U.S. patent application number 11/537162 was filed with the patent office on 2007-04-05 for polishing pad and polishing apparatus.
Invention is credited to Masaomi NAKAHATA.
Application Number | 20070077867 11/537162 |
Document ID | / |
Family ID | 37964661 |
Filed Date | 2007-04-05 |
United States Patent
Application |
20070077867 |
Kind Code |
A1 |
NAKAHATA; Masaomi |
April 5, 2007 |
POLISHING PAD AND POLISHING APPARATUS
Abstract
A polishing pad according to the invention includes a plate-like
pad body having one surface serving as a polishing surface and the
other surface serving as a support surface, and a plurality of hole
parts which extend from the polishing surface to the support
surface, the each hole part containing a plurality of elongated
holes that extend in different directions on a plane of the
polishing surface.
Inventors: |
NAKAHATA; Masaomi;
(Yokohama-shi, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Family ID: |
37964661 |
Appl. No.: |
11/537162 |
Filed: |
September 29, 2006 |
Current U.S.
Class: |
451/41 ;
451/527 |
Current CPC
Class: |
B24B 37/26 20130101 |
Class at
Publication: |
451/041 ;
451/527 |
International
Class: |
B24B 7/30 20060101
B24B007/30; B24D 11/00 20060101 B24D011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 3, 2005 |
JP |
2005-290313 |
Claims
1. A polishing pad which polishes a to-be-polished object,
comprising: a plate-like pad body having one surface serving as a
polishing surface and the other surface serving as a support
surface; and a plurality of hole parts configure to extend from the
polishing surface to the support surface, said each hole part
containing a plurality of elongated holes that extend in different
directions on a plane of the polishing surface.
2. The polishing pad according to claim 1, wherein the elongated
holes of said each hole part radially extend from a predetermined
position.
3. The polishing pad according to claim 2, wherein the elongated
hole is plural in number.
4. The polishing pad according to claim 2, wherein the elongated
hole takes a cross-shape.
5. The polishing pad according to claim 2, wherein a shape of the
elongated hole includes a linear shape.
6. The polishing pad according to claim 2, wherein a shape of the
elongated hole includes a curve shape.
7. The polishing pad according to claim 1, wherein the hole parts
are arrayed at equal intervals.
8. The polishing pad according to claim 1, wherein the support
surface of the pad body is provided with a communicating hole which
communicates the adjacent hole parts with each other.
9. A polishing apparatus comprising: a plate-like polishing pad
provided on a surface plate, the polishing pad having one surface
serving as a polishing surface and the other surface serving as a
support surface attached to the surface plate, and the pad body
including a plurality of hole parts configure to extend from the
polishing surface to the support surface, said each hole part
containing a plurality of elongated holes that extend in different
directions on a plane of the polishing surface; a holder member
arranged to face the polishing pad, the holder member holding a
to-be-polished object; and a drive mechanism configure to polish
the to-be-polished object by relatively and frictionally moving the
polishing pad and the to-be-polished object held by the holder
member.
10. The polishing apparatus according to claim 9, wherein the drive
mechanism relatively moves the to-be-polished object and the holder
member in a friction manner such that they are separated from a
part on the peripheral part of the polishing surface where some of
the hole parts are exposed.
11. The polishing apparatus according to claim 9, wherein the
elongated holes of said each hole part radially extend from a
predetermined position.
12. The polishing apparatus according to claim 9, wherein the
support surface of the pad body is provided with a communicating
means which communicates the adjacent hole parts with each
other.
13. A method of polishing a to-be-polishing surface of a
to-be-polished object, comprising: holding a plate-like polishing
pad provided on a surface plate, the polishing pad having one
surface serving as a polishing surface and the other surface
serving as a support surface attached to the surface plate, and the
pad body including a plurality of hole parts which extend from the
polishing surface to the support surface, said each hole part
containing a plurality of elongated holes that extend in different
directions on a plane of the polishing surface; holding a
to-be-polished object by a holder member such that the
to-be-polished object is arranged to face the polishing pad; and
moving the polishing pad relative to the to-be-polished object in a
friction manner.
14. The polishing method according to claim 13, wherein the
to-be-polished object and the holder member are relatively moved in
a friction manner such that, while being separated from a part on
the peripheral part of the polishing surface where some of the hole
parts are exposed.
15. The polishing method according to claim 13, wherein the
elongated holes of said each hole part radially extend from a
predetermined position.
16. The polishing method according to claim 13, wherein the support
surface of the pad body is provided with a communicating hole which
communicates the adjacent hole parts with each other.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from prior Japanese Patent Application No. 2005-290313,
field Oct. 3, 2005, 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 and a
polishing apparatus for polishing a semiconductor wafer, which are
used for a chemical and mechanical polishing work in a process of
manufacturing semiconductor devices. More particularly, the
invention relates to a polishing pad and a polishing apparatus
which enable the polishing pad to be elongated and are capable of
polishing a semiconductor wafer precisely flat.
[0004] 2. Description of the Related Art
[0005] In a process of manufacturing semiconductor devices, a
chemical and mechanical polishing work is carried out when an
insulating film surface of a wafer is flattened. A polishing pad is
used for flattening of the insulating film surface. A polishing
surface of the polishing pad for use in the chemical/mechanical
polishing work is plane-shaped. A to-be-polished surface of the
wafer and the polishing surface of the polishing pad are arranged
in parallel to each other. To polish, the wafer surface and the
polishing surface thus arranged are in contact with each other,
while being both rotated. Various types of polishing apparatuses
are used.
[0006] For example, in a polishing pad 100 as shown in FIGS. 16 and
17, a number of through holes, which pass through the polishing
pad, are arrayed on a polishing pad surface 101 made of foamed
urethane or the like. In a polishing pad 110 as shown in FIGS. 18
and 19, lattice like polishing grooves 112 are formed on a
polishing pad surface 111. The grooves function to feed and exhaust
an abrasive liquid and to effectively eject polishing waste (refer
to, for example, Jpn. Pat. Appln. KOKOKU Publication No. 62-34509
and Jpn. Pat. Appln. KOKAI Publication No. 2003-300149). In those
figures, W designates a wafer. Concentric circle- and spiral-shaped
polishing grooves are also known. Further, a polishing pad having a
combination of polishing grooves and through holes is also known. A
polishing pad having polishing grooves formed therein has a high
ability to feed and exhausting the abrasive liquid. Therefore, such
a pad is advantageous in that polishing amount variations in 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 enters the wafer center
through the grooves.
[0007] However, this type of polishing pad suffers from the
following problems. When the foamed urethane is abraded and the
polishing grooves wear away, the polishing grooves lose their
function of feeding and exhausting the abrasive liquid and of
ejecting the polishing waste. A depth of the polishing groove is
generally about the half of a thickness of the polishing pad. If
the depth of the polishing groove reaches the back side of the
polishing pad, the polishing pad is separated from the surface
plate and unable to exhibit its function.
[0008] In the case of the polishing pad having the through holes,
on the other hand, the polishing pad can exhibit its function just
before the polishing pad wears away. In this respect, its service
life is long. However, this type of polishing pad is low in its
ability to feed and exhaust the abrasive liquid. Because of this,
the polishing amount variations in the central part and the
peripheral end part are large. Further, it is difficult to peel the
wafer from the polishing pad since the polishing pad cannot feed
air to the central part of the wafer. Additionally, the wafer
sticks to the polishing pad during the polishing operation. The
wafer is easily forced out of the wafer carrier.
BRIEF SUMMARY OF THE INVENTION
[0009] To achieve the above object, there are provided a polishing
pad and a polishing apparatus.
[0010] According to one embodiment of the present invention, a
polishing pad which polishes a to-be-polished object is provided,
which includes a plate-like pad body having one surface serving as
a polishing surface and the other surface serving as a support
surface; and a plurality of hole parts which extend from the
polishing surface to the support surface, said each hole part
containing a plurality of elongated holes that extend in different
directions on a plane of the polishing surface.
[0011] According to another embodiment of the present invention, a
polishing apparatus is provided, which includes a polishing pad
provided on a surface plate; a holder member arranged to face the
polishing pad, the holder member holding a to-be-polished object;
and a drive mechanism which polishes the to-be-polished object by
relatively and frictionally moving the polishing pad and the
to-be-polished object held by the holder member, wherein the
polishing pad comprises: a plate-like pad body having one surface
serving as a polishing surface and the other surface serving as a
support surface attached to the surface plate; and a plurality of
hole parts which extend from the polishing surface to the support
surface, said each hole part containing a plurality of elongated
holes that extend in different directions on a plane of the
polishing surface.
[0012] According to another embodiment of the present invention, a
method of polishing a to-be-polishing surface of a to-be-polished
object, which includes holding a plate-like polishing pad provided
on a surface plate, the polishing pad having one surface serving as
a polishing surface and the other surface serving as a support
surface attached to the surface plate, and the pad body including a
plurality of hole parts which extend from the polishing surface to
the support surface, said each hole part containing a plurality of
elongated holes that extend in different directions on a plane of
the polishing surface; holding a to-be-polished object by a holder
member such that the to-be-polished object is arranged to face the
polishing pad; and moving the polishing pad relative to the
to-be-polished object in a friction manner.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0013] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate 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.
[0014] FIG. 1 is a side view showing a polishing apparatus having a
polishing pad assembled thereinto, which is an embodiment of the
present invention;
[0015] FIG. 2 is a plan view showing the polishing pad assembled
into the polishing apparatus;
[0016] FIG. 3 is a plan view showing a first modification of the
polishing pad;
[0017] FIG. 4 is a plan view showing a second modification of the
polishing pad;
[0018] FIG. 5 is a plan view showing a third modification of the
polishing pad;
[0019] FIG. 6 is a plan view showing a fourth modification of the
polishing pad;
[0020] FIG. 7 is a plan view showing a fifth modification of the
polishing pad;
[0021] FIG. 8 is a plan view showing a sixth modification of the
polishing pad;
[0022] FIG. 9 is a plan view showing a seventh modification of the
polishing pad;
[0023] FIG. 10 is a plan view showing an eighth modification of the
polishing pad;
[0024] FIG. 11 is a plan view showing a ninth modification of the
polishing pad;
[0025] FIG. 12 is a plan view showing a tenth modification of the
polishing pad;
[0026] FIG. 13 is a plan view showing an eleventh modification of
the polishing pad;
[0027] FIG. 14 is a plan view showing a twelfth modification of the
polishing pad;
[0028] FIG. 15 is an explanatory view showing an operation range in
the polishing apparatus;
[0029] FIG. 16 is a plan view showing a polishing pad with through
holes formed therein and a semiconductor wafer;
[0030] FIG. 17 is a cross sectional view showing a main portion of
the polishing pad;
[0031] FIG. 18 is a plan view showing a polishing pad with
polishing grooves formed therein and a semiconductor wafer; and
[0032] FIG. 19 is a cross sectional view showing a main portion of
the polishing pad.
DETAILED DESCRIPTION OF THE INVENTION
[0033] FIG. 1 is a side view showing a polishing apparatus 10,
which is a first embodiment of the present invention. FIG. 2 is a
plan view showing a polishing pad 20 assembled into the polishing
apparatus 10.
[0034] The polishing apparatus 10 is comprised of a rotation drive
mechanism 11, a surface plate 12 mounted to the rotation drive
mechanism 11, a holder mechanism 13 arranged facing the surface
plate 12, a moving mechanism 14 for driving the holder mechanism 13
and moving it along the upper surface of the surface plate 12, and
a nozzle 15 for feeding an abrasive liquid onto the surface plate
12.
[0035] A polishing pad 20 is detachably attached to the upper
surface of the surface plate 12, and a semiconductor wafer W as a
to-be-polished object is attached to the holder mechanism 13.
[0036] The polishing pad 20 is provided with a pad body 21 made of
resin such as foamed polyurethane or urethane. The pad body 21 is
attached to the surface plate 12 in a state that one surface of the
pad body 21 is faced upward as a polishing surface 22, while the
other surface serves as a support surface 23.
[0037] Hole parts 30 extend from the support surface 23 to the
polishing surface 22, i.e., in the thickness direction of the pad
body 21. The hole parts 30 may be formed by, for example, a
punching work. The hole parts 30 each take a cross-shape consisting
of four elongated holes 31 radially arranged as from the polishing
surface 22 side, as shown in FIG. 2. More specifically, a plurality
of elongated holes 31, which extend in different directions on a
plane (surface) of the polishing surface 22, are combined to form
each hole part 30.
[0038] An outer configuration of each hole part 30 has a size
ranging from 5 mm to 300 mm, for example. A width of each elongated
hole 31 ranges from 1 mm to 8 mm, for example. A distance between
the adjacent hole parts 30 is not larger than two times of the
outer configuration of the hole part 30.
[0039] It is noted that in the polishing pad 20 thus constructed,
the combination of the plurality of elongated holes forms the hole
part 30. This feature lowers the sealingness between the
to-be-polished surface of the semiconductor wafer W and the surface
of the polishing pad 1, and hence, hardly creates negative
pressure. Consequently, after the polishing work finishes, it is
easy to remove the to-be-polished object from the surface of the
polishing pad 1.
[0040] The hole parts 30 are formed so as to pass through the pad
body 21 in the thickness direction. For this reason, a time period
taken until the pad body 21 wears and the hole parts 30 wear away
is long. As a result, the pad life is elongated, and a frequency of
replacing the polishing pad 20 with a new one is reduced. Further,
the amount of the abrasive liquid flowing through the hole parts 30
is increased, so that the polishing is stable, and the flatness
uniformity of the surface is enhanced.
[0041] Unlike the polishing pad having the polishing grooves formed
therein, the abrasive liquid never flows through the polishing
grooves out of the polishing pad. The hole parts 30 keep the
abrasive liquid therein to thereby reduce the amount of the
abrasive liquid used.
[0042] The hole parts 30 are through holes. Accordingly, the hole
parts may be formed by a punching work, and hence, the
manufacturing cost is lower than that of the polishing pad having
the polishing grooves.
[0043] As described above, the polishing apparatus 10 using the
polishing pad 20 according to the present embodiment increases the
service life of the polishing pad 20, enhances the uniformity of
the polishing amount over the surface of the semiconductor wafer,
and prevents the wafer from sticking to the polishing pad.
[0044] While the polishing pad 20 uses a single layer pad body of
foamed urethane, it may have a multi-layered structure in which a
layer formed with soft unwoven fabric and a foamed urethane layer
(closer to the surface plate 12) layered on the former. In the case
of the multi-layered structure, the hole parts 30 are formed only
in the foamed urethane layer.
[0045] FIG. 3 is a plan view showing a polishing pad 20A according
to a first modification of the polishing pad 20. In the
modification, hole parts 40 are provided in place of the hole parts
30. The hole parts 40 each include three elongated holes 41. This
modification also produces useful effects, which are comparable
with those of the polishing pad 20.
[0046] FIG. 4 is a plan view showing a polishing pad 20B according
to a second modification of the polishing pad 20. In the
modification, hole parts 50 are provided in place of the hole parts
30. The hole parts 50 each include five elongated holes 41. This
modification also produces useful effects, which are comparable
with those of the polishing pad 20.
[0047] FIG. 5 is a plan view showing a polishing pad 20C according
to a third modification of the polishing pad 20. In the
modification, hole parts 60 are provided in place of the hole parts
30. The hole parts 60 each include six elongated holes 61. The
modification also produces useful effects, which are comparable
with those of the polishing pad 20.
[0048] FIG. 6 is a plan view showing a polishing pad 20D according
to a fourth modification of the polishing pad 20. In the
modification, an array of hole parts 30 are different from that of
those of the polishing pad 20 within such a range that the pad body
21 is not separated. As shown, the adjacent hole parts 30 are
coupled with one another within a spatial range within which the
pad body 21 is not separated from the surface plate. The
modification also produces useful effects, which are comparable
with those of the polishing pad 20.
[0049] FIG. 7 is a plan view showing a polishing pad 20E according
to a fifth modification of the polishing pad 20. In the
modification, a communication hole 32 interconnects the adjacent
hole parts 30. With provision of the communication holes 32, the
abrasive liquid is movable among the hole parts 30 to thereby
spread to the whole polishing pad 20E. This modification also
produces useful effects, which are comparable with those of the
polishing pad 20.
[0050] FIG. 8 is a plan view showing a polishing pad 20F according
to a sixth modification of the polishing pad 20. In the
modification, an array of hole parts 30 is different from that of
the hole parts of the polishing pad 20. That is, elongated holes
31, which are located closest to each other, are not aligned with
each other. The modification also produces useful effects, which
are comparable with those of the polishing pad 20.
[0051] FIG. 9 is a plan view showing a polishing pad 20G according
to a seventh modification of the polishing pad 20. In the
modification, an array of hole parts 30 is different from that of
the hole parts of the polishing pad 20. The hole parts 30 are
concentrically arrayed on the pad body 21. The modification also
produces useful effects, which are comparable with those of the
polishing pad 20.
[0052] FIG. 10 is a plan view showing a polishing pad 20H according
to an eighth modification of the polishing pad 20. In the
modification, an array of hole parts 30 is different from that of
the hole parts of the polishing pad 20. That is, hole parts 30 are
randomly arrayed. The modification also produces useful effects,
which are comparable with those of the polishing pad 20.
[0053] FIG. 10 is a plan view showing a polishing pad 20I according
to a ninth modification of the polishing pad 20. In the embodiment,
hole parts 30 and small hole parts 33, which are smaller than the
former, but similar to the former, are formed in the polishing pad.
The smaller hole parts 33 each include four elongated holes 34. The
hole parts 30 and the smaller hole parts 33 are alternately
arrayed. This modification also produces useful effects, which are
comparable with those of the polishing pad 20.
[0054] FIG. 12 is a plan view showing a polishing pad 20J according
to a tenth modification of the polishing pad 20. In the embodiment,
hole parts 30 and hole parts 70, which are different in shape from
the hole parts 30, are formed in the polishing pad. The hole parts
70 each include four arcuate elongated holes 71. The hole parts 30
and the hole parts 70 are alternately arrayed. The modification
also produces useful effects, which are comparable with those of
the polishing pad 20.
[0055] FIG. 13 is a plan view showing a polishing pad 20K according
to an eleventh modification of the polishing pad 20. In the
modification, hole parts 80 are provided in place of the hole parts
30. The hole parts 80 each include two elongated holes 81, which
are radial but unequal. The modification also produces useful
effects, which are comparable with those of the polishing pad
20.
[0056] FIG. 14 is a plan view showing a polishing pad 20L according
to a twelfth modification of the polishing pad 20. In the
modification, hole parts 90 are provided in place of the hole parts
30. The hole parts 90 also include four arcuate elongated holes 91.
The modification also produces useful effects, which are comparable
with those of the polishing pad 20.
[0057] FIG. 15 is an explanatory view showing a polishing pad 20M
according to a twelfth modification of the polishing pad 20 and an
operation range in the polishing apparatus 10. In the modification,
hole parts 30 are provided as in the polishing pad 20. The
modification also produces useful effects as in the already
described pads even when the hole parts 30 contain a hole part 30
with a chipped part 35, which is located on the peripheral part of
the pad body 21.
[0058] In this case, the moving range of the wafer W is restricted
as indicated by a two-dot chain line Q. This is because, if the
wafer W moves out of the area enclosed by the two-dot chain line Q,
it rubs the chipped part 50 to possibly be scratched. This
modification also produces useful effects, which are comparable
with those of the polishing pad 20.
[0059] It should be understood that the present invention is not
limited to the embodiments described above, but the invention may
be modified, altered and changed within the true spirits and the
scope of the invention. It is evident that a plurality of
components described in the embodiments may be appropriately
combined. If required, some components may be removed from all the
components described in the embodiments. Further, the components
used in the different embodiments may also be combined.
[0060] 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.
* * * * *