U.S. patent application number 10/727044 was filed with the patent office on 2004-11-25 for composite material and processing method using the material.
This patent application is currently assigned to SHOWA DENKO K.K.. Invention is credited to Kashima, Shinji, Morita, Toshio, Toki, Masaharu, Yamamoto, Ryuji.
Application Number | 20040231245 10/727044 |
Document ID | / |
Family ID | 32754116 |
Filed Date | 2004-11-25 |
United States Patent
Application |
20040231245 |
Kind Code |
A1 |
Yamamoto, Ryuji ; et
al. |
November 25, 2004 |
Composite material and processing method using the material
Abstract
An abrasive composite material containing a matrix, abrasive
grains, and carbon fiber having a multi-layer structure, each fiber
filament of the carbon fiber having an outer diameter of about 2 to
about 500 nm and an aspect ratio of about 5 to about 15,000, and
including a hollow space extending along its center axis.
Preferably, the carbon fiber has a BET specific surface area of
about 4 m.sup.2/g or more; the carbon fiber has, at a carbon (002)
plane, an interlayer distance (d.sub.002) of about 0.345 nm or less
as measured by means of X-ray diffractometry; and the ratio of the
peak height (Id) of the band at 1,341 to 1,349 cm.sup.-1 in a Raman
scattering spectrum of the carbon fiber to the peak height (Ig) of
the band at 1,570 to 1,578 cm.sup.-1 in the spectrum; i.e., Id/Ig,
is about 1.5 or less. More preferably, the carbon fiber contains
branched vapor grown carbon fiber; boron is contained, in an amount
of about 0.01 to about 5 mass %, in the interior of crystals
constituting the carbon fiber; and the amount of the carbon fiber
contained in the abrasive composite material is about 2 to about 40
vol. %. When the abrasive composite material is employed,
high-precision grinding or polishing can be attained. When the
composite material is employed in a cutting tool material, the
resultant cutting tool material realizes high-speed,
high-efficiency cutting, and enables wire-cut electrical discharge
machining.
Inventors: |
Yamamoto, Ryuji; (Kanagawa,
JP) ; Toki, Masaharu; (Tokyo, JP) ; Morita,
Toshio; (Kanagawa, JP) ; Kashima, Shinji;
(Nagano, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
SHOWA DENKO K.K.
|
Family ID: |
32754116 |
Appl. No.: |
10/727044 |
Filed: |
December 4, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60432247 |
Dec 11, 2002 |
|
|
|
Current U.S.
Class: |
51/307 ; 451/28;
451/540; 51/296; 51/298; 51/308; 51/309 |
Current CPC
Class: |
B24D 3/00 20130101; B24B
37/24 20130101; B24B 37/22 20130101 |
Class at
Publication: |
051/307 ;
051/308; 051/309; 051/296; 051/298; 451/028; 451/540 |
International
Class: |
B24D 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 4, 2002 |
JP |
P2002-352510 |
Claims
What is claimed is:
1. An abrasive composite material comprising a matrix, abrasive
grains, and carbon fiber having a multi-layer structure, each fiber
filament of the carbon fiber having an outer diameter of about 2 to
about 500 nm and an aspect ratio of about 5 to about 15,000, and
including a hollow space extending along its center axis.
2. An abrasive composite material according to claim 1, wherein the
carbon fiber has a BET specific surface area of at least about 4
m.sup.2/g.
3. An abrasive composite material according to claim 1, wherein the
carbon fiber has, at a carbon (002) plane, an interlayer distance
(d.sub.002) of about 0.345 nm or less as measured by means of X-ray
diffractometry.
4. An abrasive composite material according to claim 1, wherein the
ratio of the peak height (Id) of the band at 1,341 to 1,349
cm.sup.-1 in a Raman scattering spectrum of the carbon fiber to the
peak height (Ig) of the band at 1,570 to 1,578 cm.sup.-1 in the
spectrum; i.e., Id/Ig, is about 1.5 or less.
5. An abrasive composite material according to claim 1, wherein the
carbon fiber contains branched vapor grown carbon fiber.
6. An abrasive composite material according to claim 1, wherein
boron is contained, in an amount of about 0.01 to about 5 mass %,
in the interior of crystals constituting the carbon fiber.
7. An abrasive composite material according to claim 1, wherein the
amount of the carbon fiber is about 2 to about 40 vol. % with
respect to the abrasive composite material.
8. An abrasive composite material according to claim 1, wherein the
abrasive grains are formed of at least one material selected from
among cerium oxide, silicon oxide, silicon carbide, boron carbide,
boron nitride, zirconium oxide, diamond, and sapphire.
9. An abrasive composite material according to claim 1, wherein the
matrix is formed of at least one material selected from among a
resin, a metal, and a ceramic material.
10. An abrasive composite material according to claim 9, wherein
the resin contains at least one species selected from among a
phenolic resin, a melamine resin, a polyurethane resin, an epoxy
resin, a urea resin, an unsaturated polyester resin, a silicone
resin, a polyimide resin, an epoxy resin, a cyanate ester resin,
and a benzoxazine resin.
11. A grinding wheel formed through molding of an abrasive
composite material as recited in claim 1.
12. A grinding material comprising an abrasive composite material
as recited in claim 1.
13. A polishing material comprising an abrasive composite material
as recited in claim 1.
14. A cutting tool material comprising an abrasive composite
material as recited in claim 1.
15. A cutting tool material according to claim 14, wherein the
matrix contains the carbon fiber in an amount of about 20 to about
45 vol. %.
16. A wire-cut electrical discharge machining material comprising a
cutting tool material as recited in claim 14.
17. A wire-cut electrical discharge machining method employing a
cutting tool material as recited in claim 14.
18. A method for producing a cutting tool, which employs a wire-cut
electrical discharge machining method as recited in claim 17.
19. A method for producing an electronic part, which method
comprises a step of grinding at least one species selected from
among a semiconductor, an interlayer insulating film, and a wiring
material by use of an abrasive composite material as recited in
claim 1.
20. A method for producing an electronic part, which method
comprises a step of polishing at least one species selected from
among a semiconductor, an interlayer insulating film, and a wiring
material by use of an abrasive composite material as recited in
claim 1.
21. A method for producing an electronic part according to claim 19
or 20, wherein the semiconductor is at least one species selected
from among polycrystalline silicon, single-crystal silicon, and
amorphous silicon.
Description
DETAILED DESCRIPTION OF THE INVENTION
[0001] 1. Technical Field to which the Invention Pertains
[0002] The present invention relates to a composite material
containing abrasive grains employed for grinding or polishing, such
as a wheel or a blade. More particularly, the present invention
relates to an abrasive composite material employed for precision
grinding or precision polishing of an electronic part such as a
semiconductor wafer, an interlayer insulating film, or a wiring
material by means of the fixed abrasive method; to a grinding
material or polishing material containing the composite material;
and to a method for processing an electronic part such as a
semiconductor wafer, the method employing the composite
material.
[0003] 2. Background Art
[0004] In recent years, keeping pace with the advancement in
high-performance semiconductor devices, electronic circuits have
attained increased degree of integration and miniaturization.
Successful formation of a sophisticated wiring structure on the
surface of a semiconductor substrate calls for planarization of the
imaging surface; i.e., the semiconductor substrate surface. This
process is critical for alleviating the miniaturization limit of
circuit patterns formed by photolithography, or stated differently,
the shallow focal depth.
[0005] In a generally employed method for attaining semiconductor
substrate planarization by means of chemical mechanical polishing,
a substrate supported by a carrier is rotated while a slurry
prepared by dispersing abrasive grains in an abrasive liquid is
supplied to a polishing pad, whereby the substrate is polished. For
example, a slurry for polishing an insulating film is prepared by
dispersing, in an abrasive liquid, silicon dioxide (see, for
example, Patent Document 1), cerium oxide (see, for example, Patent
Document 2), or a similar substance. Such a method, which employs a
relatively soft polishing pad in order to prevent damage to a
substrate, involves a problem in terms of low polishing speed
attributed to the abrasive grains not being held on the polishing
pad. In the case where a circuit-pattern-printed substrate is
polished, the polishing speed varies in accordance with the
distance between circuit wiring patterns, leading to occurrence of
non-uniform polishing, such as dishing or thinning. In addition,
such a method involves a problem in terms of, for example,
treatment of used abrasive grains.
[0006] In order to solve problems associated with the
aforementioned semiconductor substrate planarization method, there
has been proposed another method in which a substrate is pressed
onto a rotating disk onto which abrasive grains are fixed, and the
substrate is polished while the disk is rotated or slid (see, for
example, Patent Document 3, 4, or 5).
[0007] This method is advantageous in that a relatively high
polishing speed is achieved, by virtue of the fixed abrasive
grains.
[0008] [Patent Document 1]
[0009] Japanese Patent Application Laid-Open (kokai) No.
2001-26771
[0010] [Patent Document 2]
[0011] Japanese Patent Application Laid-Open (kokai) No.
2001-179610
[0012] [Patent Document 3]
[0013] Japanese Patent Application Laid-Open (kokai) No.
10-329031
[0014] [Patent Document 4]
[0015] Japanese Patent Application Laid-Open (kokai) No.
11-333705
[0016] [Patent Document 5]
[0017] Japanese Patent Application Laid-Open (kokai) No.
2001-49243
PROBLEMS TO BE SOLVED BY THE INVENTION
[0018] However, such a polishing method employing fixed abrasive
grains involves problems, including generation of micro-scratches
during the course of polishing, and generation of deep polishing
marks attributed to falling of abrasive grains. Such scratches
cause short circuit, thereby tending to lower the yield of the
resultant device.
[0019] In order to attain production of a high-performance
semiconductor device, precision of polishing of the surface of a
substrate must be improved, and a substrate having neither
scratches nor polishing marks must be provided.
[0020] In addition, there is required means for polishing a
substrate without forming scratches thereon and for precisely
polishing elements constituting the device, such as an interlayer
insulating film and a circuit pattern.
[0021] In view of the foregoing, the present invention has been
completed. The present invention contemplates a grinding material,
a polishing material, a grinding method, and a polishing method,
the material or the method enabling production of a substrate
having surfaces with neither scratches nor polishing marks, by
performing improved precision polishing of surfaces of, for
example, substrates, interlayer insulating films, or circuit
patterns.
[0022] Specifically, the present invention contemplates a grinding
material, a polishing material, a grinding method, and a polishing
method, the material or the method enabling suppressing falling of
abrasive grains during the course of grinding or polishing,
suppressing generation of polishing marks, reducing burden on
post-treatment of abrasive grains, and providing the grinding
material or polishing material with long lifetime.
[0023] The present invention also contemplates an abrasive
composite material which can be formed into a grinding material or
a polishing material exhibiting improved tribological
characteristics, elasticity, electrical conductivity, thermal
conductivity, and corrosion resistance, and which leads to an
improved precision in grinding or polishing of a workpiece, to
thereby reduce adverse effects caused by physical or chemical
factors during the course of processing.
[0024] The present invention further contemplates a method for
processing an electronic part, the method including grinding or
polishing an interlayer insulating film or a circuit pattern
constituting a semiconductor substrate or a electronic device, by
use of a grinding material or a polishing material comprising such
a high-performance abrasive composite material.
[0025] In particular, the present invention contemplates a method
for processing silicon, the method including grinding or polishing
silicon such as polycrystalline silicon, single-crystal silicon,
and amorphous silicon.
MEANS FOR SOLVING THE PROBLEMS
[0026] In order to solve the aforementioned problems, the present
inventors have performed studies, and as a result have invented an
abrasive composite material, a grinding wheel comprising the
composite material, a grinding material comprising the composite
material, and a polishing material comprising the composite
material, as described below. In addition, the present inventors
have invented a method for processing an electronic part, and a
method for processing silicon, the methods employing the grinding
wheel, grinding material, or polishing material.
[0027] The abrasive composite material of the present invention
contains carbon fiber and therefore exhibits excellent tribological
characteristics, elasticity, electrical conductivity, thermal
conductivity, and corrosion resistance. Therefore, when the
abrasive composite material is employed, falling of abrasive grains
is suppressed, friction resistance is reduced, non-uniform
polishing is prevented, a polished surface is highly planarized,
and high-precision grinding or polishing can be attained.
[0028] No particular limitations are imposed on the abrasive grains
or matrix employed in the abrasive composite material of the
present invention, and the abrasive grains or matrix can be formed
of a conventionally known material.
[0029] The grinding wheel, the grinding material, or the polishing
material of the present invention contains carbon fiber and
therefore exhibits excellent tribological characteristics,
elasticity, electrical conductivity, thermal conductivity, and
corrosion resistance. Therefore, when the abrasive composite
material is employed, falling of abrasive grains is suppressed,
friction resistance is reduced, non-uniform polishing is prevented,
a polished surface is highly planarized, and high-precision
grinding or polishing can be attained.
[0030] When the processing method of the present invention is
employed for grinding or polishing of silicon or a variety of
electronic parts, falling of abrasive grains is suppressed,
friction resistance is reduced, non-uniform polishing is prevented,
a polished surface is highly planarized, and high-precision
grinding or polishing can be attained.
[0031] Accordingly, the present invention provides the
following.
[0032] (1) An abrasive composite material, characterized by
comprising a matrix, abrasive grains, and carbon fiber having a
multi-layer structure, each fiber filament of the carbon fiber
having an outer diameter of 2 to 500 nm and an aspect ratio of 5 to
15,000, and including a hollow space extending along its center
axis.
[0033] (2) An abrasive composite material according to (1), wherein
the carbon fiber has a BET specific surface area of at least 4
m.sup.2/g.
[0034] (3) An abrasive composite material according to (1) or (2),
wherein the carbon fiber has, at a carbon (002) plane, an
interlayer distance (d.sub.002) of 0.345 nm or less as measured by
means of X-ray diffractometry.
[0035] (4) An abrasive composite material according to any one of
(1) through (3), wherein the ratio of the peak height (Id) of the
band at 1,341 to 1,349 cm.sup.-1 in a Raman scattering spectrum of
the carbon fiber to the peak height (Ig) of the band at 1,570 to
1,578 cm.sup.-1 in the spectrum; i.e., Id/Ig, is 1.5 or less.
[0036] (5) An abrasive composite material according to any one of
(1) through (4), wherein the carbon fiber contains branched vapor
grown carbon fiber.
[0037] (6) An abrasive composite material according to any one of
(1) through (5), wherein boron is contained, in an amount of 0.01
to 5 mass %, in the interior of crystals constituting the carbon
fiber.
[0038] (7) An abrasive composite material according to any one of
(1) through (6), wherein the amount of the carbon fiber is 5 to 40
vol. % with respect to the abrasive composite material.
[0039] (8) An abrasive composite material according to (1), wherein
the abrasive grains are formed of at least one material selected
from among cerium oxide, silicon oxide, silicon carbide, boron
carbide, boron nitride, zirconium oxide, diamond, and sapphire.
[0040] (9) An abrasive composite material according to (1), wherein
the matrix is formed of at least one material selected from among a
resin, a metal, and a ceramic material.
[0041] (10) An abrasive composite material according to (9),
wherein the resin forming the matrix contains at least one species
selected from among a phenolic resin, a melamine resin, a
polyurethane resin, an epoxy resin, a urea resin, an unsaturated
polyester resin, a silicone resin, a polyimide resin, an epoxy
resin, a cyanate ester resin, and a benzoxazine resin.
[0042] (11) A grinding wheel characterized by being formed through
molding of an abrasive composite material as recited in any one of
(1) through (10).
[0043] (12) A grinding material or a polishing material,
characterized by comprising an abrasive composite material as
recited in any one of (1) through (10).
[0044] (13) A method for processing an electronic part,
characterized by grinding or polishing a semiconductor, an
interlayer insulating film, or a wiring material by use of a
grinding wheel as recited in (11) or a grinding material or a
polishing material as recited in (12).
[0045] (14) A method for processing silicon, characterized by
grinding or polishing polycrystalline silicon, single-crystal
silicon, and amorphous silicon by use of a grinding wheel as
recited in (11) or a grinding material or a polishing material as
recited in (12).
MODES FOR CARRYING OUT THE INVENTION
[0046] The present invention will next be described in detail.
[0047] The abrasive composite material of the present invention
contains a matrix (e.g., substrate or fabric), abrasive grains, and
carbon fiber, wherein the abrasive grains and carbon powder are
fixed onto the matrix. The abrasive composite material can be
formed into, for example, a grinding wheel through molding of a
mixture of the matrix, which also serves as a binder, the abrasive
grains, and the carbon fiber; a polishing blade by fixing the
abrasive grains and carbon fiber, by use of a binder, onto the
surface of a metallic or ceramic substrate serving as the matrix;
or a polishing pad by fixing the abrasive grains and carbon fiber,
by use of a binder, onto the surface of the matrix formed of
non-woven fabric.
[0048] As used herein, the term "grinding" refers to a process for
removing a member, the process including cutting; and the term
"polishing" refers to a process for reducing irregularities on the
surface of a member, thereby smoothing the member surface. As used
herein, the terms "grinding material" and "polishing material"
refer to materials employed for the aforementioned respective
processes. Specific examples of products produced from the grinding
material or the polishing material include a grinding wheel, a
polishing wheel, a grinding blade, a polishing pad, and a
dresser.
[0049] (Abrasive Grains)
[0050] No particular limitations are imposed on the type of
abrasive grains employed in the present invention, and, in
accordance with the type of a target workpiece, the abrasive grains
may be selected from among conventionally known substances, for
example, cerium oxide, silicon oxide, aluminum oxide, titanium
oxide, zirconium oxide, silicon carbide, tungsten carbide, boron
carbide, boron nitride, diamond, sapphire, and organic fine
particles. When the abrasive composite material is employed in the
semiconductor field, the abrasive grains are particularly
preferably formed of at least one species selected from among
cerium oxide, silicon oxide, and aluminum oxide.
[0051] The size of the abrasive grains employed in the present
invention varies within a range of 0.1 to 100 .mu.m, in accordance
with the degree of surface finishing of a workpiece. Preferably,
the abrasive grains have a size of 0.3 to 50 .mu.m. When the grain
size is 0.1 .mu.m or less, protrusions of the abrasive grains
becomes small, and the polishing speed is considerably reduced,
whereas when the grain size is 100 .mu.m or more, the polishing
speed increases, but the number of polishing marks on the surface
of the resultant workpiece increases, the depth of the marks
increases, and the surface roughness of the workpiece
increases.
[0052] When the abrasive composite material is formed into a
grinding wheel, the amount of the abrasive grains added to the
composite material is preferably 3 to 30 vol. %, more preferably 5
to 20 vol. %. When the amount of the abrasive grains is 3 vol. % or
less, the polishing speed decreases, sufficient planarization fails
to be attained within a short period of time, whereas when the
amount of the abrasive grains is 30 vol. % or more, adhesion of a
resin to the abrasive grains is lowered, and falling of the
abrasive grains considerably occurs, resulting in an increase in
the number of polishing marks.
[0053] When the abrasive grains are fixed onto the surface of the
matrix, preferably, the ratio by volume of the abrasive grains to
the carbon fiber is regulated to 1:0.5 to 1:1.
[0054] (Matrix)
[0055] Examples of the matrix employed in the present invention
include resins such as plastic and rubber; ceramic materials such
as cement and glass; and metals such as pure metals and alloys.
Such a matrix may serve as a bond. The means for fixing the
abrasive grains or carbon fiber onto the matrix may be any type of
bond, such as resinoid bond, metal bond, vitrified bond, and
electroplated bond.
[0056] No particular limitations are imposed on the resin employed
in the present invention, and a known resin may be employed.
Examples of the resin which may be employed include thermosetting
resins such as polyamide, polyether, polyester, polyimide,
polysulfone, epoxy resin, unsaturated polyester, and phenolic
resin; and thermoplastic resins such as nylon, polyethylene,
polycarbonate, and polyarylate. Such a resin may be employed in
combination with a foaming agent. If desired, there may be employed
a foam regulating agent, an additive for regulating dispersion,
humidity, or wettability of the abrasive grains, or a coupling
agent for regulating the strength of bonding between the resin and
the abrasive grains.
[0057] In the case where a resin is employed as the matrix, the
resin, the abrasive grains, and the carbon fiber may be mixed
together, and the resultant mixture may be subjected to compression
molding, thereby forming a grinding wheel. Alternatively, the
abrasive grains and the carbon fiber may be fixed, by use of a
bond, onto the surface of a substrate or non-woven fabric formed of
the resin serving as the matrix.
[0058] In the case where the abrasive grains and the carbon fiber
are fixed onto the surface of a metallic or ceramic matrix, metal
bond can be employed. The metal bond may be an alloy of copper,
tin, iron, nickel, cobalt, or a similar metal. Vitrified bond is a
ceramic or glassy bond (inorganic bond) prepared through sintering
at 800 to 1,000.degree. C. Electroplated bond is means for fixing
the abrasive grains through electroplating.
[0059] (Carbon Fiber)
[0060] The carbon fiber employed in the present invention is
preferably vapor grown carbon fiber. In general, vapor grown carbon
fiber can be produced by thermally decomposing an organic compound
by use of an organo-transition metallic compound.
[0061] Examples of the organic compound which may serve as a raw
material of the vapor grown carbon fiber include toluene, benzene,
naphthalene, ethylene, acetylene, ethane, gasses such as natural
gas and carbon monoxide, and mixtures thereof. Of these, aromatic
hydrocarbons such as toluene and benzene are preferred.
[0062] An organo-transition metallic compound contains a transition
metal serving as a catalyst, and is an organic compound containing,
as a transition metal, a metal belonging to Group IVa, Va, VIa,
VIIa, or VIII of the periodic table. An organo-transition metallic
compound such as ferrocene or nickelocene is preferred.
[0063] The vapor grown carbon fiber is produced through the
following procedure: the aforementioned organic compound and
organo-transition metallic compound are gasified, and mixed with a
reducing gas (e.g., hydrogen) which has been preliminarily heated
to 500 to 1,300.degree. C.; and the resultant mixture is fed into a
reaction furnace heated to 800 to 1,300.degree. C., to thereby
allow reaction to proceed.
[0064] In order to enhance adhesion of the vapor grown carbon fiber
to the matrix, preferably, the carbon fiber is subjected to thermal
treatment in an inert atmosphere at 900 to 1,300.degree. C., to
thereby remove organic substances (e.g., tar) deposited on the
surface of the carbon fiber.
[0065] In order to further enhance adhesion of the vapor grown
carbon fiber to the matrix, the carbon fiber may be subjected to
thermal treatment in an oxidative atmosphere at 300 to 450.degree.
C., or may be activated by use of, for example, carbon dioxide gas
or potassium hydroxide, to thereby increase the area of a portion
of the carbon fiber that adheres to the matrix.
[0066] The surface area of the vapor grown carbon fiber can be
increased by means of dry milling employing, for example, a
vibration mill or a jet mill, or by means of wet milling employing,
for example, a bead mill.
[0067] In order to enhance affinity of the vapor grown carbon fiber
to the matrix, the carbon fiber surface or the entirety of the
carbon fiber may be subjected to, for example, fluorination or
oxidation.
[0068] In order to improve characteristics (e.g., electrical
conductivity and thermal conductivity) of the vapor grown carbon
fiber, the carbon fiber may be subjected to thermal treatment in an
inert atmosphere at 2,000 to 3,500.degree. C., to thereby enhance
crystallinity thereof. In order to further enhance crystallinity
and electrical conductivity of the vapor grown carbon fiber, the
carbon fiber may be mixed with a boron compound such as boron
carbide (B.sub.4C), boron oxide (B.sub.2O.sub.3), elemental boron,
boric acid (H.sub.3BO.sub.3), or a borate, and the resultant
mixture may be subjected to thermal treatment in an inert
atmosphere at 2,000 to 3,500.degree. C., such that boron (B) is
contained, in an amount of 0.01 to 5 mass %, in carbon crystals
constituting the carbon fiber.
[0069] The vapor grown carbon fiber may be thermally treated by use
of any furnace, so long as the furnace can maintain a target
temperature of 2,000.degree. C. or higher, preferably 2,300.degree.
C. or higher. The furnace may be a generally employed furnace, such
as an Acheson furnace, a resistance furnace, or a high-frequency
furnace. In some cases, there may be employed a method for heating
powder or a molded product formed through compression of the vapor
grown carbon fiber by applying electricity directly thereto.
[0070] Thermal treatment is carried out in a non-oxidative
atmosphere, preferably in an atmosphere of one or more of rare
gasses such as argon, helium, and neon. From the viewpoint of
productivity, thermal treatment is preferably carried out within a
short period of time. When carbon fiber is heated over a long
period of time, the carbon fiber is sintered to form aggregates,
resulting in low production yield. Therefore, after the center of a
molded product of the carbon fiber is heated to a target
temperature, the molded product is not necessarily maintained at
the temperature for more than one hour.
[0071] Each fiber filament of the vapor grown carbon fiber employed
in the present invention preferably has an outer diameter of 2 to
500 nm. In order to cause the carbon fiber to sufficiently exhibit
its characteristics, including tribological characteristics and
electrical conductivity, the carbon fiber must be dispersed
uniformly in the abrasive composite material. The outer diameter of
the carbon fiber filament is more preferably 10 to 300 nm, much
more preferably 20 to 200 nm. The greater the amount of the vapor
grown carbon fiber distributed over the surface of the abrasive
composite material, the more enhanced the tribological
characteristics. When the outer diameter is less than 5 nm,
difficulty is encountered in uniformly dispersing the carbon fiber
in the abrasive composite material, and friction resistance becomes
non-uniform in the composite material, which causes non-uniform
polishing. In contrast, when the outer diameter exceeds 500 nm, a
large amount of the carbon fiber must be added to the abrasive
composite material in order to impart intended electrical
conductivity and thermal conductivity to the composite material. As
a result, the mechanical strength of the abrasive composite
material is lowered, and polishing marks attributed to falling of
the abrasive grains or carbon fiber tend to be formed during the
course of polishing.
[0072] Each fiber filament of the vapor grown carbon fiber employed
in the present invention preferably has an aspect ratio of 5 to
15,000. In order to facilitate uniform dispersion of the carbon
fiber in the abrasive composite material, more preferably, the
aspect ratio of the carbon fiber filament is regulated to 10 to
100.
[0073] When the aspect ratio is less than 5, the carbon fiber loses
its characteristic feature in terms of fibrous form, and the carbon
fiber fails to impart intended electrical conductivity and thermal
conductivity to the abrasive composite material. In contrast, when
the aspect ratio exceeds 15,000, fiber filaments of the carbon
fiber are entangled with one another, and difficulty is encountered
in uniformly dispersing the carbon fiber in the abrasive composite
material. As a result, immediately after the composite material is
molded into a grinding wheel, planarity of the surface of the
grinding wheel is impaired, and friction resistance becomes
non-uniform in the grinding wheel surface, which causes low
planarity of a workpiece.
[0074] The carbon fiber employed in the present invention
preferably has a BET specific surface area of 4 m.sup.2/g or
more.
[0075] When the BET specific surface area is less than 4 m.sup.2/g,
the area of a portion of the carbon fiber that adheres to the
matrix becomes small, and thus the carbon fiber is not sufficiently
captured by the matrix, leading to falling of the carbon fiber from
the abrasive composite material during the course of grinding or
polishing, which causes generation of scratches or polishing
marks.
[0076] The carbon fiber employed in the present invention
preferably has, at a carbon (002) plane, an interlayer distance
(d.sub.002) of 0.345 nm or less as measured by means of X-ray
diffractometry.
[0077] When the (d.sub.002) value exceeds 0.345 nm, thermal
conductivity and tribological characteristics are impaired, which
reduces the ability to radiate heat generated during polishing,
leading to problems, including polishing burn.
[0078] In the carbon fiber employed in the present invention,
preferably, the ratio of the peak height (Id) of the band at 1,341
to 1,349 cm.sup.-1 in a Raman scattering spectrum of the carbon
fiber to the peak height (Ig) of the band at 1,570 to 1,578
cm.sup.-1 in the spectrum; i.e., Id/Ig, is 1.5 or less.
[0079] Id of the Raman spectrum is the height of the peak of a
broad band corresponding to an increase in disturbance of a carbon
structure, and Ig is the height of the peak of a relatively sharp
band corresponding to a complete graphite structure. In general,
the peak intensity ratio is employed as an indicator for the degree
of graphitization of a carbon material. In the case where the peak
intensity ratio is represented by the peak height ratio, when the
degree of graphitization is higher, the peak height ratio becomes
lower.
[0080] When the ratio Id/Ig exceeds 1.5; i.e., crystallinity of a
graphene sheet is low, the carbon fiber exhibits lowered electrical
conductivity and thermal conductivity. Therefore, in some cases,
difficulty is encountered in imparting intended electrical
conductivity and thermal conductivity to the abrasive composite
material.
[0081] The carbon fiber employed in the present invention has a
multi-layer structure, each fiber filament of the carbon fiber
including a hollow space extending along its center axis. Since
each fiber filament of the carbon fiber includes a hollow space,
the carbon fiber exhibits enhanced elasticity, and therefore the
abrasive composite material exhibits enhanced polishing efficiency
and enables suppression of generation of polishing marks. In
addition, since the carbon fiber has a multi-layer structure, the
carbon fiber exhibits high lubricity, and the abrasive composite
material enables suppression of generation of polishing marks. Such
a carbon fiber structure (i.e., a multi-layer structure including a
central hollow space) is specific to carbon fiber produced through
the vapor phase process.
[0082] The carbon fiber employed in the present invention may
contain branched vapor grown carbon fiber. In many cases, branched
vapor grown carbon fiber has a small outer diameter, and each fiber
filament of the carbon fiber has a structure in which a central
hollow portion extends throughout the filament including a branched
portion thereof. In the case where branched vapor grown carbon
fiber is added to the abrasive composite material, even when the
amount of the carbon fiber is small, an electrically conductive or
thermally conductive network can be efficiently formed in the
composite material, as compared with the case where typical vapor
grown carbon fiber is employed. That is, in the case where branched
vapor grown carbon fiber is added to the abrasive composite
material in the same amount as typical vapor grown carbon fiber,
the resultant composite material exhibits further enhanced
electrical conductivity, thermal conductivity, tribological
characteristics, and elasticity.
[0083] In the carbon fiber employed in the present invention,
preferably, boron is contained in crystals constituting the carbon
fiber in an amount of 0.01 to 5 mass %.
[0084] When the carbon fiber contains boron, the crystal layered
structure is developed, and thus electrical conductivity is
enhanced. In addition, by virtue of enhancement of crystallinity
and the effect of boron contained in crystal planes, corrosion
resistance of the carbon fiber is improved, and surface charge
distribution varies. Therefore, the carbon fiber exhibits improved
wettability to the matrix and improved tribological
characteristics. When the boron-containing vapor grown carbon fiber
is added to the abrasive composite material, friction resistance
during the course of polishing can be reduced, and generation of
friction heat can be suppressed. Furthermore, since adhesion of the
carbon fiber to the matrix is improved, falling of the carbon fiber
during the course of polishing can be suppressed.
[0085] The abrasive composite material of the present invention
contains a matrix (e.g., substrate or fabric), abrasive grains, and
carbon fiber, wherein the abrasive grains and carbon powder are
fixed onto the matrix. The abrasive composite material can be
formed into, for example, a grinding wheel through molding of a
mixture of the matrix, which also serves as a binder, the abrasive
grains, and the carbon fiber; a polishing blade by fixing the
abrasive grains and carbon fiber, by use of a binder, onto the
surface of a metallic or ceramic substrate serving as the matrix;
or a polishing pad by fixing the abrasive grains and carbon fiber,
by use of a binder, onto the surface of the matrix formed of
non-woven fabric.
[0086] When the abrasive composite material is formed into a
grinding wheel, the carbon fiber added to the composite material is
preferably 5 to 40 vol. %, more preferably 10 to 30 vol. %. When
the amount of the carbon fiber is 5 vol. % or less, the carbon
fiber fails to impart sufficient tribological characteristics,
elasticity, electrical conductivity, thermal conductivity, and
corrosion resistance to the abrasive composite material, and
therefore, the composite material fails to provide a planar
polished surface. In contrast, when the amount of the carbon fiber
is 40 vol. % or more, adhesion between the carbon fiber and the
matrix is impaired, and the mechanical strength of the abrasive
composite material is lowered. As a result, the carbon fiber or
abrasive grains fall from the abrasive composite material during
the course of polishing, leading to lowering of the quality of the
composite material and a workpiece.
[0087] When the abrasive composite material is formed into a
product by fixing the abrasive grains and carbon fiber, by use of a
binder, onto the surface of a substrate, or a product by fixing the
abrasive grains and carbon fiber, by use of a binder, onto the
surface of the matrix formed of, for example, non-woven fabric, the
amount of the carbon fiber is preferably regulated such that the
ratio by volume of the abrasive grains to the carbon fiber is 1:0.5
to 1:1.
[0088] The above-prepared abrasive composite material of the
present invention, which contains the carbon fiber, exhibits
elasticity, and thus does not apply excess load to an object to be
polished. Therefore, the composite material enables suppression of
generation of polishing marks.
[0089] Planarization of a workpiece requires planarity of a
grinding wheel and uniform distribution of pressure at the surface
at which the grinding wheel is in contact with the workpiece. When
carbon fiber having low bulk density and exhibiting high
elasticity, in particular, vapor grown carbon fiber, is added to
the grinding wheel, the elastic modulus of the grinding wheel is
increased, uniform polishing pressure can be applied to a
workpiece, and the surface of the workpiece can be uniformly
planarized. Even when excess pressure is applied to the workpiece,
by virtue of pressure reduction by deformation of the grinding
wheel, the depth of polishing marks can be decreased, and the
number of polishing marks can be reduced.
[0090] In addition, since the grinding wheel exhibits enhanced
tribological characteristics, electrical conductivity, thermal
conductivity, and corrosion resistance, effects caused by physical
or chemical factors during the course of polishing can be
reduced.
[0091] Particularly when a semiconductor is ground or polished by
use of diamond abrasive grains, oxidation of the diamond abrasive
grains caused by oxygen in air and friction heat can be suppressed,
and the lifetime of the abrasive composite material can be
lengthened.
[0092] Furthermore, during the course of polishing of a
semiconductor wafer or during the course of dressing of a polishing
pad, falling of the abrasive grains of the abrasive composite
material can be suppressed.
[0093] When the abrasive composite material is employed for
polishing of a semiconductor wafer, friction resistance between the
semiconductor wafer and a portion of the composite material other
than the abrasive grains can be reduced, non-uniform polishing of
the semiconductor wafer (i.e., workpiece) can be prevented, the
surface of the wafer can be highly planarized, and polishing burn
can be suppressed through radiation of generated friction heat.
[0094] In addition, when the abrasive composite material is formed
into a grinding wheel, the composite material can impart excellent
mold releasability to the grinding wheel.
[0095] When a workpiece is polished by the grinding wheel, which
comes into surface contact with the workpiece, planarity of the
polishing surface of the grinding wheel affects planarity of the
thus-polished workpiece. Therefore, when a grinding wheel is formed
from the abrasive composite material, a critical point is to remove
the thus-formed grinding wheel from a mold so as to strictly
conform the shape of the mold. In order to improve mold
releasability during forming of the grinding wheel, a mold release
agent, etc. may be employed. However, when the
carbon-fiber-containing abrasive composite material of the present
invention is employed, the resultant grinding wheel exhibits
tribological characteristics, and thus exhibits excellent mold
releasability. Therefore, when the grinding wheel is employed for
grinding or polishing of a workpiece, friction resistance between
the workpiece and a portion of the grinding wheel other than the
abrasive grains can be reduced during the course of grinding or
polishing.
[0096] In addition, the abrasive composite material can impart
electrical conductivity to the grinding wheel. Therefore, the
thickness of the grinding wheel after polishing can be electrically
measured, which enables control operations, including exchange of
the grinding wheel.
[0097] In the case of production of a product through continuous
polishing, in general, the product is planarized while the
polishing amount is controlled by the polishing time, and
therefore, measuring the thickness of a grinding wheel which has
been employed for polishing is important, but the thickness of the
grinding wheel is difficult to measure by means of laser or light.
However, in the case of the carbon-fiber-containing grinding wheel
of the present invention, since the carbon fiber exhibits high
electrical conductivity, electrical conductivity is imparted to the
abrasive grains and the grinding wheel, and the thickness of the
grinding wheel can be controlled by means of electrical resistance.
When the grinding wheel is provided on a substrate exhibiting
electrical conductivity, electrical conduction is established
throughout the resultant product, and thus the position of the
substrate can be detected through electrical conduction detection
means. In addition, when the position of the substrate is
controlled through control means, the same polishing conditions can
be reproduced at any time.
[0098] In order to suppress polishing burn or exhaustion of the
abrasive grains caused by friction heat generated during the course
of polishing, in general, a coolant such as water is supplied to
the grinding wheel during polishing. However, when the carbon fiber
is added to the grinding wheel, further enhanced heat radiation and
cooling effects can be obtained, and thus exhaustion of the
abrasive grains can be suppressed.
[0099] Having been described grinding or polishing of a workpiece
by use of the abrasive composite material of the present invention,
the composite material can be employed in a dresser for a polishing
pad.
[0100] When a semiconductor wafer is polished by use of, for
example, a slurry containing dispersed abrasive grains, a polishing
pad is cleaned between a wafer polishing step and the subsequent
wafer polishing step. When a semiconductor wafer is subjected to,
for example, chemical mechanical polishing, in many cases, a
polishing pad formed of polyurethane foam is employed. When the
polishing pad is observed under an electron microscope after
polishing of the wafer, abrasive grains or chips of the workpiece
are found to be deposited into pores on the pad surface, or the
pores are found to be clogged by, for example, the effect of an
additive (etchant) contained in the slurry. The clogged pores cause
a decrease in the polishing speed, and the deposited abrasive
grains cause an increase in the number of polishing marks.
Therefore, after polishing of the wafer, the polishing pad must be
subjected to dressing, thereby removing excess abrasive grains, and
returning the clogged pores to their original state. Since the pad
surface often exhibits acidity or alkalinity due to the presence of
the etchant contained in the slurry, preferably, the surface of a
dresser to be employed exhibits chemical stability. When carbon
fiber is added to the dresser, the area of a portion of the dresser
that comes into contact with an acid or an alkali can be reduced,
thereby attaining chemical stability, and falling of abrasive
grains can be suppressed.
[0101] Next will be described the method for processing (grinding
or polishing) an electronic part by use of grinding wheel, a
grinding material, or a polishing material, which contains the
abrasive composite material of the present invention.
[0102] A semiconductor integrated circuit will now be described as
an example of an electronic part. In production of a semiconductor
integrated circuit, an insulating layer is formed on the surface of
a silicon wafer which has undergone mirror polishing, and a circuit
pattern formed of a thin film of a metal (e.g., aluminum) is formed
on the insulating layer. In recent years, in order to enhance
performance of an integrated circuit, a multi-layer integrated
circuit including a plurality of insulating layers and circuit
patterns has been widely employed. In formation of a fine circuit
pattern, a circuit pattern is printed, through exposure, onto a
photo-resist film formed on the surface of a conductive thin film,
followed by etching. Therefore, when the surface onto which a
circuit pattern is to be printed does not have planarity, a precise
circuit pattern cannot be formed. In the case of production of such
a multi-layer semiconductor integrated circuit, a silicon wafer
must be subjected to mirror polishing, and an interlayer insulating
film or a metallic thin film for formation of a circuit pattern
must be subjected to high-precision polishing, thereby imparting
planarity thereto.
[0103] The electronic part processing method of the present
invention is applied to grinding (including cutting) or polishing
of a semiconductor material such as a silicon wafer, or to
polishing of an interlayer insulating film or a metallic thin film
to be formed into a circuit pattern. In the electronic part
processing method, when a grinding wheel, grinding material, or
polishing material formed of the abrasive composite material of the
present invention is employed, occurrence of non-uniform polishing
such as dishing or thinning can be prevented, and there can be
obtained a precisely processed surface having neither
micro-scratches nor polishing marks and exhibiting high
planarity.
[0104] Particularly, the grinding wheel of the present invention is
useful for grinding or polishing of silicon, such as
polycrystalline silicon, single-crystal silicon, or amorphous
silicon.
EXAMPLES
[0105] The present invention will next be described in more detail
by way of Examples, which should not be construed as limiting the
invention thereto. In the below-described Examples, characteristics
are measured by means of the following methods.
[0106] (1) BET Specific Surface Area
[0107] BET specific surface area was calculated from a nitrogen
adsorption isothermal curve at the liquid nitrogen temperature by
use of NOVA 1200 (product of Quantachrome) by means of the BET
method and the BJH method. The adsorption amount of nitrogen was
measured at a relative pressure (P/P.sub.0) of 0.01 to 1.0.
[0108] (2) Raman Scattering Spectrum
[0109] Raman scattering spectrum of carbon fiber was obtained under
the following conditions: excitation light: argon (Ar) laser
(wavelength: 514.5 nm), detector: CCD (charge coupled device), slit
distance: 500 .mu.m, exposure time: 60 seconds.
Example 1
[0110] A phenolic resin was mixed with cerium oxide (average
particle size: 0.5 .mu.m) (10 vol. %), and vapor grown carbon fiber
having a multi-layer structure including a central hollow space
(average fiber diameter: 200 nm, aspect ratio: 100, BET specific
surface area: 10 m.sup.2/g, d.sub.002: 0.339 nm, Id/Ig: 0.1) (30
vol. %). The resultant mixture was subjected to pressure molding
for 15 minutes under the following conditions: mold temperature:
160.degree. C., molding pressure: 980.6 kP, to thereby produce a
grinding wheel having a diameter of 50 mm and a thickness of 10 mm.
An insulating-film-coated silicon wafer was polished for three
minutes by use of the grinding wheel, while water was supplied to
the wafer and a load of 49 kP was applied to the grinding wheel.
During the course of polishing, the silicon wafer and the grinding
wheel were rotated in the same direction such that the relative
velocity between them was 10 cm/sec. The polishing speed was
obtained by measuring the thicknesses of the wafer before and after
polishing by use of an optical interference thickness meter. The
surface roughness of the thus-polished wafer was measured by use of
a stylus-type roughness meter. Specimens were observed under an
optical microscope for polishing marks.
[0111] The polishing speed and the surface roughness were found to
be sufficiently practical levels; i.e., 300 nm/min and 2.0 nm,
respectively. Observation of the polished surface under an optical
microscope revealed that no polishing mark was generated on the
wafer surface.
Example 2
[0112] A phenolic resin was mixed with cerium oxide (average
particle size: 0.5 .mu.m) (10 vol. %), and vapor grown carbon fiber
having a multi-layer structure including a central hollow space
(average fiber diameter: 20 nm, aspect ratio: 100, BET specific
surface area: 100 m.sup.2/g, d.sub.002: 0.341 nm, Id/Ig: 0.2) (30
vol. %). The resultant mixture was subjected to pressure molding
for 15 minutes under the following conditions: mold temperature:
160.degree. C., molding pressure: 980.6 kP, to thereby produce a
grinding wheel having a diameter of 50 mm and a thickness of 10 mm.
An insulating-film-coated silicon wafer was polished for three
minutes by use of the grinding wheel, while water was supplied to
the wafer and a load of 49 kP was applied to the grinding wheel.
During the course of polishing, the silicon wafer and the grinding
wheel were rotated in the same direction such that the relative
velocity between them was 10 cm/sec. The polishing speed was
obtained by measuring the thicknesses of the wafer before and after
polishing by use of an optical interference thickness meter. The
surface roughness of the thus-polished wafer was measured by use of
a stylus-type roughness meter. Specimens were observed under an
optical microscope for polishing marks.
[0113] The polishing speed and the surface roughness were found to
be sufficiently practical levels; i.e., 280 nm/min and 1.5 nm,
respectively. Observation of the polished surface under an optical
microscope revealed that no polishing mark was generated on the
wafer surface.
Comparative Example 1
[0114] A phenolic resin was mixed with cerium oxide (average
particle size: 0.5 .mu.m) (10 vol. %), and the resultant mixture
was subjected to pressure molding for 15 minutes under the
following conditions: mold temperature: 160.degree. C., molding
pressure: 980.6 kP, to thereby produce a grinding wheel having a
diameter of 50 mm and a thickness of 10 mm. An
insulating-film-coated silicon wafer was polished for three minutes
by use of the grinding wheel, while water was supplied to the wafer
and a load of 49 kP was applied to the grinding wheel. During the
course of polishing, the silicon wafer and the grinding wheel were
rotated in the same direction such that the relative velocity
between them was 10 cm/sec. The polishing speed was obtained by
measuring the thicknesses of the wafer before and after polishing
by use of an optical interference thickness meter. The surface
roughness of the thus-polished wafer was measured by use of a
stylus-type roughness meter. Specimens were observed under an
optical microscope for polishing marks.
[0115] The polishing speed was found to be a sufficient level;
i.e., 400 nm/min, but the surface roughness was found to increase
to 10.0 nm. Observation of the polished surface under an optical
microscope revealed that polishing marks were generated on the
wafer surface in an amount of about 13 marks/cm.sup.2.
Comparative Example 2
[0116] A phenolic resin was mixed with cerium oxide (average
particle size: 0.5 .mu.m) (10 vol. %), and vapor grown carbon fiber
having a multi-layer structure including a central hollow space
(average fiber diameter: 20 nm, aspect ratio: 2, BET specific
surface area: 130 m.sup.2/g, d.sub.002: 0.341 nm, Id/Ig: 0.2) (30
vol. %). The resultant mixture was subjected to pressure molding
for 15 minutes under the following conditions: mold temperature:
160.degree. C., molding pressure: 980.6 kP, to thereby produce a
grinding wheel having a diameter of 50 mm and a thickness of 10 mm.
An insulating-film-coated silicon wafer was polished for three
minutes by use of the grinding wheel, while water was supplied to
the wafer and a load of 49 kP was applied to the grinding wheel.
During the course of polishing, the silicon wafer and the grinding
wheel were rotated in the same direction such that the relative
velocity between them was 10 cm/sec. The polishing speed was
obtained by measuring the thicknesses of the wafer before and after
polishing by use of an optical interference thickness meter. The
surface roughness of the thus-polished wafer was measured by use of
a stylus-type roughness meter. Specimens were observed under an
optical microscope for polishing marks.
[0117] The polishing speed was found to be a sufficient level;
i.e., 370 nm/min, but the surface roughness was found to increase
to 8.5 nm. Observation of the polished surface under an optical
microscope revealed that polishing marks were generated on the
wafer surface in an amount of about 10 marks/cm.sup.2.
[0118] Table 1 shows the results of polishing performed in the
Examples and Comparative Examples.
[0119] Table 1 shows the percent defective and tribological
characteristics of the grinding wheels of Examples 1 and 2 and
Comparative Example 1, the percent defective being evaluated when
the grinding wheel was released from the mold.
[0120] As used herein, "the percent defective" is defined by the
percentage of grinding wheels which were broken when released from
the mold, or grinding wheels whose surface was partially exfoliated
and deposited onto the mold.
[0121] Tribological characteristics of the grinding wheel were
evaluated by means of the thrust-type friction test. Specifically,
an insulating-film-coated silicon wafer was pressed onto the
grinding wheel for 60 minutes under application of a load of 147
kP, while the grinding wheel was rotated at 20 cm/sec. The amount
of wear of the grinding wheel was measured after the test, and the
thus-measured value was employed as an indicator for evaluation of
tribological characteristics.
1 TABLE 1 Comp. Comp. Ex. 1 Ex. 2 Ex. 1 Ex. 2 Polishing speed
(nm/min) 300 280 400 370 Surface roughness (nm) 2.0 1.5 0.0 8.5
Polishing marks (marks/cm.sup.2) 0 0 13 10 Percent defective (%) 1
1 40 -- Wear amount of grinding wheel (mg) 30 25 560 --
[0122] As is clear from Table 1, in the case of the grinding wheel
of the present invention, a sufficiently practical polishing speed
is attained, surface roughness is small, and high-precision
polishing is attained without generating polishing marks.
[0123] In contrast, in the case of Comparative Example 1, in which
carbon fiber is not employed, polishing speed is high, but surface
roughness is significant, and polishing marks are generated.
Meanwhile, in the case of Comparative Example 2, in which carbon
fiber having a small diameter and a low aspect ratio is employed,
surface roughness is significant, and polishing marks are
generated.
[0124] As is clear from Table 1, when carbon fiber is added to the
grinding wheel, mold releasability of the grinding wheel is
improved. The results of the friction test reveal that addition of
carbon fiber to the grinding wheel improves tribological
characteristics thereof, and exhibits the effect of reducing the
amount of wear of the grinding wheel.
EFFECTS OF THE INVENTION
[0125] Since the abrasive composite material of the present
invention contains carbon fiber, when the composite material is
employed in a grinding material or a polishing material, the
resultant material exhibits tribological characteristics,
elasticity, electrical conductivity, thermal conductivity, and
corrosion resistance, reducing adverse effects attributed to
physical or chemical factors during the course of processing.
Therefore, friction resistance is reduced, non-uniform polishing is
prevented, a polished surface is highly planarized, and
high-precision grinding or polishing can be attained without
generating scratches or polishing marks. In addition, falling of
abrasive grains during the course of grinding or polishing can be
suppressed, generation of polishing marks can be suppressed, burden
on post-treatment of abrasive grains can be reduced, and a grinding
material or polishing material having long lifetime can be
provided.
[0126] Furthermore, when the abrasive composite material of the
present invention is formed into a grinding wheel, the composite
material can impart excellent mold releasability to the grinding
wheel.
[0127] In addition, when the abrasive composite material is formed
into a grinding wheel, electrical conductivity is imparted to the
grinding wheel. Therefore, the thickness of the grinding wheel
after polishing can be electrically measured, which enables control
operations, including exchange of the grinding wheel.
[0128] Moreover, enhanced heat radiation and cooling effects can be
obtained, and thus exhaustion of abrasive grains can be
suppressed.
[0129] When the electronic part processing method of the present
invention is employed, a semiconductor substrate, or an interlayer
insulating film or circuit pattern constituting an electronic
device can be processed at high precision and high efficiency.
Particularly, the processing method exhibits its effects when
employed for grinding or polishing of silicon, such as
polycrystalline silicon, single-crystal silicon, or amorphous
silicon.
[0130] The abrasive composite material of the present invention can
be employed in a dresser for a polishing pad.
* * * * *