U.S. patent application number 11/540835 was filed with the patent office on 2007-04-05 for polishing composition and polishing method.
Invention is credited to Takashi Ito, Yoshio Kimura.
Application Number | 20070074457 11/540835 |
Document ID | / |
Family ID | 37671391 |
Filed Date | 2007-04-05 |
United States Patent
Application |
20070074457 |
Kind Code |
A1 |
Ito; Takashi ; et
al. |
April 5, 2007 |
Polishing composition and polishing method
Abstract
A polishing composition contains silica abrasive grains having
an average particle size of 20 to 100 nm, an alkali selected from
the group consisting of ammonia, ammonium salts, alkali metal
salts, and alkali metal hydroxides, and a silicone oil having an
HLB value greater than or equal to 8. The polishing composition is
suitable for use in an application for polishing an object to be
polished.
Inventors: |
Ito; Takashi; (Gifu-shi,
JP) ; Kimura; Yoshio; (Jhubei City, TW) |
Correspondence
Address: |
VIDAS, ARRETT & STEINKRAUS, P.A.
6109 BLUE CIRCLE DRIVE
SUITE 2000
MINNETONKA
MN
55343-9185
US
|
Family ID: |
37671391 |
Appl. No.: |
11/540835 |
Filed: |
September 29, 2006 |
Current U.S.
Class: |
51/308 ;
257/E21.244 |
Current CPC
Class: |
H01L 21/31053 20130101;
C09G 1/02 20130101 |
Class at
Publication: |
051/308 |
International
Class: |
B24D 3/02 20060101
B24D003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 30, 2005 |
JP |
2005-289169 |
Claims
1. A polishing composition used in an application for polishing an
object to be polished comprising silicon dioxide, the polishing
composition comprising: silica abrasive grains having an average
particle size of 20 to 100 nm; an alkali selected from the group
consisting of ammonia, ammonium salts, alkali metal salts, and
alkali metal hydroxides; and a silicone oil having an HLB value
greater than or equal to 8.
2. The polishing composition according to claim 1, wherein the
molecular weight of the silicone oil is 200 to 20,000.
3. The polishing composition according to claim 1, wherein the
silicone oil is a polyether modified silicone oil.
4. A polishing method comprising polishing an object to be polished
comprising silicon dioxide using the polishing composition
according to claim 1.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a polishing composition
which is used, for example, in an application for polishing an
object to be polished comprising silicon dioxide such as SiO.sub.2
film as an insulating film in a semiconductor circuit, and a
polishing method using such a polishing composition.
[0002] A polishing composition used in an application for polishing
an object to be polished comprising silicon dioxide such as
SiO.sub.2 film is required to have at least properties of causing
few defects such as scratches resulting on the surface of an object
to be polished when the object to be polished is polished using the
polishing composition, and a high polishing rate (a high removal
rate) for the object to be polished by the polishing composition.
For example, a polishing composition improved for satisfying such
requirements and containing silica abrasive grains such as fumed
silica and a thickener such as polyacrylic resin is disclosed in
Japanese Laid-Open Patent Publication No. 2001-271058. However, the
polishing composition of Japanese Laid-Open Patent Publication No.
2001-271058 does not satisfy the requirements enough and has still
room to be improved.
[0003] Meanwhile, a polishing composition containing a silicone
surfactant such as polyoxyethylene methylpolysiloxane is disclosed
in Japanese Laid-Open Patent Publication No. 2004-247605. However,
the polishing composition of Japanese Laid-Open Patent Publication
No. 2004-247605 is used in an application for polishing an object
to be polished including an organic insulating film, and use in an
application for polishing an object to be polished comprising
silicon dioxide such as SiO.sub.2 film is not aimed at.
SUMMARY OF THE INVENTION
[0004] Accordingly, it is an objective of the present invention to
provide a polishing composition suitable for use in an application
for polishing an object to be polished comprising silicon dioxide
and a polishing method using such a polishing composition.
[0005] To achieve the foregoing objectives and in accordance with a
first aspect of the present invention, a polishing composition used
in an application for polishing an object to be polished comprising
silicon dioxide is provided. The polishing composition contains
silica abrasive grains having an average particle size of 20 to 100
nm, an alkali selected from the group consisting of ammonia,
ammonium salts, alkali metal salts, and alkali metal hydroxides,
and a silicone oil having an HLB value greater than or equal to
8.
[0006] In accordance with a second aspect of the present invention,
a polishing method including polishing an object to be polished
comprising silicon dioxide using the polishing composition is
provided.
[0007] Other aspects and advantages of the invention will become
apparent from the following description, illustrating by way of
example the principles of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0008] Hereinbelow, an embodiment of the present invention is
described.
[0009] A polishing composition according to this embodiment is
produced by mixing silica abrasive grains, alkali, silicone oil,
and water. Accordingly, the polishing composition substantially
consists of silica abrasive grains, alkali, silicone oil, and
water. The polishing composition is used in an application for
polishing, for example, SiO.sub.2 film as an insulating film of a
semiconductor circuit.
[0010] Silica abrasive grains in the polishing composition play a
role of mechanically polishing SiO.sub.2 film and contribute to
improving the polishing rate (removal rate) of SiO.sub.2 film by
the polishing composition.
[0011] Silica abrasive grains contained in the polishing
composition are preferably fumed silica or colloidal silica, and
more preferably they are fumed silica. When silica abrasive grains
contained in the polishing composition are fumed silica or
colloidal silica, scratches resulting on the surface of SiO.sub.2
film when the SiO.sub.2 film is polished using a polishing
composition are reduced. In addition to the reduction of scratches,
polishing rate of SiO.sub.2 film by the polishing composition is
significantly improved as well when silica abrasive grains
contained in the polishing composition are fumed silica.
[0012] The average particle size of silica abrasive grains
contained in the polishing composition is 20 to 100 nm. When the
average particle size of silica abrasive grains contained in the
polishing composition is less than 20 nm, not only polishing rate
of SiO.sub.2 film by the polishing composition is not significantly
improved but also scratches resulting on the surface of SiO.sub.2
film when the SiO.sub.2 film is polished using a polishing
composition increase. On the other hand, silica abrasive grains
having an average particle size more than 100 nm are poor in
dispersibility in the polishing composition and easy to be
deposited. In addition, the surface roughness of SiO.sub.2 film
obtained by polishing it with a polishing composition may increase
when the average particle size of silica abrasive grains contained
in the polishing composition is more than 100 nm.
[0013] But when the average particle size of silica abrasive grains
contained in the polishing composition is less than 25 nm, even if
it is greater than or equal to 20 nm, polishing rate of SiO.sub.2
film by the polishing composition is slightly in short, and
scratches resulting on the surface of SiO.sub.2 film increase a
little. Therefore, it is preferable for improving the polishing
rate and for reduction of scratches that the average particle size
of silica abrasive grains contained in the polishing composition is
greater than or equal to 25 nm. In addition, silica abrasive grains
having an average particle size more than 75 nm are slightly poor
in dispersibility in the polishing composition even if it is less
than or equal to 100 nm. Therefore, it is preferable for the
improvement of dispersibility of silica abrasive grains that the
average particle size of silica abrasive grains contained in the
polishing composition is less than or equal to 75 nm. The average
particle size of silica abrasive grains is calculated by specific
surface area of silica abrasive grains measured by BET method.
[0014] When the content of silica abrasive grains in the polishing
composition is less than 1% by mass, or even when it is less than
5% by mass, polishing rate of SiO.sub.2 film by the polishing
composition is not improved significantly. Therefore, it is
preferable for the improvement of polishing rate that the content
of silica abrasive grains in the polishing composition is greater
than or equal to 1% by mass, and more preferably it is greater than
or equal to 5% by mass. On the other hand, when the content of
silica abrasive grains in the polishing composition is more than
40% by mass, or even when it is more than 20% by mass, there is a
possibility that dispersibility of silica abrasive grains in the
polishing composition decreases, and aggregation of silica abrasive
grains or gelation of the polishing composition may occur.
Therefore, it is preferable for the improvement of dispersibility
of silica abrasive grains that the content of silica abrasive
grains in the polishing composition is less than or equal to 40% by
mass, and more preferably it is less than or equal to 20% by
mass.
[0015] Alkali in the polishing composition plays a role of
chemically polishing SiO.sub.2 film, and contributes to improvement
of polishing rate of SiO.sub.2 film by the polishing
composition.
[0016] Alkali contained in the polishing composition is ammonia,
ammonium salt, alkali metal salt, or alkali metal hydroxide.
Ammonium salt contained in the polishing composition may be
ammonium carbonate, and alkali metal salt contained in the
polishing composition may be an alkaline metal carbonate. Alkali
metal hydroxide contained in the polishing composition may be
sodium hydroxide, potassium hydroxide or lithium hydroxide.
Meanwhile, when the alkali contained in the polishing composition
is a compound other than ammonia, ammonium salt, alkali metal salt
and alkali metal hydroxide, such as tetramethylammonium hydroxide
(TMAH), the polishing rate of SiO.sub.2 film by the polishing
composition is not significantly improved. Therefore, scratches
resulting on the surface of SiO.sub.2 film when the SiO.sub.2 film
is polished with a polishing composition is greatly increased.
[0017] When the content of alkali in the polishing composition is
less than 0.01% by mass, or even when it is less than 0.1% by mass,
the polishing rate of SiO.sub.2 film by the polishing composition
is not significantly improved. Therefore, it is preferable for the
improvement of polishing rate that the content of alkali in the
polishing composition is greater than or equal to 0.01% by mass,
and more preferably it is greater than or equal to 0.1% by mass. On
the other hand, when the content of alkali in the polishing
composition is more than 10% by mass, there is a possibility that
silica abrasive grains in the polishing composition may dissolve.
Therefore, it is preferable for the prevention of dissolution of
silica abrasive grains that the content of alkali in the polishing
composition is less than or equal to 10% by mass.
[0018] Silicone oil in the polishing composition has an effect of
reducing scratches resulting on the surface of SiO.sub.2 film when
the SiO.sub.2 film is polished with the polishing composition. It
is inferred that this effect comes from protective coatings formed
by silicone oil on the surfaces of silica abrasive grains and the
surface of the SiO.sub.2 film. More specifically, it is inferred
that when protective coatings are formed by the silicone oil on the
surfaces of silica abrasive grains, and as a result aggregation of
silica abrasive grains is suppressed and scratches by aggregated
silica abrasive grains are suppressed. In addition, it is inferred
that when a protective coating is formed by the silicone oil on the
surface of the SiO.sub.2 film, scratches by polishing waste are
also suppressed by the protective coating.
[0019] Silicone oil contained in the polishing composition may be a
straight silicone oil or a modified silicone oil. Modified silicone
oil includes reactive silicone oil such as amino modified silicone
oil, carboxyl modified silicone oil, and heterologous functional
group modified silicone oil, and non-reactive silicone oil such as
polyether modified silicone oil, higher fatty acid ester modified
silicone oil, and hydrophilic specially modified silicone oil.
Among all, the silicone oil contained in the polishing composition
is preferably a polyether modified silicone oil by which an
appropriate HLB (hydrophilic-lipophilic balance) value is easy to
be obtained. The polyether modified silicone oil as a silicone oil
contained in the polishing composition may be a side-chain type in
which a polyoxyalkylene group is introduced in a part of side
chains of polysiloxane or a both-end type in which polyoxyalkylene
groups are introduced in the both ends of polysiloxane.
Alternativley, it may be a single-end type in which a
polyoxyalkylene group is introduced in one end of polysiloxane or a
side-chain-both-end type in which polyoxyalkylene groups are
introduced in a part of side chains of polysiloxane and the both
ends of polysiloxane.
[0020] When the content of the silicone oil in the polishing
composition is less than 1 ppm, or even when it is less than 10
ppm, or yet even when it is less than 100 ppm, scratches resulting
on the surface of SiO.sub.2 film when the SiO.sub.2 film is
polished with the polishing composition are not significantly
reduced. Therefore, it is preferable for reduction of scratches
that the content of the silicone oil in the polishing composition
is greater than or equal to 1 ppm, more preferably it is greater
than or equal to 10 ppm, and the most preferably it is greater than
or equal to 100 ppm. On the other hand, there is a possibility that
polishing of SiO.sub.2 film may be suppressed by the protective
coating of silicone oil formed on the surface of the SiO.sub.2 film
when the content of the silicone oil in the polishing composition
is more than 10,000 ppm, or even when it is more than 5,000 ppm, or
further even when it is more than 1,000 ppm. And as a result, there
is a possibility that polishing rate of SiO.sub.2 film by the
polishing composition decreases. Therefore, it is preferable for
the prevention of decrease in the polishing rate that the content
of silicone oil in the polishing composition is less than or equal
to 10,000 ppm, and more preferably it is less than or equal to
5,000 ppm, and the most preferably it is less than or equal to
1,000 ppm.
[0021] HLB value of the silicone oil contained in the polishing
composition is greater than or equal to 8. When the HLB value of
the silicone oil contained in the polishing composition is less
than 8, organic residual substances derived from the silicone oil
tend to remain as extraneous substances on the surface of SiO.sub.2
film polished with the polishing composition.
[0022] But when the HLB value of silicone oil contained in the
polishing composition is less than 9, or even when it is less than
10, even in the case that it is greater than or equal to 8, organic
residual substances derived from the silicone oil tend to remain as
extraneous substances on the surface of SiO.sub.2 film polished
with the polishing composition. Therefore, it is preferable for
reliably suppressing remaining of extraneous substances on the
SiO.sub.2 film that the HLB value of the silicone oil contained in
the polishing composition is greater than or equal to 9, and more
preferably it is greater than or equal to 10. On the other hand,
the polishing composition is easy to cause foaming when the HLB
value of the silicone oil contained in the polishing composition is
greater than or equal to 16, or even when it is greater than or
equal to 12. Therefore, it is preferable for improving defoaming
properties of the polishing composition that the HLB value of the
silicone oil contained in the polishing composition is less than
16, and more preferably it is less than 12.
[0023] It is preferable for effective reduction of defects such as
scratches resulting on the surface of SiO.sub.2 film when the
SiO.sub.2 film is polished with the polishing composition that the
average molecular weight of the silicone oil contained in the
polishing composition is 200 to 10,000.
[0024] Surface tension of the polishing composition decreases by
the addition of silicone oil. The surface tension of the polishing
composition is preferably less than 60 mN/m to effectively reduce
defects such as scratches resulting on the surface of SiO.sub.2
film when the SiO.sub.2 film is polished with the polishing
composition.
[0025] According to this embodiment, the following advantages are
obtained.
[0026] Since the polishing composition of the present embodiment
contains silicone oil having an effect of reducing scratches
resulting on the surface of SiO.sub.2 film, the polishing
composition enables to reduce scratches resulting on the surface of
SiO.sub.2 film when the SiO.sub.2 film is polished with the
polishing composition. Besides, since the HLB value of silicone oil
contained in the polishing composition is greater than or equal to
8, it suppresses formation of organic residue as extraneous
substances derived from the silicone oil on the surface of
SiO.sub.2 film polished with the polishing composition. In
addition, since the polishing composition comprises silica abrasive
grains having a role of mechanically polishing SiO.sub.2 film and
alkali having a role of chemically polishing SiO2 film, the
polishing composition polish SiO.sub.2 film at a high polishing
rate. Therefore, according to the present embodiment, a polishing
composition suitable for use in an application for polishing
SiO.sub.2 film is provided.
[0027] The average particle size of silica abrasive grains
contained in the polishing composition is 20 to 100 nm. Therefore,
according to the present embodiment, increase of scratches on the
surface of SiO.sub.2 film which will occur when the average
particle size of silica abrasive grains is less than 20 nm and
increase of surface roughness of SiO.sub.2 film which will occur
when the average particle size of silica abrasive grains is greater
than 100 nm are prevented.
[0028] Alkali contained in the polishing composition is not
tetramethylammonium hydroxide but ammonia, ammonium salt, alkali
metal salt or alkali metal hydroxide. Therefore, scratches
resulting on the surface of SiO.sub.2 film will not be greatly
increased by the effect of alkali.
[0029] The above embodiment may be changed as follows.
[0030] Two or more kinds of silica abrasive grains may be contained
in the polishing composition of the above embodiment.
[0031] Two or more kinds of alkalis may be contained in the
polishing composition of the above embodiment.
[0032] Two or more kinds of silicone oils may be contained in the
polishing composition of the above embodiment. That is, for
example, polyether modified silicone oil and silicone oil other
than that may be contained in the polishing composition. However,
silicone oil contained in the polishing composition is preferably
only polyether modified silicone oil since suitable HLB value is
easy to be obtained in that composition. In addition, the value of
weighted average of HLB values of each silicone oil in the
polishing composition must be greater than or equal to 8 when more
than two kinds of silicone oil are contained in the polishing
composition.
[0033] Mildewproofing agents, anticorrosives, defoaming agents,
chelating agents, etc. may be added in the polishing composition of
the above embodiment if necessary.
[0034] The polishing composition of the above embodiment may be
used in an application for polishing an object to be polished
comprising silicon dioxide other than SiO.sub.2 film.
[0035] The polishing composition of the above embodiment may be
prepared by diluting a stock solution of the polishing composition
with water.
[0036] Examples of the present invention and Comparative Examples
are described below.
[0037] Polishing compositions of Examples 1-21 and Comparative
Examples 1-6 were prepared by mixing silica abrasive grains,
alkali, polyether modified silicone oil of side-chain type, and
water appropriately. Details of silica abrasive grains, alkali, and
polyether modified silicone oil in the polishing compositions of
Example 1-21 and Comparative Examples 1-6 and surface tensions for
the polishing compositions of Examples 1-9 and Comparative Examples
1-3 are as shown in Table 1. Here, surface tension for each
polishing composition was measured under measurement conditions
shown in Table 2.
[0038] The "polishing rate" column of Table 1 shows polishing rates
obtained when an SiO.sub.2 blanket wafer (a wafer with a TEOS film)
having a diameter of 200 mm is polished with each of the polishing
compositions of Examples 1-21 and Comparative Examples 1-6 under
polishing conditions shown in Table 3. The polishing rate was
determined by dividing the difference in the thickness of each
wafer before and after polishing by the polishing time. Film
thickness measuring apparatus "VM2030" of Dainippon Screen Mfg.
Co., Ltd. was used for the measurement of a thickness of a
wafer.
[0039] In the "surface defects" column of Table 1, results of
evaluating surface defects of SiO.sub.2 blanket wafers polished
under polishing conditions shown in Table 3 using each of the
polishing compositions of Examples 1-21 and Comparative Examples
1-6 are shown. Specifically, SiO.sub.2 blanket wafers polished with
each of the polishing compositions were washed with 0.5% by mass
hydrofluoric acid solution for 12 seconds, and subsequently the
number of scratches and extraneous substances having a size greater
than or equal to 0.2 .mu.m present on the surface of SiO.sub.2
blanket wafer was measured using wafer tester "SURFSCAN SP1-TBI" of
KLA-Tencor Corporation. In the "surface defects" column, "1"
(excellent) shows that the number of scratches and extraneous
substances having a size greater than or equal to 0.2 .mu.m was
less than 10, "2" (good) shows that the number was not less than 10
and less than 30, "3" (slightly poor) shows that the number was not
less than 30 and less than 50 and "4" (poor) shows that the number
was not less than 50.
[0040] In the "defoaming properties" column of Table 1, results of
evaluating defoaming properties of each of the polishing
compositions of Examples 1-21 and Comparative Examples 1-6 are
shown. Specifically, about 80 mL each of the polishing compositions
was put in glass vessels having a volume of 100 mL and shaken for
10 seconds and the length of time needed after shaking before foams
almost disappeared in the polishing composition was measured. In
the "defoaming properties" column, "1" (excellent) shows that the
length of time before foams disappeared was less than 1 minute, "2"
(good) shows that the length of time was not less than 1 minute and
less than 5 minutes, "3" (slightly poor) shows that the length of
time was not less than 5 minutes and less than 10 minutes and "4"
(poor) shows that the length of time was not less than 10 minutes.
TABLE-US-00001 TABLE 1 Polyether modified silicone oil Silica
abrasive grains Alkali Average Surface Content Content Content
molecular tension Polishing rate Surface Defoaming Type [% by mass]
Type [% by mass] [% by mass] HLB weight [mN/m] [A/min] defects
properties C. Ex. 1 Fumed silica*.sup.1 12.5 NH.sub.3 0.5 0 -- --
69.6 2655 3 1 C. Ex. 2 Fumed silica*.sup.1 12.5 NH.sub.3 0.5 100 4
1000 23.1 2185 4 1 C. Ex. 3 Fumed silica*.sup.1 12.5 NH.sub.3 0.5
100 7 6000 29.8 2524 3 1 Ex. 1 Fumed silica*.sup.1 12.5 NH.sub.3
0.5 100 10 3000 35.1 2478 1 2 Ex. 2 Fumed silica*.sup.1 12.5
NH.sub.3 0.5 100 12 1000 26.9 2263 1 3 Ex. 3 Fumed silica*.sup.1
12.5 NH.sub.3 0.5 100 12 200 44.0 2175 1 3 Ex. 4 Fumed
silica*.sup.1 12.5 NH.sub.3 0.5 100 16 15000 62.2 2177 2 4 Ex. 5
Fumed silica*.sup.1 12.5 NH.sub.3 0.5 10 10 3000 59.4 2661 2 1 Ex.
6 Fumed silica*.sup.1 12.5 NH.sub.3 0.5 50 10 3000 30.0 2539 2 1
Ex. 7 Fumed silica*.sup.1 12.5 NH.sub.3 0.5 200 10 3000 33.0 2315 1
2 Ex. 8 Fumed silica*.sup.1 12.5 NH.sub.3 0.5 500 10 3000 28.4 2181
1 2 Ex. 9 Fumed silica*.sup.1 12.5 NH.sub.3 0.5 1000 10 3000 35.1
2033 1 2 Ex. 10 Fumed silica*.sup.1 12.5 NH.sub.3 0.3 100 10 3000
-- 2571 1 2 Ex. 11 Fumed silica*.sup.1 12.5 NH.sub.3 0.75 100 10
3000 -- 2739 1 2 Ex. 12 Fumed silica*.sup.1 12.5 NH.sub.3 1.2 100
10 3000 -- 2879 1 2 Ex. 13 Fumed silica*.sup.1 12.5 KOH 0.5 100 10
3000 -- 3034 1 2 Ex. 14 Fumed silica*.sup.1 12.5 KOH 1.0 100 10
3000 -- 3355 1 2 C. Ex. 4 Fumed silica*.sup.1 12.5 TMAH 0.5 100 10
3000 -- 354 3 2 C. Ex. 5 Fumed silica*.sup.1 12.5 TMAH 1.0 100 10
3000 -- 118 4 2 Ex. 15 Fumed silica*.sup.1 5 NH.sub.3 0.5 100 10
3000 -- 547 1 2 Ex. 16 Fumed silica*.sup.1 8 NH.sub.3 0.5 100 10
3000 -- 1834 1 2 Ex. 17 Fumed silica*.sup.1 18 NH.sub.3 0.5 100 10
3000 -- 3367 1 2 Ex. 18 Fumed silica*.sup.1 25 NH.sub.3 0.5 100 10
3000 -- 3339 2 2 Ex. 19 Fumed silica*.sup.2 12.5 NH.sub.3 0.5 100
10 3000 -- 2916 1 2 C. Ex. 6 Colloidal silica*.sup.1 11 NH.sub.3
0.5 100 10 3000 -- 377 4 2 Ex. 20 Colloidal silica*.sup.2 12.5
NH.sub.3 0.5 100 10 3000 -- 546 2 2 Ex. 21 Colloidal silica*.sup.3
12.5 NH.sub.3 0.5 100 10 3000 -- 1299 1 2
[0041] In "Silica abrasive grains" column of Table 1, "Fumed
silica*.sup.1" represents fumed silica having an average particle
size of 30 nm and "Fumed silica*.sup.2" represents fumed silica
having an average particle size of 50 nm, and "Colloidal
silica*.sup.1" represents colloidal silica having an average
particle size of 10 nm, "Colloidal silica*.sup.2" represents
colloidal silica having an average particle size of 30 nm and
"Colloidal silica*.sup.3" represents colloidal silica having an
average particle size of 90 nm. TABLE-US-00002 TABLE 2 Measuring
apparatus: Automatic surface tension meter "CBVP-Z" of Kyowa
InterFace Science Co., Ltd. Measuring method: Plate method Probe:
Platinum plate Measurement temperature: 25.degree. C.
[0042] TABLE-US-00003 TABLE 3 Polishing device: CMP device
"EPO-113D" of Ebara Corporation Polishing load: 34.5 kPa (5.0 psi)
Polishing linear velocity: 42 m/min Polishing time: 30 seconds Flow
rate of polishing composition: 200 mL/min
[0043] As shown in Table 1, the results obtained for the polishing
compositions of Examples 1-21 were practically satisfactory with
regard to polishing rate and surface defects. In contrast, no
practically satisfactory results were obtained in Comparative
Examples 1-6 at least with regard to surface defects. In addition,
it turned out from the results of Examples 1-4 that good results
were obtained with regard to defoaming properties when the HLB
value of polyether modified silicone oil contained in the polishing
composition was less than 16, or even it was less than 12.
* * * * *