JP2002057130A - Polishing pad for cmp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing pad for CMP at low cost which has favorable frictional property and excellent durability and does not cause a flaw or scratch on a machined surface of a semiconductor wafer. SOLUTION: This polishing pad for CMP has a base material and a polishing layer provided on the base material. The polishing layer has a three-dimensional structure constituted by a plurality of regularly arranged three-dimensional elements in a predetermined shape. The polishing layer is made of a polishing composite containing advanced alumina abrasive grains prepared by the CVD method and a binder as components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing pad whose polishing layer has a three-dimensional structure, and more particularly to a polishing pad used for planarizing a semiconductor wafer by a chemical and mechanical polishing (CMP) process. The present invention relates to a polishing pad in which a polishing layer has a three-dimensional structure.

[0002]

2. Description of the Related Art The CMP process has been recognized as a standard process for flattening a semiconductor wafer with high integration of devices and multilayer wiring. The basic structure of the CMP system consists of two units, processing and cleaning. In general, the processing unit is basically composed of a head unit that applies rotational pressure while maintaining a semiconductor wafer and a driving mechanism thereof, a platen to which a pad is attached in a form facing the head unit, and a driving mechanism thereof. In addition, a conditioning (dressing) mechanism for the polishing pad, a cleaning mechanism for cleaning the wafer chuck surface and the like, a working liquid supply mechanism, and the like are provided.

[0003] Since the structure and characteristics of the polishing pad greatly affect the polishing characteristics by processing, further improvement is desired as a key technology for supporting the CMP process. The structure of the polishing pad has a micro-side and a macro-side, each of which affects the polishing characteristics. The microscopic structure refers to the type of abrasive grains and binder, the foamed state, the surface state, and the like. The macro structure is a surface shape such as a hole, a groove, or a projection.

Japanese Patent Publication No. 11-512874 describes a polishing pad for a semiconductor wafer whose polishing layer has a regular three-dimensional structure. This polishing pad can be used for a CMP process. If the polishing layer has a three-dimensional structure, loading is unlikely to occur, so that this polishing pad has stable polishing and excellent durability.

However, a polishing pad in which a polishing layer has a three-dimensional structure has a characteristic that the performance of abrasive grains easily affects the polishing characteristics. Therefore, when general-purpose α-alumina abrasive grains are used, there is a problem that it is difficult to sufficiently improve the finish of the surface to be cut. Particularly, in the CMP process, the surface roughness of the semiconductor wafer is 1-2 nmRy after securing high flatness.
(Maximum height, JIS B 0601), OSF (Oxidat
It is required to be ion-induced Stacking Fault free, micro scratch free, and haze free.

However, when α-alumina abrasive grains obtained by a conventional general manufacturing method are used for a three-dimensionally structured polishing material, the frictional force at the time of polishing is high, and defects and scratches are liable to be generated on the work surface. On the other hand, when expensive abrasive grains such as diamond are used, the production cost of the polishing pad increases.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. It is an object of the present invention to provide a semiconductor wafer having good friction characteristics and excellent durability, and defects and scratches on a surface to be cut of a semiconductor wafer. It is an object of the present invention to provide a low-cost CMP polishing pad.

[0008]

SUMMARY OF THE INVENTION The present invention has a three-dimensional structure including a base material and a polishing layer provided on the base material, wherein the polishing layer includes a plurality of three-dimensional elements of a predetermined shape regularly arranged. The present invention provides a polishing pad for CMP having a structure, wherein the polishing layer comprises a polishing composite containing advanced alumina abrasive grains and a binder produced as components by a CVD method. Is achieved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical example of a polishing layer is shown in FIGS.
Examples are shown in 3 and 4.

[0010] Preferred polishing layers may be regularly shaped (as defined in the above disclosure) or irregularly shaped, with regularly shaped polishing layers being preferred.

[0011] The shape of the individual solid elements may have any of a variety of geometric solids. In general, the base surface of the three-dimensional element that contacts the substrate has a larger area than the terminal part. The shape of the three-dimensional element can be cube, cylinder, prism, truncated prism,
Choose from a number of geometric solids such as stripes, rectangles, pyramids, truncated pyramids, tetrahedrons, truncated tetrahedra, cones, truncated cones, hemispheres, truncated hemispheres, cross-sections or columnar sections with crossed ends can do.

The pyramid of three-dimensional elements may have four, five or six faces. The three-dimensional elements may have a mixture of different shapes. The three-dimensional elements may be arranged in rows, spirals, spirals or lattices, or may be arranged randomly.

The side surface forming the three-dimensional element may be perpendicular to the substrate, inclined with respect to the substrate, or inclined with decreasing width toward the end. If the sides are inclined, it is easier to remove the three-dimensional element from the mold cavity of the mold, ie the production tool. The angle of inclination may range from about 1 to 75 degrees, preferably about 2 to 50 degrees, more preferably about 3 to 35 degrees, and most preferably about 5 to 15 degrees.

When the angle is smaller, the contact area is apparently constant when the three-dimensional element is worn. Therefore, a smaller angle is preferable. Thus, in general, the angle of inclination is a compromise between an angle large enough to facilitate removal from the mold or production tool and an angle small enough to form a uniform cross-sectional area. Although it is possible to use a three-dimensional element having a larger cross section at the end than at the base,
Its manufacture requires more than simple molding methods.

Although the heights of the three-dimensional elements are preferably the same, some of the three-dimensional structures of the polishing layer may have different heights. The height of the three-dimensional element is based on the surface of the base material,
Generally less than about 2000 micrometers, more preferably in the range of about 25-200 micrometers.

Although the base surfaces of the three-dimensional elements may be in contact with each other,
Alternatively, the base surfaces of adjacent three-dimensional elements may be separated from each other by a predetermined distance. In some embodiments, the physical contact between adjacent three-dimensional elements does not exceed 33% of the vertical height dimension of each touching three-dimensional element. More preferably, the amount of physical contact between adjacent three-dimensional elements is in the range of 1 to 25% of the vertical height of each three-dimensional element in contact.

The definition of “contact” includes an arrangement in which adjacent three-dimensional elements share a common three-dimensional element depression, and a bridge-like structure in which the facing side walls of the three-dimensional elements are connected and extended. Preferably, the depression structure has a height not exceeding 33% of the vertical height dimension of each adjacent solid element. The depressions between the solids are formed from the same slurry used to form the solids. The three-dimensional elements are “adjacent” in the sense that no intervening three-dimensional elements are arranged on a straight virtual line drawn between the centers of the three-dimensional elements. Preferably, at least some of the three-dimensional elements are spaced apart from each other so as to provide a recessed portion between the raised portions of the three-dimensional element.

The unidirectional spacing of the three-dimensional elements may range from about one three-dimensional element per cm to about 100 three-dimensional elements per cm. The spacing of the three-dimensional elements in one direction may vary such that the density of the three-dimensional elements is greater at one location than at another location. For example, the density may be highest at the center of the polishing pad. The area density of three-dimensional elements is about 1-10,
000 three-dimensional elements / cm ² range.

Arrangements are also possible in which the surface of the substrate is exposed, ie the abrasive coating does not cover the entire surface area of the substrate. This type of sequence is described in U.S. Patent No. 5,014,468 (Ravipati et al.).

The three-dimensional elements are preferably arranged on the base material in a predetermined pattern or on the base material at a predetermined position. For example, in an abrasive article manufactured by providing a slurry between a substrate and a manufacturing tool having a mold cavity,
The predetermined pattern of the three-dimensional element corresponds to the pattern of the mold hole of the manufacturing tool. Therefore, the pattern is reproduced for each article.

In one embodiment of the predetermined pattern, the three-dimensional elements are present in an array. This means that the three-dimensional elements exist in a regular arrangement such as a row and column arrangement or a row and column staggered arrangement. If desired, one row of the three-dimensional element can be placed directly before the second row of the three-dimensional element. Preferably, one row of the three-dimensional element may be staggered with the second row of the three-dimensional element.

In another embodiment, the three-dimensional elements may be arranged in a "random" array or pattern. this is,
It means that the three-dimensional elements are not in the regular arrangement of rows and columns as described above. For example, the three-dimensional element is disclosed in PCT95 / 07 published on March 23, 1995.
No. 797 (Hoopman et al.) And 1
PCT9, a public information publication released on August 24, 995
5/22436 (Hoopman et al.)
May be arranged in a manner as described in the above. However, this "random" arrangement is a predetermined pattern in that the locations of the three-dimensional elements on the abrasive article are predetermined and correspond to the locations of the mold holes in the manufacturing tool used to manufacture the abrasive article. .

The three-dimensionally structured abrasive articles may have different abrasive coating compositions. For example, the center of the polishing disk may contain a different abrasive coating (eg, soft, firm, or somewhat edible) than the outer region of the polishing disk.

The abrasive article 10 shown in FIG. 1 has a pyramid-shaped three-dimensional element 11 fixed or adhered to a substrate 12.
Depressions or valleys 13 exist between adjacent three-dimensional elements.
Differently from the first row, there is also a pyramid-like three-dimensional element in the second row. The outermost point or end of the pyramidal 3D element contacts the wafer surface during the process.

The abrasive article 20 of FIG. 2 has an irregularly shaped pyramid-shaped solid element. In this particular example, the three-dimensional element has a pyramidal shape. The boundaries forming the pyramid are irregularly shaped. Imperfect shape can be the result of the slurry flowing and distorting the initial shape before the binder precursor hardens or solidifies significantly. Irregular shapes are characterized by non-straight, unclean, non-reproducible, inaccurate or non-perfect plane or shape boundaries.

The abrasive article 30 of FIG. 3 has a truncated pyramid-shaped three-dimensional element 31.

The abrasive article 40 of FIG.
And a three-dimensional element having a shape 42 of “x”. The three-dimensional element is
They are arranged in a horizontal pattern. The various side-by-side comma three-dimensional elements are staggered from each other and do not directly line up with adjacent side-by-side three-dimensional elements. In addition, the rows of three-dimensional elements are separated by spaces or valleys. The valleys or spaces may contain only a small amount (as measured by height) of cubic elements or may not contain cubic elements.

The three-dimensional elements of another arrangement or configuration are similar, except that each alternating row includes either a three-dimensional element having a "cross" shape or a three-dimensional element having an "x" shape.
It is the same as FIG. In this arrangement, the odd-numbered three-dimensional elements are staggered with the even-numbered three-dimensional elements. With the cross-shaped or "x" -shaped solid elements in the above arrangement, the length of one line forming either the cross or the x-shaped is about 75
At 0 micrometers, the width of one line forming either a cross or an x-shape is preferably about 50 micrometers.

FIG. 5 is a perspective view of a polishing surface of a polishing pad for CMP which is an example of the present invention. The three-dimensional structure of the polishing layer is displayed. The three-dimensional structure of the polishing layer is composed of a plurality of three-dimensional elements. The shape of the three-dimensional element is cylindrical, and a plurality of cylindrical shapes are regularly arranged.

FIG. 6 is a plan view of a polishing surface of the polishing pad for CMP. It shows an example of an arrangement mode of a three-dimensional element. Rows A, B,... Are formed by arranging a plurality of three-dimensional elements in the horizontal direction at the same interval, and these rows are arranged in the vertical direction so that the three-dimensional elements are staggered.

In FIG. 6, the symbol d indicates the diameter of a cylinder which is a three-dimensional element. d is, for example, 10 to 5000 μm, preferably 50 to 500 μm, and more preferably 100 to 300 μm.
μm. Symbol e indicates a distance between adjacent three-dimensional elements in the same row. The symbol f indicates the distance between adjacent three-dimensional elements in an adjacent row. e and f may be the same size or different sizes, for example, 10 to 10,000 μm, preferably 50 to 10,000 μm.
It is 1000 μm, more preferably 100-300 μm. Generally, e and f have the same dimensions.

FIG. 7 shows the polishing pad for CMP shown in FIG.
It is sectional drawing cut | disconnected by X 'plane. In FIG. 7, a polishing pad 1 has a substrate 2 and a polishing layer 3 provided on the surface of the substrate. The polishing layer 3 has a three-dimensional structure.

The substrate needs to have a uniform thickness. If the thickness of the base material is not sufficiently uniform, variations may occur in the work surface and the wafer thickness of the semiconductor wafer. Any of a variety of substrate materials, including flexible substrates and relatively rigid substrates, are suitable for the purposes of the present invention.

Preferred materials for the substrate include polymer films, papers, fabrics, metal films, vulcan fibers, non-woven substrates, combinations thereof, and treated products thereof. One preferred type of substrate is a polymer film. Examples of such films include polyester and copolyester films, microporous polyester films, polyimide films, polyamide films, polyvinyl alcohol films, polypropylene films, polyethylene films, and the like. The thickness of the polymer film substrate is generally about 20-1000 μm, preferably 50-500 μm, more preferably 60-2 μm.
It is in the range of 00 μm. For example, the substrate may be a polyethylene terephthalate (PET) film.

The adhesion between the polymer film substrate and the abrasive coating must be good. In many cases, the coated side of the polymer film substrate is primed to improve adhesion. For example, the polymer film may be primed with a material such as polyethylene acrylic acid to promote adhesion of the abrasive composite to the substrate.

The polishing layer 3 is made of a polishing composite including a binder matrix and abrasive grains 4 dispersed therein.

The abrasive composite is formed from a slurry containing a plurality of abrasive grains dispersed in an uncured or ungelled binder. Upon curing or gelling, the abrasive composite is solidified, ie, fixed in a predetermined shape and a predetermined structure.

A type of abrasive suitable for the present invention is α-alumina particles. α-alumina particles are general-purpose oxide materials used in a wide range of applications from refined aluminum raw materials to fine ceramic raw materials.

Conventionally, α-alumina particles for industrial use have been produced by a Bayer method, a method of thermally decomposing fine aluminum hydroxide or alum, an electrofusion method, or the like. In these methods, an alumina raw material is fired or melted at a high temperature to form an alumina block, and then the particle size is adjusted by pulverization, purification, and sieving. Therefore, such α-
Alumina particles are polycrystals having a non-uniform shape, contain many agglomerated particles, have a wide particle size distribution, and have problems such as low alumina purity depending on applications.

The α-alumina particles used in the present invention are preferably advanced alumina abrasive grains. The advanced alumina particles refer to α-alumina particles produced by an in situ chemical vapor deposition method (hereinafter, referred to as a CVD method). The advanced alumina particles are more excellent in particle size distribution and the uniformity of the crystal system of the alumina particles than those baked and pulverized as described above.

The advanced alumina abrasive grains are homogeneous single crystal particles composed of crystal-grown particles, and have a nearly spherical shape. Further, since the crystal growth size can be controlled, the particle size distribution becomes sharp. For the features and applications of advanced alumina abrasive grains, see Masahide Mohri (Ma
sahide Mohri), Shin-ichiro Tanaka (Shin-ichiro Tanaka),
Yoshio Uchida, "Development of Advanced Alumina", Functional Materials, December 1996, Vol. 16, No. 12, No. 1
It is described on pages 8 to 27.

Particularly preferred advanced alumina abrasive grains for use in the present invention are described in JP-A-6-191836. That is, the maximum particle diameter parallel to the hexagonal lattice plane of α-alumina, which is homogeneous and has no crystal seeds therein, has a polyhedral shape of eight or more faces, and is a hexagonal close-packed lattice, is D, and is perpendicular to the hexagonal lattice plane. when the particle diameter is H such, D / H ratio is 0.5 to 3.0 α- alumina made of single-crystal particles of sodium content in terms of Na ₂ O 0.0
Less than 5% by weight and alumina purity of 99.90% by weight
The powdered α-alumina described above.

The size of the abrasive grains varies depending on the type of the semiconductor wafer to be polished and the required finish of the work surface.
For example, the average particle size is 0.1 to 50 μm, preferably 0.3 to 5 μm, and more preferably 0.4 to 2 μm. Such advanced alumina abrasive grains are commercially available from Sumitomo Chemical Co., Ltd. under the trade name "Sumicorundum".

When advanced alumina particles are used as abrasive grains of a polishing pad for CMP in which the polishing layer has a three-dimensional structure, the frictional force during polishing is reduced in the CMP process to stabilize polishing, and defects and scratches on the surface to be processed are reduced. Is less likely to occur.

The binder forms a polishing layer by hardening or gelling. Examples of preferred binders for the present invention include:
Phenolic resin, resol-phenol resin, aminoplast resin, urethane resin, epoxy resin, acrylic resin, polyester resin, vinyl resin, melamine resin, acrylated isocyanurate resin, urea-formaldehyde resin, isocyanurate resin, acrylated urethane resin, Includes acrylated epoxy resins and mixtures thereof. The binder may be a thermoplastic resin.

Particularly preferred are radiation-curable binders. Irradiation curable binders are any binders that can be at least partially cured or at least partially polymerized by irradiation energy. Depending on the binder used, energy sources such as heat, infrared, electron beam, ultraviolet radiation or visible light radiation are used.

Typically, these binders are polymerized by a free radical mechanism. Preferably, these include ethylenically unsaturated compounds such as ethylenically unsaturated monomers and oligomers, acrylated urethanes, acrylated epoxies, aminoplast derivatives having α, β-unsaturated carbonyl groups, ethylenically unsaturated groups. Isocyanurate derivatives, isocyanates having an ethylenically unsaturated group, and mixtures thereof.

The ethylenically unsaturated compound may be monofunctional, difunctional, trifunctional, tetrafunctional or even higher functional, and may include both acrylic and methacrylic monomers. Ethylenically unsaturated compounds include both monomeric and polymeric compounds containing carbon, hydrogen and oxygen atoms, and optionally, nitrogen and halogen atoms.

Oxygen or nitrogen atoms, or both, are generally contained in ether, ester, urethane, amide and urea groups. Suitable ethylenically unsaturated compounds preferably have a molecular weight of less than about 4000, and preferably have a compound having an aliphatic monohydroxy group or an aliphatic polyhydroxy group, and acrylic acid, methacrylic acid, itaconic acid, crotonic acid, Isocrotonic acid,
Esters produced from the reaction with unsaturated carboxylic acids such as maleic acid.

Representative examples of ethylenically unsaturated monomers include ethyl methacrylate, styrene divinylbenzene, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, vinyl toluene, Ethylene glycol diacrylate, polyethylene glycol diacrylate, ethylene glycol dimethacrylate, hexanediol diacrylate,
Examples include triethylene glycol diacrylate, trimethylolpropane triacrylate, glycerol triacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate and pentaerythritol tetramethacrylate.

Other ethylenically unsaturated materials include monoallyl, polyallyl and polymethallyl esters, such as diallyl phthalate, diallyl adipate and N, N-diallyl adipamide, and carboxylic acid amides. Still other nitrogen-containing compounds include tris (2-acryl-oxyethyl) isocyanurate, 1,3,5-
Tri (2-methacryloxyethyl) -s-triazine, acrylamide, methacrylamide, N-methyl-
Acrylamide, N, N-dimethylacrylamide, N
-Vinyl-pyrrolidone and N-vinyl-piperidone.

Examples of suitable monofunctional acrylates and methacrylates that can be used in combination with di- or trifunctional acrylate and methacrylate monomers or with phenolic or epoxy resins include:
Lauryl acrylate, octyl acrylate, 2-
Examples include (2-ethoxyethoxy) ethyl acrylate, tetrahydrofurfuryl methacrylate, cyclohexyl acrylate, stearyl acrylate, 2-phenoxyethyl acrylate, isooctyl acrylate, isobornyl acrylate, isodecyl acrylate, polyethylene glycol monoacrylate and polypropylene glycol monoacrylate. Can be

If the binder is cured by UV irradiation, a photoinitiator is required to initiate free radical polymerization. Examples of preferred photoinitiators for this purpose include organic peroxides, azo compounds, quinones, benzophenones, nitroso compounds, acryl halides, hydrazones,
Includes mercapto compounds, pyrylium compounds, triacrylimidazoles, bisimidazoles, chloroalkyl triazines, benzoin ethers, benzyl ketals, thioxanthone and acetophenone derivatives. The preferred photoinitiator is 2,2-dimethoxy-1,2-diphenyl-1-ethanone.

If the binder is cured with visible radiation, the photoinitiator is required to initiate free radical polymerization. Examples of preferred photoinitiators for this purpose are described in U.S. Pat. No. 4,735,632, incorporated herein by reference.
Column 3, line 25 to column 4, line 10, column 5 lines 1-7
Line, column 6, lines 1-35.

The concentration of the abrasive grains contained in the polishing composite is 10 to 90% by weight, preferably 40 to 80% by weight, more preferably 60 to 75% by weight. This ratio varies depending on the size of the abrasive grains, the type of the binder used, the required finish of the work surface, and the like.

The abrasive composite may include materials other than the abrasive and the binder. Conventional additives such as, for example, coupling agents, wetting agents, dyes, pigments, plasticizers, fillers, release agents, polishing aids and mixtures thereof.

The abrasive composite can include a coupling agent. By adding a coupling agent,
The coating viscosity of the slurry used to form the abrasive composite can be significantly reduced. Examples of such coupling agents preferred for the present invention include organosilanes, zircoaluminates and titanates. The amount of coupling agent is generally less than 5% by weight of the binder, preferably 1%.
% By weight.

The polishing layer 3 has a three-dimensional structure including a plurality of three-dimensional elements 5 of a constant shape arranged regularly. The three-dimensional element 5 has a cylindrical shape. The height h of the cylinder is 10 to 500 μ
m, preferably 20-200 μm, more preferably 30
６５65 μm.

The abrasive grains 4 do not protrude beyond the surface of the three-dimensional element shape. That is, the three-dimensional element 5 is configured by a smooth plane. For example, the surface constituting the three-dimensional element 5 has a surface roughness Ry of 2 μm or less, preferably 1 μm or less.

FIG. 8 is a plan view of a polishing surface of a polishing pad for CMP according to another example of the present invention. In this example, the three-dimensional element is a tetrahedron with ridges connected at points at the tops.
In that case, the apex angle α between the two ridge lines is usually 30 to 1
It is 50 °, preferably 45-140 °. The three-dimensional element may have a pyramid shape. In that case, the apex angle between the two ridge lines is usually 30 to 150 °, preferably 45 °.
゜ 140 °. The height of this three-dimensional element is, for example,
It is 2 to 300 μm, preferably 5 to 150 μm.

In FIG. 8, the symbol o indicates the base length of the three-dimensional element. The symbol p indicates the distance between the tops of the three-dimensional elements. o is, for example, 5 to 1000 μm, preferably 10 to 500 μm. p is, for example, 5 to 1000 μm, preferably 10 to 500 μm.

The top of this three-dimensional element may be cut to a predetermined height to form a tetrahedron with a flat top. In that case, the height of the three-dimensional element is 5 to 95%, preferably 10 to 90% of the height of the three-dimensional element before the top is cut.

FIG. 9 is a plan view of a polishing surface of a polishing pad for CMP according to another example of the present invention. In this example, the three-dimensional element has a pyramid shape in which the top is cut at a predetermined height and the upper surface is flat. The height of this three-dimensional element is the same as that of the tetrahedron shown in FIG.

In FIG. 9, the symbol o indicates the base length of the three-dimensional element. The symbol u indicates the distance between the bases of the three-dimensional element. Symbol y indicates the length of one side of the upper surface. o is, for example, 5 to 2000 μ
m, preferably 10 to 1000 μm. u is, for example, 0 to 1000 μm, preferably 2 to 500 μm. y is, for example, 0.5 to 1800 μm, preferably 1 to 900 μm.

FIG. 10 is a plan view of a polishing surface of a polishing pad for CMP according to another example of the present invention. In this example, the three-dimensional element has a prism shape in which a triangular prism is oriented in a horizontal direction, and an end of the prism-shaped three-dimensional element is cut at an acute angle from below to form a ridge-shaped ridge having slopes on all sides. Prism,
The vertex angle of a triangle cut in a plane perpendicular to the length direction is usually 30 to
The angle is set to 150 °, preferably 45 to 140 °. The height of the three-dimensional element is, for example, 2 to 600 μm, and preferably 4 to 300 μm.

Incidentally, the length of the prismatic three-dimensional element may be extended over substantially the entire area of the polishing pad. Or, FIG.
May be interrupted at the appropriate length. The ends may or may not be aligned. The top may be cut to form a prism having a flat top surface. In that case, the height of the three-dimensional element is 5 to 95%, preferably 10 to 90% of the height of the three-dimensional element before the top is cut.

In FIG. 10, reference numeral 1 denotes the length of the long base of the three-dimensional element. The symbol v indicates the distance of the three-dimensional element cut off at an acute angle. The symbol x indicates the distance between the short bases of the three-dimensional element.
The symbol w indicates the length of the short base of the three-dimensional element (the width of the three-dimensional element). The symbol p indicates the distance between the tops of the three-dimensional elements. The symbol u indicates the distance between the long bases of the three-dimensional element. l is, for example, 5 to 10
000 μm, preferably 10 to 5000 μm.
v is, for example, 0 to 2000 μm, preferably 1 to 10 μm.
00 μm. x is, for example, 0 to 2000 μm;
Preferably it is 0 to 1000 μm. w is, for example,
It is 2 to 2000 μm, preferably 4 to 1000 μm. p is, for example, 2 to 4000 μm, preferably 4 to 4000 μm.
2000 μm. u is, for example, 0 to 2000 μ
m, preferably 0 to 1000 μm.

The polishing pad for CMP of the present invention is preferably manufactured by the method described below.

First, an abrasive coating liquid containing abrasive grains and a binder is prepared. The abrasive coating liquid used here contains a sufficient amount of a binder, abrasive grains, and additives such as a photoinitiator, if necessary, to constitute a polishing composite, and is used to impart fluidity to the mixture. It is a composition that may further contain a sufficient amount of a volatile solvent.

Next, a mold sheet having a plurality of recesses regularly arranged is prepared. The shape of the concave portion may be a shape obtained by inverting the three-dimensional element to be formed. As a material of the mold sheet, for example, a metal such as nickel, a plastic such as polypropylene, or the like may be used. For example,
Since a thermoplastic resin such as polypropylene can be embossed on a metal tool at its melting temperature, a recess having a predetermined shape can be easily formed, which is preferable. When the binder is a radiation curable resin, it is preferable to use a material that transmits ultraviolet light or visible light.

A mold sheet is filled with an abrasive coating solution. The filling can be performed by applying the abrasive coating liquid to the mold sheet by a coating device such as a roll coater.

The substrate is placed on the mold sheet, and the abrasive coating solution is adhered to the substrate. The bonding is performed, for example, by a method of pressing and laminating with a roll.

The binder is cured. As used herein, the term "curing" means polymerizing to a solid state. After curing, the specific shape of the polishing layer does not change.

The binder is cured by heat, infrared radiation or other radiation energies such as electron beam radiation, ultraviolet radiation or visible light radiation. The amount of irradiation energy applied depends on the type of binder used and the irradiation energy source. In general, those skilled in the art can appropriately determine the application amount of the irradiation energy. The time required for curing will vary depending on the thickness, density, temperature and composition characteristics of the binder.

For example, ultraviolet light (UV)
May be applied to cure the binder.

By removing the mold sheet, a polishing pad comprising a base material and a polishing layer having a three-dimensional structure is obtained. After removing the mold sheet, the binder may be cured. The structure of the obtained polishing pad may be changed by an ordinary method such as bonding to a flat hard support.

[0077]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. Unless otherwise specified, “parts” in the examples are on a weight basis.

Example An abrasive coating liquid was prepared by blending the components shown in Table 1.

[0079]

[Table 1]

A polypropylene mold sheet having a concave portion having a shape obtained by inverting the cylindrical three-dimensional element shown in FIGS. 5 to 7 was prepared. The distance between adjacent three-dimensional elements was adjusted so that the total contact area with the semiconductor wafer was 18%. Table 2 shows the dimensions.

[0081]

[Table 2]

An abrasive coating solution was applied to a polypropylene mold sheet by a roll coater. Thickness 1 on this
A transparent PET film having a thickness of 00 μm was laminated, and laminated by applying pressure with a roll. The binder was cured by irradiation with ultraviolet rays.

The mold sheet was removed and cooled to room temperature to obtain a polishing pad. In this polishing pad, the polishing layer has the three-dimensional structure shown in FIG. 5, and the size is 1.27 cm wide × 1 length.
It is a 0 cm tape. The polishing performance of this polishing pad was tested.

[0084] As a test method of friction of the polishing pad to the frictional force diagram 11 schematically represents. A glass tube having a diameter of 10 mm was used as a workpiece. A glass tube 11 as a work was mounted on a shaft of a motor (not shown). The polishing pad 12 was hung on the glass tube 11 with the polishing surface inside, one end was fixed to the strain gauge 13, and a 200 g weight 14 was attached to the other end.

The glass tube was rotated in the direction of the arrow by starting the motor. The rotation speed was 240 rpm. The friction force (g) displayed on the strain gauge 13 was read and recorded over time. The results are shown in the graph of FIG.

The polishing pad of the present invention had a low frictional force, did not show a tendency to increase even after the polishing time had elapsed, and had good friction characteristics.

Finish of Work Surface The finish of the work surface of the glass tube polished for 4 minutes by the above method was measured with an optical microscope (magnification: 50 times).

The work surface polished with the polishing pad of the present invention was free from defects and scratches and had high flatness.

Comparative Example A wet process alumina ("TIZOX8109" manufactured by Transelco, particle size: about 0.15 μm) instead of the CVD process alumina abrasive grains
A polishing pad was prepared in the same manner as in Example 1 except that the polishing pad was used, and its polishing performance was tested. The results are shown in the graph of FIG.

The polishing pad of the comparative example had a high frictional force, and the frictional force tended to increase after the polishing time had elapsed, and the friction characteristics were poor. The work surface polished with the polishing pad of the comparative example had defects and scratches, and had low flatness.

[0091]

The present invention provides a low-cost polishing pad for CMP which has good friction characteristics and excellent durability and does not cause defects or scratches on the work surface of a semiconductor wafer.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of the structure of a polishing layer of the present invention.

FIG. 2 is a cross-sectional view showing an example of the structure of the polishing layer of the present invention.

FIG. 3 is a cross-sectional view showing an example of the structure of the polishing layer of the present invention.

FIG. 4 is a plan view showing an example of a polishing layer of the present invention.

FIG. 5 is an enlarged photograph of a polishing surface of a polishing pad for CMP which is an example of the present invention.

FIG. 6 is a plan view of a polishing surface of a polishing pad for CMP which is an example of the present invention.

FIG. 7 is a cross-sectional view of a polishing pad for CMP which is an example of the present invention.

FIG. 8 is a plan view of a polishing surface of a polishing pad for CMP according to another example of the present invention.

FIG. 9 is a plan view of a polishing surface of a polishing pad for CMP according to another example of the present invention.

FIG. 10 is a plan view of a polishing surface of a polishing pad for CMP according to another example of the present invention.

FIG. 11 is a schematic view illustrating a method for testing a frictional force of a polishing pad.

FIG. 12 is a graph plotting a change in frictional force generated in a polishing process over time.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Polishing pad, 2 ... Substrate, 3 ... Polishing layer, 4 ... Abrasive grains, 5 ... Three-dimensional element.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B24D 3/28 B24D 3/28 C08J 5/14 CEZ C08J 5/14 CEZ C08K 7/00 C08K 7/00 C08L 101/00 C08L 101/00 C09K 3/14 550 C09K 3/14 550D 550K (72) Inventor Kengo Imamura 3-8-8 Minamihashimoto, Sagamihara City, Kanagawa Prefecture F-term in Sumitomo 3M Limited (Reference) 3C058 AA09 CB02 CB05 CB10 DA12 DA17 3C063 AA02 AB07 BA24 BB03 BB07 BC03 BG08 BH07 CC17 CC23 EE10 FF08 FF23 4F071 AA31 AA41 AA42 AA53 AA69 AB18 AD02 AD06 AD07 DA18 DA19 4J002 BG021 BQ001 CC031 CC041 CC151 CC161 CC181 CD001 CF001

Claims (5)

[Claims] 1. A polishing apparatus comprising: a base material; and a polishing layer provided on the base material, wherein the polishing layer has a three-dimensional structure including a plurality of three-dimensional elements of a predetermined shape arranged regularly. A polishing pad for CMP comprising a polishing composite containing advanced alumina abrasive grains and a binder produced by a CVD method as constituent components. 2. The shape of the three-dimensional element may be a cylinder, a cone, a tetrahedron, a pyramid, a tetrahedron or a pyramid having a flat top, a prism, a prism having a flat top, and a stripe. The polishing pad for CMP according to claim 1, which is selected from the group consisting of: 3. The polishing pad for CMP according to claim 1, wherein the average particle diameter of the advanced alumina abrasive grains is 0.01 to 20 μm. 4. The polishing pad for CMP according to claim 1, wherein the concentration of abrasive grains contained in the polishing composite is 10 to 90% by weight. 5. The binder according to claim 1, wherein the binder is a phenol resin, an aminoplast resin, a urethane resin, an epoxy resin, an acrylic resin, an acrylated isocyanurate resin, a urea-formaldehyde resin, an isocyanurate resin, an acrylated urethane resin, or an acrylated epoxy resin. The polishing pad according to claim 1, wherein the polishing pad is selected from the group consisting of, glue, and a mixture thereof.