U.S. patent application number 11/505464 was filed with the patent office on 2006-12-07 for polishing cloth, polishing apparatus and method of manufacturing semiconductor devices.
Invention is credited to Hideaki Hirabayashi, Masahiro Ishidoya, Yoshihiro Oshibe, Akiko Saito, Naoaki Sakurai.
Application Number | 20060276113 11/505464 |
Document ID | / |
Family ID | 26601980 |
Filed Date | 2006-12-07 |
United States Patent
Application |
20060276113 |
Kind Code |
A1 |
Hirabayashi; Hideaki ; et
al. |
December 7, 2006 |
Polishing cloth, polishing apparatus and method of manufacturing
semiconductor devices
Abstract
There is disclosed a polishing cloth having an abrasive layer
containing a polymer material which is a hydrolyzable with an
aqueous medium and being capable of exhibiting a stable polishing
performance for a relatively long period of time without
necessitating a dressing treatment.
Inventors: |
Hirabayashi; Hideaki;
(Yokohama-shi, JP) ; Saito; Akiko; (Yokohama-shi,
JP) ; Sakurai; Naoaki; (Yokohama-shi, JP) ;
Oshibe; Yoshihiro; (Chita-gun, JP) ; Ishidoya;
Masahiro; (Chigasaki-shi, JP) |
Correspondence
Address: |
C. IRVIN MCCLELLAND;OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Family ID: |
26601980 |
Appl. No.: |
11/505464 |
Filed: |
August 17, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10412298 |
Apr 14, 2003 |
7112125 |
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11505464 |
Aug 17, 2006 |
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PCT/JP01/08717 |
Oct 3, 2001 |
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10412298 |
Apr 14, 2003 |
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Current U.S.
Class: |
451/288 |
Current CPC
Class: |
B24B 49/16 20130101;
B24D 3/344 20130101; B24B 37/24 20130101; H01L 21/3212 20130101;
B24D 11/001 20130101; B24D 3/28 20130101; B24B 37/042 20130101 |
Class at
Publication: |
451/288 |
International
Class: |
B24B 29/00 20060101
B24B029/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 12, 2000 |
JP |
2000-312288 |
Jul 11, 2001 |
JP |
2001-210856 |
Claims
1-6. (canceled)
7. A polishing apparatus comprising: a turntable having a surface
which is covered with a polishing cloth having an abrasive layer
containing a polymer material which is a hydrolyzable with an
aqueous medium; holding means which is rotatively and vertically
movably disposed over the turntable and is designed to hold a
subject member to be polished, the holding means being also
designed to impose a desired magnitude of load on the subject
member to thereby enable the subject member to be press-contacted
with the abrasive cloth of the turntable, and further designed to
rotate in the same direction as that of the turntable; and feeding
means for feeding a polishing slurry containing abrasive grains to
the polishing cloth.
8. A polishing apparatus comprising: a turntable having a surface
which is covered with a polishing cloth having an abrasive layer
containing a polymer material which is a soluble in an aqueous
medium; holding means which is rotatively and vertically movably
disposed over the turntable and is designed to hold a subject
member to be polished, the holding means being also designed to
impose a desired magnitude of load on the subject member to thereby
enable the subject member to be press-contacted with the abrasive
cloth of the turntable, and further designed to rotate in the same
direction as that of the turntable; and feeding means for feeding a
polishing slurry containing abrasive grains to the polishing
cloth.
9. A polishing apparatus comprising: a turntable having a surface
which is covered with a polishing cloth having an abrasive layer
containing a polymer material which is a soluble in an aqueous
medium and abrasive grains, the abrasive grains being dispersed in
the polymer material; holding means which is rotatively and
vertically movably disposed over the turntable and is designed to
hold a subject member to be polished, the holding means being also
designed to impose a desired magnitude of load on the subject
member to thereby enable the subject member to be press-contacted
with the abrasive cloth of the turntable, and further designed to
rotate in the same direction as that of the turntable; and feeding
means for feeding a polishing composition containing at least water
and abrasive grain free to the polishing cloth.
10. A polishing apparatus comprising: a turntable having a surface
which is covered with a polishing cloth having an abrasive layer, a
surface portion of which is permitted to elute in the presence of
an aqueous medium, when the abrasive layer is subjected to
frictional stress; holding means which is rotatively and vertically
movably disposed over the turntable and is designed to hold a
subject member to be polished, the holding means being also
designed to impose a desired magnitude of load on the subject
member to thereby enable the subject member to be press-contacted
with the abrasive cloth of the turntable, and further designed to
rotate in the same direction as that of the turntable; and feeding
means for feeding a polishing slurry containing abrasive grains to
the polishing cloth.
11. A polishing apparatus comprising: a turntable having a surface
which is covered with a polishing cloth having an abrasive layer
having dispersed therein abrasive grains, wherein a surface portion
of the abrasive layer is permitted to elute in the presence of an
aqueous medium, when the abrasive layer is subjected to frictional
stress, concomitantly permitting the abrasive grains to be supplied
to the surface of the abrasive layer; holding means which is
rotatively and vertically movably disposed over the turntable and
is designed to hold a subject member to be polished, the holding
means being also designed to impose a desired magnitude of load on
the subject member to thereby enable the subject member to be
press-contacted with the abrasive cloth of the turntable, and
further designed to rotate in the same direction as that of the
turntable; and feeding means for feeding a polishing composition
containing at least water and abrasive grain free to the polishing
cloth.
12. The polishing apparatus according to claim 7, wherein the
structure in the polymer material, which is a hydrolyzable with an
aqueous medium is represented by the following formula (I) or (II):
##STR86## wherein R.sup.1, R.sup.2 and R.sup.3 may be the same or
different and are individually hydrogen atom, an alkyl group or
aryl group: ##STR87## wherein R.sup.4, R.sup.5 and R.sup.6 may be
the same or different and are individually hydrogen atom or an
organic group having 1 to 18 carbon atoms; R.sup.7 is an organic
group having 1 to 18 carbon atoms; and R.sup.6 and R.sup.7 may be
connected together to form a heterocycle having Y.sup.1, as a
heteroatom, Y.sup.1 being oxygen atom or sulfur atom.
13. The polishing apparatus according to claim 7, wherein the
polymer material is .A-inverted.,.E-backward.-unsaturated
homopolymer or copolymer each having a repeating unit of monomer
represented by the following formula (III), (IV), (V) or (VI):
##STR88## wherein R.sup.1, R.sup.2 and R.sup.3 may be the same or
different and are individually hydrogen atom, an alkyl group or
aryl group: ##STR89## wherein R.sup.1, R.sup.2 and R.sup.3 may be
the same or different and are individually hydrogen atom, an alkyl
group or aryl group: ##STR90## wherein R.sup.4, R.sup.5 and R.sup.6
may be the same or different and are individually hydrogen atom or
an organic group having 1 to 18 carbon atoms; R.sup.7 is an organic
group having 1 to 18 carbon atoms; and R.sup.6 and R.sup.7 may be
connected together to form a heterocycle having Y.sup.1 as a
heteroatom, Y.sup.1 being oxygen atom or sulfur atom. ##STR91##
wherein R.sup.4, R.sup.5 and R.sup.6 may be the same or different
and are individually hydrogen atom or an organic group having 1 to
18 carbon atoms; R.sup.7 is an organic group having 1 to 18 carbon
atoms; and R.sup.6 and R.sup.7 may be connected together to form a
heterocycle having Y.sup.1 as a heteroatom, Y.sup.1 being oxygen
atom or sulfur atom.
14. The polishing apparatus according to claim 7, wherein abrasive
grain in the polishing slurry is at least one oxide selected from
the group consisting of cerium oxide, manganese oxide, silica,
alumina and zirconia.
15. The polishing cloth according to claim 8, wherein the polymer
material is a soluble in an aqueous medium at a rate of 0.01 to
10.0 mg/min. when a relative velocity between the abrasive layer
and the subject member to be polished is set to 1.0 m/sec. under a
condition where the subject member contacts the abrasive layer by
applying a load of 300 gf/cm.sup.2 to the subject member.
16. The polishing cloth according to claim 8, wherein the polymer
material is a homopolymer or a copolymer to be derived from a
polymerization of at least one monomer selected from the group
consisting of acrylic acid, methacrylic acid, itaconic acid,
fumaric acid, maleic acid, hydroxyalkyl acrylate, hydroxyalkyl
methacrylate, N-vinyl-2-pyrrolidone, methylvinyl ether,
N-vinylformamide and N,Ndimethylacryl amide.
17. The polishing apparatus according to claim 8, wherein abrasive
grain in the polishing slurry is at least one oxide selected from
the group consisting of cerium oxide, manganese oxide, silica,
alumina and zirconia.
18. The polishing cloth according to claim 9, wherein the polymer
material is a soluble in an aqueous medium at a rate of 0.01 to
10.0 mg/min. when a relative velocity between the abrasive layer
and the subject member to be polished is set to 1.0 m/sec. under a
condition where the subject member contacts the abrasive layer by
applying a load of 300 gf/cm.sup.2 to the subject member.
19. The polishing cloth according to claim 9, wherein the polymer
material is a homopolymer or a copolymer to be derived from a
polymerization of at least one monomer selected from the group
consisting of acrylic acid, methacrylic acid, itaconic acid,
fumaric acid, maleic acid, hydroxyalkyl acrylate, hydroxyalkyl
methacrylate, N-vinyl-2-pyrrolidone, methylvinyl ether,
N-vinylformamide and N,N-dimethylacryl amide.
20. The polishing apparatus according to claim 9, wherein abrasive
grain in the abrasive layer is at least one oxide selected from the
group consisting of cerium oxide, manganese oxide, silica, alumina
and zirconia.
21. The polishing cloth according to claim 10, wherein the
frictional stress is the force applied to the abrasive layer when a
relative velocity between the abrasive layer and a subject member
to be polished is set to 0.2 to 3.0 m/sec. under a condition where
the subject member is permitted to contact the abrasive layer by
applying a load of 150 to 500 gf/cm.sup.2 to the subject
member.
22. The polishing apparatus according to claim 10, wherein abrasive
grain in the polishing slurry is at least one oxide selected from
the group consisting of cerium oxide, manganese oxide, silica,
alumina and zirconia.
23. The polishing cloth according to claim 11, wherein the
frictional stress is the force applied to the abrasive layer when a
relative velocity between the abrasive layer and a subject member
to be polished is set to 0.2 to 3.0 m/sec. under a condition where
the subject member is permitted to contact the abrasive layer by
applying a load of 150 to 500 gf/cm.sup.2 to the subject
member.
24. The polishing apparatus according to claim 11, wherein abrasive
grain in the abrasive layer is at least one oxide selected from the
group consisting of cerium oxide, manganese oxide, silica, alumina
and zirconia.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S.
application Ser. No. 10/412,298, filed Apr. 14, 2003, now allowed,
which is a continuation application of PCT Application No.
PCT/JP01/08717, filed Oct. 3, 2001, which was not published under
PCT Article 21(2) in English, and which is based on and claims the
benefit of priority from the prior Japanese Patent Applications No.
2000-312288, filed Oct. 12, 2000; and No. 2001-210856, filed Jul.
11, 2001, the entire contents of all of which are incorporated
herein by 0reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a polishing cloth, a
polishing apparatus and a method of manufacturing semiconductor
devices.
[0004] 2. Description of the Related Art
[0005] A polishing apparatus provided with a polishing cloth has
been conventionally employed in the manufacture of a semiconductor
device when it is desired to mirror-finish a semiconductor
substrate (for example, a semiconductor wafer), to flatten an
insulating film deposited on a semiconductor wafer, or to perform
the back etching of a metal film to form a buried wiring.
[0006] This polishing apparatus is generally formed of a structure
comprising a turntable whose surface is constituted by an
underlying layer formed of rigid polyurethane foam or of a 2-ply
structure consisting of a rigid polyurethane foam layer and a
polyurethane nonwoven fabric layer, and by a polishing cloth having
a rough surface and covering the underlying layer; a supply pipe
for feeding a polishing slurry containing abrasive grains to the
polishing cloth; and a holder rotatively and vertically movably
disposed over the turntable. When it is desired to flatten an
insulating film deposited on wirings formed on the surface of
semiconductor wafer for example, this polishing apparatus can be
operated as follows. First of all, the semiconductor wafer is held
by making use of the holder in such a manner that the insulating
film to be polished faces the polishing cloth, and, while keeping
the feeding of a polishing slurry containing abrasive grains to the
polishing cloth, the semiconductor wafer is permitted to contact
with the polishing cloth by applying a desired magnitude of load to
the semiconductor wafer by means of the holder. On this occasion,
the holder and the turntable are kept rotating in the same
direction with each other.
[0007] In this polishing operation, the open interstices (generally
40-50 .mu.m in diameter) of the polishing cloth are filled with
abrasive grains having a diameter of 0.2 .mu.m and included in the
polishing slurry, thereby enabling the abrasive grains to be
homogenously dispersed at the interface between the polishing cloth
and the semiconductor wafer. At the same time, the abrasive grains
are also permitted to remain at the portions of the polishing cloth
which are located between the open interstices. As a result, the
insulating film can be mechanically polished, thus achieving the
flattening of the surface of the insulating film.
[0008] However, when this polishing operation is continued for a
long period of time, the abrasive grains are accumulated in the
open interstices, thus increasing the quantity of the abrasive
grains on the portions located between the open interstices of the
polishing cloth. Namely, the polishing power by the abrasive grains
is enhanced. As a result, the polishing rate is increased as
compared with the initial polishing rate, thus bringing out
so-called fluctuation of polishing performance.
[0009] The polishing cloth which fluctuates in polishing
performance as described above has been conventionally subjected to
a regeneration treatment by making use of a dressing apparatus
provided with a dressing tool having a large number of diamond
particles electrodeposited on a metallic substrate. However, it is
very difficult to avoid this fluctuation of polishing performance
of polishing cloth unless the aforementioned dressing treatment is
performed after finishing every polishing operation. This makes the
polishing operation very troublesome because of the inclusion of
the aforementioned dressing treatment.
BRIEF SUMMARY OF THE INVENTION
[0010] An object of the present invention is to provide a polishing
cloth which is capable of exhibiting a stable polishing performance
for a relatively long period of time without necessitating a
dressing treatment.
[0011] Another object of the present invention is to provide a
polishing cloth which is provided with an automatic abrasive
grain-feeding capability and capable of exhibiting a stable
polishing performance for a relatively long period of time without
necessitating a dressing treatment.
[0012] A further object of the present invention is to provide a
polishing apparatus provided with aforementioned cloth capable of
exhibiting a stable polishing performance.
[0013] A further object of the present invention is to provide a
method of manufacturing a semiconductor device, which makes it
possible to reliably form a conductive member, such as a buried
wiring layer, with high precision in at least one embedding portion
selected from groove and opening formed in an insulating film which
has been deposited on a semiconductor substrate.
[0014] According to the present invention, there is provided a
polishing cloth comprising an abrasive layer containing a polymer
material which is a hydrolyzable with an aqueous medium.
[0015] According to the present invention, there is also provided a
polishing cloth comprising an abrasive layer containing a polymer
material which is a hydrolyzable with an aqueous medium and at
least one abrasive grain selected from the group consisting of
cerium oxide, manganese oxide, silica, alumina and zirconia, the
abrasive grain being dispersed in the polymer material.
[0016] According to the present invention, there is also provided a
polishing cloth comprising an abrasive layer containing a polymer
material which is a soluble in an aqueous medium.
[0017] According to the present invention, there is also provided a
polishing cloth comprising an abrasive layer containing a polymer
material which is a soluble in an aqueous medium and at least one
kind of abrasive grain selected from the group consisting of cerium
oxide, manganese oxide, silica, alumina and zirconia, the abrasive
grain being dispersed in the polymer material.
[0018] According to the present invention, there is also provided a
polishing cloth comprising an abrasive layer having dispersed
therein at least one abrasive grain selected from the group
consisting of cerium oxide, manganese oxide, silica, alumina and
zirconia, wherein a surface portion of the abrasive layer is
prohibited from eluting in the presence of an aqueous medium, until
the abrasive layer is subjected to frictional stress, and is
permitted to elute in the presence of an aqueous medium, when the
abrasive layer is subjected to frictional stress, concomitantly
permitting the abrasive grain to be supplied to the surface of the
abrasive layer.
[0019] According to the present invention, there is also provided a
polishing apparatus comprising:
[0020] a turntable having a surface which is covered with a
polishing cloth having an abrasive layer containing a polymer
material which is a hydrolyzable with an aqueous medium;
[0021] holding means which is rotatively and vertically movably
disposed over the turntable and is designed to hold a subject
member to be polished, the holding means being also designed to
impose a desired magnitude of load on the subject member to thereby
enable the subject member to be press-contacted with the abrasive
cloth of the turntable, and further designed to rotate in the same
direction as that of the turntable; and
[0022] feeding means for feeding a polishing slurry containing
abrasive grains to the polishing cloth.
[0023] According to the present invention, there is also provided a
polishing apparatus comprising:
[0024] a turntable having a surface which is covered with a
polishing cloth having an abrasive layer containing a polymer
material which is a hydrolyzable with an aqueous medium and at
least one abrasive grain selected from the group consisting of
cerium oxide, manganese oxide, silica, alumina and zirconia, the
abrasive grain being dispersed in the polymer material;
[0025] holding means which is rotatively and vertically movably
disposed over the turntable and is designed to hold a subject
member to be polished, the holding means being also designed to
impose a desired magnitude of load on the subject member to thereby
enable the subject member to be press-contacted with the abrasive
cloth of the turntable, and further designed to rotate in the same
direction as that of the turntable; and
[0026] feeding means for feeding a polishing composition containing
at least water and abrasive grain free to the polishing cloth.
[0027] According to the present invention, there is also provided a
polishing apparatus comprising:
[0028] a turntable having a surface which is covered with a
polishing cloth having an abrasive layer containing a polymer
material which is a soluble in an aqueous medium;
[0029] holding means which is rotatively and vertically movably
disposed over the turntable and is designed to hold a subject
member to be polished, the holding means being also designed to
impose a desired magnitude of load on the subject member to thereby
enable the subject member to be press-contacted with the abrasive
cloth of the turntable, and further designed to rotate in the same
direction as that of the turntable; and
[0030] feeding means for feeding a polishing slurry containing
abrasive grains to the polishing cloth.
[0031] According to the present invention, there is also provided a
polishing apparatus comprising:
[0032] a turntable having a surface which is covered with a
polishing cloth having an abrasive layer containing a polymer
material which is a soluble in an aqueous medium and at least one
abrasive grain selected from the group consisting of cerium oxide,
manganese oxide, silica, alumina and zirconia, the abrasive grain
being dispersed in the polymer material;
[0033] holding means which is rotatively and vertically movably
disposed over the turntable and is designed to hold a subject
member to be polished, the holding means being also designed to
impose a desired magnitude of load on the subject member to thereby
enable the subject member to be press-contacted with the abrasive
cloth of the turntable, and further designed to rotate in the same
direction as that of the turntable; and
[0034] feeding means for feeding a polishing composition containing
at least water and abrasive grain free to the polishing cloth.
[0035] According to the present invention, there is also provided a
polishing apparatus comprising:
[0036] a turntable having a surface which is covered with a
polishing cloth including an abrasive layer, a surface portion of
which is permitted to elute in the presence of an aqueous medium,
when the abrasive layer is subjected to frictional stress;
[0037] holding means which is rotatively and vertically movably
disposed over the turntable and is designed to hold a subject
member to be polished, the holding means being also designed to
impose a desired magnitude of load on the subject member to thereby
enable the subject member to be press-contacted with the abrasive
cloth of the turntable, and further designed to rotate in the same
direction as that of the turntable; and
[0038] feeding means for feeding a polishing slurry containing
abrasive grains to the polishing cloth.
[0039] According to the present invention, there is also provided a
polishing apparatus comprising:
[0040] a turntable having a surface which is covered with a
polishing cloth including an abrasive layer having dispersed
therein at least one abrasive grain selected from the group
consisting of cerium oxide, manganese oxide, silica, alumina and
zirconia, wherein a surface portion of the abrasive layer is
permitted to elute in the presence of an aqueous medium, when the
abrasive layer is subjected to frictional stress, concomitantly
permitting the abrasive grain to be supplied to the surface of the
abrasive layer;
[0041] holding means which is rotatively and vertically movably
disposed over the turntable and is designed to hold a subject
member to be polished, the holding means being also designed to
impose a desired magnitude of load on the subject member to thereby
enable the subject member to be press-contacted with the abrasive
cloth of the turntable, and further designed to rotate in the same
direction as that of the turntable; and
[0042] feeding means for feeding a polishing composition containing
at least water and abrasive grain free to the polishing cloth.
[0043] According to the present invention, there is also provided a
method of manufacturing a semiconductor device, which comprises the
steps of:
[0044] providing a polishing apparatus comprising, [0045] (a) a
turntable having a surface which is covered with a polishing cloth
having an abrasive layer containing a polymer material which is a
hydrolyzable with an aqueous medium; [0046] (b) holding means which
is rotatively and vertically movably disposed over the turntable
and is designed to hold a subject member to be polished, the
holding means being also designed to impose a desired magnitude of
load on the subject member to thereby enable the subject member to
be press-contacted with the abrasive cloth of the turntable, and
further designed to rotate in the same direction as that of the
turntable; and [0047] (c) feeding means for feeding a polishing
slurry containing abrasive grains to the polishing cloth,
[0048] forming at least one embedding portion selected from a
groove corresponding to a configuration of a wiring layer and an
opening corresponding to a configuration of a via-fill in an
insulating film deposited on a semiconductor substrate;
[0049] forming a wiring material film made of copper or copper
alloy on a surface of the insulating film including the inner
surface of the embedding portion; and
[0050] polishing the wiring material film by making use of the
polishing apparatus, thereby forming at least one conductive member
selected from a wiring layer and a via-fill in the embedding
portion.
[0051] According to the present invention, there is also provided a
method of manufacturing a semiconductor device, which comprises the
steps of:
[0052] providing a polishing apparatus comprising, [0053] (a) a
turntable having a surface which is covered with a polishing cloth
having an abrasive layer containing a polymer material which is a
hydrolyzable with an aqueous medium and at least one abrasive grain
selected from the group consisting of cerium oxide, manganese
oxide, silica, alumina and zirconia, the abrasive grain being
dispersed in the polymer material; [0054] (b) holding means which
is rotatively and vertically movably disposed over the turntable
and is designed to hold a subject member to be polished, the
holding means being also designed to impose a desired magnitude of
load on the subject member to thereby enable the subject member to
be press-contacted with the abrasive cloth of the turntable, and
further designed to rotate in the same direction as that of the
turntable; and [0055] (c) feeding means for feeding a polishing
composition containing at least water and abrasive grain free to
the polishing cloth,
[0056] forming at least one embedding portion selected from a
groove corresponding to a configuration of a wiring layer and an
opening corresponding to a configuration of a via-fill in an
insulating film deposited on a semiconductor substrate;
[0057] forming a wiring material film made of copper or copper
alloy on a surface of the insulating film including the inner
surface of the embedding portion; and
[0058] polishing the wiring material film by making use of the
polishing apparatus, thereby forming at least one conductive member
selected from a wiring layer and a via-fill in the embedding
portion.
[0059] According to the present invention, there is also provided a
method of manufacturing a semiconductor device, which comprises the
steps of:
[0060] providing a polishing apparatus comprising, [0061] (a) a
turntable having a surface which is covered with a polishing cloth
having an abrasive layer containing a polymer material which is a
soluble in an aqueous medium; [0062] (b) holding means which is
rotatively and vertically movably disposed over the turntable and
is designed to hold a subject member to be polished, the holding
means being also designed to impose a desired magnitude of load on
the subject member to thereby enable the subject member to be
press-contacted with the abrasive cloth of the turntable, and
further designed to rotate in the same direction as that of the
turntable; and [0063] (c) feeding means for feeding a polishing
slurry containing abrasive grains to the polishing cloth,
[0064] forming at least one embedding portion selected from a
groove corresponding to a configuration of a wiring layer and an
opening corresponding to a configuration of a via-fill in an
insulating film deposited on a semiconductor substrate;
[0065] forming a wiring material film made of copper or copper
alloy on a surface of the insulating film including the inner
surface of the embedding portion; and
[0066] polishing the wiring material film by making use of the
polishing apparatus, thereby forming at least one conductive member
selected from a wiring layer and a via-fill in the embedding
portion.
[0067] According to the present invention, there is also provided a
method of manufacturing a semiconductor device, which comprises the
steps of:
[0068] providing a polishing apparatus comprising, [0069] (a) a
turntable having a surface which is covered with a polishing cloth
having an abrasive layer containing a polymer material which is a
soluble in an aqueous medium and at least one abrasive grain
selected from the group consisting of cerium oxide, manganese
oxide, silica, alumina and zirconia, the abrasive grain being
dispersed in the polymer material; [0070] (b) holding means which
is rotatively and vertically movably disposed over the turntable
and is designed to hold a subject member to be polished, the
holding means being also designed to impose a desired magnitude of
load on the subject member to thereby enable the subject member to
be press-contacted with the abrasive cloth of the turntable, and
further designed to rotate in the same direction as that of the
turntable; and [0071] (c) feeding means for feeding a polishing
composition containing at least water and abrasive grain free to
the polishing cloth,
[0072] forming at least one embedding portion selected from a
groove corresponding to a configuration of a wiring layer and an
opening corresponding to a configuration of a via-fill in an
insulating film deposited on a semiconductor substrate;
[0073] forming a wiring material film made of copper or copper
alloy on a surface of the insulating film including the inner
surface of the embedding portion; and
[0074] polishing the wiring material film by making use of the
polishing apparatus, thereby forming at least one conductive member
selected from a wiring layer and a via-fill in the embedding
portion.
[0075] According to the present invention, there is also provided a
method of manufacturing a semiconductor device, which comprises the
steps of:
[0076] providing a polishing apparatus comprising, [0077] (a) a
turntable having a surface which is covered with a polishing cloth
having an abrasive layer, a surface portion of which is permitted
to elute in the presence of an aqueous medium, when the abrasive
layer is subjected to frictional stress; [0078] (b) holding means
which is rotatively and vertically movably disposed over the
turntable and is designed to hold a subject member to be polished,
the holding means being also designed to impose a desired magnitude
of load on the subject member to thereby enable the subject member
to be press-contacted with the abrasive cloth of the turntable, and
further designed to rotate in the same direction as that of the
turntable; and [0079] (c) feeding means for feeding a polishing
slurry containing abrasive grains to the polishing cloth,
[0080] forming at least one embedding portion selected from a
groove corresponding to a configuration of a wiring layer and an
opening corresponding to a configuration of a via-fill in an
insulating film deposited on a semiconductor substrate;
[0081] forming a wiring material film made of copper or copper
alloy on a surface of the insulating film including the inner
surface of the embedding portion; and
[0082] polishing the wiring material film by making use of the
polishing apparatus, thereby forming at least one conductive member
selected from a wiring layer and a via-fill in the embedding
portion.
[0083] According to the present invention, there is also provided a
method of manufacturing a semiconductor device, which comprises the
steps of:
[0084] providing a polishing apparatus comprising, [0085] (a) a
turntable having a surface which is covered with a polishing cloth
including an abrasive layer having dispersed therein at least one
abrasive grain selected from the group consisting of cerium oxide,
manganese oxide, silica, alumina and zirconia, wherein a surface
portion of the abrasive layer is permitted to elute in the presence
of an aqueous medium, when the abrasive layer is subjected to
frictional stress, concomitantly permitting the abrasive grain to
be supplied to the surface of the abrasive layer; [0086] (b)
holding means which is rotatively and vertically movably disposed
over the turntable and is designed to hold a subject member to be
polished, the holding means being also designed to impose a desired
magnitude of load on the subject member to thereby enable the
subject member to be press-contacted with the abrasive cloth of the
turntable, and further designed to rotate in the same direction as
that of the turntable; and [0087] (c) feeding means for feeding a
polishing composition containing at least water and abrasive grain
free to the polishing cloth,
[0088] forming at least one embedding portion selected from a
groove corresponding to a configuration of a wiring layer and an
opening corresponding to a configuration of a via-fill in an
insulating film deposited on a semiconductor substrate;
[0089] forming a wiring material film made of copper or copper
alloy on a surface of the insulating film including the inner
surface of the embedding portion; and
[0090] polishing the wiring material film by making use of the
polishing apparatus, thereby forming at least one conductive member
selected from a wiring layer and a via-fill in the embedding
portion.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0091] FIG. 1 is a schematic view illustrating one embodiment of a
polishing apparatus according to the present invention;
[0092] FIG. 2 is a graph illustrating the relationship between the
polishing time and the polishing rate on the occasions when a
silicon oxide film is polished by making use of the polishing
apparatuses of Example 1 and Comparative Example 1; and
[0093] FIGS. 3A, 3B and 3C respectively show a cross-sectional view
illustrating the manufacturing step of a semiconductor device in
Example 8 of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0094] Next, the present invention will be explained in detail.
[0095] First of all, six kinds of polishing cloth according to the
present invention will be explained in detail.
[0096] (1) Polishing Cloth:
[0097] This polishing cloth comprises an abrasive layer containing
a polymer material which is a hydrolyzable with an aqueous medium.
Specific examples of this polishing cloth include those consisting
only of an abrasive layer which can be molded by way of injection
molding of the aforementioned polymer material, or those comprising
a substrate made of a material selected from various kinds of
materials such as metal, and an abrasive layer which is deposited
on the substrate for example by the casting of the aforementioned
polymer material.
[0098] This polymer material should preferably be selected from
those which comprise a backbone chain provided with a branched
chain having a structure that is a hydrolyzable with an aqueous
medium.
[0099] As for the structure which is a hydrolyzable with an aqueous
medium, those represented by the following formula (I) or (II) may
be exemplified: ##STR1##
[0100] wherein R.sup.1, R.sup.2 and R.sup.3 may be the same or
different and are individually hydrogen atom, an alkyl group or
aryl group: ##STR2##
[0101] wherein R.sup.4, R.sup.5 and R.sup.6 may be the same or
different and are individually hydrogen atom or an organic group
having 1 to 18 carbon atoms; R.sup.7 is an organic group having 1
to 18 carbon atoms; and R.sup.6 and R.sup.7 may be connected
together to form a heterocycle having Y.sup.1 as a heteroatom,
Y.sup.1 being oxygen atom or sulfur atom.
[0102] The R.sup.1, R.sup.2 and R.sup.3 in the aforementioned
formula (1) represent individually hydrogen atom, an alkyl group or
aryl group. Alkyl group in this case should preferably be selected
from those having 1 to 18 carbon atoms, more preferably from a
linear alkyl group, most preferably from a linear alkyl group
having 1 to 4 carbon atoms.
[0103] Specific examples of this alkyl group include methyl, ethyl,
n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, n-amyl, isoamyl,
sec-amyl, n-pentyl, n-octyl, dodecyl, cetyl, stearyl, etc.
[0104] As for aforementioned aryl group, it is possible to employ
phenyl, substituted phenyl, naphthyl, substituted naphthyl,
etc.
[0105] As for the examples of the polymer material where a branched
chain attached to the backbone chain thereof is formed of the
structure represented by the aforementioned formula (I) that is a
hydrolyzable with an aqueous medium, it is possible to employ a
homopolymer or a copolymer to be obtained through the
homopolymerization or copolymerization of, for example,
trialkylsilyl .alpha.,.beta.-unsaturated carboxylate which can be
produced through a reaction between carboxyl group-containing
.alpha.,.beta.-unsaturated monomer and trialkylsilyl chloride. As
for the specific examples of the carboxyl group-containing
.alpha.,.beta.-unsaturated monomer to be employed herein, it is
possible to employ acrylic acid, methacrylic acid, itaconic acid,
mesaconic acid, maleic acid, fumaric acid, etc. Further, as for
specific examples of the trialkylsilyl chloride, it is possible to
employ silyl chlorides of trimethyl, triethyl, tri-n-propyl,
tri-isopropyl, tri-n-butyl, tri-sec-butyl, tri-isobutyl,
tri-n-amyl, tri-isoamyl, tri-sec-amyl, tri-n-pentyl, tri-n-octyl,
tridecyl, tricetyl, triphenyl, tri-p-methylphenyl, tribenzyl,
etc.
[0106] As for the specific examples of the polymer material where a
branched chain attached to the backbone chain thereof is formed of
a structure represented by the aforementioned formula (I) that is a
hydrolyzable with an aqueous medium, it is possible to employ
.alpha.,.beta.-unsaturated homopolymer or copolymer each having a
repeating unit of monomer represented by the following formula
(III) or (IV): ##STR3##
[0107] wherein R.sup.1, R.sup.2 and R.sup.3 may be the same or
different and are individually hydrogen atom, an alkyl group or
aryl group.
[0108] As the specific examples of the trialkylsilyl
.alpha.,.beta.-unsaturated carboxylate (silyl acrylate) which
corresponds to the repeating unit of monomer represented by the
aforementioned formula (III), the compounds represented by the
following formulas (III-1) to (III-22) can be exemplified. As the
specific examples of the trialkylsilyl .alpha.,.beta.-unsaturated
carboxylate (silyl methacrylate) which corresponds to the repeating
unit of monomer represented by the aforementioned formula (IV), the
compounds represented by the following formulas (IV-1) to (IV-22)
can be exemplified.
Trimethylsilyl acrylate
[0109] ##STR4##
Triethylsilyl acrylate
[0110] ##STR5##
Tri-n-propylsilyl acrylate
[0111] ##STR6##
Tri-iso-propylsilyl acrylate
[0112] ##STR7##
Tri-n-butylsilyl acrylate
[0113] ##STR8##
Tri-iso-butylsilyl acrylate
[0114] ##STR9##
Tri-sec-butylsilyl acrylate
[0115] ##STR10##
Tri-n-amylsilyl acrylate
[0116] ##STR11##
Tri-n-hexylsilyl acrylate
[0117] ##STR12##
Tri-n-octylsilyl acrylate
[0118] ##STR13##
Tri-n-dodecylsilyl acrylate
[0119] ##STR14##
Triphenylsilyl acrylate
[0120] ##STR15##
Tri-p-methylphenyl acrylate
[0121] ##STR16##
Tribenzylsilyl acrylate
[0122] ##STR17##
Ethyldimethylsilyl acrylate
[0123] ##STR18##
n-butyldimethylsilyl acrylate
[0124] ##STR19##
Di-iso-propyl-n-butylsilyl acrylate
[0125] ##STR20##
n-octyl-di-n-butylsilyl acrylate
[0126] ##STR21##
Di-iso-propylstearylsilyl acrylate
[0127] ##STR22##
Dicyclohexylphenyl acrylate
[0128] ##STR23##
t-butylphenylsilyl acrylate
[0129] ##STR24##
Lauryldiphenylsilyl acrylate
[0130] ##STR25##
Trimethylsilyl methacrylate
[0131] ##STR26##
Triethylsilyl methacrylate
[0132] ##STR27##
Tri-n-propylsilyl methacrylate
[0133] ##STR28##
Tri-iso-propylsilyl methacrylate
[0134] ##STR29##
Tri-n-butylsilyl methacrylate
[0135] ##STR30##
Tri-iso-butylsilyl methacrylate
[0136] ##STR31##
Tri-sec-butylsilyl methacrylate
[0137] ##STR32##
Tri-n-amylsilyl methacrylate
[0138] ##STR33##
Tri-n-hexylsilyl methacrylate
[0139] ##STR34##
Tri-n-octylsilyl methacrylate
[0140] ##STR35##
Tri-n-dodecylsilyl methacrylate
[0141] ##STR36##
Triphenylsilyl methacrylate
[0142] ##STR37##
Tri-p-methylphenyl methacrylate
[0143] ##STR38##
Tribenzylsilyl methacrylate
[0144] ##STR39##
Ethyldimethylsilyl methacrylate
[0145] ##STR40##
n-butyldimethylsilyl methacrylate
[0146] ##STR41##
Di-iso-propyl-n-butylsilyl methacrylate
[0147] ##STR42##
n-octyl-di-n-butylsilyl methacrylate
[0148] ##STR43##
Di-iso-propylstearylsilyl methacrylate
[0149] ##STR44##
Dicyclohexylphenyl methacrylate
[0150] ##STR45##
t-butylphenylsilyl methacrylate
[0151] ##STR46##
Lauryldiphenylsilyl methacrylate
[0152] ##STR47##
[0153] Further, preferable examples of the trialkylsilyl
.alpha.,.beta.-unsaturated carboxylate are represented by the
following formulas (VII-1) to (VII-10).
Tri-iso-propylsilylmethyl maleate
[0154] ##STR48##
Tri-iso-propylsilylamyl maleate
[0155] ##STR49##
Tri-n-butylsilyl-n-butyl maleate
[0156] ##STR50##
t-butyldiphenylsilylmethyl maleate
[0157] ##STR51##
t-butyldiphenylsilyl-n-butyl maleate
[0158] ##STR52##
Tri-iso-propylsilylmethyl fumarate
[0159] ##STR53##
Tri-iso-propylsilylamyl fumarate
[0160] ##STR54##
Tri-n-butylsilyl-n-butyl fumarate
[0161] ##STR55##
t-butyldiphenylsilylmethyl fumarate
[0162] ##STR56##
t-butyldiphenylsilyl-n-butyl fumarate
[0163] ##STR57##
[0164] If the aforementioned polymer material is to be constituted
by a copolymer, it can be obtained through a copolymerization of
trialkylsilyl .alpha.,.beta.-unsaturated carboxylate with another
kind of monomer. As for the specific examples of the monomer to be
employed herein, it is possible to employ
.alpha.,.beta.-unsaturated monomers. As for the specific examples
of this .alpha.,.beta.-unsaturated monomers, it is possible to
employ methyl(metha)acrylate, ethyl(metha)acrylate,
n-propyl(metha)acrylate, isopropyl(metha)acrylate,
n-butyl(metha)acrylate, sec-butyl(metha)acrylate,
t-butyl(metha)acrylate, cyclohexyl(metha)acrylate,
2-ethylhexyl(metha)acrylate, lauryl(metha)acrylate,
stearyl(metha)acrylate, styrene, .alpha.-methylstyrene,
p-vinyltoluene, acrylonitrile, 2-hydroxyethyl(metha)acrylate, or
adducts of polyethylene glycol or polypropylene glycol with
2-hydroxyethyl(metha)acrylate, or methyl ether or ethyl ether
thereof.
[0165] The groups R.sup.4, R.sup.5 and R.sup.6 in the
aforementioned formula (II) may be the same or different and are
individually hydrogen atom or an organic group having 1 to 18
carbon atoms such as alkyl group, aryl group, alkanol, etc.;
R.sup.7 is alkyl group, aryl group or alkanol each having 1 to 18
carbon atoms and optionally having a substituent group; and R.sup.6
and R.sup.7 may be connected together to form a heterocycle having
Y.sup.1 as a heteroatom and optionally having a substituent group.
As for specific examples of this alkyl group, it is preferable to
employ methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl,
isobutyl, n-amyl, isoamyl, sec-amyl, n-pentyl, n-octyl, dodecyl,
cetyl, stearyl, etc.
[0166] The compound represented by the aforementioned formula (II)
and having a structure that is a hydrolyzable with an aqueous
medium can be easily obtained for example through a reaction
between a compound having carboxyl group (for example, a compound
having one or more, preferably 1 to 120 carboxylic groups per
molecule) and a compound selected from a vinyl ether compound
represented by the following formula (VIII), a vinyl thioether
compound, and a heterocyclic compound having a vinylic double bond
and a heteroatom which is constituted by oxygen atoms or sulfur
atoms. ##STR58##
[0167] wherein R.sup.4, R.sup.5 and R.sup.6 may be the same or
different and are individually hydrogen atom or an organic group
having 1 to 18 carbon atoms; R.sup.7 is an organic group having 1
to 18 carbon atoms; and R.sup.6 and R.sup.7 may be connected
together to form a heterocycle having Y.sup.1 as a heteroatom,
Y.sup.1 being oxygen atom or sulfur atom.
[0168] The groups R.sup.4, R.sup.5 and R.sup.6 in the
aforementioned formula (VIII) may be the same or different and are
individually hydrogen atom or an organic group having 1 to 18
carbon atoms such as alkyl group, aryl group, alkanol, etc.;
R.sup.7 is alkyl group, aryl group or alkanol each having 1 to 18
carbon atoms and optionally having a substituent group; and R.sup.6
and R.sup.7 may be connected together to form a heterocycle having
Y.sup.1 as a heteroatom and optionally having a substituent
group.
[0169] Specific examples of the compound that can be represented by
the aforementioned formula (VIII) are an aliphatic vinyl ether
compound such as methylvinyl ether, ethylvinyl ether,
isopropylvinyl ether, n-propylvinyl ether, n-butylvinyl ether,
isobutylvinyl ether, 2-ethylhexylvinyl ether, cyclohexylvinyl
ether, etc.; an aliphatic vinylthioether compound corresponding to
any one of the aforementioned ethers; a cyclic vinyl ether compound
such as 2,3-dihydrofuran, 3,4-dihydro-2H-pyrane, etc.; and a cyclic
vinylthioether compound corresponding to any one of the
aforementioned cyclic vinyl ethers.
[0170] Specific preferable examples of the polymer material having
at least one carboxylic group per molecule include for example
polyester resin, acrylic resin, maleic polybutadiene resin,
etc.
[0171] The reaction between the compound having at least one
carboxylic group per molecule and the compound represented by the
aforementioned formula (VIII) can be performed generally in the
presence of an acid catalyst and at a temperature ranging from room
temperature to 100.degree. C.
[0172] As for examples of the polymer material where a branched
chain attached to the backbone chain thereof is formed of the
structure represented by the aforementioned formula (II) that is a
hydrolyzable with an aqueous medium, it is possible to employ a
homopolymer or a copolymer to be obtained through the
homopolymerization or copolymerization of a reaction product to be
produced through a reaction between carboxyl group-containing
.alpha.,.beta.-unsaturated monomer and a compound represented by
the aforementioned formula (VIII). As for the specific examples of
the carboxyl group-containing .alpha.,.beta.-unsaturated monomer to
be employed herein, it is possible to employ acrylic acid,
methacrylic acid, itaconic acid, mesaconic acid, maleic acid,
fumaric acid, etc.
[0173] As for the specific examples of the polymer material where a
branched chain attached to the backbone chain thereof is formed of
a structure represented by the aforementioned formula (II) that is
a hydrolyzable with an aqueous medium, it is possible to employ
.alpha.,.beta.-unsaturated homopolymer or copolymer each having a
repeating unit of monomer represented by the following formula (V)
or (VI): ##STR59##
[0174] wherein R.sup.4, R.sup.5 and R.sup.6 may be the same or
different and are individually hydrogen atom or an organic group
having 1 to 18 carbon atoms; R.sup.7 is an organic group having 1
to 18 carbon atoms; and R.sup.6 and R.sup.7 may be connected
together to form a heterocycle having Y.sup.1 as a heteroatom,
Y.sup.1 being oxygen atom or sulfur atom.
[0175] The following formulas (V-1) to (V-8) are specific examples
of the reaction product (hemiacetal acrylate) which can be obtained
through a reaction between the carboxyl group-containing
.alpha.,.beta.-unsaturated monomer corresponding to the repeating
unit of monomer represented by the aforementioned formula (V) and a
compound represented by the aforementioned formula (VIII). Further,
the following formulas (VI-1) to (VI-8) are specific examples of
the reaction product (hemiacetal methacrylate) which can be
obtained through a reaction between the carboxyl group-containing
.alpha.,.beta.-unsaturated monomer of monomer corresponding to the
repeating unit represented by the aforementioned formula (VI) and a
compound represented by the aforementioned formula (VIII).
1-methoxyethyl acrylate
[0176] ##STR60##
1-ethoxyethyl acrylate
[0177] ##STR61##
1-n-propoxyethyl acrylate
[0178] ##STR62##
1-iso-propoxyethyl acrylate
[0179] ##STR63##
1-n-butoxyethyl acrylate
[0180] ##STR64##
1-iso-butoxyethyl acrylate
[0181] ##STR65##
1-(2-ethylhexoxy)ethyl acrylate
[0182] ##STR66##
Pyranyl acrylate
[0183] ##STR67##
1-methoxyethyl methacrylate
[0184] ##STR68##
1-ethoxyethyl methacrylate
[0185] ##STR69##
1-n-propoxyethyl methacrylate
[0186] ##STR70##
1-iso-propoxyethyl methacrylate
[0187] ##STR71##
1-n-butoxyethyl methacrylate
[0188] ##STR72##
1-iso-butoxyethyl methacrylate
[0189] ##STR73##
1-(2-ethylhexoxy)ethyl methacrylate
[0190] ##STR74##
Pyranyl methacrylate
[0191] ##STR75##
[0192] Other preferable examples of the reaction product which can
be obtained through a reaction between the carboxyl
group-containing .alpha.,.beta.-unsaturated monomer and a compound
represented by the aforementioned formula (VIII) are exemplified by
the following formulas (IX-1) to (IX-8).
Di-1-methoxyethyl maleate
[0193] ##STR76##
Di-1-ethoxyethyl maleate
[0194] ##STR77##
Di-1-n-propoxyethyl maleate
[0195] ##STR78##
Di-1-iso-propoxyethyl maleate
[0196] ##STR79##
Di-1-n-butoxyethyl maleate
[0197] ##STR80##
Di-1-iso-butoxyethyl maleate
[0198] ##STR81##
Di-1-(2-ethylhexoxy)ethyl maleate
[0199] ##STR82##
Dipyranyl maleate
[0200] ##STR83##
[0201] If the aforementioned polymer material is to be constituted
by a copolymer, it can be obtained through a copolymerization of a
reaction product to be derived from the reaction between carboxyl
group-containing .alpha.,.beta.-unsaturated monomer and the
compound represented by the aforementioned formula (VIII) with
another kind of monomer. As for specific examples of the monomer to
be employed herein, it is possible to employ
.alpha.,.beta.-unsaturated monomers. As for specific examples of
this .alpha.,.beta.-unsaturated monomers, it is possible to employ
methyl(metha)acrylate, ethyl(metha)acrylate,
n-propyl(metha)acrylate, isopropyl(metha)acrylate,
n-butyl(metha)acrylate, sec-butyl(metha)acrylate,
t-butyl(metha)acrylate, cyclohexyl(metha)acrylate,
2-ethylhexyl(metha)acrylate, lauryl(metha)acrylate,
stearyl(metha)acrylate, styrene, .alpha.-methylstyrene,
p-vinyltoluene, acrylonitrile, 2-hydroxyethyl(metha)acrylate, or
adducts of polyethylene glycol or polypropylene glycol with
2-hydroxyethyl(metha)acrylate, or methyl ether or ethyl ether
thereof.
[0202] The content of the repeating unit of monomer represented by
the aforementioned formula (III), (IV), (V) or (VI) in the
aforementioned polymer material should preferably be confined
within the range of 20 to 100% by weight, more preferably 40 to
100% by weight. If the content of the repeating unit of monomer is
less than 20% by weight, the quantity of carboxyl group to be
regenerated on the occasion of the hydrolysis of the polymer
material would become too small, thereby decreasing the solubility
of the polymer material in an aqueous medium, thus deteriorating
the polishing performance of the polishing cloth.
[0203] This polymer material should preferably be selected from
those having a number average molecular weight ranging from 500 to
500,000, more preferably from 500 to 100,000, and a glass
transition temperature ranging from 30 to 100.degree. C., more
preferably from 40 to 80.degree. C. A polishing cloth comprising a
polymer material having aforementioned specific ranges of number
average molecular weight and of glass transition temperature is
capable of further stabilizing the polishing performance thereof on
the occasion of polishing a subject member to be polished.
[0204] The aforementioned abrasive layer should preferably be
constructed such that particles of a substance which is higher in
solubility than that of the polymer material is dispersed in the
polymer material.
[0205] As for examples of such a substance, it is possible to
employ rosin, cellulose, polyvinyl alcohol, etc. The particles of
such a substance should preferably be dispersed at a ratio falling
within the range of 1 to 50% volume based on the polymer material.
Because, if the quantity of the dispersed particles is less than 1%
volume, it may become difficult to sufficiently enhance the effect
of these dispersed particles (the effects of promoting the
dissolution of the abrasive layer in the step of polishing). On the
other hand, if the quantity of the dispersed particles is higher
than 50% volume, the abrasive layer may be decomposed as soon as
the abrasive layer is immersed in an aqueous solution, thus making
the polishing cloth incapable of functioning.
[0206] (2) Polishing Cloth:
[0207] This polishing cloth comprises an abrasive layer containing
a polymer material which is a hydrolyzable with an aqueous medium
and at least one abrasive grain selected from the group consisting
of cerium oxide, manganese oxide, silica, alumina and zirconia, the
abrasive grain being dispersed in the polymer material. Specific
examples of this polishing cloth include those consisting only of
an abrasive layer which can be molded by way of injection molding
of the aforementioned polymer material, or those comprising a
substrate made of a material selected from various kinds of
material, such as metal, and an abrasive layer which is deposited
on the substrate, for example, by the casting of the aforementioned
polymer material.
[0208] The polymer material to be employed in this case may be the
same as employed in the aforementioned polishing cloth (1).
[0209] The abrasive grains should preferably be incorporated and
dispersed uniformly in the polymer material at a ratio ranging from
0.5 to 20% by weight.
[0210] The abrasive grains should preferably be spherical or nearly
spherical having an average particle diameter ranging from 0.02 to
0.11 .mu.m.
[0211] (3) Polishing Cloth:
[0212] This polishing cloth comprises an abrasive layer containing
a polymer material which is a soluble in an aqueous medium.
Specific examples of this polishing cloth include those consisting
only of an abrasive layer which can be molded by way of injection
molding of the aforementioned polymer material, or those comprising
a substrate made of a material selected from various kinds of
materials, such as metal, and an abrasive layer which is deposited
on the substrate, for example, by the casting of the aforementioned
polymer material.
[0213] This polymer material should preferably be selected from
those that are a soluble in an aqueous medium at a rate of 0.01 to
10.0 mg/min. when a relative velocity between the abrasive layer
and a subject member to be polished is set at 1.0 m/sec. under a
condition where the subject member is permitted to contact the
abrasive layer by applying a load of 300 gf/cm.sup.2 to the subject
member. When the dissolving rate of the polymer material is less
than 0.01 mg/min., it may become difficult to satisfactorily renew
the surface of the abrasive layer when the subject member to be
polished is being subjected to polishing by permitting the abrasive
layer and the subject member to rotate mutually while applying a
desired magnitude of load to the subject member and concurrently
feeding a polishing slurry containing abrasive grains and water to
the abrasive layer, thus possibly resulting in a local accumulation
of the abrasive grains on the surface of the abrasive layer. On the
other hand, when the dissolving rate of the polymer material is
higher than 10.0 mg/min., the polishing slurry may be forcedly
discharged from the abrasive layer due to an increased dissolution
rate of the surface of the abrasive layer during the polishing of
the subject member to be polished, thereby making it difficult to
sufficiently feed the abrasive grains of the slurry to an interface
between the abrasive layer and the subject member.
[0214] The polymer material may be a homopolymer or a copolymer
that can be derived from a polymerization of at least one monomer
selected from the group consisting of acrylic acid, methacrylic
acid, itaconic acid, fumaric acid, maleic acid, hydroxyalkyl
acrylate, hydroxyalkyl methacrylate, N-vinyl-2-pyrrolidone,
methylvinyl ether, N-vinylformamide and N,N-dimethylacryl
amide.
[0215] (4) Polishing Cloth:
[0216] This polishing cloth comprises an abrasive layer containing
a polymer material which is a soluble in an aqueous medium and at
least one abrasive grain selected from the group consisting of
cerium oxide, manganese oxide, silica, alumina and zirconia, the
abrasive grain being dispersed in the polymer material. Specific
examples of this polishing cloth include those consisting only of
an abrasive layer which can be molded by way of injection molding
of the aforementioned polymer material, or those comprising a
substrate made of a material selected from various kinds of
material, such as metal, and an abrasive layer which is deposited
on the substrate, for example, by the casting of the aforementioned
polymer material.
[0217] This polymer material to be employed in this case may be the
same as employed in the aforementioned polishing cloth (3).
[0218] The abrasive grains should preferably be incorporated and
dispersed uniformly in the polymer material at a ratio ranging from
0.5 to 20% by weight.
[0219] The abrasive grains should preferably be spherical or nearly
spherical having an average particle diameter ranging from 0.02 to
0.1 m.
[0220] (5) Polishing Cloth:
[0221] This polishing cloth comprises an abrasive layer, a surface
of which is prohibited from eluting in the presence of an aqueous
medium, until the abrasive layer is subjected to frictional stress,
and is permitted to elute in the presence of an aqueous medium,
when the abrasive layer is subjected to frictional stress.
[0222] In this case, the "frictional stress" means the force
applied to the abrasive layer when a relative velocity between the
abrasive layer and a subject member to be polished is set to 0.2 to
3.0 m/sec. under a condition where the subject member is permitted
to contact the abrasive layer by applying a load of 150 to 500
gf/cm.sup.2 to the subject member.
[0223] Specific examples of this polishing cloth include those
consisting only of an abrasive layer, or those comprising a
substrate made of a material selected from various kinds of
material, such as metal, and the aforementioned abrasive layer
which is deposited on the substrate.
[0224] The abrasive layer is formed of a material comprising a
polymer material (especially, a homopolymer or a copolymer each
having a repeating unit of monomer represented by the
aforementioned formula (III), (IV), (V) or (VI)) that can be
hydrolyzed by an aqueous medium as explained with reference to the
aforementioned polishing cloth (1).
[0225] (6) Polishing Cloth:
[0226] This polishing cloth comprises an abrasive layer having
dispersed therein at least one abrasive grain selected from the
group consisting of cerium oxide, manganese oxide, silica, alumina
and zirconia, wherein a surface portion of the abrasive layer is
prohibited from eluting in the presence of an aqueous medium, until
the abrasive layer is subjected to frictional stress, and is
permitted to elute in the presence of an aqueous medium, when the
abrasive layer is subjected to frictional stress, concomitantly
permitting the abrasive grains to be supplied to the surface of the
abrasive layer.
[0227] In this case, the "frictional stress" means the force
applied the abrasive layer when a relative velocity between the
abrasive layer and a subject member to be polished is set to 0.2 to
3.0 m/sec. under a condition where the subject member is permitted
to contact the abrasive layer by applying a load of 150 to 500
gf/cm.sup.2 to the subject member.
[0228] Specific examples of this polishing cloth include those
consisting only of an abrasive layer containing the aforementioned
abrasive grains, or those comprising a substrate made of a material
selected from various kinds of material, such as metal, and the
aforementioned abrasive layer containing the aforementioned
abrasive grains, which is deposited on the substrate.
[0229] The abrasive layer is formed of not only a material
comprising a polymer material (especially, a homopolymer or a
copolymer each having a repeating unit of monomer represented by
the aforementioned formula (III), (IV), (V) or (VI)) that can be
hydrolyzed by an aqueous medium as explained with reference to the
aforementioned polishing cloth (1) but also the aforementioned
abrasive grains.
[0230] The abrasive grains should preferably be incorporated and
dispersed uniformly in the abrasive layer at a ratio ranging from
0.5 to 20% by weight.
[0231] The abrasive grains should preferably be spherical or nearly
spherical having an average particle diameter ranging from 0.02 to
0.1 .mu.m.
[0232] Next, the polishing apparatus according to the present
invention will be explained with reference to FIG. 1.
[0233] A turntable 1 is covered thereon with a polishing cloth 2. A
supply pipe 3 for feeding a polishing slurry containing abrasive
grains and water and optionally containing a surfactant and a
dispersing agent if required, or a polishing composition not
containing abrasive grains but containing water and optionally
containing a surfactant and a dispersing agent if required, is
disposed over the polishing cloth 2. A substrate holder 5 having a
supporting shaft 4 on the top surface thereof is rotatively and
vertically movably disposed over the polishing cloth 2.
[0234] The examples of the surfactant to be contained in the
polishing slurry or in the polishing composition include for
example a nonionic surfactant such as polyethylene glycolphenyl
ether, ethylene glycol aliphatic acid ester, etc.; an amphoteric
surfactant such as imidazolybetaine; an anionic surfactant such as
sodium dodecyl sulfate; and a cationic surfactant such as stearin
trimethyl ammonium chloride.
[0235] As for the polishing cloth, it is possible to employ those
having the same structures as described in the aforementioned items
(1) to (6). However, when the polishing cloths of the
aforementioned items (1), (3) and (5) are to be employed in the
polishing treatment of the subject member, a polishing slurry
containing abrasive grains and water is fed from the feeding pipe 3
to the polishing cloth. On the other hand, when the polishing
cloths of the aforementioned items (2), (4) and (6) are to be
employed in the polishing treatment of the subject member, a
polishing composition containing water and abrasive grain free and,
if required, a surfactant and a dispersing agent is fed from the
feeding pipe 3 to the polishing cloth. Next, a specific polishing
method will be explained as follows.
[0236] (a) Polishing treatment by making use of a polishing
apparatus provided with a polishing cloth having any one of the
aforementioned structures (1), (3) and (5):
[0237] First of all, a subject member 6 to be polished, for
example, a substrate, is held by making use of the holder 5 in such
a way that the surface to be polished faces the polishing cloth 2.
Then, while keeping the feeding of a polishing slurry 7 containing
abrasive grains and water to the polishing cloth 2 from the feeding
pipe 3, a desired magnitude of load is imposed on the subject
member 6 so as to force the subject member 6 to contact the
polishing cloth 2 by means of the supporting shaft 4. Concurrently,
the holder 5 and the turntable 1 are caused to rotate in the same
direction with each other. As a result of this, the surface to be
polished of the subject member 6 is polished by the abrasive grains
in the polishing slurry which has been fed to an interface between
the subject member 6 and the polishing cloth 2.
[0238] (b) Polishing treatment by making use of a polishing
apparatus provided with a polishing cloth having any one of the
aforementioned structures (2), (4) and (6):
[0239] First of all, a subject member 6 to be polished, for
example, a substrate, is held by making use of the holder 5 in such
a way that the surface to be polished faces the polishing cloth 2.
Then, while keeping the feeding of a polishing composition
containing at least water and abrasive grain free to the polishing
cloth 2 from the feeding pipe 3, a desired magnitude of load is
imposed on the subject member 6 so as to force the subject member 6
to contact the polishing cloth 2 by means of the supporting shaft
4. Concurrently, the holder 5 and the turntable 1 are caused to
rotate in the same direction with each other. On this occasion, the
abrasive grains which are dispersed in the abrasive layer of the
polishing cloth are permitted to be fed, due to the elution of the
material of abrasive layer, to an interface between the face to be
polished of the subject member 6 and the abrasive layer. As a
result, the surface to be polished of the subject member 6 is
polished by the abrasive grains that have been fed from the
abrasive layer and in the presence of the polishing composition
containing water that has been fed from the feeding pipe 3.
[0240] Next, the method of manufacturing a semiconductor device
according to the present invention will be explained.
(A First Step)
[0241] At least one embedding portion selected from a groove and an
opening is formed in the surface of a substrate, and a wiring
material film made of copper or a copper alloy is deposited all
over the surface including the embedding portion of the
substrate.
[0242] As for the substrate, it is possible to employ for example a
semiconductor substrate or a glass substrate.
[0243] This embedding portion can be formed in an insulating film
formed on the substrate. As for specific examples of this
insulating film, it is possible to employ, for example, a silicon
oxide film, a boron-impregnated glass film (BPSG film), a
phosphorus-impregnated glass film (PSG film), etc. This insulating
film may be covered on the surface thereof with a polish-stopper
film formed of a material selected from silicon nitride, carbon,
alumina, boron nitride, diamond, etc.
[0244] As for the copper-based metal, it is possible to employ
copper (Cu) or a copper alloy such as a Cu--Si alloy, a Cu--Al
alloy, a Cu--Si--Al alloy, a Cu--Ag alloy, etc.
[0245] This wiring material film can be formed by means of sputter
deposition, vacuum deposition or plating, for instance.
[0246] A conductivity barrier layer may be deposited on the
insulating film including the embedding portion formed on the
surface of semiconductor substrate prior to the deposition of the
wiring material film on the insulating film. When such a
conductivity barrier layer is deposited on the insulating film
including the embedding portion, at least one buried conductive
member selected from a wiring layer and a via-fill can be formed in
the embedding portion surrounded by the conductivity barrier layer
as a result of the polishing treatment to be carried out, as
described later, subsequent to the deposition of the wiring
material film. As a result, Cu employed as a conductive member can
be prevented from being diffused into the insulating film by this
conductivity barrier film, thus preventing the semiconductor
substrate from being contaminated by Cu.
[0247] This conductivity barrier film may be formed of a single
layer or a multi-layer made of a material selected from the group
consisting for example of TiN, Ti, Nb, W, WN, TaN, TaSiN, Ta, Co,
Zr, ZrN and CuTa. Preferably, this conductivity barrier film may be
formed so as to have a thickness ranging from 15 to 50 nm.
(A Second Step)
[0248] The wiring material film formed on the substrate is
subjected to a polishing treatment by making use of a polishing
apparatus, thereby allowing the copper-based metal to be buried
inside the embedding portion, thus forming a buried conductive
member such as a buried wiring layer which is made of copper or a
copper alloy for instance.
[0249] Specifically, the buried conductive member can be formed by
way of the following methods.
[0250] (a) First of all, a semiconductor substrate 6 employed as a
subject member to be polished is held by making use of the holder 5
in such a way that the wiring material film made of copper or a
copper alloy is enabled to face the polishing cloth (a polishing
cloth having any one of the aforementioned structures (1), (3) and
(5)) 2. Then, while keeping the feeding of a polishing slurry 7
containing abrasive grains and water to the polishing cloth 2 from
the feeding pipe 3, a desired magnitude of load is imposed on the
semiconductor substrate 6 so as to force the semiconductor
substrate 6 to contact the polishing cloth 2 by means of the
supporting shaft 4. Concurrently, the holder 5 and the turntable 1
are caused to rotate in the same direction with each other. As a
result of this, the wiring material film of the semiconductor
substrate 6 is polished mainly by the abrasive grains in the
polishing slurry which has been fed to an interface between the
wiring material film and the polishing cloth 2, thereby forming a
buried conductive member wherein copper or a copper alloy is
embedded inside the embedding portion.
[0251] (b) First of all, a semiconductor substrate 6 employed as a
subject member to be polished is held by making use of the holder 5
in such a way that the wiring material film made of copper or a
copper alloy is enabled to face the polishing cloth (a polishing
cloth having any one of the aforementioned structures (2), (4) and
(6)) 2. Then, while keeping the feeding of a polishing composition
containing at least water and abrasive grain free to the polishing
cloth 2 from the feeding pipe 3, a desired magnitude of load is
imposed on the semiconductor substrate 6 so as to force the
semiconductor substrate 6 to contact the polishing cloth 2 by means
of the supporting shaft 4. Concurrently, the holder 5 and the
turntable 1 are caused to rotate in the same direction with each
other. On this occasion, the abrasive grains dispersed in the
abrasive layer of the polishing cloth may enter, due to the elution
of the material of abrasive layer, an interface between the wiring
material film of the substrate 6 and the abrasive layer. As a
result, the wiring material film of the substrate 6 is polished by
the abrasive grains that have been fed from the abrasive layer and
in the presence of the polishing composition containing water that
has been fed from the feeding pipe 3, thereby forming a buried
conductive member wherein copper or a copper alloy is embedded
inside the embedding portion.
[0252] The aforementioned polishing slurry or polishing composition
may further contain a water-soluble organic acid (first organic
acid) capable of reaction with copper to produce a copper complex
compound which is substantially insoluble in water and has a
mechanical strength lower than that of copper and an oxidizing
agent.
[0253] Specific examples of this first organic acid include for
example 2-quinoline carboxylic acid (quinaldinic acid), 2-pyridine
carboxylic acid, 2,6-pyridine carboxylic acid, quinolinic acid,
etc.
[0254] The mixing ratio of this first organic acid in the polishing
slurry or polishing composition should preferably be 0.1% by weight
or more. Further, if the mixing ratio of this first organic acid is
less than 0.1% by weight, it may become difficult to sufficiently
generate the copper complex which has a mechanical strength lower
than that of copper on the surface of the Cu or Cu alloy film. As a
result, it may become difficult to sufficiently promote the
polishing rate of the Cu or Cu alloy film at the polishing step
thereof. A more preferable mixing ratio of this first organic acid
would be in the range of 0.3 to 1.2% by weight.
[0255] The aforementioned oxidizing agent is effective in
generating copper hydrate when the polishing slurry or polishing
composition contacts the Cu or Cu alloy film. Specific examples of
this oxidizing agent are hydrogen peroxide (H.sub.2O.sub.2), sodium
hypochlorite (NaClO), etc.
[0256] The mixing ratio of this oxidizing agent in the polishing
slurry or polishing composition should preferably be at least ten
times (based on weight) as much as that of the first organic acid.
Because, if the mixing ratio of this oxidizing agent is less than
ten times (based on weight) relative to the first organic acid, it
may become difficult to sufficiently promote the generation of the
copper complex on the surface of the Cu or Cu alloy film. A more
preferable mixing ratio of this oxidizing agent relative to the
first organic acid would be not less than 30 times (based on
weight), more preferably not less than 50 times (based on weight)
relative to the first organic acid.
[0257] The aforementioned polishing slurry or polishing composition
may further contain an organic acid (a second organic acid) having
one carboxylic group and one hydroxyl group.
[0258] The aforementioned second organic acid is effective in
promoting the aforementioned effect of the oxidizing agent to
generate copper hydrate. Specific examples of this second organic
acid include lactic acid, tartaric acid, mandelic acid, malic acid,
etc. These acids may be employed singly or in combination of two or
more kinds. Among these acids, lactic acid is most preferable.
[0259] The mixing ratio of this second organic acid in the
polishing slurry or polishing composition should preferably be
confined within the range of 20 to 250% by weight based on the
weight of the first organic acid. Because, if the mixing ratio of
this second organic acid is less than 20% by weight, it may become
difficult to sufficiently promote the effect of the oxidizing agent
to generate copper hydrate. On the other hand, if the mixing ratio
of this second organic acid exceeds 250% by weight, the wiring
material film formed of copper or a copper alloy may be etched
away, thereby making it impossible to form a wiring pattern. A more
preferable mixing ratio of this second organic acid would be in the
range of 40 to 200% by weight based on the weight of the first
organic acid.
[0260] As explained above, the polishing cloth [polishing cloth
(1)] according to the present invention comprises an abrasive layer
containing a polymer material which is a hydrolyzable with an
aqueous medium.
[0261] As a polishing slurry containing abrasive grains and water
is fed to the polishing cloth constructed as described above with
this polishing cloth being kept rotating while pressing the subject
member onto the polishing cloth, the polishing surface of the
subject member is polished mainly by the abrasive grains in the
polishing slurry which has been fed to an interface between the
subject member and the polishing cloth. On this occasion, since the
polishing cloth contains a polymer material that is a hydrolyzable
with an aqueous medium, a region of the abrasive layer to which a
mechanical force is locally imparted by the sliding-contact under
pressure of subject member is permitted to hydrolyze and dissolve
by the water included in the polishing slurry being fed thereto,
thus enabling the surface of the polishing cloth to be always
renewed. Therefore, it is now possible to prevent the abrasive
grains in the polishing slurry from being accumulated and enlarged
on the surface (abrasive surface) of the polishing cloth. As a
result, the polishing cloth is enabled to exhibit a satisfactory
polishing performance which is almost equivalent to the initial
polishing performance (the polishing rate will be decreased more or
less as compared with that of the initial polishing period) for a
relatively long period of time without necessitating the
surface-regenerating operation that has been conventionally
performed after the polishing treatment and prior to the next
polishing treatment of the subject member by making use of a
dressing tool of dressing apparatus. Thus, it is now possible to
provide a polishing cloth which is capable of stably polishing a
subject member for a long period of time without necessitating a
dressing treatment.
[0262] In particular, when the polymer material constituting a main
component of the abrasive layer is formed of a homopolymer or a
copolymer each having a repeating unit of monomer represented by
the aforementioned formula (III) or (IV) (silyl acrylate or silyl
methacrylate) or formed of a homopolymer or a copolymer each having
a repeating unit of monomer represented by the aforementioned
formula (V) or (VI) (hemiacetal acrylate or hemiacetal
methacrylate), the solubility through hydrolysis of the polishing
cloth can be further enhanced, thus making it possible to further
improve the efficiency of renewal of the surface of polishing
cloth.
[0263] Namely, the homopolymer or the copolymer each having a
repeating unit of monomer represented by the aforementioned formula
(III), (IV), (V) or (VI) has a silyl ester group or hemiacetal
ester group each bonded to the backbone chain thereof, so that when
these esters hydrolyze, free hydrophilic carboxyl group is caused
to regenerate, thereby making it possible to more smoothly dissolve
the surface of the polishing cloth and hence further promote the
renewal of the surface of polishing cloth.
[0264] Further, when the particles of substance (for example,
rosin) which is higher in solubility than that of the polymer
material is dispersed in the polishing cloth, the dissolution
originating from each of the particles will be proceeded, thereby
making it possible to further promote the renewal of the surface of
polishing cloth.
[0265] Another kind of polishing cloth [polishing cloth (2)]
according to the present invention comprises an abrasive layer
containing a polymer material which is a hydrolyzable with an
aqueous medium and at least one abrasive grain selected from the
group consisting of cerium oxide, manganese oxide, silica, alumina
and zirconia, this abrasive grain being dispersed in the polymer
material.
[0266] As a polishing composition not containing water and abrasive
grain free is fed to the polishing cloth constructed as described
above with this polishing cloth being kept rotating while pressing
the subject member onto the polishing cloth, since the polishing
cloth contains a polymer material that is a hydrolyzable with an
aqueous medium, a region of the abrasive layer to which a
mechanical force is locally imparted by the sliding-contact under
pressure of subject member is hydrolyzed and eluted by the water
included in the polishing composition being fed thereto. As a
result, the abrasive grains that have been dispersed in the
polishing cloth are permitted to enter an interface between the
subject member and the polishing cloth, thus allowing the abrasive
grains to be automatically fed to the aforementioned interface to
thereby enable the polishing surface of the subject member to be
polished mainly by the abrasive grains. Further, since the
polishing cloth can be dissolved through the hydrolysis thereof and
the surface of the polishing cloth can be always renewed, it is now
possible to prevent the abrasive grains from being accumulated and
enlarged on the surface of the polishing cloth. As a result, the
polishing cloth is enabled to exhibit a satisfactory polishing
performance which is almost equivalent to the initial polishing
performance (the polishing rate will be decreased more or less as
compared with that of the initial polishing period) for a
relatively long period of time without necessitating the
surface-regenerating operation that has been conventionally
performed after the polishing treatment and prior to the next
polishing treatment of the subject member by making use of a
dressing tool of a dressing apparatus. Thus, it is now possible to
provide a polishing cloth which is capable of stably polishing a
subject member for a long period of time without necessitating a
dressing treatment.
[0267] In particular, when the polymer material constituting a main
component of the abrasive layer is formed of a homopolymer or a
copolymer each having a repeating unit of a monomer represented by
the aforementioned formula (III) or (IV) (silyl acrylate or silyl
methacrylate) or formed of a homopolymer or a copolymer each having
a repeating unit of monomer represented by the aforementioned
formula (V) or (VI) (hemiacetal acrylate or hemiacetal
methacrylate), the solubility through hydrolysis of the polishing
cloth can be further enhanced, thus making it possible to smoothly
feed the abrasive grains from the polishing cloth and, at the same
time, to further improve the efficiency of renewal of the surface
of the polishing cloth.
[0268] Further, when the particles of a substance (for example,
rosin) which is higher in solubility than that of the polymer
material are dispersed in the polishing cloth, the dissolution
originating from each of the particles will be proceeded, thereby
making it possible to more smoothly feed the abrasive grains from
the polishing cloth and, at the same time, to further promote the
renewal of the surface of the polishing cloth.
[0269] Another kind of polishing cloth [polishing cloth (3)]
according to the present invention comprises an abrasive layer
containing a polymer material which is a soluble in an aqueous
medium.
[0270] As a polishing slurry containing abrasive grains and water
is fed to the polishing cloth constructed as described above with
this polishing cloth being kept rotating while pressing the subject
member onto the polishing cloth, the polishing surface of the
subject member is polished mainly by the abrasive grains in the
polishing slurry which have been fed to an interface between the
subject member and the polishing cloth. On this occasion, since the
polishing cloth contains a polymer material that is a soluble in an
aqueous medium, a region of the abrasive layer to which a
mechanical force is locally imparted by the sliding-contact under
pressure of subject member is permitted to dissolve by the water
included in the polishing slurry being fed thereto, thus enabling
the surface of the polishing cloth to be always renewed. Therefore,
it is now possible to prevent the abrasive grains in the polishing
slurry from being accumulated and enlarged on the surface (abrasive
surface) of the polishing cloth. As a result, the polishing cloth
is enabled to exhibit a satisfactory polishing performance which is
almost equivalent to the initial polishing performance (the
polishing rate will be decreased more or less as compared with that
of the initial polishing period) for a relatively long period of
time without necessitating the surface-regenerating operation that
has been conventionally performed after the polishing treatment and
prior to the next polishing treatment of the subject member by
making use of a dressing tool of dressing apparatus. Thus, it is
now possible to provide a polishing cloth which is capable of
stably polishing a subject member for a long period of time without
necessitating a dressing treatment.
[0271] In particular, when the polymer material constituting a main
component of the abrasive layer is formed of a material that is a
soluble in an aqueous medium at a rate of 0.01 to 10.0 mg/min. as a
relative velocity between the abrasive layer and the subject member
to be polished is set to 1.0 m/sec. under a condition where the
subject member is permitted to contact the abrasive layer by
applying a load of 300 gf/cm.sup.2 to the subject member, the
solubility of the polishing cloth during the polishing procedure
can be further enhanced, thus making it possible to further improve
the efficiency of renewal of the surface of the polishing
cloth.
[0272] Another kind of polishing cloth [polishing cloth (4)]
according to the present invention comprises an abrasive layer
containing a polymer material which is a soluble in an aqueous
medium and at least one abrasive grain selected from the group
consisting of cerium oxide, manganese oxide, silica, alumina and
zirconia, this abrasive grain being dispersed in the polymer
material.
[0273] As a polishing composition not containing water and abrasive
grain free is fed to the polishing cloth constructed as described
above with this polishing cloth being kept rotating while pressing
the subject member onto the polishing cloth, since the polishing
cloth contains a polymer material that is a soluble in an aqueous
medium, a region of the abrasive layer to which a mechanical force
imparted by the slide-contact of the subject member is caused to
elute by the water included in the polishing composition being fed
thereto. As a result, the abrasive grains that have been dispersed
in the polishing cloth are permitted to enter an interface between
the subject member and the polishing cloth, thus allowing the
abrasive grains to be automatically fed to the aforementioned
interface to thereby enable the polishing surface of the subject
member to be polished mainly by the abrasive grains. Further, since
the polishing cloth can be dissolved in water and the surface of
the polishing cloth can be always renewed, it is now possible to
prevent the abrasive grains from being accumulated and enlarged on
the surface of the polishing cloth. As a result, the polishing
cloth is enabled to exhibit a satisfactory polishing performance
which is almost equivalent to the initial polishing performance
(the polishing rate will be decreased more or less as compared with
that of the initial polishing period) for a relatively long period
of time without necessitating the surface-regenerating operation
that has been conventionally performed after the polishing
treatment and prior to the next polishing treatment of the subject
member by making use of a dressing tool of dressing apparatus.
Thus, it is now possible to provide a polishing cloth which is
capable of stably polishing a subject member for a long period of
time without necessitating a dressing treatment.
[0274] In particular, when the polymer material constituting a main
component of the abrasive layer is formed of a material that is a
soluble in an aqueous medium at a rate of 0.01 to 10.0 mg/min. as a
relative velocity between the abrasive layer and the subject member
to be polished is set to 1.0 m/sec. under a condition where the
subject member is permitted to contact the abrasive layer by
applying a load of 300 gf/cm.sup.2 to the subject member, the
solubility of the polishing cloth during the polishing procedure
can be further enhanced, thus making it possible to more smoothly
feed the abrasive grains from the polishing cloth and, at the same
time, to further improve the efficiency of renewal of the surface
of the polishing cloth.
[0275] Another kind of polishing cloth [polishing cloth (5)]
according to the present invention comprises an abrasive layer, a
surface of which is prohibited from eluting in the presence of an
aqueous medium, until the abrasive layer is subjected to frictional
stress, and is permitted to elute in the presence of an aqueous
medium, when the abrasive layer is subjected to frictional
stress.
[0276] As a polishing slurry containing abrasive grains and water
is fed to the polishing cloth constructed as described above with
this polishing cloth being kept rotating while pressing the subject
member onto the polishing cloth, the polishing surface of the
subject member is polished mainly by the abrasive grains in the
polishing slurry which has been fed to an interface between the
subject member and the polishing cloth. On this occasion, a region
of the abrasive layer which is received a mechanical force
(frictional force or stress) imparted by pressurizing to subject
member and the slide-contact of the subject member is caused to
elute in the presence of the water included in the polishing slurry
being fed thereto, thus enabling the surface of the polishing cloth
to be always renewed. Therefore, it is now possible to prevent the
abrasive grains in the polishing slurry from being accumulated and
enlarged on the surface (abrasive surface) of the polishing cloth.
As a result, the polishing cloth is enabled to exhibit a
satisfactory polishing performance which is almost equivalent to
the initial polishing performance (the polishing rate will be
decreased more or less as compared with that of the initial
polishing period) for a relatively long period of time without
necessitating the surface-regenerating operation that has been
conventionally performed after the polishing treatment and prior to
the next polishing treatment of the subject member by making use of
a dressing tool of dressing apparatus. Thus, it is now possible to
provide a polishing cloth which is capable of stably polishing a
subject member for a long period of time without necessitating a
dressing treatment.
[0277] Another kind of polishing cloth [polishing cloth (6)]
according to the present invention comprises, at least on one side
thereof which is designed to be in contact with the subject member
to be polished, an abrasive layer having dispersed therein at least
one abrasive grain selected from the group consisting of cerium
oxide, manganese oxide, silica, alumina and zirconia. A surface
portion of the abrasive layer is prohibited from eluting in the
presence of an aqueous medium, until the abrasive layer is
subjected to frictional stress, and is permitted to elute in the
presence of an aqueous medium, when the abrasive layer is subjected
to frictional stress, concomitantly permitting the abrasive grain
to be supplied to the surface of the abrasive layer.
[0278] As a polishing composition not containing water and abrasive
grain free is fed to the polishing cloth constructed as described
above with this polishing cloth being kept rotating while pressing
the subject member onto the polishing cloth, a region of the
abrasive layer which is received a mechanical force (frictional
stress) imparted by pressurizing to the subject member and the
slide-contact of the subject member is caused to elute in the
presence of the water included in the polishing composition being
fed thereto. As a result, the abrasive grains that have been
dispersed in the polishing cloth are permitted to enter an
interface between the subject member and the polishing cloth, thus
allowing the abrasive grains to be automatically fed to the
aforementioned interface to thereby enable the polishing surface of
the subject member to be polished mainly by the abrasive grains.
Further, since the polishing cloth can be eluted in the presence of
water due to the effect of aforementioned frictional stress and the
surface of the polishing cloth can be always renewed, it is now
possible to prevent the abrasive grains from being accumulated and
enlarged on the surface of the polishing cloth. As a result, the
polishing cloth is enabled to exhibit a satisfactory polishing
performance which is almost equivalent to the initial polishing
performance (the polishing rate will be decreased more or less as
compared with that of the initial polishing period) for a
relatively long period of time without necessitating the
surface-regenerating operation that has been conventionally
performed after the polishing treatment and prior to the next
polishing treatment of the subject member by making use of a
dressing tool of a dressing apparatus. Thus, it is now possible to
provide a polishing cloth which is capable of stably polishing a
subject member for a long period of time without necessitating a
dressing treatment.
[0279] A polishing apparatus according to one embodiment of the
present invention comprises: a turntable having a surface which is
covered with a polishing cloth having an abrasive layer which is
constituted by any one of the aforementioned structures (1), (3)
and (5); holding means which is rotatively and vertically movably
disposed over the turntable and is designed to hold a subject
member to be polished, the holding means being also designed to
impose a desired magnitude of load on the subject member to thereby
enable the subject member to be press-contacted with the abrasive
cloth of the turntable, and further designed to rotate in the same
direction as that of the turntable; and feeding means for feeding a
polishing slurry containing abrasive grains to the polishing cloth.
Due to the effect of the abrasive cloth having any one of the
aforementioned structures (1), (3) and (5), this polishing
apparatus is capable of stably polishing a subject member for a
long period of time without necessitating a dressing treatment.
[0280] A polishing apparatus according to another embodiment of the
present invention comprises: a turntable having a surface which is
covered with a polishing cloth having an abrasive layer which is
constituted by any one of the aforementioned structures (2), (4)
and (6) and contains at least one kind of abrasive grain selected
from the group consisting of cerium oxide, manganese oxide, silica,
alumina and zirconia; holding means which is rotatively and
vertically movably disposed over the turntable and is designed to
hold a subject member to be polished, the holding means being also
designed to impose a desired magnitude of load on the subject
member to thereby enable the subject member to be press-contacted
with the abrasive cloth of the turntable, and further designed to
rotate in the same direction as that of the turntable; and feeding
means for feeding a polishing composition containing at least water
and abrasive grain free to the polishing cloth. Due to the effect
of the abrasive cloth having any one of the aforementioned
structures (2), (4) and (6), this polishing apparatus is capable of
automatically feeding abrasive grains to the polishing surface and
also capable of stably polishing a subject member for a long period
of time without necessitating a dressing treatment.
[0281] A method for manufacturing a polishing apparatus according
to another embodiment of the present invention comprises the steps
of: forming at least one embedding portion selected from a groove
corresponding to a configuration of a wiring layer and an opening
corresponding to a configuration of a via-fill in an insulating
film deposited on a semiconductor substrate; forming a wiring
material film made of copper or copper alloy on a surface of the
insulating film including the inner surface of the embedding
portion; and polishing the wiring material film by making use of a
polishing apparatus which is furnished therein with a polishing
cloth selected from any one of the aforementioned structures (1) to
(6), thereby forming at least one conductive member selected from a
wiring layer and a via-fill in the embedding portion.
[0282] According to this method, since the wiring material film is
designed to be polished by a simplified procedure employing a
polishing apparatus which is provided with a polishing cloth which
is capable of retaining a stable polishing performance without
necessitating the aforementioned dressing, it is now possible to
mass-produce a semiconductor device wherein a conductive member
such as a wiring layer having a desired film thickness is buried in
the embedding portion.
[0283] Next, examples of the present invention will be explained in
detail.
SYNTHESIS EXAMPLE 1
[0284] First of all, 40.0 parts by weight of xylene, and 10.0 parts
by weight of butyl acetate were introduced into a flask with a
stirrer, and the resultant mixture was heated up to a temperature
of 134.degree. C. Thereafter, a mixed solution comprising 60.0
parts by weight of tri-iso-propylsilyl acrylate (the compound
represented by the aforementioned formula (III-4)), 15.0 parts by
weight of 2-ethoxyethyl methacrylate, 20.0 parts by weight of
methyl methacrylate, 5.0 parts by weight of n-butyl methacrylate
and 1.0 part by weight of a polymerization catalyst or perbutyl I
(trade name, NOF CORPORATION; t-butyl peroxyisopropyl carbonate)
was added dropwise with stirring to the aforementioned mixture in
the flask over a period of 3 hours. After finishing this addition,
the resultant mixture was maintained at this temperature for 30
minutes to obtain a reaction mixture. Then, a mixture consisting of
10.0 parts by weight of xylene, and 1.0 part by weight of perbutyl
I was added dropwise to the aforementioned reaction mixture over a
period of 20 minutes, and the resultant mixture was stirred for 2
hours while maintaining this temperature to accomplish the
polymerization reaction. Finally, the resultant reaction mixture
was diluted by adding thereto 48.0 parts by weight of xylene to
obtain a 50% xylene solution of a copolymer having a repeating unit
of silyl acrylate having a structural formula represented by the
following formula (X).
[0285] Incidentally, the number average molecular weight of the
copolymer obtained in this manner was 67,000, and glass transition
temperature thereof was 56.degree. C. Further, the ratio of the
repeating unit of this silyl acrylate based on the entire weight of
this copolymer was 60% by weight. ##STR84##
[0286] (the composition ratios shown in this formula X are based on
weight %)<
SYNTHESIS EXAMPLE 2
[0287] First of all, 40.0 parts by weight of xylene, and 10.0 parts
by weight of butyl acetate were introduced into a flask with a
stirrer, and the resultant mixture was heated up to a temperature
of 134.degree. C. Thereafter, a mixed solution comprising 43.7
parts by weight of 1-iso-butoxyethyl methacrylate (the compound
represented by the aforementioned formula (VI-6)), 52.0 parts by
weight of methyl methacrylate, 4.3 parts by weight of 2-ethylhexyl
acrylate and 1.0 part by weight of a polymerization catalyst or
perbutyl I was added dropwise with stirring to the aforementioned
mixture in the flask over a period of 3 hours. After finishing this
addition, the resultant mixture was maintained at this temperature
for 30 minutes to obtain a reaction mixture. Then, a mixture
consisting of 10.0 parts by weight of xylene, and 1.0 part by
weight of perbutyl I was added dropwise to the aforementioned
reaction mixture over a period of 20 minutes, and the resultant
mixture was stirred for 2 hours while maintaining this temperature
to accomplish the polymerization reaction. Finally, the resultant
reaction mixture was diluted by adding thereto 48.0 parts by weight
of xylene to obtain a 50% xylene solution of a copolymer having a
repeating unit of hemiacetal methacrylate having a structural
formula represented by the following formula (XI).
[0288] Incidentally, the number average molecular weight of the
copolymer obtained in this manner was 38,000, and glass transition
temperature thereof was 50.degree. C. Further, the ratio of the
repeating unit of this hemiacetal methacrylate based on the entire
weight of this copolymer was 43.7% by weight. ##STR85##
[0289] (the composition ratios shown in this formula XI are based
on weight %)
SYNTHESIS EXAMPLE 3
[0290] First of all, 40.0 parts by weight of xylene, and 10.0 parts
by weight of butyl acetate were introduced into a flask with a
stirrer, and the resultant mixture was heated up to a temperature
of 134.degree. C. Thereafter, a mixed solution comprising 64.0
parts by weight of acrylic acid, 36.0 parts by weight of
methoxyethyl acrylate and 1.0 part by weight of a polymerization
catalyst or perbutyl I was added dropwise with stirring to the
aforementioned mixture in the flask over a period of 3 hours. After
finishing this addition, the resultant mixture was maintained at
this temperature for 30 minutes to obtain a reaction mixture. Then,
a mixture consisting of 10.0 parts by weight of xylene, and 1.0
part by weight of perbutyl I was added dropwise to the
aforementioned reaction mixture over a period of 20 minutes, and
the resultant mixture was stirred for 2 hours while maintaining
this temperature to accomplish the polymerization reaction.
[0291] Finally, the resultant reaction mixture was diluted by
adding thereto 48.0 parts by weight of xylene to obtain a 50%
xylene solution of a polymer which was soluble in an aqueous
medium.
[0292] Incidentally, the number average molecular weight of the
polymer obtained in this manner was 21,000, and glass transition
temperature thereof was 35.degree. C.
SYNTHESIS EXAMPLE 4
[0293] First of all, 40.0 parts by weight of xylene, and 10.0 parts
by weight of butyl acetate were introduced into a flask with a
stirrer, and the resultant mixture was heated up to a temperature
of 134.degree. C. Thereafter, a mixed solution comprising 15.0
parts by weight of methyl methacrylate acid, 85.0 parts by weight
of butyl methacrylate and 1.0 part by weight of a polymerization
catalyst or perbutyl I was added dropwise with stirring to the
aforementioned mixture in the flask over a period of 3 hours. After
finishing this addition, the resultant mixture was maintained at
this temperature for 30 minutes to obtain a reaction mixture. Then,
a mixture consisting of 10.0 parts by weight of xylene, and 1.0
part by weight of perbutyl I was added dropwise to the
aforementioned reaction mixture over a period of 20 minutes, and
the resultant mixture was stirred for 2 hours while maintaining
this temperature to accomplish the polymerization reaction.
[0294] Finally, the resultant reaction mixture was diluted by
adding thereto 48.0 parts by weight of xylene to obtain a 50%
xylene solution of a polymer, the surface of which was enabled to
elute in an aqueous medium as the polymer was subjected to a
frictional stress.
[0295] Incidentally, the number average molecular weight of the
polymer obtained in this manner was 17,000, and glass transition
temperature thereof was 44.degree. C.
EXAMPLE 1
[0296] Cerium oxide abrasive grains having an average particle
diameter of 0.2 .mu.m were dispersed in pure water at a ratio of
0.5% by weight to prepare a polishing slurry.
[0297] Further, a 50% xylene solution of the copolymer having a
structural formula represented by the formula (X) that had been
synthesized in the aforementioned Synthesis Example 1 was cast on
the surface of a turntable and then dried to obtain a polishing
cloth having a thickness of 50 .mu.m and constituted by the
aforementioned copolymer. The turntable covered with this polishing
cloth was then integrated into the aforementioned polishing
apparatus shown in FIG. 1.
[0298] Then, a 20 mm square silicon substrate having a silicon
oxide film formed thereon was prepared. Then, this silicon
substrate 6 was secured to the holder 5 of the polishing apparatus
shown in FIG. 1 in such a manner that the silicon oxide film
thereof faced the polishing cloth 2 formed on the surface of the
turntable 1. Thereafter, by means of the supporting shaft 4 of
holder 5, the wafer 6 made of contact the polishing cloth 2 formed
on the turntable 1 by applying a load of about 300 g/cm.sup.2 to
the wafer 6, while the turntable 1 and the holder 5 rotate in the
same direction with each other at a rotational speed of 100 rpm and
103 rpm, respectively, and the polishing slurry was fed from the
supply pipe 3 to the polishing cloth 2 at a flow rate of 20
mL/min., thereby polishing the silicon oxide film formed on the
surface of the silicon substrate 6 for a period of 60 minutes.
COMPARATIVE EXAMPLE 1
[0299] The silicon oxide film formed on the surface of the silicon
substrate 6 was polished for a period of 60 minutes under the same
conditions as described in Example 1 except that rigid polyurethane
foam (IC1000 (trade name); Rodel Co., Ltd.) was employed as a
polishing cloth to be integrated into the polishing apparatus.
[0300] The polishing time and the polishing rate of the silicon
oxide film in Example 1 as well as in Comparative Example 1 were
measured, the results being shown in FIG. 2.
[0301] As apparent from FIG. 2, in the case of Comparative Example
1 wherein the silicon oxide film formed on the silicon substrate
was polished using a polishing apparatus provided with the
conventional polishing cloth which was formed of rigid polyurethane
foam, the polishing rate was increased in proportion with the lapse
of polishing time. More specifically, the polishing rate was
increased by 30% over the initial polishing rate as the polishing
time was continued for 60 minutes, thus indicating the fluctuation
of the polishing rate.
[0302] By contrast, in the case of Example 1 wherein the silicon
oxide film formed on the silicon substrate was polished using a
polishing apparatus provided with a polishing cloth which was
formed of a copolymer having a structural formula shown in the
aforementioned formula (X), although the polishing rate was
increased more or less in proportion with the lapse of polishing
time, the polishing rate was increased only by 10% over the initial
polishing rate as the polishing time was continued for 60 minutes,
thus indicating a relatively stable polishing rate.
EXAMPLE 2
[0303] A 50% xylene solution of the copolymer having a structural
formula represented by the formula (XI) that had been synthesized
in the aforementioned Synthesis Example 2 was cast on the surface
of a turntable and then dried to obtain a polishing cloth having a
thickness of 50 .mu.m and constituted by the aforementioned
copolymer. The turntable covered with this polishing cloth was then
integrated into the aforementioned polishing apparatus shown in
FIG. 1.
[0304] Then, a 20 mm square silicon substrate having a silicon
oxide film formed thereon was prepared. Then, this silicon
substrate 6 was secured to the holder 5 of the polishing apparatus
shown in FIG. 1 in such a manner that the silicon oxide film
thereof faced the polishing cloth 2 formed on the surface of the
turntable 1. Thereafter, the silicon oxide film formed on the
surface of the silicon substrate 6 was polished in the same manner
as described in Example 1.
[0305] Further, the dressing for conditioning the state of the
surface of polishing cloth was performed by making use of a #80
diamond electrodeposition dresser and under the conditions of 200
g/cm.sup.2 in load and 160 rpm in rotational speed of the
turntable.
[0306] As a result, it was confirmed that it was possible, by
performing the aforementioned dressing for 5 minutes or more in
advance, to carry out a stable polishing of the silicon oxide film
at a polishing rate of about 40 nm/min.
EXAMPLE 3
[0307] A 50% xylene solution of the copolymer (a copolymer of
methyl methacrylate/butyl methacrylate) that had been synthesized
in the aforementioned Synthesis Example 4, i.e. the polymer whose
surface was eluted in an aqueous medium as it was subjected to a
frictional stress, was coated on the abrasive surface of
IC1000/Suba-400 (trade name, Rodel Co., Ltd.) and then dried to
obtain a polishing cloth having a thickness of 85 .mu.m. The
turntable covered with this polishing cloth was then integrated
into the aforementioned polishing apparatus shown in FIG. 1.
[0308] Then, a 20 mm square silicon substrate having a silicon
oxide film (P-TEOS film) formed thereon was prepared. Then, this
silicon substrate 6 was secured to the holder 5 of the polishing
apparatus shown in FIG. 1 in such a manner that the silicon oxide
film thereof faced the polishing cloth 2 formed on the surface of
the turntable 1. Thereafter, by means of the supporting shaft 4 of
holder 5, the wafer 6 was made to contact the polishing cloth 2
formed on the turntable 1 by applying a load of about 300
g/cm.sup.2 to the wafer 6, while the turntable 1 and the holder 5
were rotate in the same direction, at rotational speeds of 50 rpm
and 160 rpm, respectively, the polishing slurry comprising pure
water, and 1% by weight of cerium oxide abrasive grains having an
average particle diameter of 0.2 .mu.m and dispersed in pure water
was fed from the supply pipe 3 to the polishing cloth 2 at a flow
rate of 20 mL/min., thereby polishing the silicon oxide film formed
on the surface of the silicon substrate 6.
[0309] Further, the dressing for conditioning the state of the
surface of polishing cloth was performed by making use of a #80
diamond electrodeposition dresser and under the conditions of 200
g/cm.sup.2 in load and 160 rpm in rotational speed of the
turntable.
[0310] As a result, it was confirmed that it was possible, by
performing the aforementioned dressing for 5 minutes or more in
advance, to carry out a stable polishing of the silicon oxide film
at a polishing rate of about 40 nm/min.
EXAMPLE 4
[0311] A 50% xylene solution of the copolymer (a copolymer of
acrylic acid/methoxy acrylate) that had been synthesized in the
aforementioned Synthesis Example 3, i.e. the polymer which was
soluble in an aqueous medium, was coated on the abrasive surface of
IC1000/Suba-400 (trade name, Rodel Co., Ltd.) to a thickness of 55
.mu.m and then dried to obtain a polishing cloth. The turntable
covered with this polishing cloth was then integrated into the
aforementioned polishing apparatus shown in FIG. 1.
[0312] Then, a 25 mm square silicon substrate having a silicon
oxide film (P-TEOS film) formed thereon was prepared. Then, this
silicon substrate 6 was secured to the holder 5 of the polishing
apparatus shown in FIG. 1 in such a manner that the silicon oxide
film thereof faced the polishing cloth 2 formed on the surface of
the turntable 1. Thereafter, in the same manner as described in
Example 3, the silicon oxide film formed on the surface of the
silicon substrate 6 was polished.
[0313] Further, the dressing for conditioning the state of the
surface of polishing cloth was performed by making use of a #80
diamond electrodeposition dresser and under the conditions of 200
g/cm.sup.2 in load and 160 rpm in rotational speed of the
turntable.
[0314] As a result, it was confirmed that it was possible, by
performing the aforementioned dressing for 5 minutes or more in
advance, to carry out a stable polishing of the silicon oxide film
at a polishing rate of about 50 nm/min.
EXAMPLE 5
[0315] A 50% xylene solution of the copolymer that had been
synthesized in the aforementioned Synthesis Example 2, i.e. the
copolymer having a repeating unit of hemiacetal methacrylate, was
coated on the abrasive surface of IC1000/Suba-400 (trade name,
Rodel Co., Ltd.) to a thickness of 70 .mu.m and then dried to
obtain a polishing cloth. The turntable covered with this polishing
cloth was then integrated into the aforementioned polishing
apparatus shown in FIG. 1.
[0316] Then, a 25 mm square silicon substrate having a silicon
oxide film (P-TEOS film) formed thereon was prepared. Then, this
silicon substrate 6 was secured to the holder 5 of the polishing
apparatus shown in FIG. 1 in such a manner that the silicon oxide
film thereof faced the polishing cloth 2 formed on the surface of
the turntable 1. Thereafter, in the same manner as described in
Example 3, the silicon oxide film formed on the surface of the
silicon substrate 6 was polished.
[0317] Further, the dressing for conditioning the state of the
surface of polishing cloth was performed by making use of a #80
diamond electrodeposition dresser and under the conditions of 200
g/cm.sup.2 in load and 160 rpm in rotational speed of the
turntable.
[0318] As a result, it was confirmed that it was possible, by
performing the aforementioned dressing for 5 minutes or more in
advance, to carry out a stable polishing of the silicon oxide film
at a polishing rate of about 50 nm/min.
EXAMPLE 6
[0319] A 50% xylene solution of the copolymer having a repeating
unit of silyl acrylate and synthesized in the aforementioned
Synthesis Example 1, the xylene solution also containing 3% by
weight (based on the copolymer) of cerium oxide abrasive grains 0.2
.mu.m in average particle diameter, was coated on the abrasive
surface of IC1000/Suba-400 (trade name, Rodel Co., Ltd.) to a
thickness of about 50 .mu.m and then dried to obtain a polishing
cloth. The turntable covered with this polishing cloth was then
integrated into the aforementioned polishing apparatus shown in
FIG. 1.
[0320] Then, a 25 mm square silicon substrate having a silicon
oxide film (P-TEOS film) formed thereon was prepared. Then, this
silicon substrate 6 was secured to the holder 5 of the polishing
apparatus shown in FIG. 1 in such a manner that the silicon oxide
film thereof faces the polishing cloth 2 formed on the surface of
the turntable 1. Thereafter, by means of the supporting shaft 4 of
holder 5, the silicon substrate 6 was made to contact the polishing
cloth 2 formed on the turntable 1 by applying a load of about 300
g/cm.sup.2 to the silicon substrate 6, while the turntable 1 and
the holder 5 were rotated in the same direction, at rotational
speeds of 50 rpm and 160 rpm, respectively, a 4.3 wt % aqueous
solution of hydrogen peroxide (polishing composition) was fed from
the supply pipe 3 to the polishing cloth 2 at a flow rate of 20
mL/min., thereby polishing the silicon oxide film formed on the
surface of the silicon substrate 6.
[0321] Further, the dressing for conditioning the state of the
surface of polishing cloth was performed by making use of a #80
diamond electrodeposition dresser and under the conditions of 200
g/cm.sup.2 in load and 160 rpm in rotational speed of the
turntable.
[0322] As a result, it was confirmed that, in spite of the fact
that the polishing composition contained no abrasive grain, it was
possible, by performing the dressing for 10 seconds in advance, to
carry out the polishing of the silicon oxide film at a polishing
rate of about 4 nm/min.
EXAMPLE 7
[0323] A 50% xylene solution of the copolymer having a repeating
unit of silyl acrylate and synthesized in the aforementioned
Synthesis Example 1, the xylene solution also having dispersed
therein 3% by weight (based on the copolymer) of alumina abrasive
grains 0.6 .mu.m in average particle diameter, was coated on the
abrasive surface of IC1000/Suba-400 (trade name, Rodel Co., Ltd.)
to a thickness of about 50 .mu.m and then dried to obtain a
polishing cloth. The turntable covered with this polishing cloth
was then integrated into the aforementioned polishing apparatus
shown in FIG. 1.
[0324] Then, a 25 mm square silicon substrate having a copper film
formed thereon was prepared. Then, this silicon substrate 6 was
secured to the holder 5 of the polishing apparatus shown in FIG. 1
in such a manner that the copper film thereof faced the polishing
cloth 2 formed on the surface of the turntable 1. Thereafter, by
means of the supporting shaft 4 of holder 5, the silicon substrate
6 was made to contact the polishing cloth 2 formed on the turntable
1 by applying a load of about 300 g/cm.sup.2 to the silicon
substrate 6, while the turntable 1 and the holder 5 were rotated in
the same direction, at rotational speeds of 50 rpm and 160 rpm,
respectively, a polishing composition was fed from the supply pipe
3 to the polishing cloth 2 at a flow rate of 20 mL/min., thereby
polishing the copper film formed on the surface of the silicon
substrate 6. Incidentally, the polishing composition employed
herein was formed of an aqueous solution comprising 0.5% by weight
of quinaldinic acid, 0.6% by weight of lactic acid, 0.9% by weight
of a surfactant and 4.5% by weight of hydrogen peroxide.
[0325] Further, the dressing for conditioning the state of the
surface of polishing cloth was performed by making use of a #80
diamond electrodeposition dresser and under the conditions of 200
g/cm.sup.2 in load and 160 rpm in rotational speed of the
turntable.
[0326] As a result, it was confirmed that, in spite of the fact
that the polishing composition contained no abrasive grain, it was
possible, by performing the dressing for 10 seconds in advance, to
carry out the polishing of the copper film at a polishing rate of
about 11 nm/min.
EXAMPLE 8
[0327] First of all, a polishing slurry consisting of 3.6% by
weight of colloidal silica, 1.1% by weight of colloidal alumina,
0.6% by weight of 2-quinoline carboxylic acid (quinaldinic acid),
0.35% by weight of lactic acid, 1.8% by weight of ammonium dodecyl
sulfate, 3.9% by weight of hydrogen peroxide, 0.5% by weight of
hydroxyethyl cellulose and the balance of water was prepared.
[0328] Then, by means of CVD method, an SiO.sub.2 film 22 having a
thickness of 1000 nm for example was deposited as an interlayer
insulating film on the surface of a silicon substrate 21 provided
on the surface thereof with diffusion layers such as source and
drain as shown in FIG. 3A. Thereafter, by means of photoetching
technique, a plurality of grooves 23 each having a width of 100
.mu.m, a depth of 0.8 .mu.m and a configuration corresponding to a
wiring layer were formed. Furthermore, as shown in FIG. 3B, by
means of sputter deposition method, a barrier layer 24 made of TiN
and having a thickness of 15 nm as well as a Cu film 25 having a
thickness of 1.6 .mu.m were successively formed in the mentioned
order all over the surface of the SiO.sub.2 film 22 including the
surface of aforementioned grooves.
[0329] Thereafter, by making use of a polishing apparatus as shown
in FIG. 1 which is provided with a turntable having its surface
covered with a 0.8 mm thick polishing cloth formed of a copolymer
having the same structural formula as employed in Example 1, i.e.
the formula (X), a silicon substrate 21 having a Cu film 25 formed
thereon was reversely secured to the holder 5 of the polishing
apparatus in such a manner that the Cu film 25 thereof faced the
polishing cloth 2 formed on the surface of the turntable 1.
Thereafter, by means of the supporting shaft 4 of holder 5, the
silicon substrate 21 was pressed onto the polishing cloth 2 formed
on the turntable 1 by applying a load of about 500 gf/cm.sup.2 to
the silicon substrate 21, while the turntable 1 and the holder 5
were rotated in the same direction, at rotational speeds of 103 rpm
and 100 rpm, respectively, the polishing slurry was fed from the
supply pipe 3 to the polishing cloth 2 at a flow rate of 50
mL/min., thereby polishing the Cu film 25 film and the barrier
layer 24 for a period of about 40 minutes until the SiO.sub.2 film
22 and the barrier layer 24 were exposed, thus forming a buried Cu
wiring layer 26 which was enclosed by the barrier layer 24 as shown
in FIG. 3C. As a result, a semiconductor device having the buried
Cu wiring layer 26 was manufactured.
[0330] As explained above, it is now possible according to the
present invention to provide a polishing cloth which is capable of
exhibiting a stable polishing performance for a relatively long
period of time without necessitating a dressing treatment.
[0331] It is also possible according to the present invention to
provide a polishing cloth which is provided with an automatic
abrasive grain-feeding capability and capable of exhibiting a
stable polishing performance for a relatively long period of time
without necessitating a dressing treatment.
[0332] It is further possible according to the present invention to
provide a polishing apparatus provided with aforementioned cloth
which is capable of exhibiting a stable polishing performance and
suited for use in a chemical mechanical polishing (CMP) for forming
a buried conductive member such as an embedded wiring layer of a
semiconductor device.
[0333] It is further possible according to the present invention to
provide a method of manufacturing a semiconductor device, which
makes it possible to reliably form a conductive member such as a
buried wiring layer with high precision in at least one embedding
portion selected from groove and opening formed in an insulating
film which has been deposited on a semiconductor substrate.
* * * * *