JP2001007061A - Cmp-polishing agent and method for polishing substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To polish a surface without flaws at a high speed for making high planarity by comprising a low-molecular additive selected from among cerium oxide particle, dispersant, and cationic water-soluble organic low-molecule, in short a specified amine or ammonium, as well as water. SOLUTION: A low-molecular additive, as well as water, selected from among cerium oxide particles, dispersant, and cationic water-soluble organic low- molecule which is a first class amine, second class amine, third class amine or fourth class ammonium, are included in this polishing agent. So, under a high polishing load, a cerium oxide particle breaks through the coat of additive formed on a surface to be polished to increase a polishing speed. If roughness exists on the surface to be polished, since effective polishing load at a protruding part is larger than a recessed part, the protruding part is selectively polished to accomplish making global planarity with less dependency on a pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CMP polishing agent used in a flattening process of a substrate surface, which is a semiconductor device manufacturing technology, in particular, a flattening process of an interlayer insulating film, a forming process of shallow trench isolation, and the like. The present invention relates to a method for polishing a substrate using these CMP abrasives.

[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, the technique is indispensable when performing, for example, planarization of an interlayer insulating film, isolation of a shallow trench, and the like. Conventionally, in a semiconductor device manufacturing process, plasma-CVD (Chemical Vapor Depositio
n, chemical vapor deposition), C for planarizing an inorganic insulating film layer such as a silicon oxide insulating film formed by a method such as low pressure-CVD.
Fumed silica-based abrasives have been generally studied as MP abrasives. Fumed silica abrasives
The silica particles are produced by growing particles by a method such as thermal decomposition of tetrachlorosilicic acid and adjusting the pH. However,
Such an abrasive does not have a sufficient polishing rate for the inorganic insulating film, and there has been a technical problem of a low polishing rate for practical use. In the conventional CMP technique for planarizing an interlayer insulating film, the polishing rate greatly depends on the pattern of a film to be polished on a substrate, and the polishing rate of a convex portion differs greatly depending on the pattern density difference or the size difference. Therefore, there has been a technical problem that high-level planarization over the entire surface of the wafer cannot be realized. 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, there has been a problem that not only the change in the pattern step shape but also the state of the polishing cloth significantly changes the polishing rate, making process management difficult. In the generation of the design rule of 0.5 μm or more, LOCOS (local oxidation of silicon) has been used for element isolation in an integrated circuit. After that, when the processing size becomes finer, the technology of narrow element isolation width is required,
Shallow trench isolation is being used. In the shallow trench isolation, CMP is used to remove an excess silicon oxide film formed on the substrate, and a stopper film having a low polishing rate is formed below the silicon oxide film to stop polishing. Silicon nitride or the like is used for the stopper film, and it is desirable that the polishing rate ratio between the silicon oxide film and the stopper film is large.

On the other hand, cerium oxide abrasives have been used as abrasives for glass surfaces such as photomasks and lenses. Cerium oxide particles have a lower hardness than silica particles and alumina particles and are therefore less likely to scratch the polished surface, and thus are useful for finish mirror polishing. However, since a cerium oxide abrasive for polishing a glass surface uses a dispersant containing a sodium salt, it cannot be directly used as an abrasive for semiconductors.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a CMP polishing agent which can be highly planarized and can be polished at high speed without damaging the surface to be polished such as a silicon oxide insulating film. It is intended to provide a CMP polishing agent having improved. The present invention also provides a substrate polishing method capable of polishing a surface to be polished of a substrate without flaws.

[0005]

The CMP abrasive of the present invention is a cerium oxide particle, a dispersant, a cationic amine, a primary amine, a secondary amine, a tertiary amine or a quaternary ammonium. It contains a low molecular additive selected from water-soluble organic low molecules and water. The CMP polishing slurry of the present invention can be composed of a cerium oxide slurry containing cerium oxide particles, a dispersant and water, and an additive solution containing a molecular additive and water. In the polishing method of the present invention, the substrate on which the film to be polished is formed is pressed against a polishing cloth of a polishing platen and pressurized. The board is moved to polish the film to be polished.

[0006]

DETAILED DESCRIPTION OF THE INVENTION Generally, cerium oxide is a carbonate,
It is obtained by oxidizing cerium compounds of nitrates, sulfates and oxalates. 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. Therefore, the cerium oxide particles used in the present invention are not limited to a method for producing the cerium oxide particles.
It is preferably 0 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.

In the present invention, as a method for producing cerium oxide powder, calcination or an oxidation method using hydrogen peroxide or the like can be used. The firing temperature is preferably from 350 ° C. to 900 ° C. Since the cerium oxide particles produced by the above method are agglomerated, it is preferable to mechanically pulverize the particles. 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. 6, No. 5 (198
0) pages 527-532.

[0008] The CMP abrasive in the present invention is, for example,
It is obtained by dispersing a composition comprising cerium oxide particles having the above characteristics, a dispersant, and water, and further adding a low-molecular additive. Here, the concentration of the cerium oxide particles is not limited, but is preferably 0.5% because of easy handling of the dispersion.
The range is preferably from 20% by weight to 20% by weight. 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, 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. Examples of the dispersant include polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene higher alcohol ether, polyoxyethylene octyl phenyl ether, and 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 sorbite tetraoleate, polyethylene glycol monolaurate, polyethylene glycol mono Stearate, polyethylene glycol distearate, polyethylene glycol monooleate, polyoxyethylene alkylamine, polyoxyethylene hydrogenated castor oil, alkyl alkanolamide, and the like.Examples of the water-soluble cationic dispersant include coconut Amine acetate, stearylamine acetate, and the like. Examples of the water-soluble amphoteric dispersant include lauryl betaine and stearyl betaine. Emissions, lauryl dimethylamine oxide, 2-alkyl -N- carboxymethyl -N- hydroxyethyl imidazolinium betaine. These dispersing agents are added in an amount of 0.01 to 2.0 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 amount of the dispersing agent added. A range of not more than parts by weight is preferred. The molecular weight of the dispersant is 100
~ 50,000 is preferable, and 1,000 ~ 10,000
Is more preferred. When the molecular weight of the dispersant is less than 100, when polishing a silicon oxide film or a silicon nitride film,
A sufficient polishing rate was not obtained, and the molecular weight of the dispersant was 50,0.
If it exceeds 00, the viscosity becomes high, and the storage stability of the CMP abrasive decreases. Methods for dispersing these cerium oxide particles in water include homogenizers, ultrasonic dispersers, as well as dispersion treatments using ordinary stirrers.
A wet ball mill or the like can be used. The average particle size of the cerium oxide particles in the CMP polishing slurry thus produced is preferably 0.01 μm to 1.0 μm.
If the average particle size of the cerium oxide particles is less than 0.01 μm, the polishing rate is too low, and if it exceeds 1.0 μm, the film to be polished is easily damaged.

The low molecular additives include methylamine,
Dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, n-propylamine, di-n-propylamine, tri-n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, tert-butylamine, valerylamine, Isovalerylamine, cyclohexylamine, benzylamine, α-phenylethylamine, β-phenylethylamine, ethylenediamine,
Trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, tetramethylenediamine hydroxide, aniline, methylaniline,
Dimethylaniline, o-toluidine, m-toluidine,
p-toluidine, o-anisidine, m-anisidine, p
-Anisidine, m-chloroaniline, p-chloroaniline, o-nitroaniline, m-nitroaniline, p-nitroaniline, 2,4-dinitroaniline, picramide, o-phenylenediamine, m-phenylenediamine, p-phenylene Diamine, benzidine, sulfanilic acid, acetamidine, 2-anilinoethanol, anilinophenol, aminoacetanilide, aminoacetophenone, 2-aminoethanol, 2-aminoethanethiol, 2-amino-2-ethyl-1,3-propane Diol, aminoguanidine, 5-amino-o-cresol, 6-amino-m-cresol, ethyl 3-aminocrotonate, p-aminostyrene, 4-amino-1,2,2,
4-triazole, 4-amino-1-naphthol, 5-
Amino-2-naphthol, 8-amino-2-naphthol,
8-amino-1-naphthol, aminophenol, 2-
Amino-1-butanol, 2-amino-1-propanol, α-aminopropionitrile, p-aminobenzyl alcohol, p-aminobenzaldehyde, 2-amino-2-methyl-1-propanol, 2-amino-2-methyl -1,3-propanediol, 4-amino-4-methyl-2-pentanone, allantoin, allylamine,
Arekaidin, Arecoline, p-isopropylaniline, 2- (ethylamino) -ethanol, N-ethyl-
1-naphthylamine, N-ethyl-2-naphthylamine, O-ethylhydroxylamine, N-ethylbenzamide, ephedrine, oxamic acid, xylidine, p
-Xylene-α, α′-diamine, quinuclidine, kinetin, quinoxaline, 2-quinolylamine, 4-quinolylamine, glycosiamidine, 3,6-diazaoctane-1,8-diamine, 4,4′-diphenylamine,
2,4-diaminophenol, 3,4-diaminophenol, diisopropylamine, diethanolamine,
-(Diethylamino) -ethanol, diethylcyanamide, diethylenetriamine, cyclopropylamine,
Cyclohexanediamine, N, N'-diphenylethylenediamine, N, N'-diphenylguanidine, 4,
4′-diphenylmethanediamine, 2-dimethylaminoethanol, N, N-dimethyl-2-naphthylamine,
3,5-dimethylpyrazole, dimethylpyridine, N,
N-dimethyl-p-phenylenediamine, 2-thiazolamine, thymilamine, thymine, decahydroquinoline, tetraethylammonium, 1,2,3,4-tetrahydro-1-naphthylamine, 1,2,3,4-tetrahydronaphthylamine, N, N, N ', N'-tetramethylethylenediamine, N, N, N', N'-tetramethyl-p-phenylenediamine, 1,4-butanediamine, 2,4,6-triaminophenol, tri Ethanolamine, trimethylamine oxide, 2,3-toluenediamine, 2,4-toluenediamine, 2,6-toluenediamine, 3,5-toluenediamine, 1,2-
Naphthalenediamine, 1,4-naphthalenediamine,
1,8-naphthalenediamine, 2,6-naphthalenediamine, 2,7-naphthalenediamine, 4,4′-bis (dimethylamino) diphenylamine, bis (dimethylamino) methane, histamine, N, N-bis (2- (Hydroxyethyl) butylamine, vinylamine, 4-biphenylylamine, piperazine, 2,5-piperazinedione, 2-piperidinone, piperidine, 2-pyridylamine, 3-pyridylamine, 4-pyridylamine, pyridine, pyrimidine, pyrrolidine, pyrroline Phenacylamine, N-phenylhydroxylamine, 1-phenyl-2-propanamine, o-phenylenediamine, m-
Phenylenediamine, p-phenylenediamine, phenethylamine, 1,4-butanediamine, 1,2-propanediamine, 1,3-propanediamine, hexamethylenetetramine, 1,6-hexamethylenediamine, N-
Benzylhydroxylamine, O-benzylhydroxylamine, benzhydrylamine, 1,2,3-benzenetriamine, 1,2,4-benzenetriamine, 1,
5-pentanediamine, tert-pentylamine, methylguanidine, N-methylhydroxylamine, O-
Methylhydroxylamine, 2-methylpiperidine, 3
-Methylperidine, 4-methylpiperidine, N-methylpiperidine, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, N-methyl-P-phenylenediamine, 4-methoxypyridine, canosamine, galactosamine, glucosamine, Fusacosamine, mannosamine, N-methylglucosamine, muramic acid, monoalcohol and the like are preferred. In addition, one or more protons of the above compound may be represented by F, Cl, Br, I, OH, CN, N
A derivative substituted with an atom or an atomic group such as O ₂ may be used. Also, aliphatic quaternary ammonium, benzalkonium, benzethonium chloride, pyridinium, imidazolinium, dialkyl monoalcoholamine alkyl ester, dialkylaminoalkylamine-N'-alkylamide, dialkyl monoalcoholamine alkyl ether, trialkyl monoalcohol Amine alkyl ester, trialkylaminoalkylamine-N'-alkylamide, trialkylmonoalcoholamine alkylether, trialkylbenzyl quaternary ammonium salt, dialkylmonoalcoholbenzyl quaternary ammonium salt alkyl ester, dialkylmonoaminobenzyl Quaternary ammonium salt-N-alkyl amide, dialkyl monoalcohol benzyl quaternary ammonium salt alkyl ether, alkyl Jiniumu salts, hydroxyalkyl pyridinium salt alkyl esters, aminoalkyl pyridinium salt -N'- alkyl amides are also preferably used. The amount of the low-molecular additive added is 0.01 parts by weight based on 100 parts by weight of the cerium oxide particles based on the relationship between the dispersibility of the particles in the CMP abrasive and the prevention of sedimentation, and the relationship between polishing scratches and the amount of the additive. The range is preferably not less than 1000 parts by weight and not more than 1000 parts by weight. The molecular weight of the low-molecular additive is 1000
The following is preferred. Cerium oxide particles, a dispersant, and a cerium oxide slurry composed of water and an additive liquid composed of a low-molecular additive and water are stored as a separate CMP polishing agent, so that the cerium oxide particles do not agglomerate, thereby increasing the storage stability. It is preferable because the generation of polishing scratches can be prevented and the polishing rate can be stabilized. When polishing a substrate with the above-mentioned CMP abrasive, the additive liquid is supplied separately to the polishing platen and the cerium oxide slurry, and mixed on the polishing platen, or mixed with the cerium oxide slurry immediately before polishing. The method of supplying on a surface plate is taken.

As the CMP polishing slurry of the present invention, the above-mentioned CMP polishing slurry may be used as it is, but additives such as N, N-diethylethanolamine, N, N-dimethylethanolamine and aminoethylethanolamine are added. And CM
P abrasive can be used.

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 low-pressure CVD, monosilane: SiH _{4 is} used as a Si source, and oxygen: O ₂ is used as an oxygen source. This is obtained by performing the 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 planarizing 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 is used as a Si source, and N 2 is used 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 a substrate, a silicon oxide film layer or a silicon nitride film layer is formed on a semiconductor substrate such as a semiconductor substrate in which circuit elements and wiring patterns are formed, and a semiconductor substrate in which circuit elements are formed. Substrate 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, the unevenness on the surface of the silicon oxide film layer is eliminated,
A smooth surface can be provided over the entire surface of the semiconductor substrate. It can also be used for shallow trench isolation. For use in shallow trench isolation, it is necessary that the ratio of the polishing rate of the silicon oxide film to the polishing rate of the silicon nitride film and the polishing rate of the silicon oxide film / the polishing rate of the silicon nitride film be 10 or more. If the ratio is less than 10, the difference between the polishing rate of the silicon oxide film and the polishing rate of the silicon nitride film is small, and it becomes impossible to stop polishing at a predetermined position when performing shallow trench isolation. When this ratio is 10 or more, the polishing rate of the silicon nitride film is further reduced, and the polishing can be easily stopped, which is more suitable for shallow trench isolation. In addition, in order to use it for shallow trench isolation, it is necessary that the generation of scratches during polishing be small. Here, as a polishing apparatus, a general polishing apparatus having a holder for holding a semiconductor substrate and a platen on which a polishing cloth (pad) is attached (a motor or the like capable of changing the number of rotations is attached) is used. it can. As the polishing cloth, general nonwoven fabric, foamed polyurethane, porous fluororesin and the like can be used, and there is no particular limitation. Further, it is preferable that the polishing cloth is subjected to a groove processing for accumulating a CMP abrasive. The polishing conditions are not limited, but the rotation speed of the platen is preferably 200 rpm or less so that the semiconductor substrate does not jump out, and the pressure applied to the semiconductor substrate is 1 kg / c so as not to cause scratches after polishing.
m ² or less is preferred. During polishing, the slurry is continuously supplied to the polishing cloth 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, irregularities on the surface of the insulating film are eliminated, and a smooth surface is formed over the entire surface of the semiconductor substrate. By repeating this process a predetermined number of times, a semiconductor having a desired number of layers is manufactured.

In order to achieve global planarization, it is necessary that an additive is adsorbed on the surface of the silicon oxide film to form a film. The additive film formed on the silicon oxide film inhibits the action of the cerium oxide particles on the surface of the film to be polished, and as a result, reduces the polishing rate. On the other hand, at a high polishing load, the cerium oxide particles break through the additive film and the polishing rate increases. If the film to be polished (silicon oxide film) has irregularities,
Since the effective polishing load of the convex portion is larger than that of the concave portion, the convex portion is selectively polished, and global flattening with little pattern dependency can be achieved. At a pH of 3 or more, the surface of the silicon oxide film is negatively charged, so that the cationic low-molecular additive of the present invention easily forms an ionic bond with the film to be polished. Therefore, a film can be efficiently formed even with a small amount of additive, so that there is an advantage that a small amount of additive is required.

The CMP polishing slurry of the present invention can be used not only for a silicon oxide film formed on a semiconductor substrate, but also for a silicon oxide film formed on a wiring board having predetermined wiring, an inorganic insulating film such as glass and silicon nitride, and a polycrystalline silicon. Silicon, 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.

[0016]

EXAMPLES Example 1 (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 a 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 particle diameter of the calcined powder was 30 to 100 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 500 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 0.5 to 1
Residual particles of 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. In order to measure the slurry particles with a laser diffraction type particle size distribution analyzer, the slurry particles were diluted to an appropriate concentration and measured.
It was 0 nm. 600 g of the above cerium oxide slurry (solid content: 5% by weight), 15 g of dodecylamine as an additive and 2385 g of deionized water were mixed, and a cerium oxide abrasive (solid content: 1% by weight) to which a surfactant was added was added. Produced. The pH of the abrasive was 8.1. Further, in order to measure the particles in the abrasive with a laser diffraction particle size distribution analyzer, the particles were diluted to an appropriate concentration and measured. As a result, the median value of the particle diameter was 190 nm.

(Polishing of insulating film layer) Line / Space width is 0.05 to 5 mm and height is 100
After forming a 0 nm Al wiring line part, TEO
A patterned wafer having a silicon oxide film formed to a thickness of 2000 nm by S-plasma CVD is manufactured. The pattern 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 φ600 mm platen to which a polishing pad made of porous urethane resin was attached, Further, the processing load is 300 gf / cm ²
Set to. While dropping the cerium oxide abrasive (solid content: 1% by weight) at a rate of 200 cc / min on the platen, the platen and the wafer were rotated at 50 rpm for 2 minutes,
The insulating film was polished. The polished wafer was thoroughly washed with pure water and then dried. Similarly, polishing time is 3 minutes, 4 minutes, 5 minutes,
The pattern wafer was polished for 6 minutes. Using a light interference type film thickness measurement device, measure the film thickness difference before and after polishing,
The polishing rate was calculated. Line / polishing rate of the Line portion of Space width 1 mm R ₁ and Line / polishing rate of the Line portion of Space width 3 mm R _3, and Line / Space polishing rate ratio of the polishing speed R ₅ of the Line portion of width 5 mm R ₅ / R ₁ and R ₃ / R
_{In No. 1} , the value increased with the polishing time during the polishing time of 2 to 4 minutes, and was substantially constant during the polishing time of 4 to 6 minutes.
Polishing time when the pattern width dependence of the polishing rate became constant 4
For minutes, the polishing rate R ₁ of the Line portion of Line / Space Width 1mm is 344 nm / min (amount of polishing 1377nm), Line /
Polishing rate R ₃ of the Line portion of Space width 3mm is 335nm
/ Min (polishing amount 1338nm), Line / Space width 5mm
Polishing rate R ₅ of the Line portion 315 nm / min (amount of polishing 12
59 nm), and the polishing rate ratios R ₅ / R ₁ and R ₃ / R
₁ was 0.91 and 0.97, respectively. Also,
Line of each Line / Space width when polishing time is 5 minutes and 6 minutes
The polishing amount of the portion was almost the same as that in the case of 4 minutes, and it was found that the polishing hardly progressed after 4 minutes.

Comparative Example 1 (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 a 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 particle diameter of the calcined powder was 30 to 100 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 500 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 0.5 to 1
Residual particles of 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 5% by weight of an abrasive was obtained by adding deionized water. The slurry pH was 8.3. 600 g of the above cerium oxide slurry (solid content: 5% by weight) and 2400 g of deionized water were mixed to prepare a cerium oxide abrasive (solid content: 1% by weight). The pH of the abrasive is 7.4
In addition, in order to measure the particles in the abrasive with a laser diffraction type particle size distribution analyzer, the particles were diluted to an appropriate concentration and measured. As a result, the median value of the particle diameter was 190 nm.

(Polishing of insulating film layer) Line / Space width is 0.05-5 mm and height is 100
After forming a line portion of 0 nm Al wiring, TE
A pattern wafer in which a silicon oxide film is formed to a thickness of 2000 nm by an OS-plasma CVD method is manufactured. The pattern 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 φ600 mm platen to which a polishing pad made of porous urethane resin was attached, Further processing load is 300g / cm ²
Set to. While the cerium oxide slurry (solid content: 1% by weight) was dropped at a rate of 200 cc / min on the platen, the platen and the wafer were rotated at 50 rpm for 1 minute to polish the insulating film. The polished wafer was thoroughly washed with pure water and then dried. Similarly, the polishing of the pattern wafer was performed with a polishing time of 1.5 minutes and 2 minutes. Line / Space
Polishing rate of the Line portion of width 1 mm R ₁ and Line / Space Width 3
Polishing speed R ₃ of Line part of mm and Line / Space width 5
polishing rate ratio between the polishing rate R ₅ of the Line portion of mm R ₅ / R
₁ and R ₃ / R ₁ were almost constant during the polishing time of 1 to 2 minutes. When the polishing time is 1.5 minutes in which the pattern width dependence of the polishing rate is constant depending on the polishing time, Line / Spac
e polishing rate R ₁ of the Line portion of the width 1mm is 811 nm / min (amount of polishing 1216nm), Line / Space Width 3mm of Line
The polishing rate R _{3 of the} portion is 616 nm / min (the polishing amount is 924 n
m), Line / Space Polishing rate R _{5 of} a line part with a width of 5 mm
Was 497 nm / min (polishing amount: 746 nm), and the polishing rate ratios R ₅ / R ₁ and R ₃ / R ₁ were 0.61 and 0.76, respectively. With a polishing time of 2 minutes, Line / Space
In the Line portion having a width of 0.05 to 1 mm, the polishing reached the Al wiring underlying the silicon oxide film.

Comparative Example 2 (Polishing of insulating film layer) Line / Sp
ace Al with width of 0.05-5mm and height of 1000nm
After forming the line portion of the wiring, a patterned wafer having a 2000 nm-thick silicon oxide film formed thereon by TEOS-plasma CVD is manufactured. Polishing was performed for 2 minutes using a commercially available silica slurry in the same manner as in the example. The p of this commercial slurry
H is 10.3 and contains 12.5 wt% of SiO ₂ particles. The polishing conditions are the same as in the embodiment. Similarly, the pattern wafer was polished by setting the polishing time to 3 minutes, 4 minutes, 5 minutes, and 6 minutes. 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 R ₁ of the Line portion of Line / Space Width 1mm
Line / Space Polishing rate R ₃ of 3 mm wide Line portion, and
Line / polishing rate ratio between the polishing rate R ₅ of the Line portion of Space width 5 mm R ₅ / R ₁ and R ₃ / R _1, the polishing time 2-5
During the minute, the value increased with the polishing time, and was substantially constant in the polishing time of 5 to 6 minutes. If the polishing time is 5 minutes when the dependence of the polishing rate on the pattern width is constant, Line / Sp
polishing rate R ₁ of the Line portion of ace width 1mm is 283 nm /
Min (polishing amount 1416nm), Line / Space 3mm width Li
The polishing rate R ₃ of the ne portion is 218 nm / min (polishing amount 109
2 nm), the polishing rate R ₅ of the Line portion of Line / Space Width 5mm is 169 nm / min (amount of polishing 846 nm), the polishing rate ratio R ₅ / R ₁ and R ₃ / R ₁ are each 0.6
0 and 0.77. When the polishing time is 6 minutes, the polishing rate at the line portion of each Line / Space width is almost the same as that at 5 minutes, and after the polishing rate dependence becomes constant, the polishing rate remains the same. It was found that the polishing proceeded.

[0023]

The CMP polishing slurry of the present invention can be highly planarized, can polish a surface to be polished such as a silicon oxide insulating film at high speed, and has excellent storage stability. In addition, by the polishing method of the present invention, the surface to be polished of the substrate, without scratches,
Polishing becomes possible.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09K 13/00 C09K 13/00 (72) Inventor Masato Yoshida 48 Wadai, Tsukuba, Ibaraki Prefecture Hitachi Chemical Co., Ltd. Inside Tsukuba Research Laboratory (72) Inventor Toranosuke Ashizawa 4-3-1 Higashicho, Hitachi City, Ibaraki Prefecture Hitachi Chemical Co., Ltd.Ibaraki Research Laboratory F-term (reference)

Claims (3)

[Claims] Cerium oxide particles, a dispersant, and a low molecular additive selected from water-soluble organic low molecules that are cationic and are primary amine, secondary amine, tertiary amine or quaternary ammonium. And a CMP polishing slurry containing water. 2. The CMP polishing slurry according to claim 1, comprising a cerium oxide slurry containing cerium oxide particles, a dispersant and water, and an additive solution containing a low-molecular additive and water. 3. A substrate on which a film to be polished is formed is pressed against a polishing cloth of a polishing platen and pressurized, and the CMP polishing agent according to claim 1 or 2 is supplied between the polishing film and the polishing cloth. A substrate polishing method for polishing a film to be polished by moving a polishing platen.