JP5481166B2 - Slurries for chemical mechanical polishing - Google Patents

Description

  The present invention relates to a slurry for chemical mechanical polishing suitable for manufacturing a semiconductor substrate, and a method for polishing and manufacturing a substrate using the slurry.

  Higher performance of semiconductor circuits is achieved by miniaturizing transistors, resistors, wirings, etc. that make up circuits, and by increasing the density and speeding up response at the same time. High density and high integration became possible. As a technology in semiconductor manufacturing that makes these possible, there are shallow trench isolation (shallow trench isolation), metal plug, and damascene method. “Shallow trench isolation” means transistor element isolation, metal plug means three-dimensional wiring with metal having a structure penetrating an interlayer insulating film, and “damascene method” means copper wiring embedding technology. A technique essential to each process such as shallow trench isolation is chemical mechanical polishing (CMP). “CMP” is an abbreviation for Chemical Mechanical Polishing, and is always used in each process of shallow trench isolation, damascene method, interlayer insulating film formation, and metal plug embedding. These fine patterns are formed by transferring a resist mask formed by a photolithography process. However, as the miniaturization progresses, the depth of focus of the projection lens used for lithography becomes shallower, and the unevenness of the substrate is within that range. Since it must be accommodated, the required flatness is increased. By flattening the processed surface by CMP, a flat surface at the nano-order and atomic level can be obtained, and high performance can be achieved by three-dimensional wiring, that is, lamination. CMP is currently introduced when performing planarization of an interlayer insulating film, BPSG film (silicon oxide film doped with boron, phosphorus, etc.), shallow trench isolation formation, plug and buried metal wiring formation, and the like.

  In shallow trench isolation, CMP is used to remove an extra insulating film made of silicon oxide or the like formed on a substrate, and a stopper film is formed under the insulating film to stop polishing. . As the stopper film, silicon nitride or the like is generally used. By increasing the polishing rate ratio between the insulating film and the stopper film, it becomes easy to set the polishing end point. It is desirable to eliminate the step and obtain a flat polished film after polishing. Further, in order to obtain a flat film to be polished, it is desirable that polishing is stopped on the stopper film and polishing of the insulating film and the stopper film does not proceed at the time of excessive polishing after the step is eliminated.

  Conventionally, water-soluble organic compounds such as polyacrylic acid and its salts to improve the stability of abrasive grains in chemical mechanical polishing slurries, control the polishing rate, improve flatness, eliminate steps, and suppress polishing during excessive polishing. Is known to be added to a chemical mechanical polishing slurry (see Patent Document 1 and Patent Document 2).

  Also known is a system in which a carboxylic acid polymer such as polyacrylic acid or a salt thereof, and polyvinylpyrrolidone, a cationic compound, or a zwitterionic compound are used in combination (see Patent Document 3).

  Furthermore, in metal film polishing in the damascene method, cyclic compounds having a pyranose skeleton such as D-ribose and D-arabinose, cyclic compounds having a furanose skeleton such as D-fructose and D-erythrose, glucose such as cyclodextrin Chemical mechanical polishing slurries in which a compound having a skeleton, an organic acid, and the like are blended are known (see Patent Documents 4 to 6).

Japanese Patent No. 3672493 Japanese Patent No. 3649279 JP 2007-27397A Japanese Patent Laid-Open No. 11-246851 JP 2002-110596 A JP 2006-066874 A

  However, the slurry for chemical mechanical polishing containing water-soluble organic compounds such as polyacrylic acid and salts thereof described in Patent Documents 1 to 3, or the slurry for chemical mechanical polishing further using polyvinylpyrrolidone or the like is used. In terms of reducing the level difference between the insulating film and the stopper film, it is not always satisfactory. Further, in the chemical mechanical polishing slurries described in Patent Documents 4 to 6, there is no suggestion about reducing the step between the insulating film and the stopper film. In the chemical mechanical polishing slurry, the step between the insulating film and the stopper film could not be made sufficiently small.

  Therefore, the present invention provides a chemical mechanical polishing slurry capable of extremely reducing the level difference between an insulating film formed of silicon oxide or the like and a stopper film formed of silicon nitride or the like in a shallow trench isolation process. And it aims at providing the grinding | polishing and manufacturing method of a board | substrate.

  As a result of intensive studies to solve the above problems, the present inventors use a water-soluble clathrate compound (a) having a specific molecular weight together with abrasive grains (b) at a specific content. Thus, in the shallow trench isolation process, it has been found that a film to be polished having a very small step between the insulating film and the stopper film can be obtained, and the present invention has been completed.

That is, the present invention relates to the following [1] to [11].
[1] A slurry for chemical mechanical polishing containing a water-soluble clathrate compound (a), abrasive grains (b) and water (c), wherein the water-soluble clathrate compound (a) is 200-1 For chemical mechanical polishing for shallow trench isolation process, having a weight average molecular weight of 1,000,000 and containing in the range of more than 0.5% by weight and not more than 10% by weight with respect to the total amount of slurry slurry.
[2] The slurry for chemical mechanical polishing according to [1] above, wherein the water-soluble inclusion compound (a) is one or more selected from the group consisting of cyclic oligosaccharides and derivatives thereof.
[3] The slurry for chemical mechanical polishing according to the above [2], wherein the cyclic oligosaccharide and its derivative are α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and derivatives thereof.
[4] The slurry for chemical mechanical polishing according to [1] above, wherein the water-soluble clathrate compound (a) is contained in an amount of 0.6% by mass to 5% by mass with respect to the total amount of the slurry.
[5] The slurry for chemical mechanical polishing according to the above [1], wherein the polishing abrasive grains (b) are inorganic oxide particles having an average particle diameter of 0.5 nm to 1,000 nm.
[6] The slurry for chemical mechanical polishing according to the above [1], wherein the polishing abrasive grains (b) are contained in an amount of 0.1% by mass to 30% by mass with respect to the total amount of the slurry.
[7] One or more inorganic oxide particles selected from the group consisting of aluminum oxide, cerium oxide, fumed silica, zirconium oxide, titanium oxide, tin oxide, germanium oxide, magnesium oxide and manganese oxide The slurry for chemical mechanical polishing according to [5] above, which is a particle.
[8] The slurry for chemical mechanical polishing according to any one of [1] to [7], wherein the pH is 3 to 12.5.
[9] While supplying the chemical mechanical polishing slurry according to any one of [1] to [8] between the substrate and the polishing pad, the substrate and the polishing pad are relatively moved to insulate the substrate. A method for polishing a substrate, comprising polishing a film.
[10] Insulation on the substrate by relatively moving the substrate and the polishing pad while supplying the chemical mechanical polishing slurry according to any one of [1] to [8] between the substrate and the polishing pad. A method for manufacturing a substrate, comprising a step of polishing a film.
[11] The method according to [9] or [10] above, wherein the insulating film on the substrate is a silicon oxide film and / or a silicon nitride film.

  The slurry for chemical mechanical polishing according to the present invention can provide a film to be polished having a very small step between the insulating film and the stopper film in the polishing process of the insulating film and the interlayer insulating film in shallow trench isolation. The yield of time can be improved.

  The slurry for chemical mechanical polishing of the present invention contains a water-soluble clathrate compound (a), abrasive grains (b) and water (c). In the present invention, a water-soluble clathrate compound having a weight average molecular weight of 200 to 1,000,000 is used as the water-soluble clathrate compound (a).

  In the present invention, examples of the “water-soluble clathrate compound” include compounds having a solubility in water at 25 ° C. of 0.01 g / L or more and having a cyclic structure. When the solubility in water at 25 ° C. is less than 0.01 g / L, the effect of reducing the step between the insulating film and the stopper film and suppressing the polishing rate at the time of excessive polishing cannot be obtained. In order to satisfactorily reduce the step and excessive polishing when added to the polishing slurry, the solubility in water at 25 ° C. is preferably 0.1 g / L or more, and 0.5 g / L or more is more preferable.

  The “inclusion compound” is a generic name for a compound having a cavity and capable of incorporating another molecule (guest) into the molecule (host). As host compounds, cylindrical and cyclic compounds such as cyclodextrin and crown ether are well known. These compounds are known to be able to control the size of guest molecules to be incorporated depending on the size of the cavity.

  The water-soluble clathrate compound preferably has a weight average molecular weight of 200 to 1,000,000. If the molecular weight is less than 200, the level difference between the insulating film and the stopper film is not reduced. If the molecular weight exceeds 1,000,000, the viscosity of the chemical mechanical polishing slurry increases, and chemical mechanical polishing during polishing is performed. Since the slurry inflow property is reduced, the polishing uniformity is reduced. In order to obtain a good working effect as a slurry for chemical mechanical polishing, the weight average molecular weight of the water-soluble clathrate compound is more preferably in the range of 500 to 900,000, and in the range of 700 to 800,000. More preferably it is. The weight average molecular weight is measured by connecting a GPC column (“GMPWXL” manufactured by Tosoh Corporation) to a GPC apparatus (“150C” manufactured by Waters), using a 200 mM phosphate aqueous solution as a mobile phase, Values converted and used are used.

  Examples of the water-soluble inclusion compound include cyclic oligosaccharides and derivatives thereof, water-soluble porphyrins, water-soluble phthalocyanines, crown ethers, water-soluble cyclophanes, water-soluble calixarenes, and the like. As the water-soluble inclusion compound, cyclic oligosaccharides and derivatives thereof are preferable from the viewpoint of industrial availability.

  One of these cyclic oligosaccharides and derivatives thereof may be selected from these and used alone, or two or more may be selected and used in combination.

  In the present invention, the “cyclic oligosaccharide and its derivative” include a compound obtained by cyclizing a monosaccharide having a pyranose skeleton and / or a furanose skeleton at 5 or more and 20 or less regardless of the bonding position, or a derivative thereof. Is mentioned.

  A monosaccharide having a pyranose skeleton and / or a furanose skeleton can be used regardless of the stereoisomer of D-form or L-form. Monosaccharides having a pyranose skeleton include allose, talose, growth, glucose, altrose, mannose, galactose, idose, rhamnose, etc. Monosaccharides having a furanose skeleton include erythrose, threose, ribose, lyxose, xylose, arabinose, etc. Is mentioned.

  Examples of suitable cyclic oligosaccharides and derivatives thereof include cyclodextrin, cyclomannin, cycloawadolin, and derivatives thereof. From the viewpoint of industrial availability, etc., α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and derivatives thereof are preferable. From the viewpoint of water solubility, α-cyclodextrin and derivatives thereof, β-cyclodextrin are preferable. Dextrin derivatives and γ-cyclodextrin and its derivatives are more preferred.

  Examples of the derivative of the cyclic oligosaccharide include a carboxyl group or a hydroxyl group of the cyclic oligosaccharide, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, etc. Derivatives into which a linear or branched alkyl group having 1 to 20 carbon atoms is introduced, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, etc. Dicarboxylic acids such as monocarboxylic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, tartaric acid, citric acid Derivatives in which compounds having hydroxycarboxylic acid such as acid and isocitric acid are introduced And the like.

  The water-soluble clathrate compound needs to be contained in the range of more than 0.5% by mass and 10% by mass or less with respect to the total amount of the slurry. If the content of the water-soluble clathrate compound is 0.5% by mass or less with respect to the total amount of the slurry, the water-soluble compound is not sufficiently adsorbed to the substrate, so that the step between the insulating film and the stopper film Is not solved, and polishing during excessive polishing proceeds. On the other hand, when the water-soluble clathrate compound is contained in an amount exceeding 10% by mass with respect to the total amount of the slurry, the water-soluble clathrate compound is excessively adsorbed on the substrate, and the polishing rate is reduced. The abrasive grains in the chemical mechanical polishing slurry tend to agglomerate. From the viewpoints of eliminating the step difference between the insulating film and the stopper film, suppressing the polishing rate at the time of excessive polishing, and suppressing aggregation of abrasive grains in the slurry for chemical mechanical polishing, the content of the water-soluble clathrate compound is More preferably, the content is 0.6% by mass to 5% by mass, and further preferably 0.6% by mass to 3.5% by mass with respect to the total amount of the slurry.

  The abrasive grains (b) used in the present invention are preferably fine particles having an average particle diameter of 0.5 nm to 1,000 nm. When the average particle size of the abrasive grains is less than 0.5 nm, the polishing rate may decrease. When the average particle size exceeds 1,000 nm, polishing flaws tend to occur. From the viewpoint of suppressing the polishing rate and suppressing the generation of polishing flaws, the average particle size of the abrasive grains is more preferably 1 nm to 700 nm, and further preferably 5 nm to 500 nm.

  The average particle size of the abrasive grains can be measured by a dynamic light scattering method using a particle size measuring device (such as “Zeta potential / particle size measuring system ELSZ-2” manufactured by Otsuka Electronics Co., Ltd.).

  As said abrasive grain, an organic compound, a high molecular compound, an inorganic compound, and an organic-inorganic composite material can be used, for example.

  Although it does not specifically limit as said organic compound and a high molecular compound, For example, an unsaturated double bond, such as a fullerene derivative, a polystyrene particle, a polyethylene particle, a polyacrylic acid particle, a polymethacrylic acid particle, a polyacrylamide particle, a polymethacrylamide particle And a polymer compound obtained by polymerizing monomers having a single or a combination of plural monomers.

  Examples of the inorganic compound include fullerene, nanodiamond, silicon, germanium, silicon oxide, germanium oxide, metal, metal oxide, metal sulfide, metal chloride, metal carbonate, metal sulfate, metal nitrate, and metal fluoride. And metal compounds such as metal bromide, metal nitride and metal iodide, and compound semiconductors such as gallium arsenide, zinc selenide and cadmium telluride. Examples of the metal and metal of the metal compound include lithium, sodium, potassium, magnesium, calcium, aluminum, gallium, indium, zinc, cadmium, copper, silver, gold, nickel, palladium, cobalt, rhodium, iron, manganese, chromium, Molybdenum, tungsten, vanadium, niobium, tantalum, titanium, cerium, lanthanum, yttrium, iridium, zirconium, tin, and the like can be mentioned, and these can be used alone or in combination.

  Examples of the organic-inorganic composite material include, for example, an inorganic compound particle coated with an organic compound, an organic compound particle coated with an inorganic compound, an organic compound particle dispersed with an inorganic compound particle, an organic polysiloxane compound, etc. Is mentioned.

  From the viewpoint of polishing efficiency, it is preferable to use particles of the above-mentioned inorganic compound as the abrasive grains. Among the inorganic compound particles, from the viewpoint of high polishing rate and excellent polishing scratch reduction, aluminum oxide, cerium oxide, fumed silica, zirconium oxide, titanium oxide, tin oxide, germanium oxide, magnesium oxide, oxidation Each particle of manganese is more preferable, and cerium oxide particles are more preferable.

  The content of the abrasive grains (b) is preferably 0.1% by mass to 30% by mass, more preferably 0.2% by mass to 25% by mass with respect to the total amount of the slurry, and 0.3 It is especially preferable that it is mass%-20 mass%. When the content is less than 0.1% by mass, the polishing rate tends to decrease, and when it exceeds 30% by mass, the abrasive grains tend to aggregate.

  In order to improve the dispersion stability of the abrasive grains, the chemical mechanical polishing slurry of the present invention may contain a known dispersant as long as the characteristics of the present invention are not impaired.

  Examples of the dispersant include a water-soluble anionic dispersant, a water-soluble nonionic dispersant, a water-soluble cationic dispersant, and a water-soluble zwitterionic dispersant. Examples of the water-soluble anionic dispersant include polyacrylic acid, polymethacrylic acid, polystyrene sulfonic acid, polysulfonic acid and the like, and salts thereof. Examples of the water-soluble nonionic dispersant include water-soluble cationic dispersants such as polyvinyl alcohol, polyvinyl butyral, polyethylene glycol, polyvinyl pyrrolidone, polyacrylamide, polymethacrylamide, N-substituted polyacrylamide, and N, N-substituted polyacrylamide. Examples thereof include polyethyleneimine and polyallylamine. Examples of the water-soluble zwitterionic dispersant include a copolymer obtained by copolymerizing a monomer having a cationic and an anionic unsaturated double bond, a betaine having an anion and a cation at each end. . In the present invention, one or more of these dispersants can be selected and used.

  The slurry for chemical mechanical polishing of the present invention includes an anionic polymer compound, a nonionic polymer compound, a cationic polymer compound, a zwitterionic polymer compound, and a polysaccharide as long as the characteristics of the present invention are not impaired. May be included. Examples of the anionic polymer compound include polyacrylic acid, polymethacrylic acid, polystyrene sulfonic acid, polysulfonic acid, and salts thereof, and examples of the nonionic polymer compound include polyvinyl alcohol, polyvinyl butyral, polyethylene, and the like. Glycol, polyvinyl pyrrolidone, polyacrylamide, polymethacrylamide, N-substituted polyacrylamide, N, N-substituted polyacrylamide, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, etc. Is mentioned. Examples of the cationic polymer compound include polyethyleneimine, polyallylamine, and the like. As the zwitterionic polymer compound, monomers having cationic and anionic unsaturated double bonds are copolymerized. And a betaine having an anion and a cation at each end. Examples of the polysaccharide include dextran, glycogen, amylose, amylopectin, heparin, and agarose.

  Furthermore, the chemical mechanical polishing slurry of the present invention may contain a low molecular compound having a molecular weight of 10 to 1,000 within a range not impairing the characteristics of the present invention. Such low molecular weight compounds include amines such as ethylamine, diethylamine, triethylamine, pyridine, piperazine, imidazole, butylamine, dibutylamine, isopropylamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, and aminoethylethanolamine. Alcohols such as methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol; formic acid, acetic acid, butyric acid, propionic acid, malonic acid, succinic acid, fumaric acid, maleic acid, phthalic acid, salicylic acid, acrylic acid, Carboxylic acids such as methacrylic acid; amino acids such as glycine, alanine, phenylalanine, glutamic acid, aspartic acid, histidine; dioxane, dimethyl ether, diethyl ether, methyl ethyl ether, etc. Ethers; ketones such as acetone, diethyl ketone, and methyl ethyl ketone; oxidizing agents such as hydrogen peroxide and ammonium persulfate; and complexing agents such as benzotriazole and thiabendazole.

  In the present invention, water (c) is not particularly limited, and distilled water, deionized water and the like can be preferably used.

  The chemical mechanical polishing slurry of the present invention is preferably used for polishing after adjusting to a desired pH. As a pH adjuster, when used for semiconductor polishing, it is preferable to use an acid component such as aqueous ammonia or hydrochloric acid rather than an alkali metal hydroxide in order to prevent metal contamination. The pH of the chemical mechanical polishing slurry of the present invention is preferably 3 to 12.5. When the pH of the slurry for chemical mechanical polishing is less than 3, the polishing rate decreases, and when it exceeds 12.5, the flatness of the insulating film on the substrate tends to decrease. From the viewpoint of polishing rate and flatness of the insulating film on the substrate, the pH of the chemical mechanical polishing slurry of the present invention is more preferably 3.3 to 12, and preferably 3.5 to 11.7. Is more preferable.

  In the present invention, the pH of the chemical mechanical polishing slurry can be measured according to a usual method using, for example, a pH meter (such as “pH meter F22” manufactured by Horiba, Ltd.).

  The chemical mechanical polishing slurry of the present invention is prepared and stored as a two-component chemical mechanical polishing slurry comprising, for example, a slurry containing polishing abrasive grains and a water-soluble clathrate aqueous solution. Alternatively, it may be prepared and stored in advance as a one-component chemical mechanical polishing slurry in which a slurry containing abrasive grains and a water-soluble clathrate aqueous solution are mixed. In addition, what is necessary is just to mix at the time of grinding | polishing and to make 1 liquid, when preparing as 2 liquid systems. When preparing as a two-component polishing slurry, the flatness and polishing rate of the insulating film to be polished, and the step elimination performance can be easily adjusted by arbitrarily changing the blend of these two solutions at the time of use. When polishing using a two-component chemical mechanical polishing slurry, for example, a slurry containing abrasive grains and a water-soluble clathrate aqueous solution are fed through separate pipes, and these pipes are joined together. For example, a method in which the slurry is mixed immediately before the supply pipe outlet and supplied onto the polishing pad, or a method in which the slurry containing the abrasive grains and the water-soluble clathrate aqueous solution are mixed immediately before the polishing is used. Furthermore, when mixing the slurry containing abrasive grains and the water-soluble clathrate aqueous solution in the pipe or just before polishing as described above, water is mixed as necessary to adjust the polishing characteristics. You can also.

  In the polishing method of the present invention, the chemical mechanical of the present invention is applied by pressing a substrate on which a film to be polished is pressed against a polishing pad affixed on a polishing surface plate using a double-sided tape, a surface fastener, or the like. The polishing target film is polished by relatively moving the substrate and the polishing pad while supplying the polishing slurry between the substrate and the polishing pad.

  Examples of the substrate include semiconductor substrates such as silicon, germanium, zinc selenide, cadmium sulfide, zinc oxide, gallium arsenide, indium phosphide, gallium nitride, and silicon carbide. Examples of the film to be polished on the substrate include an insulating film layer formed from a silicon oxide film or the like and a stopper film formed from a silicon nitride film or the like. By polishing the silicon oxide film layer, the silicon nitride film layer, etc. formed on such a semiconductor substrate with a slurry for chemical mechanical polishing, the unevenness of the substrate surface is eliminated, and there is no level difference over the entire surface of the substrate. It can be a surface.

  In the polishing method of the present invention, as an apparatus used for polishing, for example, a polishing platen to which a polishing pad can be attached and a motor capable of changing the number of revolutions is attached, and a substrate having a film to be polished A general polishing apparatus or the like having a holder that can hold the substrate can be used.

  The polishing conditions are not particularly limited, but for efficient polishing, the rotation speed of each of the surface plate and the substrate is preferably a low rotation of 300 rpm or less, and the pressure applied to the substrate is set so that scratches do not occur after polishing. From the standpoint of performing, it is preferably set to 150 kPa or less. During polishing, it is preferable to continuously supply chemical mechanical polishing slurry to the polishing pad with 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 for chemical mechanical polishing.

  After the polishing, the semiconductor substrate is preferably thoroughly washed in running water, and then dried by removing water droplets adhering to the semiconductor substrate using a spin dryer or the like. As described above, by polishing the inorganic insulating film layer, which is a film to be polished, with the above-mentioned slurry for chemical mechanical polishing, unevenness on the surface of the insulating film can be eliminated, and a smooth surface can be obtained over the entire surface of the semiconductor substrate. After forming the flattened shallow trench in this way, aluminum wiring or copper wiring is formed on the inorganic insulating film layer, and an inorganic insulating film is formed between and on the wiring by a method described later. After that, polishing is similarly performed using a chemical mechanical polishing slurry to obtain a smooth surface. By repeating this step a predetermined number of times, a semiconductor substrate having a desired number of layers can be manufactured.

  Although it does not restrict | limit especially as a polishing pad which can be used in this invention, For example, a general nonwoven fabric, a woven fabric, artificial leather, a synthetic resin etc. are mentioned. Of these, synthetic resins are preferably used.

  Examples of the synthetic resin include thermosetting polyurethane resin; thermoplastic polyurethane resin; epoxy resin; fluororesin; polyolefin resin such as polyethylene resin and polypropylene resin; crosslinked rubber such as polybutadiene resin and polystyrene butadiene resin; Examples include acrylic resins such as polymethacrylic acid resin and polymethyl methacrylate resin; vinyl resins such as polyvinyl alcohol resin, polyvinyl butyral resin, and ethylene-vinyl acetate copolymer resin. The synthetic resin may be used alone, or may be used in combination of two or more kinds, and may further be used with additives. From the viewpoint of wear resistance, polyurethane resin is preferable.

  The synthetic resin is not particularly limited, but may be a porous body. As a method for producing a porous body, for example, a method of dispersing a minute hollow body in a synthetic resin, a water-soluble polymer compound alone, or a combination of a plurality of types in a synthetic resin, the chemicals during polishing can be used. The water-soluble polymer compound is eluted with a slurry for mechanical mechanical polishing to form a substantially porous body, a method using supercritical foam molding, and polymer compound fine particles are sintered to form a continuous pore structure And the like.

  The structure of the polishing pad is not particularly limited, and may be a single layer structure or a multilayer structure having a cushion layer. Moreover, it is preferable that the polishing pad is subjected to a process of adding a hole structure and / or a groove structure so that a slurry for chemical mechanical polishing is accumulated. The groove structure is not particularly limited, but a lattice, radial, spiral, concentric groove, or the like can be used. The groove structure and the hole structure can be used alone or in combination. Furthermore, the polishing pad may have a structure in which abrasive grains are included in the polishing pad. In order to encapsulate the abrasive grains in the polishing pad, for example, a method of mixing abrasive grains, synthetic resin and solvent, injecting the mixture into a mold and then drying, mixing abrasive grains with molten synthetic resin, and mixing the mixture A method of cooling after pouring into a mold can be used.

  In the polishing method of the present invention, if necessary, a conditioner for CMP in which diamond particles are fixed to the surface of the carrier by nickel electrodeposition or the like is attached to a polishing apparatus, and the conditioner is pressed onto the polishing pad, and the surface of the polishing pad Can be adjusted to a surface roughness suitable for polishing an insulating film as a film to be polished.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all by these Examples.

[Example 1] Preparation of slurry for chemical mechanical polishing 50 g of cerium oxide abrasive grains (abrasive “GPL-C1010” (stock solution concentration: 10% by mass) manufactured by Showa Denko KK), α-cyclodextrin (Wako Pure Chemical Industries, Ltd.) 9.0 g, distilled water was mixed in a 1 L graduated cylinder and 28% by mass ammonia water (manufactured by Wako Pure Chemical Industries, Ltd.) was added while stirring with a magnetic stirrer, resulting in a pH of 8.1. Then, the total amount was made 1,000 g with distilled water to obtain a slurry for chemical mechanical polishing having an abrasive concentration of 0.5 mass% and an α-cyclodextrin concentration of 0.9 mass%.

[Example 2] Preparation of slurry for chemical mechanical polishing Except that the addition amount of α-cyclodextrin (manufactured by Wako Pure Chemical Industries, Ltd.) was 6.0 g and the concentration of α-cyclodextrin was 0.6% by mass. A slurry for chemical mechanical polishing was prepared in the same manner as in Example 1.

[Example 3] Preparation of slurry for chemical mechanical polishing 9.0 g of γ-cyclodextrin (manufactured by Wako Pure Chemical Industries, Ltd.) was added instead of α-cyclodextrin, and the concentration of γ-cyclodextrin was adjusted to 0.9. A slurry for chemical mechanical polishing was prepared in the same manner as in Example 1 except that the mass% was used.

[Example 4] Preparation of slurry for chemical mechanical polishing In place of α-cyclodextrin, 9.0 g of methyl-β-cyclodextrin (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the concentration of methyl-β-cyclodextrin was increased. A slurry for chemical mechanical polishing was prepared in the same manner as in Example 1 except that the amount was 0.9 mass%.

[Example 5] Preparation of slurry for chemical mechanical polishing In place of α-cyclodextrin, 9.0 g of β-cyclodextrin (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the β-cyclodextrin concentration was adjusted to 0.9. A slurry for chemical mechanical polishing was prepared in the same manner as in Example 1 except that the mass% was used.

[Example 6] Preparation of slurry for chemical mechanical polishing Except that the addition amount of α-cyclodextrin (manufactured by Wako Pure Chemical Industries, Ltd.) was 15.0 g and the α-cyclodextrin concentration was 1.5% by mass. A slurry for chemical mechanical polishing was prepared in the same manner as in Example 1.

[Comparative Example 1] Preparation of slurry for chemical mechanical polishing Except that 9.0 g of dextran (manufactured by Wako Pure Chemical Industries, Ltd.) was added instead of α-cyclodextrin, and the dextran concentration was adjusted to 0.9 mass%. A slurry for chemical mechanical polishing was prepared in the same manner as in Example 1.

[Comparative Example 2] Preparation of slurry for chemical mechanical polishing Except that 9.0 g of sucrose (manufactured by Wako Pure Chemical Industries, Ltd.) was added instead of α-cyclodextrin, and the sucrose concentration was 0.9 mass%. A slurry for chemical mechanical polishing was prepared in the same manner as in Example 1.

[Comparative Example 3] Preparation of slurry for chemical mechanical polishing In place of α-cyclodextrin, 4.0 g of polyacrylic acid (Wako Pure Chemical Industries, Ltd., weight average molecular weight 5,000) was added, and polyacrylic acid was added. A slurry for chemical mechanical polishing was prepared in the same manner as in Example 1 except that the concentration was 0.4 mass% and the pH was adjusted to 5.0.

[Comparative Example 4] Preparation of slurry for chemical mechanical polishing Instead of α-cyclodextrin, 4.0 g of polyacrylic acid (manufactured by Wako Pure Chemical Industries, Ltd., weight average molecular weight 25,000) was added, and polyacrylic acid was added. A slurry for chemical mechanical polishing was prepared in the same manner as in Example 1 except that the concentration was 0.4 mass% and the pH was adjusted to 5.0.

[Comparative Example 5] Preparation of slurry for chemical mechanical polishing 4.0 g of polyacrylic acid (manufactured by Wako Pure Chemical Industries, Ltd., weight average molecular weight 250,000) was added instead of α-cyclodextrin, and polyacrylic acid was added. A slurry for chemical mechanical polishing was prepared in the same manner as in Example 1 except that the concentration was 0.4 mass% and the pH was adjusted to 5.0.

[Comparative Example 6] Preparation of slurry for chemical mechanical polishing Except that the addition amount of α-cyclodextrin (manufactured by Wako Pure Chemical Industries, Ltd.) was 1.0 g and the α-cyclodextrin concentration was 0.1% by mass. A slurry for chemical mechanical polishing was prepared in the same manner as in Example 1.

  For the abrasive grains (b) used in the chemical mechanical polishing slurries of the above Examples and Comparative Examples, the average particle diameter was measured. Moreover, pH was measured about each chemical mechanical polishing slurry, the insulating film layer was grind | polished using these, and the level | step difference measurement of an insulating film and a stopper film was performed. The method for measuring the average particle diameter of the abrasive grains (b), the method for measuring the pH of the slurry for chemical mechanical polishing, the method for polishing the insulating film layer and measuring the step between the insulating film and the stopper film are shown below. It was.

[Measurement of average particle diameter of abrasive grains (b)]
About slurry for chemical mechanical polishing, “Zeta potential / particle size measurement system ELSZ-2” manufactured by Otsuka Electronics Co., Ltd., 25 ° C., pinhole diameter 50 μm, solvent condition; refractive index of water at 25 ° C. = 1. The measurement was performed twice under the conditions of 33, viscosity = 0.89 cP, and relative dielectric constant = 78.3, and the average particle size and particle size distribution were determined by cumulant analysis, and the average particle size was averaged.

  When the cerium oxide abrasive liquid 10% by mass (abrasive “GPL-C1010” manufactured by Showa Denko KK (stock concentration 10% by mass)) was measured, the average particle size was 197.1 nm.

[Measurement of pH]
Using “pH meter F22” manufactured by HORIBA, Ltd., standard buffer solution (phthalate pH buffer solution: pH 4.00 (25 ° C.), neutral phosphate pH buffer solution: pH 7.00 (25 ° C.), boric acid After calibrating three points using a salt pH buffer solution (pH 9.00 (25 ° C.)), the electrode was placed in a chemical mechanical polishing slurry, and the value after 2 minutes had elapsed and stabilized was measured. .

[Insulating film layer polishing]
A pattern wafer “SKW3-2” manufactured by SKW was used as a test wafer for shallow trench element isolation insulating film CMP evaluation. The wafer was fixed to a wafer holding part of a polishing apparatus (“BC-15” manufactured by MAT). On the other hand, a polishing pad of 380 mmΦ (“IC1400” concentric groove made by Rohm & Haas) was attached to the polishing surface plate with a double-sided tape. Using a conditioner (made by Allied Material Co., Ltd., diameter: 19.0 cm), rotating in the same direction at pressure = 3.48 kPa, surface plate rotation speed = 100 rpm, conditioner rotation speed = 140 rpm, the deionized water was pumped in a fixed amount (Tokyo) The polishing pad was conditioned for 60 minutes while being supplied at a flow rate of 150 mL per minute using “RP-1000” manufactured by Rika Kikai Co., Ltd. While supplying the chemical mechanical polishing slurries of Examples and Comparative Examples at a flow rate of 120 mL per minute on the polishing pad, the polishing platen was rotated in the same direction at 100 rpm and the wafer at 99 rpm. The wafer was pressed onto the polishing pad at a load of 23.4 kPa, and the shallow trench isolation insulating film CMP evaluation test wafer was polished. The point at which the silicon oxide film on the convex silicon nitride film disappears and the silicon nitride film is exposed is referred to as “just polishing”, the wafer is washed with distilled water, dried, and an optical interference type film thickness measuring device (manufactured by Nanometrics “ Nano spec AFT Model 5100 ") was used to measure the film thickness of silicon oxide and silicon nitride. For the level difference, a surface roughness measuring machine (small surface roughness measuring machine “SJ-400” manufactured by Mitutoyo Corporation) is used, a standard stylus, measurement range = 80 μm, JIS2001, GAUSS filter, cutoff value λc = 2.5 mm, The measurement was performed with the cut-off value λs = 8.0 μm, and the step was calculated from the cross-sectional curve. Further, polishing was performed after just polishing for a time corresponding to 15% of the polishing time until just polishing, a model test at the time of excessive polishing was performed, and a film thickness and a step were measured again.

  Tables 1 and 2 show the pH measurement results for the chemical mechanical polishing slurries of Examples and Comparative Examples, and the measurement results of the step difference between the insulating film and the stopper film during just polishing and excessive polishing.

  When the results of Table 1 and Table 2 were compared, when polishing was performed using each of the chemical mechanical polishing slurries of the examples of the present invention, it did not have a ring structure instead of the water-soluble clathrate compound. Compared to the cases where each slurry of Comparative Examples 1 and 2 containing dextran or sucrose is used, both the level difference during just polishing (just level difference) and the level difference during excessive polishing are reduced, and the amount of increase in level difference due to excessive polishing is also increased. It was less. Compared with the cases where the slurries of Comparative Examples 3 to 5 containing a polymer compound instead of the water-soluble clathrate compound were used, the amount of increase in level difference due to excessive polishing was reduced. Further, when the slurry of Comparative Example 6 having a low water-soluble clathrate-containing concentration was used, a sufficient effect was not obtained.

  As described above in detail, the present invention is a chemical mechanical polishing slurry capable of extremely reducing the step between the insulating film and the stopper film in the polishing process of the insulating film and interlayer insulating film in shallow trench isolation. Is to provide. In addition, the present invention provides a polishing method and a manufacturing method for a substrate, which can obtain a film to be polished having a very small step and can improve the yield at the time of manufacturing the substrate.

Claims (7)

α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and one or more water-soluble inclusion compounds selected from the group consisting of these derivatives (a), cerium oxide (b) and water ( c) a slurry for chemical mechanical polishing, wherein the water-soluble clathrate compound (a) has a weight average molecular weight of 200 to 1,000,000, and is 0.000 based on the total amount of the slurry. A chemical mechanical polishing slurry for a shallow trench isolation process, contained in the range of 6 % by mass to 5 % by mass. The slurry for chemical mechanical polishing according to claim 1, wherein the average particle size of cerium oxide (b) is 0.5 nm to 1,000 nm . The slurry for chemical mechanical polishing according to claim 1, wherein the cerium oxide (b) is contained in an amount of 0.1 to 30% by mass relative to the total amount of the slurry. The slurry for chemical mechanical polishing according to any one of claims 1 to 3 , wherein the pH is 3 to 12.5. While supplying the chemical mechanical polishing slurry according to any one of claims 1 to 4 between the substrate and the polishing pad, the substrate and the polishing pad are moved relatively to polish the insulating film on the substrate. , Polishing method of substrate. While supplying the chemical mechanical polishing slurry according to any one of claims 1 to 4 between the substrate and the polishing pad, the substrate and the polishing pad are moved relatively to polish the insulating film on the substrate. The manufacturing method of a board | substrate including the process to do. The method according to claim 5 or 6 , wherein the insulating film on the substrate is a silicon oxide film and / or a silicon nitride film.