U.S. patent application number 11/691566 was filed with the patent office on 2007-09-27 for polishing pad, method of polishing and polishing apparatus.
This patent application is currently assigned to KABUSHIKI KAISHA TOSHIBA. Invention is credited to Eijiro Koike, Yasutada Nakagawa.
Application Number | 20070224920 11/691566 |
Document ID | / |
Family ID | 38534094 |
Filed Date | 2007-09-27 |
United States Patent
Application |
20070224920 |
Kind Code |
A1 |
Nakagawa; Yasutada ; et
al. |
September 27, 2007 |
POLISHING PAD, METHOD OF POLISHING AND POLISHING APPARATUS
Abstract
A polishing pad according to the invention comprises a pad body
having a polishing surface and a support surface and a plurality of
hole apertures extending from the polishing surface to the support
surface, each of the plurality of apertures having a noncircular
shaped opening oriented at a predetermined angle with respect to a
radial direction of the polishing pad.
Inventors: |
Nakagawa; Yasutada;
(Kanagawa-ken, JP) ; Koike; Eijiro; (Kanagawa-ken,
JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
KABUSHIKI KAISHA TOSHIBA
Tokyo
JP
|
Family ID: |
38534094 |
Appl. No.: |
11/691566 |
Filed: |
March 27, 2007 |
Current U.S.
Class: |
451/41 |
Current CPC
Class: |
B24B 37/26 20130101 |
Class at
Publication: |
451/041 |
International
Class: |
B24B 7/30 20060101
B24B007/30; B24B 1/00 20060101 B24B001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 27, 2006 |
JP |
JP2006-086087 |
Claims
1. A polishing pad for polishing an object, comprising: a pad body
having a polishing surface and a support surface; and a plurality
of hole apertures extending from the polishing surface to the
support surface, each of the plurality of apertures having a
noncircular shaped opening oriented at a predetermined angle with
respect to a radial direction of the polishing pad.
2. The polishing pad according to claim 1, wherein the opening has
an elliptical shape.
3. The polishing pad according to claim 1, wherein the opening
includes a part having a gradually widening width in a
predetermined direction with respect to the radial direction.
4. The polishing pad according to claim 2, wherein the opening has
a major axis thereof angled with respect to the radial
direction.
5. The polishing pad according to claim 3, wherein the opening has
a major axis thereof angled with respect to the radial
direction.
6. The polishing pad according to claim 1, wherein the opening
includes a part having a gradually widening width in a
predetermined direction with respect to the radial direction, the
opening having a down stream side curving inwardly.
7. The polishing pad according to claim 1, wherein the opening
includes a part having a gradually widening width in a
predetermined direction with respect to the radial direction, the
opening having a down stream side curving outwardly.
8. The polishing pad according to claim 6, wherein the opening has
a major axis thereof angled with respect to the radial
direction.
9. The polishing pad according to claim 2, wherein the opening has
a major axis thereof angled with respect to the radial
direction.
10. a polishing pad configured to be arranged to face the
be-polished object hold by the holder mechanism, the polishing pad
including a plate-like pad having a polishing surface and a support
surface; a drive mechanism to rotate the polishing pad; a plurality
of hole apertures extending from the polishing surface to the
support surface, each of the plurality of apertures having a
noncircular shaped opening oriented at a predetermined angle with
respect to a radial direction of the polishing pad.
11. The polishing apparatus according to claim 10, wherein the
opening has an elliptical shape.
12. The polishing apparatus according to claim 10, wherein the
opening includes a part having a gradually widening width in a
predetermined direction with respect to the radial direction.
13. The polishing apparatus according to claim 11, wherein the
opening has a major axis thereof angled with respect to the radial
direction.
14. A method of polishing an object, comprising: holding the
object; and pressing a polishing pad in contact with the object;
the polishing pad including a pad body having a polishing surface
and a support surface; and a plurality of hole apertures extending
from the polishing surface to the support surface, each of the
plurality of apertures having a noncircular shaped opening oriented
at a predetermined angle with respect to a radial direction of the
polishing pad.
15. The polishing method according to claim 14, wherein the opening
has an elliptical shape.
16. The polishing method according to claim 14, wherein the opening
includes a part having a gradually widening width in a
predetermined direction with respect to the radial direction.
17. The polishing method according to claim 16, wherein the opening
has a major axis thereof angled with respect to the radial
direction.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from Japanese Patent Application No. 2006-86087, filed on
Mar. 27, 2006, the entire contents of which are incorporated herein
by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a polishing pad, a method
of polishing and a polishing apparatus for polishing a
semiconductor wafer, which are used for a chemical and mechanical
polishing (CMP) work in a process of manufacturing semiconductor
devices. More particularly, the invention relates to a polishing
pad, method of polishing and a polishing apparatus which facilitate
a feed flow of a slurry liquid to the polishing pad for a
semiconductor wafer.
[0004] 2. Description of the Related Art
[0005] In a process of manufacturing semiconductor devices, a CMP
work is carried out to polish and flatten dielectrics surface of a
wafer. A polishing pad is used for flattening the dielectrics
surface. A polishing surface of the polishing pad for use in the
CMP work is planar. A surface of the wafer to be polished and the
polishing surface of the polishing pad are arranged in parallel to
each other. Thus, the wafer surface and the polishing surface are
arranged in contact with each other and both are rotated for
polishing. Various types of polishing apparatuses are used.
[0006] For example, a polishing pad 100 as shown in FIG. 19 has a
flexible pad 101 and a body pad 102. The body pad 102 is made of a
hard material, foamed urethane, or the like. The body pad 102 has a
number of through holes or apertures, which pass through the body
pad.
[0007] A polishing pad 110 as shown in FIG. 20 has a flexible pad
111, a body pad 112, through holes 113 and lattice like polishing
grooves 114. The grooves supply and remove an abrasive liquid or
slurry and to effectively removes a polishing waste. A polishing
pad 112 having polishing grooves 114 formed therein has a high
ability to supply and remove the abrasive liquid.
[0008] Therefore, such a pad is advantageous in that polishing
amount variations between the central part and the peripheral end
part of the wafer are small. The polishing pad is advantageous in
that it is easy to peel the wafer from the polishing pad since air
can enter between the center of the wafer and the pad through the
grooves.
[0009] Variety shapes of through holes are developed to supply and
remove a slurry and to effectively remove a polishing waste(refer
to, for example, Jpn. Pat. Appln. KOKAI Publication No. 2004-71985
and Jpn. Pat. Appln. KOKAI Publication No. 2003-300149).
[0010] However, this type of polishing pad suffers from the
following problems. A pad body 102 which has only through holes 103
is not easy to bring forward to feed liquid. On the other hand, a
pad body 112 which has only polishing grooves 114 can bring forward
to feed liquid into a wafer. However, the depth of the polishing
grooves 114 is shorter than the depth of through holes 103.
Therefore, the polishing pad with the pad body 112 is short
life.
BRIEF SUMMARY OF THE INVENTION
[0011] It is an object of the present invention to provide a
polishing pad which can polish a wafer evenly with small variations
of polishing amount. It is an object of the present invention to
provide a method of polishing which can polish a wafer evenly with
small variations of polishing amount. It is an object of the
present invention to provide a polishing apparatus which can polish
a wafer evenly with small variations polishing amount. [0012]
(1)According to one embodiment of the present invention, a
polishing pad for polishing an object including a pad body having a
polishing surface and a support surface and a plurality of hole
apertures extending from the polishing surface to the support
surface, each of the plurality of apertures having a noncircular
shaped opening oriented at a predetermined angle with respect to a
radial direction of the polishing pad. [0013] (2) According to
another embodiment of the present invention, a polishing apparatus
for polishing an object including a holder mechanism configured to
hold the object, a polishing pad configured to be arranged to face
the be-polished object hold by the holder mechanism, the polishing
pad including a plate-like pad having a polishing surface and a
support surface, a drive mechanism to rotate the polishing pad a
plurality of hole apertures extending from the polishing surface to
the support surface, each of the plurality of apertures having a
noncircular shaped opening oriented at a predetermined angle with
respect to a radial direction of the polishing pad. [0014] (3)
According to another embodiment of the present invention, a method
of polishing an object including holding the object and pressing a
polishing pad in contact with the object rotating the polishing
pad, the polishing pad including a pad body having a polishing
surface and a support surface and a plurality of hole apertures
extending from the polishing surface to the support surface, each
of the plurality of apertures having a noncircular shaped opening
oriented at a predetermined angle with respect to a radial
direction of the polishing pad.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0015] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate exemplary
embodiments of the invention, and together with the general
description given above and the detailed description of the
embodiments given below, serve to explain the principles of the
invention.
[0016] FIG. 1 is a schematic view of a polishing apparatus having a
polishing pad in accordance with one embodiment of the
invention.
[0017] FIG. 2 is a plan view showing the polishing pad in
accordance with one embodiment of the invention.
[0018] FIG. 3 is a plan view showing through holes of the polishing
pad in accordance with one embodiment of the invention.
[0019] FIG. 4 is a graph showing a relationship between the
polishing rate and the proportion of major axis of the through hole
in accordance with one embodiment of the invention.
[0020] FIG. 5 is a plan view showing a polishing pad in accordance
with another embodiment of the invention.
[0021] FIG. 6 is an explanatory view showing positional relation of
the through hole in FIG. 5
[0022] FIG. 7 is an explanatory view showing relation of polishing
rate in accordance with another embodiment of the invention.
[0023] FIG. 8 is a plan view showing a polishing pad in accordance
with another embodiment of the invention.
[0024] FIG. 9 is an explanatory view showing positional relation of
the through hole in FIG. 8.
[0025] FIG. 10 is an explanatory view showing a relation of
polishing rate and a proportion of major axis to minor axis of the
through hole in accordance with another embodiment of the
invention.
[0026] FIG. 11 is a plan view showing a polishing pad in accordance
with another embodiment of the invention.
[0027] FIG. 12 is a plan view showing a polishing pad in accordance
with another embodiment of the invention.
[0028] FIG. 13 is an explanatory view showing positional relation
of a through hole and a central of the polishing pad in accordance
with another embodiment of the invention.
[0029] FIG. 14 is an explanatory view showing relation of polishing
rate and angle in accordance with another embodiment of the
invention.
[0030] FIG. 15 is a plan view showing a polishing pad in accordance
with another embodiment of the invention.
[0031] FIG. 16 is a plan view showing a polishing pad in accordance
with another embodiment of the invention.
[0032] FIG. 17 is an explanatory view showing positional relation
of a through hole and a central of the polishing pad in accordance
with another embodiment of the invention.
[0033] FIG. 18 is a plan view showing a polishing pad in accordance
with another embodiment of the invention.
[0034] FIG. 19 is a cross sectional view showing a polishing
pad.
[0035] FIG. 20 is a cross sectional view showing a polishing
pad.
DETAILED DESCRIPTION OF THE INVENTION
[0036] FIG. 1 is a structural view showing a polishing apparatus
100 set up a polishing pad 10, which is a first embodiment of the
present invention. FIG. 2 is a plan view showing the polishing pad
10. FIG. 3 is a plan view showing through holes 20 which is
provided on the polishing pad 10. X is a rotating center on the
polishing pad 10, F is a flowing direction of abrasive liquid and P
is a rotating direction of the polishing pad 10.
[0037] The polishing apparatus 100 has the polishing pad 10, a
holder mechanism 110 providing a wafer w and a rotary drive
mechanism 120 which rotates the polishing pad 10, as shown in FIG.
1.
[0038] The polishing pad 10 is laminated with a soft pad 11 and a
pad body 12. The pad body 12 is made of hard resin such as formed
polyurethane or urethane.
[0039] The pad body 12 is provided with the through holes 20. The
through holes 20 are provided from a polishing surface 12a to a
support surface 12b, in other words, in the thickness direction of
the pad body 12. The through holes 20 formed by such as a punching
process or a nesting block.
[0040] A predetermined number of the through holes 20 are provided
in approximately a concentric fashion on the polishing body 12, as
shown in the embodiment illustrated in FIG. 2. The through holes 20
is provided in approximately a concentric fashion with respect to
the rotating center X on the polishing pad 10 when a to-be-polished
object is polished, too. The through holes 20 are noncircular
shaped openings. The through holes 20 are provided in a
predetermined angle with respect to a radial direction. It is
better that all of the through holes 20 are provided in the same
predetermined angle. However, if there is a positive effect, all of
the through holes 20 don't need to be same angle.
[0041] The through holes 20 may be elliptical, as shown in FIG. 3.
The elliptical shape of the holes has a minor axis a and a major
axis b. The rotating center X is provided on a line extending from
the minor axis.
[0042] In one embodiment, the through holes 20 may be provided at
1-10 per 1 cm2. One of a dimension of the through holes 20 is 1-6
mm2. A surface ratio of the through holes 20 with respect to the
surface area of the pad body 12 may be 1-60 percent.
[0043] The through holes 20 are provided along a line on which the
abrasive liquid flows or travels. It is easy to flow out abrasive
liquid which is in the through holes 20. As a result, it promotes
to feed and exhaust the abrasive liquid, and a polishing rate
rises. And a life of the polishing pad 10 does not change compared
with a life of using only prior through holes.
[0044] A polishing rate rises to increase b/a (a rate of major axis
for a minor axis), as shown in FIG. 4. For example, in case of
b/a=1.2, a polishing rate rises about 10 percent compared with
prior through holes (b/a=1).
[0045] According to the embodiment of the polishing pad 10, it can
promote to feed and exhaust the abrasive liquid. And the polishing
rate can rise.
[0046] FIG. 5 is a plan view showing a polishing pad 10A which is a
second embodiment of the present invention. FIG. 6 is a showing
relationship between the through holes 20 and the rotating center
X. In FIG. 5 and FIG. 6, the same functional parts showing in FIG.
2 and FIG. 3 are given the same number and overlapping explanation
is skipped.
[0047] For the polishing pad 10A, which is one embodiment of the
present invention, the major axis of the through holes 20 is
provided at a predetermined angle .theta. with respect to the
radial direction R. The through holes 20 can promote to feed and
exhaust the abrasive liquid with centrifugal force.
[0048] FIG. 7 shows a change in polishing rate when angle .theta.
is changed from 0 degree to 90 degree. When angle .theta. is 90
degree in FIG. 2, the minor direction is accorded with the diameter
direction R. When angle .theta. is from 40 degree to 80 degree, the
polishing rate is maximum. The maximum polishing rate is twice as
the polishing rate in FIG. 2. Angle .theta. of the maximum
polishing rate change according to rotary speed of a polishing
pad.
[0049] The polishing pad 10A can promote to feed and exhaust the
abrasive liquid and improve the polishing rate.
[0050] FIG. 8 is a plan view showing a polishing pad 10B which is a
third embodiment of the present invention. FIG. 9 shows
relationship between the through holes 30 and the rotating center X
of the polishing pad 10B. In FIG. 8 and FIG. 9, the same functional
parts showing in FIG. 2 and FIG. 3 are given the same number and
overlapping explanation is skipped.
[0051] On the polishing pad 10B of the embodiment of the present
invention, the through holes 30 are provided. The through holes 30
are teardrop shape which shape is wider down stream area than up
stream side.
[0052] A polishing rate rises to increase d/c (a rate of major axis
for a minor axis), as shown in FIG. 10. For example, in case of
d/c=1.2, a polishing rate rises about 5 percent compared with prior
through holes (b/a=1).
[0053] FIG. 11 is a plan view showing a polishing pad 10C which is
a forth embodiment of the present invention. In FIG. 11, the same
functional parts showing in FIG. 8 are given the same number and
overlapping explanation is skipped.
[0054] On the polishing pad 10C of the embodiment of the present
invention, a down stream side of the through holes 30 is angled
outwardly, away from the center of the pad. In this arrangement,
the through holes 30 can promote to supply and drain the abrasive
liquid by a centrifugal force.
[0055] FIG. 12 is a plan view showing a polishing pad 10D which is
a fifth embodiment of the present invention. FIG. 13 shows
relationship between the through holes 40 and the rotating center X
of the polishing pad 10B. In FIG. 12 and FIG. 13, the same
functional parts showing in FIG. 2 and FIG. 3 are given the same
number and overlapping explanation is skipped.
[0056] On the polishing pad 10D of the embodiment of the present
invention, through holes 40 are provided. The through holes 40 are
teardrop shape which shape is gradually wider down stream area than
up stream side. Down stream area of through holes 40 are provided
to be leaned .phi. degree to inner circumference configuration.
[0057] As shown in FIG. 14, a polishing rate rises to adjust .phi.
degree. For example, when .phi. is provided more than 20 degree, a
polishing rate rises about 5 percent compared with through holes 30
which are teardrop shape.
[0058] FIG. 15 is a plan view showing a polishing pad 10E which is
a sixth embodiment of the present invention. In FIG. 15, the same
functional parts showing in FIG. 12 are given the same number and
overlapping explanation is skipped.
[0059] On the polishing pad 10E of the embodiment of the present
invention, the through holes 40 are provided to be leaned for
circumferential direction. In other words, a down stream area of
the abrasive liquid, a side of the through holes 30 provided to be
out side direction on the polishing pad 10E.
[0060] The through holes 40 can nurture to feed and exhaust the
abrasive liquid with centrifugal force.
[0061] FIG. 16 is a plan view showing a polishing pad 10F which is
a seventh embodiment of the present invention. FIG. 17 is a showing
relationship between the through holes 50 and the rotating center X
of the polishing pad 10B.
[0062] In FIG. 16 and FIG. 17, the same reference numeral as in
FIG. 2 and 3 are used for the same functional parts, and their
explanations are omitted.
[0063] On the polishing pad 10F of the embodiment of the present
invention, the through holes 50 are provided. The through holes 50
are teardrop shape having a down stream area gradually wider than
an up stream side. Down stream area of through holes 50 is angled
outwardly at .phi. degree with respect to the up stream side. Outer
configuration is defined as below zero.
[0064] A polishing rate rises to adjust .phi. degree. For example,
when .phi. is provided more than -20 degree, a polishing rate rises
about 5 percent compared with through holes 30 which are teardrop
shape.
[0065] FIG. 18 is a plan view showing a polishing pad 10G which is
a eighth embodiment of the present invention.
[0066] In FIG. 18, the same functional parts showing in FIG. 16 are
given the same number and overlapping explanation is skipped.
[0067] In one embodiment, for the polishing pad 10G, the through
holes 50 are provided to be leaned for circumferential direction.
In other words, the through holes 50 are provided to be leaned to
out side direction on down stream area of the abrasive liquid. The
through holes 50 can nurture to feed and exhaust the abrasive
liquid with centrifugal force.
[0068] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
* * * * *