U.S. patent application number 15/366380 was filed with the patent office on 2017-05-11 for polishing liquid and method for polishing substrate using the polishing liquid.
The applicant listed for this patent is Hitachi Chemical Company, Ltd.. Invention is credited to Takaaki Matsumoto, Munehiro Oota, Takashi Shinoda, Toshio Takizawa, Takaaki Tanaka, Shigeru Yoshikawa, Takahiro Yoshikawa.
Application Number | 20170133237 15/366380 |
Document ID | / |
Family ID | 46314047 |
Filed Date | 2017-05-11 |
United States Patent
Application |
20170133237 |
Kind Code |
A1 |
Oota; Munehiro ; et
al. |
May 11, 2017 |
POLISHING LIQUID AND METHOD FOR POLISHING SUBSTRATE USING THE
POLISHING LIQUID
Abstract
Provided is a polishing liquid including cerium oxide particles,
an organic acid A, a polymer compound B having a carboxyl acid
group or a carboxylate group, and water, wherein the organic acid A
has at least one group selected from the group consisting of --COOM
group, -Ph-OM group, --SO.sub.3M group and --PO.sub.3M.sub.2 group,
pKa of the organic acid A is less than 9, a content of the organic
acid A is 0.001 to 1 mass % with respect to the total mass of the
polishing liquid, and a content of the polymer compound B is 0.01
to 0.50 mass % with respect to the total mass of the polishing
liquid, and pH is in the range of 4.0 to 7.0.
Inventors: |
Oota; Munehiro; (Ibaraki,
JP) ; Tanaka; Takaaki; (Ibaraki, JP) ;
Takizawa; Toshio; (Ibaraki, JP) ; Yoshikawa;
Shigeru; (Ibaraki, JP) ; Matsumoto; Takaaki;
(Ibaraki, JP) ; Yoshikawa; Takahiro; (Ibaraki,
JP) ; Shinoda; Takashi; (Ibaraki, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hitachi Chemical Company, Ltd. |
Tokyo |
|
JP |
|
|
Family ID: |
46314047 |
Appl. No.: |
15/366380 |
Filed: |
December 1, 2016 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13884883 |
May 10, 2013 |
9564337 |
|
|
PCT/JP2011/079873 |
Dec 22, 2011 |
|
|
|
15366380 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B24B 37/044 20130101;
H01L 21/30625 20130101; H01L 21/31055 20130101; C09K 3/1463
20130101; C09G 1/02 20130101; H01L 21/31053 20130101 |
International
Class: |
H01L 21/3105 20060101
H01L021/3105; B24B 37/04 20060101 B24B037/04; C09G 1/02 20060101
C09G001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 24, 2010 |
JP |
2010-287594 |
Claims
1. A polishing liquid for chemical mechanical polishing comprising:
cerium oxide particles, an organic acid A, a polymer compound B
having a carboxyl acid group or a carboxylate group, and water,
wherein the organic acid A is propionic acid, a content of the
organic acid A is 0.001 to 1 mass % with respect to the total mass
of the polishing liquid, a content of the polymer compound B is
0.01 to 0.50 mass % with respect to the total mass of the polishing
liquid, and a pH of the polishing liquid is in the range of 4.0 to
7.0.
2. The polishing liquid according to claim 1, wherein the polishing
liquid is stored as a two liquid-type polishing liquid consisting
of a first liquid comprising the cerium oxide particles and the
water, and a second liquid comprising the organic acid A, the
polymer compound B and the water, wherein the first liquid and a
second liquid are combined prior to use, thereby forming the
polishing liquid.
3. The polishing liquid according to claim 2, wherein the first
liquid further comprises a dispersant.
4. A substrate polishing method for polishing a polishing target
film formed on a surface of a substrate, the method comprising the
steps of: (a) providing a polishing target film formed on a surface
of a substrate; (b) providing the polishing liquid according to
claim 1; and (c) polishing the polishing target film with the
polishing liquid according to claim 1.
5. A substrate polishing method for polishing a polishing target
film formed on a surface of a substrate, the method comprising the
steps of: (a) providing a polishing target film formed on a surface
of a substrate; (b) providing the polishing liquid according to
claim 2; and (c) polishing the polishing target film with the
polishing liquid according to claim 2.
6. A substrate polishing method for polishing a polishing target
film formed on a surface of a substrate, the method comprising the
steps of: (a) providing a polishing target film formed on a surface
of a substrate; (b) providing the polishing liquid according to
claim 3; and (c) polishing the polishing target film with the
polishing liquid according to claim 3.
7. The polishing liquid according to claim 1, wherein the polymer
compound B is poly(meth)acrylic acid.
Description
TECHNICAL FIELD
[0001] The present invention relates to a polishing liquid and a
method for polishing a substrate using the polishing liquid. More
particularly, the present invention relates to a polishing liquid
for use in production of semiconductor devices, for example, a
smoothening process of a substrate surface, especially, a
smoothening process of an interlayer dielectric film and a BPSG
film (silicon dioxide film doped with boron and phosphorous), and a
process of forming a shallow trench isolation (STI), and also
relates to a method for polishing a substrate using the polishing
liquid.
BACKGROUND ART
[0002] In production of an ultra large scale integrated (ULSI)
semiconductor device, a processing technique for achieving high
density and miniaturization of a semiconductor device is currently
being studied and developed. One of the processing techniques, a
chemical mechanical polishing (CMP) technique becomes essential in
production of semiconductor devices for the smoothening of an
interlayer dielectric film, the formation of a shallow trench
isolation (STI), and the formation of plugs and embedded metal
wirings.
[0003] In a conventional production process of semiconductor
devices, an inorganic insulation film such as a silicon oxide film
is formed through plasma CVD (chemical vapor deposition),
low-pressure CVD, etc. A fumed silica-based polishing liquid is
commonly studied as a chemical mechanical polishing liquid for use
in smoothening of the inorganic insulation film. The fumed
silica-based polishing liquid is prepared by adjusting the pH of
slurry in which particles obtained through grain growth using a
method such as thermal decomposition of silicon tetrachloride are
mixed. However, the fumed silica-based polishing liquid still has a
technical problem that a polishing speed is low.
[0004] Also, in the generation of a design rule of 0.25 .mu.m or
later, STI has been used for isolation of devices in an integrated
circuit. For STI, CMP technique is used for removal of an excessive
silicon oxide film formed on a substrate. In this case, a stopper
film with a low polishing speed is formed under the silicon oxide
film so as to stop polishing at a given depth. A silicon nitride
film or the like is used as the stopper film. Not only to
effectively remove the excessive silicon oxide film but also to
sufficiently prevent the progress of polishing thereafter, a
polishing speed ratio between the silicon oxide film and the
stopper film is preferably high. However, a conventional colloidal
silica-based polishing liquid has a low polishing speed ratio of
about 3 between the silicon oxide film and the stopper film, and
thus does not have sufficient properties practically usable for
STI.
[0005] As a polishing liquid for the surface of a glass such as a
photomask and a lens, a cerium oxide polishing liquid containing
cerium oxide particles is in use. Since the cerium oxide particles
are lower in hardness than silica particles or alumina particles
and are less likely to cause a polishing surface to be scratched
during polishing, the cerium oxide particles are useful for
finishing mirror-surface polishing. Furthermore, the cerium oxide
polishing liquid has an advantage that the polishing speed is
faster than that of a silica polishing liquid such as a fumed
silica- or colloidal silica-based polishing liquid.
[0006] As the cerium oxide polishing liquid, Patent Literature 1
below discloses a chemical mechanical polishing liquid for
semiconductors using high-purity cerium oxide abrasive particles.
Also, Patent Literature 2 below discloses a technique for adding an
additive in order to control a polishing speed of a cerium oxide
polishing liquid and improve global smoothness.
PRIOR ART LITERATURES
Patent Literature
[0007] [Patent Literature 1] Japanese Patent Application Laid-open
No. H10-106994
[0008] [Patent Literature 2] Japanese Patent No. 3278532
SUMMARY OF INVENTION
Technical Problem
[0009] However, as a design rule for wiring or STI progressively
shrinks, it is further required to improve smoothness for the
cerium oxide polishing liquid (for example, to reduce a dishing
amount of an insulation film). Also, improvement of precision in
production of semiconductor devices is increasingly demanded, for
example, it is required that a difference in residual film
thickness between insulation films in regions with different trench
densities should be small or an excessively polished amount of a
stopper film should be small. Furthermore, the high likelihood of a
polishing process is also important in production of highly precise
semiconductor devices.
[0010] The present invention was made in consideration of the
above-described actual situations, and an object of the present
invention is to provide a polishing liquid and a method for
polishing a substrate using the polishing liquid, capable of
improving a polishing speed of a polishing target film and
improving smoothness after polishing, in a CMP technique of
polishing a polishing target film which is formed on the surface of
a substrate.
Solution to Problem
[0011] To solve the problems above, the present invention provides
a polishing liquid for chemical mechanical polishing (CMP)
including cerium oxide particles, an organic acid A, a polymer
compound B having a carboxyl acid group or a carboxylate group, and
water, wherein the organic acid A has at least one group selected
from the group consisting of --COOM group, -Ph-OM group
(phenolic-OM group), --SO.sub.3M group, and --PO.sub.3M.sub.2 group
(where, M is at least one selected from the group of H, NH.sub.4,
Na and K, and Ph represents a phenyl group which may have a
substituent), pKa of the organic acid A is less than 9, a content
of the organic acid A is 0.001 to 1 mass % with respect to the
total mass of the polishing liquid, and a content of the polymer
compound B is 0.01 to 0.50 mass % with respect to the total mass of
the polishing liquid, and pH ranges between 4.0 to 7.0.
[0012] The polishing liquid of the present invention can improve a
polishing speed of a polishing target film and also improve
smoothness after polishing in a CMP technique of polishing a
polishing target film (for example, an interlayer dielectric film,
a BPSG film, an STI film) formed on the surface of a substrate.
[0013] The polishing liquid of the present invention may be stored
as a two-liquid type polishing liquid including a first liquid and
a second liquid, where the first liquid contains cerium oxide
particles, and water, and the second liquid contains an organic
acid A, a polymer compound B, and water. This makes it possible to
more stably maintain dispersion stability of the cerium oxide
particles until just prior to using a polishing liquid, and
therefore the polishing speed and smoothness can be more
effectively improved.
[0014] Also, in the polishing liquid of the present invention, it
is desirable that the first liquid further includes a dispersant.
This enables the dispersion stability of cerium oxide particles to
be more excellently maintained.
[0015] The present invention also provides a polishing method of a
substrate, for polishing a polishing target film formed on the
surface of the substrate by using the polishing liquid of the
present invention. According to the polishing method using the
polishing liquid of the present invention, it is possible to
improve the polishing speed of the polishing target film and also
to improve smoothness after polishing.
Advantageous Effects of Invention
[0016] According to the present invention, it is possible to
provide a polishing liquid and a method for polishing a substrate
using the polishing liquid, capable of improving a polishing speed
of a polishing target film and also improving surface smoothness
after polishing, in a CMP technique of polishing the polishing
target film (for example, STI film) which is formed on the surface
of the substrate.
BRIEF DESCRIPTION OF DRAWINGS
[0017] FIG. 1 is a schematic sectional diagram illustrating an
evaluation substrate for polishing properties.
DESCRIPTION OF EMBODIMENTS
[0018] Hereinafter, embodiments of the present invention will be
described below in detail.
[0019] [Polishing Liquid]
[0020] A polishing liquid according to a current embodiment is a
polishing liquid for chemical mechanical polishing (CMP), which
contains cerium oxide particles, a dispersant, an organic acid A, a
polymer compound B, and water. Hereinafter, each component
contained in the polishing liquid according to the current
embodiment will be fully described.
[0021] (Cerium Oxide Particles)
[0022] As cerium oxide particles, well-known materials may be used
without particular limitation. In general, cerium oxide is obtained
by oxidation of a cerium compound such as carbonate, nitrate,
sulfate, and oxalate. The cerium oxide particles may be prepared
by, for example, calcination, oxidation with hydrogen peroxide, or
the like.
[0023] The cerium oxide particles for use in polishing of a silicon
oxide film formed by TEOS-CVD or other methods allows higher-speed
polishing, but causes more polishing scratches on a polishing
target film, when the crystallite diameter (diameter of
crystallite) of the cerium oxide particle becomes greater and the
crystal distortion is smaller, i.e., when the crystallinity thereof
is higher. From this point of view, the cerium oxide particle is
preferably composed of two or more crystallites and has crystal
grain boundaries, and more preferably, has the crystallite diameter
ranging from 1 to 300 nm.
[0024] The crystallite diameter may be measured through observation
using a scanning electron microscope (SEM). Specifically, a major
axis and a minor axis of the particle are measured from an image
obtained by the SEM, and the square root of the product of the
major axis and the minor axis is determined as a particle
diameter.
[0025] The content of alkali metals and halogens in the cerium
oxide particle is preferably 10 ppm or less because the particle
may be favorably used for polishing during production of
semiconductor devices.
[0026] The average particle diameter of the cerium oxide particles
is preferably in the range of 10 to 500 nm, more preferably in the
range of 20 to 400 nm, and even more preferably in the range of 50
to 300 nm. If the average particle diameter of the cerium oxide
particles is 10 nm or more, good polishing speed tends to be
achieved; and if the average particle diameter is 500 nm or less,
the polishing target film is less likely to be scratched.
[0027] Herein, the average particle diameter of the cerium oxide
particles means the D50 value (median diameter of volumetric
distribution, cumulative median value), as measured with a laser
diffraction particle size distribution analyzer (for example,
Master Sizer Microplus.TM. (refractive index: 1.93, light source:
He--Ne laser, and absorption: 0) manufactured by Malvern Instrument
Ltd.). A sample in which a polishing liquid is diluted to a
suitable concentration (for example, concentration at which
transmittance (H) becomes 60-70% as measured with He--Ne laser) is
used in measuring of the average particle diameter. Also, when the
cerium oxide polishing liquid is divided into a cerium oxide slurry
in which cerium oxide particles are dispersed in water, and an
additive solution in which an additive is dissolved in water, and
the cerium oxide slurry and the additive solution are separately
stored, the measurement may be carried out by diluting the cerium
oxide slurry to a suitable concentration.
[0028] In view of the tendency that a good polishing speed is
achieved, the content of the cerium oxide particles is preferably
0.1 mass % or more, and more preferably 0.5 mass % or more, based
on a total mass of the polishing liquid. Also, considering that the
aggregation of the particles is prevented and thus the polishing
target film is less likely to be scratched, the content of the
cerium particles is preferably 20 mass % or less, more preferably 5
mass % or less, and even more preferably 1.5 mass % or less.
[0029] (Organic Acid A)
[0030] The polishing liquid according to the current embodiment
includes, as an organic acid A, an organic acid and/or salts
thereof. Thus, it is possible to increase a polishing speed and
also improve smoothness of the polishing target film (for example,
silicon oxide film) after the polishing is completed. More
specifically, when an uneven polishing target surface is polished,
a polishing time may be shortened, and furthermore, a phenomenon in
which a portion of the surface is excessively polished to have a
caved-in shape like a dish, which is so-called dishing, can be
prevented. This effect can be more effectively achieved by combined
use of the organic acid and/or salts thereof and the cerium oxide
particles.
[0031] The organic acid and/or salts thereof has at least one group
selected from the group consisting of --COOM group, -Ph-OM group
(phenolic-OM group), --SO.sub.3M group, and --PO.sub.3M.sub.2 group
(where, M is at least one selected from the group of H, NH.sub.4,
Na and K, and Ph represents a phenyl group which may have a
substituent), and is preferably a water-soluble organic
compound.
[0032] For examples, the organic acid A may include: a carboxylic
acid such as formic acid, acetic acid, propionic acid, butyric
acid, valeric acid, cyclohexane carboxylic acid, phenylacetic acid,
benzoic acid, o-toluic acid, m-toluic acid, p-toluic acid,
o-methoxybenzoic acid, m-methoxybenzoic acid, p-mthoxybenzoic acid,
acrylic acid, methacrylic acid, crotonic acid, pentenoic acid,
hexenoic acid, heptenoic acid, octenoic acid, nonenoic acid,
decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid,
tetradecenoic acid, pentadecenoic acid, hexadecenoic acid,
heptadecenoic acid, isobutyric acid, isovaleric acid, cinnamic
acid, quinaldic acid, nicotinic acid, 1-naphthoic acid, 2-naphthoic
acid, picolinic acid, vinylacetic acid, phenylacetic acid,
phenoxyacetic acid, 2-furancarboxylic acid, mercaptoacetic acid,
levulinic acid, oxalic acid, malonic acid, succinic acid, glutaric
acid, adipic acid, pimelic acid, suberic acid, azelaic acid,
sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decandicarboxylic
acid, 1,11-undecanedicarboxylic acid, 1,12-dodecane dicarboxylic
acid, 1,13-tridecane dicarboxylic acid, 1,14-tetradecane
dicarboxylic acid, 1,15-pentadecane dicarboxylic acid,
1,16-hexadecane dicarboxylic acid, maleic acid, fumaric acid,
itaconic acid, citraconic acid, mesaconic acid, quinolinic acid,
quinic acid, naphthalic acid, phthalic acid, isophthalic acid,
terephthalic acid, glycollic acid, lactic acid, 3-hydroxypropionic
acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid,
4-hydroxybutyric acid, 3-hydroxyvaleric acid, 5-hydroxyvaleric
acid, quinic acid, kynurenic acid, salicylic acid, tartaric acid,
aconitinic acid, ascorbic acid, acetylsalicylic acid, acetylmalic
acid, acetylene dicarboxylic acid, acetoxy succinic acid,
acetylacetic acid, 3-oxoglutaric acid, atropic acid, atrolactic
acid, anthraquinone carboxylic acid, anthracene carboxylic acid,
isocaproic acid, isocamphoronic acid, isocrotonic acid,
2-ethyl-2-hydroxybutyric acid, ethylmalonic acid, ethoxy acetic
acid, oxaloacetic acid, oxydiacetic acid, 2-oxobutanoic acid,
camphoronic acid, citric acid, glyoxylic acid, glycidic acid,
glyceric acid, glucaric acid, gluconic acid, croconic acid,
cyclobutane carboxylic acid, cyclohexane dicarboxylic acid,
diphenyl acetic acid, di-O-benzoyl-tartaric acid, dimethyl succinic
acid, dimethoxyphthalic acid, tartronic acid, tannic acid,
thiophene carboxylic acid, tiglic acid, desoxalic acid,
tetrahydroxy succinic acid, tetramethyl succinic acid, tetronic
acid, dihydroacetic acid, terebic acid, tropic acid, vanillic acid,
paraconic acid, hydroxyisophthalic acid, hydroxycinnamic acid,
hydroxynaphthoic acid, o-hydroxyphenylacetic acid,
m-hydroxyphenylacetatic acid, p-hydroxyphenylacetatic acid,
3-hydroxy-3-phenylpropionic acid, pivalic acid,
pyridinedicarboxylic acid, pyridine tricarboxylic acid, pyruvic
acid, .alpha.-phenylcinnamic acid, phenyl glycidic acid, phenyl
succinic acid, phenylacetic acid, phenyl lactic acid, propiolic
acid, sorbic acid, 2,4-hexadiene dioic acid, 2-benzylidyne
propionic acid, 3-benzylidyne propionic acid, benzylidyne malonic
acid, benzilic acid, benzene tricarboxylic acid, 1,2-benzene
diacetic acid, benzoyloxyacetic acid, benzoyloxy propionic acid,
benzoylformic acid, benzoylacetic acid, O-benzoyl lactic acid,
3-benzoyl propionic acid, gallic acid, mesoxalic acid, 5-methyl
isophthalic acid, 2-methyl crotonic acid, .alpha.-methyl cinnamic
acid, methyl succinic acid, methyl malonic acid, 2-methylbutyric
acid, o-methoxycinnamic acid, p-methoxycinnamic acid,
mercaptosuccinic acid, mercaptoacetic acid, 0-lactoyllactic acid,
malic acid, leuconic acid, leucic acid, rhodizonic acid, rosolic
acid, .alpha.-ketoglutaric acid, L-ascrobic acid, iduronic acid,
galacturonic acid, glucuronic acid, pyroglutamic acid,
ethylenediaminetetraacetic acid, cyano-triacetic acid, aspartic
acid, glutamic acid, N'-hydroxyethyl-N, N, N'-triacetic acid, and
nitrilotriacetic acid;
[0033] a sulfonic acid such as methanesulfonic acid, ethanesulfonic
acid, propanesulfonic acid, butanesulfonic acid, pentanesulfonic
acid, hexanesulfonic acid, heptanesulfonic acid, octanesulfonic
acid, nonanesulfonic acid, decanesulfonic acid, undecane sulfonic
acid, dodecane sulfonic acid, tridecane sulfonic acid, tetradecane
sulfonic acid, pentadecane sulfonic acid, hexadecane sulfonic acid,
heptadecane sulfonic acid, octadecane sulfonic acid,
benzenesulfonic acid, naphthalenesulfonic acid, toluenesulfonic
acid, hydroxyethane sulfonic acid, hydroxyphenol sulfonic acid, and
anthracene sulfonic acid; and
[0034] a phosphonic acid such as decyl phosphonic acid and phenyl
phosphonic acid. Furthermore, the carboxylic acid, sulfonic acid
and phosphonic acid may be their derivatives obtained by
substituting one or at least two protons of main chains thereof
with an atom or atomic group such as F, Cl, Br, I, OH, CN and
NO.sub.2. They may be used in such a way that one species is used
singly or two or more species are used in combination with each
other.
[0035] The content of the organic acid A (organic acid and/or salts
thereof) is in the range of 0.001 to 1 mass % based on the total
mass of the polishing liquid. If the content of the organic acid
and/or salts thereof is 0.001 mass % or more, there is a tendency
that the smoothness of the polishing target film (for example,
silicon oxide film) can be improved after the completion of
polishing. From this point of view, the content of the organic acid
and/or salts thereof is preferably 0.005 mass % or more, and more
preferably 0.01 mass % or more. On the other hand, if the content
is 1 mass % or less, the polishing speed of the polishing target
film is likely to be sufficiently increased, and the aggregation of
the cerium oxide particles is likely to be prevented. From this
point of view, therefore, the content of the organic acid and/or
salts thereof is preferably 0.1 mass % or less, and more preferably
0.05 mass % or less.
[0036] The organic acid A has an acid dissociation constant pKa
(pKa.sub.1 of the first stage which is the lowest acid dissociation
constant if number of pKa is two or more) of less than 9 at a room
temperature (25.degree. C.); however, pKa of the organic acid A is
preferably less than 8, more preferably less than 7, even more
preferably than 6, and most preferably than 5. If pKa of the
organic acid A is less than 9, at least a portion of the organic
acid A in the polishing liquid is changed to organic acid ions to
release hydrogen ions, thereby maintaining pH in the desired
range.
[0037] (Polymer Compound B)
[0038] The polishing liquid according to the current embodiment
includes a polymer compound B having a carboxylic acid group or
carboxylate group. Here, the carboxylic acid group is a functional
group expressed as --COOH, and the carboxylate group is a
functional group expressed as --COOX (where X is a cation derived
from a base and may include, for example, ammonium ion, sodium ion,
or potassium ion). In particular, as the polymer compound B, the
polishing liquid preferably contains a water-soluble organic
polymer and/or salts thereof, which has a carboxylic acid or
carboxylate group. Thus, it is possible to improve the smoothness
of the polishing target film (for example, silicon oxide film)
after the polishing is completed. More specifically, when an uneven
polishing target surface is polished, a phenomenon in which a
portion of the surface is excessively polished to have a caved-in
shape like a dish, which is so-called dishing, may be prevented.
This effect can be more effectively achieved by combined use of the
water-soluble organic polymer having the carboxylic acid group or
carboxylate group and salts thereof, the organic acid and/or salts
thereof, and the cerium oxide particles.
[0039] Specific examples of the polymer compound B (water-soluble
organic polymer having a carboxylic acid group or carboxylate
group) may include:
[0040] polycarboxyliic acid such as polyaspartic acid, polyglutamic
acid, polylysine, polymalic acid, polyamic acid, polyamic acid
ammonium salt, polyamide acid sodium salt, and polyglyoxylic acid,
and salts thereof; and
[0041] a homopolymer of monomers having a carboxylic acid group
such as acrylic acid, methacrylic acid, maleic acid, and a
homopolymer in which a carboxylic acid moiety of the polymer is
ammonium salt.
[0042] Also, the polymer compound B may include a copolymer of
monomers having a carboxylate group and a derivative such as alkyl
ester of a carboxylic acid. Specific examples thereof may include
poly(meth)acrylic acid, or a polymer in which the carboxylic acid
moiety of poly(meth)acrylic acid is substituted with ammonium
carboxylate group (hereinafter, ammonium poly(meth)acrylate). Here,
the poly(meth)acrylic acid represents at least either one of
polyacrylic acid or polymethacrylic acid.
[0043] Among these, the polymer compound B is preferably a
homopolymer of monomers having a carboxylic acid such as acrylic
acid, methacrylic acid, maleic acid, or a homopolymer in which the
carboxylic acid moiety of the polymer is an ammonium salt; more
preferably a homopolymer of (meth)acrylic acid (poly(meth)acrylic
acid) and an ammonium salt thereof; and even more preferably
polyacrylic acid and an ammonium salt thereof.
[0044] In view of the tendency that the smoothness of the polishing
target film (for example, silicon oxide film) after the completion
of polishing can be improved, the content of the polymer compound B
is 0.01 mass % or more based on the total mass of the polishing
liquid; however, from the same point of view, the content of the
polymer compound B is preferably 0.02 mass % or more, and more
preferably 0.05 mass % or more. If the content is 0.50 mass % or
less, the polishing speed of the polishing target film is likely to
be sufficiently increased, and the aggregation of the cerium oxide
particles is likely to be prevented. Thus, from this point of view,
the content of the polymer compound B is 0.50 mass % or less,
preferably 0.40 mass % or less, more preferably 0.30 mass % or
less, and even more preferably 0.20 mass %.
[0045] The weight average molecular weight of the polymer compound
B, although not particularly limited, is preferably 100,000 or
less, and more preferably 10,000 or less, in view of the tendency
that the polishing speed of the polishing target film is
sufficiently achieved and the aggregation of the cerium oxide
particles is prevented with ease. Also, in view of the tendency
that the smoothness enhancement effect is achieved with ease, the
weight average molecular weight of the polymer compound B is
preferably 1,000 or more. Also, the weight average molecular weight
is a value measured according to gel permeation chromatography
(GPC), and calculated based on reference polyoxyethyelene.
[0046] (Water)
[0047] Water, although not particularly limited, is preferably
deionized water, ion exchange water, ultra pure water, or the like.
The content of water may be a remainder of the contents of the
respective components, and is not specifically limited as long as
the water is contained in the polishing liquid. Also, the polishing
liquid may contain a solvent other than water as necessary, for
example, a polar solvent such as ethanol and acetone.
[0048] (Dispersant)
[0049] The polishing liquid according to the current embodiment may
include a dispersant for allowing the cerium oxide particles to be
dispersed. The dispersant may include a water-soluble anionic
dispersant, water-soluble non-ionic dispersant, water-soluble
cationic dispersant, water-soluble amphoteric dispersant, and the
like, and is preferably a water-soluble anionic dispersant among
others. They may be used in such a way that one species is used
singly or two or more species are used in combination with each
other. Also, the compound (for example, ammonium polyacrylate)
illustrated as an example of the polymer compound B may be used as
the dispersant.
[0050] The water-soluble anionic dispersant is preferably a polymer
containing an acrylic acid as a copolymerization component and
salts thereof, and more preferably the salts of the polymer. The
polymer containing an acrylic acid as a copolymerization component
and the salts thereof may include, for example, a polyacrylic acid
and ammonium salts thereof, a copolymer of acrylic acid and
methacrylic acid and ammonium salts thereof, and a copolymer of
acrylate amide and acrylic acid and ammonium salts thereof.
[0051] Other water-soluble anionic dispersants may include, for
example, triethanolamine laurylsulfate, ammonium laurylsulfate,
triethanolamine polyoxyethylene alkylether sulfate, and special
polycarboxylate polymer dispersants.
[0052] Furthermore, the water-soluble non-ionic dispersant may
include, for example, polyethylene glycol monolaurate, polyethylene
glycol monostearate, polyethylene glycol distearate, polyethylene
glycol monooleate, polyoxyethylene alkyl amine, polyoxyethylene
hydrogenated castor oil, 2-hydroxyethyl methacrylate, and alkyl
alkanol amide.
[0053] The water-soluble cationic dispersant may include, for
example, polyvinyl pyrrolidone, coconut amine acetate, and
stearylamine acetate.
[0054] The water-soluble amphoteric dispersant may include, for
example, lauryl betaine, stearyl betaine, lauryldimethylamine oxide
and 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium
betaine.
[0055] The content of the dispersant is preferably in the range of
0.001 to 10 mass % based on the total mass of the polishing liquid,
for improving the dispersibility of the cerium oxide particles to
prevent sedimentation and minimizing polishing scratches on the
polishing target film.
[0056] The weight average molecular weight of the dispersant,
although not specifically limited, is preferably in the range of
100 to 150,000, and more preferably in the range of 1,000 to
20,000. If the molecular weight of the dispersant is 100 or more, a
good polishing speed is likely to be achieved when the polishing
target film such as a silicon oxide film or a silicon nitride film
is polished. If the molecular weight of the dispersant is 150,000
or lower, the storage stability of the polishing liquid is less
likely to be decreased. Also, the weight average molecular weight
is a value measured according to GPC, and calculated based on
reference polyoxyethyelene.
[0057] [Other Additives]
[0058] The polishing liquid according to the current embodiment may
use a water-soluble polymer as an additive in addition to the
organic acid and/or salts thereof, and the water-soluble organic
polymer having a carboxylic acid group or carboxylate group and/or
salts thereof. Such a water-soluble polymer may include, for
example, polysaccharides such as alginic acid, pectinic acid,
carboxymethyl cellulose, agar, curdlan and pullulan; and vinyl
polymers such as polyvinyl alcohol, polyvinyl pyrrolidone and
polyacrolein.
[0059] The weight average molecular weight of the water-soluble
polymer is preferably 500 or more. In addition, the weight average
molecular weight is a value measured according to GPC, and
calculated based on reference polyoxyethyelene. Also, the content
of the water-soluble polymer is preferably in the range of 0.01 to
5 mass % based on the total mass of the polishing liquid.
[0060] [Methods of Preparing and Storing Polishing Liquid]
[0061] The polishing liquid according to the current embodiment is
obtained by mixing cerium oxide particles, water and a dispersant,
then dispersing the cerium oxide particles in the water, and adding
an organic acid A and a polymer compound B to the mixture. The
polishing liquid according to the current embodiment may be stored
as one liquid-type polishing liquid including the cerium oxide
particles, dispersant, organic acid A, polymer compound B, water,
and optionally a water-soluble polymer. Also, the polishing liquid
may be stored as two liquid-type polishing liquid which is composed
of cerium oxide slurry (first liquid) containing the cerium oxide
particles, dispersant and water, and an additive solution (second
liquid) containing the organic acid A, polymer compound B, water
and optionally water-soluble polymer.
[0062] Also, in the case of the two-liquid type polishing liquid,
the additives other than the organic acid A and the polymer
compound B may be included in either of the cerium oxide slurry or
the additive solution; however, it is desirable that the additives
are included in the additive solution because there is no effect on
the dispersion stability of the cerium oxide particles.
[0063] In the case that the polishing liquid is stored as the two
liquid-type polishing liquid by dividing the polishing liquid into
the cerium oxide slurry and the additive solution, it is possible
to adjust the smoothness characteristic and the polishing speed by
optionally changing a mixing ratio of these two liquids. When
polishing is performed using the two liquid-type polishing liquid,
the cerium oxide slurry and the additive solution may be fed to a
polishing pad as they are supplied separately through different
supply pipes and then mixed immediately before a supply pipe outlet
where the supply pipes are connected, or the cerium oxide slurry
and the additive solution may be mixed with each other immediately
before polishing.
[0064] The polishing liquid and slurry according to the current
embodiment may be stored as a stock solution for polishing liquid
or a stock solution for slurry, which will be used after dilution
to, for example, twice or more with a liquid media such as water,
for minimizing costs caused by preservation, transportation, and
storage. The respective stock solutions may be diluted with a
liquid media immediately before polishing, and may also be diluted
on a polishing pad after the stock solution and the liquid media
are supplied onto the polishing pad.
[0065] A dilution rate of the stock solution is preferably 2 or
more, and more preferably 3 or more because reduction in costs
caused by preservation, transportation and storage becomes larger
as the dilution rate becomes higher. Although the upper limit of
the dilution rate is not specifically limited, higher dilution rate
results in a greater amount (higher concentration) of a component
included in the stock solution, thus resulting in the deterioration
of stability during storage. Therefore, the dilution rate is
preferably 10 or less, more preferably 7 or less, and even more
preferably 5 or less. The liquid components may be divided into
three or more liquids, and this case is also the same as above.
[0066] The pH of the polishing liquid according to the current
embodiment is adjusted to a desired value, and thereafter the
polishing liquid is provided for polishing. A pH adjuster, although
not specifically limited, may include, for example, an acid such as
nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid,
boric acid and acetic acid, and a base such as sodium hydroxide,
ammonia water, potassium hydroxide and calcium hydroxide. When the
polishing liquid is used in polishing of semiconductors, ammonia
water or an acidic component is suitably used. As the pH adjuster,
the ammonium salt of the water-soluble polymer which is partially
neutralized with ammonia in advance may be used.
[0067] The pH of the polishing liquid at room temperature
(25.degree. C.) is in the range of 4.0 to 7.0. Since the pH is 4.0
or higher, the storage stability of the polishing liquid tends to
be improved and the number of scratches of the polishing target
film tends to be decreased. From this observation, the pH is
preferably 4.5 or higher, and more preferably 4.8 or higher. If the
pH is 7.0 or less, the smoothness-enhancing effect can be
sufficiently produced. From the same point of view, the pH is
preferably 6.5 or less, more preferably 6.0 or less, and even more
preferably 5.5 or less. The pH of the polishing liquid may be
measured with a pH meter (for example, Model PH81 (trademark)
manufactured by Yokogawa Electronic Corp.). For example, after two
points calibration is performed using a standard buffer solution
(phthalate pH buffer solution, pH: 4.21 (25.degree. C.), and
neutral phosphate pH buffer solution, pH: 6.86 (25.degree. C.)), an
electrode was put into the polishing liquid, and the pH stabilized
after 2 minutes or more at 25.degree. C. was then measured.
[0068] Next, use of the polishing liquid according to the current
embodiment for polishing a polishing target film formed on the
surface of a substrate will be described below.
[0069] [Polishing Method]
[0070] In a polishing method of a substrate according to the
current embodiment, the polishing target film formed on the surface
of the substrate is polished using the polishing liquid. More
specifically, for example, while the polishing liquid is being
supplied between the polishing target film and the polishing pad in
a state where the polishing target film formed on the surface of
the substrate is pressed against a polishing pad of a polishing
table, the polishing target film is polished by moving the
substrate and the polishing surface plate relatively to each
other.
[0071] The substrate may include a substrate for use in production
of semiconductor devices, for example, a substrate having an
inorganic insulation film formed on a semiconductor substrate, such
as a semiconductor substrate having circuit elements and wiring
patterns formed thereon, and a semiconductor substrate having
circuit elements formed thereon.
[0072] The polishing target film may include, for example, an
inorganic insulation film such as a silicon oxide film, a silicon
nitride film, and a composite film of a silicon oxide film. The
inorganic insulation film formed on such a substrate is polished
with the polishing liquid according to the current embodiment to
thus remove surface irregularity of the inorganic insulation film,
and resultantly the substrate is smoothened over the entire
surface. Also, the polishing liquid according to the current
embodiment may be used for shallow trench isolation.
[0073] Hereinafter, the polishing method of the substrate will be
more fully described by taking, as an example, the semiconductor
substrate with the inorganic insulation film formed thereon.
[0074] As a polishing apparatus, a typical polishing apparatus
which is equipped with a holder for holding a substrate such as a
semiconductor substrate having a polishing target film and a motor
of which number of revolutions is adjustable, and has a polishing
table to which a polishing pad (abrasive cloth) is attachable may
be used. For example, a polisher (Model No. EPO-111) manufactured
by Ebara Corporation, and MIRRA and Reflexion polishers
manufactured by AMAT may be used as the polishing apparatus.
[0075] As a polishing pad, a typical nonwoven fabric, expanded
polyurethane, porous fluororesin, and the like, but not
specifically limited thereto, may be used. Also, it is desirable
that the polishing pad is processed to have a groove for holding
the polishing liquid therein.
[0076] Although polishing conditions are not particularly limited,
it is desirable that a rotational speed of the polishing table is
preferably low at 200 rpm or less so as to prevent the
semiconductor substrate from being separated, and a pressure
(processing load) applied to the semiconductor substrate preferably
does not exceed 100 kPa to prevent scratching after polishing.
During polishing, the polishing liquid is continuously supplied to
the polishing pad using a pump. The supply amount of the polishing
liquid is not limited, but, the surface of the polishing pad is
preferably covered with the polishing liquid all the time.
[0077] Preferably, the semiconductor substrate after polishing is
washed thoroughly with running water, and then dried by removing
the water droplets remaining on the semiconductor substrate using a
spin dryer or the like.
[0078] In this way, surface irregularity is removed by polishing
the inorganic insulation film of the polishing target film, and it
is thus possible to obtain a smoothened surface over the entire
surface of the semiconductor substrate. After the smoothened
shallow trench is formed, aluminum wirings are formed on the
inorganic insulation film, and an inorganic insulation film is
formed again between and on the wirings. Thereafter, the inorganic
insulation film is polished using the polishing liquid to thereby
obtain a smooth surface. By repeating this process several times, a
semiconductor substrate having desired number of layers can be
produced.
[0079] The inorganic insulation film polished by use of the
polishing liquid according to the current embodiment may include,
for example, a silicon oxide film and a silicon nitride film. The
silicon oxide film may be doped with an element such as phosphorous
and boron. The inorganic insulation film may be formed with
low-pressure CVD, plasma CVD, or the like.
[0080] The formation of the silicon oxide film by low-pressure CVD
is performed by using monosilane (SiH.sub.4) as a Si source and
oxygen (O.sub.2) as an oxygen source. The SiH.sub.4--O.sub.2-type
oxidation reaction is carried out at a low temperature of
400.degree. C. or less thereby obtaining the silicon oxide film. In
some cases, the silicon oxide film obtained by CVD is subjected to
heat treatment at 1,000.degree. C. or less. A
SiH.sub.4--O.sub.2--PH.sub.3-type reaction gas is preferably used
when the silicon oxide film is doped with phosphorous (P) for
achieving surface smoothness by high-temperature reflow.
[0081] The plasma CVD process has an advantage that chemical
reaction, which requires high temperature under normal thermal
equilibrium, is carried out at a low temperature. A method of
generating plasma may include two methods, that is, a capacitively
coupled method and an inductively coupled method. The reaction gas
may include SiH.sub.4--N.sub.2O-type gas using SiH.sub.4 as the Si
source and N.sub.2O as the oxygen source, and a TEOS-O-type gas
(TEOS-plasma CVD method) using tetraethoxysilane (TEOS) as the Si
source. The substrate temperature is preferably in the range of 250
to 400.degree. C., and the reaction pressure is preferably in the
range of 67 to 400 Pa.
[0082] The formation of the silicon nitride film by low-pressure
CVD is performed by using dichlorosilane (SiH.sub.2Cl.sub.2) as the
Si source and ammonia (NH.sub.3) as the nitrogen source. The
SiH.sub.2Cl.sub.2--NH.sub.3-type oxidation reaction is carried out
at a high temperature of 900.degree. C. thereby obtaining the
silicon nitride film. The reaction gas used to form the silicon
nitride film by the plasma CVD method may include a
SiH.sub.4--NH.sub.3-type gas containing SiH.sub.4 as the Si source
and NH.sub.3 as the nitrogen source. The substrate temperature is
preferably in the range of 300 to 400.degree. C.
[0083] The polishing liquid and the polishing method of the
substrate according to the current embodiment can be applied not
only to the inorganic insulation film formed on the semiconductor
substrate but also in a production process for various types of
semiconductor devices. The polishing liquid and the polishing
method of the substrate according to the current embodiment can be
applied to a silicon oxide film formed on a wiring board having
predetermined wirings; an inorganic insulation film such as glass
and silicon nitride; a film mainly containing polysilicon, Al, Cu,
Ti, TiN, W, Ta, TaN, or the like; an optical glass such as
photomask, lens, and prism; an inorganic conductive film such as
ITO; an optical integrated circuit, photoswitching element, optical
waveguide made of glass and a crystalline material; an end face of
an optical fiber; optical single crystals such as scintillator;
solid-state laser single crystals; blue laser LED sapphire
substrates; semiconductor single crystals such as SiC, GaP, and
GaAs; a glass plate for magnetic disk; and a magnetic head.
EXAMPLES
[0084] Hereinafter, the present invention is described with
reference to examples, however, the present invention is not
limited to the examples below.
[0085] (Preparation of Cerium Oxide Particles)
[0086] 40 kg of commercially available cerium carbonate hydrate was
put into an alumina container and calcined at 830.degree. C. for 2
hours in air to obtain 20 kg of yellow white powders. Phase
identification of these powders by X-ray diffractometry showed that
the product was cerium oxide. 20 kg of the cerium oxide powders
obtained were dry-pulverized by use of a jet mill to obtain powdery
(particulate) cerium oxide. Observation of the obtained powdery
cerium oxide using a scanning electron miscrope (SEM) showed that
crystallite-sized particles and particles consisting of two or more
crystallites and having a crystallite grain boundary were included
in cerium oxide. 50 crystallites were randomly selected from the
acquired SEM image, and then a particle diameter was calculated
from the square root of the product of the major axis and minor
axis of the particle, resulting in the crystallite diameters of all
the crystallites being within the range of 1-300 nm.
Example 1-1
[0087] 200.0 g of cerium oxide particles thus prepared and 795.0 g
of deionized water were mixed, then 5 g of an aqueous ammonium
polyacrylate solution (weight average molecular weight: 8,000, 40
mass %) as a dispersant was added, and the resulting mixture was
dispersed under ultrasonication while being stirred thereby
obtaining a cerium oxide dispersion liquid. The dispersion under
ultrasonication was performed at the ultrasonic wave frequency of
400 kHz for a dispersion period of 20 minutes.
[0088] Thereafter, 1 kg of the cerium oxide dispersion liquid was
put and left in a 1-liter container (height: 170 mm), and then
sedimentation classification was performed. After classification
for 15 hours, the supernatant liquid at a depth of 13 cm or less
from the surface of the water was drawn by a pump. The supernatant
cerium oxide dispersion liquid obtained was diluted with deionized
water to render the content of the cerium oxide particles be 5 mass
%, thereby obtaining a cerium oxide slurry.
[0089] To measure the average particle diameter (D50) of the cerium
oxide particle in the cerium oxide slurry, the slurry was diluted
to have the transmittance (H) of 60-70%, as measured with He--Ne
laser, thereby obtaining a sample to be measured. D50 of the sample
to be measured was 150 nm, as measured by using a laser-diffraction
particle size distribution analyzer, Master Sizer Microplus (trade
name, manufactured by Malvern) at a refractive index of 1.93 and
absorption of 0.
[0090] As the organic acid A, 0.1 g of p-toluenesulfonic acid
monohydrate (pKa(25.degree. C.)=-2.8) and 800 g of deionized water
were mixed, and then, as the polymer compound B, 2.5 g of aqueous
polyacrylic acid solution (weight average molecular weight: 4,000,
40 mass %) was added thereto. Thereafter, ammonia water (25 mass %)
was added to adjust pH to 4.5 (25.degree. C.). The deionized water
was further added, thereby obtaining a total amount of 850 g of the
additive solution of the organic acid.
[0091] Then, 134 g of the cerium oxide slurry was added, the
resulting mixture was adjusted to pH 5.0 (25.degree. C.) with
ammonia water (25 mass %), and deionized water was further added to
result in the total amount being 1,000 g, thereby producing a
cerium oxide polishing liquid (content of cerium oxide particles:
0.67 mass %).
[0092] Also, the average particle diameter D50 of the particles in
the polishing liquid, as measured by a laser-diffraction particle
size distribution analyzer after production of the sample to be
measured as above, was 150 nm.
[0093] (Polishing of Insulation Film)
[0094] A trade mark "Pattern Wafer 764" (diameter: 300 mm)
manufactured by SEMATECH was used as a polishing test wafer. The
polishing test wafer and the evaluation method of polishing
properties using the same will be described with reference to FIG.
1.
[0095] FIG. 1(a) is a schematic enlarged sectional view
illustrating a portion of a polishing test wafer. A plurality of
grooves are formed in the surface of wafer 1, and a silicon nitride
film 2 with a thickness of 150 nm (1,500 .ANG.) is formed on the
surface of a convex portion of the wafer 1. The depth of the groove
(step height from the surface of the convex portion to a bottom of
a concave portion) is 500 nm (5,000 .ANG.). Hereinafter, the convex
portion is referred to as an active portion, and the concave
portion is referred to as a trench portion. Also, although not
specifically depicted in FIG. 1, three regions which have sectional
widths of the trench portion/active portion being 100 .mu.m/100
.mu.m, 20 .mu.m/80 .mu.m and 80 .mu.m/20 .mu.m are formed in the
wafer 1.
[0096] FIG. 1(b) is a schematic enlarged sectional view
illustrating a portion of the polishing test wafer. Over the
polishing test wafer, a silicon oxide film 3 is formed on the
active portion and the trench portion through plasma-TEOS such that
the silicon oxide film 3 has a thickness of 600 nm (6,000 .ANG.)
from the surface of the active portion. In the polishing test,
smoothening is performed by polishing the silicon oxide film 3 of
the polishing test wafer.
[0097] FIG. 1(c) is a schematic enlarged sectional view
illustrating a portion of the polishing test wafer after the
silicon oxide film 3 is polished. Polishing is terminated at the
surface of the silicon nitride film 2 in the active portion, the
time required for the polishing is defined as a polishing period,
and a value obtained by subtracting a thickness 5 of the silicon
oxide film 3 in the trench portion from a depth 4 of the trench
portion is defined as a dishing amount 6. A shorter polishing
period is more favorable, and a smaller dishing amount 6 is also
more favorable.
[0098] A polishing apparatus (Reflexion manufactured by AMAT) was
used in polishing of the polishing test wafer. The polishing test
wafer was set on a holder to which an absorption pad for mounting a
substrate was attached. The polishing pad made of a porous urethane
resin (groove shape=perforate type: manufactured by Rohm and Haas,
Model No. IC1010) was attached to the polishing table with a
diameter of 600 mm of the polishing apparatus. The holder was
further placed on the polishing table with its insulation film
(silicon oxide film) face of the polishing target film facing
downward, and a processing load was set to 210 gf/cm.sup.2 (20.6
kPa).
[0099] The polishing test wafer was polished while the polishing
table and the polishing test wafer were moved at a speed of 130 rpm
and the cerium oxide polishing liquid was dropped onto the
polishing pad at a rate of 250 milliliter/minute. A polishing time
when the silicon nitride film of the active portion in the 100
.mu.m/100 .mu.m region is exposed was defined as a polishing
termination time. The evaluation of the smoothness was performed on
the wafer which is over-polished by 20% from the polishing
termination time (for example, if the polishing termination time is
100 seconds, the polishing is further performed for 20 seconds
thereafter). Over-polishing is performed to facilitate the
differences arising between the values of items to be evaluated and
therefore the ease of the evaluation, and also to verify the
advantage that the figures are good (or properties are good) even
when the over-polishing is performed, which lead to the process
likelihood in terms of a polishing process. The polishing test
wafer after polishing was washed thoroughly with pure water, and
then dried.
[0100] The following three items were evaluated as evaluation items
for smoothness.
Item 1: dishing amount of the trench portion in the 100 .mu.m/100
.mu.m region: measured by use of a stylus type step profiler (Model
No. P16, manufactured by KLA-Tencor). Item 2: SiN loss of the
active portion in the 100 .mu.m/100 .mu.m region: the thickness of
the silicon nitride (SiN) film removed by polishing was measured
using an interference type film thickness measuring device,
NanoSpec/AFT5100 (trade mark) manufactured by NanoMatrix Inc. Item
3: SiO.sub.2 remaining film thickness difference (SiO.sub.2 density
difference) of the trench portions between in the 20 .mu.m/80 .mu.m
and 80 .mu.m/20 .mu.m regions: the remaining thickness of the
silicon oxide film (SiO.sub.2 film) in each region was measured
using an interference type film thickness measuring device,
NanoSpec/AFT5100 (trade mark) manufactured by NanoMatrix Inc.
Examples 1-2 to 6-9 and Comparative Examples 1-1 to 6-9
[0101] Preparation of a cerium oxide polishing liquid and polishing
of an insulation film were performed in the same manner as Example
1-1 except for the pH of the polishing liquid, type and amount of
the organic acid A, or amount of the polymer compound B, which are
listed in Tables 1 to 19. Results are shown in the same Tables.
From Tables 1 to 19, it becomes evident that the polishing speed
and smoothness are enhanced and the dishing amount is reduced using
the polishing liquid according to the present invention.
TABLE-US-00001 TABLE 1 Polishing result SiO.sub.2 remaining Organic
acid A Polymer compound B film Mixing Mixing Polishing thickness
SiN amount amount period Dishing difference loss No. pH Name (mass
%) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.] (Comparative 3.5
p-toluenesulfonic 0.01 Polyacrylic 0.10 Evaluation stopped due to
aggregation Example 1-1) acid monohydrate acid of cerium oxide
particles (Mw = 4000) (Example 1-2) 4.5 p-toluenesulfonic 0.01
Polyacrylic 0.10 160 250 330 44 acid monohydrate acid (Mw = 4000)
(Example 1-1) 5.0 p-toluenesulfonic 0.01 Polyacrylic 0.10 145 300
350 50 acid monohydrate acid (Mw = 4000) (Example 1-3) 6.0
p-toluenesulfonic 0.01 Polyacrylic 0.10 150 320 400 56 acid
monohydrate acid (Mw = 4000) (Comparative 8.0 p-toluenesulfonic
0.01 Polyacrylic 0.10 140 850 800 55 Example 1-2) acid monohydrate
acid (Mw = 4000) (Comparative 9.0 p-toluenesulfonic 0.01
Polyacrylic 0.10 135 950 900 56 Example 1-3) acid monohydrate acid
(Mw = 4000) (Comparative 5.0 None -- Polyacrylic 0.10 135 700 750
120 Example 1-4) acid (Mw = 4000)
TABLE-US-00002 TABLE 2 Polishing result SiO.sub.2 remaining Organic
acid A Polymer compound B film Mixing Mixing Polishing thickness
SiN amount amount period Dishing difference loss No. pH Name (mass
%) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.] (Comparative 5.0 None
-- Polyacrylic 0.10 135 700 750 120 Example 1-4) acid (Mw = 4000)
(Comparative 5.0 p-toluenesulfonic 0.0001 Polyacrylic 0.10 140 600
650 100 Example 1-5) acid monohydrate acid (Mw = 4000) (Example
1-4) 5.0 p-toluenesulfonic 0.001 Polyacrylic 0.10 145 380 420 56
acid monohydrate acid (Mw = 4000) (Example 1-1) 5.0
p-toluenesulfonic 0.01 Polyacrylic 0.10 145 300 350 50 acid
monohydrate acid (Mw = 4000) (Example 1-5) 5.0 p-toluenesulfonic
0.1 Polyacrylic 0.10 160 250 300 46 acid monohydrate acid (Mw =
4000) (Example 1-6) 5.0 p-toluenesulfonic 1 Polyacrylic 0.10 175
260 280 42 acid monohydrate acid (Mw = 4000) (Comparative 5.0
p-toluenesulfonic 10 Polyacrylic 0.10 Evaluation stopped due to
Example 1-6) acid monohydrate acid aggregation of cerium oxide
particles (Mw = 4000)
TABLE-US-00003 TABLE 3 Polishing result SiO.sub.2 remaining Organic
acid A Polymer compound B film Mixing Mixing Polishing thickness
SiN amount amount period Dishing difference loss No. pH Name (mass
%) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.] (Comparative 5.0
p-toluenesulfonic 0.01 None -- 130 600 700 200 Example 1-7) acid
monohydrate (Comparative 5.0 p-toluenesulfonic 0.01 Polyacrylic
0.001 135 550 650 160 Example 1-8) acid monohydrate acid (Mw =
4000) (Example 1-7) 5.0 p-toluenesulfonic 0.01 Polyacrylic 0.01 140
340 400 60 acid monohydrate acid (Mw = 4000) (Example 1-1) 5.0
p-toluenesulfonic 0.01 Polyacrylic 0.10 145 300 350 50 acid
monohydrate acid (Mw = 4000) (Example 1-8) 5.0 p-toluenesulfonic
0.01 Polyacrylic 0.20 155 260 320 44 acid monohydrate acid (Mw =
4000) (Example 1-9) 5.0 p-toluenesulfonic 0.01 Polyacrylic 0.40 164
240 320 42 acid monohydrate acid (Mw = 4000) (Comparative 5.0
p-toluenesulfonic 0.01 Polyacrylic 1.00 Evaluation stopped due to
aggregation Example 1-9) acid monohydrate acid of cerium oxide
particles (Mw = 4000)
TABLE-US-00004 TABLE 4 Polishing result SiO.sub.2 remaining Organic
acid A Polymer compound B film Mixing Mixing Polishing thickness
SiN amount amount period Dishing difference loss No. pH Name (mass
%) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.] (Example 1-1) 5.0
p-toluenesulfonic 0.01 Polyacrylic 0.10 145 300 350 50 acid
monohydrate acid (pKa = -2.8) (Mw = 4000) (Example 5.0 Maleic acid
0.01 Polyacrylic 0.10 140 320 340 50 1-10) (pKa = 1.8) acid (Mw =
4000) (Example 5.0 Malic acid 0.01 Polyacrylic 0.10 150 330 360 60
1-11) (pKa = 3.4) acid (Mw = 4000) (Example 5.0 Succinic acid 0.01
Polyacrylic 0.10 155 330 370 55 1-12) (pKa = 4.2) acid (Mw = 4000)
(Example 5.0 Acetic acid 0.01 Polyacrylic 0.10 140 290 330 45 1-13)
(pKa = 4.8) acid (Mw = 4000) (Example 5.0 Propionic acid 0.01
Polyacrylic 0.10 150 310 360 60 1-14) (pKa = 4.9) acid (Mw = 4000)
(Comparative 7.0 Catechol 0.01 Polyacrylic 0.10 150 750 800 110
Example 1-10) (pKa = 9.2) acid (Mw = 4000) (Comparative 7.0 Phenol
0.01 Polyacrylic 0.10 150 700 750 105 Example 1-11) (pKa = 10.0)
acid (Mw = 4000)
TABLE-US-00005 TABLE 5 Polishing result SiO.sub.2 remaining Organic
acid A Polymer compound B film Mixing Mixing Polishing thickness
SiN amount amount period Dishing difference loss No. pH Name (mass
%) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.] (Comparative 3.5 Malic
acid 0.01 Polyacrylic 0.10 Evaluation stopped due to aggregation of
cerium Example 2-1) acid oxide particles (Mw = 4000) (Example 2-2)
4.5 Malic acid 0.01 Polyacrylic 0.10 170 270 320 48 acid (Mw =
4000) (Example 2-1) 5.0 Malic acid 0.01 Polyacrylic 0.10 150 330
360 60 acid (Mw = 4000) (Example 2-3) 6.0 Malic acid 0.01
Polyacrylic 0.10 155 310 390 54 acid (Mw = 4000) (Comparative 8.0
Malic acid 0.01 Polyacrylic 0.10 150 840 790 54 Example 2-2) acid
(Mw = 4000) (Comparative 9.0 Malic acid 0.01 Polyacrylic 0.10 145
930 920 55 Example 2-3) acid (Mw = 4000) (Comparative 5.0 None --
Polyacrylic 0.10 135 700 750 120 Example 2-4) acid (Mw = 4000)
TABLE-US-00006 TABLE 6 Polishing result SiO.sub.2 remaining Organic
acid A Polymer compound B film Mixing Mixing Polishing thickness
SiN amount amount period Dishing difference loss No. pH Name (mass
%) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.] (Comparative 5.0 None
-- Polyacrylic 0.10 135 700 750 120 Example 2-4) acid (Mw = 4000)
(Comparative 5.0 Malic acid 0.0001 Polyacrylic 0.10 145 630 650 110
Example 2-5) acid (Mw = 4000) (Example 2-4) 5.0 Malic acid 0.001
Polyacrylic 0.10 148 380 420 50 acid (Mw = 4000) (Example 2-1) 5.0
Malic acid 0.01 Polyacrylic 0.10 150 330 360 60 acid (Mw = 4000)
(Example 2-5) 5.0 Malic acid 0.1 Polyacrylic 0.10 162 260 320 48
acid (Mw = 4000) (Example 2-6) 5.0 Malic acid 1 Polyacrylic 0.10
170 240 290 45 acid (Mw = 4000) (Comparative 5.0 Malic acid 10
Polyacrylic 0.10 Evaluation stopped due to aggregation of cerium
Example 2-6) acid oxide particles (Mw = 4000)
TABLE-US-00007 TABLE 7 Polishing result SiO.sub.2 remaining Organic
acid A Polymer compound B film Mixing Mixing Polishing thickness
SiN amount amount period Dishing difference loss No. pH Name (mass
%) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.] (Comparative 5.0 Malic
acid 0.01 None -- 125 600 720 230 Example 2-7) (Comparative 5.0
Malic acid 0.01 Polyacrylic 0.001 140 550 660 180 Example 2-8) acid
(Mw = 4000) (Example 2-7) 5.0 Malic acid 0.01 Polyacrylic 0.01 145
340 390 60 acid (Mw = 4000) (Example 2-1) 5.0 Malic acid 0.01
Polyacrylic 0.10 150 330 360 60 acid (Mw = 4000) (Example 2-8) 5.0
Malic acid 0.01 Polyacrylic 0.20 160 250 320 48 acid (Mw = 4000)
(Example 2-9) 5.0 Malic acid 0.01 Polyacrylic 0.40 168 260 320 50
acid (Mw = 4000) (Comparative 5.0 Malic acid 0.01 Polyacrylic 1.00
Evaluation stopped due to aggregation of cerium Example 2-9) acid
oxide particles (Mw = 4000)
TABLE-US-00008 TABLE 8 Polishing result SiO.sub.2 remaining Organic
acid A Polymer compound B film Mixing Mixing Polishing thickness
SiN amount amount period Dishing difference loss No. pH Name (mass
%) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.] (Comparative 3.5
Acetic acid 0.01 Polyacrylic 0.10 Evaluation stopped due to
aggregation of cerium Example 3-1) acid oxide particles (Mw = 4000)
(Example 3-2) 4.5 Acetic acid 0.01 Polyacrylic 0.10 160 270 330 45
acid (Mw = 4000) (Example 3-1) 5.0 Acetic acid 0.01 Polyacrylic
0.10 140 290 330 45 acid (Mw = 4000) (Example 3-3) 6.0 Acetic acid
0.01 Polyacrylic 0.10 140 340 390 55 acid (Mw = 4000) (Comparative
8.0 Acetic acid 0.01 Polyacrylic 0.10 135 840 790 55 Example 3-2)
acid (Mw = 4000) (Comparative 9.0 Acetic acid 0.01 Polyacrylic 0.10
134 940 900 52 Example 3-3) acid (Mw = 4000) (Comparative 5.0 None
-- Polyacrylic 0.10 135 700 750 120 Example 3-4) acid (Mw =
4000)
TABLE-US-00009 TABLE 9 Polishing result SiO.sub.2 remaining Organic
acid A Polymer compound B film Mixing Mixing Polishing thickness
SiN amount amount period Dishing difference loss No. pH Name (mass
%) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.] (Comparative 5.0 None
-- Polyacrylic 0.10 135 700 750 120 Example 3-4) acid (Mw = 4000)
(Comparative 5.0 Acetic acid 0.0001 Polyacrylic 0.10 142 620 670
100 Example 3-5) acid (Mw = 4000) (Example 3-4) 5.0 Acetic acid
0.001 Polyacrylic 0.10 145 360 410 56 acid (Mw = 4000) (Example
3-1) 5.0 Acetic acid 0.01 Polyacrylic 0.10 140 290 330 45 acid (Mw
= 4000) (Example 3-5) 5.0 Acetic acid 0.1 Polyacrylic 0.10 165 260
310 46 acid (Mw = 4000) (Example 3-6) 5.0 Acetic acid 1 Polyacrylic
0.10 176 270 290 42 acid (Mw = 4000) (Comparative 5.0 Acetic acid
10 Polyacrylic 0.10 Evaluation stopped due to aggregation of cerium
Example 3-6) acid oxide particles (Mw = 4000)
TABLE-US-00010 TABLE 10 Polishing result SiO.sub.2 remaining
Organic acid A Polymer compound B film Mixing Mixing Polishing
thickness SiN amount amount period Dishing difference loss No. pH
Name (mass %) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.]
(Comparative 5.0 Acetic acid 0.01 None -- 132 620 710 220 Example
3-7) (Comparative 5.0 Acetic acid 0.01 Polyacrylic 0.001 136 560
660 150 Example 3-8) acid (Mw = 4000) (Example 3-7) 5.0 Acetic acid
0.01 Polyacrylic 0.01 140 350 420 55 acid (Mw = 4000) (Example 3-1)
5.0 Acetic acid 0.01 Polyacrylic 0.10 140 290 330 45 acid (Mw =
4000) (Example 3-8) 5.0 Acetic acid 0.01 Polyacrylic 0.20 155 250
320 43 acid (Mw = 4000) (Example 3-9) 5.0 Acetic acid 0.01
Polyacrylic 0.40 165 230 310 40 acid (Mw = 4000) (Comparative 5.0
Acetic acid 0.01 Polyacrylic 1.00 Evaluation stopped due to
aggregation of cerium Example 3-9) acid oxide particles (Mw =
4000)
TABLE-US-00011 TABLE 11 Polishing result SiO.sub.2 remaining
Organic acid A Polymer compound B film Mixing Mixing Polishing
thickness SiN amount amount period Dishing difference loss No. pH
Name (mass %) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.]
(Comparative 3.5 Succinic acid 0.01 Polyacrylic 0.10 Evaluation
stopped due to aggregation of cerium Example 4-1) acid oxide
particles (Mw = 4000) (Example 4-2) 4.5 Succinic acid 0.01
Polyacrylic 0.10 170 280 350 50 acid (Mw = 4000) (Example 4-1) 5.0
Succinic acid 0.01 Polyacrylic 0.10 155 330 370 55 acid (Mw = 4000)
(Example 4-3) 6.0 Succinic acid 0.01 Polyacrylic 0.10 155 320 400
60 acid (Mw = 4000) (Comparative 8.0 Succinic acid 0.01 Polyacrylic
0.10 150 840 820 50 Example 4-2) acid (Mw = 4000) (Comparative 9.0
Succinic acid 0.01 Polyacrylic 0.10 145 980 940 55 Example 4-3)
acid (Mw = 4000) (Comparative 5.0 None -- Polyacrylic 0.10 135 700
750 125 Example 4-4) acid (Mw = 4000)
TABLE-US-00012 TABLE 12 Polishing result SiO.sub.2 remaining
Organic acid A Polymer compound B film Mixing Mixing Polishing
thickness SiN amount amount period Dishing difference loss No. pH
Name (mass %) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.]
(Comparative 5.0 None -- Polyacrylic 0.10 135 700 750 125 Example
4-4) acid (Mw = 4000) (Comparative 5.0 Succinic acid 0.0001
Polyacrylic 0.10 140 650 700 115 Example 4-5) acid (Mw = 4000)
(Example 4-4) 5.0 Succinic acid 0.001 Polyacrylic 0.10 148 390 430
58 acid (Mw = 4000) (Example 4-1) 5.0 Succinic acid 0.01
Polyacrylic 0.10 155 330 370 55 acid (Mw = 4000) (Example 4-5) 5.0
Succinic acid 0.1 Polyacrylic 0.10 165 280 330 48 acid (Mw = 4000)
(Example 4-6) 5.0 Succinic acid 1 Polyacrylic 0.10 180 280 300 48
acid (Mw = 4000) (Comparative 5.0 Succinic acid 10 Polyacrylic 0.10
Evaluation stopped due to aggregation of cerium Example 4-6) acid
oxide particles (Mw = 4000)
TABLE-US-00013 TABLE 13 Polishing result SiO.sub.2 remaining
Organic acid A Polymer compound B film Mixing Mixing Polishing
thickness SiN amount amount period Dishing difference loss No. pH
Name (mass %) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.]
(Comparative 5.0 Succinic acid 0.01 None -- 140 640 740 240 Example
4-7) (Comparative 5.0 Succinic acid 0.01 Polyacrylic 0.001 145 580
670 190 Example 4-8) acid (Mw = 4000) (Example 4-7) 5.0 Succinic
acid 0.01 Polyacrylic 0.01 150 350 420 55 acid (Mw = 4000) (Example
4-1) 5.0 Succinic acid 0.01 Polyacrylic 0.10 155 330 370 55 acid
(Mw = 4000) (Example 4-8) 5.0 Succinic acid 0.01 Polyacrylic 0.20
155 280 340 50 acid (Mw = 4000) (Example 4-9) 5.0 Succinic acid
0.01 Polyacrylic 0.40 170 260 330 48 acid (Mw = 4000) (Comparative
5.0 Succinic acid 0.01 Polyacrylic 1.00 Evaluation stopped due to
aggregation of cerium Example 4-9) acid oxide particles (Mw =
4000)
TABLE-US-00014 TABLE 14 Polishing result SiO.sub.2 remaining
Organic acid A Polymer compound B film Mixing Mixing Polishing
thickness SiN amount amount period Dishing difference loss No. pH
Name (mass %) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.]
(Comparative 3.5 Maleic acid 0.01 Polyacrylic 0.10 Evaluation
stopped due to aggregation of cerium Example 5-1) acid oxide
particles (Mw = 4000) (Example 5-2) 4.5 Maleic acid 0.01
Polyacrylic 0.10 150 260 330 52 acid (Mw = 4000) (Example 5-1) 5.0
Maleic acid 0.01 Polyacrylic 0.10 140 320 340 50 acid (Mw = 4000)
(Example 5-3) 6.0 Maleic acid 0.01 Polyacrylic 0.10 135 310 380 52
acid (Mw = 4000) (Comparative 8.0 Maleic acid 0.01 Polyacrylic 0.10
130 830 810 50 Example 5-2) acid (Mw = 4000) (Comparative 9.0
Maleic acid 0.01 Polyacrylic 0.10 130 930 870 60 Example 5-3) acid
(Mw = 4000) (Comparative 5.0 None -- Polyacrylic 0.10 135 700 750
120 Example 5-4) acid (Mw = 4000)
TABLE-US-00015 TABLE 15 Polishing result SiO.sub.2 remaining
Organic acid A Polymer compound B film Mixing Mixing Polishing
thickness SiN amount amount period Dishing difference loss No. pH
Name (mass %) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.]
(Comparative 5.0 None -- Polyacrylic 0.10 135 700 750 120 Example
5-4) acid (Mw = 4000) (Comparative 5.0 Maleic acid 0.0001
Polyacrylic 0.10 135 590 640 105 Example 5-5) acid (Mw = 4000)
(Example 5-4) 5.0 Maleic acid 0.001 Polyacrylic 0.10 140 370 410 52
acid (Mw = 4000) (Example 5-1) 5.0 Maleic acid 0.01 Polyacrylic
0.10 140 320 340 50 acid (Mw = 4000) (Example 5-5) 5.0 Maleic acid
0.1 Polyacrylic 0.10 155 240 290 48 acid (Mw = 4000) (Example 5-6)
5.0 Maleic acid 1 Polyacrylic 0.10 170 220 270 50 acid (Mw = 4000)
(Comparative 5.0 Maleic acid 10 Polyacrylic 0.10 Evaluation stopped
due to aggregation of cerium Example 5-6) acid oxide particles (Mw
= 4000)
TABLE-US-00016 TABLE 16 Polishing result SiO.sub.2 remaining
Organic acid A Polymer compound B film Mixing Mixing Polishing
thickness SiN amount amount period Dishing difference loss No. pH
Name (mass %) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.]
(Comparative 5.0 Maleic acid 0.01 None -- 120 580 680 230 Example
5-7) (Comparative 5.0 Maleic acid 0.01 Polyacrylic 0.001 132 570
620 180 Example 5-8) acid (Mw = 4000) (Example 5-7) 5.0 Maleic acid
0.01 Polyacrylic 0.01 136 340 400 58 acid (Mw = 4000) (Example 5-1)
5.0 Maleic acid 0.01 Polyacrylic 0.10 140 320 340 50 acid (Mw =
4000) (Example 5-8) 5.0 Maleic acid 0.01 Polyacrylic 0.20 150 250
310 44 acid (Mw = 4000) (Example 5-9) 5.0 Maleic acid 0.01
Polyacrylic 0.40 160 230 310 50 acid (Mw = 4000) (Comparative 5.0
Maleic acid 0.01 Polyacrylic 1.00 Evaluation stopped due to
aggregation of cerium Example 5-9) acid oxide particles (Mw =
4000)
TABLE-US-00017 TABLE 17 Polishing result SiO.sub.2 remaining
Organic acid A Polymer compound B film Mixing Mixing Polishing
thickness SiN amount amount period Dishing difference loss No. pH
Name (mass %) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.]
(Comparative 3.5 Propionic acid 0.01 Polyacrylic 0.10 Evaluation
stopped due to aggregation of cerium Example 6-1) acid oxide
particles (Mw = 4000) (Example 6-2) 4.5 Propionic acid 0.01
Polyacrylic 0.10 160 250 330 44 acid (Mw = 4000) (Example 6-1) 5.0
Propionic acid 0.01 Polyacrylic 0.10 150 310 360 60 acid (Mw =
4000) (Example 6-3) 6.0 Propionic acid 0.01 Polyacrylic 0.10 150
330 390 60 acid (Mw = 4000) (Comparative 8.0 Propionic acid 0.01
Polyacrylic 0.10 140 840 780 55 Example 6-2) acid (Mw = 4000)
(Comparative 9.0 Propionic acid 0.01 Polyacrylic 0.10 138 940 910
60 Example 6-3) acid (Mw = 4000) (Comparative 5.0 None --
Polyacrylic 0.10 135 700 750 120 Example 6-4) acid (Mw = 4000)
TABLE-US-00018 TABLE 18 Polishing result SiO.sub.2 remaining
Organic acid A Polymer compound B film Mixing Mixing Polishing
thickness SiN amount amount period Dishing difference loss No. pH
Name (mass %) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.]
(Comparative 5.0 None -- Polyacrylic 0.10 135 700 750 120 Example
6-4) acid (Mw = 4000) (Comparative 5.0 Propionic acid 0.0001
Polyacrylic 0.10 142 630 660 110 Example 6-5) acid (Mw = 4000)
(Example 6-4) 5.0 Propionic acid 0.001 Polyacrylic 0.10 146 380 420
55 acid (Mw = 4000) (Example 6-1) 5.0 Propionic acid 0.01
Polyacrylic 0.10 150 310 360 60 acid (Mw = 4000) (Example 6-5) 5.0
Propionic acid 0.1 Polyacrylic 0.10 158 260 310 42 acid (Mw = 4000)
(Example 6-6) 5.0 Propionic acid 1 Polyacrylic 0.10 165 260 300 40
acid (Mw = 4000) (Comparative 5.0 Propionic acid 10 Polyacrylic
0.10 Evaluation stopped due to aggregation of cerium Example 6-6)
acid oxide particles (Mw = 4000)
TABLE-US-00019 TABLE 19 Polishing result SiO.sub.2 remaining
Organic acid A Polymer compound B film Mixing Mixing Polishing
thickness SiN amount amount period Dishing difference loss No. pH
Name (mass %) Name (mass %) [s] [.ANG.] [.ANG.] [.ANG.]
(Comparative 5.0 Propionic acid 0.01 None -- 130 650 720 210
Example 6-7) (Comparative 5.0 Propionic acid 0.01 Polyacrylic 0.001
142 580 690 180 Example 6-8) acid (Mw = 4000) (Example 6-7) 5.0
Propionic acid 0.01 Polyacrylic 0.01 145 350 390 62 acid (Mw =
4000) (Example 6-1) 5.0 Propionic acid 0.01 Polyacrylic 0.10 150
310 360 60 acid (Mw = 4000) (Example 6-8) 5.0 Propionic acid 0.01
Polyacrylic 0.20 156 270 320 48 acid (Mw = 4000) (Example 6-9) 5.0
Propionic acid 0.01 Polyacrylic 0.40 165 260 320 50 acid (Mw =
4000) (Comparative 5.0 Propionic acid 0.01 Polyacrylic 1.00
Evaluation stopped due to aggregation of cerium Example 6-9) acid
oxide particles (Mw = 4000)
LIST OF REFERENCE SIGNS
[0102] 1 . . . wafer; 2 . . . silicon nitride film; 3 . . . silicon
oxide film formed by plasma TEOS; 4 . . . depth of trench portion;
5 . . . thickness of silicon oxide film of trench portion after
polishing; 6 . . . dishing amount
* * * * *