JP2016127268A - Composition for silicon wafer polishing liquid or composition kit for silicon wafer polishing liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for a silicon wafer polishing liquid and a composition kit for a silicon wafer polishing liquid, capable of stably reducing surface roughness (haze) and surface defect (LPD) on a polished silicon wafer surface.SOLUTION: A composition for a silicon wafer polishing liquid of the present invention is obtained by mixing a silica particle dispersion containing a silica particle, a basic compound and an aqueous medium and an additive solution containing a water-soluble polymer compound and an aqueous medium. The silica particle dispersion is obtained by keeping a mixed liquid with a pH at 25°C of 9 or more and 11 or less for one day or more at 10°C or above and 80°C or below, the mixed liquid being obtained by mixing the silica particle, the basic compound and the aqueous medium, or the silica particle dispersion has a transmittance of light with a wavelength of 600 nm of 5.0% or more and 30% or less in one of cases where the content of the silica particle thereof is 5 mass% or more and 20 mass% or less.SELECTED DRAWING: None

Description

  The present invention relates to a polishing composition for a silicon wafer, a method for producing the same, a method for polishing a silicon wafer to be polished and a method for producing a semiconductor substrate using the polishing composition for a silicon wafer. The present invention also relates to a polishing composition kit for a silicon wafer, a method for producing the same, a method for polishing a silicon wafer to be polished and a method for manufacturing a semiconductor substrate using the polishing composition composition for a silicon wafer. The present invention also relates to a silica particle dispersion.

  In recent years, design rules for semiconductor devices have been increasingly miniaturized due to increasing demand for higher recording capacity of semiconductor memories. For this reason, the depth of focus is reduced in photolithography performed in the manufacturing process of semiconductor devices, and there is a demand for reduction of surface defects (LPD: Light point defects) and surface roughness (Haze) of silicon wafers (bare wafers). It is getting stricter.

  In order to improve the quality of silicon wafers, polishing of silicon wafers is performed in multiple stages. In particular, finish polishing performed at the final stage of polishing is performed for the purpose of reducing surface roughness and reducing surface defects such as particles, scratches, and pits.

  As a polishing liquid composition used for polishing silicon wafers, it aims to improve storage stability, guarantee a polishing rate that ensures good productivity, and reduce surface defects (LPD) and surface roughness (haze). In addition, a polishing composition for a silicon wafer containing silica particles, a nitrogen-containing basic compound, and a water-soluble polymer compound containing a structural unit derived from an acrylamide derivative such as hydroxyethylacrylamide (HEAA) is disclosed ( Patent Document 1). Further, for the purpose of improving the haze level, a polishing liquid composition containing silica particles, hydroxyethyl cellulose (HEC), polyethylene oxide, and an alkali compound is disclosed (Patent Document 2). In addition, for the purpose of reducing particles adhering to the wafer surface without lowering the haze level, silica particles, basic compounds such as ammonia, water-soluble polymer compounds such as HEC, and 1 to 10 alcoholic hydroxyl groups A polishing liquid composition containing a compound having the same is disclosed (Patent Document 3).

  These polishing liquid compositions are stored and transported in a concentrated state as long as their storage stability is not impaired, from the viewpoint of economy such as reduction in production and transportation costs, and used for polishing silicon wafers. In many cases, it is diluted with ion-exchanged water or the like as required by the user. In addition, the polishing composition is prepared by separately storing an abrasive dispersion containing abrasive grains, a basic compound, and water, and an aqueous solution of an aqueous polymer, and these are mixed during use and diluted with water as necessary. In some cases, it is a two-component type (Patent Document 4).

JP 2013-222863 A JP 2004-128089 A Japanese Patent Laid-Open No. 11-116942 WO2014 / 148399

  However, when the concentrated polishing composition is diluted and then used for polishing silicon wafers, or after mixing the liquids constituting the two-component polishing composition, the resulting polishing composition is used as silicon. When used for wafer polishing, sometimes the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface are insufficiently reduced.

  In the present invention, a polishing composition for a silicon wafer capable of stably reducing the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface, a method for producing the same, and the polishing composition for the silicon wafer A method for polishing a silicon wafer to be polished and a method for manufacturing a semiconductor substrate using the object are provided. Moreover, in this invention, the polishing composition composition for silicon wafers which can reduce stably the surface roughness (haze) and surface defect (LPD) of the surface of the polished silicon wafer, its manufacturing method, and the said silicon wafer use A polishing method for a silicon wafer to be polished and a method for manufacturing a semiconductor substrate using a polishing composition kit are provided. Moreover, in this invention, the silica particle dispersion liquid used for preparation of the polishing liquid composition for silicon wafers which can reduce stably the surface roughness (haze) and surface defect (LPD) of the surface of the polished silicon wafer is provided. To do.

  One aspect of the polishing composition for a silicon wafer according to the present invention is a mixture of a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. A polishing composition for a silicon wafer obtained as described above, wherein the silica particle dispersion has a pH of 9 to 11 at 25 ° C. obtained by mixing the silica particles, the basic compound, and the aqueous medium. The liquid mixture was maintained at 10 ° C. or higher and 80 ° C. or lower for 1 day or longer.

  Another aspect of the polishing composition for a silicon wafer according to the present invention includes a silica particle dispersion containing silica particles, a basic compound, and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. A polishing composition for a silicon wafer obtained by mixing, wherein the silica particle dispersion has a light transmittance of a wavelength of 600 nm, and the content of the silica particles is 5 mass% or more and 20 mass% or less. In the case, it is 5.0% or more and 30% or less.

  Another aspect of the polishing composition for a silicon wafer according to the present invention includes a silica particle dispersion containing silica particles, a basic compound, and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. A polishing composition for a silicon wafer obtained by mixing, wherein the silica particle dispersion has a light transmittance at a wavelength of 600 nm of 5.0% to 30%, and the silica particle dispersion at 25 ° C. The pH is 9 or more and 11 or less, and the content of the silica particles is 10 mass% or more and 15 mass% or less.

  Another aspect of the polishing composition for a silicon wafer according to the present invention includes a silica particle dispersion containing silica particles, a basic compound, and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. A silicon wafer polishing liquid composition obtained by mixing, obtained by freeze-drying the silica particle dispersion and the BET specific surface area of the freeze-dried silica particles obtained by air-drying the silica particle dispersion The BET specific surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) obtained by dividing by the BET specific surface area of the air-dried silica particles is 1.3 or more and 10 or less.

  One aspect of the polishing composition composition for a silicon wafer according to the present invention includes a silica particle dispersion (first liquid) containing silica particles, a basic compound, and an aqueous medium, a water-soluble polymer compound, and an aqueous medium. An aqueous solution of additive (second liquid), and the silica particle dispersion (first liquid) has a pH at 25 ° C. of 9 or more obtained by mixing the silica particles, the basic compound, and the aqueous medium. The liquid mixture of 11 or less was obtained by holding at 10 ° C. or higher and 80 ° C. or lower for 1 day or longer.

  Another aspect of the polishing composition composition for a silicon wafer according to the present invention includes a silica particle dispersion (first liquid) containing silica particles, a basic compound, and an aqueous medium, a water-soluble polymer compound, and an aqueous medium. An additive aqueous solution (second liquid), and the silica particle dispersion (first liquid) has a light transmittance of 600 nm, and the silica particle content is 5 mass% or more and 20 mass% or less. In such a case, it is 5.0% or more and 30% or less.

  Another aspect of the polishing composition composition for a silicon wafer according to the present invention includes a silica particle dispersion (first liquid) containing silica particles, a basic compound, and an aqueous medium, a water-soluble polymer compound, and an aqueous medium. An additive aqueous solution (second liquid) containing, wherein the silica particle dispersion (first liquid) has a light transmittance of a wavelength of 600 nm, and the silica particle dispersion has a pH of 9 to 11 at 25 ° C. In the case where the content of silica particles is 10% by mass or more and 15% by mass or less, the content is 5.0% or more and 30% or less.

  Another aspect of the polishing composition composition for a silicon wafer according to the present invention includes a silica particle dispersion (first liquid) containing silica particles, a basic compound, and an aqueous medium, a water-soluble polymer compound, and an aqueous medium. An additive aqueous solution (second liquid) containing, the BET specific surface area of the freeze-dried silica particles obtained by freeze-drying the silica particle dispersion, and the air-dried silica obtained by air-drying the silica particle dispersion The BET specific surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) obtained by dividing by the BET specific surface area of the particles is 1.3 or more and 10 or less.

  One aspect of the method for producing a polishing composition for a silicon wafer of the present invention comprises a step of mixing a water-soluble polymer compound and an aqueous medium to obtain an aqueous additive solution, silica particles, a basic compound, and an aqueous medium. A step of obtaining a silica particle dispersion by holding a mixed solution having a pH of 9 or more and 11 or less at 25 ° C. obtained by mixing at 10 ° C. or more and 80 ° C. or less for 1 day, and the silica particle dispersion and the additive Mixing with an aqueous solution.

  One aspect of a method for producing a polishing composition kit for a silicon wafer according to the present invention includes a step of mixing a water-soluble polymer compound and an aqueous medium to obtain an aqueous additive solution, silica particles, a basic compound, and an aqueous medium. And a step of obtaining a silica particle dispersion by holding a mixed solution having a pH of 9 or more and 11 or less at 25 ° C. obtained by mixing at 10 ° C. or more and 80 ° C. or less for 1 day or more.

  One aspect of the silica particle dispersion of the present invention is a silica particle dispersion containing silica particles, a basic compound, and an aqueous medium, wherein the silica particle dispersion has a light transmittance of a wavelength of 600 nm. In a case where the pH at 25 ° C. of the dispersion is 9 to 11 and the content of the silica particles is 10% to 15% by mass, it is 5.0% to 30%.

  Another aspect of the silica particle dispersion of the present invention is a silica particle dispersion containing silica particles, a basic compound, and an aqueous medium, wherein the lyophilized silica particles obtained by freeze-drying the silica particle dispersion The BET specific surface area is obtained by dividing the BET specific surface area by the BET specific surface area of the air-dried silica particles obtained by air-drying the silica particle dispersion (BET specific surface area of freeze-dried silica particles / air-dried silica particles BET specific surface area) is 1.3 or more and 10 or less.

  Another aspect of the silica particle dispersion of the present invention is a silica particle dispersion containing silica particles, a basic compound, and an aqueous medium, wherein the lyophilized silica particles obtained by freeze-drying the silica particle dispersion The BET specific surface area is obtained by dividing the BET specific surface area by the BET specific surface area of the air-dried silica particles obtained by air-drying the silica particle dispersion (BET specific surface area of freeze-dried silica particles / air-dried silica particles BET specific surface area) is 1.3 or more and 10 or less.

  One aspect of the method for producing a polishing composition for a silicon wafer of the present invention is an aqueous additive solution containing a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and a water-soluble polymer compound and an aqueous medium. And a step of mixing.

  The manufacturing method of the semiconductor substrate of this invention includes the process of grind | polishing a to-be-polished silicon wafer using the polishing liquid composition for silicon wafers of this invention.

  The polishing method for a silicon wafer to be polished according to the present invention includes a step of polishing the silicon wafer to be polished using a polishing composition for a silicon wafer.

  The manufacturing method of the semiconductor substrate of this invention includes the process of grind | polishing a to-be-polished silicon wafer using the polishing liquid composition kit for silicon wafers of this invention.

  The polishing method of a silicon wafer to be polished according to the present invention includes a step of polishing the silicon wafer to be polished using a polishing composition composition kit for silicon wafer.

  According to the present invention, a polishing composition for a silicon wafer, a method for producing the same, and the silicon wafer capable of stably reducing the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface It is possible to provide a method for polishing a silicon wafer to be polished and a method for manufacturing a semiconductor substrate, using the polishing liquid composition.

  Further, according to the present invention, a polishing composition kit for a silicon wafer, a method for producing the same, which can stably reduce the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface, and A polishing method for a silicon wafer to be polished and a method for manufacturing a semiconductor substrate using the silicon wafer polishing composition kit can be provided.

  In addition, according to the present invention, silica particle dispersion used for the preparation of a polishing composition for a silicon wafer that can stably reduce the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface. A liquid can be provided.

  A silicon wafer polishing liquid composition containing silica particles, a basic compound, and a water-soluble polymer compound (hereinafter sometimes simply referred to as “polishing liquid composition”) is used to polish a silicon wafer to be polished. Among these, the water-soluble polymer compound can be adsorbed on both the silica particles and the silicon wafer to be polished. Therefore, the water-soluble polymer compound brings the silica particles closer to the silicon wafer to be polished, suppresses the silica particles that cause deterioration of the surface roughness (haze) from directly contacting the silicon wafer to be polished, and It acts to suppress corrosion of the wafer surface due to the basic compound that causes deterioration of the surface roughness (haze). Therefore, the water-soluble polymer compound contributes to improving the polishing rate, improving the detachability of particles (silica particles and polishing waste) in the polishing process of the polished silicon wafer, and reducing the surface roughness (haze). Yes. Further, the improvement of the particle detachability contributes to the reduction of surface defects (LPD).

  However, even when a polishing composition having the same composition is used, surface roughness (haze) and surface defects (LPD) may vary. As a result of searching for the cause of this variation, the present inventor found that the cause is that excessive adsorption of the water-soluble polymer compound to the silica particles is caused by the above action of the water-soluble polymer compound on the wafer, specifically, It was thought that this was hindering the inhibition of the corrosion of the wafer surface and the improvement of particle detachment by the conductive polymer compound. Then, a silica particle dispersion obtained by aging a mixture obtained by mixing silica particles, a basic compound and an aqueous medium at a predetermined temperature for a predetermined time is used for the preparation of a polishing liquid composition, specifically Is obtained by mixing silica particles, a basic compound, and an aqueous medium, and maintaining a mixture liquid having a pH of 9 to 11 at 25 ° C. at 10 ° C. to 80 ° C. for 1 day or longer. After sufficiently stabilizing the sum layer, by mixing the silica particles and the water-soluble polymer compound, excessive adsorption of the water-soluble polymer compound to the silica particles is suppressed. It has been found that the above-described action on the wafer is sufficiently exhibited. However, these are estimations, and the present invention is not limited to these mechanisms.

  After the hydration layer on the surface of the silica particles has been sufficiently stabilized, the polishing composition obtained by mixing the silica particle dispersion and the additive aqueous solution is immediately used for polishing a silicon wafer to be polished. In addition, surface roughness (haze) and surface defects (LPD) can be stably reduced.

  Further, after the silica particle dispersion is prepared, when the silica particle dispersion is stored (ripened) for a predetermined time under predetermined conditions, the light transmittance is lower than that immediately after the silica particle dispersion is prepared. From this, the present inventor has found that there is a correlation between the transmittance of the silica particle dispersion and the stability of the hydrated layer of silica particles. Specifically, when the content of the silica particles in the silica particle dispersion is any of 5% by mass to 20% by mass, the light transmittance of the silica particle dispersion at a wavelength of 600 nm is 5.0%. The silica particle dispersion liquid when the pH at 25 ° C. of the silica particle dispersion liquid is 9 or more and 11 or less and the silica particle content is 10 mass% or more and 15 mass% or less. When the transmittance of light having a wavelength of 600 nm is 5.0% or more and 30% or less, it is assumed that the hydrated layer of silica particles is sufficiently stabilized, and the silica particle dispersion having such optical characteristics is dispersed. If the polishing liquid composition prepared using the liquid is used, the above-described action of the water-soluble polymer compound on the wafer is sufficiently exerted, and the surface roughness (haze) and surface defects (LPD) of the silicon wafer surface are reduced. Stable Can become possible (there hereinafter referred to as "the stabilizing effect of the present invention" also.) Found.

  Further, when the aging period of the silica particle dispersion is increased, a tendency is observed that the surface roughness (haze) and surface defects (LPD), particularly surface defects (LPD), of the silicon wafer surface are reduced. Further, when the aging period becomes longer, a tendency is observed that the BET specific surface area of freeze-dried silica particles (hereinafter also referred to as “freeze-dried silica particles”) obtained by freeze-drying the silica particle dispersion is increased. . However, there is no correlation between the BET specific surface area of the air-dried silica particles obtained by air-drying the silica particle dispersion (hereinafter also referred to as “air-dried silica particles”) and the aging time. . From these, during the aging period, the Si-O bond on the surface of the silica particles in the silica particle dispersion liquid undergoes alkaline hydrolysis, whereby reversible pores are formed on the surface of the silica particles, and freeze-dried. It is presumed that the BET specific surface area of the silica particles is increased. Then, the BET specific surface area ratio (BET specific surface area of the freeze-dried silica particles) obtained by storing for a predetermined time under a predetermined condition and obtained by dividing the BET specific surface area of the freeze-dried silica particles by the BET specific surface area of the air-dried silica particles. When a polishing composition prepared using a silica particle dispersion having a BET specific surface area / air-dried silica particles of 1.3 or more and 10 or less is used, the presence of the pores causes the water-soluble polymer compound silica. Because excessive adsorption to the particles is suppressed, or the contact area of the silica particles to the silicon wafer is reduced, and in the polishing process of the polished silicon wafer, the removability of the silica particles adsorbed to the silicon wafer is improved. It is presumed that the surface roughness (haze) and surface defects (LPD) can be stably reduced.

  In one aspect, the present invention is a one-component polishing comprising a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. It is a liquid composition. The one-component type polishing composition of the present invention is a silica particle dispersion prepared by mixing silica particles, a basic compound, and an aqueous medium and having a pH of 9 to 11 at 25 ° C. The transmittance of light having a wavelength of 600 nm is 5.0% or more when the silica particle content is any one of 5% by mass or more and 20% by mass or less obtained by holding at 80 ° C. or less for 1 day or more. The wavelength of the silica particle dispersion when it is 30% or less, the pH at 25 ° C. of the silica particle dispersion is 9 or more and 11 or less, and the content of the silica particles is 10 mass% or more and 15 mass% or less. The light transmittance at 600 nm is 5.0% to 30%, or the value obtained by dividing the BET specific surface area of the freeze-dried silica particles by the BET specific surface area of the air-dried silica particles is 1.3 to 10 Using things Since it is manufactured, the polishing performance is unstable when the polishing liquid composition is used for polishing immediately after the preparation of the polishing liquid composition, which was a problem of the conventional one-pack type polishing liquid composition, The surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface can be reduced even when the polishing composition is immediately after preparation.

  In another aspect, the present invention provides a silica particle dispersion (first liquid) containing silica particles, a basic compound, and an aqueous medium, an aqueous additive solution (first solution) containing a water-soluble polymer compound and an aqueous medium. Is a polishing liquid composition kit for silicon wafers (two-pack type polishing liquid composition) in which they are stored in a state where they are not mixed with each other. The silica particle dispersion (first liquid) has a light transmittance at a wavelength of 600 nm of 5.0% or more and 30% or less when the content of silica particles is 5% by mass or more and 20% by mass or less. When the pH of the silica particle dispersion is 9 to 11 and the content of silica particles is 10% to 15% by weight, the silica particle dispersion has a wavelength of 600 nm. The light transmittance is 5.0% or more and 30% or less, or the value obtained by dividing the BET specific surface area of freeze-dried silica particles by the BET specific surface area of air-dried silica particles is 1.3 or more and 10 or less. is there. The silica particle dispersion is, for example, a mixture having a pH of 9 or more and 11 or less at 25 ° C. obtained by mixing silica particles, a basic compound, and an aqueous medium, and holding at 10 ° C. or more and 80 ° C. or less for 1 day or more. Can be obtained.

  In the present invention, “in the case where the light transmittance at a wavelength of 600 nm of the silica particle dispersion is any of the content of the silica particles of 5% by mass to 20% by mass, 5.0% to 30%. % "Or less". This is because the silica particle dispersion used in the preparation of the one-component polishing composition of the present invention and the polishing composition kit for silicon wafers of the present invention (hereinafter referred to as the following). The content of the silica particles in the silica particle dispersion (first liquid) constituting the “polishing liquid composition preparation kit” may be 5% by mass or more and 20% by mass or less. Not specified, for example, the content ratio of the silica particles and the basic compound in the silica particle dispersion at any concentration of 5% by mass to 20% by mass of the silica particles, and the content Silica particles with the same quantitative ratio A dispersion is also included in the silica particle dispersion. That is, when the content of the silica particles is not within the above range, the transmittance is obtained by adjusting the content of the silica particles to 5% by mass or more and 20% by mass or less by changing the amount of the aqueous medium. Can do.

  In the present invention, “the light transmittance of the silica particle dispersion at a wavelength of 600 nm is such that the silica particle dispersion has a pH of 9 to 11 at 25 ° C., and the content of the silica particles is 10% by mass to 15%. In any case of mass% or less, it is defined as 5.0% or more and 30% or less. ”This is the silica particle dispersion used in the preparation of the one-part polishing composition of the present invention. And the content of silica particles in the silica particle dispersion (first liquid) constituting the liquid and the polishing composition preparation kit of the present invention is specified to be 10% by mass or more and 15% by mass or less. Instead, for example, the transmittance of light having a wavelength of 600 nm is 5.0% or more and 30% or less, the pH at 25 ° C. is 9 or more and 11 or less, preferably the pH is 10 ± 0.3, and the content of silica particles is 10% to 15% by mass, good Preferably, the silica particle dispersion also includes a silica particle dispersion in which the content ratio of the silica particles and the basic compound in the 10% by mass silica particle dispersion is equal. That is, the transmittance of the silica particle dispersion can be easily determined by clarifying the pH of the silica particle dispersion and the content of the silica particles.

  However, the transmittance of light at a wavelength of 600 nm of the silica particle dispersion is 5.0% to 30%, the pH of the silica particle dispersion is 9 to 11 at 25 ° C., and the content of the silica particles is 10 When the content is from 15% by mass to 15% by mass, it is an embodiment of the preferred polishing liquid composition of the present invention.

  The polishing composition preparation kit of the present invention has a pH at 25 ° C. obtained by mixing silica particles, a basic compound, and an aqueous medium as a silica particle dispersion (first liquid). Wavelength of 600 nm when the mixed liquid of 9 or more and 11 or less is obtained by holding at 10 ° C. or more and 80 ° C. or less for 1 day or more, and the content of silica particles is 5% by mass or more and 20% by mass or less The transmittance of the light is 5.0% or more and 30% or less, or the silica particle dispersion has a pH of 9 or more and 11 or less at 25 ° C., and the silica particle content is 10% by mass or more and 15% by mass or less. In the case where the transmittance of light at a wavelength of 600 nm of the silica particle dispersion is 5.0% to 30%, or the BET specific surface area of the freeze-dried silica particles is divided by the BET specific surface area of the air-dried silica particles. did When the polishing liquid composition obtained by mixing the two liquids, which was a problem of the conventional two-pack type polishing liquid composition, is used for polishing immediately. Even if the polishing composition obtained by mixing two liquids constituting the polishing composition preparation kit of the present invention is immediately used for polishing, the polishing performance is unstable. Further, the surface roughness (haze) and surface defects (LPD) of the silicon wafer can be reduced.

  In the polishing composition preparation kit of the present invention, the silica particle dispersion (first liquid) and the aqueous additive solution (second liquid) are stored separately from each other. The mixing of the aqueous solution of the additive (second liquid) with the aqueous solution of the additive (second liquid) and the aqueous solution of the additive (second liquid) adjusts the amount of the aqueous solution of the additive (second liquid). The concentration of the water-soluble polymer compound and the like in the polishing liquid composition obtained by mixing the liquid) can be adjusted, and various polishing liquid compositions can be prepared.

  Hereinafter, the silica particle dispersion and the aqueous additive solution that are used for preparing the polishing composition of the present invention or that constitute the polishing composition preparation kit of the present invention will be described in detail.

<Silica particle dispersion>
[Silica particles (component A)]
The silica particle dispersion contains silica particles (component A) as an abrasive. Specific examples of the silica particles include colloidal silica and fumed silica. Colloidal silica is more preferable from the viewpoint of improving the surface smoothness of the silicon wafer.

  The usage form of the silica particles (component A) is preferably a slurry from the viewpoint of operability. When the silica particles are colloidal silica, the colloidal silica is preferably obtained from a hydrolyzate of alkoxysilane from the viewpoint of preventing contamination of the silicon wafer by alkali metal, alkaline earth metal, or the like. Silica particles obtained from the hydrolyzate of alkoxysilane can be produced by a conventionally known method. The preferred pH range for the silica particles is 7 ± 0.5 neutral.

  The average primary particle diameter of the silica particles (component A) is not particularly limited from the viewpoint of the stabilization effect of the present invention, but is preferably 5 nm or more, more preferably 10 nm or more, and still more preferably 15 nm, from the viewpoint of securing the polishing rate. As mentioned above, it is still more preferably 20 nm or more. In addition, from the viewpoint of ensuring the polishing rate and reducing surface defects (LPD), the thickness is preferably 50 nm or less, more preferably 45 nm or less, and even more preferably 40 nm or less.

  In particular, when colloidal silica is used as the silica particles (component A), the average primary particle diameter is preferably 5 nm or more, more preferably, from the viewpoint of securing the polishing rate and reducing the surface defects (LPD) of the silicon wafer. Is 10 nm or more, more preferably 15 nm or more, still more preferably 20 nm or more, and preferably 50 nm or less, more preferably 45 nm or less, still more preferably 40 nm or less.

The average primary particle diameter of the silica particles is calculated using a specific surface area S (m ² / g) calculated by a BET (nitrogen adsorption) method. A specific surface area can be measured by the method as described in an Example, for example.

  The degree of association of the silica particles is preferably 3.0 or less, more preferably 2.5 or less, still more preferably 2.3 or less, preferably from the viewpoint of ensuring the polishing rate and reducing the surface defects of the silicon wafer. 1.1 or more, more preferably 1.5 or more, and even more preferably 1.8 or more. The shape of the silica particles is preferably a so-called spherical type and a so-called mayu type. When the silica particles are colloidal silica, the degree of association is preferably 3.0 or less, more preferably 2.5 or less, and even more preferably 2.3 or less, from the viewpoint of securing the polishing rate and reducing surface defects. Yes, preferably 1.1 or more, more preferably 1.5 or more, and still more preferably 1.8 or more.

The association degree of silica particles is a coefficient representing the shape of silica particles, and is calculated by the following formula. The average secondary particle diameter is a value measured by a dynamic light scattering method, and can be measured using, for example, the apparatus described in the examples.
Degree of association = average secondary particle size / average primary particle size

  The method for adjusting the degree of association of the silica particles is not particularly limited. For example, JP-A-6-254383, JP-A-11-214338, JP-A-11-60232, JP-A-2005-060217, A method described in JP-A-2005-060219 or the like can be employed.

  From the viewpoint of reducing surface defects (LPD) of the silicon wafer, Na contained in the silica particles (component A) used for the preparation of the silica particle dispersion is preferably 100 ppb mass% or less, more preferably 50 ppb mass% or less. Preferably it is 30 ppb mass% or less. The concentration of impurities such as Na contained in the silica particles (component A) can be measured by methods such as plasma height analysis (ICP) and atomic absorption analysis.

  The content of the silica particles (component A) contained in the silica particle dispersion is preferably 3% by mass or more, more preferably 5% by mass or more, and still more preferably from the viewpoint of economy such that production and transportation costs can be reduced. Is 8% by mass or more. Further, the content of silica particles in the silica particle dispersion is preferably 25% by mass or less, more preferably 20% by mass or less, and further preferably 15% by mass or less from the viewpoint of improving storage stability.

The BET specific surface area of the freeze-dried silica particles is preferably 95 m ² / g or more, more preferably from the viewpoint of stably reducing the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface. Is 110 m ² / g or more, more preferably 150 m ² / g or more. From the viewpoint of improving the polishing rate, it is preferably 400 m ² / g or less, more preferably 300 m ² / g or less, still more preferably 250 m ² / g or less. It is. In addition, the BET specific surface area of a freeze-dried silica particle can be measured by the method as described in the below-mentioned Example.

  The BET specific surface area ratio, which is the value obtained by dividing the BET specific surface area of freeze-dried silica particles by the BET specific surface area of air-dried silica particles, stabilizes the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface. From the viewpoint of enabling reduction, it is 1.3 or more, preferably 1.5 or more, more preferably 2.0 or more, 10 or less, preferably 5.0 or less, more preferably 3.0 or less. . The BET specific surface area of the air-dried silica particles is the BET specific surface area of the air-dried silica particles obtained by air-drying the silica particle dispersion by air flow, and can be measured by the method described in the examples below.

  The amount of silanol groups per unit mass of the freeze-dried silica particles is preferably 2.1 mmol / from the viewpoint of stably reducing the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface. g or more, more preferably 2.3 mmol / g or more, still more preferably 2.4 mmol / g or more, preferably 10 mmol / g or less, more preferably 5.0 mmol / g or less, still more preferably 3.0 mmol / g. It is as follows. In addition, the amount of silanol groups per unit mass of freeze-dried silica particles can be measured by the method described in the examples described later.

  The porosity of the freeze-dried silica particles is preferably 1.5% or more, more preferably from the viewpoint of stably reducing the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface. Is 4.0% or more, more preferably 6.0% or more, preferably 30% or less, more preferably 20% or less, still more preferably 15% or less. In addition, the porosity of freeze-dried silica particles can be measured by the method described in the examples below.

[Basic compound (component B)]
The silica particle dispersion contains a water-soluble basic compound (component B) from the viewpoint of improving storage stability, ensuring a polishing rate, and reducing surface defects (LPD) and surface roughness of the silicon wafer.

  The water-soluble basic compound (component B) is at least one nitrogen-containing basic compound selected from amine compounds and ammonium compounds. The solubility of the nitrogen-containing basic compound (component B) contained in the silica particle dispersion is not particularly limited as long as it is dissolved in the working concentration range of the present invention. Here, “water-soluble” means water ( 20 g) having a solubility of 0.5 g / 100 ml or more, preferably having a solubility of 2 g / 100 ml or more. “Water-soluble basic compound” means that when dissolved in water Refers to a compound that exhibits basicity.

  Examples of at least one nitrogen-containing basic compound selected from amine compounds and ammonium compounds include ammonia, ammonium hydroxide, ammonium carbonate, ammonium hydrogen carbonate, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, Monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N-methyl-N, N-diethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, N, N-dibutylethanol Amine, N- (β-aminoethyl) ethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, ethylenediamine, hexamethylenedia Down, piperazine hexahydrate, anhydrous piperazine, 1- (2-aminoethyl) piperazine, N- methylpiperazine, diethylenetriamine, and tetramethylammonium and the like hydroxide. These nitrogen-containing basic compounds may be used as a mixture of two or more. As the nitrogen-containing basic compound contained in the silica particle dispersion, the surface roughness (haze) and surface defects (LPD) of the silicon wafer are reduced, the storage stability of the silica particle dispersion is improved, and the polishing rate is ensured. From this viewpoint, ammonia is more preferable.

  The content of the basic compound (component B) contained in the silica particle dispersion is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, further from the viewpoint of improving the dispersibility of the silica particles. Preferably it is 0.5 mass% or more. The content of the basic compound in the silica particle dispersion is preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less, from the viewpoint of improving storage stability.

  The mass ratio of the silica particles (component A) and the basic compound (component B) contained in the silica particle dispersion (silica particles / basic compound) is preferably 0.6 or more from the viewpoint of improving storage stability. More preferably, it is 1 or more, More preferably, it is 3 or more. Moreover, from a viewpoint of the dispersibility improvement of a silica particle, Preferably it is 500 or less, More preferably, it is 200 or less, More preferably, it is 100 or less.

[Aqueous medium]
Examples of the aqueous medium contained in the silica particle dispersion include water such as ion-exchanged water and ultrapure water, or a mixed medium of water and a solvent. As the solvent, a solvent that can be mixed with water (for example, Alcohols such as ethanol) are preferred. Among these, ion-exchanged water or ultrapure water is more preferable, and ultrapure water is more preferable from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. In the case where the aqueous medium is a mixed medium of water and a solvent, the ratio of water to the entire mixed medium is not particularly limited as long as the effect of the present invention is not hindered. 95 mass% or more is preferable, 98 mass% or more is more preferable, and 100 mass% is still more preferable substantially.

  The light transmittance at a wavelength of 600 nm of the silica particle dispersion is such that when the content of silica particles in the silica particle dispersion is 5% by mass or more and 20% by mass or less, surface defects (LPD) and surface of the silicon wafer From the viewpoint of reducing roughness (haze), it is preferably 5.0% or more, more preferably 5% or more, still more preferably 8.0% or more, still more preferably 8% or more, and even more preferably 11% or more. Preferably, it is 30% or less, more preferably 24% or less, and still more preferably 16% or less.

  From the viewpoint of avoiding uncertainties, the measurement conditions of the silica particle dispersion to be measured for the transmittance of light having a wavelength of 600 nm are 10 masses, and the silica particle dispersion has a 25 ° C. The pH at is from 9 to 11. The pH is preferably 10 ± 0.3.

<Additive aqueous solution>
[Water-soluble polymer compound (component C)]
The solubility of the water-soluble polymer compound (component C) contained in the aqueous additive solution constituting the polishing liquid composition of the present invention is not particularly limited as long as it dissolves in the polishing concentration range of the present invention. The “water-soluble” of the water-soluble polymer compound means that it has a solubility of 0.5 g / 100 ml or more, preferably 2 g / 100 ml or more, in water (20 ° C.). The polyoxyalkylene compound (component D) described later is a water-soluble polymer compound, but is excluded from the category of component C.

  As a monomer which is a supply source constituting the water-soluble polymer compound (component C), from the viewpoint of ensuring a polishing rate, reducing surface defects (LPD) and surface roughness (haze) of a silicon wafer, for example, Examples thereof include monomers having a water-soluble group such as an amide group, a hydroxyl group, a carboxyl group, a carboxylic acid ester group, and a sulfonic acid group.

Examples of the water-soluble polymer compound (component C) contained in the additive aqueous solution include water-soluble polymer compounds containing structural units derived from polyamide, cellulose derivatives, polyvinyl alcohol polymers, and acrylamide derivatives. Examples of the polyamide include polyvinyl pyrrolidone, polyacrylamide, polyoxazoline, polydimethylacrylamide, polydiethylacrylamide, polyisopropylacrylamide, polyhydroxyethylacrylamide and the like. Examples of cellulose derivatives include carboxymethyl cellulose, hydroxyethyl cellulose (HEC), hydroxyethyl methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl ethyl cellulose, and carboxymethyl ethyl cellulose. Examples of the polyvinyl alcohol polymer include polyvinyl alcohol (PVA), alkylene oxide-modified PVA, cation-modified PVA, anion-modified PVA, and alkyl-modified PVA. Examples of the water-soluble polymer compound containing a structural unit derived from an acrylamide derivative include a water-soluble polymer compound containing 75% by mass or more of the structural unit I represented by the following general formula (1). However, in the following general formula (1), R ¹ is a hydroxyalkyl group having 1 to 2 carbon atoms. The monomer that is the supply source of the structural unit I represented by the general formula (1) is an acrylamide derivative such as N-hydroxyethylacrylamide (HEAA) or N-hydroxymethylacrylamide (HMAA). These can be used singly or in combination of two or more. Among these monomers, HEAA is preferable from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer.

  With respect to a water-soluble polymer compound containing a structural unit derived from an acrylamide derivative, “containing at least 75 mass% of the structural unit I” means that the mass of the structural unit I in one molecule of the water-soluble polymer compound is water-soluble. It means 75% or more of the weight average molecular weight (Mw) of the polymer compound. Further, in this specification, the content (% by mass) of the structural unit I occupying in all the structural units constituting the water-soluble polymer compound may be reacted in all steps of the synthesis of the water-soluble polymer compound depending on the synthesis conditions. A value calculated from the amount (% by mass) of the compound for introducing the structural unit I charged in the reaction tank in the compound for introducing all the structural units charged in the tank may be used. .

  The proportion of the structural unit I in all the structural units of the water-soluble polymer compound including the structural unit derived from the acrylamide derivative is 75 from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. It is at least 80% by mass, more preferably at least 90% by mass, even more preferably at least 100% by mass, and even more preferably at least 100% by mass.

  The water-soluble polymer compound containing a structural unit derived from an acrylamide derivative may contain a structural unit other than the structural unit I as long as the effect of the present invention is exhibited. When a structural unit other than the structural unit I (also referred to as “structural unit II”) is included, the structural unit other than the structural unit I reduces the surface defects (LPD) and surface roughness (haze) of the silicon wafer. From the viewpoint, at least one monomer selected from the group consisting of N-isopropylacrylamide (NIPAM), acrylic acid (AA), methacrylic acid (MAA), vinylpyrrolidone (VP), dimethylacrylamide (DMAA) and diethylacrylamide (DEAA) Is preferable, and N-isopropylacrylamide (NIPAM) is more preferable.

  In the case where the water-soluble polymer compound is a copolymer containing the structural unit I and the structural unit II represented by the general formula (1), the structural unit in the copolymer of the structural unit I and the structural unit II The arrangement may be block or random.

  Specific examples of the water-soluble polymer compound include HEAA homopolymer, HMAA homopolymer, HEAA / HMAA copolymer, HEAA / NIPAM copolymer, HMAA / NIPAM copolymer, HEAA / HMAA / NIPAM. Copolymer of HEAA and AA, copolymer of HEAA and MAA, copolymer of HEAA and VP, copolymer of HEAA and DMAA, copolymer of HEAA and DEAA, copolymer of HMAA and AA A homopolymer or copolymer containing a structural unit derived from an acrylamide derivative such as a polymer, a copolymer of HMAA and MAA, a copolymer of HMAA and VP, a copolymer of HMAA and DMAA, or a copolymer of HMAA and DEAA. Polymers may be used, and these may be used alone or in combination of two or more. From the viewpoint of reducing surface defects of silicon wafers, HE may be used. A homopolymer, HMAA homopolymer, HEAA / HMAA copolymer, HEAA / NIPAM copolymer, HMAA / NIPAM copolymer, and HEAA / HMAA / NIPAM copolymer At least one polymer is preferred, at least one polymer selected from the group consisting of HEAA homopolymer, HMAA homopolymer, and a copolymer of HEAA and HMAA is more preferred, and HEAA homopolymer is more preferred. .

  These water-soluble polymer compounds may be used in a mixture of two or more at any ratio. Among these water-soluble polymer compounds, from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of silicon wafers, polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, polyethylene glycol, HEAA homopolymer, and At least one water-soluble polymer compound selected from the group consisting of a copolymer of NIPAM and acrylamide (AAm) is preferred, and a group consisting of polyvinyl alcohol, hydroxyethyl cellulose, HEAA homopolymer, and a copolymer of NIPAM and AAm More preferable is at least one water-soluble polymer compound selected from the group consisting of:

  The weight average molecular weight of polyvinyl alcohol is preferably 10,000 or more, more preferably 15,000 or more, and further preferably 20,000 or more, from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. From the viewpoint of suppressing aggregation of silica particles, it is preferably 150,000 or less, more preferably 100,000 or less, and still more preferably 80,000 or less. The weight average molecular weight of polyvinyl alcohol is measured by the method described in Examples described later.

  The weight average molecular weight of polyvinylpyrrolidone is preferably 10,000 or more, more preferably 30,000 or more, and still more preferably 200,000 or more, from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. From the viewpoint of suppressing aggregation of silica particles, it is preferably 1 million or less, more preferably 700,000 or less, and still more preferably 600,000 or less. The weight average molecular weight of polyvinylpyrrolidone is measured by the method described in the examples described later.

  The weight average molecular weight of hydroxyethyl cellulose is preferably 100,000 or more, more preferably 200,000 or more, and further preferably 240,000 or more from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. From the viewpoint of suppressing aggregation of silica particles, it is preferably 1.5 million or less, more preferably 1.1 million or less, and still more preferably 900,000 or less. The weight average molecular weight of HEC is measured by the method described in Examples below.

  The weight average molecular weight of the HEAA homopolymer is preferably 50,000 or more, more preferably 100,000 or more, still more preferably 200,000 or more, from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. Further, more preferably 300,000 or more, still more preferably 400,000 or more, and from the viewpoint of suppressing aggregation of silica particles, preferably 2 million or less, more preferably 1.5 million or less, still more preferably 1 million or less, even more Preferably it is 900,000 or less, More preferably, it is 800,000 or less. The weight average molecular weight of the HEAA homopolymer is measured by the method described in Examples below.

  The weight average molecular weight of the copolymer of NIPAM and AAm is preferably 50,000 or more, more preferably 100,000 or more, more preferably from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. It is 200,000 or more, still more preferably 300,000 or more. From the viewpoint of suppressing aggregation of silica particles, it is preferably 1,000,000 or less, more preferably 800,000 or less, and still more preferably 600,000 or less. The weight average molecular weight of the copolymer of NIPAM and AAm is measured by the method described in the examples below.

  The content of the water-soluble polymer compound (component C) contained in the additive aqueous solution is preferably 0.5% by mass or more, more preferably 1% by mass, from the viewpoint of economy such that production and transportation costs can be reduced. From the viewpoint of improving storage stability, it is preferably 20% by mass or less, more preferably 15% by mass or less, and further preferably 12% by mass or less.

  The condition of the aqueous medium contained in the aqueous additive solution may be the same as that of the aqueous medium contained in the silica particle dispersion.

  About polishing liquid composition obtained by mixing silica particle dispersion and additive aqueous solution, mass ratio of silica particles (component A) and water-soluble polymer compound (component C) (mass of water-soluble polymer compound / silica) The mass of the particles is preferably 0.005 or more, more preferably 0.0075 or more, still more preferably 0.009 or more, from the viewpoint of improving the dispersibility of the silica particles and reducing the surface defects of the silicon wafer. More preferably 0.015 or more, preferably 1.0 or less, more preferably 0.8 or less, still more preferably 0.6 or less, still more preferably 0.4 or less, and even more preferably 0.3 or less. It is.

  The pH at 25 ° C. of a liquid mixture (polishing liquid composition) used for polishing a silicon wafer to be polished and obtained by mixing a silica particle dispersion and an aqueous additive solution constituting the polishing liquid composition and its diluted liquid is From the viewpoint of reducing the surface roughness (haze), it is preferably 8 or more, more preferably 9 or more, still more preferably 10 or more, preferably 13 or less, more preferably 12 or less, still more preferably 11 or less. . The pH can be adjusted by appropriately adding a pH adjusting agent (for example, ammonia). Here, pH at 25 ° C. can be measured using a pH meter (for example, Toa Denpa Kogyo Co., Ltd., HM-30G), and is a value one minute after the electrode is immersed in the polishing liquid composition.

[Polyoxyalkylene compound (component D)]
The aqueous additive solution may further contain a polyoxyalkylene compound. The polyoxyalkylene compound is adsorbed on the silicon wafer to be polished. Therefore, the polyoxyalkylene compound suppresses the corrosion of the wafer surface by the basic compound, and imparts wettability to the wafer surface, thereby preventing the adhesion of particles to the wafer surface, which is considered to be caused by drying of the wafer surface. Acts to suppress. Further, in the cleaning process of the polished silicon wafer, the polyoxyalkylene compound weakens the interaction that occurs between the silica particles and the silicon wafer. Therefore, it is considered that the polyoxyalkylene compound, together with the water-soluble polymer compound, promotes the reduction of surface roughness (haze) and surface defects (LPD).

  The polyoxyalkylene compound (component D) is a polyhydric alcohol alkylene oxide adduct, and is a polyhydric alcohol derivative obtained by addition polymerization of an alkylene oxide such as ethylene oxide or propylene oxide to a polyhydric alcohol. The polyoxyalkylene compound contains at least one alkyleneoxy group selected from the group consisting of an ethyleneoxy group and a propyleneoxy group.

  The number of hydroxyl groups of the polyhydric alcohol that is the source (raw material) of the polyoxyalkylene compound (component D) is determined from the viewpoint of increasing the adsorption strength of the polyoxyalkylene compound to the surface of the silicon wafer, surface defects (LPD) and surface roughness of the silicon wafer. From the viewpoint of reducing the haze, the number is preferably 2 or more, and from the viewpoint of ensuring the polishing rate, preferably 10 or less, more preferably 8 or less, still more preferably 6 or less, and still more preferably. 4 or less.

  Specific examples of the polyoxyalkylene compound (component D) include alkylene glycol alkylene oxide adducts such as polyethylene glycol (PEG) and polypropylene glycol, glycerin alkylene oxide adducts, pentaerythritol alkylene oxide adducts, and the like. Among these, an ethylene glycol alkylene oxide adduct is preferable.

  The polyoxyalkylene compound (component D) contains at least one alkyleneoxy group selected from the group consisting of an ethyleneoxy group (EO) and a propyleneoxy group (PO), but has a surface defect (LPD) and a surface of a silicon wafer. From the viewpoint of reducing roughness (haze), the alkyleneoxy group contained in the polyoxyalkylene compound is preferably composed of at least one alkyleneoxy group selected from the group consisting of EO and PO, and more preferably composed of EO. When the polyoxyalkylene compound contains both EO and PO, the arrangement of EO and PO may be block or random.

The weight average molecular weight of the polyoxyalkylene compound (component D) is preferably 500 or more from the viewpoint of increasing the adsorption amount of the polyoxyalkylene compound to the polished silicon wafer and reducing the surface roughness (haze). Preferably it is 700 or more, more preferably 900 or more. From the viewpoint of increasing the amount of adsorption of the polyoxyalkylene compound to the silica particles and reducing the surface roughness (haze), preferably 250,000 or less, more preferably 100,000 or less, more preferably 20,000 or less, and even more preferably 10,000 or less. The weight average molecular weight of the polyoxyalkylene compound can be calculated based on a peak in a chromatogram obtained by applying a gel permeation chromatography (GPC) method under the following conditions.
<Measurement condition>
Equipment: HLC-8320 GPC (Tosoh Corporation, detector integrated type)
Column: GMPWXL + GMPWXL (anion)
Eluent: 0.2M phosphate buffer / CH ₃ CN = 9/1
Flow rate: 0.5ml / min
Column temperature: 40 ° C
Detector: RI Detector Reference material: Monodispersed polyethylene glycol with known molecular weight

  In the polishing composition obtained by mixing the silica particle dispersion and the aqueous additive solution, the mass ratio of the polyoxyalkylene compound (component D) to the silica particles (component A) (mass of polyoxyalkylene compound / silica particles) From the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer, it is preferably 0.00004 or more, more preferably 0.0012 or more, and still more preferably 0.0020 or more. , Preferably 0.02 or less, more preferably 0.0080 or less, still more preferably 0.0072 or less.

  The mass ratio of the water-soluble polymer compound (component C) and the polyoxyalkylene compound (component D) contained in the aqueous additive solution (the mass of the water-soluble polymer compound / the mass of the polyoxyalkylene compound) is the surface defect of the silicon wafer. From the viewpoint of reducing (LPD) and surface roughness (haze), it is preferably 1 or more, more preferably 3 or more, still more preferably 5 or more, preferably 500 or less, more preferably 200 or less, still more preferably 100. Hereinafter, it is still more preferably 60 or less, and still more preferably 40 or less.

[Other optional ingredients]
In the aqueous additive solution, as long as the effect of the present invention is not hindered, as an optional component other than the polyoxyalkylene compound (component D), a water-soluble polymer compound other than the water-soluble polymer compound, a pH adjuster, At least one optional component selected from preservatives, alcohols, chelating agents, and nonionic surfactants may be included.

<Preservative>
Preservatives include benzalkonium chloride, benzethonium chloride, 1,2-benzisothiazolin-3-one, (5-chloro-) 2-methyl-4-isothiazolin-3-one, hydrogen peroxide, or hypochlorite Examples include acid salts.

<Alcohols>
Examples of alcohols include methanol, ethanol, propanol, butanol, isopropyl alcohol, 2-methyl-2-propanool, ethylene glycol, propylene glycol, polyethylene glycol, and glycerin. The content of the alcohol is preferably 0.1 to 5% by mass in a polishing composition or a diluted solution obtained by diluting the polishing composition with an aqueous medium.

<Chelating agent>
Chelating agents include: ethylenediaminetetraacetic acid, sodium ethylenediaminetetraacetate, nitrilotriacetic acid, sodium nitrilotriacetate, ammonium nitrilotriacetate, hydroxyethylethylenediaminetriacetic acid, sodium hydroxyethylethylenediaminetriacetate, triethylenetetraminehexaacetic acid, triethylenetetramine Examples include sodium hexaacetate. The content of the chelating agent is preferably 0.01 to 1% by mass in a polishing composition or a diluted solution obtained by diluting the polishing composition with an aqueous medium.

<Nonionic surfactant>
Nonionic surfactants include polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbit fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl phenyl ether, Examples include polyethylene glycol types such as oxyalkylene (cured) castor oil, polyhydric alcohol types such as sucrose fatty acid ester, polyglycerin alkyl ether, polyglycerin fatty acid ester, alkylglycoside, and fatty acid alkanolamide.

  Next, an example of a method for preparing the polishing liquid composition will be described.

[Method for preparing silica particle dispersion]
The silica particle dispersion is obtained by passing through a ripening step in which a liquid mixture obtained by mixing silica particles (component A), a basic compound (component B), and an aqueous medium is maintained at a predetermined temperature for a predetermined time. . Mixing of the silica particles (component A), the basic compound (component B) and the aqueous medium can be performed using, for example, a stirrer such as a homomixer, a homogenizer, an ultrasonic disperser, a wet ball mill, or a bead mill. . When coarse particles generated by aggregation of silica particles or the like are contained in an aqueous medium, it is preferable to remove the coarse particles by centrifugation or filtration using a filter.

  In the aging step, the predetermined temperature is 10 ° C. or more from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer, but from the viewpoint of shortening the aging time and improving productivity. Is 30 ° C. or higher, and from the viewpoint of storage stability, it is 80 ° C. or lower, preferably 60 ° C. or lower. The predetermined time is 1 day (1 day (24 hours) ± 6 hours) or more, preferably 3 days (3 days) from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. (72 hours) ± 6 hours) or more, more preferably 5 days (5 days (120 hours) ± 6 hours) or more, and preferably 30 days (30 days (720 hours) ± 6 from the viewpoint of improving productivity. Time) or less, more preferably 8 days (8 days (192 hours) ± 6 hours) or less. The predetermined time is more preferably 12 days (12 days (288 hours) ± 6 hours) or more, and still more preferably, from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. 28 days (28 days (672 hours) ± 6 hours) or more, more preferably 40 days (40 days (960 hours) ± 6 hours) or more, more preferably 60 days (60 days (1440 hours) ± 6 hours) or more More preferably, it is 80 days (80 days (1920 hours) ± 6 hours) or more. In the aging step, when the predetermined temperature is 18 ° C. or higher and 32 ° C. or lower, the predetermined time is preferably 3 days (from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer). 3 days (72 hours) ± 6 hours) or more, more preferably 5 days (5 days (120 hours) ± 6 hours) or more, more preferably 12 days (12 days (288 hours) ± 6 hours) or more, even more Preferably 28 days (28 days (672 hours) ± 6 hours) or more, more preferably 40 days (40 days (960 hours) ± 6 hours) or more, more preferably 60 days (60 days (1440 hours) ± 6 hours) ) Or more, more preferably 80 days (80 days (1920 hours) ± 6 hours) or more. The “predetermined time” is counted from the time when the components of the silica particle dispersion are mixed, and the time elapsed from the time before the mixing with the aqueous additive solution is started. Accordingly, the “predetermined time” includes not only the time stored in a warehouse or the like but also the transportation time when transportation or the like is performed. In the present application, the predetermined time represented by the number of days means the number of days × 24 hours ± 6 hours. For example, the predetermined time “1 day” means 24 hours ± 6 hours.

  Aging of a mixed liquid obtained by mixing silica particles (component A), a basic compound (component B), and an aqueous medium is possible from the viewpoint of reducing surface defects (LPD) and surface roughness (haze). It is preferable that the process be performed in a state where the container is filled so that air and light do not enter.

[Method for preparing additive aqueous solution]
The aqueous additive solution can be prepared by blending a water-soluble polymer compound (component C), an aqueous medium, and optional components as necessary.

[Method for preparing polishing composition]
It is prepared by mixing the above-described silica particle dispersion of the polishing composition of the present invention and an aqueous additive solution. The method for preparing the polishing composition is not particularly limited, but from the viewpoint of improving the dispersion stability of the silica particles, it is preferable to add the silica particle dispersion to the aqueous additive solution and mix them. Furthermore, from the viewpoint of enhancing the dispersibility of the silica particles, it is preferable to add the silica particle dispersion to the aqueous solution of the additive while stirring the aqueous additive solution and mix them. Moreover, it can also be prepared by adding an aqueous medium separately from the silica particle dispersion and the aqueous additive solution. A general dispersion or particle removal method should be used for the purpose of efficiently and economically removing coarse particles contained in the silica particle dispersion or polishing liquid composition during or after the preparation of the polishing liquid composition. Can do.

<Polishing method of silicon wafer to be polished, manufacturing method of semiconductor substrate>
One aspect of a polishing method for a silicon wafer to be polished of the present invention (hereinafter sometimes referred to as “the polishing method of the present invention”) and a method of manufacturing a semiconductor substrate of the present invention (hereinafter referred to as “the manufacturing method of the present invention”) In another embodiment, the step of polishing a silicon wafer to be polished using the polishing composition of the present invention as it is or using the polishing composition obtained by diluting the polishing composition of the present invention with an aqueous medium. including. In another aspect of the polishing method of the present invention and another aspect of the manufacturing method of the present invention, the silica particle dispersion (first liquid) and the aqueous additive solution (the aqueous solution of the composition for preparing the polishing liquid composition of the present invention) After mixing with the second liquid), if necessary, it is diluted with an aqueous medium, or if necessary, either one of the silica particle dispersion (first liquid) and the aqueous additive solution (second liquid) or The method includes a step of polishing a silicon wafer to be polished using a polishing composition obtained by diluting both with an aqueous medium and then mixing them. Each amount of the silica particle dispersion and the aqueous additive solution may be appropriately adjusted according to the target surface defects (LPD) and surface roughness (haze) of the polished silicon wafer to be polished.

  For example, a one-component polishing composition obtained by mixing silica particles, a basic compound, a water-soluble polymer compound, and an aqueous medium has a predetermined storage time and a predetermined temperature after mixing the components. If it is used directly for polishing without passing through the aging step, the surface defects (LPD) and the surface roughness (haze) are deteriorated. In the polishing method of the present invention and the production method of the present invention, a silica particle dispersion containing silica particles whose hydration layer is highly stabilized, or freeze-dried BET specific surface area is divided by the BET specific surface area of air-dried silica particles. A polishing composition prepared using a silica particle dispersion having a value of 1.3 or more and 10 or less (including a polishing composition prepared using the polishing composition preparation kit of the present invention). Since it is used for polishing a silicon wafer to be polished, surface defects (LPD) and surface roughness (haze) can be reduced even if these are immediately used for polishing a silicon wafer to be polished after preparation of the polishing composition.

  In the process of polishing the silicon wafer to be polished, a lapping process (rough polishing) for flattening the silicon wafer obtained by slicing a silicon single crystal ingot into a thin disk shape, and etching the lapped silicon wafer After that, there is a final polishing process for mirror-finishing the silicon wafer surface. The polishing composition of the present invention is more preferably used in the above-described finish polishing step.

Wherein in the step of polishing the silicon wafer, for example, sandwiching a polished silicon wafer with surface plate pasting a polishing pad, polishing the silicon wafer at 30 gf / cm ² or more 200 gf / cm ² or less of polishing pressure .

The polishing pressure refers to the pressure of the surface plate applied to the surface to be polished of the silicon wafer to be polished at the time of polishing. Polishing pressure is, in view of polishing economically improve the polishing rate is preferably 30 gf / cm ² or more, more preferably 40 gf / cm ² or more, more preferably 50 gf / cm ² or more, 55gf / cm ² or more Even more preferred. Moreover, to improve the surface quality, in view of and to relax the residual stress of the polished, the polishing pressure is preferably from 200 gf / cm ² or less, more preferably 180gf / cm ² or less, more preferably 160 gf / cm ² or less is there.

  The production method of the present invention and the polishing method of the present invention further include a step of cleaning the polished silicon wafer after the step of polishing the silicon wafer to be polished using the polishing composition.

  The manufacturing method of the semiconductor substrate of this invention includes the process of grind | polishing a to-be-polished silicon wafer using the said polishing liquid composition kit for silicon wafers. Here, “using the polishing composition composition for silicon wafer” means that the silica particle dispersion liquid (first liquid) and the aqueous additive solution (second liquid) of the “polishing composition kit for silicon wafer” described above are used. After mixing, if necessary, dilute with an aqueous medium, or if necessary, dilute either or both of the silica particle dispersion (first liquid) and the aqueous additive solution (second liquid) with an aqueous medium. And then using a polishing composition obtained by mixing them.

  The polishing method for a silicon wafer to be polished according to the present invention includes a step of polishing the silicon wafer to be polished using the polishing composition composition kit for silicon wafer. Here, “using the polishing composition composition for silicon wafer” means that the silica particle dispersion liquid (first liquid) and the aqueous additive solution (second liquid) of the “polishing composition kit for silicon wafer” described above are used. After mixing, if necessary, dilute with an aqueous medium, or if necessary, dilute either or both of the silica particle dispersion (first liquid) and the aqueous additive solution (second liquid) with an aqueous medium. And then using a polishing composition obtained by mixing them.

  The present invention further discloses the following <1> to <48>.

<1> A polishing composition for a silicon wafer obtained by mixing a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. There,
In the case where the light transmittance at a wavelength of 600 nm of the silica particle dispersion is any of the silica particle content of 5% by mass or more and 20% by mass or less, 5.0% or more, more preferably 5% or more, More preferably 8.0% or more, still more preferably 8% or more, still more preferably 11% or more, 30% or less, preferably 24% or less, more preferably 16% or less. Liquid composition.
<2> The polishing composition for a silicon wafer according to <1>, wherein the silica particle dispersion has a pH of 9 or more and 11 or less at 25 ° C.
<3> A polishing composition for a silicon wafer obtained by mixing a silica particle dispersion containing silica particles, a basic compound, and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. There,
The silica particle dispersion has a light transmittance at a wavelength of 600 nm, the silica particle dispersion has a pH of 9 to 11 at 25 ° C., preferably pH 10 ± 0.3, and the silica particle content is 10 mass%. In the case of 15% by mass or less, preferably 10% by mass, 5.0% or more, more preferably 5% or more, still more preferably 8.0% or more, still more preferably 8% or more, and even more preferably A polishing composition for a silicon wafer, which is 11% or more and 30% or less, preferably 24% or less, more preferably 16% or less.
<4> A polishing composition for a silicon wafer obtained by mixing a silica particle dispersion containing silica particles, a basic compound, and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. There,
The silica particle dispersion has a light transmittance at a wavelength of 600 nm of 5.0% or more and 30% or less, the silica particle dispersion has a pH at 25 ° C. of 9 or more and 11 or less, and the content of the silica particles is A polishing composition for a silicon wafer, which is 10% by mass or more and 15% by mass or less.
<5> A polishing composition for a silicon wafer obtained by mixing a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. There,
BET ratio obtained by dividing the BET specific surface area of freeze-dried silica particles obtained by freeze-drying the silica particle dispersion by the BET specific surface area of air-dried silica particles obtained by air-drying the silica particle dispersion. The surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) is 1.3 or more, preferably 1.5 or more, more preferably 2.0 or more, and 10 or less, preferably 5 A polishing composition for silicon wafers of 0.0 or less, more preferably 3.0 or less.
<6> The amount of silanol groups per unit mass of the silica particles after lyophilization is preferably 2.1 mmol / g or more, more preferably 2.3 mmol / g or more, and even more preferably 2.4 mmol / g or more. Preferably, it is 10 mmol / g or less, More preferably, it is 5.0 mmol / g or less, More preferably, it is 3.0 mmol / g or less, The polishing liquid composition for silicon wafers as described in <5>.
<7> The porosity of the surface of the silica particles after lyophilization is preferably 1.5% or more, more preferably 4.0% or more, still more preferably 6.0% or more, and preferably 30% or less. The polishing composition for silicon wafers according to <5> or <6>, more preferably 20% or less, still more preferably 15% or less.
<8> The BET specific surface area of the freeze-dried silica particles are preferably 95 m ² / g or more, more preferably 110m ² / g or more, more preferably at 150 meters ² / g or more, preferably 400 meters ² / g or less, more preferably 300 meters ² / g or less, more preferably at most 250 meters ² / g, a silicon wafer for the polishing liquid composition according to any one of <7> to <5>.
<9> The water-soluble polymer compound is preferably at least one selected from the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, polyethylene glycol, polyoxyethylene, HEAA homopolymer, and a copolymer of NIPAM and AAm. Including at least one water-soluble polymer compound selected from the group consisting of polyvinyl alcohol, hydroxyethyl cellulose, HEAA homopolymer, and a copolymer of NIPAM and AAm, The polishing composition for silicon wafers according to any one of <1> to <8>.
<10> The weight average molecular weight of the polyvinyl alcohol is preferably 10,000 or more, more preferably 15,000 or more, still more preferably 20,000 or more, preferably 150,000 or less, more preferably 100,000 or less, The polishing composition for silicon wafers according to <9>, preferably 80,000 or less.
<11> The polyvinyl pyrrolidone preferably has a weight average molecular weight of 10,000 or more, more preferably 30,000 or more, still more preferably 200,000 or more, preferably 1,000,000 or less, more preferably 700,000 or less, and still more preferably. The polishing composition for silicon wafers according to <9>, which is 600,000 or less.
<12> The weight average molecular weight of the hydroxyethyl cellulose is preferably 100,000 or more, more preferably 200,000 or more, further preferably 240,000 or more, preferably 1.5 million or less, more preferably 1.1 million or less, and still more preferably. The polishing composition for silicon wafers according to <9>, which is 900,000 or less.
<13> The weight average molecular weight of the HEAA homopolymer is preferably 50,000 or more, more preferably 100,000 or more, still more preferably 200,000 or more, still more preferably 300,000 or more, and even more preferably 400,000 or more. The silicon wafer according to <9>, preferably 2 million or less, more preferably 1.5 million or less, still more preferably 1 million or less, still more preferably 900,000 or less, and even more preferably 800,000 or less. Polishing liquid composition.
<14> The weight average molecular weight of the copolymer of NIPAM and AAm is preferably 50,000 or more, more preferably 100,000 or more, still more preferably 200,000 or more, still more preferably 300,000 or more, preferably 100 The polishing composition for a silicon wafer according to the above <9>, which is 10,000 or less, more preferably 800,000 or less, and still more preferably 600,000 or less.
<15> Preferably, the polishing composition for a silicon wafer according to any one of <1> to <14>, wherein the aqueous additive solution further contains a polyoxyalkylene compound.
<16> The average primary particle size of the silica particles is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 15 nm or more, still more preferably 20 nm or more, preferably 50 nm or less, more preferably 45 nm or less, More preferably, it is 40 nm or less, The polishing composition for silicon wafers in any one of said <1> to <15>.
<17> The mass ratio of the silica particles (component A) to the water-soluble polymer compound (component C) (mass of water-soluble polymer compound / mass of silica particles) is preferably 0.005 or more, more preferably 0.0075 or more, more preferably 0.009 or more, still more preferably 0.015 or more, preferably 1.0 or less, more preferably 0.8 or less, still more preferably 0.6 or less, and even more preferably The polishing composition for silicon wafers according to any one of <1> to <16>, wherein is 0.4 or less, and even more preferably 0.3 or less.
<18> The pH of the polishing composition at 25 ° C. is preferably 8 or higher, more preferably 9 or higher, still more preferably 10 or higher, preferably 13 or lower, more preferably 12 or lower, still more preferably 11 or lower. The polishing composition for a silicon wafer according to any one of <1> to <17>, wherein
<19> A silica particle dispersion (first liquid) containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution (second liquid) containing a water-soluble polymer compound and an aqueous medium,
The transmittance of light having a wavelength of 600 nm of the silica particle dispersion (first liquid) is more preferably 5.0% or more when the content of the silica particles is 5% by mass or more and 20% by mass or less. Is at least 5%, more preferably at least 8.0%, even more preferably at least 8%, even more preferably at least 11%, at most 30%, preferably at most 24%, more preferably at most 16%. A polishing composition kit for silicon wafers.
<20> The polishing composition composition for a silicon wafer according to <19>, wherein the silica particle dispersion has a pH at 25 ° C. of 9 or more and 11 or less.
<21> A silica particle dispersion (first liquid) containing silica particles, a basic compound, and an aqueous medium, and an aqueous additive solution (second liquid) containing a water-soluble polymer compound and an aqueous medium,
The silica particle dispersion (first liquid) has a light transmittance of a wavelength of 600 nm, and the silica particle dispersion has a pH of 9 to 11 at 25 ° C., preferably pH 10 ± 0.3. In the case where the amount is 10% by mass or more and 15% by mass or less, preferably 10% by mass, 5.0% or more, more preferably 5% or more, still more preferably 8.0% or more, and even more preferably 8% or more. Even more preferably, it is 11% or more, 30% or less, preferably 24% or less, more preferably 16% or less, a polishing composition composition for a silicon wafer.
<22> A silica particle dispersion (first liquid) containing silica particles, a basic compound, and an aqueous medium, and an aqueous additive solution (second liquid) containing a water-soluble polymer compound and an aqueous medium,
BET ratio obtained by dividing the BET specific surface area of freeze-dried silica particles obtained by freeze-drying the silica particle dispersion by the BET specific surface area of air-dried silica particles obtained by air-drying the silica particle dispersion. The surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) is 1.3 or more, preferably 1.5 or more, more preferably 2.0 or more, and 10 or less, preferably 5 A polishing composition composition kit for silicon wafers of 0.0 or less, more preferably 3.0 or less.
<23> The amount of silanol groups per unit mass of the freeze-dried silica particles is preferably 2.1 mmol / g or more, more preferably 2.3 mmol / g or more, still more preferably 2.4 mmol / g or more, <10> The polishing composition composition for a silicon wafer according to <22>, wherein is 10 mmol / g or less, more preferably 5.0 mmol / g or less, and still more preferably 3.0 mmol / g or less.
<24> The porosity on the surface of the freeze-dried silica particles is preferably 1.5% or more, more preferably 4.0% or more, still more preferably 6.0% or more, and preferably 30% or less. The polishing composition kit for a silicon wafer according to <22> or <23>, preferably 20% or less, more preferably 15% or less.
<25> The BET specific surface area of the freeze-dried silica particles are preferably 95 m ² / g or more, more preferably 110m ² / g or more, more preferably at 150 meters ² / g or more, preferably 400 meters ² / g or less, more preferably 300 meters ² / g or less, more preferably at most 250 meters ² / g, the polishing composition kit silicon wafer according to any one of <24> to <22>.
<26> The water-soluble polymer compound is preferably at least selected from the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, polyethylene glycol, polyoxyethylene, HEAA homopolymer, and a copolymer of NIPAM and AAm. Containing one water-soluble polymer compound, more preferably containing at least one water-soluble polymer compound selected from the group consisting of polyvinyl alcohol, hydroxyethyl cellulose, HEAA homopolymer, and a copolymer of NIPAM and AAm, The polishing composition composition for a silicon wafer according to any one of <19> to <25>.
<27> The weight average molecular weight of the polyvinyl alcohol is preferably 10,000 or more, more preferably 15,000 or more, still more preferably 20,000 or more, preferably 150,000 or less, more preferably 100,000 or less, The polishing composition composition kit for silicon wafers according to <26>, preferably 80,000 or less.
<28> The weight average molecular weight of the polyvinylpyrrolidone is preferably 10,000 or more, more preferably 30,000 or more, still more preferably 200,000 or more, preferably 1,000,000 or less, more preferably 700,000 or less, and still more preferably. The polishing composition composition kit for silicon wafers according to <26>, which is 600,000 or less.
<29> The weight average molecular weight of the hydroxyethyl cellulose is preferably 100,000 or more, more preferably 200,000 or more, still more preferably 240,000 or more, preferably 1.5 million or less, more preferably 1.1 million or less, and still more preferably. The polishing composition kit for silicon wafers according to <26>, which is 900,000 or less.
<30> The weight average molecular weight of the HEAA homopolymer is preferably 50,000 or more, more preferably 100,000 or more, still more preferably 200,000 or more, still more preferably 300,000 or more, and even more preferably 400,000 or more. The silicon wafer according to <26>, preferably 2 million or less, more preferably 1.5 million or less, still more preferably 1 million or less, still more preferably 900,000 or less, and even more preferably 800,000 or less. Polishing liquid composition kit.
<31> The weight average molecular weight of the copolymer of NIPAM and AAm is preferably 50,000 or more, more preferably 100,000 or more, still more preferably 200,000 or more, still more preferably 300,000 or more, preferably 100 The polishing composition composition for a silicon wafer according to the above <26>, which is 10,000 or less, more preferably 800,000 or less, and still more preferably 600,000 or less.
<32> The polishing composition composition for a silicon wafer according to any one of <19> to <31>, wherein the aqueous additive solution further contains a polyoxyalkylene compound.
<33> The content of silica particles contained in the silica particle dispersion is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more, and preferably 25% by mass or less. More preferably, it is 20 mass% or less, More preferably, it is 15 mass% or less, The polishing composition composition for silicon wafers in any one of said <19> to <32>.
<34> The content of the basic compound (component B) contained in the silica particle dispersion is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.5% by mass. It is above, Preferably it is 5 mass% or less, More preferably, it is 4 mass% or less, More preferably, it is 3 mass% or less, The polishing liquid composition for silicon wafers in any one of said <19> to <33> kit.
<35> The mass ratio of the silica particles to the basic compound (silica particles / basic compound) contained in the silica particle dispersion is preferably 0.6 or more, more preferably 1 or more, and still more preferably 3 or more. Preferably, it is 500 or less, More preferably, it is 200 or less, More preferably, it is 100 or less, The polishing liquid composition kit for silicon wafers in any one of said <19> to <34>.
<36> The content of the water-soluble polymer compound contained in the aqueous additive solution is preferably 0.5% by mass or more, more preferably 1% by mass or more, and still more preferably 1.5% by mass or more. The polishing composition kit for silicon wafers according to any one of <19> to <35>, wherein is 20% by mass or less, more preferably 15% by mass or less, and still more preferably 12% by mass or less.
<37> A method for producing a polishing composition for a silicon wafer comprising silica particles, a basic compound, a water-soluble polymer compound, and an aqueous medium,
Mixing the water-soluble polymer compound and the aqueous medium to obtain an aqueous additive solution;
A mixed solution having a pH of 9 or more and 11 or less at 25 ° C. obtained by mixing the silica particles, the basic compound and the aqueous medium is 10 ° C. or more, preferably 30 ° C. or more and 80 ° C. or less, preferably 60 ° C. 1 day (1 day (24 hours) ± 6 hours) or more, preferably 3 days (3 days (72 hours) ± 6 hours) or more, more preferably 5 days (5 days (120 hours) ± 6 hours) ) Or more, preferably 30 days (30 days (720 hours) ± 6 hours) or less, more preferably 8 days (8 days (192 hours) ± 6 hours) or less to obtain a silica particle dispersion, ,
A method for producing a polishing composition for a silicon wafer, comprising a step of mixing the silica particle dispersion and the aqueous additive solution.
<38> The content of silica particles contained in the silica particle dispersion is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more, and preferably 25% by mass or less. More preferably, it is 20 mass% or less, More preferably, it is 15 mass% or less, The manufacturing method of the polishing liquid composition for silicon wafers as described in said <37>.
<39> A method for producing a polishing composition composition kit for a silicon wafer according to any one of <19> to <36>,
A step of mixing a water-soluble polymer compound and an aqueous medium to obtain an aqueous additive solution;
A mixed solution having a pH of 9 or more and 11 or less at 25 ° C. obtained by mixing silica particles, a basic compound and an aqueous medium is 10 ° C. or more, preferably 30 ° C. or more and 80 ° C. or less, preferably 60 ° C. or less. 1 day (1 day (24 hours) ± 6 hours) or more, preferably 3 days (3 days (72 hours) ± 6 hours) or more, more preferably 5 days (5 days (120 hours) ± 6 hours) or more, Preferably 30 days (30 days (720 hours) ± 6 hours) or less, more preferably 8 days (8 days (192 hours) ± 6 hours) or less to obtain a silica particle dispersion. A method for producing a polishing composition kit for a silicon wafer.
<40> The content of silica particles contained in the silica particle dispersion is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more, and preferably 25% by mass or less. More preferably, it is 20 mass% or less, More preferably, it is 15 mass% or less, The manufacturing method of the polishing liquid composition kit for silicon wafers as described in said <39>.
<41> A silica particle dispersion containing silica particles, a basic compound, and an aqueous medium,
In the case where the light transmittance at a wavelength of 600 nm of the silica particle dispersion is any of the silica particle content of 5% by mass or more and 20% by mass or less, 5.0% or more, more preferably 5% or more, More preferably 8.0% or more, still more preferably 8% or more, even more preferably 11% or more, and 30% or less, preferably 24% or less, more preferably 16% or less. .
<42> A silica particle dispersion containing silica particles, a basic compound, and an aqueous medium,
The silica particle dispersion has a light transmittance at a wavelength of 600 nm, the silica particle dispersion has a pH of 9 to 11 at 25 ° C., preferably pH 10 ± 0.3, and the silica particle content is 10 mass%. In the case of 15% by mass or less, preferably 10% by mass, 5.0% or more, more preferably 5% or more, still more preferably 8.0% or more, still more preferably 8% or more, and even more preferably A silica particle dispersion liquid of 11% or more and 30% or less, preferably 24% or less, more preferably 16% or less.
<43> A silica particle dispersion containing silica particles, a basic compound, and an aqueous medium,
BET ratio obtained by dividing the BET specific surface area of freeze-dried silica particles obtained by freeze-drying the silica particle dispersion by the BET specific surface area of air-dried silica particles obtained by air-drying the silica particle dispersion. The surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) is 1.3 or more, preferably 1.5 or more, more preferably 2.0 or more, and 10 or less, preferably 5 A silica particle dispersion liquid of 0.0 or less, more preferably 3.0 or less.
<44> A polishing liquid for silicon wafer, comprising a step of mixing the silica particle dispersion liquid according to any one of <41> to <43>, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. A method for producing the composition.
<45> A method for producing a semiconductor substrate, comprising a step of polishing a silicon wafer to be polished using the polishing composition for a silicon wafer according to any one of <1> to <18>.
<46> A method for polishing a silicon wafer to be polished, comprising a step of polishing the silicon wafer to be polished using the polishing composition for a silicon wafer according to any one of <1> to <18>.
<47> A method for producing a semiconductor substrate, comprising a step of polishing a silicon wafer to be polished using the polishing composition composition for silicon wafer according to any one of <19> to <36>.
<48> A method for polishing a silicon wafer to be polished, comprising a step of polishing the silicon wafer to be polished using the polishing composition composition for silicon wafer according to any one of <19> to <36>.

1. Synthesis of water-soluble polymer compound or details thereof (1) Synthesis of HEAA homopolymer (pHEAA) HEAA homopolymer used in the preparation of the polishing composition of Examples 1-22 and Comparative Examples 1 and 2 below is It was synthesized as follows.

  Hydroxyethyl acrylamide 150 g (1.30 mol manufactured by Kojin Co., Ltd.) was dissolved in 100 g of ion exchange water to prepare an aqueous monomer solution. Separately, 0.035 g of 2,2'-azobis (2-methylpropionamidine) dihydrochloride (polymerization initiator, V-50 1.30 mmol, manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 70 g of ion-exchanged water to obtain a polymerization initiator aqueous solution. Was prepared. After putting 1180 g of ion-exchanged water into a 2 L separable flask equipped with a Dimroth condenser, thermometer, and crescent Teflon (registered trademark) stirring blade, the inside of the separable flask was purged with nitrogen. Next, after raising the temperature in the separable flask to 68 ° C. using an oil bath, the above-prepared monomer aqueous solution and the above polymerization initiator aqueous solution were each stirred for 3.5 hours in the separable flask. It was dripped. After completion of the dropwise addition, the temperature and stirring of the reaction solution were maintained for 4 hours to obtain 1500 g of a colorless and transparent 10% by mass polyhydroxyethylacrylamide (HEAA homopolymer (weight average molecular weight: 720000) aqueous solution.

(2) In Example 23 and Comparative Example 3 below, hydroxyethyl cellulose (HEC, weight average molecular weight 240,000, manufactured by Daicel FineChem) is used as the water-soluble polymer compound. As the polymer compound, polyvinyl pyrrolidone (PVP, weight average molecular weight 360,000, K-60 manufactured by Tokyo Chemical Industry Co., Ltd.) was used. In Example 26 and Comparative Example 6, polyvinyl alcohol (PVA, weight average) was used as the water-soluble polymer compound. A molecular weight of 25,000, PVA105 manufactured by Kuraray Co., Ltd. was used.

(3) Synthesis of copolymer of NIPAM and AAm (acrylamide) (NIPAM / AAm)
The copolymer of NIPAM and AAm used for the preparation of the polishing liquid compositions of Example 25 and Comparative Example 5 was synthesized as follows.

  In a 500 ml separable flask equipped with a thermometer and a 5 cm crescent moon Teflon (registered trademark) stirring blade, 40 g of isopropylacrylamide (0.35 mol manufactured by Kojin), 10 g of acrylamide (0.14 mol manufactured by Wako Pure Chemical Industries), and ion-exchanged water 75 g and 0.028 g of 30% hydrogen peroxide (0.25 mmol, manufactured by Wako Pure Chemical Industries, Ltd.) were added to obtain a solution in which isopropylacrylamide and acrylamide were dissolved in ion-exchanged water. The solution was then bubbled with nitrogen at 50 ml / min for 30 minutes. On the other hand, 0.043 g of L-ascorbic acid (polymerization initiator, 0.25 mmol, manufactured by Wako Pure Chemical Industries, Ltd.) and 24.93 g of ion-exchanged water were mixed in a 50 ml beaker, and L-ascorbic acid was dissolved in the ion-exchanged water. An acid solution was obtained and nitrogen was blown into it at 50 ml / min for 30 minutes. Next, an L-ascorbic acid solution into which nitrogen was blown was dropped into a solution containing isopropylacrylamide and acrylamide in a 500 ml separable flask at 25 ° C. over 30 minutes, and then 25 ° C., 200 rpm (peripheral speed 1.05 m / s). ) For 1 hour. Furthermore, it heated up at 40 degreeC and stirred for 1 hour. After adding 100 ml of ion-exchanged water to the solution in the separable flask, it was dropped into acetone 4L (manufactured by Wako Pure Chemical Industries), and a NIPAM / AAm copolymer (solid) with a weight ratio of NIPAM to AAm of 80:20 ) The obtained solid was dried at 70 ° C./1 KPa or less to obtain 42.7 g of a translucent solid (a copolymer of NIPAM and AAm (weight average molecular weight 400000, yield 85%)).

2. Measurement method of various parameters <Measurement of weight average molecular weight of water-soluble polymer compound>
The weight average molecular weight of the water-soluble polymer compound was calculated based on the peak in the chromatogram obtained by applying the gel permeation chromatography (GPC) method under the following conditions. The weight average molecular weight of HEC is a catalog value.
<Measurement condition>
Equipment: HLC-8320 GPC (Tosoh Corporation, detector integrated type)
Column: GMPWXL + GMPWXL (anion)
Eluent: 0.2M phosphate buffer / CH ₃ CN = 9/1
Flow rate: 0.5ml / min
Column temperature: 40 ° C
Detector: Shodex RI SE-61 Differential refractive index detector Standard material: Monodispersed polyethylene glycol of known molecular weight

<Measurement of water solubility>
The water-solubility of each water-soluble polymer compound was prepared by adjusting a 0.5 g / 100 ml water-soluble polymer compound aqueous solution and visually checking the state according to the following evaluation method.
(Evaluation method)
(1) Pour about 90 ml of water into the screw tube and start stirring at room temperature.
(2) Weigh 0.5 g of the water-soluble polymer compound into the screw tube.
(3) After stirring at room temperature for 3 hours, the temperature is raised to 70 degrees and stirring is continued for 3 hours.
(4) After cooling to room temperature, water is added to make 100 ml.
(5) Visually check the state of the aqueous solution. If it is transparent, it is a water-soluble compound.
All the water-soluble polymer compounds used this time were transparent at 0.5% by weight, and were judged to be water-soluble in the present invention.

<Measurement of average primary particle diameter of abrasive (silica particles)>
The average primary particle diameter (nm) of the abrasive was calculated by the following formula using the specific surface area S (m ² / g) calculated by the BET (nitrogen adsorption) method.
Average primary particle diameter (nm) = 2727 / S

  The specific surface area of the abrasive is subjected to the following [pretreatment], and then approximately 0.1 g of a measurement sample is accurately weighed to 4 digits after the decimal point in a measurement cell, and immediately under the measurement at a specific temperature of 110 ° C. for 30 minutes. After drying, the surface area was measured by a nitrogen adsorption method (BET method) using a specific surface area measuring device (Micromeritic automatic specific surface area measuring device Flowsorb III 2305, manufactured by Shimadzu Corporation).

[Preprocessing]
(A) The slurry-like abrasive is adjusted to pH 2.5 ± 0.1 with an aqueous nitric acid solution.
(B) A slurry-like abrasive adjusted to pH 2.5 ± 0.1 is placed in a petri dish and dried in a hot air dryer at 150 ° C. for 1 hour.
(C) After drying, the obtained sample is finely ground in an agate mortar.
(D) The pulverized sample is suspended in ion exchange water at 40 ° C. and filtered through a membrane filter having a pore size of 1 μm.
(E) The filtrate on the filter is washed 5 times with 20 g of ion exchange water (40 ° C.).
(F) The filter with the filtrate attached is taken in a petri dish and dried in an atmosphere of 110 ° C. for 4 hours.
(G) The dried filtrate (abrasive grains) was taken so as not to be mixed with filter waste, and finely pulverized with a mortar to obtain a measurement sample.

<Average secondary particle diameter of abrasive (silica particles)>
The average secondary particle diameter (nm) of the abrasive is such that the abrasive dispersion is added to ion-exchanged water so that the concentration of the abrasive is 0.25% by mass, and the resulting aqueous dispersion is then disposable sizing cuvette (polystyrene). (10 mm cell manufactured) up to a height of 10 mm from the bottom, and measured using a dynamic light scattering method (device name: Zetasizer Nano ZS, manufactured by Sysmex Corporation).

<Measurement of BET specific surface area of freeze-dried silica particles>
The silica particle dispersion was preliminarily frozen for 8 hours at a freezing temperature of −45 ° C. using a freeze dryer (DFR-5N-B, manufactured by UVLAC Co., Ltd.), and then the freezing temperature of −45 ° C. and a drying pressure of 10 Pa. And lyophilized for 48 hours. The obtained freeze-dried product was finely pulverized using an agate mortar to obtain a measurement sample. About 0.1 g of the obtained measurement sample was precisely weighed to 4 digits after the decimal point in the measurement cell, dried for 30 minutes under an atmosphere of 110 ° C. immediately before the measurement of the specific surface area, and then a specific surface area measurement device (Micromeritic Automatic The specific surface area (m ² / g) of the freeze-dried silica particles was measured by a nitrogen adsorption method (BET method) using a specific surface area measuring apparatus Flowsorb III2305 (manufactured by Shimadzu Corporation).

<Measurement of BET specific surface area of air-dried silica particles>
The silica particle dispersion was air-dried for 48 hours at room temperature (25 ° C.). The obtained dried product was finely pulverized using an agate mortar to obtain a measurement sample. About 0.1 g of the obtained measurement sample was precisely weighed to 4 digits after the decimal point in the measurement cell, dried for 30 minutes under an atmosphere of 110 ° C. immediately before the measurement of the specific surface area, and then a specific surface area measurement device (Micromeritic Automatic The specific surface area (m ² / g) of the air-dried silica particles was measured by a nitrogen adsorption method (BET method) using a specific surface area measuring apparatus Flowsorb III2305 (manufactured by Shimadzu Corporation).

<Measurement of silanol group amount>
The amount of silanol groups per unit mass of the freeze-dried silica particles was measured using a differential type differential thermal balance (TG-DTA) (manufactured by Rigaku Denki Kogyo Co., Ltd., trade name: Thermo Plus TG8120). The freeze-dried silica particles were heated at a rate of 10 ° C./min up to 25 to 700 ° C. under air flow (300 mL / min), and the remainder of the mass measured at 200 ° C. was the SiO ₂ weight (g), 200 The weight loss during heating up to ˜700 ° C. was measured as the mass (g) of water derived from silanol, and the amount of silanol groups (mmol / g) was calculated using the following formula.
Silanol group amount (mmol / g) = (2 × weight of water × 1000/18) / weight of SiO ₂

<Measurement of porosity>
Using a specific surface area / pore distribution measuring device (manufactured by Shimadzu Corporation, trade name: ASAP2020), nitrogen gas adsorption measurement of freeze-dried silica particles was performed by a multipoint method using liquid nitrogen. The sample (freeze-dried silica particles) that was subjected to nitrogen gas adsorption measurement was pretreated by heating at 200 ° C. for 2 hours before the nitrogen gas adsorption measurement. The micropore porosity (%) was calculated from the micropore pore volume (mL / g) and silica density (2.2 g / mL) determined by the t-plot method using the following formula.
Porosity (%) = 100 × pore volume / (1 / 2.2 + pore volume)

3. Preparation method of silica particle dispersion For ion-exchanged water, silica particles (colloidal silica, Na amount 45 ppb / solid, average primary particle size 35 nm, average secondary particle size 71.8 mm, association degree 2.1) and necessary 28 mass% ammonia water (Kishida Chemical Co., Ltd. reagent special grade) was added according to the above, and these were stirred and mixed for 30 minutes to obtain a mixed solution. Immediately thereafter, the mixed solution was converted into a 5 L molded liquid container Fujitainer (registered trademark). ) (Manufactured by Fujimori Kogyo Co., Ltd.) so that air does not enter, and the mixed solution is stored under the storage conditions (temperature and period of the mixed solution) described in Table 1, and Examples 1-26 and Comparative Example 1 A silica particle dispersion for ˜6 was obtained. The silica particle content in the mixed solution was adjusted to 10% by mass, and the ammonia content was adjusted so that the value of pH (25 ° C.) of the silica particle dispersion was as shown in Table 1. In addition, the description “period” in Table 1 is the “storage time”, and was counted from the point of time when sufficient stirring (for example, stirring for 30 minutes) was completed until the concentration of the constituent components of the silica particle dispersion became uniform. .

  The obtained silica particle dispersion was measured using a spectrophotometer UV-2550 manufactured by Shimadzu Corporation with a disposable cell (made of polystyrene) having an optical path length of 10 mm as an assumed container and a wavelength of 600 nm. The results are shown in Table 1.

4). Preparation method of aqueous additive solution The water-soluble polymer compounds shown in Table 1 were added to ion-exchanged water to obtain aqueous additive solutions for Examples 1 to 26 and Comparative Examples 1 to 6. The content of the water-soluble polymer compound in the additive aqueous solution was 2% by mass.

5). Preparation method of polishing liquid composition The silica particle dispersion and the aqueous additive solution are mixed so that the content of silica particles is 0.17% by mass and the content of water-soluble polymer compound is 0.02% by mass. Further, an aqueous medium was mixed to obtain Examples 1 to 26 and Comparative Examples 1 to 6 polishing liquid compositions.

6). Polishing Method After preparing a polishing composition obtained by mixing the silica particle dispersion and the aqueous additive solution as described above, it was immediately used for finish polishing under the following polishing conditions ([finish polishing conditions]). The object to be polished is a silicon wafer (silicon single-sided mirror wafer having a diameter of 200 mm, conductivity type: P, crystal orientation: 100, resistivity of 0.1 Ω · cm to less than 100 Ω · cm). Prior to the final polishing, rough polishing was performed on the silicon wafer in advance using a commercially available abrasive composition. The surface roughness (haze) of the silicon wafer after the rough polishing was 2.680 ppb. This surface roughness (haze) is a value in a dark field wide oblique incidence channel (DWO) measured using Surfscan SP1-DLS (trade name) manufactured by KLA Tencor.

[Finishing polishing conditions]
Polishing machine: Single-sided 8-inch polishing machine GRIND-X SPP600s (manufactured by Okamoto)
Polishing pad: Suede pad (Toray Cortex, Asker hardness 64, thickness 1.37mm, nap length 450um, opening diameter 60um)
Wafer polishing pressure: 100 gf / cm ²
Surface plate rotation speed: 60 rpm
Polishing time: 10 minutes Abrasive composition supply rate: 200 ml / min per silicon wafer
Abrasive composition temperature: 20 ° C
Carrier rotation speed: 60rpm

7). Cleaning method After final polishing, the silicon wafer was subjected to ozone cleaning and dilute hydrofluoric acid cleaning as follows. In ozone cleaning, pure water containing 20 ppm ozone was sprayed from a nozzle toward the center of a silicon wafer rotating at 600 rpm at a flow rate of 1 L / min for 3 minutes. At this time, the temperature of the ozone water was normal temperature. Next, dilute hydrofluoric acid cleaning was performed. In dilute hydrofluoric acid cleaning, pure water containing 0.5% ammonium hydrogen fluoride (special grade: Nacalai Tex Co., Ltd.) was sprayed from the nozzle toward the center of the silicon wafer rotating at 600 rpm at a flow rate of 1 L / min for 6 seconds. The above ozone cleaning and dilute hydrofluoric acid cleaning were performed as a set, for a total of 2 sets, and finally spin drying was performed. In the spin drying, the silicon wafer was rotated at 1500 rpm.

8). Various evaluations (1) Evaluation of surface defects (LPD) and surface roughness (haze) on the surface of a silicon wafer The surface roughness (haze) of a silicon wafer surface after cleaning is measured by a surface roughness measuring device “SurfscanSP1” (KLA Tencor) Dark field wide oblique incidence channel (DWO) values measured using Further, the surface defect (LPD) was measured at the same time as the Haze measurement, and evaluated by measuring the number of particles having a particle diameter of 50 nm or more on the silicon wafer surface. It shows that there are few surface defects, so that the numerical value of a surface defect (LPD) is small. In addition, the liquid mixture containing each of the polishing liquid compositions of Examples 1 to 26 and Comparative Examples 2 to 6 and the same composition containing silica particles, a basic compound, a water-soluble polymer compound, and an aqueous medium, respectively. The values of surface defects (LPD) and Haze (DWO) when a one-pack type polishing composition obtained by storing (ripening) for two weeks at the same storage temperature as in Examples and Comparative Examples is used for polishing. Each of these values is 1.0 (reference value), and surface defects (LPD) and Haze when the polishing liquid compositions of Examples 1 to 26 and Comparative Examples 2 to 6 are used for polishing according to the following evaluation criteria. (DWO) was evaluated. In addition, about the polishing liquid composition of the comparative example 1, since the aggregation of the silica particle was severe, evaluation of the surface defect (LPD) and surface roughness (haze) was not able to be performed.

<Evaluation criteria>
AA: The measured value is + 10% or less with respect to the reference value 1.0 A: The measured value is over + 10% and + 20% or less with respect to the reference value 1.0 B: The measured value is with respect to the reference value 1.0 + 20% to + 200% or less C: The measured value exceeds + 200% with respect to the reference value 1.0

(2) Wettability The area of the hydrophilized part (wet part) of the mirror surface of the silicon wafer (diameter 200 mm) immediately after the final polishing was visually observed. The measurement was performed on two different silicon wafers, the average value was evaluated according to the following evaluation criteria, and the results are shown in Table 1. In addition, about the polishing liquid composition of the comparative example 1, since the aggregation of the silica particle was severe, the wettability was not able to be evaluated.
(Evaluation criteria)
A: Ratio of wet part area is 95 or more B: Ratio of wet part area is 90% or more and less than 95% C: Ratio of wet part area is 50% or more and less than 90% D: Ratio of wet part area is less than 50%

  As shown in Table 1, the transmittance of light having a wavelength of 600 nm is 5.0% to 30% when the pH at 25 ° C. is 9 to 11 and the content of silica particles is 10% by mass. When the polishing liquid composition of the example using the silica particle dispersion is used, the surface defect (LPD) and the surface roughness (haze) of the polished silicon wafer are larger than when the polishing liquid composition of the comparative example is used. Is small. Further, a silica particle dispersion obtained by mixing a silica particle, a basic compound, and an aqueous medium and having a pH of 9 or more and 11 or less at 25 ° C. maintained at 10 to 80 ° C. for 1 day or more. When the polishing liquid composition of the example obtained by mixing the aqueous solution of the additive and the additive solution is used, the surface defect (LPD) and surface roughness of the polished silicon wafer are more than when the polishing liquid composition of the comparative example is used. The haze is small. Moreover, when using the polishing liquid composition of the example obtained by mixing the silica particle dispersion having a BET specific surface area ratio of 1.3 or more and 10 or less and the aqueous additive solution, the polishing liquid composition of the comparative example is used. The surface defect (LPD) and surface roughness (haze) of the polished silicon wafer are smaller than the case.

  The present invention can stably reduce the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface, and is useful in mass production of semiconductor substrates.

Claims (25)

A polishing composition for a silicon wafer obtained by mixing a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium,
A silicon wafer having a transmittance of light having a wavelength of 600 nm of the silica particle dispersion liquid of 5.0% or more and 30% or less when the content of the silica particles is 5% by mass or more and 20% by mass or less. Polishing liquid composition. A polishing composition for a silicon wafer obtained by mixing a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium,
The silica particle dispersion has a light transmittance at a wavelength of 600 nm, and the silica particle dispersion has a pH of 9 to 11 at 25 ° C., and the silica particle content is 10 to 15% by mass. In some cases, the polishing composition for a silicon wafer is from 5.0% to 30%. A polishing composition for a silicon wafer obtained by mixing a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium,
The silica particle dispersion has a light transmittance at a wavelength of 600 nm of 5.0% to 30%, the silica particle dispersion has a pH at 25 ° C. of 9 to 11, and the silica particle content is 10 A polishing composition for silicon wafers, comprising at least 15% by mass and no more than 15% by mass. A polishing composition for a silicon wafer obtained by mixing a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium,
BET ratio obtained by dividing the BET specific surface area of freeze-dried silica particles obtained by freeze-drying the silica particle dispersion by the BET specific surface area of air-dried silica particles obtained by air-drying the silica particle dispersion. A polishing composition for a silicon wafer, wherein the surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) is 1.3 or more and 10 or less.   The polishing composition for a silicon wafer according to claim 4, wherein the amount of silanol groups per unit mass of the silica particles after freeze-drying is 2.1 mmol / g or more and 10 mmol / g or less.   The polishing composition for a silicon wafer according to claim 4 or 5, wherein a porosity of the silica particle surface after the freeze-drying is 1.5% or more and 30% or less.   The water-soluble polymer compound is polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, polyethylene glycol, polyoxyethylene, N-hydroxyethylacrylamide (HEAA) homopolymer, and N-isopropylacrylamide (NIPAM) and acrylamide (AAm). The polishing liquid composition for silicon wafers according to any one of claims 1 to 6, comprising at least one water-soluble polymer compound selected from the group consisting of copolymers of   Furthermore, the polishing liquid composition for silicon wafers in any one of Claim 1 to 7 in which the said additive aqueous solution contains a polyoxyalkylene compound. A silica particle dispersion (first liquid) containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution (second liquid) containing a water-soluble polymer compound and an aqueous medium,
In the case where the light transmittance at a wavelength of 600 nm of the silica particle dispersion (first liquid) is any one of 5% by mass to 20% by mass, the silica particle content is 5.0% to 30%. A polishing composition composition kit for silicon wafers. A silica particle dispersion (first liquid) containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution (second liquid) containing a water-soluble polymer compound and an aqueous medium,
The silica particle dispersion (first liquid) has a light transmittance of a wavelength of 600 nm, the silica particle dispersion has a pH of 9 to 11 at 25 ° C., and the silica particle content is 10 to 15% by mass. In any of the following cases, the polishing composition composition kit for a silicon wafer is 5.0% to 30%. A silica particle dispersion (first liquid) containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution (second liquid) containing a water-soluble polymer compound and an aqueous medium,
The BET specific surface area of the silica particles after freeze-drying obtained by freeze-drying the silica particles in the silica particle dispersion, and the air-dried silica particles obtained by air-drying the silica particles in the silica particle dispersion BET specific surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) obtained by dividing by the BET specific surface area of the polishing composition for silicon wafers is 1.3 to 10 kit.   The polishing composition composition for a silicon wafer according to claim 11, wherein the amount of silanol groups per unit mass of the silica particles after lyophilization is 2.1 mmol / g or more and 10 mmol / g or less.   The polishing composition kit for a silicon wafer according to claim 11 or 12, wherein a porosity of the surface of the silica particles after lyophilization is 1.5% or more and 30% or less.   The water-soluble polymer compound is polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, polyethylene glycol, polyoxyethylene, N-hydroxyethylacrylamide (HEAA) homopolymer, and N-isopropylacrylamide (NIPAM) and acrylamide (AAm). 14. The polishing composition composition for a silicon wafer according to claim 9, comprising at least one water-soluble polymer compound selected from the group consisting of a copolymer with   Furthermore, the polishing composition composition kit for silicon wafers according to any one of claims 9 to 14, wherein the additive aqueous solution contains a polyoxyalkylene compound. A method for producing a polishing composition for a silicon wafer comprising silica particles, a basic compound, a water-soluble polymer compound, and an aqueous medium,
A step of mixing a water-soluble polymer compound and an aqueous medium to obtain an aqueous additive solution;
A step of obtaining a silica particle dispersion by holding a mixed solution having a pH of 9 or more and 11 or less at 25 ° C. obtained by mixing silica particles, a basic compound and an aqueous medium at 10 to 80 ° C. for 1 day or more. When,
A method for producing a polishing composition for a silicon wafer, comprising a step of mixing the silica particle dispersion and the aqueous additive solution. A method for producing a polishing composition composition kit for a silicon wafer according to any one of claims 9 to 15,
A step of mixing a water-soluble polymer compound and an aqueous medium to obtain an aqueous additive solution;
A step of obtaining a silica particle dispersion by holding a mixed solution having a pH of 9 or more and 11 or less at 25 ° C. obtained by mixing silica particles, a basic compound and an aqueous medium at 10 to 80 ° C. for 1 day or more. And a method for producing a polishing composition composition kit for silicon wafers. A silica particle dispersion containing silica particles, a basic compound, and an aqueous medium,
The silica particle dispersion has a light transmittance at a wavelength of 600 nm, and the silica particle dispersion has a pH of 9 to 11 at 25 ° C., and the silica particle content is 10 to 15% by mass. In some cases, the silica particle dispersion is 5.0% to 30%. A silica particle dispersion containing silica particles, a basic compound, and an aqueous medium,
BET ratio obtained by dividing the BET specific surface area of freeze-dried silica particles obtained by freeze-drying the silica particle dispersion by the BET specific surface area of air-dried silica particles obtained by air-drying the silica particle dispersion. A silica particle dispersion having a surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) of 1.3 or more and 10 or less. A silica particle dispersion containing silica particles, a basic compound, and an aqueous medium,
BET ratio obtained by dividing the BET specific surface area of freeze-dried silica particles obtained by freeze-drying the silica particle dispersion by the BET specific surface area of air-dried silica particles obtained by air-drying the silica particle dispersion. A silica particle dispersion having a surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) of 1.3 or more and 10 or less.   A method for producing a polishing composition for a silicon wafer, comprising a step of mixing the silica particle dispersion according to any one of claims 18 to 20, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium.   The manufacturing method of a semiconductor substrate including the process of grind | polishing a to-be-polished silicon wafer using the polishing liquid composition for silicon wafers in any one of Claim 1 to 8.   A method for polishing a silicon wafer to be polished, comprising a step of polishing the silicon wafer to be polished using the polishing composition for a silicon wafer according to any one of claims 1 to 8.   The manufacturing method of a semiconductor substrate including the process of grind | polishing a to-be-polished silicon wafer using the polishing liquid composition kit for silicon wafers in any one of Claims 9-15.   A method for polishing a silicon wafer to be polished, comprising a step of polishing the silicon wafer to be polished using the polishing composition composition for a silicon wafer according to any one of claims 9 to 15.