JP6836671B2 - Polishing liquid composition for silicon wafer or polishing liquid composition kit for silicon wafer - Google Patents

Description

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

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

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

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

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

Japanese Unexamined Patent Publication No. 2013-222863 Japanese Unexamined Patent Publication No. 2004-128089 Japanese Unexamined Patent Publication No. 11-116942 WO2014 / 148399

However, when the concentrated polishing liquid composition is diluted and then used for polishing a silicon wafer, or after mixing the liquids constituting the two-component polishing liquid composition, the obtained polishing liquid composition is made into silicon. When used for polishing wafers, the reduction of surface roughness (haze) and surface defects (LPD) on the polished silicon wafer surface was sometimes insufficient.

In the present invention, a polishing liquid composition for a silicon wafer capable of stably reducing the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface, a method for producing the same, and a polishing liquid composition for the silicon wafer. Provided is a method for polishing a silicon wafer to be polished and a method for manufacturing a semiconductor substrate using an object. Further, in the present invention, a polishing liquid composition kit for a silicon wafer capable of stably reducing the surface roughness (haze) and surface defects (LPD) of the surface of the polished silicon wafer, a manufacturing method thereof, and the silicon wafer. Provided is a method for polishing a silicon wafer to be polished and a method for manufacturing a semiconductor substrate using a polishing liquid composition kit. The present invention also provides a silica particle dispersion used for preparing a polishing liquid composition for a silicon wafer capable of stably reducing the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface. To do.

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

Another aspect 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 light transmittance of the silica particle dispersion liquid at a wavelength of 600 nm is any one of 5% by mass or more and 20% by mass or less of the content of the silica particles. In some cases, it is 5.0% or more and 30% or less.

Another aspect of the polishing liquid composition for a silicon wafer of the present invention is 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. A polishing liquid composition for a silicon wafer obtained by mixing, wherein the light transmittance of the silica particle dispersion liquid at a wavelength of 600 nm is 5.0% or more and 30% or less, and the silica particle dispersion liquid is 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 aspect 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. The BET specific surface area of the freeze-dried silica particles obtained by freeze-drying the silica particle dispersion liquid in the polishing liquid composition for a silicon wafer obtained by mixing was obtained by air-drying the silica particle dispersion liquid. The BET specific surface area ratio (BET specific surface area of the freeze-dried silica particles / BET specific surface area of the air-dried silica particles) obtained by dividing by the BET specific surface area of the air-dried silica particles is 1.3 or more and 10 or less.

One aspect of the polishing liquid composition kit for silicon wafers of the present invention includes a silica particle dispersion liquid (first liquid) containing silica particles, a basic compound, and an aqueous medium, and a water-soluble polymer compound and an aqueous medium. The silica particle dispersion liquid (first liquid) containing the additive aqueous solution (second 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, and a water-soluble polymer compound and an aqueous medium. When the light transmittance of the silica particle dispersion liquid (first liquid) having a wavelength of 600 nm is 5% by mass or more and 20% by mass or less, which contains the additive aqueous solution (second liquid) containing the silica particles. 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, and a water-soluble polymer compound and an aqueous medium. The silica particle dispersion liquid (first liquid) contains the additive aqueous solution (second liquid) containing the mixture, and the light transmittance of the silica particle dispersion liquid (first liquid) at a wavelength of 600 nm is such that the pH of the silica particle dispersion liquid at 25 ° C. is 9 or more and 11 or less. The content of the silica particles is 5.0% or more and 30% or less in any case of 10% by mass or more and 15% by mass or less.

In another aspect of the polishing liquid composition kit for silicon wafers of the present invention, a silica particle dispersion liquid (first liquid) containing silica particles, a basic compound, and an aqueous medium, and a water-soluble polymer compound and an aqueous medium are used. Air-dried silica obtained by air-drying the silica particle dispersion to determine the BET specific surface area of the freeze-dried silica particles obtained by freeze-drying the silica particle dispersion containing the additive aqueous solution (second liquid) containing the mixture. The BET specific surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) obtained by dividing by the BET specific surface area of the particles is 1.3 or more and 10 or less.

One aspect of the method for producing a polishing liquid composition 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, and a silica particle, a basic compound, and an aqueous medium. A step of obtaining a silica particle dispersion liquid by holding the 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, and the silica particle dispersion liquid and the additive. Includes a step of mixing with an aqueous solution.

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

One aspect of the silica particle dispersion liquid of the present invention is a silica particle dispersion liquid containing silica particles, a basic compound, and an aqueous medium, and the light transmittance of the silica particle dispersion liquid at a wavelength of 600 nm is 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 aspect of the silica particle dispersion liquid of the present invention is a silica particle dispersion liquid containing silica particles, a basic compound, and an aqueous medium, which is a freeze-dried silica particle obtained by freeze-drying the silica particle dispersion liquid. BET specific surface area ratio 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 the freeze-dried silica particles / air-dried silica particles). BET specific surface area) is 1.3 or more and 10 or less.

Another aspect of the silica particle dispersion liquid of the present invention is a silica particle dispersion liquid containing silica particles, a basic compound, and an aqueous medium, and the freeze-dried silica particles obtained by freeze-drying the silica particle dispersion liquid. BET specific surface area ratio (B of freeze-dried silica particles) 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.
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 liquid composition for a silicon wafer of the present invention is an additive aqueous solution containing a silica particle dispersion liquid containing silica particles, a basic compound and an aqueous medium, and a water-soluble polymer compound and an aqueous medium. Includes the step of mixing with.

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 liquid 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 the silicon wafer to be polished using a polishing liquid 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 liquid composition kit 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 the silicon wafer to be polished using a polishing liquid composition kit for a silicon wafer.

According to the present invention, a polishing liquid composition for a silicon wafer, a method for producing the same, and the silicon wafer, which can stably reduce the surface roughness (haze) and surface defects (LPD) of the surface of the polished 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 a polishing liquid composition for polishing.

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

Further, according to the present invention, silica particle dispersion used for preparing a polishing liquid composition for a silicon wafer capable of stably reducing the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface. Can provide liquid.

Polishing a silicon wafer to be polished using a polishing liquid composition for a silicon wafer containing silica particles, a basic compound, and a water-soluble polymer compound (hereinafter, may be simply referred to as a "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, suppresses the silica particles causing deterioration of the surface roughness (haze) from coming into direct contact with the silicon wafer to be polished, and prevents the silica particles from coming into direct contact with the silicon wafer to be polished. It acts to suppress corrosion of the wafer surface due to basic compounds that cause deterioration of surface roughness (haze). Therefore, the water-soluble polymer compound contributes to the improvement of the polishing rate, the desorption of particles (silica particles and polishing debris) in the cleaning process of the polished silicon wafer, and the reduction of the surface roughness (haze). There is. Further, the improvement of the desorption of particles contributes to the reduction of surface defects (LPD).

However, even when the polishing liquid composition having the same composition was used, the surface roughness (haze) and the surface defect (LPD) sometimes varied. As a result of exploring the cause of this variation, the present inventor has found that the cause is that excessive adsorption of the water-soluble polymer compound on the silica particles causes the above-mentioned action of the water-soluble polymer compound on the wafer, specifically, water-soluble. It is considered that this is because it hinders the suppression of corrosion on the wafer surface and the improvement of the desorption of particles by the polymer compound. Then, the silica particle dispersion obtained by aging the mixed solution obtained by mixing the silica particles, the basic compound and the aqueous medium for a predetermined time at a predetermined temperature is used for preparing the polishing liquid composition, specifically. Is obtained by mixing silica particles, a basic compound, and an aqueous medium, and holding a mixed solution having a pH of 9 or more and 11 or less at 25 ° C. at 10 ° C. or more and 80 ° C. or less for 1 day or more to obtain water on the surface of the silica particles. By sufficiently stabilizing the sum layer and then mixing the silica particles and the water-soluble polymer compound, excessive adsorption of the water-soluble polymer compound to the silica particles is suppressed, and the water-soluble polymer compound It has been found that the above action on the wafer is sufficiently exhibited. However, these are estimates, 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 liquid and the additive aqueous solution can be immediately used for polishing the silicon wafer to be polished. Also, surface roughness (haze) and surface defects (LPD) can be stably reduced.

Further, when the silica particle dispersion is stored (aged) for a predetermined time under predetermined conditions after the preparation of the silica particle dispersion, the light transmittance is lower than that immediately after the preparation of the silica particle dispersion. From this, the present inventor has found that there is a correlation between the transmittance of the silica particle dispersion and the stability of the hydrated layer of the silica particles. Specifically, when the content of the silica particles in the silica particle dispersion is any of 5% by mass or more and 20% by mass or less, the light transmission rate of the silica particle dispersion at a wavelength of 600 nm is 5.0%. Silica particle dispersion when the pH of the silica particle dispersion at 25 ° C. is 9 or more and 11 or less and the content of silica particles is 10% by mass or more and 15% by mass or less. The transmittance of light with a wavelength of 600 nm is 5.0% or more 3
When it is 0% or less, it is presumed that the hydrated layer of the silica particles is sufficiently stabilized, and if a polishing liquid composition prepared using a silica particle dispersion having such optical characteristics is used, The above-mentioned action of the water-soluble polymer compound on the wafer is fully exhibited, and the surface roughness (haze) and surface defects (LPD) of the silicon wafer surface can be stably reduced (hereinafter, "stability of the present invention"). It is sometimes called "chemical effect".)

Further, it is observed that as the aging period of the silica particle dispersion liquid becomes longer, the surface roughness (haze) and surface defects (LPD) of the silicon wafer surface, particularly the surface defects (LPD), tend to decrease. Further, as the aging period becomes longer, it is observed that the BET specific surface area of the freeze-dried silica particles (hereinafter, also referred to as “lyophilized silica particles”) obtained by freeze-drying the silica particle dispersion liquid tends to increase. .. However, no correlation is found 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 is alkaline hydrolyzed to form reversible pores on the surface of the silica particles, and freeze-drying is performed. It is presumed that the BET specific surface area of the silica particles is increasing. Then, it is obtained by storing it under predetermined conditions for a predetermined time, and is a value obtained by dividing the BET specific surface area of the lyophilized silica particles by the BET specific surface area of the air-dried silica particles. / When a polishing solution composition prepared using a silica particle dispersion having a BET specific surface area of 1.3 or more and 10 or less) of air-dried silica particles is used, the presence of the pores causes silica as a water-soluble polymer compound. Excessive adsorption to the particles is suppressed, or the contact area of the silica particles with respect to the silicon wafer is reduced, and the removability of the silica particles adsorbed on the silicon wafer is improved in the cleaning step of the polished silicon wafer. It is presumed that surface roughness (haze) and surface defects (LPD) can be stably reduced.

In one embodiment, the present invention is a one-component polishing in which a silica particle dispersion containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium are blended. It is a liquid composition. The one-component polishing liquid composition of the present invention is obtained by mixing silica particles, a basic compound, and an aqueous medium as a silica particle dispersion, and a mixed liquid having a pH of 9 or more and 11 or less at 25 ° C. is 10 ° C. or higher. Obtained by holding the compound 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, pH of silica particle dispersion at 25 ° C is 9
When the content of the silica particles is 10% by mass or more and 15% by mass or less, the light transmittance of the silica particle dispersion liquid at a wavelength of 600 nm is 5.0% or more and 30% or less. Or, since the value obtained by dividing the BET specific surface area of the freeze-dried silica particles by the BET specific surface area of the air-dried silica particles is 1.3 or more and 10 or less, the composition of the conventional one-component polishing liquid is used. It is possible to overcome the problem of the polishing liquid composition that the polishing performance is unstable when the polishing liquid composition is used for polishing immediately after the preparation of the polishing liquid composition, and the polishing liquid composition is the one immediately after the preparation. Even if there is, the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface can be reduced.

Further, in another aspect, the present invention comprises a silica particle dispersion liquid (first liquid) containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium (first solution). The two liquids) are stored in a state where they are not 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 light transmittance of 5.0% or more and 30% or less at a wavelength of 600 nm when the content of silica particles is any one of 5% by mass or more and 20% by mass or less. When 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 or less, the wavelength of the silica particle dispersion liquid is 600 nm. The light transmittance is 5.0% or more and 30% or less, or the value obtained by dividing the BET specific surface area of the freeze-dried silica particles by the BET specific surface area of the air-dried silica particles is 1.3 or more and 10 or less. is there. As the silica particle dispersion, 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 is held at 10 ° C. or more and 80 ° C. or less for 1 day or more. Can be obtained by

In the present invention, "the light transmittance of the silica particle dispersion liquid at a wavelength of 600 nm is 5.0% or more and 30% or more when the content of the silica particles is 5% by mass or more and 20% by mass or less. % Or less ”, but this is the silica particle dispersion used in the preparation of the one-component polishing liquid composition of the present invention, and the polishing liquid composition kit for silicon wafers of the present invention (hereinafter referred to as). The content of silica particles in the silica particle dispersion liquid (first liquid) constituting the "kit for preparing a polishing liquid composition" is not necessarily 5% by mass or more and 20% by mass or less. It is not specified, for example, the content ratio of the silica particles to the basic compound in the silica particle dispersion having a concentration of 5% by mass or more and 20% by mass or less of the silica particles, and the content thereof. Silica particle dispersions having the same mass ratio are also included in the silica particle dispersions. 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, and the transmittance is obtained. Can be done.

Further, in the present invention, "the transmittance of light at a wavelength of 600 nm of the silica particle dispersion is 9 or more and 11 or less at 25 ° C. of the silica particle dispersion, and the content of the silica particles is 10% by mass or more and 15 or less. In any case of mass% or less, it is 5.0% or more and 30% or less. "
However, this is the silica particle dispersion used for preparing 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 specify 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 a silica particle dispersion having a pH of 9 or more and 11 or less, preferably 10 ± 0.3, and a silica particle content of 10% by mass or more and 15% by mass or less, preferably 10% by mass, at 25 ° C. A silica particle dispersion having the same content ratio between the silica particles and the basic compound and the content ratio is also included in the silica particle dispersion. That is, the pH of the silica particle dispersion and the content of the silica particles can be clarified to make it easier to obtain the transmittance.

However, the transmittance of light at 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. When it is 5% by mass or more and 15% by mass or less, it is one of the preferable aspects of the polishing liquid 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) and as a silica particle dispersion liquid. 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 when the content of silica particles is 5% by mass or more and 20% by mass or less, the wavelength is 600 nm. The light transmittance 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 silica particles is 10% by mass or more and 15% by mass or less. When, the light transmittance of the silica particle dispersion liquid having a wavelength of 600 nm is 5.0.
% Or more and 30% or less, or the value obtained by dividing the BET specific surface area of the lyophilized silica particles by the BET specific surface area of the air-dried silica particles is 1.3 or more and 10 or less. It is possible to overcome the problem of the liquid type polishing liquid composition, that the polishing performance is unstable when the polishing liquid composition obtained by mixing the two liquids is immediately used for polishing, and the polishing liquid of the present invention can be overcome. Even if 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 can be reduced. You can.

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, so that the silica particle dispersion liquid (first liquid) is stored separately. By adjusting the amount of the additive aqueous solution (second liquid) used when mixing the additive aqueous solution (second liquid) with the additive aqueous solution (first liquid), the silica particle dispersion liquid (first liquid) and the additive aqueous solution (second liquid) are used. The concentration of the water-soluble polymer compound and the like in the polishing liquid composition obtained by mixing with the liquid) can be adjusted, and various polishing liquid compositions can be prepared.

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, but colloidal silica is more preferable from the viewpoint of improving the surface smoothness of the silicon wafer.

As the usage form of the silica particles (component A), a slurry is preferable from the viewpoint of operability. When the silica particles are colloidal silica, the colloidal silica is preferably obtained from a hydrolyzate of alkoxysilane from the viewpoint of preventing contamination of the silicon wafer by alkali metal, alkaline earth metal, or the like. Silica particles obtained from a 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 is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 15 nm from the viewpoint of ensuring the polishing rate. Above, even more preferably, it is 20 nm or more. Further, from the viewpoint of ensuring a polishing rate and reducing surface defects (LPD), the thickness 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 size is preferably 5 nm or more, more preferably 5 nm or more, from the viewpoint of ensuring 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 size 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, and preferably 2.3 or less, from the viewpoint of ensuring the polishing rate and reducing the surface defects of the silicon wafer. 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 and so-called eyebrows. When the silica particles are colloidal silica, the degree of association is preferably 3.0 or less, more preferably 2.5 or less, still more preferably 2.3 or less, from the viewpoint of ensuring the polishing rate and reducing surface defects. Yes, 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 size is a value measured by a dynamic light scattering method, and can be measured using, for example, the apparatus described in the examples.
Association = average secondary particle size / average primary particle size

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

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, and further, from the viewpoint of reducing surface defects (LPD) of the silicon wafer. 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 elevation analysis (ICP) or atomic absorption spectrometry.

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, still more preferably 5% by mass or more, from the viewpoint of economic efficiency such as reduction of production and transportation costs. Is 8% by mass or more. The content of silica particles in the silica particle dispersion is preferably 25% by mass or less, more preferably 20% by mass or less, still more 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 speed.
It is 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 described later.

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

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

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

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

The water-soluble basic compound (component B) is at least one nitrogen-containing basic compound selected from an amine compound and an ammonium compound. 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 concentration range of the present invention, but here, "water-soluble" means water ("water-soluble". It means having a solubility of 0.5 g / 100 ml or more with respect to (20 ° C.), preferably 2 g / 100 ml or more, and the "water-soluble basic compound" means when dissolved in water. , Refers to a compound showing basicity.

Examples of the nitrogen-containing basic compound selected from the amine compound and the ammonium compound include ammonia, ammonium hydroxide, ammonium carbonate, ammonium hydrogencarbonate, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, and triethylamine. Monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N-methyl-N, N-dietanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, N, N-dibutylethanol Amine, N- (β-aminoethyl) ethaneolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, ethylenediamine, hexamethylenediamine, piperazine / hexahydrate, piperazine anhydride, 1- (2-aminoethyl) Examples include piperazine, N-methylpiperazin, diethylenetriamine, and tetramethylammonium hydroxide. Two or more of these nitrogen-containing basic compounds may be mixed and used. Nitrogen-containing basic compounds contained in the silica particle dispersion include reduction of surface roughness (haze) and surface defects (LPD) of the silicon wafer, improvement of storage stability of the silica particle dispersion, and ensuring polishing rate. Ammonia is more preferable from the viewpoint of.

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% by mass or more. The content of the basic compound in the silica particle dispersion is preferably 5% by mass or less, more preferably 4% by mass or less, still more 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 the silica particles, it is preferably 500 or less, more preferably 200 or less, and further preferably 100 or less.

[Aqueous medium]
Examples of the aqueous medium contained in the silica particle dispersion include water such as ion-exchanged water and ultrapure water, a mixed medium of water and a solvent, and the like, and examples of the solvent include a solvent that can be mixed with water (for example, a solvent that can be mixed with water (for example). (Alcohol such as ethanol) is preferable. As the water-based medium, ion-exchanged water or ultrapure water is more preferable, and ultrapure water is even more preferable, from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. 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 as long as the effects of the present invention are not impaired, but from the viewpoint of economic efficiency, it is not particularly limited. 95% by mass or more is preferable, 98% by mass or more is more preferable, and substantially 100% by mass is further preferable.

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

As for the measurement conditions of the silica particle dispersion liquid to be measured for the transmittance of light having a wavelength of 600 nm, the content of the silica particles is 10 mass and the temperature of the silica particle dispersion liquid is 25 ° C. from the viewpoint of avoiding uncertainty. The pH in is 9 or more and 11 or less. The pH is preferably 10 ± 0.3.

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

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

Examples of the water-soluble polymer compound (component C) contained in the additive aqueous solution include polyamides, cellulose derivatives, polyvinyl alcohol-based polymers, and water-soluble polymer compounds containing structural units derived from acrylamide derivatives. 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 the polyvinyl alcohol-based polymer include polyvinyl alcohol (PVA), alkylene oxide-modified PVA, cation-modified PVA, anion-modified PVA, and alkyl-modified PVA. Examples of the water-soluble polymer compound containing a structural unit derived from an acrylamide derivative include a water-soluble polymer compound containing 75% by mass or more of the structural unit I represented by the following general formula (1). However, in the following general formula (1), R ¹ is a hydroxyalkyl group having 1 to 2 carbon atoms. The monomer that is the 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). It can be used alone or in combination of two or more. Among these monomers, HEAA is preferable from the viewpoint of reducing the surface defects (LPD) and surface roughness (haze) of the silicon wafer.

Regarding a water-soluble polymer compound containing a structural unit derived from an acrylamide derivative, "containing 75% by mass or more of the structural unit I" means that the mass of the structural unit I in one molecule of the water-soluble polymer compound is water-soluble. It means that it is 75% or more of the weight average molecular weight (Mw) of the polymer compound. Further, 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 determined to be a reaction in all the steps of synthesizing the water-soluble polymer compound depending on the synthesis conditions. A value calculated from the amount of the compound (mass%) for introducing the structural unit I charged in the reaction tank may be used, which is occupied in the compound for introducing all the structural units charged in the tank. ..

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

The water-soluble polymer compound containing a structural unit derived from an acrylamide derivative may contain a structural unit other than the structural unit I as long as the effects of the present invention are exhibited. When a structural unit other than the structural unit I (also referred to as “constituent unit II”) is included, the structural unit other than the structural 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). Constituent 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 represented by the general formula (1) and the structural unit II, the structural unit in the copolymer of the structural unit I and the structural unit II The array can 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. Polymers, HEAA and AA copolymers, HEAA and MAA copolymers, HEAA and VP copolymers, HEAA and DMAA copolymers, HEAA and DEAA copolymers, HMAA and AA co-polymers. A homopolymer or co-polymer containing a structural unit derived from an acrylamide derivative such as a polymer, a copolymer of HMAA and MAA, a copolymer of HMAA and VP, a copolymer of HMAA and DMAA, and a copolymer of HMAA and DEAA. Polymers may be mentioned, and these may be used alone or in combination of two or more, but from the viewpoint of reducing surface defects of silicon wafers, HEAA homopolymers, HMAA homopolymers, and homopolymers of HEAA and HMAA. , HEAA and NIPAM copolymer, HMAA and NIPAM copolymer, and at least one polymer selected from the group consisting of HEAA and HMAA and NIPAM copolymers are preferable. At least one polymer selected from the group consisting of a coalescence and a copolymer of HEAA and HMAA is more preferable, and a HEAA homopolymer is further preferable.

Two or more of these water-soluble polymer compounds may be mixed and used at an arbitrary ratio. Among these water-soluble polymer compounds, polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, polyethylene glycol, HEAA homopolymer, and HEAA homopolymer, 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 a copolymer of NIPAM and acrylamide (AAm) is preferable, and a group consisting of polyvinyl alcohol, hydroxyethyl cellulose, HEAA homopolymer, and a copolymer of NIPAM and AAm. 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, still more preferably 20,000 or more, from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. From the viewpoint of suppressing aggregation of silica particles, the amount 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 described later.

The weight average molecular weight of polyvinylpyrrolidone is preferably 10,000 or more, more preferably 30,000 or more, still more preferably 200,000 or more, from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. From the viewpoint of suppressing aggregation of silica particles, the amount is preferably 1 million or less, more preferably 700,000 or less, still more 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, still more preferably 240,000 or more, from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. From the viewpoint of suppressing aggregation of silica particles, the amount 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, still more preferably 200,000 or more, from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. , Even more preferably 300,000 or more, even more preferably 40.
It is 10,000 or more, and from the viewpoint of suppressing 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, still 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, still more preferably 100,000 or more, from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. It is 200,000 or more, more preferably 300,000 or more, and from the viewpoint of suppressing aggregation of silica particles, it is preferably 1 million or less, more preferably 800,000 or less, still more preferably 600,000 or less. The weight average molecular weight of the copolymer of NIPAM and AAm is measured by the method described in Examples described later.

The content of the water-soluble polymer compound (component C) contained in the additive aqueous solution is preferably 0.5% by mass or more, more preferably 1% by mass, from the viewpoint of economic efficiency such as reduction of production and transportation costs. As mentioned above, it 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.

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

The pH of a mixed solution (polishing solution composition) used for polishing a silicon wafer to be polished and obtained by mixing a silica particle dispersion liquid constituting a polishing solution composition and an aqueous additive solution and a diluted solution thereof at 25 ° C. From the viewpoint of reducing the surface roughness (haze), it is preferably 8 or more, more preferably 9 or more, further preferably 10 or more, preferably 13 or less, more preferably 12 or less, still more preferably 11 or less. .. The pH can be adjusted by appropriately adding a pH adjusting agent (for example, ammonia). Here, the pH at 25 ° C. can be measured using a pH meter (for example, Toa Denpa Kogyo Co., Ltd., HM-30G), and is a value 1 minute after the electrode is immersed in the polishing liquid 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 suppresses corrosion of the wafer surface due to the basic compound and imparts wettability to the wafer surface, thereby causing particles to adhere to the wafer surface, which is considered to be caused by drying of the wafer surface. It acts to suppress. Further, in the cleaning process of 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, in combination with the water-soluble polymer compound, enhances the reduction of surface roughness (haze) and surface defects (LPD).

The polyoxyalkylene compound (component D) is a polyhydric alcohol alkylene oxide adduct, and is a polyhydric alcohol derivative obtained by addition polymerization of an alkylene oxide such as ethylene oxide or propylene oxide to the 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), determines the surface defects (LPD) and surface roughness of the silicon wafer from the viewpoint of increasing the adsorption strength of the polyoxyalkylene compound on the surface of the silicon wafer. From the viewpoint of reducing haze, the number is preferably 2 or more, and from the viewpoint of ensuring the polishing speed, 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. Of these, ethylene glycol alkylene oxide adducts are preferred.

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 surfaces of silicon wafers. From the viewpoint of reducing roughness (haze), the alkyleneoxy group contained in the polyoxyalkylene compound is preferably composed of at least one alkyleneoxy group selected from the group consisting of EO and PO, and more preferably composed of EO. If the polyoxyalkylene compound contains both EO and PO, the sequence of EO and PO may be block or random.

The weight average molecular weight of the polyoxyalkylene compound (component D) is preferably 500 or more, from the viewpoint of increasing the amount of the polyoxyalkylene compound adsorbed on 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 250,000 or less, from the viewpoint of increasing the amount of the polyoxyalkylene compound adsorbed on 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>
Equipment: HLC-8320 GPC (Tosoh Corporation, integrated detector)
Column: GMPWXL + GMPWXL (anion)
Eluent: 0.2M phosphate buffer / CH ₃ CN = 9/1
Flow rate: 0.5 ml / min
Column temperature: 40 ° C
Detector: RI Detector Standard Material: Monodisperse Polyethylene Glycol with Known Molecular Weight

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

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

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

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

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

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

<Nonionic surfactant>
Nonionic surfactants include polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbit fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and poly. 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 the method for preparing the polishing liquid composition will be described.

[Preparation method of silica particle dispersion]
The silica particle dispersion liquid is obtained by undergoing an aging step of holding a mixed liquid obtained by mixing silica particles (component A), a basic compound (component B) and an aqueous medium 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 by 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 agglutination of silica particles are contained in an aqueous medium, it is preferable to remove the coarse particles by centrifugation, filtration using a filter, or the like.

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, preferably 60 ° C. or lower, from the viewpoint of storage stability. The predetermined time is 1 day (1 day (24 hours) ± 6 hours) or more, preferably 3 days (3 days), from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. (72 hours) ± 6 hours) or more, more preferably 5 days (5 days (120 hours) ± 6 hours) or more, and from the viewpoint of improving productivity, preferably 30 days (30 days (720 hours) ± 6). 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, still more preferably, from the viewpoint of reducing surface defects (LPD) and surface roughness (haze) of the silicon wafer. 28 days (28 days (672 hours) ± 6 hours) or more, more preferably 40 days (40 days (960 hours) ± 6 hours) or more, still more preferably 60 days (60 days (1440 hours) ± 6 hours) or more More preferably, it is 80 days (80 days (1920 hours) ± 6 hours) or more. 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, still more preferably 12 days (12 days (288 hours) ± 6 hours) or more, even more It is preferably 28 days (28 days (672 hours) ± 6 hours) or more, more preferably 40 days (40 days (960 hours) ± 6 hours) or more, and even 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 a time that has elapsed from the time when the constituent components of the silica particle dispersion have been mixed and before the start of mixing with the additive aqueous solution. Therefore, the "predetermined time" includes not only the time stored in the warehouse or the like but also the transportation time when the transportation or the like is performed. In the present application, the predetermined time represented by the number of days means the number of days × 24 hours ± 6 hours. For example, the predetermined time "1 day" means 24 hours ± 6 hours.

Aging of a mixed solution obtained by mixing silica particles (component A), a basic compound (component B) and an aqueous medium is possible from the viewpoint of reducing surface defects (LPD) and surface roughness (haze). It is preferable that the container is filled with air and light so as not to enter.

[Preparation method of aqueous additive solution]
The additive aqueous solution can be prepared by blending a water-soluble polymer compound (component C), an aqueous medium, and if necessary, an arbitrary component.

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

<Method of polishing silicon wafer to be polished, method of manufacturing semiconductor substrate>
One aspect of the method for polishing a silicon wafer to be polished of the present invention (hereinafter, also referred to as "the polishing method of the present invention") and the method for manufacturing a semiconductor substrate of the present invention (hereinafter, referred to as "the manufacturing method of the present invention"). In one aspect, the silicon wafer to be polished is polished by using the polishing liquid composition of the present invention as it is or by using a polishing liquid composition obtained by diluting the polishing liquid 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 manufacturing method of the present invention, the silica particle dispersion liquid (first liquid) and the additive aqueous solution (first liquid) constituting the polishing liquid composition preparation kit of the present invention are used. After mixing with the second liquid), dilute with an aqueous medium if necessary, or if necessary, either one of the silica particle dispersion liquid (first liquid) and the additive aqueous solution (second liquid) or It includes a step of polishing a silicon wafer to be polished using a polishing liquid composition obtained by diluting both with an aqueous medium and then mixing them. The amounts of the silica particle dispersion liquid and the additive aqueous solution 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-component polishing liquid composition obtained by mixing silica particles, a basic compound, a water-soluble polymer compound, and an aqueous medium has a predetermined storage time and a predetermined temperature after mixing the components. If it is used for polishing directly without going through the aging process of holding it in, surface defects (LPD) and surface roughness (haze) are deteriorated. In the polishing method of the present invention and the production method of the present invention, the specific surface area of the silica particle dispersion containing silica particles whose 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. An abrasive solution composition prepared using a silica particle dispersion having a value of 1.3 or more and 10 or less (including an abrasive solution composition prepared using the polishing solution composition preparation kit of the present invention). Since it is used for polishing the silicon wafer to be polished, surface defects (LPD) and surface roughness (haze) can be reduced even if these are used for polishing the silicon wafer to be polished immediately after the polishing liquid composition is prepared.

The step of polishing the silicon wafer to be polished includes a wrapping (coarse polishing) step of flattening the silicon wafer obtained by slicing a silicon single crystal ingot into a thin disk shape, and an etching of the wrapped silicon wafer. After that, there is a finish polishing step of mirroring the surface of the silicon wafer. The polishing liquid composition of the present invention is more preferably used in the above-mentioned finish polishing step.

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

The polishing pressure refers to the pressure of the surface plate applied to the surface to be polished of the silicon wafer to be polished 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 production method of the present invention and the polishing method of the present invention further include a step of polishing the polished silicon wafer using the polishing liquid composition, and then a step of cleaning the polished silicon wafer to be polished.

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 liquid composition kit for a silicon wafer. Here, "using the polishing liquid composition kit for silicon wafer" means that the silica particle dispersion liquid (first liquid) and the additive aqueous solution (second liquid) of the above-mentioned "polishing liquid composition kit for silicon wafer" are used. After mixing, dilute with an aqueous medium if necessary, or if necessary, dilute either or both of the silica particle dispersion (first solution) and the additive aqueous solution (second solution) with an aqueous medium. Then, the polishing liquid composition obtained by mixing these is used.

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

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 containing silica particles, a basic compound and an aqueous medium, and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. There,
The transmittance of light having a wavelength of 600 nm of the silica particle dispersion is 5.0% or more, more preferably 5 in any case where 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. Abrasive liquid composition for wafers.
<2> The polishing liquid composition for a silicon wafer according to <1>, wherein the pH of the silica particle dispersion liquid at 25 ° C. is 9 or more and 11 or less.
<3> 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 aqueous additive 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 9 or more and 11 or less, preferably pH 10 ± 0.3, at 25 ° C. of the silica particle dispersion, and the content of the silica particles is 10% by mass. When it is 15% by mass or less, preferably 10% by mass, 5.
0% or more, more preferably 5% or more, still more preferably 8.0% or more, even more preferably 8% or more, even 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 aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. There,
The transmittance of light at 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 A polishing liquid composition for a silicon wafer, 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 aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. There,
BET ratio obtained by dividing the BET specific surface area of the freeze-dried silica particles obtained by freeze-drying the silica particle dispersion by the BET specific surface area of the air-dried silica particles obtained by air-drying the silica particle dispersion. The surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) is 1.3 or more, preferably 1.5 or more, more preferably 2.0 or more, and 10 or less, preferably 5. A polishing liquid composition for a silicon wafer, which is 0.0 or less, more preferably 3.0 or less.
<6> The amount of silanol groups per unit mass of the lyophilized 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. , Preferably 10 mmol / g or less, more preferably 5.0 mmo
The polishing liquid composition for a silicon wafer according to <5>, which is l / g or less, more preferably 3.0 mmol / g or less.
<7> The porosity of the surface of the silica particles after freeze-drying is preferably 1.5% or more, more preferably 4.0% or more, still more preferably 6.0% or more, and preferably 30% or less. The polishing liquid composition for a silicon wafer according to <5> or <6>, which is more preferably 20% or less, still more preferably 15% or less.
<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 copolymer of NIPAM and AAm. Includes species of water-soluble polymeric compounds, more preferably at least one water-soluble polymeric compound selected from the group consisting of polyvinyl alcohol, hydroxyethyl cellulose, HEAA homopolymers, and copolymers of NIPAM and AAm. 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, still more preferably 20,000 or more, preferably 150,000 or less, more preferably 100,000 or less, and further. The polishing liquid composition for a silicon wafer according to <9>, 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, still more preferably 200,000 or more, preferably 1 million or less, more preferably 700,000 or less, still more 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, still more 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, still more preferably 200,000 or more, still more preferably 300,000 or more, still more preferably 400,000 or more. The silicon wafer according to <9> above, preferably 2 million or less, more preferably 1.5 million or less, still more preferably 1 million or less, even more preferably 900,000 or less, still more preferably 800,000 or less. Abrasive liquid composition for.
<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, and preferably 100. The polishing liquid composition for a silicon wafer according to <9> above, which is 10,000 or less, more preferably 800,000 or less, still more preferably 600,000 or less.
<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, still more preferably 15 nm or more, still more preferably 20 nm or more, preferably 50 nm or less, more preferably 45 nm or less. The polishing liquid composition for a 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 the water-soluble polymer compound / mass of silica particles) is preferably 0.005 or more, more preferably 0.005 or more. 0.0075 or more, still more preferably 0.009 or more, even more preferably 0.015 or more, preferably 1.0 or less, more preferably 0.8 or less, still more preferably 0.6 or less, even more preferably. The polishing liquid composition for a silicon wafer according to any one of <1> to <16>, wherein is 0.4 or less, more preferably 0.3 or less.
<18> The pH of the polishing liquid composition at 25 ° C. 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 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 aqueous additive solution (second liquid) containing a water-soluble polymer compound and an aqueous medium are contained.
The light transmittance of the silica particle dispersion liquid (first liquid) at a wavelength of 600 nm is more preferably 5.0% or more in any case where the content of the silica particles is 5% 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, and 30% or less, preferably 24% or less, more preferably 16% or less. , Abrasive liquid composition kit for silicon wafers.
<20> The polishing liquid composition kit for a silicon wafer according to <19>, wherein the pH of the silica particle dispersion liquid at 25 ° C. is 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 aqueous additive solution (second liquid) containing a water-soluble polymer compound and an aqueous medium are contained.
The light transmittance of the silica particle dispersion liquid (first liquid) at a wavelength of 600 nm is such that the pH of the silica particle dispersion liquid at 25 ° C. is 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, still more preferably 8.0% or more, still more preferably 8% or more. A polishing liquid composition kit for silicon wafers, further preferably 11% or more, 30% or less, preferably 24% or less, and even 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 aqueous additive solution (second liquid) containing a water-soluble polymer compound and an aqueous medium are contained.
BET ratio obtained by dividing the BET specific surface area of the freeze-dried silica particles obtained by freeze-drying the silica particle dispersion by the BET specific surface area of the air-dried silica particles obtained by air-drying the silica particle dispersion. The surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) is 1.3 or more, preferably 1.5 or more, more preferably 2.0 or more, and 10 or less, preferably 5. A polishing liquid composition kit for a silicon wafer, which is 0.0 or less, more preferably 3.0 or less.
<23> The amount of silanol groups per unit mass of the lyophilized 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 is preferable. The polishing liquid composition kit for a silicon wafer according to <22>, wherein is 10 mmol / g or less, more preferably 5.0 mmol / g or less, still more preferably 3.0 mmol / g or less.
<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, and more. The polishing liquid composition kit for a silicon wafer according to <22> or <23>, preferably 20% or less, more preferably 15% or less.
<25> The BET specific surface area of the freeze-dried silica particles 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 g or less.
<26> The water-soluble polymer compound is preferably selected from the group consisting of polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, polyethylene glycol, polyoxyethylene, HEAA homopolymer, and a copolymer of NIPAM and AAm. It contains one water-soluble polymer compound, more preferably at least one water-soluble polymer compound selected from the group consisting of polyvinyl alcohol, hydroxyethyl cellulose, HEAA homopolymers and 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, still more preferably 20,000 or more, preferably 150,000 or less, more preferably 100,000 or less, and further. The polishing liquid composition kit for a silicon wafer according to <26>, preferably 80,000 or less.
<28> The weight average molecular weight of the polyvinylpyrrolidone is preferably 10,000 or more, more preferably 30,000 or more, still more preferably 200,000 or more, preferably 1 million or less, more preferably 700,000 or less, still more 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, still more 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. The silicon wafer according to <26> above, preferably 2 million or less, more preferably 1.5 million or less, still more preferably 1 million or less, even more preferably 900,000 or less, still more preferably 800,000 or less. Abrasive liquid composition kit for.
<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, and preferably 100. The polishing liquid composition kit for a silicon wafer according to <26> above, which is 10,000 or less, more preferably 800,000 or less, still more 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, still more 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, still more 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, still more preferably 0.5% by mass. The polishing liquid composition for a silicon wafer according to any one of <19> to <33> above, preferably 5% by mass or less, more preferably 4% by mass or less, still more preferably 3% by mass or less. kit.
<35> The mass ratio of the silica particles to the basic compound (silica particles / basic compound) contained in the silica particle dispersion is preferably 0.6 or more, more preferably 1 or more, and further preferably 3 or more. The polishing liquid composition kit for a silicon wafer according to any one of <19> to <34> above, 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, still more preferably 1.5% by mass or more, and is preferable. The polishing liquid composition kit for a silicon wafer according to any one of <19> to <35>, wherein is 20% by mass or less, more preferably 15% by mass or less, still more preferably 12% by mass or less.
<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.
A step of mixing the water-soluble polymer compound and the aqueous medium to obtain an aqueous additive solution, and
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 higher, preferably 30 ° C. or higher, 80 ° C. or lower, 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, and
A method for producing a polishing liquid composition for a silicon wafer, which comprises a step of mixing the silica particle dispersion liquid 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, still more preferably 8% by mass or more, and preferably 25% by mass or less. The method for producing a polishing liquid composition for a silicon wafer according to <37>, wherein the amount is more preferably 20% by mass or less, still more preferably 15% by mass or less.
<39> The method for manufacturing a polishing liquid composition kit for a silicon wafer according to any one of <19> to <36>.
A step of mixing a water-soluble polymer compound and an aqueous medium to obtain an aqueous additive solution,
A mixed solution having a pH of 9 or more and 11 or less at 25 ° C. obtained by mixing silica particles, a basic compound and an aqueous medium is 10 ° C. or higher, preferably 30 ° C. or higher, 80 ° C. or lower, preferably 60 ° C. or lower. 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, It includes a step of obtaining a silica particle dispersion liquid by holding it for preferably 30 days (30 days (720 hours) ± 6 hours) or less, more preferably 8 days (8 days (192 hours) ± 6 hours) or less. A method for manufacturing a polishing liquid 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, still more preferably 8% by mass or more, and preferably 25% by mass or less. The method for producing a polishing liquid composition kit for a silicon wafer according to <39>, wherein the amount is more preferably 20% by mass or less, still more preferably 15% by mass or less.
<41> 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 5.0% or more, more preferably 5 in any case where 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 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 9 or more and 11 or less, preferably pH 10 ± 0.3, at 25 ° C. of the silica particle dispersion, and the content of the silica particles is 10% by mass. When it is 15% by mass or less, preferably 10% by mass, 5.
0% or more, more preferably 5% or more, still more preferably 8.0% or more, even more preferably 8% or more, even more preferably 11% or more, 30% or less, preferably 24% or less, more preferably. Is 16% or less, a silica particle dispersion.
<43> A silica particle dispersion containing silica particles, a basic compound, and an aqueous medium.
BET ratio obtained by dividing the BET specific surface area of the freeze-dried silica particles obtained by freeze-drying the silica particle dispersion by the BET specific surface area of the air-dried silica particles obtained by air-drying the silica particle dispersion. The surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) is 1.3 or more, preferably 1.5 or more, more preferably 2.0 or more, and 10 or less, preferably 5. A silica particle dispersion which is 0.0 or less, more preferably 3.0 or less.
<44> A polishing liquid for a silicon wafer, which comprises a step of mixing the silica particle dispersion liquid according to any one of <41> to <43> and an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. Method for producing composition.
<45> A method for manufacturing a semiconductor substrate, which comprises a step of polishing a silicon wafer to be polished using the polishing liquid composition for a silicon wafer according to any one of <1> to <18>.
<46> A method for polishing a silicon wafer to be polished, which comprises a step of polishing the silicon wafer to be polished using the polishing liquid composition for a silicon wafer according to any one of <1> to <18>.
<47> A method for manufacturing a semiconductor substrate, which comprises a step of polishing a silicon wafer to be polished using the polishing liquid 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, which comprises a step of polishing the silicon wafer to be polished using the polishing liquid composition kit for a silicon wafer according to any one of <19> to <36>.

1. 1. Synthesis of water-soluble polymer compound or details thereof (1) Synthesis of HEAA homopolymer (pHEAA) The HEAA homopolymer used for preparing the polishing liquid compositions of Examples 1 to 22 and Comparative Examples 1 and 2 below is It was synthesized as follows.

Hydroxyethyl acrylamide (150 g) (1.30 mol, manufactured by Kohjin) was dissolved in 100 g of ion-exchanged water to prepare an aqueous monomer solution. Separately, 70 g of 2,2'-azobis (2-methylpropion amidine) dihydrochloride (polymerization initiator, V-50 1.30 mmol manufactured by Wako Pure Chemical Industries, Ltd.)
Was dissolved in ion-exchanged water to prepare an aqueous polymerization initiator solution. After putting 1180 g of ion-exchanged water into a 2 L separable flask equipped with a Dimroth condenser, a thermometer and a crescent-shaped Teflon (registered trademark) stirring blade, the inside of the separable flask was replaced with nitrogen. Next, after raising the temperature in the separable flask to 68 ° C. using an oil bath, the above-mentioned monomer aqueous solution and the above-mentioned polymerization initiator aqueous solution prepared in advance are each stirred for 3.5 hours in the separable flask. Dropped. After completion of the dropwise addition, the temperature and stirring of the reaction solution were maintained for 4 hours to obtain 1500 g of a colorless and transparent 10% by mass polyhydroxyethylacrylamide (HEAA homopolymer (weight average molecular weight: 720,000) 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 Kasei Kogyo Co., Ltd.) was used as the polymer compound, and polyvinyl alcohol (PVA, weight average) was used as the water-soluble polymer compound in Example 26 and Comparative Example 6. A PVA105) manufactured by Kuraray Co., Ltd. having a molecular weight of 25,000 was used.

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

40 g of isopropylacrylamide (0.35 mol manufactured by Kojin), 10 g of acrylamide (0.14 mol manufactured by Wako Pure Chemical Industries, Ltd.) and ion-exchanged water in a 500 ml separable flask equipped with a thermometer and a 5 cm crescent-shaped Teflon (registered trademark) stirring blade. 75 g and 0.028 g of 30% hydrogen peroxide (manufactured by 0.25 mmol 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 at 50 ml / min. For 30 minutes. On the other hand, 0.043 g of L-ascorbic acid (polymerization initiator, manufactured by 0.25 mmol Wako Pure Chemical Industries, Ltd.) 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 dissolve L-ascorbic acid. An acid solution was obtained and nitrogen was blown into it at 50 ml / min. For 30 minutes. Next, a nitrogen-blown L-ascorbic acid solution was added dropwise at 25 ° C. over 30 minutes to a solution containing isopropylacrylamide and acrylamide in a 500 ml separable flask, and then at 25 ° C., 200 rpm (peripheral speed 1.05 m / s).
) Was stirred for 1 hour. Further, 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, drop it into 4 L of acetone (manufactured by Wako Pure Chemical Industries, Ltd.) and NIP.
A copolymer (solid) of NIPAM and AAm having a weight ratio of AM and 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 translucent solid (copolymer of NIPAM and AAm (weight average molecular weight 400,000, yield 85%).

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

<Measurement of water solubility>
The water solubility of each water-soluble polymer compound was adjusted by adjusting 0.5 g / 100 ml of a water-soluble polymer compound aqueous solution, and the state was visually confirmed according to the following evaluation method.
(Evaluation methods)
(1) Pour about 90 ml of water into the screw tube and start stirring at room temperature.
(2) Weigh 0.5 g of the water-soluble polymer compound into the screw tube and put it in.
(3) After stirring at room temperature for 3 hours, the temperature is raised to 70 ° C. and the mixture is further stirred for 3 hours.
(4) After cooling to room temperature, add water to make 100 ml.
(5) Visually check the condition of the aqueous solution. If it is transparent, it is a water-soluble compound.
All of 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 size of abrasive (silica particles)>
The average primary particle diameter (nm) of the abrasive was calculated by the following formula using the ^{specific surface area S (m 2 / g) calculated by the BET (nitrogen adsorption) method.}
Average primary particle size (nm) = 2727 / S

For the specific surface area of the abrasive material, after performing the following [pretreatment], about 0.1 g of the measurement sample is concentrated in the measurement cell to 4 digits after the decimal point, and immediately before the measurement of the specific surface area, 30 minutes in an atmosphere of 110 ° C. After drying, it was measured by the 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 whose pH has been adjusted to 2.5 ± 0.1 is taken 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 crushed in an agate mortar.
(D) The pulverized sample is suspended in ion-exchanged water at 40 ° C. and filtered through a membrane filter having a pore size of 1 μm.
(E) The filtrate on the filter is washed 5 times with 20 g of ion-exchanged water (40 ° C.).
(F) Take the filter to which the filter material is attached in a petri dish and dry it in an atmosphere of 110 ° C. for 4 hours.
(G) A dried filter (abrasive grains) was taken so as not to be mixed with filter waste, and finely pulverized in a mortar to obtain a measurement sample.

<Average secondary particle size of abrasive (silica particles)>
The average secondary particle size (nm) of the abrasive is such that the abrasive is added to ion-exchanged water so that the concentration of the abrasive is 0.25% by mass, and then the obtained aqueous dispersion is used as Disposable Sizein.
g Cuvette (10 mm cell made of polystyrene) was placed 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 pre-frozen at a freezing temperature of -45 ° C for 8 hours using a freeze-dryer (DFR-5N-B, manufactured by UVLAC Co., Ltd.), followed by a freezing temperature of -45 ° C and a drying pressure of 10 Pa. Then, it was freeze-dried for 48 hours. The obtained freeze-dried product was finely pulverized using an agate mortar to obtain a measurement sample. Approximately 0.1 g of the obtained measurement sample is concentrated in a measurement cell to 4 digits after the decimal point, dried for 30 minutes in an atmosphere of 110 ° C. immediately before the measurement of the specific surface area, and then the specific surface area measuring device (micromeric automatic). Using the specific surface area measuring device Flowsorb III2305, manufactured by Shimadzu Corporation, the specific surface area (m ² / g) of the lyophilized silica particles was measured by the nitrogen adsorption method (BE).
It was measured by the T method).

<Measurement of BET specific surface area of air-dried silica particles>
The silica particle dispersion was air-dried for 48 hours at room temperature (25 ° C.). The obtained dried product was finely pulverized using an agate mortar to obtain a measurement sample. Approximately 0.1 g of the obtained measurement sample is concentrated in a measurement cell to 4 digits after the decimal point, dried in an atmosphere of 110 ° C. for 30 minutes immediately before the measurement of the specific surface area, and then the specific surface area measuring device (micromeric automatic). Using the 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 amount>
The amount of silanol groups per unit mass of the lyophilized silica particles was measured using a differential differential thermal balance (TG-DTA) (manufactured by Rigaku Denki Kogyo Co., Ltd., trade name: Thermo Plus TG8120). The lyophilized silica particles were heated to 25-700 ° C. at a rate of 10 ° C./min under airflow (300 mL / min), and the mass residue measured at 200 ° C. was the weight (g) _{of SiO 2 and 200.} The mass loss during heating to ~ 700 ° C. was measured as the mass (g) of water derived from silanol, and the amount of silanol groups (mmol / g) was calculated using the following formula.
Silanol group amount (mmol / g) = (2 x weight of water x 1000/18) / weight of _{SiO 2}

<Measurement of vacancy rate>
Nitrogen gas adsorption measurement of freeze-dried silica particles was performed by a multi-point method using liquid nitrogen using a specific surface area / pore distribution measuring device (manufactured by Shimadzu Corporation, trade name: ASAP2020). The sample (freeze-dried silica particles) subject 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) and the silica density (2.2 g / mL) of the micropores obtained by the t-plot method using the following formula.
Pore ratio (%) = 100 x pore volume / (1 / 2.2 + pore volume)

3. 3. Preparation method of silica particle dispersion liquid Silica particles (colloidal silica, Na amount 45 ppb / solid content, solid content, with respect to ion-exchanged water
An average primary particle diameter of 35 nm, an average secondary particle diameter of 71.8 mm, an association degree of 2.1), and 28 mass% aqueous ammonia (Kishida Chemical Co., Ltd. reagent special grade) were added as needed, and these were stirred for 30 minutes. Immediately after mixing to obtain a mixed solution, the mixed solution was 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 solution was described in Table 1. The silica particle dispersions for Examples 1 to 26 and Comparative Examples 1 to 6 were obtained by storing under the storage conditions (temperature and period of the mixed solution). The content of silica particles in the mixed solution was adjusted to 10% by mass, and the content of ammonia was adjusted so that the pH (25 ° C.) value of the silica particle dispersion was the value shown in Table 1. The "period" described in Table 1 is the above-mentioned "storage time", and is counted from the time when sufficient stirring (for example, stirring for 30 minutes) is completed until the concentration of the constituent components of the silica particle dispersion becomes uniform. ..

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

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

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

6. Polishing Method As described above, a polishing liquid composition obtained by mixing a silica particle dispersion liquid and an aqueous additive solution was prepared, and immediately used for finish polishing under the following polishing conditions ([finish polishing conditions]). The object to be polished is a silicon wafer (silicon single-sided mirror wafer having a diameter of 200 mm, conduction type: P, crystal orientation: 100, resistivity of 0.1 Ω · cm or more and less than 100 Ω · cm). Prior to the finish polishing, the silicon wafer was subjected to rough polishing in advance using a commercially available abrasive composition. The surface roughness (haze) of the silicon wafer after rough polishing was 2.680 ppb. This surface roughness (haze) is a value in the dark field wide oblique incident 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 (manufactured by Okamoto)
Polishing pad: Suede pad (Toray Coatex Co., Ltd. Asker hardness 64 thickness 1.37mm nap length 450um opening diameter 60um)
Wafer polishing pressure: 100 gf / cm ²
Surface plate rotation speed: 60 rpm
Polishing time: 10 minutes Supply speed of abrasive composition: 200 ml / min per silicon wafer
Abrasive composition temperature: 20 ° C
Carrier rotation speed: 60 rpm

7. Cleaning method After finish polishing, ozone cleaning and dilute hydrofluoric acid cleaning were performed on the silicon wafer as follows. In ozone cleaning, pure water containing 20 ppm of ozone is discharged from the nozzle at a flow rate of 1 L / min at 600 rpm.
It was injected for 3 minutes toward the center of the silicon wafer rotated by. At this time, the temperature of ozone water was set to room temperature. Next, dilute hydrofluoric acid washing was performed. In dilute hydrofluoric acid cleaning, pure water containing 0.5% ammonium hydrogen fluoride (special grade: Nacalai Tesque, Inc.) was sprayed from a nozzle toward the center of a silicon wafer rotating at a flow rate of 1 L / min at 600 rpm for 6 seconds. A total of two sets of the above ozone cleaning and dilute hydrofluoric acid cleaning were performed as one set, 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 a silicon wafer The surface roughness (haze) of a silicon wafer surface after cleaning is determined by the surface roughness measuring device "Surfscan SP1" (KLA Tencor). Dark field wide oblique incident channel (DWO) measured using
) Was used. Further, the surface defect (LPD) was measured at the same time as the Haze measurement, and was 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 value of surface defect (LPD), the smaller the number of surface defects. The polishing liquid compositions of Examples 1 to 26 and Comparative Examples 2 to 6 and the mixed liquids of the same composition containing silica particles, a basic compound, a water-soluble polymer compound, and an aqueous medium are supported. Obtain the values of surface defects (LPD) and haze (DWO) when the one-component polishing solution composition obtained by storing (aging) at the same storage temperature as in the examples and comparative examples for 2 weeks is used for polishing. , Each of these values is set to 1.0 (reference value), and surface defects (LPD) and haze when the polishing solution compositions of Examples 1 to 26 and Comparative Examples 2 to 6 are used for polishing according to the following evaluation criteria. (DWO) was evaluated. Regarding the polishing liquid composition of Comparative Example 1, the surface defects (LPD) and the surface roughness (haze) could not be evaluated because the silica particles were severely aggregated.

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

(2) Wetness The area of the hydrophilized part (wet part) on 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, the average value was evaluated according to the following evaluation criteria, and the results are shown in Table 1. Regarding the polishing liquid composition of Comparative Example 1, the wettability could not be evaluated because the silica particles were severely aggregated.
(Evaluation criteria)
A: Wet part area ratio is 95 or more B: Wet part area ratio is 90% or more and less than 95% C: Wet part area ratio is 50% or more and less than 90% D: Wet part 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 liquid is used, the surface defect (LPD) and the surface roughness (haze) of the polished silicon wafer are higher than those when the polishing liquid composition of the comparative example is used. Is small. Further, a silica particle dispersion obtained 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 the polishing liquid composition of the example obtained by mixing and the additive aqueous solution was used, the surface defects (LPD) and the surface roughness of the polished silicon wafer were higher than those of the case of using the polishing liquid composition of the comparative example. The haze is small. Further, 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 useful in mass production of semiconductor substrates because it can stably reduce the surface roughness (haze) and surface defects (LPD) of the polished silicon wafer surface.

Claims (17)

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 aqueous additive solution containing a water-soluble polymer compound and an aqueous medium.
BET ratio obtained by dividing the BET specific surface area of the freeze-dried silica particles obtained by freeze-drying the silica particle dispersion by the BET specific surface area of the 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 1 , wherein the silanol group amount 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 1 or 2 , wherein the pore ratio of the surface of the silica particles after freeze-drying is 1.5% or more and 30% or less. The water-soluble polymer compound is a copolymer of polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, polyethylene glycol, polyoxyethylene, N-hydroxyethylacrylamide (HEAA), and N-isopropylacrylamide (NIPAM) and acrylamide (AAm). The polishing liquid composition for a silicon wafer according to any one of claims 1 to 3 , which comprises at least one water-soluble polymer compound selected from the group consisting of a copolymer of. The polishing liquid composition for a silicon wafer according to any one of claims 1 to 4 , wherein the aqueous additive solution contains a polyoxyalkylene compound. It contains 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 BET specific surface area of the silica particles after freeze-drying obtained by freeze-drying the silica particles in the silica particle dispersion liquid is the air-dried silica particles obtained by air-drying the silica particles in the silica particle dispersion liquid. BET specific surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) obtained by dividing by the BET specific surface area of the silicon wafer is 1.3 or more and 10 or less. kit. The polishing liquid composition kit for a silicon wafer according to claim 6 , wherein the silanol group amount 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 kit for a silicon wafer according to claim 6 or 7 , wherein the pore ratio of the surface of the silica particles after freeze-drying is 1.5% or more and 30% or less. The water-soluble polymer compound is a copolymer of polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, polyethylene glycol, polyoxyethylene, N-hydroxyethylacrylamide (HEAA), and N-isopropylacrylamide (NIPAM) and acrylamide (AAm). The polishing liquid composition kit for silicon wafer according to any one of claims 6 to 8 , which comprises at least one water-soluble polymer compound selected from the group consisting of a copolymer of. The polishing liquid composition kit for a silicon wafer according to any one of claims 6 to 9 , wherein the additive aqueous solution contains a polyoxyalkylene compound. The method for manufacturing a polishing liquid composition kit for a silicon wafer according to any one of claims 6 to 10.
A step of mixing a water-soluble polymer compound and an aqueous medium to obtain an aqueous additive solution,
A step of obtaining a silica particle dispersion by holding a mixed solution having a pH of 9 or more and 11 or less at 25 ° C. obtained by mixing silica particles, a basic compound and an aqueous medium at 10 ° C. or more and 80 ° C. or less for 1 day or more. And, a method for manufacturing a polishing liquid composition kit for a silicon wafer. 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 the freeze-dried silica particles obtained by freeze-drying the silica particle dispersion by the BET specific surface area of the air-dried silica particles obtained by air-drying the silica particle dispersion. A silica particle dispersion having a surface area ratio (BET specific surface area of freeze-dried silica particles / BET specific surface area of air-dried silica particles) of 1.3 or more and 10 or less. A method for producing a polishing liquid composition for a silicon wafer, which comprises a step of mixing the silica particle dispersion liquid according to claim 12 with an aqueous additive solution containing a water-soluble polymer compound and an aqueous medium. A method for manufacturing a semiconductor substrate, which comprises a step of polishing a silicon wafer to be polished using the polishing liquid composition for a silicon wafer according to any one of claims 1 to 5. A method for polishing a silicon wafer to be polished, which comprises a step of polishing the silicon wafer to be polished using the polishing liquid composition for a silicon wafer according to any one of claims 1 to 5. A method for manufacturing a semiconductor substrate, which comprises a step of polishing a silicon wafer to be polished using the polishing liquid composition kit for a silicon wafer according to any one of claims 6 to 10. A method for polishing a silicon wafer to be polished, which comprises a step of polishing the silicon wafer to be polished using the polishing liquid composition kit for a silicon wafer according to any one of claims 6 to 10.