U.S. patent application number 10/084185 was filed with the patent office on 2003-01-23 for metal polish composition and polishing method.
Invention is credited to Matsumi, Yasuo, Ueda, Kazumasa.
Application Number | 20030017785 10/084185 |
Document ID | / |
Family ID | 27346152 |
Filed Date | 2003-01-23 |
United States Patent
Application |
20030017785 |
Kind Code |
A1 |
Ueda, Kazumasa ; et
al. |
January 23, 2003 |
Metal polish composition and polishing method
Abstract
A metal polish composition comprising a chelate resin particle
and an inorganic particle and a polishing method of a metal with
said metal polish composition.
Inventors: |
Ueda, Kazumasa;
(Tsukuba-shi, JP) ; Matsumi, Yasuo; (Tsukuba-shi,
JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
27346152 |
Appl. No.: |
10/084185 |
Filed: |
February 28, 2002 |
Current U.S.
Class: |
451/41 ;
257/E21.304 |
Current CPC
Class: |
C23F 3/00 20130101; C09G
1/02 20130101; H01L 21/3212 20130101 |
Class at
Publication: |
451/41 |
International
Class: |
B24B 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 2, 2001 |
JP |
2001-057925 |
Jul 10, 2001 |
JP |
2001-208980 |
Aug 2, 2001 |
JP |
2001-234645 |
Claims
What is claimed is:
1. A metal polish composition comprising a chelate resin particle
and an inorganic particle.
2. The metal polish composition according to claim 1, wherein the
composition further comprises a polishing accelerator.
3. The metal polish composition according to claim 2, wherein the
polishing accelerator is nitric acid or nitrate.
4. The metal polish composition according to claim 2, wherein the
polishing accelerator is nitric acid or ammonium nitrate.
5. The metal polish composition according to claim 1, wherein the
chelate resin particle is a chelate resin particle having a
functional group containing at least one atom selected from the
group consisting of an oxygen atom, nitrogen atom, sulfur atom and
phosphorus atom.
6. The metal polish composition according to claim 1, wherein the
chelate resin particle is a chelate resin particle having at least
one functional group selected from the group consisting of an
aminocarboxylate group, aminophosphonate group and iminodiacetate
group.
7. The metal polish composition according to claim 1, wherein the
functional group of the chelate resin particle is a functional
group having at least one counter ion selected from the group
consisting of a hydrogen ion and ammonium ions represented by the
following general formula: +NR.sub.1R.sub.2R.sub.3R.sub.4 wherein,
R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each independently represent
a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a
benzyl group.
8. The metal polish composition according to claim 7, wherein
R.sub.1, R.sub.2, R.sub.3 and R.sub.4 represent a hydrogen
atom.
9. The metal polish composition according to claim 1, wherein the
chelate resin particle is a particle having an average particle
size of 1.0 .mu.m or less.
10. The metal polish composition according to claim 1, wherein the
zeta potential of a chelate resin particle and the zeta potential
of an inorganic particle are in the same sign.
11. The metal polish composition according to claim 1, wherein the
inorganic particle is colloidal silica.
12. The metal polish composition according to claim 1, wherein a
ratio of average particle sizes (A/B) is 30 or more when the
average particle size of chelate resin particles is represented by
A and the average particle size of inorganic particles is
represented by B.
13. The metal polish composition according to claim 2, wherein the
composition further comprises an oxidizer.
14. The metal polish composition according to claim 13, wherein the
oxidizer is hydrogen peroxide.
15. The metal polish composition according to claim 1, wherein an
aqueous solution has a pH of 3 to 9 when made into an aqueous
solution.
16. The metal polish composition according to claim 1, wherein the
metal is a metal containing tantalum.
17. The metal polish composition according to claim 1, wherein the
metal is a metal tantalum or tantalum nitride.
18. A polishing method of a metal with the metal polish composition
according to claim 1.
19. A polishing method of a metal film of a semiconductor device
with the metal polish composition according to claim 1.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a metal polish
composition.
[0003] 2. Description of the Related Art
[0004] Recently, there are various fine processing technologies
studied and developed for high integration and high performance of
LSI. Among them, a chemical mechanical polishing (hereinafter,
abbreviated as CMP) method combining a chemical action between a
polish and a body to be polished and a mechanical action of a
polishing particle in a polish is a technology important for
planarizing of an insulating interlayer, formation of a metal plug,
formation of an embedded metal wiring, separation of an embedded
element and the like, and therefore investigated variously.
[0005] For example, JP-A No. 10-310766 discloses a polish
composition composed of a polish such as silicon dioxide and the
like, an ammonium compound and water, and also discloses that a
chelate compound may also be added. However, since this chelate
compound is added for the purpose of holding and stabilizing the
quality of a product, when polishing was conducted using said
polish composition, satisfactory polishing speed could not be
obtained.
[0006] JP-A No. 4-363385 discloses a polish composition composed of
a chelate compound, alumina, aluminum salt and water, and JP-A No.
11-21545 discloses a polish composition composed of a chelate
compound, a polish such as silicon dioxide and the like, a metal
salt and water. However, also when polishing was conducted using
said polish compositions, satisfactory polishing speed could not be
obtained.
SUMMARY OF THE INVENTION
[0007] An object of the present invention is to provide a metal
polish composition which can polish metals at high speed.
[0008] The present inventors have intensively studied for a metal
polish composition having no problems as described above and
resultantly found that when a metal polish composition containing a
chelate resin particle and an inorganic particle is used for
polishing of a metal film of a semiconductor device, the metal can
be polished at high speed, and have completed the present
invention.
[0009] Namely, the present invention relates to a metal polish
composition comprising a chelate resin particle and an inorganic
particle.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0010] The present invention will be described in detail below.
[0011] The metal polish composition of the present invention is
characterized in that it comprises a chelate resin particle and an
inorganic particle.
[0012] A chelate resin particle carries on the surface thereof a
polydentate ligand having a plurality of coordinated atoms forming
a complex with a metal. In general, when a polydentate ligand
having two or more coordinated atoms is bonded to a metal ion, a
chelate ring is formed, and stability increases higher than that of
a complex coordinating a monodentate ligand, consequently, an
ability of arresting a metal ion to be polished increases and a
chemical action can be increased.
[0013] As the functional group carried on a chelate resin particle,
functional groups containing at least one atom selected from the
group consisting of an oxygen atom, nitrogen atom, sulfur atom and
phosphorus atom are listed.
[0014] As the functional group, for example, an aminocarboxylate
group, aminophosphonate group, iminodiacetate group and the like
are mentioned and an iminodiacetate group is preferable from the
standpoint of an ability of arresting a metal ion.
[0015] As the chelate resin particle having these functional
groups, that of Na type in which a counter ion of a functional
group is a sodium ion is generally used, and when applied to a
semiconductor production process, a sodium ion exerts a reverse
influence on device properties by diffusion into an insulating
film, and the like, therefore, there is preferably used as a
counter ion, in the present invention, a hydrogen ion (H type) or
an ammonium ion (ammonium type) represented by the following
general formula having little influence on a semiconductor
device.
.sup.+NR.sub.1R.sub.2R.sub.3R.sub.4
[0016] In the formula, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each
independently represent a hydrogen atom, an alkyl group having 1 to
5 carbon atoms or a benzyl group.
[0017] R.sub.1, R.sub.2, R.sub.3 and R.sub.4 represent preferably a
hydrogen atom or an alkyl group having 1 to 5 carbon atoms, more
preferably a hydrogen atom. Examples of saturated alkyl group
having 1 to 5 carbon atoms include a methyl group, ethyl group,
propyl group, isopropyl group, butyl group, isobutyl group,
sec-butyl group, tert-butyl group, pentyl group, isopentyl group,
neopentyl group, tert-pentyl group and the like.
[0018] Chelate resin particles having an aminocarboxylate group,
aminophosphonate group and iminodiacetate group as a functional
group can be produced by known methods. For example, there are
mentioned a method in which a monomer having the intended
functional group is polymerized, a method in which a functional
group carried on a polymer particle polymerized is chemically
converted into the intended functional group, and other
methods.
[0019] Also when at least one selected from the group consisting of
the H type and the ammonium types of the above-mentioned general
formula is used as a counter ion of a functional group, known
methods can be applied. For example, there are mentioned a method
in which the intended counter ion is formed from the stage of raw
materials, a method in which other counter ion is converted into
the intended counter ion by an ion exchange method, and other
methods. In the case of the ion exchange method, it is possible
that, for example, chelate resin particles produced in which a
counter ion is in the form of Na type are filled in a column and a
hydrochloric acid aqueous solution is passed through this column to
convert it into a H type, and an amine aqueous solution is further
passed through this to convert it into an ammonium type. In the ion
exchange method, it is also possible to conduct batch-wise
treatment by stirring and the like in addition to the method of
passing through a column.
[0020] Though it is preferable that a functional group of a chelate
resin particle is present on the surface of the resin particle,
even if not present on the surface of a particle, if functional
groups arresting a metal can be exposed on the surface and allowed
to contact with a metal to be polished by breaking of particles or
peeling of a coating film due to stress in polishing, and the like,
those functional groups are preferably used because the same effect
is obtained.
[0021] Chelate resin particles preferably have an average particle
size of 1.0 .mu.m or less. When the average particle size of the
particles is 1.0 .mu.m or less, process precision of the polishing
surface is further improved, desirably. Here, the term average
particle size means an average particle size measured by a dynamic
light scattering method (average secondary particle size) in the
present invention.
[0022] Though chelate resin particles having an average particle
size of 1.0 .mu.m or less can be produced directly by
polymerization, these particles can be obtained also by
wet-grinding polymer particles having an average particle size of
over 1.0 .mu.m.
[0023] In this wet grinding, known grinding apparatuses such as,
for example, a vibration mill, ball mill and the like can be used.
It is preferable to use zirconia or polymer in a liquid contact
portion to prevent metal contamination from a grinding apparatus,
and the like. Further, if necessary, it may also be permissible to
classify and control coarse particles into desired particle sizes,
by operations such as wet gravitational precipitation, centrifugal
precipitation, filtering and the like.
[0024] Conducting coarse grinding treatment by dry grinding before
effecting wet grinding is suitable since grinding efficiency in wet
grinding can be enhanced. For the dry grinding method, known
grinding apparatuses such as, for example, a jaw crushed, gyratory
crusher, roll crusher, edge runner, hammer crusher, ball mill, jet
mill, disk crusher and the like can be used. For prevention of
metal contamination from a grinding apparatus, and the like, it is
preferable to use zirconia or polymer in a contact portion. If
necessary, it may also be permissible to classify and control
coarse particles into desired particle sizes, by apparatuses such
as a dry mode wind force classification apparatus and the like.
[0025] Though it is preferable that at least one selected from the
group consisting of the H type and the ammonium types of the
above-mentioned general formula is used as a counter ion of a
functional group in a chelate resin to be wet-ground, it may also
permissible, when the counter ion is not of the H type or ammonium
type, to convert the counter ion into the H type or ammonium type
by ion exchange. For example, a H type can be obtained by
wet-grinding a chelate resin of Na type, then, adding a protonic
acid such as hydrochloric acid, nitric acid and the like to free a
sodium ion, and removing a sodium ion by filtration through a film,
and the like. Further, an ammonium type can be obtained by adding
an amine to thus obtained H type.
[0026] The concentration of chelate resin particles in the polish
composition of the present invention is preferably from 0.1 to 20%
by weight. When the concentration of chelate resin particles is
less than 0.1% by weight, there is a tendency that sufficient
polishing speed cannot be obtained, on the other hand, when the
concentration of chelate resin particles is over 20% by weight,
there is a tendency that improvement in polishing speed
corresponding to the addition concentration is not recognized.
[0027] The zeta potential of a chelate resin particle and the zeta
potential of an inorganic particle in the polish composition of the
present invention are preferably in the same sign, and it is more
preferable that both of them have negative zeta sign. When the zeta
potential of a chelate resin particle and the zeta potential of an
inorganic particle are in reverse sign each other, there is a
tendency that sufficient polishing speed cannot be attained. The
zeta potential was measured by a zeta potential measuring apparatus
of laser doppler mode (trade name: Coulter DELSA 440SX,
manufactured by Coulter).
[0028] As the inorganic particle used in the present invention, for
example, inorganic particles made of metal oxides such as silica,
alumino silicate, cerium oxide, manganese dioxide, zirconia and the
like are mentioned. Of these inorganic particles, a silica particle
is preferable since the hardness there of is lower than that of
other inorganic particles and consequently scratch is not easily
occurs on a metal film, and the particle does not easily
precipitate due to its specific gravity near that of water, and
colloidal silica is more preferable since it is cheap and does not
cause scratch easily since the form of this particle is near
sphere. These inorganic particles may be used alone or in
combination of two or more.
[0029] If the average particle size of chelate resin particles is
represented by A and the average particle size of inorganic
particles is represented by B, the ratio of average particle sizes
(A/B) is preferably 30 or more. When the ratio of average particle
sizes (A/B) is less than 30, the effect of the present invention
tends to become smaller.
[0030] The concentration of inorganic particles in the polish
composition of the present invention is not particularly
restricted, and preferably 0.1% by weight or more and less than 6%
by weight for improving the ratio of the polishing speed of a metal
film to the polishing speed of an insulating film, and preferably
6% by weight or more for further improving the polishing speed of a
metal film. When the concentration of inorganic particles is less
than 0.1% by weight, there is a tendency that sufficient polishing
speed cannot be obtained.
[0031] The polish composition of the present invention may further
contain a polishing accelerator, and as this polishing accelerator,
for example, nitric acid and salts thereof are listed.
Specifically, nitric acid and, an ammonium salt, sodium salt,
potassium salt, lithium salt, beryllium salt, magnesium salt and
calcium salts of nitric acid are listed. However, when a substrate
applied is a silicon substrate for semiconductor integrated circuit
or the like, nitric acid or ammonium nitrate is preferably used to
prevent contamination by an alkaline metals, alkaline earth metals
and the like.
[0032] The concentration of the polishing accelerator in the polish
composition of the present invention is preferably from 0.1 to 20%
by weight. When the concentration of the polishing accelerator is
less than 0.1% by weight, there is a tendency that sufficient
polishing speed cannot be obtained, on the other hand, when the
concentration of the polishing accelerator is over 20% by weight,
there is a tendency that improvement in polishing speed
corresponding to the addition concentration is not recognized.
[0033] The polish composition of the present invention is usually
dispersed in water and used in the form of slurry, and pH thereof
is preferably from 3 to 9, more preferably from 4 to 8.
[0034] To the polish composition, a pH regulator may be added, and
as the pH regulator, known acids and alkalis can be used, and it is
preferable to use acids and alkalis such as nitric acid, phosphoric
acid, sulfuric acid, ammoniumhydroxide, amine and the like
containing no metal ion.
[0035] To the polish composition of the present invention, a
surfactant can also be added for the purpose of preventing
precipitation of abrasive grains, keeping the quality of a product,
providing stability for a long period of time, preventing scratch
and dishing, and the like.
[0036] As the surfactant, anionic, cationic, nonionic and
ampholytic surfactants can be used, and two or more of them can
also be used in combination.
[0037] To the polish composition of the present invention, a
corrosion inhibitor and the like can also be added so as not to
generate scratch and dishing and the like depending on the kind of
a film to be polished. As the corrosion inhibitor, known corrosion
inhibitors can be used, and it is preferable to use benzotriazole
and benzotriazole derivatives. The concentration of the corrosion
inhibitor is preferably in the range from about 0.01 to 1.0% by
weight based on the composition.
[0038] The speed of polishing a metal film can be improved by
further compounding an oxidizing agent into the polish composition
of the present invention.
[0039] As the oxidizing agent, for example, known oxidizing agents
such as hydrogen peroxide, hydroiodic acid, hydroiodate and the
like are listed, and of them, hydrogen peroxide is preferable.
[0040] The content of the oxidizing agent is usually from about 0.1
to 15% by weight based on the composition. When the content of the
oxidizing agent is less than 0.1% by weight, there is a tendency
that an effect of improving polishing speed is not easily
manifested, on the other hand, when over 15% by weight, there is a
tendency that improvement in polishing speed corresponding to the
addition concentration is not recognized.
[0041] In preparation of the polish composition of the present
invention, mixing order and the like are not particularly
restricted. When dispersed in water to give slurry, known methods,
for example, dispersion methods using a homogenizer, ultrasonic
wave, wet medium mill and the like can be applied.
[0042] When an oxidizer is compound, all components may be mixed
previously, alternatively, an oxidizer and other components are
separately prepared and both of them are mixed in use to give a
composition of the present invention,
[0043] Further, it may also be permissible that a liquid
concentrate of relative high concentration of the polish
composition of the present invention is prepared and diluted in use
and used in actual polish processing.
[0044] The polish composition of the present invention thus
obtained is suitably used for polishing a metal film in production
of a semiconductor device.
[0045] As the metal film to be polished, a pure aluminum (Al) film,
a film made of an alloy mainly consisting of aluminum such as an
aluminum-silica-copper (AlSiCu) alloy, aluminum-copper (AlCu) alloy
and the like, a pure copper (Cu) film, tungsten film, titanium
film, titanium nitride film, tantalum film, tantalum nitride film
and the like are listed, and preferable are metal films containing
tantalum, and more preferable are a tantalum film and tantalum
nitride film.
[0046] The polishing method of the present invention is a method of
polishing a metal by chemical mechanical polishing, and
characterized in that the metal polish composition of the present
invention is used as a polish composition.
[0047] According to the polishing method of the present invention,
a metal film can be polished at high speed.
EXAMPLES
[0048] The present invention will be described below by examples,
but it is needless to say that the scope of the invention is not
limited by the examples.
[0049] As the average particle size of particles in the slurry, the
accumulated 50. diameter was measured by a micro track UPA particle
size analyzer (manufactured by Nikkiso K. K.).
[0050] The polishing speed was measured by polishing, under the
following conditions, a wafer carrying a tantalum film (Ta film)
formed by sputtering or a wafer carrying an insulating film
(SiO.sub.2 film).
[0051] [Polishing conditions]
[0052] Polishing machine: MECAPOL E-460 (PRESI)
[0053] Pad: polyurethane type
[0054] Revolution of revolving surface plate: 60 rpm
[0055] Revolution of wafer supporting table: 60 rpm
[0056] Polishing pressure: 200 g/cm.sup.2
[0057] Flow rate of polish: 100 ml/min
[0058] Polishing time: 1 minute
Example 1
[0059] (Preparation of chelate resin slurry)
[0060] 3 kg of a chelate resin having an iminodiacetate group as a
functional group (trade name: Sumichelate MC-700, manufactured by
Sumitomo Chemical Co., Ltd., counter ion : Na type) was dry-ground
by a hammer mill (revolution: 14000 rpm, screen diameter: .PHI.1.0
mm). The average particle size was 126 .mu.m. The resulted ground
product was dry-ground again by a hammer mill (revolution: 14000
rpm, screen diameter: .PHI.0.3 mm). The average particle size was
91 .mu.m. 310 g of pure water was added to 300 g of the resulted
ground product, and the mixture was subjected to ball mill
treatment under conditions of a revolution of 70 rpm and a treating
time of 30 hours using zirconia balls of 5 mm.PHI.. The average
particle size of resin particles in the resulted slurry was 0.344
.mu.m.
[0061] Thus obtained resin particle slurry was dispersed in a
buffer of 0.01 N potassium chloride water, and pH of this water
dispersion was controlled to about 2 to 11 with hydrochloric acid
or potassium hydroxide, and the zeta potential at each pH was
measured by a zeta potential measuring apparatus of laser doppler
mode (trade name: Coulter DELSA 440SX, manufactured by Coulter).
Further, inorganic particle slurry and vinyl chloride latex slurry
used in the following examples were dispersed in a buffer of 0.01 N
potassium chloride water, and each zeta potential was measured by
the same manner. The results are shown in Table 1 and FIG. 1.
1TABLE 1 Vinyl chloride Colloidal Colloidal Chelate resin latex
silica A silica B .zeta. .zeta. .zeta. .zeta. poten- poten- poten-
poten- tial tial tial tial pH (mV) pH (mV) pH (mV) pH (mV) 2.9
-44.5 2.9 10.9 3.3 -32.4 2.9 -35.9 4.3 -44.1 4.0 12.3 4.0 -35.6 3.5
-38.3 6.3 -39.3 5.2 -8.0 5.7 -40.9 6.1 -44.9 9.1 -33.0 8.5 -63.0
7.9 -42.2 8.8 -62.7 10.3 -40.2 10.0 -62.5 10.0 -48.5 10.2 -63.9
[0062] (Preparation of polish)
[0063] The resulted resin particle slurry, colloidal silica A
(average particle size: 0.010 .mu.m) as an inorganic particle, and
hydrogen peroxide as an oxidizer were formulated as shown in Table
2, then, pH of the preparation was controlled to 4 using nitric
acid, obtaining a polish. The polishing results are shown in Table
2.
[0064] The zeta potential of the chelate resin particle was about
-44 mV and the zeta potential of the colloidal silica A was about
-35.6 mV, at pH 4, read from a graph showing the correlation
between pH and zeta potential in FIG. 1, namely, they were in the
same sign.
[0065] Comparative Examples 1 and 2
[0066] A polish containing only the resin particles obtained in the
above-mentioned preparation of resin particle slurry was used as
Comparative Example 1 and a polish containing only the
above-mentioned colloidal silica A (average particle size: 0.010
.mu.m) was used as Comparative Example 2, and formulation was
effected using these polishes as shown in Table 2, then, pH was
controlled to 4 using nitric acid, obtaining polishes. The
polishing results are shown in Table 2.
[0067] Comparative Examples 3 and 4
[0068] Vinyl chloride latex slurry (average particle size: 0.349
.mu.m) was used instead of the slurry of resin particles obtained
by grinding the chelate resin having an iminodiacetate group as a
functional group, and a polish containing only the vinyl chloride
latex was used as Comparative Example 3 and a polish containing a
mixed system with the above-mentioned colloidal silica A was used
as Comparative Example 4, and formulation was effected using these
polishes as shown in Table 2, then, pH was controlled to 4 using
nitric acid, obtaining polishes. The polishing results are shown in
Table 2.
[0069] The zeta potential of the vinyl chloride latex was +12.3 mV
and the zeta potential of the colloidal silica A was about -35.6
mV, at pH 4, read from a graph showing the correlation between pH
and zeta potential in FIG. 1, namely, they were in different
signs.
Example 2
[0070] The resin particle slurry resulted in Example 1, colloidal
silica B (average particle size: 0.122 .mu.m) as an inorganic
particle, and hydrogen peroxide as an oxidizer were formulated as
shown in Table 2, then, pH of the preparation was controlled to 4
using nitric acid, obtaining a polish. The polishing results are
shown in Table 2.
[0071] The zeta potential of the chelate resin particle was about
-44 mV and the zeta potential of the colloidal silica B was about
-40 mV, at pH 4, read from a graph showing the correlation between
pH and zeta potential in FIG. 1, namely, they were in the same
sign.
[0072] Comparative Example 5
[0073] A polish containing only the above-mentioned colloidal
silica B (average particle size: 0.122 .mu.m) was used as
Comparative Example 5, and formulation was effected using the
polish as shown in Table 2, then, pH was controlled to 4 using
nitric acid, obtaining a polish. The polishing results are shown in
Table 2.
2TABLE 2 Slurry Comparative composition Ex. Comparative Ex. Ex. Ex.
(wt %) 1 1 2 3 4 2 5 Resin particle 5.0 10.0 10.0 5.0 5.0 Inorganic
5.0 10.0 5.0 5.0 10.0 particle Oxidizer 1.5 1.5 1.5 1.5 1.5 1.5 1.5
Polishing speed 724 37 214 6 212 350 230 (.ANG./min)
[0074] As shown in Table 2, a tantalum film could be polished at
high speed, by polishing using a polish containing a chelate resin
particle and an inorganic particle in admixture. Scratch was not
observed on the surface after polishing. On the other hand, in the
cases of a polish containing only a chelate resin particle and a
polish containing only an inorganic particle, the speed of
polishing a tantalum film was low. Also in polishing with a polish
containing the other resin than a chelate resin, and an inorganic
particle in admixture, the speed of polishing a tantalum film was
low.
Example 3
[0075] (Preparation of polish)
[0076] The resin particle slurry obtained in Example 1, colloidal
silica A (average particle size: 0.010 .mu.m) as an inorganic
particle, nitric acid as a polish accelerator and hydrogen peroxide
as an oxidizer were formulated as shown in Table 3, obtaining a
polish composition. The results are shown in Table 3.
Example 4
[0077] A polish composition was obtained in the same manner as in
Example 3 except that nitric acid was replaced by ammonium nitrate.
The results are shown in Table 3.
[0078] Comparative Example 6
[0079] The resin particle obtained in the above-mentioned
preparation of resin particle slurry, ammonium nitrate as a polish
accelerator, and hydrogen peroxide as an oxidizer were formulated
as shown in Table 3, obtaining a polish composition. The results
are shown in Table 3.
[0080] Comparative Example 7
[0081] The above-mentioned colloidal silica A (average particle
size: 0.010 .mu.m), ammonium nitrate as a polish accelerator, and
hydrogen peroxide as an oxidizer were formulated as shown in Table
3, obtaining a polish composition. The results are shown in Table
3.
[0082] Comparative Example 8
[0083] Glycine as a chelate compound instead of the slurry of resin
particles obtained by grinding a chelate resin, and ammonium
nitrate as a polish accelerator, and hydrogen peroxide as an
oxidizer were formulated as shown in Table 3, obtaining a polish
composition. The results are shown in Table 3.
Example 5
[0084] The resin particle slurry obtained in Example 1, the
colloidal silica B (average particle size: 0.122 .mu.m) as an
inorganic particle, ammonium nitrate as a polish accelerator, and
hydrogen peroxide as an oxidizer were formulated as shown in Table
3, obtaining a polish composition. The results are shown in Table
3.
[0085] Comparative Example 9
[0086] The above-mentioned colloidal silica B (average particle
size: 0.122 .mu.m), ammonium nitrate as a polish accelerator, and
hydrogen peroxide as an oxidizer were formulated as shown in Table
3 obtaining a polish composition. The results are shown in Table
3.
3TABLE 3 Slurry Compara- composition Ex. Comparative Ex. Ex. tive
Ex. (wt %) 3 4 6 7 8 5 9 Chelate resin 10 10 10 10 particle Chelate
10 compound Inorganic 8.3 8.3 8.3 8.3 8.3 8.3 particle Polishing
2.0 2.6 2.6 2.6 2.6 2.6 2.6 accelerator Oxidizer 2.5 2.5 2.5 2.5
2.5 2.5 2.5 pH 4.0 8.6 8.7 4.0 5.0 8.9 7.1 Polishing speed 922 632
40 355 277 480 369 (.ANG./min)
[0087] As shown in Table 3, a tantalum film could be polished at
high speed, by polishing using a polish containing a chelate resin
particle, inorganic particle and nitric arid or nitrate. Scratch
was not observed on the surface after polishing. On the other hand,
in the case of a polish containing a chelating agent instead of the
chelate resin, the speed of polishing a tantalum film was low.
Example 6
[0088] (Preparation of polish)
[0089] The resin particle slurry obtained in Example 1, colloidal
silica A (average particle size: 0.010 .mu.m) as an inorganic
particle, ammonium nitrate as a polish accelerator and hydrogen
peroxide as an oxidizer were formulated as shown in Table 4,
obtaining a polish composition. The results are shown in Table
4.
[0090] Comparative Example 10
[0091] The resin particle obtained in the above-mentioned
preparation of resin particle slurry of Example 1, ammonium nitrate
as a polish accelerator, and hydrogen peroxide as an oxidizer were
formulated as shown in Table 4, obtaining a polish composition. The
results are shown in Table 4.
[0092] Comparative Example 11
[0093] Glycine as a chelate compound instead of the resin particle
slurry in Example 1, and ammonium nitrate as a polish accelerator,
and hydrogen peroxide as an oxidizer were formulated as shown in
Table 4, obtaining a polish composition. The results are shown in
Table 4.
Example 7
[0094] (Preparation of chelate resin slurry)
[0095] 1 L of a chelate resin having an iminodiacetate group as a
functional group (trade name: Sumichelate MC-700, manufactured by
Sumitomo Chemical Co., Ltd., counter ion : Na type) was filled in a
column and washed with ultrapure water, then, 10 L of a 2 N
hydrochloric acid aqueous solution was passed through this, and
washed again with ultrapure water, to give a chelate resin of H
type. Further, 2 N ammonia water was passed through this, and
washed again with ultrapure water and dehydrated, to obtain a
chelate resin of ammonium type. 27.5 kg of a chelate resin of
ammonium type obtained by the same treatment was dry-ground by
Impeller mill (trade name: manufactured by Seishin Kigyosha K.K.).
This was conducted under grinding conditions of a rotor revolution
of 6000 rpm and a feeding rate of 15 kg/hr, to obtain 23.3 kg of a
ground product. The average particle size of the ground product was
43 .mu.m.
[0096] 6.9 kg of ultrapure water was added to 2.6 kg of the
resulted ground product and the mixture was stirred to obtain a
dispersion, and this was wet-ground by Dinosaur mill (trade name:
manufactured by Shinmal Enterprise K. K.). This was conducted under
grinding conditions of a peripheral speed of 14 m/sec. and a
feeding rate of 0.5 L/min, with 10 passes. The average particle
size of the resulted chelate resin particles was 0.32 .mu.m.
[0097] In the resulted slurry, the colloidal silica A (average
particle size: 0.010 .mu.m) as an inorganic particle, ammonium
nitrate as a polish accelerator and hydrogen peroxide as an
oxidizer were formulated as shown in Table 4, obtaining a polish
composition. The results are shown in Table 4.
4 TABLE 4 Slurry composition Ex. Comparative Ex. Ex. (wt %) 6 10 11
7 Chelate resin 1.0 1.0 1.0 particle 1.0 Chelate compound 1.0
Inorganic particle 1.0 1.0 1.0 Polishing accelerator 2.6 2.6 2.6
2.6 Oxidizer 6.0 6.0 6.0 6.0 pH 7.6 7.8 4.7 6.1 Ta Polishing speed
453 2 270 495 (.ANG./min) SiO.sub.2 Polishing speed 11 3 10 7
(.ANG./min) Ta/SiO.sub.2 selection 41 0.7 27 71 ration
[0098] As shown in Table 4, by polishing using a polish containing
a chelate resin particle, inorganic particle and polishing
accelerator in admixture, the ratio of the polishing speed of a
metal film to the polishing speed of an insulation film was high,
and a metal film could be polished selectively. Scratch was not
observed on the surface after polishing. On the other hand, in the
case of a polish containing a chelating agent instead of the
chelate resin, the ratio of the polishing speed of a metal film to
the polishing speed of an insulation film was low, and a metal film
could not be polished selectively. According to the present
invention, a metal film can be polished at high speed in producing
a semiconductor device.
BRIEF DESCRIPTION OF A DRAWING
[0099] FIG. 1
[0100] FIG. 1 illustrates a relationship between pH and zeta
potential.
* * * * *