JP2000256654A - Cmp abrasive material and abrasion of substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide CMP abrasive material which is easy in waste liquor treatment, capable of abrading the surface to be abraded of a silicon oxide film and the like at high speed without a mark, and renders a ratio of the abrasion rate of the silicon oxide film to that of silicon nitride film of not smaller than 10, and a method of abrading substrates by using these CMP abrasive materials. SOLUTION: The abrasive material is composed of cerium oxide particles, a cerium oxide slurry containing a dispersing agent and water, and an additive liquid containing a biodegradable additive and water. The additive liquid containing a biodegradable additive is preserved at a pH of not lower than 10 or at a pH of not higher than 5. A method of abrading a substrate comprises pressing a substrate on which a film to be abraded has been formed to the abrasive cloth of an abrasion surface plate, pressurizing the substrate, and operating the substrate and the abrasion surface plate while supplying the CMP abrasive material between the film to be abraded and the abrasive cloth to effect the abrasion of the film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method used in a semiconductor device manufacturing technique, and more particularly to a polishing method for a substrate surface, particularly for an interlayer insulating film and a shallow trench isolation forming step. CMP polishing agent.
And 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 manufacturing process of a semiconductor device, a plasma CVD (Chemical Vapor Depth) is used.
fumed silica-based polishing agents are generally considered as CMP polishing agents for planarizing an inorganic insulating film layer such as a silicon oxide insulating film formed by a method such as oxidation, chemical vapor deposition, or low-pressure-CVD. It had been. Fumed silica-based abrasives are produced by subjecting silica particles to grain growth by a method such as thermal decomposition of tetrachlorosilicic acid and adjusting the pH. However, such a polishing agent 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.

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 dimensions are further reduced, the technology for narrowing the element separation width is required,
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. Conventional fumed silica abrasives have a small polishing rate ratio of about 3 between the silicon oxide film and the stopper film, and do not have practically usable characteristics for shallow trench isolation.

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.

[0006] Recently, the treatment of industrial waste is becoming a social problem. CMP abrasives are difficult to recycle, and used CMP abrasives are discarded as industrial waste. C
Abrasive particles contained in the MP polishing slurry waste liquid cannot be subjected to sewage treatment as it is and must be separated from waste water. CMP
When additives other than abrasive particles are added to the abrasive, it is desirable to separate the additives from the wastewater, but at present it is poor in simple separation technology.

[0007]

An object of the present invention is to provide a CMP polishing agent capable of polishing a surface to be polished such as a silicon oxide insulating film at a high speed without scratching.
The invention according to claim 2 is, in addition to the invention according to claim 1,
An object of the present invention is to provide a CMP polishing slurry which can easily treat a waste liquid.
A third aspect of the present invention provides a CMP abrasive having improved storage stability in addition to the first or second aspect of the present invention. A fourth aspect of the present invention provides a CMP polishing slurry in which the ratio of the polishing rate of the silicon oxide insulating film to the polishing rate of the silicon nitride insulating film is 10 or more, in addition to the first to third aspects of the present invention. The fifth aspect of the present invention provides a substrate polishing method capable of polishing a surface to be polished of a substrate without damage.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a C-containing cerium oxide particle, a dispersant, a biodegradable additive and water.
It relates to an MP abrasive. The abrasive of the present invention can be composed of a cerium oxide slurry containing cerium oxide particles, a dispersant, and water, and an additive liquid containing a biodegradable additive and water. The additive liquid containing the biodegradable additive is p
It is preferably stored at H10 or higher or pH 5 or lower. The polishing slurry of the present invention preferably has a ratio of the polishing rate of the silicon oxide film to the polishing rate of the silicon nitride film of 10 or more. In the polishing method of the present invention, the substrate on which the film to be polished is pressed against the polishing cloth of the polishing platen is pressed, and the substrate and the polishing platen are supplied while the CMP abrasive is supplied between the polishing film and the polishing cloth. The film to be polished by moving is polished.

[0009]

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. In addition, 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 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.
80) pages 527-532.

[0011] The CMP polishing slurry of the present invention is, for example,
It can be obtained by dispersing a composition comprising cerium oxide particles having the above characteristics, a dispersant, and water, and further adding a biodegradable 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, may be used.

Examples of the water-soluble anionic dispersant include triethanolamine lauryl sulfate, ammonium lauryl sulfate, polyoxyethylene alkyl ether triethanolamine sulfate, and a special polycarboxylic acid type polymer dispersant. Nonionic dispersants include, for example, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene higher alcohol ether, polyoxyethylene octyl phenyl ether, polyoxyethylene Ethylene nonyl phenyl ether, polyoxyalkylene alkyl ether, polyoxyethylene derivative, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan Nopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbate 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, and examples of the water-soluble amphoteric dispersant include lauryl betaine, Allyl betaine, lauryl dimethylamine oxide, 2-alkyl -N- carboxymethyl -N- hydroxyethyl imidazolinium betaine.

The amount of the dispersant added is based on 100 parts by weight of the cerium oxide particles based on 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 dispersant added.
The range is preferably from 0.01 part by weight to 2.0 parts by weight. The molecular weight of the dispersant is preferably from 100 to 50,000, more preferably from 1,000 to 10,000. If 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 if the molecular weight of the dispersant exceeds 50,000, the viscosity is high. This is because the storage stability of the CMP abrasive drops.

As a method for 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 a usual dispersion treatment using a stirrer. The average particle size of the cerium oxide particles in the CMP polishing slurry thus produced is 0.01 μm to
It is preferably 1.0 μm. If the average particle size of the cerium oxide particles is less than 0.01 μm, the polishing rate becomes too low, and if it exceeds 1.0 μm, the film to be polished is easily damaged.

The biodegradable additives include azaserine, asparagine, aspartic acid, 2-aminobutyric acid, 4-aminobutyric acid, alanine, β-alanine, arginine, alloisoleucine, allothreonine, isoleucine, ethionine, Ergothioneine, ornithine, canavanine, S- (carboxymethyl) -cysteine, kynurenine, glycine, glutamine, glutamic acid, creatine, sarcosine, cystathionine, cystine, cysteine, cysteic acid, citrulline, β- (3,4-dihydroxyphenyl) -alanine , 3,5-diiodotyrosine, serine, taurine, thyroxine, tryptophan, threonine, norvaline, norleucine, valine,
One or more amino acids from histidine, 4-hydroxyproline, δ-hydroxylysine, phenylalanine, proline, homoserine, methionine, 1-methylhistidine, 3-methylhistidine, lanthionine, lysine, and leucine Polyamino acids and derivatives thereof, malic acid, tartaric acid, citric acid, isocitric acid, aconitic acid, oxaloacetic acid, glyceric acid,
Water-soluble polyester, polyglyoxylic acid, polyglyoxylate and a water-soluble polyester having one or more kinds of oxycarboxylic acids selected from citramalic acid, desoxalic acid, tetrahydroxysuccinic acid and 3-hydroxyglutaric acid as constituent units Derivatives, pectic acid, alginic acid, chitosan, starch, glycogen, caronine, laminaran, dextran, polysaccharides such as inulin, levan, curdlan, pullulan, polysaccharide derivatives such as carboxymethylcellulose, dextran sulfate, hydroxypropylcellulose, hydroxyethylcellulose Polyethylene glycol, polypropylene glycol, polytetramethylene glycol, alkyl polyethylene glycol,
Alkenyl polyethylene glycol, polyethylene glycol alkyl ether, polyethylene glycol alkenyl ether, alkyl polyethylene glycol alkyl ether, alkyl polyethylene glycol alkenyl ether, alkenyl polyethylene glycol alkyl ether, alkenyl polyethylene glycol alkenyl ether, alkyl polypropylene glycol,
Alkenyl polypropylene glycol, polypropylene glycol alkyl ether, polypropylene glycol alkenyl ether, alkyl polypropylene glycol alkyl ether, alkyl polypropylene glycol alkenyl ether, alkenyl polypropylene glycol alkyl ether, alkenyl polypropylene glycol alkenyl ether (alkyl groups and alkenyl groups each having 1 carbon atom) To 8), polyvinyl alcohol and its derivatives, or a polyvinyl alcohol copolymer containing vinyl alcohol and (A) vinyl formal, vinyl acetal, vinyl amine, vinyl isobutyl ether, vinyl pyrrolidone as components, (B) acrolein , Acrolein whose constituent unit is metaacrolein For the polymer, (C) acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, crotonic acid, isocrotonic acid, 4-pentenoic acid, allylmalonic acid, glutaconic acid, citraconic acid, mesaconic acid, 2-methyl Acrolein-based polymer obtained by graft copolymerization of unsaturated mono- and dicarboxylic acids selected from crotonic acid and 2-methylisocrotonic acid, and a graft copolymer of unsaturated mono- and dicarboxylic acids, and derivatives thereof, (C (D) vinyl alcohol, vinyl acetate, cyclohexenone, cyclopentanone with one or more unsaturated mono- and dicarboxylic acids selected from the group consisting of acrylic acid-based copolymers. Can be used from inside.

The amount of the additive having biodegradability is determined based on the dispersibility and prevention of sedimentation of the particles in the CMP polishing slurry, and further, based on the relationship between polishing scratches and the additive amount, 100 parts by weight of the cerium oxide particles. , 0.01 parts by weight or more, 1,000
A range of not more than parts by weight is preferred. The molecular weight of the biodegradable additive is preferably from 100 to 500,000,
1,000 to 50,000 is preferred. When the molecular weight of the additive 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 additive exceeds 500,000, the viscosity becomes high. This is because the storage stability of the CMP abrasive drops.

When a cerium oxide slurry composed of cerium oxide particles, a dispersant, and water and an additive liquid composed of a biodegradable additive and water are stored as a separate CMP abrasive, the cerium oxide particles do not aggregate, It is preferable because storage stability is increased, polishing scratches are prevented from being generated, and the polishing rate is stabilized. When polishing a substrate with the above-mentioned CMP polishing agent, 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 to polish. The method of supplying on a surface plate is taken.

As the CMP abrasive of the present invention, the above-mentioned CMP abrasive 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.

The additive used for the CMP polishing slurry of the present invention is:
In order to suppress the growth of microorganisms during storage, it is preferable to store at pH 5 or lower or pH 10 or higher. At a pH other than this, microorganisms tend to propagate during storage.

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 surface plate 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 / kg so as not to cause scratches after polishing.
cm 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, 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 flattened in this manner, 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-described 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.

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, Optical glass such as masks, lenses, prisms, etc .; inorganic conductive films such as ITO; optical integrated circuits, optical switching elements, optical waveguides composed of glass and crystalline materials, optical fiber end faces, optical single crystals such as scintillators, solids A laser single crystal, a sapphire substrate for a blue laser LED, a semiconductor single crystal such as SiC, GaP, and GaAs, a glass substrate for a magnetic disk, and a magnetic head can be polished.

[0024]

Next, the present invention will be described by way of examples. Examples and Comparative Examples (Production of cerium oxide particles) 2 kg of cerium carbonate hydrate
Was placed in a platinum container, and calcined at 700 ° 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. Cerium oxide powder was mixed with deionized water so as to have a concentration of 10% by weight, and pulverized at 1400 rpm for 120 minutes using a horizontal wet ultrafine particle dispersion pulverizer.
The obtained polishing liquid was dried at 110 ° C. for 3 hours to obtain cerium oxide particles. The cerium oxide particles have a particle size of 10 nm to 60 nm as observed by a transmission electron microscope.
nm, and the specific surface area measured by the BET method was found to be 39.5 m ² / g. (Preparation of cerium oxide slurry) 125 g of cerium oxide particles prepared by the above method and 3 g of an aqueous solution of polyammonium ammonium salt (40% by weight) having a molecular weight of 10,000 obtained by copolymerizing acrylic acid and methyl acrylate at a ratio of 3: 1 2372 g of deionized water was mixed and ultrasonically dispersed while stirring. Ultrasonic frequency is 40kHz, dispersion time 1
Dispersion was performed at 0 minutes. The obtained slurry was filtered through a 0.8-micron filter, and further, deionized water was added to obtain a 2% by weight cerium oxide slurry (A-1). The pH of the cerium oxide slurry (A-1) was 8.5. When the particle size distribution of the cerium oxide slurry (A-1) was examined with a laser diffraction type particle size distribution analyzer, it was found that the average particle size was as small as 0.20 μm. Also, 1.0
95.0% of particles having a particle size of μm or less. (Preparation of Additive Liquid) To 10 g of ammonium polyaspartate having a molecular weight of 5,000, 990 g of deionized water was added to obtain an additive liquid containing 1% by weight of ammonium polyaspartate. (Polishing of insulating film layer) A silicon oxide film formed by a TEOS-plasma CVD method is formed on a surface plate on which a polishing pad made of a porous urethane resin is bonded, and on a holder on which a suction pad for mounting a substrate is bonded. A 125 mm diameter silicon wafer is set with the insulating film face down, and the polishing load is 3
A weight was placed so as to be 00 g / cm ² . The above-mentioned cerium oxide slurry (solid content: 2% by weight) and the additive liquid were sent onto the platen at a rate of 25 ml / min, and the nozzle was adjusted and dropped so that one liquid was obtained immediately before the platen. The platen was rotated at 40 rpm for 2 minutes to polish the insulating film. After polishing, the wafer was removed from the holder, washed well with running water, and further washed with an ultrasonic cleaner for 20 minutes. After washing, water droplets were removed with a spin drier and dried with a dryer at 120 ° C. for 10 minutes. The change in film thickness before and after polishing was measured using an optical interference type film thickness measuring device, and the polishing rate was calculated. Similarly, instead of a silicon oxide film formed by the TEOS-plasma CVD method, a silicon nitride film formed by a low-pressure CVD method was polished under the same conditions, a change in film thickness before and after polishing was measured, and a polishing rate was calculated. Also, from the results of the film thickness measurement,
It was found that the silicon oxide film formed by the TEOS-plasma CVD method and the silicon nitride film formed by the low-pressure CVD method had a uniform thickness over the entire surface of the wafer. Also,
No damage was found on the insulating film surface by visual observation under the light source of a mercury lamp. (Evaluation of biodegradability)
Performed according to K 6950. Activated sludge suspension 20 in a glass culture bottle (300 ml) equipped with a burette
0 ml, inorganic salt solution 0.8 ml (K ₂ HPO ₄ 0.46
_{%, Na 2 HPO 4 · 12H} 2 O1.16%, MgSO
_{4 · 7H 2 O 0.05%,} FeCl 3 · 6H 2 O
0.01%, CaCl ₂ .2H ₂ O 0.005%, N
H ₄ Cl 0.1%) and about 1 ml of the sample solution were added, and a decomposition test was performed at 25 ° C. using a BOD measuring device equipped with a thermostat. The BOD (biochemical oxygen consumption) was measured over time for about 28 days. BO due to fluctuations in atmospheric pressure
A value obtained by subtracting a blank test value to correct a change in the D value was defined as a true BOD value. The degree of biodegradation was calculated as (true BOD value) / (theoretical oxygen consumption) x 100. (Measurement of viable cell count) The diluted additive solution was applied on an agar medium which had been solidified in advance, and the mixture was added at 30 ° C for 24 to 48 hours.
After culturing for an hour, the number of generated colonies was measured. As shown in Table 1, a cerium oxide slurry and an additive solution were prepared to prepare a CMP abrasive, and the insulating film layer was polished. Table 1 shows the results. As is evident from Table 1, the additives contained in the CMP polishing slurry according to the present invention have good preservability before use and easy waste liquid treatment after use.
Further, by using the CMP polishing slurry and the substrate polishing method of the present invention, the substrate can be polished without being damaged, and the ratio of the polishing rate of the silicon oxide film / the polishing rate of the silicon nitride film is set to 10 or more. It can be seen that a CMP abrasive and a method for polishing a substrate using these CMP abrasives can be obtained.

[0025]

[Table 1]

[0026]

According to the present invention, the surface to be polished such as the silicon oxide insulating film according to the first aspect can be polished at high speed without being damaged, and is suitable for a polishing method used in semiconductor device manufacturing technology. The CMP polishing slurry according to claim 2 has the effect according to claim 1,
Furthermore, the point that waste liquid treatment is easy is excellent. The CMP abrasive according to claim 3 has the effect according to claim 2, and furthermore,
Excellent storage stability is excellent. The CM according to claim 4
The P polishing agent has the effect of claim 3 and further has a ratio of the polishing rate of the silicon oxide insulating film to the polishing rate of the silicon nitride insulating film of 1
It is suitable for shallow trench isolation because it is 0 or more. The method for polishing a substrate according to the fifth aspect is excellent in polishing the surface to be polished of the substrate without being damaged, and is suitable for a polishing method used in a semiconductor device manufacturing technique.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Masato Yoshida 48 Wadai, Tsukuba, Ibaraki Prefecture F-term in Tsukuba Development Laboratory, Hitachi Chemical Co., Ltd. 3C058 AA07 CB02 CB03 CB04 CB10 DA02 DA12 DA17 4G076 AA02 AB09 AC04 BA39 BC08 BD01 BG06 CA26 CA28 DA30

Claims (5)

[Claims] 1. A CMP polishing slurry containing cerium oxide particles, a dispersant, a biodegradable additive and 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 liquid containing a biodegradable additive and water. 3. An additive liquid containing a biodegradable additive,
The CMP polishing slurry according to claim 2, which is stored at a pH of 10 or more or 5 or less. 4. The CMP polishing slurry according to claim 1, wherein a ratio of a polishing rate of the silicon oxide film to a polishing rate of the silicon nitride film is 10 or more. 5. The CMP according to claim 1, wherein the substrate on which the film to be polished is formed is pressed against a polishing cloth of a polishing platen and pressurized.
A substrate polishing method for polishing a film to be polished by moving a substrate and a polishing plate while supplying an abrasive between the polishing film and the polishing cloth.