JP2020098924A - Composition for silicon wafer polishing liquid or composition kit for silicon wafer polishing liquid - Google Patents

Abstract

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

2. Description of the Related Art In recent years, the design rule of semiconductor devices has become finer due to the increasing demand for higher recording capacities 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 reducing surface defects (LPD: Light point defects) and surface roughness (haze) of silicon wafers (bare wafers). It is getting tougher.

In order to improve the quality of silicon wafers, polishing of silicon wafers is performed in multiple stages. Particularly, final polishing performed in 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 composition for use in polishing silicon wafers, the purpose is to improve storage stability, ensure a polishing rate that ensures good productivity, and reduce surface defects (LPD) and surface roughness (haze). , A silica wafer, a nitrogen-containing basic compound, and a water-soluble polymer compound containing a constitutional unit derived from an acrylamide derivative such as hydroxyethyl acrylamide (HEAA) are 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). Further, 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 the compound has been disclosed (Patent Document 3).

These polishing liquid compositions are stored and transported in a concentrated state within a range where their storage stability is not impaired, and used for polishing silicon wafers, from the viewpoint of economical efficiency such as reduction in manufacturing and transportation costs. It is often used by a user after diluting it with ion-exchanged water or the like as needed. Further, the polishing liquid composition is such that an abrasive grain dispersion containing abrasive grains, a basic compound and water and an aqueous solution of an aqueous solution polymer are separately stored, these are mixed at the time of use, and diluted with water as necessary. It may be a two-component type (Patent Document 4).

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

However, when the concentrated polishing liquid composition is used for polishing a silicon wafer after dilution, or after the respective liquids constituting the two-component polishing liquid composition are mixed, the obtained polishing liquid composition is treated with silicon. When used for polishing a wafer, sometimes the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface were not sufficiently reduced.

In the present invention, a polishing liquid composition for a silicon wafer capable of stably reducing surface roughness (haze) and surface defects (LPD) of a polished silicon wafer surface, a method for producing the same, and a polishing liquid composition for the silicon wafer Provided are a method for polishing a silicon wafer to be polished and a method for manufacturing a semiconductor substrate, using the object. Further, in the present invention, a polishing liquid composition kit for a silicon wafer capable of stably reducing surface roughness (haze) and surface defects (LPD) of a polished silicon wafer surface, a method for producing the same, and the silicon wafer Provided are a method for polishing a silicon wafer to be polished and a method for manufacturing a semiconductor substrate, which uses a polishing composition composition kit. Further, the present invention provides a silica particle dispersion liquid used for preparation of a polishing liquid composition for a silicon wafer, which can stably reduce surface roughness (haze) and surface defects (LPD) of a polished silicon wafer surface. To do.

One embodiment of the polishing composition for a silicon wafer of the present invention is a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an additive aqueous solution containing a water-soluble polymer compound and an aqueous medium. The polishing composition for silicon wafers obtained by the above, wherein the silica particle dispersion has 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. It was obtained by holding the mixed solution of 10° C. or higher and 80° C. or lower for 1 day or longer.

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

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

Another embodiment of the polishing liquid composition for a silicon wafer of the present invention is a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an additive aqueous solution containing a water-soluble polymer compound and an aqueous medium. A polishing liquid composition for a silicon wafer obtained by mixing, wherein the BET specific surface area of freeze-dried silica particles obtained by freeze-drying the silica particle dispersion was 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 BET specific surface area of air-dried silica particles is 1.3 or more and 10 or less.

One embodiment of the polishing composition composition kit for a silicon wafer of the present invention contains a silica particle dispersion liquid (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 an additive (second liquid) is included, and the silica particle dispersion liquid (first liquid) has a pH of 9 or more at 25° C. obtained by mixing the silica particles, the basic compound, and the aqueous medium. It was obtained by holding a mixed solution of 11 or less at 10° C. or higher and 80° C. or lower for 1 day or longer.

Another aspect of the polishing liquid composition kit for a silicon wafer of the present invention is a silica particle dispersion liquid (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 silica particle dispersion liquid (first liquid) having a transmittance of light having a wavelength of 600 nm in which the content of the silica particles is 5% by mass or more and 20% by mass or less. In that case, it is 5.0% or more and 30% or less.

Another aspect of the polishing liquid composition kit for a silicon wafer of the present invention is a silica particle dispersion liquid (first liquid) containing silica particles, a basic compound and an aqueous medium, a water-soluble polymer compound and an aqueous medium. And an additive aqueous solution (second liquid) containing, wherein the silica particle dispersion liquid (first liquid) has a transmittance of light having a wavelength of 600 nm at a pH of 25 to 25° C. of the silica particle dispersion liquid of 9 or more and 11 or less. When the content of the 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 liquid composition kit for a silicon wafer of the present invention is a silica particle dispersion liquid (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 above, and 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 BET specific surface area of 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 maintaining 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 to obtain a silica particle dispersion, the silica particle dispersion and the additive Mixing with an aqueous solution.

One aspect of a method for producing a polishing composition composition kit for a silicon wafer of the present invention is 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. Holding a mixed solution having a pH of 9 or more and 11 or less at 25° C. at 25° C. at 10° C. or more and 80° C. or less for 1 day or more to obtain a silica particle dispersion.

One embodiment 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 transmittance of light having a wavelength of 600 nm of the silica particles. When the pH of the dispersion liquid at 25° C. is 9 or more and 11 or less and the content of the silica particles is 10% by mass or more and 15% by mass or less, it is 5.0% or more and 30% or less.

Another embodiment 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 is freeze-dried to obtain freeze-dried silica particles. The BET specific surface area 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 embodiment 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 is freeze-dried to obtain freeze-dried silica particles. The BET specific surface area 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 (B of the freeze-dried silica particles
(ET specific surface area/BET specific surface area of air-dried silica 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 is a silica particle dispersion containing silica particles, a basic compound, and an aqueous medium, and an additive aqueous solution containing a water-soluble polymer compound and an aqueous medium. And a step of mixing with.

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

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

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

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

ADVANTAGE OF THE INVENTION According to this invention, 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, its manufacturing method, and the said silicon wafer. 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 for polishing.

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

Further, according to the present invention, a silica particle dispersion used for preparing a polishing composition for a silicon wafer, which can stably reduce surface roughness (haze) and surface defect (LPD) of a polished silicon wafer surface. A liquid can be provided.

A method of polishing a silicon wafer to be polished using a silicon wafer polishing liquid composition containing silica particles, a basic compound, and a water-soluble polymer compound (hereinafter, may be simply referred to as “polishing liquid composition”). 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, and suppresses the silica particles directly causing the deterioration of the surface roughness (haze) from directly contacting the silicon wafer to be polished, and It acts to suppress the 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 improvement of polishing rate, improvement of desorption of particles (silica particles and polishing debris) in the cleaning step of a polished silicon wafer, and reduction of surface roughness (haze). There is. Further, the improvement of the detachability of particles contributes to the reduction of surface defects (LPD).

However, the surface roughness (haze) and the surface defect (LPD) sometimes fluctuated even when the polishing composition having the same composition was used. The present inventors, as a result of exploring the cause of this variation, the cause is that excessive adsorption of the water-soluble polymer compound to the silica particles causes the above-mentioned action of the water-soluble polymer compound on the wafer, specifically, water-soluble polymer compound. It is thought that this is because the inhibition of the corrosion of the wafer surface and the improvement of the desorption property of particles by the hydrophilic polymer compound are hindered. Then, the mixed solution obtained by mixing the silica particles, the basic compound and the aqueous medium is aged for a predetermined time at a predetermined temperature, and the silica particle dispersion obtained by using it for the preparation of the polishing composition is specifically used. Is a mixture of silica particles, a basic compound and an aqueous medium and having a pH of 9 or more and 11 or less at 25° C. at a temperature of 10° C. or more and 80° C. or less for 1 day or more, whereby water on the surface of the silica particles is After sufficiently stabilizing the Japanese layer, by mixing the silica particles and the water-soluble polymer compound, excessive adsorption of the water-soluble polymer compound on the silica particles is suppressed, It has been found that the above-mentioned action on the wafer is sufficiently exhibited. However, these are estimations, and the present invention is not limited to these mechanisms.

After sufficiently stabilizing the hydrated layer on the surface of the silica particles, the polishing liquid composition obtained by mixing the silica particle dispersion and the additive aqueous solution is immediately used for polishing the silicon wafer to be polished. Also, the surface roughness (haze) and the surface defect (LPD) can be stably reduced.

Further, after the silica particle dispersion is prepared, if the silica particle dispersion is stored (aged) for a predetermined time under a predetermined condition, the light transmittance becomes lower than that immediately after the preparation of the silica particle dispersion. From this, the present inventors have found that there is a correlation between the above-mentioned transmittance of the silica particle dispersion and the stability of the hydrated layer of silica particles. Specifically, when the content of silica particles in the silica particle dispersion is 5% by mass or more and 20% by mass or less, the transmittance of the silica particle dispersion for light having a wavelength of 600 nm is 5.0%. Or more and 30% or less, or the pH of the silica particle dispersion at 25° C. is 9 or more and 11 or less and the content of the silica particles is 10% by mass or more and 15% by mass or less, either. Of light with wavelength of 600 nm is 5.0% or more 3
When it is 0% or less, it is assumed that the hydrated layer of silica particles is sufficiently stabilized. If a polishing liquid composition prepared using a silica particle dispersion liquid having such optical characteristics 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 can be stably reduced (hereinafter referred to as “stability of the present invention”). In some cases, it has been referred to as a "chemical effect".

Further, it is observed that when the aging period of the silica particle dispersion liquid is prolonged, the surface roughness (haze) and surface defects (LPD) of the silicon wafer surface, particularly the surface defects (LPD) are reduced. Further, when the aging period is prolonged, it is observed that the BET specific surface area of freeze-dried silica particles obtained by freeze-drying the silica particle dispersion (hereinafter also referred to as “freeze-dried silica particles”) increases. .. However, there is no correlation between the BET specific surface area of the air-dried silica particles (hereinafter also referred to as “air-dried silica particles”) obtained by air-drying the silica particle dispersion and the aging time. .. From these facts, during the aging period, the Si-O bond on the surface of the silica particles in the silica particle dispersion liquid is hydrolyzed with alkali to form reversible pores on the surface of the silica particles, which results in freeze-drying. It is presumed that the BET specific surface area of the silica particles is increasing. A BET specific surface area ratio (BET specific surface area of freeze-dried silica particles, which is obtained by storing the freeze-dried silica particles for a predetermined period of time and is a 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 /BET specific surface area of air-dried silica particles is 1.3 or more and 10 or less. When a polishing composition prepared using a silica particle dispersion is used, the presence of the pores causes the silica of the water-soluble polymer compound to be present. Excessive adsorption on the particles is suppressed, or the ground area of the silica particles on the silicon wafer is reduced, and in the cleaning step of the polished silicon wafer, the removability of the silica particles adsorbed on the silicon wafer is improved. It is presumed that the surface roughness (haze) and surface defects (LPD) can be stably reduced.

In one embodiment, the present invention is a one-component type polishing comprising a silica particle dispersion liquid containing silica particles, a basic compound and an aqueous medium, and an additive aqueous solution containing a water-soluble polymer compound and an aqueous medium. It is a liquid composition. The one-component polishing liquid composition of the present invention is a silica particle dispersion liquid, which is obtained by mixing silica particles, a basic compound, and an aqueous medium. Obtained by holding at 80°C or lower for 1 day or longer, and when the content of silica particles is 5% by mass or more and 20% by mass or less, the transmittance of light having a wavelength of 600 nm is 5.0% or more. 30% or less, the silica particle dispersion has a pH of 9 at 25°C.
When the content of the silica particles is 11 or more and the content of the silica particles is 10 mass% or more and 15 mass% or less, the transmittance of light having a wavelength of 600 nm of the silica particle dispersion is 5.0% or more and 30% or less. , Or a 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. It was possible to overcome the problem that the polishing performance was unstable when the polishing liquid composition was used for polishing immediately after the preparation of the polishing liquid composition. Even if there is, the surface roughness (haze) and surface defect (LPD) of the polished silicon wafer surface can be reduced.

In addition, the present invention, in another aspect, a silica particle dispersion liquid (first liquid) containing silica particles, a basic compound, and an aqueous medium, and an additive aqueous solution containing a water-soluble polymer compound and an aqueous medium (the first liquid). Two liquids) are stored in a state of not being mixed with each other, and these are a polishing liquid composition kit for silicon wafers (two-liquid type polishing liquid composition) to be blended at the time of use. The silica particle dispersion liquid (first liquid) has a transmittance of light having a wavelength of 600 nm 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. A silica particle dispersion having a pH of 9 or more and 11 or less and a silica particle content of 10% by mass or more and 15% by mass or less at a wavelength of 600 nm of a silica particle dispersion. A light transmittance of 5.0% or more and 30% or less, or a 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 liquid holds, for example, 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° C. or more and 80° C. or less for one day or more. It can be obtained.

In addition, in the present invention, "when the transmittance of light having a wavelength of 600 nm of the silica particle dispersion is 5% by mass or more and 20% by mass or less, 5.0% or more and 30% or more %" or less", which means that the silica particle dispersion liquid used in the preparation of the one-component polishing liquid composition of the present invention, and the polishing liquid composition kit for a silicon wafer of the present invention (hereinafter It may be abbreviated as "polishing liquid composition preparation kit".) The content of silica particles in the silica particle dispersion liquid (first liquid) constituting the kit is always 5% by mass or more and 20% by mass or less. It is not stipulated, for example, the content ratio of the silica particles and the basic compound in the silica particle dispersion liquid having a silica particle content of 5% by mass or more and 20% by mass or less, and the content thereof. The silica particle dispersion liquid having the same quantitative ratio is also included in the silica particle dispersion liquid. That is, when the content of the silica particles is not within the above range, the content of the silica particles is adjusted to 5% by mass or more and 20% by mass or less by changing the amount of the aqueous medium to obtain the transmittance. You can

Further, in the present invention, “the transmittance of the silica particle dispersion liquid for light having a wavelength of 600 nm is 9 or more and 11 or less when the pH of the silica particle dispersion liquid at 25° C. is 10 or more and 15% or less by mass. In either case of mass% or less, it is 5.0% or more and 30% or less."
The silica particle dispersion liquid used in the preparation of the one-component polishing liquid composition of the present invention, and the silica particle dispersion liquid constituting the polishing liquid composition preparation kit of the present invention ( It does not stipulate that the content of silica particles in the first liquid) is 10% by mass or more and 15% by mass or less. For example, the transmittance of light having a wavelength of 600 nm is 5.0% or more and 30% or less. In the silica particle dispersion liquid, the pH at 25° C. is 9 or more and 11 or less, preferably 10±0.3, and the content of silica particles is 10% by mass or more and 15% by mass or less, preferably 10% by mass. The silica particle dispersion liquid also includes a silica particle dispersion liquid in which the content ratios of the silica particles and the basic compound are the same. That is, it is possible to easily determine the transmittance by clarifying the pH of the silica particle dispersion liquid and the content of the silica particles.

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

The polishing liquid 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 liquid (first liquid). A product obtained by holding a mixed solution of 9 or more and 11 or less at 10° C. or more and 80° C. or less for 1 day or more, and a wavelength of 600 nm when the content of silica particles is 5% by mass or more and 20% by mass or less. Having a light transmittance of 5.0% or more and 30% or less, a pH of the silica particle dispersion at 25° C. of 9 or more and 11 or less, and a silica particle content of 10% by mass or more and 15% by mass or less And the silica particle dispersion has a transmittance of light having a wavelength of 600 nm of 5.0.
% Or more and 30% or less, or a 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. The polishing liquid of the present invention can overcome the problem of the liquid type polishing liquid composition, that is, the polishing performance is unstable when the polishing liquid composition obtained by mixing two liquids is immediately used for polishing. Even when the polishing liquid composition obtained by mixing the two liquids constituting the composition preparation kit is immediately used for polishing, the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer are reduced. You can do it.

Further, in the polishing liquid composition preparation kit of the present invention, the silica particle dispersion liquid (first liquid) and the additive aqueous solution (second liquid) are stored separately from each other. (1 liquid) and the additive aqueous solution (second liquid) are mixed, the silica particle dispersion liquid (first liquid) and the additive aqueous solution (second liquid) are adjusted by adjusting the amount of the additive aqueous solution (second liquid) used. It is possible to adjust the concentration of the water-soluble polymer compound or the like in the polishing liquid composition obtained by mixing the liquid with the liquid), and to prepare various polishing liquid compositions.

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

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

The silica particles (component A) are preferably used in a slurry form 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 with an alkali metal, an alkaline earth metal or the like. The silica particles obtained from the hydrolyzate of alkoxysilane can be produced by a conventionally known method. The preferred pH range of 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 stabilizing effect of the present invention, but from the viewpoint of ensuring the polishing rate, preferably 5 nm or more, more preferably 10 nm or more, further preferably 15 nm. The above is still more preferably 20 nm or more. Further, from the viewpoint of securing a polishing rate and reducing surface defects (LPD) at the same time, it is preferably 50 nm or less, more preferably 45 nm or less, still 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 the specific surface area S (m ² /g) calculated by the BET (nitrogen adsorption) method. The specific surface area can be measured, for example, by the method described in Examples.

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, from the viewpoint of securing a polishing rate and reducing surface defects of the silicon wafer, and preferably It is 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 so-called spherical type and 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 further preferably 2.3 or less, from the viewpoint of securing a polishing rate and reducing surface defects. It is preferably 1.1 or more, more preferably 1.5 or more, still more preferably 1.8 or more.

The degree of association 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 by using the device described in Examples, for example.
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, but, for example, JP 6-254383 A, JP 11-214338 A, JP 11-60232 A, JP 2005-060217 A, The method described in Japanese Patent Laid-Open No. 2005-060219 can be adopted.

From the viewpoint of reducing surface defects (LPD) of the silicon wafer, Na contained in the silica particles (component A) used for preparing the silica particle dispersion is preferably 100 ppb mass% or less, more preferably 50 ppb mass% or less, It is preferably 30 ppb mass% or less. The concentration of impurities such as Na contained in the silica particles (component A) can be measured by a method such as plasma emission analysis (ICP) or 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 further preferably from the viewpoint of economy such as reduction in manufacturing and transportation costs. 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, and preferably 400 m ² /g or less, more preferably 300 from the viewpoint of improving the polishing rate.
m ² /g or less, more preferably 250 m ² /g or less. The BET specific surface area of the freeze-dried silica particles can be measured by the method described in Examples below.

The BET specific surface area ratio, which is a 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 standpoint of enabling reduction, it is 1.3 or more, preferably 1.5 or more, more preferably 2.0 or more, and 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 liquid with an air flow, and can be measured by the method described in Examples below.

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

The porosity of the freeze-dried silica particles is preferably 1.5% or more, more preferably from the viewpoint that the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface can be stably reduced. 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. The porosity of the freeze-dried silica particles can be measured by the method described in Examples below.

[Basic compound (component B)]
The silica particle dispersion contains a water-soluble basic compound (component B) from the viewpoints of improving storage stability, ensuring a polishing rate, and reducing surface defects (LPD) and surface roughness of a 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° C.) means that it has a solubility of 0.5 g/100 ml or more, preferably 2 g/100 ml or more, and the “water-soluble basic compound” means when it is dissolved in water. , Refers to a compound that exhibits basicity.

Examples of at least one or more nitrogen-containing basic compounds selected from amine compounds and ammonium compounds include ammonia, ammonium hydroxide, ammonium carbonate, ammonium hydrogencarbonate, 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, hexamethylenediamine, piperazine hexahydrate, anhydrous piperazine, 1-(2-aminoethyl) Examples include piperazine, N-methylpiperazine, diethylenetriamine, and tetramethylammonium hydroxide. You may use these nitrogen-containing basic compounds in mixture of 2 or more types. As the nitrogen-containing basic compound contained in the silica particle dispersion liquid, the surface roughness (haze) and surface defects (LPD) of the silicon wafer are reduced, the storage stability of the silica particle dispersion liquid is improved, and the polishing speed is secured. From the viewpoint of, 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, from the viewpoint of improving the dispersibility of the silica particles.
More preferably, it is 0.5 mass% or more. In addition, 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 (silica particles/basic compound) of the silica particles (component A) and the basic compound (component B) contained in the silica particle dispersion is preferably 0.6 or more from the viewpoint of improving storage stability, It is more preferably 1 or more, still more preferably 3 or more. Further, from the viewpoint of improving the dispersibility of silica particles, it is preferably 500 or less, more preferably 200 or less, still more preferably 100 or less.

[Aqueous medium]
Examples of the aqueous medium contained in the silica particle dispersion include water such as ion-exchanged water or ultrapure water, or a mixed medium of water and a solvent, and the solvent includes a solvent miscible with water (for example, Alcohol such as ethanol) is preferred. From the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer, ion-exchanged water or ultrapure water is more preferable as the aqueous medium, and ultrapure water is even more preferable. When 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 unless the effect of the present invention is hindered, but from the viewpoint of economy, 95 mass% or more is preferable, 98 mass% or more is more preferable, and substantially 100 mass% is still more preferable.

The transmittance of light having a wavelength of 600 nm of the silica particle dispersion is such that when the content of the 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), preferably 5.0% or more, more preferably 5% or more, further preferably 8.0% or more, still more preferably 8% or more, still more preferably 11% or more. It is preferably 30% or less, more preferably 24% or less, still more preferably 16% or less.

From the viewpoint of avoiding uncertainties, the silica particle content is 10 mass, and the silica particle dispersion liquid has a measurement temperature of 25° C. of 25° C. from the viewpoint of avoiding uncertainties. PH is 9 or more and 11 or less. 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 that constitutes the polishing composition of the present invention is not particularly limited as long as it is dissolved in the concentration range for polishing of the present invention. The term “water-soluble” of the water-soluble polymer compound means that it has a solubility of 0.5 g/100 ml or more in water (20° C.), and preferably has a solubility of 2 g/100 ml or more. The polyoxyalkylene compound (component D) described later is a water-soluble polymer compound, but is excluded from the category of component C.

From the viewpoint of securing a polishing rate and reducing surface defects (LPD) and surface roughness (haze) of a silicon wafer, examples of the monomer that is a supply source that constitutes the water-soluble polymer compound (component C) include: 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 aqueous additive solution include a water-soluble polymer compound containing a constitutional unit derived from a polyamide, a cellulose derivative, a polyvinyl alcohol polymer, and an acrylamide derivative. Examples of the polyamide include polyvinylpyrrolidone, polyacrylamide, polyoxazoline, polydimethylacrylamide, polydiethylacrylamide, polyisopropylacrylamide, polyhydroxyethylacrylamide and the like. Examples of the cellulose derivative 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 polyvinyl alcohol-based polymers include polyvinyl alcohol (PVA), alkylene oxide-modified PVA, cation-modified PVA, anion-modified PVA, alkyl-modified PVA and the like. Examples of the water-soluble polymer compound containing a structural unit derived from an acrylamide derivative include a water-soluble polymer compound containing 75 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 as the source of the structural unit I represented by the general formula (1) is an acrylamide derivative such as N-hydroxyethyl acrylamide (HEAA) or N-hydroxymethyl acrylamide (HMAA). They may be used alone 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.

Regarding a water-soluble polymer compound containing a constitutional unit derived from an acrylamide derivative, "containing 75 mass% or more of the constitutional unit I" means that the mass of the constitutional 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. In addition, in the present specification, the content (% by mass) of the structural unit I in all the structural units constituting the water-soluble polymer compound is, depending on the synthesis conditions, the reaction in all steps of the synthesis of the water-soluble polymer compound. 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. ..

From the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer, the ratio of the structural unit I in all the structural units of the water-soluble polymer compound containing the structural unit derived from an acrylamide derivative is 75. It is at least mass%, preferably at least 80 mass%, more preferably at least 90 mass%, even more preferably substantially 100 mass%, and even more preferably 100 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 effects of the present invention are exhibited. When a constitutional unit other than the constitutional unit I (also referred to as “constitutional unit II”) is contained, the constitutional unit other than the constitutional unit I reduces 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). The structural unit II derived from is preferable, and N-isopropylacrylamide (NIPAM) is more preferable.

When 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 of the structural unit I and the structural unit II is The array may be block or random.

Specific examples of the water-soluble polymer compound include HEAA homopolymer, HMAA homopolymer, HEAA and HMAA copolymer, HEAA and NIPAM copolymer, HMAA and NIPAM copolymer, HEAA and HMAA and 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 Polymers, HMAA/MAA copolymers, HMAA/VP copolymers, HMAA/DMAA copolymers, HMAA/DEAA copolymers, etc. Polymers may be used, and these may be used alone or in combination of two or more, but from the viewpoint of reducing surface defects of the silicon wafer, HEAA homopolymer, HMAA homopolymer, and copolymer of HEAA and HMAA. , A copolymer of HEAA and NIPAM, a copolymer of HMAA and NIPAM, and a copolymer of HEAA, HMAA and NIPAM, preferably at least one polymer, HEAA homopolymer, HMAA homopolymer At least one polymer selected from the group consisting of a combination and a copolymer of HEAA and HMAA is more preferable, and a HEAA homopolymer is still more preferable.

Two or more kinds of these water-soluble polymer compounds may be mixed and used at an arbitrary ratio. Among these water-soluble polymer compounds, polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, polyethylene glycol, HEAA homopolymer, and, from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of silicon wafers, and At least one water-soluble polymer compound selected from the group consisting of copolymers of NIPAM and acrylamide (AAm) is preferable, and polyvinyl alcohol, hydroxyethyl cellulose, HEAA homopolymer, and group of NIPAM and AAm copolymer. At least one water-soluble polymer compound selected from the above is more preferable.

The weight average molecular weight of polyvinyl alcohol is preferably 10,000 or more, more preferably 15,000 or more, 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 the aggregation of silica particles, it is preferably 150,000 or less, more preferably 100,000 or less, still more preferably 80,000 or less. The weight average molecular weight of polyvinyl alcohol is measured by the method described in Examples below.

The weight average molecular weight of polyvinylpyrrolidone is preferably 10,000 or more, more preferably 30,000 or more, and further 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 the aggregation of silica particles, it is preferably 1,000,000 or less, more preferably 700,000 or less, and further preferably 600,000 or less. The weight average molecular weight of polyvinylpyrrolidone is measured by the method described in Examples below.

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 the aggregation of silica particles, it is preferably 1.5 million or less, more preferably 1.1 million or less, and further 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, and further preferably 200,000 or more from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. , Still more preferably 300,000 or more, still more preferably 40
From the viewpoint of suppressing the aggregation of silica particles, it is 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. is there. 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, further preferably from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. It is preferably 200,000 or more, more preferably 300,000 or more, and preferably 1,000,000 or less, more preferably 800,000 or less, and further preferably 600,000 or less from the viewpoint of suppressing aggregation of silica particles. The weight average molecular weight of the copolymer of NIPAM and AAm is measured by the method described in Examples below.

The content of the water-soluble polymer compound (component C) contained in the aqueous additive solution is preferably 0.5% by mass or more, more preferably 1% by mass, from the viewpoint of economy such as reduction in manufacturing and transportation costs. As described above, the content is more preferably 1.5% by mass or more, and from the viewpoint of improving storage stability, it is preferably 20% by mass or less, more preferably 15% by mass or less, still more preferably 12% by mass or less.

The conditions of the aqueous medium contained in the additive aqueous solution may be the same as those of the aqueous medium contained in the silica particle dispersion liquid.

Regarding the polishing liquid composition obtained by mixing the silica particle dispersion and the additive aqueous solution, the mass ratio of the silica particles (component A) and the 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, further preferably 0.009 or more, from the viewpoint of improving the dispersibility of silica particles and reducing the surface defects of the silicon wafer. Is more preferably 0.015 or more, preferably 1.0 or less, more preferably 0.8 or less, even more preferably 0.6 or less, even more preferably 0.4 or less, still more preferably 0.3 or less. Is.

The pH at 25° C. of a mixed liquid (polishing liquid composition) used for polishing a silicon wafer to be polished and obtained by mixing a silica particle dispersion liquid constituting a polishing liquid composition and an additive aqueous solution and a diluted liquid thereof at 25° C. 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 adjuster (for example, ammonia). Here, the pH at 25° C. can be measured using a pH meter (for example, Toa Denpa Kogyo HM-30G), and is a numerical value 1 minute after the electrode is immersed in the polishing composition.

[Polyoxyalkylene Compound (Component D)]
The additive aqueous solution may further contain a polyoxyalkylene compound. The polyoxyalkylene compound is adsorbed on the silicon wafer to be polished. Therefore, the polyoxyalkylene compound, while suppressing the corrosion of the wafer surface by the basic compound, by imparting wettability to the wafer surface, adhesion of particles to the wafer surface that is considered to be caused by the drying of the wafer surface Acts to suppress. Further, in the step of cleaning the polished silicon wafer, the polyoxyalkylene compound weakens the interaction between the silica particles and the silicon wafer. Therefore, it is considered that the polyoxyalkylene compound enhances the reduction of the surface roughness (haze) and the surface defect (LPD) together with the water-soluble polymer compound.

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

The number of hydroxyl groups of the polyhydric alcohol, which is the source (raw material) of the polyoxyalkylene compound (component D), depends on the surface defect (LPD) and surface roughness of the silicon wafer from the viewpoint of increasing the adsorption strength of the polyoxyalkylene compound on the silicon wafer surface. 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, 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, ethylene glycol alkylene oxide adducts are preferable.

The polyoxyalkylene compound (component D) contains at least one alkyleneoxy group selected from the group consisting of ethyleneoxy groups (EO) and propyleneoxy groups (PO), but has surface defects (LPD) and surface of silicon wafers. From the viewpoint of reduction of 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, more preferably from the viewpoint of increasing the adsorption amount of the polyoxyalkylene compound to the silicon wafer to be polished and reducing the surface roughness (haze). It is preferably 700 or more, more preferably 900 or more, and is preferably 250,000 or less, more preferably from the viewpoint of increasing the adsorption amount of the polyoxyalkylene compound to the silica particles and reducing the surface roughness (haze). It is 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 the peak in the chromatogram obtained by applying the gel permeation chromatography (GPC) method under the following conditions.
<Measurement condition>
Device: HLC-8320 GPC (Tosoh Corporation, detector integrated type)
Column: GMPWXL+GMPWXL (anion)
Eluent: 0.2M phosphate buffer/CH ₃ CN=9/1
Flow rate: 0.5 ml/min
Column temperature: 40℃
Detector: RI Detector Standard substance: Monodisperse polyethylene glycol with known molecular weight

In a polishing liquid composition obtained by mixing a silica particle dispersion and an additive aqueous solution, a mass ratio of polyoxyalkylene compound (component D) and 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, 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 (mass of water-soluble polymer compound/mass of polyoxyalkylene compound) of the water-soluble polymer compound (component C) and the polyoxyalkylene compound (component D) contained in the aqueous additive solution is the surface defect of the silicon wafer. From the viewpoint of reduction of (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. Or less, more preferably 60 or less, still more preferably 40 or less.

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

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

<Alcohol>
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 alcohols is preferably 0.1 to 5% by mass in the polishing liquid composition or a diluent obtained by diluting the polishing liquid composition with an aqueous medium.

<Chelating agent>
As the chelating agent, ethylenediaminetetraacetic acid, sodium ethylenediaminetetraacetate, nitrilotriacetic acid, sodium nitrilotriacetate, ammonium nitrilotriacetate, hydroxyethylethylenediaminetriacetate, sodium hydroxyethylethylenediaminetriacetate, triethylenetetraminehexaacetic acid, triethylenetetramine Sodium hexaacetate and the like can be mentioned. The content of the chelating agent is preferably 0.01 to 1% by mass in the polishing liquid composition or a diluent obtained by diluting the polishing liquid composition with an aqueous medium.

<Nonionic surfactant>
As the nonionic surfactant, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbit fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl phenyl ether, Examples thereof include polyethylene glycol type such as oxyalkylene (hardened) castor oil, polyhydric alcohol type such as sucrose fatty acid ester, polyglycerin alkyl ether, polyglycerin fatty acid ester and alkyl glycoside, and fatty acid alkanolamide.

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

[Preparation method of silica particle dispersion]
The silica particle dispersion is obtained by subjecting a mixed liquid obtained by mixing silica particles (component A), a basic compound (component B) and an aqueous medium to an aging step of maintaining the temperature at a predetermined temperature for a predetermined time. .. The silica particles (component A), the basic compound (component B) and the aqueous medium can be mixed 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 agglomeration of silica particles are contained in the aqueous medium, it is preferable to remove the coarse particles by centrifugation or filtration using a filter.

The predetermined temperature in the aging step is 10° C. or higher from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer, but is preferable from the viewpoint of shortening the aging time and improving productivity. Is 30° C. or higher and is 80° C. or lower from the viewpoint of storage stability, but is preferably 60° C. or lower. The predetermined time is 1 day (1 day (24 hours)±6 hours) or more, and 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 productivity improvement. Time) or less, more preferably 8 days (8 days (192 hours)±6 hours) or less. Further, the predetermined time is more preferably 12 days (12 days (288 hours)±6 hours) or more, and even 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 It is more preferably 80 days (80 days (1920 hours)±6 hours) or more. When the predetermined temperature in the aging step 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, even more preferably 12 days (12 days (288 hours)±6 hours) or more, even more 28 days (28 days (672 hours)±6 hours) or more, more preferably 40 days (40 days (960 hours)±6 hours) or more, and still 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 constituents of the silica particle dispersion are completely mixed, and is the time elapsed from that time to the time before the mixing with the additive aqueous solution is started. Therefore, the "predetermined time" includes not only the time stored in a warehouse or the like, but also the transportation time when transportation 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 the mixed liquid obtained by mixing the silica particles (component A), the basic compound (component B) and the aqueous medium is possible from the viewpoint of reducing surface defects (LPD) and surface roughness (haze). As long as it is filled with the container so that air and light cannot enter, it is preferable.

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

[Method for preparing polishing liquid composition]
It is prepared by mixing the above-mentioned silica particle dispersion liquid of the polishing liquid composition of the present invention and an additive aqueous solution. The method for preparing the polishing composition is not particularly limited, but from the viewpoint of enhancing the dispersion stability of silica particles, it is preferable to add the silica particle dispersion to the additive aqueous solution and mix them. Further, from the viewpoint of enhancing the dispersibility of silica particles, it is preferable to add the silica particle dispersion liquid to the mixture while stirring the aqueous additive solution, and mix them. It is also possible to prepare by adding an aqueous medium separately from the silica particle dispersion and the additive aqueous solution. During or after the preparation of the polishing composition, use a general dispersion or particle removal method for the purpose of efficiently and economically removing coarse particles contained in the silica particle dispersion or the polishing composition. You can

<Method for polishing silicon wafer to be polished, method for manufacturing semiconductor substrate>
One aspect of the method for polishing a silicon wafer to be polished of the present invention (hereinafter sometimes referred to as "the polishing method of the present invention") and the method for producing a semiconductor substrate of the present invention (hereinafter referred to as "the production method of the present invention") In one embodiment, a step of polishing a silicon wafer to be polished with the polishing composition of the present invention as it is or a polishing composition obtained by diluting the polishing composition of the present invention with an aqueous medium. including. Further, in another aspect of the polishing method of the present invention and another aspect of the production method of the present invention, the silica particle dispersion liquid (first liquid) and the additive aqueous solution (which constitute the polishing liquid composition preparation kit of the present invention ( Second liquid), and then diluted with an aqueous medium as necessary, or either one of the silica particle dispersion liquid (first liquid) and the additive aqueous solution (second liquid) as necessary, or The method includes the step of diluting both with an aqueous medium and then polishing a silicon wafer to be polished with a polishing composition obtained by mixing these. The amounts of the silica particle dispersion and the additive aqueous solution to be used 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-pack type 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. When it is directly used for polishing without going through the aging step of holding it at 1, 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, the silica particle dispersion liquid containing the silica particles in which the hydrated layer is highly stabilized, or the freeze-dried BET specific surface area is divided by the BET specific surface area of the air-dried silica particles. A polishing liquid composition prepared by using a silica particle dispersion liquid having a value of 1.3 or more and 10 or less (including a polishing liquid composition prepared by using the polishing liquid 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 a polishing composition.

In the step of polishing the silicon wafer to be polished, a lapping (rough polishing) step of 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 finish polishing step of mirror-finishing the surface of the silicon wafer. The polishing composition of the present invention is more preferably used in the final 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 means the pressure of the surface plate applied to the surface to be polished of the silicon wafer to be polished during 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 preferable. 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 manufacturing method of the present invention and the polishing method of the present invention further include a step of cleaning the polished silicon wafer to be polished after the step of polishing the silicon wafer to be polished using the polishing composition.

The method for producing a semiconductor substrate of the present invention includes a step of polishing a silicon wafer to be polished using the silicon wafer polishing composition composition kit. Here, "using the polishing composition composition kit for silicon wafers" means the silica particle dispersion (first solution) and the aqueous additive solution (second solution) of the above-mentioned "polishing composition composition kit for silicon wafers". After mixing, dilute with aqueous medium as needed, or dilute either or both of silica particle dispersion (first liquid) and aqueous solution of additive (second liquid) with aqueous medium as needed. And then using the polishing composition obtained by mixing these.

The method for polishing a silicon wafer to be polished of the present invention includes a step of polishing a silicon wafer to be polished using the polishing liquid composition kit for a silicon wafer. Here, "using the polishing composition composition kit for silicon wafers" means the silica particle dispersion (first solution) and the aqueous additive solution (second solution) of the above-mentioned "polishing composition composition kit for silicon wafers". After mixing, dilute with aqueous medium as needed, or dilute either or both of silica particle dispersion (first liquid) and aqueous solution of additive (second liquid) with aqueous medium as needed. And then using the polishing composition obtained by mixing these.

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

<1> A polishing liquid composition for a silicon wafer obtained by mixing a silica particle dispersion liquid containing silica particles, a basic compound and an aqueous medium, and an additive aqueous solution containing a water-soluble polymer compound and an aqueous medium. There
The transmittance of light having a wavelength of 600 nm of the silica particle dispersion is 5.0% or more, more preferably 5% or more when the content of the silica particles is 5% by mass or more and 20% by mass or less.
% Or more, more preferably 8.0% or more, even more preferably 8% or more, even more preferably 11% or more, 30% or less, preferably 24% or less, more preferably 16% or less, silicon Wafer polishing composition.
<2> The polishing liquid composition for a silicon wafer according to <1>, wherein the silica particle dispersion has a pH at 25° C. of 9 or more and 11 or less.
<3> A polishing liquid composition for silicon wafer obtained by mixing a silica particle dispersion liquid containing silica particles, a basic compound and an aqueous medium, and an additive aqueous solution containing a water-soluble polymer compound and an aqueous medium. There
The transmittance of light having a wavelength of 600 nm of the silica particle dispersion has a pH of the silica particle dispersion at 25° C. of 9 or more and 11 or less, preferably pH 10±0.3, and the content of the silica particles is 10% by mass. If the amount is 15% by mass or more and preferably 10% by mass or less, 5.
0% or more, more preferably 5% or more, even more preferably 8.0% or more, even more preferably 8% or more, still more preferably 11% or more, 30% or less, preferably 24% or less, more preferably Is 16% or less, a polishing liquid composition for silicon wafers.
<4> A polishing liquid composition for a silicon wafer obtained by mixing a silica particle dispersion liquid containing silica particles, a basic compound and an aqueous medium, and an additive aqueous solution containing a water-soluble polymer compound and an aqueous medium. There
The transmittance of light having a wavelength of 600 nm of the silica particle dispersion is 5.0% or more and 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 A polishing liquid composition for silicon wafers, which is 10% by mass or more and 15% by mass or less.
<5> A polishing liquid composition for a silicon wafer obtained by mixing a silica particle dispersion liquid containing silica particles, a basic compound and an aqueous medium, and an additive aqueous 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 or more. A polishing liquid composition for silicon wafers, which is 0.0 or less, more preferably 3.0 or less.
<6> 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, and further preferably 2.4 mmol/g or more. , Preferably 10 mmol/g or less, more preferably 5.0 mmo
The polishing liquid composition for silicon wafer according to <5>, which is 1/g or less, and more preferably 3.0 mmol/g or less.
<7> The porosity of the silica particle surface after the freeze-drying is preferably 1.5% or more, more preferably 4.0% or more, still more preferably 6.0% or more, preferably 30% or less. , More preferably 20% or less, further preferably 15% or less, the polishing liquid composition for silicon wafer according to <5> or <6>.
<8> The BET specific surface area of the freeze-dried silica particles is 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 250 meters ² /
The polishing liquid composition for a silicon wafer according to any one of <5> to <7>, which is g or less.
<9> The water-soluble polymer compound is preferably at least one selected from the group consisting of polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, polyethylene glycol, polyoxyethylene, HEAA homopolymer, and a copolymer of NIPAM and AAm. Water-soluble polymer compound, more preferably polyvinyl alcohol, hydroxyethyl cellulose, HEAA homopolymer, and at least one water-soluble polymer compound selected from the group consisting of NIPAM and AAm copolymer, The polishing liquid composition for a silicon wafer 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, further preferably 20,000 or more, preferably 150,000 or less, more preferably 100,000 or less, further The polishing liquid composition for silicon wafer according to <9>, which is preferably 80,000 or less.
<11> The weight average molecular weight of the polyvinylpyrrolidone is preferably 10,000 or more, more preferably 30,000 or more, further preferably 200,000 or more, preferably 1 million or less, more preferably 700,000 or less, further preferably The polishing liquid composition for a silicon wafer 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, still more preferably 240,000 or more, preferably 1.5 million or less, more preferably 1.1 million or less, further preferably The polishing liquid composition for a silicon wafer 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, even more preferably 200,000 or more, even more preferably 300,000 or more, even more preferably 400,000 or more. And preferably 2 million or less, more preferably 1.5 million or less, even more preferably 1 million or less, even more preferably 900,000 or less, even more preferably 800,000 or less, the silicon wafer according to <9> 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 or more. 10,000 or less, more preferably 800,000 or less, further preferably 600,000 or less, and the polishing liquid composition for a silicon wafer according to <9>.
<15> Preferably, the polishing liquid 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 diameter of the silica particles is preferably 5 nm or more, more preferably 10 nm or more, even more preferably 15 nm or more, even more preferably 20 nm or more, preferably 50 nm or less, more preferably 45 nm or less, The polishing liquid composition for silicon wafer according to any one of <1> to <15>, which is more preferably 40 nm or less.
<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, even more preferably 0.015 or more, preferably 1.0 or less, more preferably 0.8 or less, even more preferably 0.6 or less, even more preferably Is 0.4 or less, and more preferably 0.3 or less. The polishing composition for silicon wafer according to any one of <1> to <16>.
<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 liquid composition for a silicon wafer according to any one of <1> to <17>.
<19> A silica particle dispersion liquid (first liquid) containing silica particles, a basic compound, and an aqueous medium, and an additive aqueous 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 liquid (first liquid) is 5.0% or more, and more preferably 5.0% by mass or more and 20% by mass or less. Is 5% or more, more preferably 8.0% or more, even more preferably 8% or more, even more preferably 11% or more, 30% or less, preferably 24% or less, more preferably 16% or less. A polishing liquid composition kit for a silicon wafer.
<20> The polishing composition composition kit 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 liquid (first liquid) containing silica particles, a basic compound, and an aqueous medium, and an additive aqueous solution (second liquid) containing a water-soluble polymer compound and an aqueous medium,
The silica particle dispersion liquid (first liquid) has a transmittance of light having a wavelength of 600 nm at 25° C. of the silica particle dispersion liquid of 9 or more and 11 or less, preferably pH 10±0.3, and the silica particles are contained. When 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, further preferably 8.0% or more, still more preferably 8% or more. The polishing liquid composition kit for silicon wafers is still more preferably 11% or more, 30% or less, preferably 24% or less, more preferably 16% or less.
<22> A silica particle dispersion liquid (first liquid) containing silica particles, a basic compound, and an aqueous medium, and an additive aqueous 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 or more. A polishing liquid composition kit for silicon wafers, which is 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, and preferably Is 10 mmol/g or less, more preferably 5.0 mmol/g or less, and further preferably 3.0 mmol/g or less, the polishing composition kit for a silicon wafer according to <22>.
<24> The porosity of the surface of the freeze-dried silica particles is preferably 1.5% or more, more preferably 4.0% or more, further preferably 6.0% or more, preferably 30% or less, The polishing liquid composition kit for a silicon wafer according to <22> or <23>, which is preferably 20% or less, more preferably 15% or less.
<25> The BET specific surface area of the freeze-dried silica particles is 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 250 meters ² /
The polishing liquid composition kit for a silicon wafer according to any one of <22> to <24>, which is not more than g.
<26> The water-soluble polymer compound is preferably at least selected from the group consisting of polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, polyethylene glycol, polyoxyethylene, HEAA homopolymer, and a copolymer of NIPAM and AAm. Containing one water-soluble polymer compound, more preferably polyvinyl alcohol, hydroxyethyl cellulose, HEAA homopolymer and at least one water-soluble polymer compound selected from the group consisting of copolymers of NIPAM and AAm, The polishing liquid composition kit 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, further preferably 20,000 or more, preferably 150,000 or less, more preferably 100,000 or less, further The polishing liquid composition kit for a silicon wafer according to <26>, which is 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, further preferably 200,000 or more, preferably 1 million or less, more preferably 700,000 or less, further preferably The polishing liquid composition kit for a silicon wafer 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, further preferably The polishing liquid composition kit for a silicon wafer 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, still more preferably 400,000 or more. And preferably 2 million or less, more preferably 1.5 million or less, even more preferably 1 million or less, even more preferably 900,000 or less, even more preferably 800,000 or less, the silicon wafer according to <26> 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 or more. The polishing liquid composition kit for a silicon wafer according to <26>, which is 10,000 or less, more preferably 800,000 or less, and further preferably 600,000 or less.
<32> Preferably, the polishing liquid composition kit 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 the silica particles contained in the silica particle dispersion is preferably 3% by mass or more, more preferably 5% by mass or more, further preferably 8% by mass or more, and preferably 25% by mass or less, The polishing liquid composition kit for a silicon wafer according to any one of <19> to <32>, which is more preferably 20% by mass or less, and further preferably 15% by mass or less.
<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. Or more, preferably 5 mass% or less, more preferably 4 mass% or less, still more preferably 3 mass% or less, the polishing liquid composition for a silicon wafer according to any one of <19> to <33>. kit.
<35> The mass ratio of the silica particles and the basic compound contained in the silica particle dispersion (silica particles/basic compound) is preferably 0.6 or more, more preferably 1 or more, further preferably 3 or more. The polishing liquid composition kit for a silicon wafer according to any one of <19> to <34>, which is preferably 500 or less, more preferably 200 or less, still more preferably 100 or less.
<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, further preferably 1.5% by mass or more, preferably Is 20% by mass or less, more preferably 15% by mass or less, still more preferably 12% by mass or less, and the polishing composition composition kit for a silicon wafer according to any one of <19> to <35>.
<37> A method for producing a polishing liquid composition for a silicon wafer, which comprises 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 additive aqueous 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. Below, 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 (1
92 hours)±6 hours) or less to obtain a silica particle dispersion liquid,
A method for producing a polishing liquid composition for a silicon wafer, comprising the step of mixing the silica particle dispersion and the additive aqueous solution.
<38> The content of the silica particles contained in the silica particle dispersion is preferably 3% by mass or more, more preferably 5% by mass or more, further preferably 8% by mass or more, and preferably 25% by mass or less, The method for producing a polishing composition for silicon wafer according to <37>, which is more preferably 20% by mass or less, and further preferably 15% by mass or less.
<39> A method for manufacturing 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 additive aqueous 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 the silica particles contained in the silica particle dispersion is preferably 3% by mass or more, more preferably 5% by mass or more, further preferably 8% by mass or more, and preferably 25% by mass or less, The method for producing a polishing composition composition kit for a silicon wafer according to <39>, which is more preferably 20% by mass or less, and further preferably 15% by mass or less.
<41> A silica particle dispersion liquid containing silica particles, a basic compound, and an aqueous medium,
The transmittance of light having a wavelength of 600 nm of the silica particle dispersion is 5.0% or more, more preferably 5% or more when the content of the silica particles is 5% by mass or more and 20% by mass or less.
% Or more, more preferably 8.0% or more, even more preferably 8% or more, even more preferably 11% or more, 30% or less, preferably 24% or less, more preferably 16% or less, silica Particle dispersion.
<42> A silica particle dispersion liquid containing silica particles, a basic compound, and an aqueous medium,
The transmittance of light having a wavelength of 600 nm of the silica particle dispersion has a pH of the silica particle dispersion at 25° C. of 9 or more and 11 or less, preferably pH 10±0.3, and the content of the silica particles is 10% by mass. If the amount is 15% by mass or more and preferably 10% by mass or less, 5.
0% or more, more preferably 5% or more, even more preferably 8.0% or more, even more preferably 8% or more, still more preferably 11% or more, 30% or less, preferably 24% or less, more preferably Is 16% or less, a silica particle dispersion liquid.
<43> A silica particle dispersion liquid 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 or more. A silica particle dispersion liquid, which is 0.0 or less, more preferably 3.0 or less.
<44> A polishing liquid for silicon wafer, including a step of mixing the silica particle dispersion liquid according to any one of <41> to <43> and an additive aqueous solution containing a water-soluble polymer compound and an aqueous medium. A method for producing a 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 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 a 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, which comprises a step of polishing a silicon wafer to be polished using the polishing composition composition kit for a 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 a silicon wafer to be polished using the polishing composition composition kit for a 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 homopolymers used for preparation of polishing liquid compositions of Examples 1 to 22 and Comparative Examples 1 and 2 below are It was synthesized as follows.

150 g of hydroxyethyl acrylamide (1.30 mol manufactured by Kojin) was dissolved in 100 g of ion-exchanged water to prepare a monomer aqueous solution. Separately, 70 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride 0.035 g (polymerization initiator, V-50 1.30 mmol manufactured by Wako Pure Chemical Industries)
Was dissolved in ion-exchanged water to prepare a polymerization initiator aqueous solution. 1180 g of ion-exchanged water was put into a 2 L separable flask equipped with a Dimroth condenser, a thermometer and a stirring blade made of Crescent Teflon (registered trademark), and then the inside of the separable flask was replaced with nitrogen. Then, the temperature in the separable flask was raised to 68° C. using an oil bath, and the monomer aqueous solution and the polymerization initiator aqueous solution prepared in advance were stirred in a separable flask for 3.5 hours, respectively. Dropped. After completion of the dropping, 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) was used as the water-soluble polymer compound, and in Example 24 and Comparative Example 4, water-soluble Polyvinylpyrrolidone (PVP, weight average molecular weight 360,000, K-60 manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the polymer compound, and 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 and PVA105 manufactured by Kuraray Co., Ltd. were used.

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

In a 500 ml separable flask equipped with a thermometer and a 5 cm crescent-shaped Teflon (registered trademark) stirring blade, isopropylacrylamide 40 g (0.35 mol manufactured by Kojin), acrylamide 10 g (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. Then, nitrogen was blown into the solution for 30 minutes at 50 ml/min. On the other hand, 0.043 g of L-ascorbic acid (polymerization initiator, 0.25 mmol manufactured by Wako Pure Chemical Industries) and 24.93 g of ion-exchanged water are mixed in a 50 ml beaker, and L-ascorbic acid is dissolved in ion-exchanged water to prepare L-ascorbic acid. An acid solution was obtained, which was sparged with nitrogen for 30 minutes at 50 ml/min. Then, a solution containing isopropylacrylamide and acrylamide in a 500 ml separable flask was added dropwise with the L-ascorbic acid solution blown with nitrogen at 25°C over 30 minutes, and then at 25°C, 200 rpm (peripheral speed 1.05 m/s
) And stirred for 1 hour. Furthermore, the temperature was raised to 40° C. and the mixture was stirred for 1 hour. After adding 100 ml of ion-exchanged water to the solution in the separable flask, add it dropwise to 4 L of acetone (manufactured by Wako Pure Chemical Industries), and add NIP.
A copolymer (solid) of NIPAM and AAm having a weight ratio of AM to AAm of 80:20 was obtained. The obtained solid was dried at 70° C./1 KPa or less to obtain 42.7 g of a semitransparent solid (a copolymer of NIPAM and AAm (weight average molecular weight 400000, yield 85%)).

2. Measuring 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>
Device: HLC-8320 GPC (Tosoh Corporation, detector integrated type)
Column: GMPWXL+GMPWXL (anion)
Eluent: 0.2M phosphate buffer/CH ₃ CN=9/1
Flow rate: 0.5 ml/min
Column temperature: 40℃
Detector: Shoredex RI SE-61 Differential refractive index detector Standard substance: Monodisperse polyethylene glycol with known molecular weight

<Measurement of water solubility>
Regarding the water solubility of each water-soluble polymer compound, 0.5 g/100 ml of a water-soluble polymer compound aqueous solution was prepared, and the state was visually confirmed 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) 0.5 g of a water-soluble polymer compound is weighed and put into a screw tube.
(3) After stirring at room temperature for 3 hours, the temperature is elevated to 70° C. and stirring is continued for 3 hours.
(4) After cooling to room temperature, add water to make 100 ml.
(5) Visually check the state of the aqueous solution. If 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 material (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

Regarding the specific surface area of the abrasive material, after performing the following [pretreatment], about 0.1 g of the measurement sample was precisely measured in the measurement cell to 4 digits after the decimal point, and immediately before the measurement of the specific surface area, in an atmosphere of 110° C. for 30 minutes. After drying, it was measured by a nitrogen adsorption method (BET method) using a specific surface area measuring device (Micromeritic automatic specific surface area measuring device Flowsorb III2305, 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 material 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 crushed sample is suspended in ion-exchanged water at 40° C. and filtered with 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-exchanged water (40° C.).
(F) The filter to which the filtered material is attached is placed in a petri dish and dried in an atmosphere at 110° C. for 4 hours.
(G) The dried filtered material (abrasive grains) was taken so as not to mix filter dust, and finely ground in a mortar to obtain a measurement sample.

<Average secondary particle diameter of abrasive (silica particles)>
The average secondary particle diameter (nm) of the abrasive was such that the abrasive was added to ion-exchanged water so that the concentration of the abrasive was 0.25% by mass, and the obtained aqueous dispersion was treated with Disposable Sizin.
It was placed in a g Cuvette (10 mm cell made of polystyrene) 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.), then at a freezing temperature of -45°C and a drying pressure of 10 Pa. And lyophilized for 48 hours. The freeze-dried product thus obtained was finely pulverized using an agate mortar to obtain a measurement sample. Approximately 0.1 g of the obtained measurement sample was accurately measured in the measurement cell to 4 digits after the decimal point and dried for 30 minutes in an atmosphere of 110° C. immediately before measuring the specific surface area. The specific surface area (m ² /g) of the freeze-dried silica particles was measured by a nitrogen adsorption method (BE) using a specific surface area measuring apparatus Flowsorb III2305, manufactured by Shimadzu Corporation.
T method).

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

<Measurement of silanol group content>
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 to 25 to 700° C. at a rate of 10° C./min under an air flow (300 mL/min), and the balance of the mass measured at 200° C. was the weight of SiO ₂ (g), 200. The weight loss during heating up to ˜700° C. was measured as the weight of silanol-derived water (g), and the amount of silanol groups (mmol/g) was calculated using the following formula.
Amount of silanol groups (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 carried out by a multipoint method using liquid nitrogen. The sample (freeze-dried silica particles) to be subjected to the nitrogen gas adsorption measurement was pretreated by heating at 200° C. for 2 hours before the nitrogen gas adsorption measurement. The porosity (%) of the micropores was calculated from the pore volume (mL/g) of the micropores determined by the t-plot method and the silica density (2.2 g/mL) using the following formula.
Porosity (%)=100×pore volume/(1/2.2+pore volume)

3. Method for preparing silica particle dispersion For ion-exchanged water, silica particles (colloidal silica, Na content 45 ppb/solid content,
An average primary particle diameter of 35 nm, an average secondary particle diameter of 71.8 mm, an association degree of 2.1) and, if necessary, 28% by mass aqueous ammonia (Kishida Chemical Co., Ltd. reagent special grade) were added, and these were stirred for 30 minutes. Immediately after mixing to obtain a mixed liquid, the mixed liquid was immediately filled into a 5 L molded liquid container Fujitainer (registered trademark) (manufactured by Fujimori Kogyo Co., Ltd.) so that air did not enter, and the mixed liquid was described in Table 1. It preserve|saved on storage conditions (temperature of a liquid mixture, period), and obtained the silica particle dispersion liquid for Examples 1-26 and Comparative Examples 1-6. The content of silica particles in the mixed solution was 10% by mass, and the content of ammonia was adjusted so that the value of pH (25° C.) of the silica particle dispersion was as shown in Table 1. The "period" described in Table 1 is the "preservation time", which was counted from the time when the stirring was sufficiently completed (for example, 30 minutes) until the concentration of the constituents of the silica particle dispersion became uniform. ..

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

4. Method for Preparing Additive Aqueous Solution The water-soluble polymer compounds shown in Table 1 were added to ion-exchanged water to obtain additive aqueous 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. Method for Preparing Polishing Liquid Composition The silica particle dispersion and the additive aqueous solution were mixed so that the content of the silica particles was 0.17% by mass and the content of the water-soluble polymer compound was 0.02% by mass. Then, an aqueous medium was further mixed to obtain polishing liquid compositions of Examples 1 to 26 and Comparative Examples 1 to 6.

6. Polishing Method Immediately after the polishing liquid composition obtained by mixing the silica particle dispersion liquid and the additive aqueous solution as described above was prepared, it was used for the final polishing under the following polishing conditions ([finishing polishing conditions]). The object to be polished is a silicon wafer (a silicon single-sided mirror-finished wafer having a diameter of 200 mm, conductivity type: P, crystal orientation: 100, resistivity of 0.1 Ω·cm or more and less than 100 Ω·cm). Prior to the final polishing, rough polishing was performed on a silicon wafer in advance using a commercially available polishing composition. The surface roughness (haze) of the silicon wafer after 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 conditions]
Polishing machine: Single-sided 8-inch polishing machine GRIND-X SPP600s (Okamoto Manufacturing)
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
Plate rotation speed: 60 rpm
Polishing time: 10 minutes Supply rate of abrasive composition: 200 ml/min per silicon wafer
Abrasive composition temperature: 20°C
Carrier rotation speed: 60 rpm

7. Cleaning Method After finishing polishing, the silicon wafer was subjected to ozone cleaning and diluted hydrofluoric acid cleaning as follows. In ozone cleaning, pure water containing 20 ppm ozone is 600 rpm at a flow rate of 1 L/min from the nozzle.
Sprayed for 3 minutes toward the center of the rotating silicon wafer. At this time, the temperature of the ozone water was normal temperature. Then, dilute hydrofluoric acid cleaning was performed. In cleaning with dilute hydrofluoric acid, pure water containing 0.5% ammonium hydrogen fluoride (special grade: Nacalai Tex Co., Ltd.) 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 6 seconds. The ozone cleaning and the diluted hydrofluoric acid cleaning were performed as one set, and a total of two sets were performed, and finally spin drying was performed. 150 for spin drying
The silicon wafer was rotated at 0 rpm.

8. Various evaluations (1) Evaluation of surface defects (LPD) and surface roughness (haze) on the surface of the silicon wafer The surface roughness (haze) of the surface of the silicon wafer after cleaning is the surface roughness measuring device "Surfscan SP1" (KLA Tencor) Darkfield wide oblique incidence channel (DWO) measured using
) Value was used. The surface defects (LPD) were also measured at the same time as the Haze measurement, and evaluated by measuring the number of particles having a particle size of 50 nm or more on the surface of the silicon wafer. The smaller the number of surface defects (LPD), the lesser the number of surface defects. In addition, the polishing liquid compositions of Examples 1 to 26 and Comparative Examples 2 to 6 were respectively treated with a mixed liquid of the same composition containing silica particles, a basic compound, a water-soluble polymer compound, and an aqueous medium. The values of surface defects (LPD) and Haze (DWO) in the case of using a one-pack type polishing composition obtained by storing (aging) for 2 weeks at the same storage temperature as in Examples and Comparative Examples The surface defects (LPD) and Haze when the polishing liquid compositions of Examples 1 to 26 and Comparative Examples 2 to 6 were used for polishing according to the following evaluation criteria, with these values being 1.0 (reference values) respectively. (DWO) was evaluated. In the polishing composition of Comparative Example 1, the silica particles were agglomerated so much that the surface defects (LPD) and the surface roughness (haze) could not be evaluated.

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

(2) Wettability The area of the hydrophilic portion (wet portion) of the mirror surface of the silicon wafer (diameter 200 mm) immediately after finish polishing was visually observed. The measurement was performed on two different silicon wafers, and the average value was evaluated according to the following evaluation criteria, and the results are shown in Table 1. The polishing composition of Comparative Example 1 could not be evaluated for wettability because the silica particles were agglomerated severely.
(Evaluation criteria)
A: Wetting portion area ratio is 95 or more B: Wetting portion area ratio is 90% or more and less than 95% C: Wetting portion area ratio is 50% or more and less than 90% D: Wetting portion area ratio is less than 50%

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

INDUSTRIAL APPLICABILITY The present invention is capable of stably reducing the surface roughness (haze) and surface defects (LPD) of a polished silicon wafer surface, and is useful in mass production of semiconductor substrates.

Claims (25)

A polishing liquid composition for a silicon wafer obtained by mixing a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an additive aqueous solution 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 is 5.0% or more and 30% or less in any case where the content of the silica particles is 5% by mass or more and 20% by mass or less,
Polishing liquid composition for silicon wafer. A polishing liquid composition for a silicon wafer obtained by mixing a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an additive aqueous solution 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 is such that the pH of the silica particle dispersion at 25° C. is 9 or more and 11 or less, and the content of the silica particles is 10% by mass or more and 15% by mass or less. In some cases, the polishing liquid composition for silicon wafer is 5.0% or more and 30% or less. A polishing liquid composition for a silicon wafer obtained by mixing a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an additive aqueous solution 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 is 5.0% or more and 30% or less, the pH of the silica particle dispersion at 25° C. is 9 or more and 11 or less, and the content of the silica particles is 10 or less. A polishing liquid composition for silicon wafers, which is contained in an amount of from 15% by mass to 15% by mass. A polishing liquid composition for a silicon wafer obtained by mixing a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an additive aqueous 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 liquid composition for a silicon wafer 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. The polishing liquid 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 liquid composition for a silicon wafer according to claim 4 or 5, wherein the 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, polyvinylpyrrolidone, hydroxyethyl cellulose, polyethylene glycol, polyoxyethylene, a homopolymer of N-hydroxyethyl acrylamide (HEAA), and N-isopropyl acrylamide (NIPAM) and acrylamide (AAm). The polishing liquid composition for silicon wafers according to claim 1, comprising at least one water-soluble polymer compound selected from the group consisting of copolymers with. Furthermore, the polishing liquid composition for silicon wafers according to any one of claims 1 to 7, wherein the aqueous additive solution contains a polyoxyalkylene compound. A silica particle dispersion liquid containing silica particles, a basic compound and an aqueous medium (first liquid), and an additive aqueous solution containing a water-soluble polymer compound and an aqueous medium (second liquid),
The transmittance of light having a wavelength of 600 nm of the silica particle dispersion liquid (first liquid) is 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. A polishing liquid composition kit for a silicon wafer. A silica particle dispersion liquid containing silica particles, a basic compound and an aqueous medium (first liquid), and an additive aqueous solution containing a water-soluble polymer compound and an aqueous medium (second liquid),
The transmittance of light having a wavelength of 600 nm of the silica particle dispersion liquid (first liquid) is such that the pH of the silica particle dispersion liquid at 25° C. is 9 or more and 11 or less, and the content of the silica particles is 10% by mass or more and 15% by mass. A polishing liquid composition kit for a silicon wafer, which is 5.0% or more and 30% or less in any of the following cases. A silica particle dispersion liquid containing silica particles, a basic compound and an aqueous medium (first liquid), and an additive aqueous solution containing a water-soluble polymer compound and an aqueous medium (second liquid),
The BET specific surface area of freeze-dried silica particles obtained by freeze-drying the silica particles in the silica particle dispersion, 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 BET specific surface area of 1.3 to 10 kit. The polishing composition composition kit for a silicon wafer according to claim 11, wherein the amount of silanol groups per unit mass of the silica particles after the freeze-drying is 2.1 mmol/g or more and 10 mmol/g or less. The polishing composition composition kit for a silicon wafer according to claim 11 or 12, wherein the porosity of the silica particles after freeze-drying is 1.5% or more and 30% or less. The water-soluble polymer compound is a homopolymer of polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, polyethylene glycol, polyoxyethylene, N-hydroxyethyl acrylamide (HEAA), and N-isopropyl acrylamide (NIPAM) and acrylamide (AAm). The polishing composition composition kit for a silicon wafer according to claim 9, further comprising at least one water-soluble polymer compound selected from the group consisting of copolymers with. Furthermore, the polishing liquid composition kit for a silicon wafer according to claim 9, wherein the additive aqueous solution contains a polyoxyalkylene compound. A method for producing a silicon wafer polishing liquid composition containing 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 additive aqueous 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° C. or more and 80° C. or less for 1 day or more. When,
A method for producing a polishing liquid composition for a silicon wafer, comprising the step of mixing the silica particle dispersion and the additive aqueous solution. A method for manufacturing the polishing composition composition kit for a silicon wafer according to claim 9,
A step of mixing a water-soluble polymer compound and an aqueous medium to obtain an additive aqueous solution,
The pH at 25° C. obtained by mixing silica particles, a basic compound and an aqueous medium is 9 or more 1
A method for producing a polishing composition composition kit for a silicon wafer, comprising the step of maintaining a mixed solution of 1 or less at 10° C. or higher and 80° C. or lower for 1 day or longer to obtain a silica particle dispersion. A silica particle dispersion containing silica particles, a basic compound, and an aqueous medium,
The transmittance of light having a wavelength of 600 nm of the silica particle dispersion is such that the pH of the silica particle dispersion at 25° C. is 9 or more and 11 or less and the content of the silica particles is 10% by mass or more and 15% by mass or less. In some cases, the silica particle dispersion liquid is 5.0% or more and 30% 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 liquid 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 liquid 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 liquid composition for a silicon wafer, comprising the step of mixing the silica particle dispersion liquid according to any one of claims 18 to 20 and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. A method for producing a semiconductor substrate, comprising the step of polishing a silicon wafer to be polished using the polishing composition for silicon wafer according to claim 1. A method for polishing a silicon wafer to be polished, comprising the step of polishing a silicon wafer to be polished using the polishing composition for silicon wafer according to claim 1. A method for producing a semiconductor substrate, comprising the step of polishing a silicon wafer to be polished using the polishing composition composition kit for a silicon wafer according to claim 9. A method of polishing a silicon wafer to be polished, which comprises a step of polishing a silicon wafer to be polished using the polishing composition composition kit for silicon wafer according to claim 9.