. In such polishing pad 10, the
polishing layer 11 is joined to the support plate 12 by an adhesive
layer 14.
[0007] Here, a first conventional example of a method for
manufacturing a polishing pad 10 is described as follows in
reference to FIGS. 6A to 6D. First of all, a disc-shaped polishing
layer 11 is prepared as shown in FIG. 6A, and through holes 13 are
formed in such polishing layer 11 by a punching processing as shown
in FIG. 6B.
[0008] Then, as shown in FIG. 6C, a disc-shaped support plate 12 is
prepared, and an adhesive layer 14 is provided over the surface
thereof. The adhesive layer 14 may be formed by, for example, an
application of an adhesive agent, or pasting tapes on both sides
thereof. Then, as shown in FIG. 6D, a back surface of the polishing
layer 11 is joined to a surface of the support plate 12 by the
adhesive layer 14 to provide a finished product of the polishing
pad 10 (see, for example, Japanese Patent Laid-Open No. H09-117,855
(1997)).
[0009] In addition, a second conventional example of a method for
manufacturing a polishing pad is described as follows in reference
to FIGS. 7A to 7D. First of all, a disc-shaped polishing layer 21
is prepared as shown in FIG. 7A, and a disc-shaped support plate 22
is prepared, as shown in FIG. 7B.
[0010] Next, as shown in FIG. 7C, the polishing layer 21 is joined
to the support plate 22 by an adhesive layer 24. Then, as shown in
FIG. 7D, through holes 23 extending through the polishing layer 21
from the surface thereof are formed to provide a finished product
of the polishing pad 20 (see, for example, Japanese Patent
Laid-Open No. H11-156,699 (1999)).
[0011] In addition to above, through holes 13 and 23 of the
polishing layer 11 and 21 as described above may be formed as
circular small holes as shown in FIG. 4, or may be formed as linear
concave trenches (not shown).
[0012] In the polishing pad 10 produced by the above described
first method for manufacturing the polishing pad, as shown in FIG.
5 and FIG. 6D, an adhesive layer 14 is partially exposed in the
bottom of the through holes 13. Thus, the slurry acts on the
adhesive layer 14 and degrades the adhesive strength such that the
polishing layer 11 is easily flaked off from the support plate 12.
Further, if the flaked adhesive layer 14 is mixed into the slurry,
a failure is caused in the workpiece.
[0013] On the other hand, in the polishing pad 20 produced by the
above-described second method for manufacturing the polishing pad,
it is difficult to form the through holes 23 only in the polishing
layer 21. Thus, as shown in FIG. 7D, the through holes 23 are
necessarily formed so as to reach to the support plate 22,
providing a deteriorated mechanical strength of the polishing pad
20.
[0014] In addition, as shown in FIG. 7C, through holes 23 are not
yet formed at the time the support plate 22 is joined to the
polishing layer 21. Thus, it is impossible to eliminate air trapped
in the adhesive layer 24 through the through hole 23 while joining
the polishing layer 21 to the support plate 22. This leads joining
the polishing layer 21 to the support plate 22 while air is
remained in the adhesive layer 24, providing a reduced bonding
strength.
SUMMARY OF THE INVENTION
[0015] According to one aspect of the present invention, there is
provided a polishing pad having a multiple-layered structure and
being utilized in a chemical mechanical polishing (CMP) process,
comprising: a disc-shaped polishing layer having a plurality of
through holes formed to extend from a front surface to a back
surface thereof; an adhesive layer provided only in a position in a
back surface of the polishing layer where the through hole is not
formed; and a disc-shaped support plate having a flat surface,
which is joined to the back surface of the polishing layer by the
adhesive layer.
[0016] Since an adhesive layer is not exposed to the bottoms of the
through holes of the polishing layer, the degradation of the
adhesive strength by the slurry is inhibited. And since the through
holes formed in the polishing layer do not extend to the support
plate, a decrease in the mechanical strength is not caused.
[0017] According to another aspect of the present invention, there
is provided a chemical mechanical polishing (CMP) apparatus for
performing a CMP process applied to a workpiece utilizing a
polishing pad, comprising: a polishing pad according to the present
invention; a disc-shaped platen having a front surface, which is
joined to a back surface of the polishing pad; a pad actuating unit
for rotating the polishing pad joined on the platen; a slurry
supplying unit for supplying a slurry to the polishing pad that is
actuated to be rotated; and a workpiece pressing unit for
supporting the workpiece and pressing the workpiece to the
polishing pad that is actuated to be rotated. Thus, since the CMP
apparatus of the present invention is capable of polishing a
workpiece utilizing the polishing pad according to the present
invention, acting the slurry over the adhesive layer of the
polishing pad and the degradation of the adhesive strength by the
slurry is inhibited.
[0018] According to further aspect of the present invention, there
is provided a method for manufacturing a polishing pad, which is
utilized in a chemical mechanical polishing (CMP) process,
including: providing an adhesive layer and a stripping form on a
back surface of a disc-shaped polishing layer having a front
surface serving as a polishing surface; forming a plurality of
through holes, which extend from a surface of the polishing layer
through the adhesive layer to a back surface of the stripping form;
stripping the stripping form from the back surface of the polishing
layer having the plurality of through holes formed therein; and
joining the back surface of the polishing layer exposed by
stripping the stripping form to a surface of a support plate by the
adhesive layer.
[0019] Since the polishing pad is produced to have a structure that
prevents exposing the adhesive layer in the bottoms of the through
holes of the polishing layer in the method for manufacturing the
polishing pad of the present invention, the polishing pad that
prevents acting the slurry over the adhesive layer of the polishing
pad is produced, and since the through holes formed in the
polishing layer do not reach to the support plate, the polishing
pad having an improved mechanical strength is produced.
[0020] In addition to above, the term "flat surface" appeared in
claims and the description of the present invention means a surface
that is physically formed for the aim of creating a flat surface,
and of course it is necessary to be a geometric completely flat
plane.
[0021] Since an adhesive layer is not exposed to bottoms of through
holes of the polishing layer, acting the slurry over the adhesive
layer and the degradation of the adhesive strength by the slurry is
inhibited, so that a peeling off of the polishing layer from the
support plate can be prevented. And since through holes formed in
the polishing layer do not extend to the support plate, a decrease
in the mechanical strength is prevented, so that an improved
polishing of the workpiece can be presented.
[0022] Since the CMP apparatus of the present invention is capable
of polishing a workpiece utilizing the polishing pad according to
the present invention, acting the slurry over the adhesive layer of
the polishing pad and the degradation of the adhesive strength by
the slurry is inhibited, so that an improved polishing of the
workpiece can be presented without causing a peeling off of the
polishing layer from the support plate.
[0023] Since the polishing pad can be produced to have a structure
that prevents exposing the adhesive layer in the bottoms of the
through holes of the polishing layer in the method for
manufacturing the polishing pad of the present invention, there can
produce the polishing pad that prevents acting the slurry over the
adhesive layer of the polishing pad and the degradation of the
adhesive strength by the slurry. And since the through holes formed
in the polishing layer do not reach to the support plate, the
polishing pad having an improved mechanical strength can be
produced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The above and other objects, advantages and features of the
present invention will be more apparent from the following
description taken in conjunction with the accompanying drawings, in
which:
[0025] FIG. 1 is a schematic vertical cross-sectional view, showing
a structure of a main part of a polishing pad in an embodiment of
the present invention;
[0026] FIGS. 2A to 2E are a schematic vertical cross-sectional
views, illustrating operations of a method for manufacturing the
polishing pad according to the present invention;
[0027] FIG. 3A is a schematic side view, showing a condition of
mounting a polishing pad of the present embodiment onto a platen of
a CMP apparatus, and FIG. 3B is a schematic side view, showing a
condition of mounting a conventional polishing pad onto a platen of
a CMP apparatus;
[0028] FIG. 4 is a plan view, showing an appearance of a
conventional polishing pad;
[0029] FIG. 5 is a schematic vertical cross-section view, showing a
structure of a main part of a conventional polishing pad;
[0030] FIGS. 6A to 6D are vertical cross-section views,
illustrating operations of a first conventional method for
manufacturing a conventional polishing pad; and
[0031] FIGS. 7A to 7D are vertical cross-section views,
illustrating operations of a second conventional method for
manufacturing a conventional polishing pad.
DETAILED DESCRIPTION
[0032] The invention will be now described herein with reference to
illustrative embodiments. Those skilled in the art will recognize
that many alternative embodiments can be accomplished using the
teachings of the present invention and that the invention is not
limited to the embodiments illustrated for explanatory
purposed.
[0033] Preferable embodiments of the present invention will be
described as follows in further detail, in reference to FIG. 1,
FIGS. 2A to 2E and FIGS. 3A and 3B. In all figures, identical
numeral is assigned to an element commonly appeared in both of the
description of the present invention the description of the related
art, and the detailed description thereof will not be repeated.
[0034] A polishing pad 30 of the present embodiment is formed to
have a dual-layer structure, which is one of typical
multiple-layered structure. Thus, as shown in FIG. 1, a disc-shaped
support plate 32 is joined to a disc-shaped polishing layer 31 by
an adhesive layer 33.
[0035] A plurality of through holes 34 composed of circular small
holes are formed to extend from a front surface to a back surface
of the polishing layer 31. The adhesive layer 33 is provided on the
back surface of the polishing layer 31 only in a position where no
through hole 34 is formed.
[0036] Now, a method for manufacturing the polishing pad 30 of the
present embodiment will be described in reference to FIGS. 2A to
2E. First of all, the disc-shaped polishing layer 31 is prepared as
shown in FIG. 2A, and the adhesive layer 33 and a stripping form 36
are provided on the back surface thereof as shown in FIG. 2B.
[0037] More specifically, a two-sided tape (not shown) having the
adhesive layer 33, which is provided with stripping forms 36
affixed on both sides thereof, is prepared. Only a stripping form
36 in the side of the front surface of the two-sided tape is
stripped to expose the adhesive layer 33.
[0038] The front surface of such adhesive layer 33 is pasted on the
back surface of the polishing layer 31, so that the adhesive layer
33 and the stripping form 36 are provided on the polishing layer
31. In such condition, as shown in FIG. 2C, a plurality of through
holes 34 are formed in the polishing layer 31, the adhesive layer
33 and the stripping form 36.
[0039] In next, as shown in FIG. 2D, the stripping form 36 is
stripped from the back surface of the polishing layer 31, which is
provided with a plurality of through holes 34 formed therein. Then,
as shown in FIG. 2E, a front surface of the support plate 32 is
joined to the back surface of polishing layer 31 exposed by
stripping the stripping form 36 by the adhesive layer 33 to
complete the manufacture of the polishing pad 30.
[0040] The polishing pad 30 produced by the method for
manufacturing the polishing pad as described above is utilized in a
CMP process for workpieces as a part of the CMP apparatus 40, as
shown in FIG. 3A. Such CMP apparatus 40 includes, for example, a
platen 41, a pad actuating unit 42, a slurry supplying unit 43, a
workpiece pressing unit (not shown) and the like.
[0041] The platen 41 is formed to have a disc-shape, which is the
same as the two-dimensional geometry of the polishing pad 30. The
polishing pad 30 is mounted in a replaceable manner on the front
surface of the platen 41 by an adhesive agent or a two-sided tape.
The pad actuating unit 42 actuates a rotation of the platen 41 to
rotate the polishing pad 30 that is joined on the surface
thereof.
[0042] The slurry supplying unit 43 supplies a slurry S to the
rotating polishing pad 30. The workpiece pressing unit functions as
supporting the workpiece and compressing-contacting thereof with
the rotating polishing pad 30. In the CMP apparatus 40 having such
structure, the workpiece can be CMP processed utilizing the
polishing pad 30.
[0043] In the polishing pad 30 produced by the method for
manufacturing the polishing pad of the present embodiment, as shown
in FIG. 2E and FIG. 1, an exposure of the adhesive layer 33 in the
bottoms of the through holes 34 is prevented. Thus, unwanted
peeling-off of the polishing layer 31 from the support plate 32 due
to acting of the slurry S over the adhesive layer 33 can be
sufficiently prevented.
[0044] Further, a failure of a workpiece due to a contamination of
the flaked adhesive layer 33 into the slurry S can be sufficiently
prevented. In addition, since the through holes 34 are not formed
to extend to the support plate 32, a decrease in the mechanical
strength thereof can also be prevented.
[0045] Moreover, in the method for manufacturing the polishing pad
according to the present embodiment, as shown in FIG. 2C to FIG.
2E, the through holes 34 are formed at the time when the polishing
layer 31 is joining to the support plate 32. Air trapped in the
adhesive layer 33 can be removed via the through holes 34, while
the polishing layer 31 is joining to the support plate 32.
Therefore, the polishing layer 31 can be joined to the support
plate 32 without remained air in the adhesive layer 33, thereby
ensuring an improved bonding strength therebetween.
[0046] In addition, in the method for manufacturing the polishing
pad of the present embodiment, the through holes 34 are formed,
after the adhesive layer 33 and the stripping form 36 on the back
surface of the polishing layer 31 are provided, as described above.
Thus, handling of the polishing layer 31 having the adhesive layer
33 provided thereon is facilitated. In addition, a contamination of
the adhesive layer 33 is avoided.
[0047] Therefore, the polishing pad 30 containing no defect in the
adhesive layer 33 can be easily manufactured.
[0048] Japanese Patent Laid-Open No. 2001-219,362 discloses a
structure of a polishing pad 50 having a single layer structure and
a technique for joining the polishing pad 50 to a platen 41, as
shown in FIG. 3B. The polishing pad 50 includes a plurality of
through holes 51 formed to extend from a front surface to a back
surface thereof.
[0049] More specifically, in the polishing pad 50, an adhesive
layer 52 is provided on the back surface only in a position where
no through hole 51 is formed. Such polishing pad 50, in turn, is
joined to the platen 41 by the adhesive layer 52.
[0050] However, this is the technique for joining the polishing pad
50 of the single layer structure to the platen 41, and it is
difficult to simply apply such technique for the single layer
structure to the technique for joining the polishing layer 31 of
the polishing pad 30 having the multiple-layered structure to
support plate 32.
[0051] Japanese Patent Laid-Open No. 2001-219,362 also discloses
that the adhesive layer 52 is formed by employing an adhesive agent
or a two-sided tape. When the adhesive layer 52 is formed by
employing an adhesive agent, through holes 51 are formed in the
polishing pad 50 coated with an adhesive agent over the back
surface thereof.
[0052] However, this leads to handling the polishing pad 50 under
the condition, in which the adhesive agent coated thereon is
exposed, and thus the handling thereof is difficult and a
contamination may be possibly caused in the adhesive agent.
[0053] It is not intended that the present invention is limited to
the configurations illustrated in the above-described embodiment,
and various modifications thereof are available. For example, while
it is assumed that the through holes 34 of the polishing layer 31
are circular small holes in the above-described configuration, such
through holes 34 may alternatively be formed to have variety of
geometries (not shown) such as cross-shaped heteromorphy holes,
linear concave trenches and the like.
[0054] Further, the configuration of simultaneously providing the
adhesive layer 33 and the stripping form 36 on the polishing layer
31 by pasting the adhesive layer 33 of the two-sided tape, in which
only one stripping form in one side is stripped, on the polishing
layer 31 is illustrated in the above-described configuration.
[0055] Alternatively to above, after the adhesive agent is applied
on the back surface of the polishing layer 31 to form the adhesive
layer 33, the stripping form 36 may be pasted thereon. In this
case, though the adhesive layer 33 is formed of an adhesive agent,
easier handling of polishing layer 31 is provided and a
contamination in the adhesive agent is avoided.
[0056] It is apparent that the present invention is not limited to
the above embodiment, and may be modified and changed without
departing from the scope and spirit of the invention.
* * * * *