JP2002151448A - Cmp pad for cerium oxide polishing agent and method of polishing wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CMP pad for a cerium oxide polishing agent with which a substrate such as a silicon oxide film or the like can be polished efficiently at a high speed and can readily control its process in a CMP technique for planarizing an interlayer dielectric, and a BPSG film and a shallow trench isolation insulating film, and to provide a method of polishing a wafer by using the same. SOLUTION: This CMP pad for a cerium oxide polishing agent is used to polish a thin film formed on a substrate chemically and mechanically by using a cerium oxide polishing agent and has fine projections and depressions on the surface. The mean surface roughness Ra along the center line of the pad surface is defined by the ratio to the D99% grain size of polishing agent particles measured by a laser scattering grain size distribution measuring instrument.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of polishing a CMP pad and a substrate suitably used in a semiconductor device manufacturing technique, and more particularly to a method of polishing an interlayer insulating film and a BPSG (silicon dioxide film doped with boron and phosphorus) film. Flattening process, shallow
The present invention relates to a cerium oxide abrasive CMP pad used in a trench isolation forming step and the like, and a substrate polishing method using the CMP pad.

[0002]

2. Description of the Related Art At present, ultra-large-scale integrated circuits tend to increase the packing density, and various microfabrication techniques have been studied and developed. Already, design rules are on the order of sub-half microns. One of the technologies that have been developed to satisfy such strict requirements for miniaturization is a CMP (Chemical Mechanical Polishing) technology. This technology completely flattens the layer to be exposed in the semiconductor device manufacturing process, reducing the burden of the exposure technology,
Since the yield can be stabilized, it is a technique that is indispensable when, for example, flattening an interlayer insulating film and a BPSG film and performing shallow trench isolation.

Conventionally, in a manufacturing process of a semiconductor device, a plasma CVD (Chemical Vapor Depth) is used.
As a polishing method for flattening an inorganic insulating film such as a silicon oxide insulating film formed by a method such as oxidation, chemical vapor deposition, or low-pressure CVD, a substrate on which a film to be polished is formed is pressed against a CMP pad. Pressurizing and supplying the polishing agent between the polishing film and the CMP pad,
I am moving the P pad.

At this time, fumed silica-based polishing cloth is generally used as an abrasive, and urethane foam-based polishing cloth is generally used as a CMP pad. However, such a polishing method does not have a sufficient polishing rate for the inorganic insulating film, and there is a technical problem of a low polishing rate for practical use.

Further, when polishing is performed using the above-mentioned urethane foam-based polishing cloth, it is necessary to periodically perform a pretreatment called dressing. This is because polishing dust generated during polishing clogs the pores of the urethane foam. However, it cannot be said that the conventional dressing process accurately controls the surface state of the CMP pad, and as a result, the polishing characteristics are unstable. Further, in the CMP technique for flattening an interlayer film, it is necessary to end polishing in the middle of the interlayer film, and a process management method of controlling a polishing amount by a polishing time is generally performed. However, not only the change in the pattern step shape, but also the state of the CMP pad, etc., causes a significant change in the polishing rate, which causes a problem that process management is difficult. Furthermore, it was not clear how to control the state of the CMP pad to obtain a stable polishing rate.

On the other hand, cerium oxide abrasives are currently attracting attention as abrasives having a high polishing rate and low polishing scratches, and a CMP pad optimal for such cerium oxide abrasives is desired.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to efficiently and quickly polish a substrate such as a silicon oxide film in a CMP technique for planarizing an interlayer insulating film, a BPSG film, and an insulating film for isolating a shallow trench. For cerium oxide abrasives that can be used and process management can be easily performed
An object of the present invention is to provide a method for polishing a P pad and a substrate using the same.

[0008]

SUMMARY OF THE INVENTION The present invention provides a pad having fine irregularities on a surface for chemically and mechanically polishing a thin film formed on a substrate using a cerium oxide abrasive. The present invention relates to a CMP pad for a cerium oxide abrasive, wherein the center line average surface roughness Ra is defined by a ratio of the abrasive particle to a D99% particle diameter measured by a laser scattering type particle size distribution meter.

[0009] The particle size of the cerium oxide particles contained in the cerium oxide abrasive can be measured with a laser scattering particle size distribution analyzer (for example, a measuring device, Mastersizer Mic manufactured by Malvern Instruments).
roplus, light source He-Ne laser, refractive index of particles 1.9
285, measured at 0 absorption).

When the substrate is polished using a CMP pad having a ratio of the center line average surface roughness Ra to the D99% particle size of the abrasive particles measured by a laser scattering type particle size distribution analyzer of 0.2 to 1.3, Very high polishing rates can be obtained.

In the case of a CMP pad in which the ratio of the center line average surface roughness Ra of the pad surface to the D99% particle size of the abrasive particles measured by a laser scattering type particle size distribution analyzer is 2 to 20, the polishing rate is set to the CMP rate. It becomes insensitive to changes in the surface roughness of the pad, and as a result, stable polishing characteristics can be obtained.

The present invention also provides a method in which the substrate or the polishing platen is moved while pressing the substrate against the above-mentioned CMP pad for cerium oxide abrasive and supplying the cerium oxide abrasive between the polishing film and the CMP pad. The present invention relates to a method for polishing a substrate, characterized by polishing a polishing film. The substrate polishing method of the present invention is suitably used, for example, for polishing a substrate on which an SiO ₂ insulating film is formed.

Furthermore, during polishing, the ratio of the center line average surface roughness Ra of the pad surface to the D99% particle size of the abrasive particles measured by a laser scattering type particle size distribution analyzer is intentionally preferably 0.2 to 1%. By changing between 0.3 and 2 to 20, polishing can be performed while controlling the polishing rate.

The cerium oxide abrasive used in the method of polishing a substrate of the present invention preferably has abrasive grains of polycrystalline cerium oxide.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS C for cerium oxide abrasive of the present invention
The MP pad will be described with reference to FIG. FIG. 1 is a graph showing the relationship between the polishing rate, the center line average surface roughness Ra of the pad surface, and the ratio of the D99% particle size of the abrasive particles measured by a laser scattering type particle size distribution meter. The abrasive used is preferably polycrystalline cerium oxide and has a D99% particle size of 1 μm.
More preferably, two types of polycrystalline cerium oxides, m and 0.6 μm, are used. Even if the D99% particle size is different, the ratio between the center line average surface roughness Ra of the pad surface and the D99% particle size of the abrasive particles measured by the laser scattering type particle size distribution analyzer is plotted on the substantially same curve. I found out. As shown in FIG. 1, a substrate was prepared using a CMP pad in which the ratio of the center line average surface roughness Ra to the D99% particle size of abrasive particles measured by a laser scattering type particle size distribution analyzer was 0.2 or more and 1.3 or less. , A very high polishing rate can be obtained. If the ratio is less than 0.2, the particles cannot be retained, and the polishing rate decreases. If it is larger than 1.3, the polishing rate decreases with Ra, but if it is 2 or more, the polishing rate becomes constant regardless of the roughness of the pad surface. That is, the ratio between the center line average surface roughness Ra of the pad surface and the D99% particle size of the abrasive particles measured by the laser scattering type particle size distribution analyzer is:
By using a CMP pad of 2 to 20, it is possible to obtain a polishing rate with little change with respect to a change in pad surface roughness during polishing or due to a dressing process. The center line average surface roughness Ra is JIS B 0601
In accordance with 3.1, for example, surface profile measuring device: DEK
TAK3030 (Sloan Technology)
Division Veeco Instrument
s), stylus tip radius: 12.5 μm, stylus load at measurement: 3 mgf, measurement distance: 1 mm, measurement speed: 20 μm
/ Sec, number of measurements: Measured under the condition of 5 points on the pad arbitrarily (avoid the end and center of the pad where the dresser does not reach). The D99% particle size of the abrasive particles is measured, for example, by
Laser diffraction method (measuring device: microplus manufactured by Master Size, refractive index: 1.9285, light source: H
(e-Ne laser). Also, D
99% means the particle diameter when the volume ratio of the particles is integrated from the finer particles in the volume particle diameter distribution and reaches 99%.

As a method of forming fine irregularities on the surface of the CMP pad in the present invention, there is the above-mentioned dressing treatment, that is, a method of shaving the surface of the CMP pad using a diamond grindstone. Instead of a diamond grindstone, a wire brush, a metal scraper, a resin brush, glass or an alumina ceramics plate may be used. Further, fine irregularities on the pad surface may be formed simultaneously with polishing of the substrate without dressing. Also, the particles are sprayed on a CMP pad to form fine irregularities, or a mold having fine irregularities is formed by applying heat or pressure to the mold.
The transfer may be performed by a method of pressing against the surface of the MP pad.

As the material of the CMP pad used in the present invention, in addition to foamed resin such as urethane foam, a material which can be chemically and thermally formed into a sheet or plate can be used. Examples thereof include polyolefins such as polyethylene and polypropylene, cellulose derivatives such as cellulose acetate, acrylic resins, various epoxy resins, polyamides, polystyrenes, polycarbonates, polyimides, nylons, polyesters, and copolymer resins such as ABS resins.

Generally, cerium oxide is carbonate, nitrate,
It is obtained by oxidizing cerium compounds of sulfate and oxalate. A cerium oxide abrasive used for polishing a silicon oxide film formed by a TEOS-CVD method or the like can perform high-speed polishing as the primary particle diameter is larger and the crystal distortion is smaller, that is, the crystallinity is better. Polishing scratches tend to occur. Thus, the method for producing the cerium oxide particles used in the present invention is not limited, but the cerium oxide crystallite diameter is preferably 5 nm or more and 300 nm or less. Further, since it is used for polishing a semiconductor chip, the content of alkali metals and halogens is preferably suppressed to 10 ppm or less in the cerium oxide particles.

As a method for producing the cerium oxide powder used in the present invention using the above-mentioned cerium compound, a calcination method or an oxidation method using hydrogen peroxide or the like can be used. Firing temperature is 3
The temperature is preferably from 50 ° C to 900 ° C.

Since the cerium oxide particles produced by the above method are agglomerated, it is preferable to mechanically pulverize them. As the pulverization method, a dry pulverization method using a jet mill or the like or a wet pulverization method using a planetary bead mill or the like is preferable. The jet mill is described in, for example, Chemical Industry Transactions, Vol.
80) pages 527-532.

The CMP abrasive used in the present invention can be obtained, for example, by dispersing a composition comprising cerium oxide particles having the above characteristics, a dispersant, and water, and further adding an additive. Here, the concentration of the cerium oxide particles is not limited, but is preferably in the range of 0.5% by weight or more and 20% by weight or less from the viewpoint of easy handling of the dispersion. In addition, since it is used as a dispersant for polishing semiconductor chips, the content of alkali metals such as sodium ions and potassium ions, halogens, and sulfur is preferably suppressed to 10 ppm or less. For example, ammonium acrylate as a copolymerization component A polymer dispersant containing is preferred. Also selected from a polymer dispersant containing ammonium acrylate as a copolymer component and a water-soluble anionic dispersant, a water-soluble nonionic dispersant, a water-soluble cationic dispersant, and a water-soluble amphoteric dispersant. Two or more dispersants including at least one dispersant may be used. Examples of the water-soluble anionic dispersant include triethanolamine lauryl sulfate, ammonium lauryl sulfate, polyoxyethylene alkyl ether triethanolamine sulfate, a special polycarboxylic acid type polymer dispersant, and the like. As the dispersant, for example, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene higher alcohol ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether , Polyoxyalkylene alkyl ether, polyoxyethylene derivative, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate , Polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbit tetraoleate, polyethylene glycol monolaurate,
Polyethylene glycol monostearate, polyethylene glycol distearate, polyethylene glycol monooleate, polyoxyethylene alkylamine,
Polyoxyethylene hydrogenated castor oil, alkyl alkanolamides, and the like.Examples of the water-soluble cationic dispersant include polyvinylpyrrolidone, coconutamine acetate, stearylamine acetate, and the like. For example, lauryl betaine, stearyl betaine, lauryl dimethylamine oxide, 2-alkyl-N-carboxymethyl-N-
Hydroxyethyl imidazolinium betaine and the like. These dispersant addition amounts are 0.03 parts by weight based on 100 parts by weight of the cerium oxide particles from the relationship between the dispersibility of the particles in the slurry and the prevention of sedimentation, and the relationship between the polishing scratches and the dispersant addition amount.
The range is preferably from 1 part by weight to 2.0 parts by weight. The molecular weight of the dispersant is preferably from 100 to 50,000,
000 to 10,000 is more preferred. When the molecular weight of the dispersant is less than 100, a sufficient polishing rate cannot be obtained when polishing the silicon oxide film or the silicon nitride film, and when the molecular weight of the dispersant exceeds 50,000, the viscosity becomes high. This is because the storage stability of the CMP abrasive tends to decrease.

As a method of dispersing these cerium oxide particles in water, a homogenizer, an ultrasonic disperser, a wet ball mill, or the like can be used in addition to the usual dispersion treatment using a stirrer.

The average particle size of the cerium oxide particles in the thus prepared CMP abrasive is 0.01 μm to 1.0 μm.
It is preferable that If the average particle size of the cerium oxide particles is less than 0.01 μm, the polishing rate is too low,
If the thickness exceeds 1.0 μm, the film to be polished tends to be easily damaged.

As a method of forming an inorganic insulating film using the CMP polishing slurry of the present invention, low pressure CVD, plasma CVD, etc.
And the like. In forming a silicon oxide film by a low-pressure CVD method, monosilane: SiH _{4 is} used as a Si source, and oxygen: O ₂ is used as an oxygen source. It can be obtained by performing this SiH ₄ —O ₂ -based oxidation reaction at a low temperature of 400 ° C. or less. In some cases, heat treatment is performed at a temperature of 1000 ° C. or lower after CVD. When doping phosphorus: P for planarization of the surface by high-temperature reflow, SiH ₄ —O
It is preferred to use ₂ -PH ₃ system reaction gas. The plasma CVD method has an advantage that a chemical reaction requiring a high temperature can be performed at a low temperature under normal thermal equilibrium. The plasma generation method includes two types, a capacitive coupling type and an inductive coupling type. As a reaction gas, SiH ₄ as a Si source and N as an oxygen source
₂ O The _SiH 4 -N ₂ O-based gas and _{TEOS-O 2} based gas of tetraethoxysilane (TEOS) was used in the Si source used (TEOS-plasma CVD method). The substrate temperature is 250 ° C to 400 ° C, and the reaction pressure is 67 to 400.
The range of Pa is preferable. As described above, the silicon oxide film of the present invention may be doped with elements such as phosphorus and boron. Similarly, silicon nitride film formation by low pressure CVD
Dichlorosilane: SiH ₂ Cl ₂ is used as an i source, and ammonia: NH ₃ is used as a nitrogen source. This SiH ₂ Cl ₂
It can be obtained by performing an —NH ₃ -based oxidation reaction at a high temperature of 900 ° C. In the plasma CVD method, a SiH ₄ -NH ₃ gas using SiH ₄ as a Si source and NH ₃ as a nitrogen source is used as a reaction gas. Substrate temperature is 3
00 ° C to 400 ° C is preferred.

As the substrate, a semiconductor substrate, that is, a semiconductor substrate in which circuit elements and wiring patterns are formed, or a substrate in which a silicon oxide film layer or a silicon nitride film layer is formed on a semiconductor substrate in which circuit elements are formed, is used. Can be used. By polishing the silicon oxide film layer or the silicon nitride film layer formed on such a semiconductor substrate with the above-mentioned CMP polishing agent, irregularities on the surface of the silicon oxide film layer or the silicon nitride film layer are eliminated, and the entire surface of the semiconductor substrate is removed. It can be a smooth surface. It can also be used for shallow trench isolation.

The apparatus for polishing is not limited, and can be used in a disk-type polishing apparatus, a linear-type polishing apparatus, and a web-type polishing apparatus. As an example, there is a general polishing apparatus having a holder for holding a semiconductor substrate and a surface plate on which a polishing cloth (pad) is attached (a motor or the like whose rotation speed can be changed is attached). The polishing conditions are not limited, but the pressure applied to the semiconductor substrate is 0.1 MPa so as not to cause scratches after polishing.
The following is preferred. During polishing, slurry is continuously supplied to the CMP pad by a pump or the like. Although the supply amount is not limited, it is preferable that the surface of the polishing pad is always covered with the slurry.

After the polishing is completed, the semiconductor substrate is preferably washed well in running water, and then dried using a spin drier or the like to remove water droplets adhering to the semiconductor substrate. After forming the shallow trench thus flattened, an aluminum wiring is formed on the silicon oxide insulating film layer, and a silicon oxide insulating film is formed again between the wirings and on the wiring by the above method. By polishing using the above-mentioned CMP polishing agent and pad, unevenness on the surface of the insulating film is eliminated, and a smooth surface is formed over the entire semiconductor substrate.
By repeating this process a predetermined number of times, a semiconductor having a desired number of layers is manufactured.

The CMP pad of the present invention includes not only a silicon oxide film formed on a semiconductor substrate, but also a silicon oxide film formed on a wiring board having predetermined wiring, glass, an inorganic insulating film such as silicon nitride, polysilicon, or the like. , Al, Cu, Ti, TiN,
A film mainly containing W, Ta, TaN, etc., an optical glass such as a photomask / lens / prism, an inorganic conductive film such as ITO, an optical integrated circuit / optical switching element / optical waveguide composed of glass and a crystalline material, Optical fiber end face, optical single crystal such as scintillator, solid-state laser single crystal, sapphire substrate for blue laser LED, SiC, Ga
A semiconductor single crystal such as P or GaAs, a glass substrate for a magnetic disk, a magnetic head, or the like can be polished.

[0029]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. Example 1 (Surface treatment of CMP pad) Flat plate AB having a thickness of 2.0 mm
Using # 70, # 150 and # 400 diamond grindstones for S resin sheet, pressure 9.0 kPa, rotation 38r
Dressing was performed at pm for 20 minutes. AB
The surface roughened copper foil was placed on the S resin sheet, and the unevenness of the copper foil surface was transferred by pressing. By these treatments, the center line average surface roughness Ra of the surface is 0.05 to 6 μm.
m CMP pads were obtained.

(Preparation of Cerium Oxide Particles) 2 kg of cerium carbonate hydrate was placed in a platinum container and calcined at 800 ° C. for 2 hours in the air to obtain about 1 kg of yellowish white powder. When this powder was subjected to phase identification by an X-ray diffraction method, it was confirmed that the powder was cerium oxide. The calcined powder particle size is 30
１００100 μm. When the surface of the fired powder particles was observed with a scanning electron microscope, grain boundaries of cerium oxide were observed. When the primary particle diameter of cerium oxide surrounded by the grain boundaries was measured, the median of the volume distribution was 190 nm and the maximum was 5 nm.
00 nm. 1 kg of cerium oxide powder was dry-ground using a jet mill. Observation of the pulverized particles with a scanning electron microscope revealed that in addition to the small particles having the same size as the primary particle diameter, large pulverized residual particles of 1 to 3 μm and pulverized residual particles of 0.5 to 1 μm were mixed.

(Preparation of Cerium Oxide Slurry) 1 kg of the cerium oxide particles prepared above, 23 g of an aqueous solution of ammonium polyacrylate (40% by weight), and deionized water 8977
g was mixed and subjected to ultrasonic dispersion for 10 minutes while stirring. The obtained slurry was filtered through a 1-micron filter, and further 5% by weight of slurry was obtained by adding deionized water. The slurry pH was 8.3. As a result of diluting the slurry particles to an appropriate concentration in order to measure them with a laser diffraction type particle size distribution meter, the D99% particle size was found to be 0.9.
It was 9 μm.

(Polishing of insulating film layer) A silicon oxide film was formed on a 127 mm Si substrate by a TEOS-plasma CVD method.
A blanket wafer having a thickness of 00 nm is manufactured. The wafer was set on a holder to which a suction pad for attaching a substrate to be held was attached, and the holder was placed with the insulating film face down on a φ380 mm platen to which the above-prepared CMP pads having various surface roughness were attached. , And the processing load was set to 30.0 kPa. 150 cc / mi of the above cerium oxide abrasive (solid content: 1% by weight) on a surface plate
While dropping at a speed of n, the platen and the wafer were rotated at 38 rpm.
For 2 minutes to polish the insulating film. The polished wafer was thoroughly washed with pure water and then dried. The difference in film thickness before and after polishing was measured using an optical interference type film thickness measuring device, and the polishing rate was calculated. Polishing rate and center line average surface roughness R of pad surface
a is shown in FIG.

Example 2 The cerium oxide slurry prepared in Example 1 was subjected to sedimentation classification. The slurry particles were diluted to an appropriate concentration for measurement by a laser diffraction particle size distribution analyzer, and as a result, the D99% particle size was 0.6 μm. The same insulating film layer as in Example 1 was polished using the same CMP pad as in Example 1, except that a cerium oxide slurry having a D99% particle size of 0.6 μm was used. FIG. 3 shows the polishing rate and the center line average surface roughness Ra of the pad surface. Further, FIG. 1 shows the polishing rates obtained in Examples 1 and 2 expressed by the ratio between the center line average surface roughness Ra of the pad surface and the D99% particle size. Center line average surface roughness Ra of pad surface and D99% of abrasive particles measured by laser scattering type particle size distribution meter
By setting the ratio to the particle size to be at least 0.2 and at most 1.3, a high polishing rate can be obtained.

Example 3 Using a # 70 diamond grindstone on a 2.0 mm thick flat ABS resin sheet, a pressure of 9.0 kPa and a rotation of 3
The dressing was performed at 8 rpm for 20 minutes. By this treatment, a CMP pad having a center line average surface roughness Ra of 6 μm was obtained. Thereafter, the insulating film layer was polished using this CMP pad, and the stability of the polishing rate without dressing between the substrates was examined. The polishing conditions for the cerium oxide slurry and the insulating film layer used for polishing were the same as those in Example 1.
Is the same as FIG. 4 shows the relationship between the polishing rate and the number of polished substrates. Variation in polishing rate (1σ / average polishing rate ×
100) was 2.5%.

Comparative Example 1 CMP having a center line average surface roughness Ra of 1.8 μm
Polishing was performed in the same manner as in Example 3 except that a pad was used. FIG. 5 shows the relationship between the polishing rate and the number of polished substrates. The polishing rate is not constant, but increases in accordance with the number of pieces polished.
As a result, variations in polishing rate (1σ / average polishing rate ×
100) was 25%.

Example 4 A # 70 diamond whetstone was used between substrates to be polished.
And pressure 90g / cm ²At 38 rpm for 1 minute
Polishing was performed in the same manner as in Example 3 except for performing a shinging process. Laboratory
FIG. 6 shows the relationship between the polishing rate and the number of polished substrates. Polishing speed
The degree of dispersion (1σ / average polishing rate × 100) is 3.3.
%Met.

Comparative Example 2 CMP in which the center line average surface roughness Ra of the surface is 1.8 μm
Using a pad and using a # 400 diamond grindstone between substrates to be polished, at a pressure of 9.0 kPa and a rotation of 38 rpm
The polishing was performed in the same manner as in Example 3 except that the dressing treatment was performed at m for 1 minute. FIG. 7 shows the relationship between the polishing rate and the number of polished substrates.
Shown in As a result, the variation in the polishing rate (1σ / average polishing rate × 100) was 13%.

[0038]

The center line average surface roughness R of the surface of the present invention
a is defined by the ratio of a to the D99% particle size of the abrasive particles.
By a pad and a polishing method of a substrate using the pad,
The step of flattening the interlayer insulating film and the BPSG (silicon dioxide film doped with boron and phosphorus) film and the step of forming shallow trench isolation can be efficiently and easily performed.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the ratio of the abrasive particle diameter to the center line average surface roughness Ra of the pad surface and the polishing rate.

FIG. 2 is a graph showing the relationship between the center line average surface roughness Ra of the pad surface and the polishing rate when the abrasive particle diameter is 1 μm.

FIG. 3 is a graph showing the relationship between the center line average surface roughness Ra of the pad surface and the polishing rate when the abrasive particle diameter is 0.6 μm.

FIG. 4 shows a center line average surface roughness Ra6.0 of a pad surface.
7 is a graph showing the relationship between the number of polished wafers and the polishing rate when used without dressing at μm.

FIG. 5: Center line average surface roughness Ra1.8 of the pad surface
7 is a graph showing the relationship between the number of polished wafers and the polishing rate when used without dressing at μm.

FIG. 6: Center line average surface roughness Ra6.0 of the pad surface
9 is a graph showing the relationship between the number of polished wafers and the polishing rate when used with dressing at μm.

FIG. 7 shows a center line average surface roughness Ra1.8 of the pad surface.
9 is a graph showing the relationship between the number of polished wafers and the polishing rate when used with dressing at μm.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Hiroshi Nakagawa 4-13-1, Higashicho, Hitachi City, Ibaraki Pref. Hitachi Chemical Co., Ltd. Yamazaki Office F-term (reference)

Claims (7)

[Claims] 1. A pad having fine irregularities on a surface for chemically and mechanically polishing a thin film formed on a substrate using a cerium oxide abrasive, wherein a center line average surface roughness Ra of the pad surface is a laser. A CMP pad for a cerium oxide abrasive, characterized in that it is defined by a ratio of the abrasive particles to a D99% particle size measured by a scattering type particle size distribution meter. 2. The center line average surface roughness Ra of the pad surface
Of abrasive particles measured with a laser scattering particle size distribution analyzer
The CMP pad for a cerium oxide abrasive according to claim 1, wherein a ratio with respect to a 9% particle size is 0.2 or more and 1.3 or less. 3. The center line average surface roughness Ra of the pad surface
Of abrasive particles measured with a laser scattering particle size distribution analyzer
The CMP pad for a cerium oxide abrasive according to claim 1, wherein a ratio to a 9% particle size is 2 to 20. 4. A substrate or a polishing platen while pressing a substrate against the CMP pad for cerium oxide abrasive according to claim 1 and supplying the cerium oxide abrasive between the polishing film and the CMP pad. A polishing method for a substrate, characterized by polishing a polishing film by moving a substrate. 5. The method for polishing a substrate according to claim 4, wherein the substrate is a substrate on which an SiO ₂ insulating film is formed. 6. The polishing method according to claim 4, wherein the ratio between the center line average surface roughness Ra of the pad surface during polishing and the D99% particle size of the abrasive particles measured by a laser scattering type particle size distribution meter is changed during polishing.
5. The method for polishing a substrate according to any one of 5. 7. The method for polishing a substrate according to claim 4, wherein the abrasive grains of the cerium oxide abrasive are polycrystalline cerium oxide.