JP2009144080A - Polishing liquid composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing liquid composition reducing waviness and polishing at an economical polishing speed. <P>SOLUTION: The polishing liquid composition contains a polishing material and water, wherein the polishing material contains first polishing particles having a shape factor SF-1 that represents a roundness degree of particles, of from 140 to 250, and second polishing particles having a shape factor SF-1 of from 100 to 130. The first polishing particles are alumina particles having an average particle diameter of from 0.01 to 0.45 μm; and the second polishing particles have an average particle diameter larger than the average particle diameter of the first polishing particles. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polishing liquid composition and a method for producing a substrate.

With the rapid spread of computers and the start of digital broadcasting, etc., high capacity and small diameter hard disk drives are required. For example, as a method for increasing the recording density of a memory hard disk used in a hard disk drive, it has been proposed to reduce the flying height of the magnetic head and reduce the unit recording area. However, in order to cope with the low flying height of the head, it is necessary to reduce the surface roughness, waviness, roll-off, etc. of the surface of the hard disk substrate. In order to satisfy such requirements, an abrasive slurry (Patent Documents 1 to 4) that can reduce scratches on the substrate after polishing and a polishing liquid composition (Patent Document 5) that can reduce roll-off are known. Also, in the semiconductor field, high integration and high speed are advancing, and in particular, miniaturization of wiring is required for high integration (Patent Document 6).
JP 2000-15560 A JP 2000-458 A JP 2001-155332 A JP-A-5-177554 JP 2002-167575 A JP 2003-249469 A

  In order to achieve the surface quality necessary for increasing the density of the memory hard disk substrate, it is important to reduce the waviness from the viewpoint of reducing the flying height of the magnetic head. In the manufacturing process of a semiconductor device, since the depth of focus when exposing a photoresist is becoming shallower, further surface smoothness including reduction of waviness is desired.

  The present invention provides a polishing composition that can reduce waviness on the surface of the substrate and a method for producing a substrate that can produce a substrate with improved surface quality such as waviness.

  The polishing composition of the present invention is a polishing composition containing an abrasive and water, and the first abrasive particles having a shape factor SF-1 of 140 to 250 indicating the degree of roundness of the abrasive. And second abrasive particles having a shape factor SF-1 of 100 to 130, the first abrasive particles are alumina particles having an average particle size of 0.01 to 0.45 μm, and the average particle size of the second abrasive particles Is a polishing composition which is larger than the average particle size of the first abrasive particles. As will be described later, the shape factor SF-1 is multiplied by 100 by dividing the area of a circle whose diameter is the maximum diameter of abrasive particles obtained by electron microscope observation by the projected area of the abrasive particles obtained by electron microscope observation. Value. Moreover, the manufacturing method of the board | substrate of this invention (henceforth the manufacturing method of this invention) is a manufacturing method of a board | substrate which has the process of grind | polishing a to-be-polished board | substrate using the said polishing liquid composition.

  According to the present invention, the effect that the undulation of the substrate is reduced and a hard disk substrate suitable for high recording density and a highly integrated semiconductor device can be manufactured is preferably achieved. In addition, according to the present invention, the effect that the substrate can be polished without impairing productivity at an economical polishing rate is preferably achieved.

  In the present invention, the “undulation” of the substrate refers to irregularities on the surface of the substrate having a wavelength longer than the roughness, and in this specification, includes an undulation of a wavelength of 0.5 to 5 mm unless otherwise specified. By reducing the waviness of the substrate, the flying height of the magnetic head can be reduced, and the recording density of the magnetic disk substrate can be improved. The present invention relates to polishing using a combination of abrasive particles having a small particle size and high abrasive power (hereinafter also referred to as first abrasive particles) and abrasive particles having a large particle size and low abrasive power (hereinafter also referred to as second abrasive particles). The liquid composition is based on the knowledge that the waviness of the substrate after polishing can be reduced. In the present invention, a shape factor SF-1 (described later) indicating the degree of roundness of the particles is used. The mechanism by which the undulation reduction effect of the present invention is achieved is still unclear, but the abrasive particles having a large average particle size and low polishing power increase the distance between the substrate and the polishing pad, and the average particle size is small and the polishing power is low. It is estimated that the waviness on the substrate surface is reduced because the high abrasive particles polish the convex portions on the substrate surface. However, these assumptions do not limit the present invention.

  As described above, the polishing liquid composition of the present invention is a polishing liquid composition containing an abrasive and water, and the shape factor SF-1 indicating the degree of roundness of the abrasive is 140 to 250. A first abrasive particle and a second abrasive particle having a shape factor SF-1 of 100 to 130, the first abrasive particle is an alumina particle having an average particle diameter of 0.01 to 0.45 μm, and the second abrasive particle One of the technical features is that the average particle size of the particles is larger than the average particle size of the first abrasive particles. By providing such technical features, the present invention can polish the substrate without impairing the productivity at an economical polishing rate and reduce the waviness of the substrate after polishing, and is suitable for high recording density. The effect that a hard disk substrate or a highly integrated semiconductor device can be manufactured is preferably exhibited.

[Abrasive]
The abrasive in the polishing composition of the present invention includes first abrasive particles and second abrasive particles described later, and may also include abrasive particles other than the first abrasive particles and the second abrasive particles as necessary. The abrasive particles used as the first abrasive particles are alumina particles such as α-alumina and alumina sol, and α-alumina particles are more preferable from the viewpoints of improving the polishing rate, preventing surface defects, and reducing waviness. Specific examples of the abrasive particles used as the second abrasive particles include particles such as alumina, silicon carbide, diamond, magnesium oxide, zinc oxide, cerium oxide, zirconium oxide, colloidal silica, and fumed silica. For rough polishing when the Ni-P plated aluminum alloy substrate is the substrate to be polished, the second polishing particles are preferably alumina particles such as α-alumina and alumina sol, and the α-alumina particles improve the polishing rate. It is more preferable from the viewpoint of preventing surface defects and reducing waviness. As the abrasive particles other than the first abrasive particles and the second abrasive particles, intermediate alumina is preferable, and θ-alumina is preferable as the intermediate alumina.

  The 1st abrasive particle in this invention says the abrasive particle whose shape factor SF-1 which shows the degree of roundness is 140-250. The first abrasive particles having SF-1 in the above range can contribute to the improvement of the polishing rate. From the viewpoint of improving the polishing rate, the SF-1 of the first abrasive particles is preferably in the range of 150 to 250, more preferably in the range of 150 to 200, and further in the range of 150 to 175. Preferably, it is still more preferable that it is the range of 150-160. The 2nd abrasive particle in this invention says the abrasive particle whose SF-1 is 100-130. The second abrasive particles having SF-1 in the above range can contribute to swell reduction. From the viewpoint of reducing waviness, the SF-1 of the second abrasive particles is preferably in the range of 100 to 125, more preferably in the range of 100 to 120, and still more preferably in the range of 100 to 115. More preferably, it is in the range of 100 to 110.

  In the present invention, the shape factor SF-1 indicates the degree of roundness, and the abrasive particles obtained by observing the area of a circle whose diameter is the maximum diameter of the abrasive particles obtained by observing with an electron microscope. The value is obtained by dividing the projected area by 100 and multiplying by 100 (see Japanese Patent No. 3253228). SF-1 indicates that the closer to 100, the closer to a spherical shape. Although it does not restrict | limit especially as said electron microscope, For example, a transmission electron microscope (TEM) and a scanning electric microscope (SEM) can be used. SF-1 can be measured as described in the examples, but the measurement method is not limited to this.

  The average particle size of the first abrasive particles is 0.01 to 0.45 μm, more preferably 0.05 to 0.45 μm, and further preferably 0.1 to 0.45 μm, from the viewpoint of improving the polishing rate and reducing waviness. preferable. The average particle size of the second abrasive particles is larger than the average particle size of the first abrasive particles from the viewpoint of reducing waviness. The average particle diameter of the second abrasive particles is preferably 0.4 to 1 μm, more preferably 0.4 to 0.8 μm, still more preferably 0.4 to 0.7 μm, from the viewpoint of reducing waviness. Even more preferred is ~ 0.6 μm. The average particle size of these abrasive particles is observed with a scanning electron microscope (preferably 3000 to 30000 times) or a transmission electron microscope (preferably 10,000 to 300000 times), and image analysis is performed. It can be determined as the particle size. Specifically, it can be determined as in the embodiments described later.

  The ratio between the average particle size of the second abrasive particles and the average particle size of the first abrasive particles (average particle size of the second abrasive particles / average particle size of the first abrasive particles) is from the viewpoint of improving the polishing rate and reducing waviness. Preferably, it is 1.1-5, More preferably, it is 1.2-3, More preferably, it is 1.3-2.

  The content of the abrasive in the polishing composition is preferably 0.05% by weight or more, more preferably 0.1% by weight or more, and more preferably 0.5% by weight or more from the viewpoint of improving the polishing rate and reducing waviness. More preferably, 1% by weight or more is even more preferable. Moreover, from a viewpoint of roll-off reduction and surface quality improvement, 40 weight% or less is preferable, 35 weight% or less is more preferable, 30 weight% or less is further more preferable, and 25 weight% or less is still more preferable. Therefore, the content of the abrasive in the polishing composition is preferably 0.05 to 40% by weight, more preferably 0.1 to 35% by weight, still more preferably 0.5 to 30% by weight, and 1 to 25%. Even more preferred is weight percent. The weight ratio of the first abrasive particles to the second abrasive particles (weight of the first abrasive particles / weight of the second abrasive particles) is in the range of 0.1 to 4 from the viewpoint of improving the polishing rate and reducing waviness. Preferably 0.2 to 3, more preferably 0.3 to 2, and still more preferably 0.4 to 1.5.

  The content of coarse particles having a particle diameter of 1 μm or more in the abrasive is 0.2% by weight or less, preferably 0.15% by weight or less, more preferably 0, from the viewpoint of reducing the sticking of the abrasive particles to the substrate. .1% by weight or less, more preferably 0.05% by weight or less. In addition, the content of coarse particles having a particle diameter of 3 μm or more in the abrasive is preferably 0.05% by weight or less, more preferably 0.04% by weight or less, and still more preferably 0.03% by weight from the same viewpoint. Hereinafter, it is still more preferably 0.02% by weight or less, and still more preferably 0.01% by weight or less. The “coarse particles having a particle diameter of 1 μm or more” or “coarse particles having a particle diameter of 3 μm or more” includes not only primary particles but also secondary particles.

  For the measurement of the content of coarse particles in the abrasive, a number counting method (Sizing Particle Optical Sensing method) can be used. Specifically, the content can be determined by measuring the particle size of the abrasive particles with “Accumizer 780” manufactured by Particle Sizing Systems, USA. The method for controlling the content of coarse particles in the abrasive is not particularly limited, and a general dispersion method or particle removal method performed during or after the production of the polishing composition can be employed. Specifically, the abrasive particle slurry uniformly crushed by a wet circulation type bead mill is removed by coarse particles by sedimentation by a stationary precipitation method, a centrifugal separator or the like, or by microfiltration with a filter medium, etc. You can control the amount. The coarse particle removal treatment may be carried out alone or in two or more methods, and the treatment conditions, the number of treatments, and the treatment order of a combination of two or more methods can be appropriately selected and set.

[water]
The water in the polishing composition of the present invention is used as a medium, and distilled water, ion exchange water, ultrapure water, or the like can be used. The content of water in the polishing composition is preferably 55% by weight or more, more preferably 75% by weight or more, and even more preferably 85% by weight or more, from the viewpoint of handleability (viscosity) of the polishing composition. 90% by weight or more is even more preferable. Further, from the viewpoint of improving the polishing rate and reducing piercing and waviness, it is preferably 99.8% by weight or less, more preferably 99.3% by weight or less, and further preferably 98.8% by weight or less. Accordingly, the content of water in the polishing composition is preferably 55 to 99.8% by weight, more preferably 75 to 99.8% by weight, still more preferably 85 to 99.3% by weight, and 90 to 98.8. Even more preferred is weight percent.

[Acid and / or its salt]
The polishing composition of the present invention preferably contains an acid and / or a salt thereof from the viewpoints of improving the polishing rate and reducing waviness. The acid that can be used in the present invention has a pK1 of preferably 7 or less, more preferably 5 or less, still more preferably 3 or less, and even more preferably 2 or less, from the viewpoint of improving the polishing rate and reducing piercing and waviness. It is an acid. Here, pK1 is a logarithmic value of the reciprocal of the first acid dissociation constant (25 ° C.). PK1 of each compound is described, for example, in Chemical Handbook 4th edition (basic edition) II, p316 to 325 (edited by the Chemical Society of Japan).

  Specific examples of acids that can be used in the present invention are shown below. Examples of inorganic acids include monovalent mineral acids such as nitric acid, hydrochloric acid, perchloric acid, and amidosulfuric acid, and polyvalent mineral acids such as sulfuric acid, sulfurous acid, phosphoric acid, pyrophosphoric acid, polyphosphoric acid, phosphonic acid, and phosphinic acid. . Organic acids include formic acid, acetic acid, glycolic acid, lactic acid, propanoic acid, hydroxypropanoic acid, butyric acid, benzoic acid, glycine and other monocarboxylic acids, oxalic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid Acid, itaconic acid, malic acid, tartaric acid, citric acid, isocitric acid, phthalic acid, polyvalent carboxylic acids such as nitrotriacetic acid, ethylenediaminetetraacetic acid, alkylsulfonic acids such as methanesulfonic acid and paratoluenesulfonic acid, ethylphosphoric acid, butylphosphorus Examples thereof include alkylphosphoric acids such as acids, organic phosphonic acids such as phosphonohydroxyacetic acid, hydroxylidene diphosphonic acid, phosphonobutanetricarboxylic acid, and ethylenediaminetetramethylenephosphonic acid. Among these, from the viewpoint of improving the polishing rate and reducing piercing and undulation, polyvalent acids are preferred, more preferred are polyvalent mineral acids, polyvalent carboxylic acids, and organic phosphonic acids, and even more preferred are polyvalent mineral acids and polyvalent acids. Divalent carboxylic acid. Here, the polyvalent acid refers to an acid having hydrogen capable of generating two or more hydrogen ions in the molecule. Further, nitric acid, sulfuric acid, alkylsulfonic acid and polyvalent carboxylic acid are preferable from the viewpoint of preventing surface contamination of the object to be polished.

  Although the said acid may be used independently, it is preferable to mix and use 2 or more types. In particular, when polishing a metal surface such as a Ni-P plated substrate, the metal ions of the object to be polished are eluted during polishing, the pH of the polishing composition increases, and a high polishing rate cannot be obtained. In order to reduce the pH change, it is preferable to use a combination of an acid having a pK1 of less than 2.5 and an acid having a pK1 of 2.5 or more, and an acid having a pK1 of 1.5 or less and a pK1 of 2.5 or more. It is more preferable to use in combination with an acid. When these two or more acids are contained, considering the improvement in polishing rate, reduction of waviness, and availability, the acids having a pK1 of less than 2.5 are minerals such as nitric acid, sulfuric acid, phosphoric acid, and polyphosphoric acid. It is preferable to use an acid or an organic phosphonic acid. On the other hand, as the acid having a pK1 of 2.5 or more, from the same viewpoint, organic carboxylic acids such as acetic acid, succinic acid, malic acid, tartaric acid, citric acid, itaconic acid, maleic acid and the like are preferable. Among them, succinic acid, apple Acid, tartaric acid, citric acid, itaconic acid and maleic acid are preferred, and citric acid is more preferred. Further, from the viewpoint of improving the polishing rate and reducing waviness, when using an organic carboxylic acid having a pK1 of 2.5 or more, it is more preferable to use a combination of an oxycarboxylic acid and a divalent or higher polyvalent carboxylic acid. . For example, examples of the oxycarboxylic acid include citric acid, malic acid, and tartaric acid, and examples of the polyvalent carboxylic acid include succinic acid, maleic acid, and itaconic acid. Accordingly, it is preferable to use one or more of these in combination, and among them, it is preferable to combine citric acid and polyvalent carboxylic acid.

  The content of the acid and / or salt thereof in the polishing composition is preferably 0.002% by weight or more, more preferably 0.005% by weight or more, and still more preferably, from the viewpoint of improving the polishing rate and reducing waviness. 0.007% by weight or more, and still more preferably 0.01% by weight or more. The content is preferably 20% by weight or less, more preferably 15% by weight or less, still more preferably 10% by weight or less, and still more preferably 5% by weight or less, from the viewpoint of surface quality and economy. That is, the content of the acid and / or salt thereof in the polishing composition is preferably 0.002 to 20% by weight, more preferably 0.005 to 15% by weight, and still more preferably 0.007 to 10% by weight. Even more preferably, it is 0.01 to 5% by weight. From the viewpoint of improving the polishing rate, the weight ratio of the acid having a pK1 of less than 2.5 to the acid having a pK1 of 2.5 or more [(an acid having a pK1 of less than 2.5) / (an acid having a pK1 of 2.5 or more). )] Is preferably 9/1 to 1/9, more preferably 7/1 to 1/7, and still more preferably 5/1 to 1/5.

[Oxidant]
The polishing composition in the present invention preferably contains an oxidizing agent from the viewpoints of improving the polishing rate and reducing piercing and waviness. Examples of the oxidizing agent used in the present invention include peroxides, metal peroxo acids or salts thereof, or oxygen (oxo) acids or salts thereof. Oxidizing agents are roughly classified into inorganic oxidizing agents and organic oxidizing agents according to their structures. Examples of inorganic oxidants include hydrogen peroxide; alkali metal or alkaline earth metal peroxides such as sodium peroxide, potassium peroxide, calcium peroxide, barium peroxide, and magnesium peroxide; sodium peroxocarbonate, peroxo Peroxocarbonates such as potassium carbonate; peroxosulfuric acid such as ammonium peroxodisulfate, sodium peroxodisulfate, potassium peroxodisulfate, peroxomonosulfuric acid or the like; peroxo such as sodium peroxophosphate, potassium peroxophosphate, ammonium peroxophosphate Peroxoborate such as sodium peroxoborate and potassium peroxoborate; peroxochromate such as sodium peroxochromate and potassium peroxochromate; sodium permanganate Permanganates such as sodium and potassium permanganate; halogen-containing substances such as sodium perchlorate, potassium perchlorate, sodium hypochlorite, sodium periodate, potassium periodate, sodium iodate, potassium iodate Oxyacid salts; and inorganic acid metal salts such as iron (III) chloride, iron (III) sulfate, and aluminum nitrate. Examples of organic oxidizing agents include percarboxylic acids such as peracetic acid, performic acid, and perbenzoic acid; peroxides such as t-butyl peroxide and cumene peroxide; and organic acids such as iron (III) citrate Examples thereof include iron (III) salts. Among these, an inorganic oxidizing agent is preferable from the viewpoints of improvement in polishing rate, availability, and handleability such as solubility in water. Of these, hydrogen peroxide, sodium peroxoborate, sodium iodate and potassium iodate are preferred. These oxidizing agents may be used alone or in combination of two or more.

  The content of the oxidizing agent in the polishing composition is preferably 0.002% by weight or more, more preferably 0.005% by weight or more, from the viewpoint of improving the polishing rate and reducing waviness and substrate contamination. 007% by weight or more is more preferable, and 0.01% by weight or more is even more preferable. Moreover, from a viewpoint of roll-off reduction and surface quality, 20 weight% or less is preferable, 15 weight% or more is more preferable, 10 weight% or less is more preferable, and 5 weight% or less is further more preferable. That is, the content of the oxidizing agent in the polishing composition is preferably 0.002 to 20% by weight, more preferably 0.005 to 15% by weight, still more preferably 0.007 to 10% by weight, Even more preferred is ˜5 wt%.

[PH of polishing composition]
It is preferable that the pH of the polishing composition of the present invention is appropriately determined according to the type of the object to be polished and the required quality. For example, the pH of the polishing composition is preferably less than 7 from the viewpoint of improving the polishing rate and reducing waviness, and from the viewpoint of corrosion prevention of the processing machine and the safety of the worker, more preferably 0.1 to 6, More preferably, it is 0.5-5, Still more preferably, it is 1-5, More preferably, it is 1-4, More preferably, it is 1-3. Where necessary, the pH may be selected from inorganic acids such as nitric acid and sulfuric acid, organic acids such as oxycarboxylic acids, polyvalent carboxylic acids, aminopolycarboxylic acids and amino acids, and metal salts and ammonium salts thereof, ammonia, sodium hydroxide, It can adjust by mix | blending basic substances, such as potassium hydroxide and an amine, with a desired quantity suitably.

[Surfactant]
The surfactant improves the wettability of the polishing composition to the polishing pad, and is effective in reducing the waviness of the substrate surface and the edge of the outer periphery of the substrate (hereinafter sometimes referred to as “roll-off”). A compound. Examples of the surfactant include nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants. From the viewpoint of reducing waviness, nonionic surfactants, cationic surfactants and anionic surfactants are preferred, nonionic surfactants and cationic surfactants are more preferred, and nonionic surfactants are preferred. Further preferred. When a nonionic surfactant is used as the surfactant, for example, the lipophilicity is adjusted by the number of alkyl chains of the lipophilic group or the average number of added moles of the oxyethylene group and oxypropylene group of the hydrophilic group. For other surfactants, it is preferable to adjust by increasing the number of alkyl chains of the lipophilic group.

The nonionic surfactant is not particularly limited, but those represented by the following general formula (I) can be preferably used.
Y- (EO) _l (PO) _m -Z (I)
[In the formula (I), EO is an oxyethylene group, PO is an oxypropylene group, l and m represent the average number of added moles, l + m is 8 to 100, and Y is an —OR ¹ group. , —OH group, or —OCOR ² group (R ¹ and R ² are hydrocarbon groups), Z is —R ³ group, hydrogen atom, or —COR ⁴ group (R ³ and R ⁴ are hydrocarbon groups) It is. ]

  Examples of nonionic surfactants other than the above include copolymers having a structural unit represented by the following formula (II) and a structural unit derived from a hydrophobic monomer having a solubility in 100 g of water at 20 ° C. of 2 g or less. Can be mentioned. In the copolymer, the addition of the structural unit represented by the following formula (II) and the structural unit derived from the hydrophobic monomer may be random, block or graft, and a combination thereof. May be.

In the above formula (II), R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group having 1 to 4 carbon atoms, AO is an oxyalkylene group having 1 to 8 carbon atoms, and p is 0 or 1, n is the total average added mole number of AO and is a number of 6 to 300, and the proportion of the oxyethylene group in (AO) _n is 80 mol% or more.

  The hydrophobic monomer has a solubility in 100 g of water at 20 ° C. of 2 g or less, that is, hardly soluble in water. The structural unit derived from the hydrophobic monomer is preferably at least one structural unit selected from the group consisting of structural units represented by the following formulas (III) to (V) from the viewpoint of reducing roll-off. The structural unit represented by the following formula (III) is more preferable. Moreover, from the viewpoint of the stability of the copolymer, the structural unit derived from the hydrophobic monomer is preferably a structural unit represented by the following formula (V).

In the above formula (III), R ³ is a hydrogen atom or a methyl group, X is an oxygen atom or an NH group, R ⁴ is an alkyl group having 4 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms. In the formula (IV), R ⁵ is a hydrogen atom or a methyl group, R ⁶ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, AO is an oxyalkylene group having 2 to 4 carbon atoms, m is the total average added mole number of AO and is a number of 3 to 150, and the proportion of oxypropylene group and oxybutylene group in (AO) _m is 80 mol% or more, and in the above formula (V), R ⁷ is a hydrogen atom or a methyl group, and R ⁸ is a hydrogen atom or an alkyl group having 1 to 30 carbon atoms.

  The copolymer may contain other monomers in addition to the monomer for forming the structural unit represented by the formula (II) and the hydrophobic monomer.

  From the viewpoint of improving the polishing rate, the content of the surfactant in the polishing composition of the present invention is preferably 5% by weight or less, more preferably 3% by weight or less, and further preferably 1% by weight or less. Further, from the viewpoint of improving the wettability of the polishing liquid composition, 0.001% by weight or more is preferable, 0.01% by weight or more is more preferable, and 0.05% by weight or more is more preferable. That is, the content of the surfactant in the polishing composition is preferably 0.001 to 5% by weight, more preferably 0.01 to 3% by weight, and still more preferably 0.05 to 1% by weight.

[Other ingredients]
The polishing liquid composition of the present invention may further contain other components depending on the purpose of improving the polishing rate and reducing waviness and other purposes. Examples of other components include metal oxide abrasive grains such as colloidal silica, fumed silica, and colloidal titanium oxide, inorganic salts, thickeners, rust preventives, and basic substances. Examples of inorganic salts include ammonium nitrate, ammonium sulfate, potassium sulfate, nickel sulfate, aluminum nitrate, aluminum sulfate, and ammonium sulfamate. The inorganic salt can be used for the purpose of improving the polishing rate, improving the roll-off, and preventing caking of the polishing composition. The other components may be used alone or in combination of two or more. The content of the other component in the polishing composition is preferably 0.05 to 20% by weight, more preferably 0.05 to 10% by weight, and still more preferably 0.05 to 5% from the viewpoint of economy. % By weight. If necessary, a bactericidal agent, an antibacterial agent and the like can be blended in the polishing composition of the present invention as further other components. The content of these bactericides and antibacterial agents in the polishing liquid composition is preferably 0.0001 to 0.1% by weight from the viewpoint of exerting the function, and from the viewpoint of influence on polishing performance and economy. More preferably, it is 0.001-0.05 weight%, More preferably, it is 0.002-0.02 weight%.

[Method for preparing polishing liquid composition]
The method for preparing the polishing composition in the present invention is not limited at all, and can be prepared by mixing at least the abrasive, water, and, if necessary, a surfactant. From the standpoint of ease of preparation, the polishing composition of the present invention is preferably prepared by mixing the first abrasive particles and the second abrasive particles. The dispersion of the abrasive particles is not particularly limited, and can be performed using a homomixer, a homogenizer, an ultrasonic disperser, a stirrer such as a wet ball mill, or the like. The concentration of each component in the polishing liquid composition is a preferable concentration when polishing, but when the polishing liquid composition is produced as a concentrated liquid, the concentration described above is used before or during use. It is preferable to dilute so that The polishing composition can be produced by adding and mixing the target components by any method.

[Substrate manufacturing method]
The production method of the present invention includes a step of polishing a substrate to be polished using the polishing liquid composition of the present invention (hereinafter sometimes referred to as “polishing step using the polishing liquid composition of the present invention”). A method for manufacturing a substrate. By including the polishing step using the polishing composition of the present invention, the substrate manufacturing method of the present invention enables economical polishing rate polishing and manufacture of a substrate with reduced waviness. . In addition, it is characterized by including the process of grind | polishing a to-be-polished board | substrate using the polishing liquid composition of this invention, Other conditions, processes, etc. are not restrict | limited at all. Examples of the substrate manufacturing method of the present invention include a hard disk substrate manufacturing method and a semiconductor device manufacturing method described later.

  In the “polishing step using the polishing composition of the present invention”, the polishing composition of the present invention is supplied to the polishing surface of the substrate to be polished, the polishing pad is brought into contact with the polishing surface, and a predetermined pressure (polishing load) is applied. ) While moving the polishing pad or the substrate to be polished. In addition, the said grinding | polishing can be performed with a conventionally well-known grinding | polishing apparatus. The polishing composition may be used as it is, or diluted if it is a concentrated solution. In the case of diluting the concentrated liquid, the dilution ratio is not particularly limited, and can be appropriately determined according to the concentration of each component in the concentrated liquid (abrasive content, etc.), polishing conditions, and the like.

  Examples of the substrate to be polished include magnetic disk substrates such as magnetic disks, magneto-optical disks, and optical disks, photomask substrates, optical lenses, optical mirrors, optical prisms, and substrates for precision components such as semiconductor devices. The material of the substrate to be polished suitable for the polishing composition of the present invention is, for example, a metal or a semimetal such as silicon, aluminum, nickel, tungsten, copper, tantalum, titanium, or an alloy thereof, glass, glassy carbon, Examples thereof include glassy substances such as amorphous carbon, ceramic materials such as alumina, silicon dioxide, silicon nitride, tantalum nitride, and titanium carbide, and resins such as polyimide resin. Among these, it is suitable for an object to be polished containing a metal such as aluminum, nickel, tungsten, or copper and an alloy containing these metals as a main component. For example, a Ni—P plated aluminum alloy substrate or a glass substrate such as crystallized glass or tempered glass is more suitable, and a Ni—P plated aluminum alloy substrate is more suitable. There is no particular limitation on the shape of the object to be polished. For example, the polishing liquid composition of the present invention has a shape having a flat portion such as a disk shape, a plate shape, a slab shape, a prism shape, or a shape having a curved surface portion such as a lens. Things are used. Among them, it is excellent for polishing a disk-shaped workpiece.

  The polishing pad used in the present invention is not particularly limited, and for example, a polishing pad made of a nonwoven or porous organic polymer can be used. There is no particular limitation on the shape and size of the polishing pad. The material of the polishing pad is not particularly limited, and examples thereof include organic polymers such as urethane, and organic polymers containing various additives such as carbon and ceria. Examples of the urethane compound that is one of the constituent components of the polishing pad include two types of polyether-based urethanes and polyester-based urethanes, depending on the type of the compound that reacts with the raw material isocyanate. In general, polyether urethane has a strong lipophilic property, and polyester urethane tends to have a strong hydrophilic property. In general, the use of polyester-based urethane pads tends to reduce the waviness of the substrate after polishing, and the use of polyether-based urethane pads increases the polishing rate and increases the pad life (usable time). It tends to be long. Therefore, in actual production, it is preferable to use a polyether urethane polishing pad from the viewpoint of reducing waviness. In addition, in a polishing pad in which polyether-based urethane and polyester-based urethane are mixed, it is preferable that the content of polyether-based urethane is large from the viewpoint of achieving both improvement in polishing rate and reduction in waviness.

  The polishing load means the pressure of the surface plate applied to the polishing surface of the substrate to be polished during polishing. The polishing load in the production method of the present invention is preferably 50 kPa or less, more preferably 40 kPa or less, and even more preferably 30 kPa or less, from the viewpoint of reducing the sticking of abrasive particles to the substrate and reducing the waviness of the substrate after polishing. The polishing load is preferably 3 kPa or more, more preferably 5 kPa or more, and even more preferably 7 kPa or more, from the viewpoint of productivity (polishing rate). Therefore, the polishing load is preferably 3 to 50 kPa, more preferably 5 to 40 kPa, and even more preferably 7 to 30 kPa. The polishing load can be adjusted by applying air pressure or weight to the surface plate or the substrate. Other polishing conditions (type of polishing machine, polishing temperature, polishing rate, supply amount of polishing liquid composition, etc.) are not particularly limited.

The supply rate of the polishing liquid composition of the present invention is preferably 0.25 mL / min or less, more preferably 0.2 mL / min or less per 1 cm ^{2 of the} substrate to be polished, from the viewpoint of low cost. The supply rate is preferably 0.01 mL / min or more per 1 cm ^{2 of the} substrate to be polished, more preferably 0.025 mL / min or more, and even more preferably 0.05 mL / min or more because the polishing rate can be further improved. is there. Accordingly, the supply rate is preferably 0.01 to 0.25 mL / min per 1 cm ^{2 of the} substrate to be polished, more preferably 0.025 to 0.2 mL / min, and still more preferably 0.05 to 0.15 mL. / Min.

  According to the manufacturing method of the present invention, the substrate to be polished can be polished at an economical polishing rate, and the waviness of the substrate after polishing can be reduced. The swell can be measured as in the examples described later.

[Method of manufacturing hard disk substrate]
As described above, since a hard disk substrate can be produced by polishing using the polishing composition of the present invention, the present invention relates to a method for producing a hard disk substrate as one aspect thereof. The polishing composition of the present invention is more effective in the polishing process, but can be similarly applied to other polishing processes such as a lapping process. In this case, examples of the substrate to be polished include a substrate obtained by subjecting an aluminum alloy, glass, glassy carbon, or the like to Ni-P plating, and plating or vapor deposition of various metal compounds instead of the Ni-P plating. It may be a substrate or the like coated with.

  In the method for producing a hard disk of the present invention, a multi-stage polishing method having two or more stages of polishing processes is preferable. In the process prior to the final polishing process which is the final process, “the polishing composition of the present invention is used. It is preferable to perform the “polishing step”. In the polishing composition used in the final polishing step, from the viewpoint of the surface quality of the hard disk substrate, for example, from the viewpoint of reducing waviness, reducing the surface roughness, and reducing surface defects such as scratches, the abrasive particles (abrasive grains) The average particle size of the primary particles is preferably 0.1 μm or less, more preferably 0.08 μm or less, further preferably 0.05 μm or less, and even more preferably 0.03 μm or less. . Further, from the viewpoint of improving the polishing rate, the average particle diameter is preferably 0.005 μm or more, and more preferably 0.01 μm or more.

  Examples of the abrasive particles in the polishing composition used in the final polishing step include fumed silica, colloidal silica, and the like, and colloidal silica is preferable from the viewpoint of reducing surface roughness and reducing surface defects such as scratches. . As an average particle diameter of the primary particle of colloidal silica, 0.005-0.08 micrometer is preferable, 0.005-0.05 micrometer is more preferable, 0.01-0.03 micrometer is further more preferable. In the final polishing step, when using abrasive particles having an average primary particle diameter of 0.005 to 0.1 μm, the surface roughness is reduced, the abrasive particles are stuck, and productivity (polishing time) is reduced. From the viewpoint, the polishing amount is preferably 0.05 to 0.5 μm, more preferably 0.1 to 0.4 μm, and further preferably 0.2 to 0.4 μm.

  There are no particular restrictions on other conditions (type of polishing machine, polishing temperature, polishing rate, supply amount of polishing liquid, etc.) when performing final polishing, and the polishing liquid composition of the present invention was used as the polishing load. It may be the same as the polishing load exemplified in the polishing step. The polishing amount can be determined as in the examples described later. The hard disk substrate obtained by the method for manufacturing a hard disk substrate of the present invention is suitable for increasing the recording density, for example, because the waviness of the substrate is remarkably reduced and the surface quality is improved.

[Semiconductor substrate polishing method, semiconductor device manufacturing method]
The polishing composition of the present invention can reduce waviness when used for polishing a semiconductor substrate. Therefore, the present invention, as one aspect thereof, relates to a method for polishing a semiconductor substrate. Examples of the semiconductor substrate include silicon wafers, and other materials such as elemental semiconductors such as Si or Ge, compound semiconductors such as GaAs, InP, or CdS, mixed crystal semiconductors such as InGaAs, HgCdTe, and the like. A substrate is mentioned.

  Further, the “polishing process using the polishing composition of the present invention” is a polishing process performed in the manufacturing process of a semiconductor device, for example, a polishing process of a silicon wafer (bare wafer), a formation process of a buried element isolation film, an interlayer insulation When applied to a film flattening step, a buried metal wiring forming step, a buried capacitor forming step, a chemical mechanical polishing (CMP) step, etc., waviness after polishing can be reduced. Therefore, this invention relates to the manufacturing method of the semiconductor device containing "the grinding | polishing process using the polishing liquid composition of this invention" as another aspect.

  The manufacturing method of the semiconductor device includes a thin film forming step in which one main surface on a semiconductor substrate forms a crocodile thin film, and a concavo-convex surface forming step in which the semiconductor substrate of the thin film forms a concavo-convex pattern on the opposite side of the flank A polishing step of polishing the concavo-convex surface using the polishing liquid composition of the present invention can be included. You may perform a thin film formation process in multiple times as needed. As a thin film formed in a thin film formation process, conductor layers, such as an insulating layer, a metal layer, a semiconductor layer, etc. are mentioned, for example. Examples of the material included in the insulating layer include silicon oxide, silicon nitride, and polysilicon. Examples of the method for forming the uneven surface include a conventionally known lithography method. In the lithography method, photoresist application, exposure, development, etching, photoresist removal, and the like are performed in this order. The semiconductor device obtained by the semiconductor device manufacturing method of the invention can be highly integrated, for example, because the surface waviness after polishing during manufacturing is significantly reduced and the surface quality is improved.

1. Preparation of polishing liquid composition Abrasive particles shown in Table 1 below, 0.5% by weight of sulfuric acid (98% by weight product), 0.6% by weight of citric acid, 0.5% by weight of ammonium sulfate, hydrogen peroxide (35% by weight) % Product, manufactured by Asahi Denka Co., Ltd.) 0.6% by weight and ion-exchanged water (remainder) were mixed and stirred. The obtained slurry was filtered with a back filter (manufactured by Hayward Japan, model number: PE1-P03H-403) to obtain polishing liquid compositions of Examples 1 to 10 and Comparative Examples 1 to 6 shown in Table 1 below. . In Examples 3 to 7, as a surfactant, a copolymer of SMA / PEGMA (EO: 23), SMA / PEGMA, and stearyl methacrylate and methoxypolyethylene glycol methacrylate (EO average addition mole number: 23 mol). The weight ratio is 20/80), a copolymer of lauryl methacrylate and methoxypolyethylene glycol methacrylate (EO average addition mole number is 120 moles) (LMA / PEGMA (EO: 120)), and the weight ratio of LMA to PEGMA is 10/90. ), A copolymer of styrene and methoxypolyethylene glycol methacrylate (EO average addition mole number is 23 mol) (St / PEGMA (EO: 23), St: PEGMA weight ratio is 20/80), behenyl methacrylate and methoxypolyethylene. Glycol methacrylate A copolymer (BMA / PEGMA (EO: 90), the weight ratio of BMA and PEGMA is 30/70), and stearyl alcohol with 140 mol of polyoxyethylene groups (C18 -O- (EO) 140-H) was added respectively. The shape factor (SF-1) of the abrasive particles shown in Table 1 below was determined according to the following method.
Method for Measuring Shape Factor SF-1 of Abrasive Particles A sample is observed with a transmission electron microscope “JEM-2000FX” (80 kV, 1 to 50,000 times) manufactured by JEOL according to the instructions attached by the manufacturer of the microscope, and TEM A (Transmission Electron Microscope) image was photographed. This photograph is taken into a personal computer as image data by a scanner, and the maximum diameter and projection area of each particle are measured using analysis software “WinROOF ver. 3.6” (distributor: Mitani Corporation). The area of the circle is divided by the projected area and multiplied by 100 to calculate SF-1.
Method for Measuring Average Particle Size of Abrasive Particles A TEM image of a sample is photographed by the same method as described above, and the photograph is taken into a personal computer as image data by a scanner. Analysis software “WinROOF ver. 3.6” (distributor) : Mitani Shoji Co., Ltd.), the equivalent circle diameter of each abrasive particle is obtained, and it is used as the diameter. After analyzing the data of 1000 or more abrasive particles, the spreadsheet software "EXCEL" The average particle diameter based on the number of abrasive particles was obtained from Microsoft.

2. Polishing method The surface of a substrate made of a Ni-P plated aluminum alloy having a thickness of 1.27 mm and a diameter of 3.5 inches is polished by a double-sided processing machine under the following setting conditions, and Ni used as a substrate for a magnetic recording medium A polished product of an aluminum alloy substrate plated with -P was obtained. In addition, the amplitude of the wave | undulation (wavelength: 0.5-5 mm) in the measurement using "Zygo NewView5032" was 1.6 nm for the said board | substrate used for grinding | polishing.
Setting conditions for the double-sided machine Double-sided machine: Speed Fam Co., Ltd., 9B type double-sided machine Polishing load: 7.8 kPa
Plate rotation speed: 45r / min
Polishing liquid composition supply flow rate: 100 mL / min
Polishing time: 4 min
Number of substrates loaded: 10 Polishing pad: Ester-based polyurethane pad, average pore size 43 μm

3. Evaluation methods
Evaluation of Waviness Two were selected arbitrarily from the ten substrates after polishing, and both sides of each selected substrate were measured at 180 ° every 2 points (total 8 points) under the following conditions. The average value of the eight measured values was calculated as the swell of the substrate. The results are shown in Table 1 below.
Equipment: Zygo NewView 5032
Lens: 2.5x Michelson
Zoom ratio: 0.5
Remove: Cylinder
Filter: FFT Fixed Band Pass
Measurement wavelength: 0.5-5mm
Area: 4.33mm x 5.77mm
Measuring method of polishing rate The weight of each substrate before and after polishing is measured using a weigh scale ("BP-210S" manufactured by Sartorius) to determine the weight change of each substrate, and the average value of 10 substrates is used as the weight reduction amount. The value obtained by dividing the result by the polishing time was defined as the weight reduction rate. This weight reduction rate was introduced into the following formula and converted into a polishing rate (μm / min). The results are shown in Table 1 below.
Polishing rate (μm / min) = weight reduction rate (g / min) / substrate single-sided area (mm ² ) / Ni-P plating density (g / cm ³ ) × 10 ⁶
(Calculated as substrate one side area: 6597 mm ² , Ni-P plating density: 7.9 g / cm ³ )

  As shown in the above table, it can be seen that when the polishing liquid compositions of Examples 1 to 10 are used, the surface waviness of the substrate to be polished is reduced as compared with the polishing liquid compositions of Comparative Examples 1 to 6. Moreover, when the polishing liquid composition of Examples 1-7 is used, it turns out that the wave | undulation of the substrate surface can be reduced, without reducing a polishing rate. Further, when the polishing composition of Examples 3 to 7 to which a surfactant is further added is used, the swell is further reduced as compared with the polishing composition of Example 2 that does not use a surfactant. I understand that.

  By using the present invention, for example, a hard disk substrate suitable for higher recording density and a highly integrated semiconductor device can be provided.

Claims (7)

A polishing liquid composition containing an abrasive and water,
The abrasive contains first abrasive particles whose shape factor SF-1 indicating the degree of roundness of the particles is 140 to 250, and second abrasive particles whose shape factor SF-1 is 100 to 130, One polishing particle is an alumina particle having an average particle diameter of 0.01 to 0.45 μm, and the average particle diameter of the second abrasive particle is larger than the average particle diameter of the first abrasive particle. The polishing composition according to claim 1, wherein the second abrasive particles are alumina particles having an average particle diameter of 0.4 to 1 μm. The polishing composition according to claim 1 or 2, wherein a weight ratio of the first abrasive particles to the second abrasive particles (weight of the first abrasive particles / weight of the second abrasive particles) is 0.1 to 4. The polishing composition according to any one of claims 1 to 3, further comprising an oxidizing agent. The polishing liquid composition according to any one of claims 1 to 4, further comprising an acid and / or a salt thereof. A method for manufacturing a substrate, comprising a step of polishing a substrate to be polished using the polishing composition according to any one of claims 1 to 5. The method for manufacturing a substrate according to claim 6, wherein the substrate is a hard disk substrate.