JP7105089B2 - Silicon wafer manufacturing method - Google Patents

Description

The present invention relates to a silicon wafer manufacturing method and a semiconductor substrate manufacturing method.

2. Description of the Related Art In recent years, the design rules of semiconductor devices have become finer due to the increasing demand for higher recording capacity of semiconductor memories. For this reason, the depth of focus in photolithography performed in the manufacturing process of semiconductor devices has become shallower, and the demand for reduction of surface defects (LPD: light point defects) and surface roughness (haze) of silicon wafers (bare wafers) has become more and more severe. It's becoming

For the purpose of improving the quality of silicon wafers, the polishing process for polishing silicon wafers includes a lapping (coarse polishing) process for flattening silicon wafers obtained by slicing a silicon single crystal ingot into thin discs. and a final polishing step of mirror-finishing the surface of the silicon wafer after etching the lapped silicon wafer. In particular, the final polishing performed in the final stage of polishing is performed for the purpose of suppressing haze and reducing LPD such as particles, scratches, and pits by improving the wettability (hydrophilization) of the polished silicon wafer surface. there is

A polishing liquid composition containing silica particles, hydroxyethyl cellulose (HEC), polyethylene oxide, and an alkaline compound is disclosed as a polishing liquid composition used for polishing silicon wafers for the purpose of improving the haze level. (Patent Document 1). For the purpose of achieving both reduction of surface roughness (haze) and reduction of surface defects (LPD), the ratio of the number of oxygen atoms derived from hydroxyl groups to the number of oxygen atoms derived from polyoxyalkylene (number of oxygen atoms derived from hydroxyl groups / A polishing composition for silicon wafers containing a water-soluble polymer having a polyoxyalkylene-derived number of oxygen atoms) is disclosed (Patent Document 2). A polyvinyl alcohol resin having a 1,2-diol structure in its side chain and a solution having a pH of 2.0 or higher are used for the purpose of suppressing the aggregation of abrasive grains and reducing contamination of the surface of the polished object. has been disclosed a polishing composition for silicon wafers containing abrasive grains chemically modified on the surface so that the surface has a negative zeta potential and no isoelectric point (Patent Document 3). Disclosed is a polishing composition for silicon wafers containing hydroxypropylmethyl cellulose and abrasive grains having a negative zeta potential in the polishing composition for the purpose of suppressing deterioration of smoothness and reducing the number of defects. (Patent Document 4). Although it is neither a polishing composition nor a composition used for silicon wafer surfaces, it is expected to be able to remove contaminants from the surface of a substrate for semiconductor devices after a CMP process, and to clean the substrate surface in a short period of time. For the purpose, polyvinylpyrrolidone and polyethylene oxide-polypropylene oxide block copolymer are contained as a polymer flocculant, and the particle size of the fine particles is increased by aggregation, and the zeta potential of the fine particles is made negative so that the fine particles are deposited on the surface of the semiconductor device substrate. (Patent Document 5).

JP 2004-128089 A WO2015/060293 WO2014/084091 JP 2014-154707 A JP 2012-94852 A

However, since HEC is made from cellulose, which is a natural fiber, a polishing composition using HEC contains water-insoluble matter derived from cellulose, and the water-insoluble matter tends to agglomerate silica particles with the water-insoluble matter as a nucleus. Then, the presence of aggregates of silica particles and the water-insoluble matter itself may cause an increase in LPD.

In addition, since the polymer contained in the polishing liquid composition is attached to the surface of the silicon wafer polished in the polishing step (hereinafter also referred to as "silicon wafer after polishing"), for example, the silicon wafer after polishing and the pad Water is supplied between and, and the pad is moved relative to the silicon wafer after polishing while the pad is in contact with the silicon wafer after polishing. , which hinders LPD reduction.

Therefore, the present invention provides a method for manufacturing a silicon wafer and a method for manufacturing a semiconductor substrate that can reduce the LPD of a rinsed silicon wafer (hereinafter also referred to as a "rinsed silicon wafer").

The method for producing a silicon wafer of the present invention comprises
a polishing step of polishing a silicon wafer to be polished using a polishing liquid composition containing silica particles, a water-soluble polymer B, a nitrogen-containing basic compound, and an aqueous medium;
a rinsing step of rinsing the polished silicon wafer with a rinsing agent composition containing a water-soluble polymer A and an aqueous medium;
and a cleaning step of cleaning the rinsed silicon wafer, wherein the water-soluble polymer B is
Consists of the water-soluble polymer B, silica particles, water and, if necessary, hydrochloric acid or ammonia, the concentration of the water-soluble polymer B is 0.01% by mass, the concentration of the silica particles is 0.1% by mass, A water-soluble polymer-containing aqueous silica dispersion (aqueous dispersion s) having a pH of 10.0 at 25° C. has a zeta potential z, silica particles, water, and, if necessary, hydrochloric acid or ammonia. The difference (zz ₀ ) between the zeta potential z ₀ of an aqueous silica dispersion having a concentration of 0.1% by mass and a pH of 10.0 at 25° C. (aqueous dispersion s ₀ ) is less than 15 mV. is a polymer,
The water-soluble polymer A is
Consists of the water-soluble polymer A, silica particles, water and, if necessary, hydrochloric acid or ammonia, the concentration of the water-soluble polymer A is 0.1% by mass, the concentration of the silica particles is 0.1% by mass, A water-soluble polymer-containing aqueous dispersion of silica (aqueous dispersion S) having a pH of 7.0 at 25° C. has a zeta potential Z, silica particles, water, and optionally hydrochloric acid or ammonia, and the silica particles The difference (ZZ ₀ ) between the zeta potential Z ₀ of an aqueous silica dispersion (aqueous dispersion S ₀ ) having a concentration of 0.1% by mass and a pH of 7.0 at 25° C. is 25 mV or less. It is a flexible polymer.

The method for manufacturing a semiconductor substrate of the present invention includes the step of manufacturing a silicon wafer by the method for manufacturing a silicon wafer of the present invention.

INDUSTRIAL APPLICABILITY The present invention relates to a silicon wafer manufacturing method and a semiconductor substrate manufacturing method capable of reducing the LPD of a silicon wafer after polishing.

In the present invention, the polishing liquid composition contains a specific water-soluble polymer B, and the rinse agent composition contains a specific water-soluble polymer A, thereby making it possible to reduce the LPD of silicon wafers. based on The water-soluble polymer B is composed of the water-soluble polymer B, silica particles, water, and, if necessary, hydrochloric acid or ammonia. is 0.1% by mass and the zeta potential z of a water-soluble polymer-containing aqueous silica dispersion (aqueous dispersion s) having a pH of 10.0 at 25 ° C., silica particles, water and, if necessary, hydrochloric acid or ammonia The difference (zz ₀ ) between the zeta potential z ₀ of the aqueous silica dispersion (aqueous dispersion s ₀ ) having a silica particle concentration of 0.1% by mass and a pH of 10.0 at 25° C. is , less than 15 mV. On the other hand, the water-soluble polymer A is composed of the water-soluble polymer A, silica particles, water and, if necessary, hydrochloric acid or ammonia. The zeta potential Z of a water-soluble polymer-containing silica water dispersion (aqueous dispersion S) having a particle concentration of 0.1% by mass and a pH of 7.0 at 25° C., silica particles, water and, if necessary, hydrochloric acid or _ammonia , and the difference ( _Z- Z ₀ ) is a water-soluble polymer with a Z 0 of 25 mV or less.

In the silicon wafer manufacturing method of the present invention, the mechanism of the effect of the present invention that the LPD of the silicon wafer after rinsing can be reduced is presumed to be as follows.

In the method for producing a silicon wafer of the present invention, in the polishing step, a polishing composition containing the water-soluble polymer B having a property that the zeta potential difference (zz ₀ ) is less than 15 mV is used. However, it is moderately adsorbed to the surface of the silicon wafer, exhibits good wettability, and suppresses adhesion of particles to the surface of the silicon wafer, which is considered to be caused by drying of the surface of the silicon wafer. In the rinsing step, when the rinsing treatment using the rinsing agent composition is started, the pad is adsorbed on the surfaces of the polished silicon wafer and the silica particles due to the physical force when the pad is moved relative to the polished silicon wafer. The water-soluble polymer B contained in the rinse agent composition and having a zeta potential difference (ZZ ₀ ) of 25 mV or less is replaced with the water-soluble polymer A described above. Then, reattachment of the silica particles to the surface of the rinsed silicon wafer is suppressed, so that the amount of silica particles remaining on the rinsed silicon wafer to be subjected to the cleaning process can be significantly reduced. In addition, even if both the water-soluble polymer B and the water-soluble polymer A are adsorbed to the silica particles, the zeta potential of the silica particles does not change greatly, and the zeta potential of the silica particles can be maintained at a large negative value. Aggregation of silica particles is suppressed in both the polishing step and the rinsing step. Therefore, by using the polishing liquid composition containing the water-soluble polymer B in the polishing step and using the rinse agent composition containing the water-soluble polymer A in the rinsing step, the LPD of the silicon wafer after rinsing can be reduced. presumed to be

[Method for manufacturing semiconductor substrate]
An example of the method for producing a semiconductor substrate of the present invention includes a polishing step of polishing a silicon wafer to be polished (also referred to as a "substrate to be polished") using a polishing liquid composition containing abrasive grains, and polishing the silicon wafer after polishing. , a rinsing step of rinsing with the rinsing agent composition of the present invention, and a cleaning step of cleaning the silicon wafer rinsed in the rinsing step (also referred to as “rinsed silicon wafer”).

An example of a semiconductor substrate is, for example, a silicon wafer, and an example of a method for manufacturing a semiconductor substrate of the present invention is a method for manufacturing a silicon wafer. Another example of the method for producing a semiconductor substrate of the present invention is a method for producing a semiconductor substrate comprising a step of producing a silicon wafer by the method for producing a silicon wafer of the present invention, wherein the step uses a polishing composition. It includes a polishing step of polishing a silicon wafer to be polished, a rinsing step of rinsing the polished silicon wafer with the rinse agent composition of the present invention, and a cleaning step of cleaning the rinsed silicon wafer.

The polishing step includes a lapping (coarse polishing) step of flattening a silicon wafer obtained by slicing a silicon single crystal ingot into thin discs, and etching the lapped silicon wafer, and then polishing the surface of the silicon wafer. There is a final polishing process for mirror finishing.

In the polishing step, for example, the polishing liquid composition is supplied between the silicon wafer to be polished and the pad, and the pad is moved relative to the silicon wafer to be polished while the silicon wafer to be polished and the pad are in contact with each other. . Polishing conditions such as the type of pad, the number of rotations of the pad, the number of rotations of the substrate to be polished, the polishing load set in the polishing apparatus provided with the pad, the supply rate of the polishing liquid composition, and the polishing time are conventionally known polishing. be the same as the conditions.

The abrasive composition used in the polishing step contains silica particles as abrasive grains and water-soluble polymer B from the viewpoint of reducing the LPD of silicon wafers.

In the rinsing step, for example, a rinse agent composition is supplied between the polished silicon wafer and the pad, and the pad is moved relative to the polished silicon wafer while the polished silicon wafer and the pad are in contact with each other. . The rinsing process in the rinsing process can be performed using a polishing apparatus used in the polishing process. The type of pad, the number of rotations of the pad, the number of rotations of the silicon wafer after polishing, the load set in the polishing apparatus equipped with the pad, the supply rate of the rinse agent composition, etc. may be the same as the corresponding conditions in the polishing step. can be different. The rinsing time is preferably 1 second or more, more preferably 3 seconds or more from the viewpoint of suppressing adhesion of abrasive grains, and preferably 60 seconds or less, more preferably 30 seconds or less from the viewpoint of improving productivity. . Here, the rinse time means the time during which the rinse agent composition is supplied.

The rinsing step may include a water rinsing treatment using water as a rinsing liquid prior to the rinsing treatment performed using the rinse agent composition. The water rinse treatment time is preferably 2 seconds or more and 30 seconds or less.

The pad used in the rinsing step may be the same as the pad used in the polishing step, and may be of any type such as nonwoven fabric type or suede type. Also, the pad used in the polishing step may be used in the rinsing step as it is without replacement, and in this case, the pad may contain some abrasive grains of the polishing composition. The rinsing step can also be performed on the silicon wafer still attached to the polishing apparatus immediately after the polishing step.

The temperature of the rinse agent composition used in the rinse step is preferably 5 to 60°C.

The rinsing step is preferably performed at least after the finish polishing step, but may be performed after each step of the rough polishing step and the finish polishing step.

In the cleaning step, for example, the rinsed silicon wafer is immersed in a cleaning agent, or the cleaning agent is injected onto the surface of the rinsed silicon wafer to be cleaned. A conventionally known cleaning agent may be used as the cleaning agent, and examples thereof include an aqueous solution containing ozone and an aqueous solution containing ammonium hydrogen fluoride. The cleaning time may be set according to the cleaning method.

The semiconductor substrate manufacturing method of the present invention may further include, in addition to the silicon wafer manufacturing process, an element isolation film forming process, an interlayer insulating film planarizing process, a metal wiring forming process, and the like.

The polishing liquid composition used in the polishing step contains silica particles, a water-soluble polymer B, a nitrogen-containing basic compound, and an aqueous medium from the viewpoint of both improving the polishing rate and reducing the LPD.

[Silica particles]
The silica particles contained in the polishing composition are more preferably colloidal silica from the viewpoint of improving the surface smoothness of silicon wafers, and alkoxysilane from the viewpoint of preventing contamination of silicon wafers with alkali metals, alkaline earth metals, and the like. preferably obtained from the hydrolyzate of

The average primary particle size of the silica particles contained in the polishing composition is preferably 5 nm or more, more preferably 10 nm or more, from the viewpoint of ensuring a high polishing rate, and preferably 50 nm or less from the viewpoint of reducing LPD. , and more preferably 45 nm or less. The average primary particle size of silica particles can be calculated using the specific surface area S (m ² /g) calculated by the BET (nitrogen adsorption) method.

The degree of association of silica particles is preferably 1.1 or more and 3.0 or less, more preferably 1.8 or more and 2.5 or less, from the viewpoint of securing a high polishing rate and reducing LPD. 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, for example, using the apparatus described in Examples.
Degree of association = average secondary particle size / average primary particle size

The average secondary particle size of the silica particles is preferably 40 nm or more, more preferably 50 nm or more, still more preferably 60 nm or more, from the viewpoint of ensuring a high polishing rate, and preferably 100 nm or less, and 80 nm from the viewpoint of reducing LPD. The following is more preferable, and 75 nm or less is even more preferable.

The content of silica particles contained in the polishing composition is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, from the viewpoint of ensuring a high polishing rate. From the viewpoint of suppressing aggregation of silica particles in the polishing composition and improving dispersion stability, the amount is preferably 10% by mass or less, more preferably 7.5% by mass or less.

[Water-soluble polymer B]
The water-soluble polymer B is a water-soluble polymer in which the difference (zz ₀ ) between the zeta potential z of the aqueous dispersion s and the zeta potential z ₀ of the aqueous dispersion s ₀ is less than 15 mV. Here, the aqueous dispersion s is composed of the water-soluble polymer B, silica particles, water, and, if necessary, hydrochloric acid or ammonia. It is a 0.1% by mass silica water dispersion containing a water-soluble polymer having a pH of 10.0 at 25°C. The aqueous dispersion s ₀ is an aqueous silica dispersion containing silica particles, water, and optionally hydrochloric acid or ammonia, having a silica particle concentration of 0.1% by mass and a pH of 10.0 at 25°C. . Zeta potential can be measured by the method described in Examples. When the water-soluble polymer B consists of two or more water-soluble polymers, a mixture of two or more water-soluble polymers has the property that the difference (zz ₀ ) is less than 15 mV. When the water-soluble polymer B is a mixture of two or more water-soluble polymers, "the concentration of the water-soluble polymer B is 0.01% by mass" means that the mixture in the aqueous dispersion s is 0.01% by mass, in other words, the total concentration of each water-soluble polymer in the aqueous dispersion s is 0.01% by mass. "Water-soluble" means having a solubility of 2 g/100 ml or more in water at 25°C.

From the viewpoint of LPD reduction, the zeta potential difference (zz ₀ ) is less than 15 mV, preferably 11 mV or less, more preferably 9 mV or less, and 1 mV or more.

The zeta potential z ₀ of the aqueous dispersion s ₀ is, for example, a predetermined value within the range of -50 mV to -70 mV, and as an example, it is adjusted using a silica undiluted solution ("PL-3" manufactured by Fuso Chemical Co., Ltd.). is the zeta potential (eg, -61 mV) of the aqueous dispersion z ₀ obtained.

The ratio (D/D ₀ ) of the secondary particle size D of the silica particles in the aqueous dispersion s and the secondary particle size D ₀ of the silica particles in the aqueous dispersion s ₀ is from the viewpoint of LPD reduction. , preferably less than 1.10, more preferably 1.05 or less, and from the viewpoint of improving the polishing rate, preferably 1.00 or more, more preferably 1.04 or more.

The secondary particle size D ₀ of the silica particles in the aqueous dispersion s ₀ is, for example, a predetermined value within the range of 64 to 73 nm and a predetermined value within the range of 66 to 69 nm. (“PL-3” manufactured by Fuso Chemical Co., Ltd.) as a source of _silica particles.

From the viewpoint of reducing LPD, the water-soluble polymer B is at least one selected from the group consisting of polyglycerin, polyglycerin derivatives, polyglycidol, polyglycidol derivatives, polyacrylamides, polyvinyl alcohol derivatives, and polyvinyl alkyl ethers. be.

From the viewpoint of reducing LPD, the polyglycerin derivative is preferably polyglycerin alkyl ether, polyglycerin dialkyl ether, polyglycerin fatty acid ester, polyethylene oxide-added polyglycerin, polypropylene oxide-added polyglycerin, aminated polyglycerin, etc. Polyglycerin alkyl ether is more preferred. These may be used singly or in combination of two or more.

Polyglycidol derivatives are preferably polyglycidol alkyl ethers, polyglycidol dialkyl ethers, polyglycidol fatty acid esters, polyethylene oxide-added polyglycidol, polypropylene oxide-added polyglycidol, aminated polyglycidol, and the like, from the viewpoint of reducing LPD. These may be used singly or in combination of two or more. The number of carbon atoms in the hydrophobic group of the polyglycidol derivative is preferably 4 or more, more preferably 6 or more, and preferably 22 or less, more preferably 18 or less.

From the viewpoint of reducing LPD, the polyvinyl alcohol derivative is preferably anion-modified polyvinyl alcohol, more preferably sulfonic acid-modified polyvinyl alcohol, or the like.

From the viewpoint of reducing LPD, polyvinyl methyl ether and the like are preferable as the polyvinyl alkyl ether. The number of carbon atoms in the hydrophobic group of the polyvinyl alkyl ether is preferably 3 or less, more preferably 2 or less, and still more preferably 1.

From the viewpoint of reducing LPD, the water-soluble polymer B is more preferably polyglycerin, polyglycerin alkyl ether, polyglycerin dialkyl ether, polyglycerin fatty acid ester, sulfonic acid-modified polyvinyl alcohol, polyvinyl methyl ether, and At least one selected from polyacrylamide, more preferably at least one selected from polyglycerin, polyglycerin alkyl ether, polyacrylamide, sulfonic acid-modified polyvinyl alcohol, and polyvinyl methyl ether, still more preferably poly It is at least one water-soluble polymer selected from glycerin, polyglycerin alkyl ether, and polyacrylamide, and more preferably at least one selected from polyglycerin and polyglycerin alkyl ether. The number of carbon atoms in the hydrophobic group of the polyglycerol derivative is preferably 6 or more, more preferably 8 or more, and is preferably 22 or less, more preferably 18 or less.

The weight-average molecular weight of the water-soluble polymer B is preferably 1,000 or more, more preferably 2,000 or more, and still more preferably 3,000 or more, from the viewpoint of both improving the polishing rate and reducing the LPD. It is preferably 5 million or less, more preferably 3 million or less, still more preferably 1 million or less. The weight average molecular weight of the water-soluble polymer B can be measured by the method described in Examples.

From the viewpoint of reducing LPD, the water-soluble polymer B is preferably a pentamer or more, more preferably a decamer or more, and still more preferably a 15mer or more. 000-mer or less, more preferably 500-mer or less, still more preferably 200-mer or less, still more preferably 150-mer or less, still more preferably 100-mer or less.

The content of the water-soluble polymer B in the polishing composition is preferably 0.001% by mass or more, more preferably 0.003% by mass or more, and still more preferably 0.005% by mass, from the viewpoint of improving the polishing rate. % or more, and from the same viewpoint, it is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less.

[Nitrogen-containing basic compound]
The nitrogen-containing basic compound contained in the polishing composition is at least one nitrogen-containing basic compound selected from amine compounds and ammonium compounds from the viewpoint of ensuring a high polishing rate and reducing haze and LPD, For example, ammonia, ammonium hydroxide, ammonium carbonate, ammonium hydrogen carbonate, dimethylamine, trimethylamine, diethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N-methyl-N,N-diethano- Lamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N,N-dibutylethanolamine, N-(β-aminoethyl)ethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, Ethylenediamine, hexamethylenediamine, piperazine hexahydrate, anhydrous piperazine, 1-(2-aminoethyl)piperazine, N-methylpiperazine, diethylenetriamine, tetramethylammonium hydroxide, and hydroxylamine. Among them, ammonia and a mixture of ammonia and hydroxylamine are preferred, and ammonia is more preferred.

The content of the nitrogen-containing basic compound contained in the polishing composition is preferably 0.001% by mass or more, more preferably 0.005, from the viewpoint of reducing haze and LPD of silicon wafers and ensuring a high polishing rate. % by mass or more, and preferably 1% by mass or less, more preferably 0.5% by mass or less, from the viewpoint of reducing haze and LPD of silicon wafers.

[Aqueous medium]
The aqueous medium contained in the polishing composition may be the same as the aqueous medium contained in the rinse agent composition of the present invention. The content of the aqueous medium in the polishing composition may be, for example, the remainder after removing the silica particles, the water-soluble polymer B, the nitrogen-containing basic compound, and optional components described below.

The pH of the polishing composition at 25° C. is preferably 8 or higher, more preferably 9 or higher, still more preferably 10 or higher, from the viewpoint of ensuring a high polishing rate, and preferably 12 or lower from the viewpoint of safety. , more preferably 11 or less. The adjustment of pH can be carried out by appropriately adding a nitrogen-containing basic compound and/or a pH adjuster. Here, the pH at 25° C. can be measured using a pH meter (HM-30G, manufactured by Toa Denpa Kogyo Co., Ltd.), and is the value one minute after the electrode is immersed in the polishing composition.

The polishing liquid composition can be produced, for example, by a production method including a step of blending silica particles, water-soluble polymer B, an aqueous medium, a nitrogen-containing basic compound, and optionally optional ingredients by a known method. The optional component includes at least one optional component selected from water-soluble polymers other than the water-soluble polymer B, pH adjusters, preservatives, alcohols, chelating agents and nonionic surfactants.

[Rinse agent composition]
The rinse agent composition used in the rinse step contains a water-soluble polymer A, an aqueous medium, and optional components within a range that does not interfere with the effects of the present invention. Details of optional components will be described later.

[Water-soluble polymer A]
The water-soluble polymer A is a water-soluble polymer having the property that the difference (ZZ ₀ ) between the zeta potential Z of the aqueous dispersion S and the zeta potential Z ₀ of the aqueous dispersion S ₀ is 25 mV or less. . Here, the aqueous dispersion S is composed of the water-soluble polymer A, silica particles, water, and, if necessary, hydrochloric acid or ammonia. It is a silica aqueous dispersion containing 0.1% by mass and having a pH of 7.0 at 25° C. and containing a water-soluble polymer. The aqueous dispersion S ₀ is an aqueous silica dispersion containing silica particles, water, and optionally hydrochloric acid or ammonia, having a silica particle concentration of 0.1% by mass and a pH of 7.0 at 25°C. . Zeta potential can be measured by the method described in Examples. When the water-soluble polymer A consists of two or more water-soluble polymers, a mixture of two or more water-soluble polymers has the property that the difference (ZZ ₀ ) is 25 mV or less. When the water-soluble polymer A is a mixture of two or more water-soluble polymers, "the concentration of the water-soluble polymer A is 0.1% by mass" means that the mixture in the aqueous dispersion S is 0.1% by mass, in other words, the total concentration of each water-soluble polymer in the aqueous dispersion S is 0.1% by mass. From the viewpoint of reducing LPD, the potential difference (ZZ ₀ ) is preferably smaller than the potential difference (zz ₀ ).

When the water-soluble polymer A consists only of the water-soluble polymer a1 described later, the difference (ZZ ₀ ) is 25 mV or less, preferably less than 15 mV, preferably 9 mV, from the viewpoint of suppressing aggregation of silica particles. Below, it is more preferably 7 mV or less and 1 mV or more.

When the water-soluble polymer A is a mixture of a water-soluble polymer a1 and a water-soluble polymer a2, which will be described later, the difference (ZZ ₀ ) is 25 mV or less from the viewpoint of suppressing aggregation of silica particles. It is preferably less than 15 mV, more preferably less than 12 mV, still more preferably less than 9 mV, and more than 3 mV.

The zeta potential Z ₀ of the aqueous dispersion S ₀ is, for example, a predetermined value within the range of -40 mV to -50 mV, and as an example, it is adjusted using a silica stock solution (“PL-3” manufactured by Fuso Chemical Co., Ltd.). is the zeta potential (eg, −46 mV) of the aqueous dispersion S ₀ .

When the water-soluble polymer A consists of only the water-soluble polymer a1 described later, the water-soluble polymer A has a secondary particle size of the silica particles in the aqueous dispersion S from the viewpoint of suppressing aggregation of the silica particles. The ratio (d/d ₀ ) between d and the secondary particle size d ₀ of the silica particles in the aqueous dispersion S ₀ is preferably 1.35 or less, more preferably 1.17 or less, and still more preferably 1 .10 or less, more preferably 1.08 or less, and from the viewpoint of LPD reduction, it is preferably 1.00 or more, more preferably 1.02 or more, and still more preferably 1.04. It is a water-soluble polymer having a value of 1.05 or more, and more preferably 1.05 or more.

When the water-soluble polymer A is a mixture of a water-soluble polymer a1 described later and a water-soluble polymer a2 described later, the water-soluble polymer A is added to the aqueous dispersion from the viewpoint of suppressing aggregation of silica particles. The ratio (d/d ₀ ) of the secondary particle size d of the silica particles in S to the secondary particle size d ₀ of the silica particles in the aqueous dispersion S ₀ is preferably 1.35 or less, more preferably is 1.34 or less, more preferably 1.33 or less, even more preferably 1.32 or less, and is a water-soluble polymer that is preferably 1.00 or more, more preferably 1 from the viewpoint of LPD reduction. 0.25 or more, more preferably 1.30 or more, still more preferably 1.31 or more.

The secondary particle size d ₀ of the silica particles in the aqueous dispersion S ₀ is, for example, a predetermined value within the range of 64 to 73 nm, preferably a predetermined value within the range of 66 to 69 nm. This is the secondary particle size (for example, 68.4 nm) of silica particles in aqueous dispersion S ₀ containing silica undiluted solution (“PL-3” manufactured by Fuso Chemical Co., Ltd.) as a source of silica particles.

From the viewpoint of reducing LPD, the content of the water-soluble polymer A in the rinse agent composition is preferably 0.001% by mass or more, more preferably 0.015% by mass or more, and still more preferably 0.020% by mass or more. Still more preferably 0.025% by mass or more, still more preferably 0.03% by mass or more, and from the same viewpoint, preferably 1.0% by mass or less, more preferably 0.7% by mass or less, It is more preferably 0.4% by mass or less, even more preferably 0.1% by mass or less, and even more preferably 0.08% by mass or less.

From the viewpoint of LPD reduction, the water-soluble polymer A preferably contains at least one water-soluble polymer a1 selected from the group consisting of polyglycerin, polyglycerin derivatives, polyglycidol, and polyglycidol derivatives.

As the polyglycerin derivative, one obtained by adding a functional group to polyglycerin via an ether bond or an ester bond is preferable, and one obtained by adding a functional group via an ether bond is more preferable.

From the viewpoint of reducing LPD, the polyglycerin derivative is preferably polyglycerin alkyl ether, polyglycerin dialkyl ether, polyglycerin fatty acid ester, polyethylene oxide-added polyglycerin, polypropylene oxide-added polyglycerin, aminated polyglycerin, etc. Polyglycerin alkyl ether is more preferred. These may be used singly or in combination of two or more.

Polyglycidol derivatives are preferably polyglycidol alkyl ethers, polyglycidol dialkyl ethers, polyglycidol fatty acid esters, polyethylene oxide-added polyglycidol, polypropylene oxide-added polyglycidol, aminated polyglycidol, and the like, from the viewpoint of reducing LPD. These may be used singly or in combination of two or more. The number of carbon atoms in the hydrophobic group of the polyglycidol derivative is preferably 6 or more, more preferably 8 or more, and is preferably 22 or less, more preferably 18 or less.

From the viewpoint of reducing LPD, the water-soluble polymer a1 is more preferably at least one water-soluble polymer selected from polyglycerin, polyglycerin alkyl ether, polyglycerin dialkyl ether, and polyglycerin fatty acid ester. and more preferably at least one water-soluble polymer a3 selected from polyglycerin and polyglycerin alkyl ether. Two or more of the above water-soluble polymers a1 may be selected and used, and from the viewpoint of reducing LPD, the rinse agent composition preferably contains both polyglycerin and polyglycerin alkyl ether. . The number of carbon atoms in the hydrophobic group of the polyglycerol derivative is preferably 6 or more, more preferably 8 or more, and is preferably 22 or less, more preferably 18 or less.

When the water-soluble polymer a1 contains polyglycerin and polyglycerin alkyl ether, the mass ratio of these (polyglycerin/polyglycerin alkyl ether) is preferably 0.5 or more, more preferably 0.5 or more, from the viewpoint of reducing LPD. It is 1.0 or more, more preferably 2.0 or more, and from the same viewpoint, it is preferably 10 or less, more preferably 6.0 or less, and still more preferably 5.0 or less.

The weight-average molecular weight of the water-soluble polymer a1 is preferably 500 or more, more preferably 700 or more, and still more preferably 900 or more from the viewpoint of reducing LPD. It is more preferably 500,000 or less, still more preferably 100,000 or less, even more preferably 30,000 or less, still more preferably 25,000 or less, still more preferably 10,000 or less. The weight average molecular weight of the water-soluble polymer A can be measured by the method described in Examples.

From the viewpoint of reducing LPD, the water-soluble polymer a1 is preferably a pentamer or higher, more preferably a 10-mer or higher, and still more preferably a 15-mer or higher. 000-mer or less, more preferably 500-mer or less, still more preferably 200-mer or less, even more preferably 150-mer or less, still more preferably 100-mer or less.

The weight average molecular weight of the water-soluble polymer a3 is preferably 500 or more, more preferably 700 or more, still more preferably 900 or more, from the viewpoint of LPD reduction, and from the same viewpoint, preferably 30,000 or less. is 25,000 or less, even more preferably 10,000 or less.

From the viewpoint of reducing LPD, the water-soluble polymer A is the water-soluble polymer a1 and a water-soluble polymer containing a betaine structure (hereinafter, "water-soluble polymer containing a betaine structure" is referred to as "water-soluble polymer a2" (sometimes abbreviated as )).

[Water-soluble polymer containing betaine structure]
In the present application, the term "betaine structure" refers to a structure having positive and negative charges in the same molecule and having neutralized charges. The betaine structure has the positive and negative charges preferably in non-adjacent positions and preferably across one or more atoms.

As the water-soluble polymer a2, from the viewpoint of reducing LPD, a polymer of a monomer containing a betaine structure, a copolymer of a monomer containing a betaine structure and a monomer containing a hydrophobic group, a monomer containing a betaine structure Copolymer of a monomer and a monomer containing a hydroxyl group, a copolymer of a monomer containing a betaine structure and a monomer containing an oxyalkylene group, a monomer containing a betaine structure and a monomer containing an amino group and a copolymer of a monomer containing a betaine structure and a monomer containing a quaternary ammonium group. Copolymers of monomers containing groups are more preferred.

Examples of the betaine structure include sulfobetaine, carbobetaine, phosphobetaine, etc. From the viewpoint of reducing LPD, carbobetaine and phosphobetaine are more preferred, and phosphobetaine is even more preferred.

From the viewpoint of reducing LPD, the structural unit A derived from a monomer containing a betaine structure is preferably a structural unit represented by the following formula (1).

In the above formula (1),
R ¹ to R ³ : same or different, hydrogen atom, methyl group or ethyl group R ⁴ : alkylene group having 1 to 4 carbon atoms, or -Y ¹ -OPO ₃ ^- -Y ² -
Y ¹ and Y ² : the same or different alkylene groups having 1 to 4 carbon atoms R ⁵ and R ⁶ : the same or different hydrocarbon groups having 1 to 4 carbon atoms X ¹ : O or NR ⁷
R ⁷ : Hydrogen atom or hydrocarbon group having 1 to 4 carbon atoms X ² : Hydrocarbon group having 1 to 4 carbon atoms, —R ¹⁷ SO ₃ ⁻ , or —R ¹⁸ COO ⁻
R ¹⁷ , R ¹⁸ : the same or different, alkylene groups having 1 to 4 carbon atoms.
provided that X ² is -R ¹⁷ SO ₃ ^- or -R ¹⁸ COO ^- when R ⁴ is an alkylene group having 1 to 4 carbon atoms, and R ⁴ is -Y ¹ -OPO ₃ ^- -Y ² When -, it is a hydrocarbon group having 1 or more and 4 or less carbon atoms.

R ¹ and R ² are preferably hydrogen atoms, respectively, from the viewpoints of availability of monomers, polymerizability of monomers, and reduction of LPD.

R ³ is preferably a hydrogen atom or a methyl group, more preferably a methyl group, from the viewpoints of availability of the monomer, polymerizability of the monomer, and LPD reduction.

X ¹ is preferably O (oxygen atom) from the viewpoint of availability of the monomer, polymerizability of the monomer, and reduction of LPD.

From the viewpoint of reducing LPD, R ⁴ is preferably an alkylene group having 2 or 3 carbon atoms or -Y ¹ -OPO ₃ ^- -Y ² -, and an alkylene group having 2 carbon atoms or -Y ¹ -OPO ₃ ^- -Y ² - is more preferred, and -Y ¹ -OPO ₃ ^- -Y ² - is even more preferred.

Y ¹ and Y ² are each preferably an alkylene group having 2 or 3 carbon atoms, more preferably an alkylene group having 2 carbon atoms, from the viewpoints of availability of the monomer, polymerizability of the monomer, and LPD reduction.

R ⁵ and R ⁶ are each preferably a methyl group or an ethyl group, more preferably a methyl group, from the viewpoints of monomer availability, monomer polymerizability, and LPD reduction.

X ² is -R ¹⁷ SO ₃ ^- or -R ¹⁸ COO ^- when R ⁴ is an alkylene group having 1 to 4 carbon atoms, and -R ¹⁸ COO ^- is preferred from the viewpoint of reducing LPD. X ² is a hydrocarbon group having 1 or more and 4 or less carbon atoms when R ⁴ is -Y ¹ -OPO ₃ ^- -Y ² -, and more preferably a methyl group from the viewpoint of reducing LPD.

The number of carbon atoms in R ¹⁷ is preferably 1 or more and 3 or less, more preferably 2 or more and 3 or less, from the viewpoints of availability of the monomer, polymerizability of the monomer, and LPD reduction. The number of carbon atoms in R ¹⁸ is preferably 1 or more and 3 or less, more preferably 1 or more and 2 or less, from the viewpoints of availability of the unsaturated monomer, polymerizability of the monomer, and reduction of LPD.

From the viewpoint of reducing LPD, the structural unit A is preferably a structural unit derived from at least one monomer selected from sulfobetaine methacrylate, methacryloyloxyethylphosphorylcholine (MPC), and carboxybetaine methacrylate, and methacryloyloxyethyl Structural units derived from at least one monomer selected from phosphorylcholine and carboxybetaine methacrylate are more preferred, and structural units derived from methacryloyloxyethylphosphorylcholine are even more preferred.

The water-soluble polymer a2 is a monomer containing a hydrophobic group, a monomer containing a hydroxyl group, a monomer containing an oxyalkylene group, a monomer containing an amino group, and a monomer containing a quaternary ammonium group. When it is a copolymer of at least one selected monomer (hereinafter sometimes abbreviated as "monomer B") and a monomer containing a betaine structure, derived from monomer B From the viewpoint of reducing LPD, the structural unit B of is preferably, for example, a structural unit B represented by the following formula (2).

However, in formula (2),
R ⁸ to R ¹⁰ : same or different, hydrogen atom, methyl group or ethyl group X ³ : O or NR ¹⁹
R ¹⁹ : a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms R ¹¹ : an alkylene group having 1 to 22 carbon atoms (wherein the hydrogen atom of the alkylene group may be substituted with a hydroxyl group) or - (AO) _m - (However, AO is an alkyleneoxy group having 2 to 4 carbon atoms, and m is an average addition mole number of 1 to 150.)
X ⁴ : hydrogen atom, hydrocarbon group having 1 to 4 carbon atoms (wherein the hydrogen atom of the hydrocarbon group may be substituted with a hydroxyl group), hydroxyl group, N ⁺ R ¹² R ¹³ R ¹⁴ or NR ¹⁵ R ¹⁶
R ¹² to R ¹⁶ : same or different, each represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms;

R ⁸ and R ⁹ are each preferably a hydrogen atom from the viewpoints of monomer availability, monomer polymerizability, and LPD reduction.

R ¹⁰ is preferably a hydrogen atom or a methyl group, more preferably a methyl group, from the viewpoints of availability of the monomer, polymerizability of the monomer, and LPD reduction.

X ³ is preferably O from the viewpoints of monomer availability, monomer polymerizability, and LPD reduction.

When X ⁴ is a hydrogen atom, the number of carbon atoms in the alkylene group of R ¹¹ is preferably 3 or more, more preferably 4 or more, from the viewpoints of availability of the monomer, polymerizability of the monomer, and reduction of LPD. 6 or more is more preferable, 18 or less is preferable, and 12 or less is more preferable, and m is preferably 2 or more and 30 or less from the same viewpoint.

When X ⁴ is a hydrocarbon group having 1 to 4 carbon atoms, R ¹¹ is preferably —(AO) _m — from the viewpoints of availability of the monomer, polymerizability of the monomer, and reduction of LPD, As for said m, 4 or more and 90 or less are preferable.

AO is an ethyleneoxy group (EO) which is an alkyleneoxy group having 2 carbon atoms and a propyleneoxy group which is an alkyleneoxy group having 3 carbon atoms, from the viewpoint of the availability of the monomer, the polymerizability of the monomer, and the reduction of LPD. It is preferably composed of one or more alkyleneoxy groups selected from groups (PO), and more preferably composed of EO. When —(AO) _m — contains two or more alkyleneoxy groups with different carbon numbers, the arrangement of the various alkyleneoxy groups may be either block or random, preferably block.

When X ⁴ is a hydroxyl group, N ⁺ R ¹² R ¹³ R ¹⁴ or NR ¹⁵ R ¹⁶ , R ¹¹ has 1 or more carbon atoms from the viewpoint of availability of the monomer, polymerizability of the monomer, and reduction of LPD. An alkylene group of 22 or less (wherein the hydrogen atom of the hydrocarbon group may be substituted with a hydroxyl group) is preferable, and the number of carbon atoms in the alkylene group is preferably 2 or more, and 3 or less from the same viewpoint. Preferred, and 2 is more preferred.

X ⁴ is preferably a hydrogen atom, a methyl group, a hydroxyl group, or N ⁺ R ¹² R ¹³ R ¹⁴ from the viewpoints of monomer availability, monomer polymerizability and LPD reduction, and R ¹² to R ¹⁴ are , respectively, from the same viewpoint, a methyl group or an ethyl group is preferable, and a methyl group is more preferable.

As the structural unit B, a hydrophobic group such as alkyl methacrylate (a hydrogen atom of the hydrophobic group may be substituted with a hydroxyl group) from the viewpoint of availability of the monomer, polymerizability of the monomer, and reduction of LPD. at least one selected from unsaturated monomers having a A structural unit derived from a monomer is preferable, and a structural unit derived from an unsaturated monomer having a hydrophobic group such as alkyl methacrylate (the hydrogen atom of the hydrophobic group may be substituted with a hydroxyl group) is more preferable. .

Structural unit B includes butyl methacrylate (BMA), 2-ethylhexyl methacrylate (EHMA), lauryl methacrylate (LMA), stearyl methacrylate (SMA), methacryloyloxyethyldimethylethylaminium (MOEDES), and 2-hydroxy-3 methacrylate. - (trimethylamino)propyl (THMPA), methacryloylethyltrimethylaminium (MOETMA), methoxypolyethyleneglycol methacrylate (MPEGMA), polyethyleneglycol methacrylate (PEGMA), methoxypolypropyleneglycol methacrylate (MPPGMA), polypropyleneglycol methacrylate (PPGMA) and Structural units derived from at least one monomer selected from hydroxyethyl methacrylate (HEMA) are more preferred, and structural units derived from at least one monomer selected from BMA and LMA are more preferred.

(Molar ratio of structural unit A and structural unit B)
From the viewpoint of reducing LPD, the molar ratio of structural unit A and structural unit B in water-soluble polymer a2 (structural unit A/structural unit B) is preferably 10/90 or more, more preferably 20/80 or more, and further It is preferably 30/70 or more, and from the same viewpoint, preferably 98/2 or less, more preferably 95/5 or less.

(Structural Units Other than Structural Unit A and Structural Unit B)
The water-soluble polymer a2 may contain structural units other than the structural unit A and the structural unit B as long as the effects of the present invention are not impaired. Structural units other than structural unit A and structural unit B are preferably structural units derived from hydrophobic unsaturated monomers such as styrene.

The content of structural units other than structural unit A and structural unit B in water-soluble polymer a2 is preferably 1% by mass or less, more preferably 0.5% by mass or less, still more preferably 0.1% by mass or less, Even more preferably, it is 0.05% by mass or less. The content of structural units other than the structural unit A and the structural unit B in the water-soluble polymer a2 may be 0% by mass.

The total content of the structural unit A and the structural unit B in the water-soluble polymer a2 is preferably 99% by mass or more, more preferably 99.5% by mass or more, still more preferably 99.9% by mass or more, and still more It is preferably 99.95% by mass or more, and may be 100% by mass.

From the viewpoint of reducing LPD, the weight average molecular weight of the water-soluble polymer a2 is preferably 10,000 or more, more preferably 3,000 or more, still more preferably 5,000 or more, and even more preferably 10,000 or more. , more preferably 30,000 or more, and from the viewpoint of improving the solubility of the water-soluble polymer a2 and reducing LPD, it is preferably 1,500,000 or less, more preferably 1,200,000 or less, and even more preferably 1,000,000 or less.

From the viewpoint of reducing LPD, the content of the water-soluble polymer a2 in the rinse agent composition of the present invention is preferably 0.00001% by mass or more, more preferably 0.00005% by mass or more, and 0.0001% by mass or more. is more preferable, and from the viewpoint of reducing LPD, it is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less.

In the rinse agent composition of the present invention, the mass ratio of water-soluble polymer a1 to water-soluble polymer a2 (water-soluble polymer a1/water-soluble polymer a2) is preferably 0.5 or more from the viewpoint of reducing LPD. It is preferably 1 or more, more preferably 2 or more, and from the viewpoint of reducing LPD, it is preferably 500 or less, more preferably 200 or less, and even more preferably 100 or less.

[Aqueous medium]
Examples of the aqueous medium contained in the rinse agent composition of the present invention include water such as ion-exchanged water and ultrapure water, and a mixed medium of water and a solvent. Examples of the solvent include polyhydric alcohols having 2 to 4 carbon atoms, preferably glycerin or propylene glycol. The water in the aqueous medium is preferably ion-exchanged water or ultrapure water, more preferably ultrapure water. When the aqueous medium is a mixed medium of water and a solvent, the ratio of water to the entire mixed medium is preferably 90% by mass or more, more preferably 92% by mass or more, more preferably 95% by mass or more, from the viewpoint of economy. preferable.

The content of the aqueous medium in the rinse agent composition of the present invention is preferably the remainder of the water-soluble polymer A, the below-described basic compound added as necessary, and other optional components described below.

[Optional component (auxiliary agent)]
The rinse agent composition of the present invention may further contain a pH adjuster, preservative, alcohol, chelating agent, anionic surfactant, and nonionic surfactant, as long as the effects of the present invention are not hindered. may include at least one optional ingredient.

[pH adjuster]
Examples of pH adjusters include basic compounds, acidic compounds, salts thereof, and the like. The salt of the acidic compound is preferably at least one salt selected from alkali metal salts, ammonium salts and amine salts, and more preferably an ammonium salt. When the basic compound takes the form of a salt, the counter ion is preferably at least one selected from hydroxide ion, chloride ion and iodide ion, more preferably hydroxide ion and chloride ion. is at least one selected from

(basic compound)
Basic compounds include, for example, sodium hydroxide, potassium hydroxide, ammonia, ammonium hydroxide, ammonium carbonate, ammonium hydrogen carbonate, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, monoethanolamine, diethanolamine, tri ethanolamine, N-methylethanolamine, N-methyl-N,N-diethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N,N-dibutylethanolamine, N-(β- aminoethyl)ethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, ethylenediamine, hexamethylenediamine, piperazine hexahydrate, anhydrous piperazine, 1-(2-aminoethyl)piperazine, N-methylpiperazine, Diethylenetriamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide. Two or more kinds of these basic compounds may be used. Ammonia is more preferred as the basic compound from the viewpoint of achieving both reduction of silicon wafer haze and reduction of LPD, and from the viewpoint of improving the storage stability of the rinse agent composition.

(acidic compound)
Examples of acidic compounds include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid, and organic acids such as acetic acid, oxalic acid, succinic acid, glycolic acid, malic acid, citric acid and benzoic acid.

[Preservative]
Preservatives include phenoxyethanol, benzalkonium chloride, benzethonium chloride, 1,2-benzisothiazolin-3-one, (5-chloro-)2-methyl-4-isothiazolin-3-one, hydrogen peroxide, or chlorite and the like.

[Alcohol]
Alcohols include methanol, ethanol, propanol, butanol, isopropyl alcohol, 2-methyl-2-propanol, ethylene glycol, propylene glycol, polyethylene glycol, glycerin and the like. The alcohol content in the rinse agent composition of the present invention is preferably 0.01% by mass to 10% by mass.

[Chelating agent]
Chelating agents include 1-hydroxyethane 1,1-diphosphonic acid, ethylenediaminetetraacetic acid, sodium ethylenediaminetetraacetate, nitrilotriacetic acid, sodium nitrilotriacetate, ammonium nitrilotriacetic acid, hydroxyethylethylenediaminetriacetic acid, hydroxyethylethylenediaminetriacetic acid. sodium, triethylenetetraminehexaacetic acid, sodium triethylenetetraminehexaacetate, and the like. The content of the chelating agent in the rinse agent composition of the present invention is preferably 0.001 to 10% by mass.

[Anionic surfactant]
Examples of anionic surfactants include fatty acid soaps, carboxylates such as alkyl ether carboxylates, sulfonates such as alkylbenzene sulfonates and alkylnaphthalene sulfonates, higher alcohol sulfates, and alkyl ether sulfates. and phosphate ester salts such as alkyl phosphate esters.

[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 alkylphenyl ether, poly Polyethylene glycol types such as oxyalkylene (hardened) castor oil, polyhydric alcohol types such as sucrose fatty acid esters and alkyl glycosides, fatty acid alkanolamides, and the like can be mentioned.

The pH of the rinse agent composition of the present invention at 25° C. is preferably 2 or more, more preferably 2.5 or more, and further preferably 3.0 or more, from the viewpoint of reducing LPD and improving the storage stability of the rinse agent composition. From the same viewpoint, it is preferably 12 or less, more preferably 11.5 or less, and even more preferably 11.0 or less. Adjustment of pH can be performed by adding a pH adjuster as necessary. Here, the pH at 25° C. can be measured using a pH meter (HM-30G, manufactured by Toa Denpa Kogyo Co., Ltd.), and is the value one minute after the electrode is immersed in the rinse agent composition.

[Method for producing rinse agent composition]
The rinse agent composition of the present invention can be produced, for example, by a production method including a step of blending the water-soluble polymer A, the aqueous medium, and optional ingredients by a known method. In the present application, "blending" includes mixing the water-soluble polymer A and, if necessary, optional components with an aqueous medium simultaneously or sequentially. There are no restrictions on the mixing order of each component.

The blending can be performed using a mixer such as a homomixer, a homogenizer, an ultrasonic disperser, and a wet ball mill. The blending amount of each component in the method for producing the rinse agent composition of the present embodiment can be the same as the content of each component of the rinse agent composition described above.

A preferred example of the method for manufacturing a semiconductor substrate of the present invention includes a polishing step of polishing a silicon wafer to be polished using a polishing liquid composition containing silica particles, a water-soluble polymer B, a nitrogen-containing basic compound, and an aqueous medium;
a rinsing step of rinsing the polished silicon wafer with a rinsing agent composition containing a water-soluble polymer A and an aqueous medium;
and a cleaning step of cleaning the rinsed silicon wafer, wherein the water-soluble polymer B is at least one selected from polyglycerin, polyglycerin alkyl ether, polyacrylamide, sulfonic acid-modified polyvinyl alcohol, and polyvinyl methyl ether. It is a water-soluble polymer, and the weight average molecular weight of the water-soluble polymer B is 1000 or more and 1 million or less,
The water-soluble polymer A contains both at least one water-soluble polymer a3 selected from polyglycerin and polyglycerin alkyl ether and a water-soluble polymer a2 containing a betaine structure, or polyglycerin and polyglycerin alkyl ether. and wherein the water-soluble polymer a3 has a weight average molecular weight of 500 or more and 30,000 or less, and the water-soluble polymer a2 has a weight average molecular weight of 30,000 or more and 1,000,000 or less. .

1. Method for measuring various parameters (1) Method for measuring zeta potential of aqueous dispersions S ₀ , S, s ₀ , s The aqueous dispersions were placed in a capillary cell DTS1070 and measured using Malvern's "Zetasizer Nano ZS". , the zeta potential was measured under the following conditions.
Sample: Refractive index: 1.450 Absorptance: 0.010
Dispersion medium: viscosity: 0.8872 cP, refractive index: 1.330, dielectric constant: 78.5
Temperature: 25°C

(1-1) Preparation of Silica Aqueous Dispersion (Aqueous Dispersion S ₀ ) Ion-exchanged water was added to a silica particle undiluted solution (“PL-3” manufactured by Fuso Chemical Co., Ltd.), and then the pH at 25° C. An aqueous hydrochloric acid solution or an aqueous ammonia solution was added so as to adjust the concentration to 7.0 to obtain an aqueous dispersion S ₀ having a silica particle concentration of 0.1% by mass.

(1-2) Preparation of Water-Soluble Polymer-Containing Silica Aqueous Dispersion (Aqueous Dispersion S) In ion-exchanged water, each water-soluble polymer A or its comparative object, then silica particle undiluted solution (Fuso Chemical Co., Ltd. “PL -3") was added. After that, an aqueous hydrochloric acid solution or an aqueous ammonia solution is added to this so that the pH at 25 ° C. becomes 7.0, and the concentration of the water-soluble polymer A or its comparison object is 0.1% by mass, and the silica particles An aqueous dispersion S having a concentration of 0.1% by mass was obtained.

(2-1) Preparation of aqueous silica dispersion (aqueous dispersion s ₀ ) Ion-exchanged water was added to a silica particle undiluted solution (“PL-3” manufactured by Fuso Chemical Co., Ltd.), and then the pH at 25°C was adjusted to An aqueous solution of hydrochloric acid or an aqueous solution of ammonia was added so that the concentration became 10.0 to obtain an aqueous dispersion s ₀ having a silica particle concentration of 0.1% by mass.

(2-2) Preparation of Water-Soluble Polymer-Containing Silica Water Dispersion (Water Dispersion s) In ion-exchanged water, each water-soluble polymer B or its comparative object, and then silica particle stock solution (manufactured by Fuso Chemical Co., Ltd. “PL -3") was added. After that, an aqueous hydrochloric acid solution or an aqueous ammonia solution is added to this so that the pH at 25 ° C. becomes 10.0, and the concentration of the water-soluble polymer B or its comparison object is 0.01% by mass. An aqueous dispersion s having a concentration of 0.1% by mass was obtained.

(2) Method for measuring secondary particle size of silica particles Silica water dispersions S ₀ , S, s ₀ , s are placed in a Disposable Sizing Cuvette (polystyrene 10 mm cell) up to a height of 10 mm from the bottom, and placed in a Malvern Measured by the dynamic light scattering method using "Zetasizer Nano ZS", the value of the Z average particle size is the secondary particle size _d0 , d, D of silica water dispersion _S0 , S, _s0 , s ₀ and D. Measurement conditions are described below.
Sample: refractive index: 1.450, absorption: 0.010
Dispersion medium: viscosity: 0.8872 cP, refractive index: 1.330
Temperature: 25°C

(3) Measurement of weight-average molecular weight of water-soluble polymer The weight average molecular weight of the comparative substance was calculated based on the peaks in the chromatogram obtained by applying the gel permeation chromatography (GPC) method under the following conditions.
Apparatus: HLC-8320 GPC (Tosoh Corporation, detector integrated type)
Column: GMPWXL + GMPWXL (anion)
Eluent: 0.2M phosphate buffer/CH ₃ CN=9/1
Flow rate: 0.5mL/min
Column temperature: 40°C
Detector: RI Detector standard substance: Monodisperse polyethylene glycol with known weight average molecular weight

2. Preparation of rinse agent composition Water-soluble polymer A shown in Table 2 or its comparative substance and ion-exchanged water are stirred and mixed, and if necessary, hydrochloric acid aqueous solution or 28% by mass ammonia water (Kishida Chemical Co., Ltd. reagent) Special grade) was used to adjust the pH at 25° C. to 7.0 to obtain rinse agent compositions of Examples 1 to 16 and Comparative Examples 1 and 2. However, the rinse agent composition of Example 5 contained 0.04% by mass of polyglycerin (40-mer) and 0.01% by mass of polyglycerin alkyl ether, and the rinse agent compositions of Examples 6 to 8 contained poly Contains 0.049% by mass of glycerin alkyl ether and 0.001% by mass of a water-soluble polymer having a betaine structure.

The details of the water-soluble polymer A and the water-soluble polymer B used in the preparation of the rinse agent compositions and abrasive compositions of Examples 1 to 16 and Comparative Examples 1 and 2, and their comparative objects are given below. Street.
[Water-soluble polymer A and its comparative object]
A1: PGL XPW (polyglycerin 40-mer): manufactured by Daicel A2: Sermolis B044 (polyglycerin 20-mer lauryl ether): manufactured by Daicel A3: Lipidure-HM (Mw 100,000, MPC homopolymer): NOF Corporation Product A4: Lipidure-PMB (Mw 600,000, copolymer of MPC and BMA, molar ratio (MPC/BMA) = (80: 20): manufactured by NOF Corporation)
A5: MPC/LMA (Mw 100,000, copolymer of MPC and LMA, molar ratio (MPC/LMA) = (80:20)): Kao A11: SE400 (Mw 250000): Daicel A12: Kollicoat IR (Mw 26,500): manufactured by BASF

[Water-soluble polymer B and its comparative object]
B1: Sermolis B044 (polyglycerin 20-mer lauryl ether): Daicel B2: PGL XPW (polyglycerin 40-mer): Daicel B3: Polyacrylamide (Mw 600,000 to 1,000,000): Polysciences Manufactured B4: Gohselan L-3266 (Mw 23,000): Nippon Synthetic Chemical Industry Co., Ltd. B5: Polyvinyl methyl ether (PVME, Mw 80,000): Tokyo Chemical Industry Co., Ltd. B11: SE400 (Mw 250,000): Daicel B12 : Kollicoat IR (Mw26, 500): manufactured by BASF

Details of each structural unit of the water-soluble polymers A3 to A5 are as shown in Table 1 below.

A method for synthesizing the water-soluble polymer A5 is as follows.

[Water-soluble polymer A5]
10.0 g of ethanol was put into a 300 mL four-necked flask, and the temperature was raised to 70°C. A solution obtained by mixing 5.0 g of MPC (manufactured by Tokyo Chemical Industry Co., Ltd.), 1.1 g of LMA (manufactured by Wako Pure Chemical Industries, Ltd.), and 10.0 g of ethanol, and 2,2′-azobis A solution obtained by mixing 0.021 g of (isobutyronitrile) (manufactured by Wako Pure Chemical Industries, Ltd.) and 4.4 g of ethanol was separately added dropwise over 2 hours for polymerization. After aging for 6 hours, the solvent was distilled off under reduced pressure and replaced with water to obtain an aqueous polymer solution containing water-soluble polymer A5 (copolymer of MPC and LMA). The molar ratio (MPC/LMA) of the constituent units in the water-soluble polymer A5 was 80/20, and the weight average molecular weight of the water-soluble polymer A5 was 100,000.

3. Polishing process [Abrasive composition used for final polishing]
The compositions of the polishing compositions used in Examples 1 to 16 and Comparative Examples 1 and 2 shown in Table 2 are as follows.
Silica particles (PL-3, average primary particle size 35 nm, average secondary particle size 69 nm, degree of association 2.0): 0.17% by mass
Water-soluble polymer B or its comparative object: 0.01% by mass
Ammonia: 0.01% by mass
PEG (weight average molecular weight 6000); 0.0008% by mass
pH (25°C): 10.2±0.4

[Final polishing conditions]
Polishing machine: Single-sided 8-inch polishing machine manufactured by Okamoto Co., Ltd. “GRIND-X SPP600s”
Polishing pad: Suede pad manufactured by Toray Coatex Co., Ltd. (Asker hardness: 64, thickness: 1.37 mm, nap length: 450 μm, opening diameter: 60 μm)
Silicon wafer polishing pressure: 100 g/cm ²
Surface plate rotation speed: 60 rpm
Polishing time: 5 minutes Supply rate of abrasive composition: 150 g/minute Temperature of abrasive composition: 23°C
Carrier rotation speed: 60 rpm

4. Rinse step The rinse agent composition is filtered with a filter (compact cartridge filter "MCP-LX-C10S" manufactured by Advantech Co., Ltd.) immediately before the start of the rinse treatment, and the following silicon wafer (diameter 200 mm) is filtered under the following rinse conditions. A silicon single-sided mirror wafer (conductivity type: P, crystal orientation: 100, resistivity of 0.1 Ω·cm or more and less than 100 Ω·cm)) was rinsed. Prior to the rinsing treatment, the silicon wafer was preliminarily rough-polished using a commercially available abrasive composition. The haze of the silicon wafer that had undergone rough polishing and was subjected to final polishing was 2.680 (ppm). Haze is a value in a dark field wide oblique incidence channel (DWO) measured using a KLA Tencor "Surfscan SP1-DLS". Thereafter, final polishing was performed under the above conditions, and immediately after that, rinsing was performed using each rinse agent composition under the following conditions.

[Rinse conditions]
Polishing machine: Single-sided 8-inch polishing machine manufactured by Okamoto Co., Ltd. “GRIND-X SPP600s”
Polishing pad: Suede pad manufactured by Toray Coatex Co., Ltd. (Asker hardness: 64, thickness: 1.37 mm, nap length: 450 μm, opening diameter: 60 μm)
Silicon wafer rinse pressure: 60 g/cm ²
Surface plate rotation speed: 30 rpm
Rinse time: 10 seconds Supply rate of rinse agent composition: 1000 mL/min Temperature of rinse agent composition: 23°C
Carrier rotation speed: 30 rpm

5. Cleaning Process After the rinsing process, the silicon wafer was subjected to ozone cleaning and dilute hydrofluoric acid cleaning as follows. In the ozone cleaning, an aqueous solution containing 20 ppm of ozone was sprayed from a nozzle at a flow rate of 1 L/min toward the center of the silicon wafer rotating at 600 rpm for 3 minutes. At this time, the temperature of the ozone water was normal temperature. Next, dilute hydrofluoric acid cleaning was performed. In dilute hydrofluoric acid cleaning, an aqueous solution containing 0.5% by mass of ammonium hydrogen fluoride (special grade: Nacalai Techs Co., Ltd.) is sprayed from a nozzle toward the center of a silicon wafer rotating at 600 rpm at a flow rate of 1 L/min for 5 seconds. did. 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. Spin drying rotated the silicon wafer at 1500 rpm.

6. Evaluation of LPD of Silicon Wafer For evaluation of LPD on the surface of the silicon wafer after cleaning, a surface roughness measuring device “Surfscan SP1-DLS” (manufactured by KLA Tencor) was used, and the particle size on the surface of the silicon wafer was 45 nm or more. was evaluated by measuring the number of particles in the As for the LPD evaluation results, the smaller the numerical value, the smaller the number of surface defects. Each LPD measurement was performed on two silicon wafers, and the average values are shown in Table 2.

As shown in Table 2, in Examples 1 to 16, in which the polishing liquid composition containing the water-soluble polymer B was used in the polishing step, and the rinse agent composition containing the water-soluble polymer A was used in the rinsing step, comparative LPD reduction was better than in Examples 1 and 2.

According to the silicon wafer manufacturing method of the present invention, since LPD can be reduced, it is useful in manufacturing semiconductor substrates such as silicon wafers, contributing to improvement in productivity and cost reduction.

Claims (16)

a polishing step of polishing a silicon wafer to be polished using a polishing liquid composition containing silica particles, a water-soluble polymer B, a nitrogen-containing basic compound, and an aqueous medium;
a rinsing step of rinsing the polished silicon wafer with a rinsing agent composition containing a water-soluble polymer A and an aqueous medium;
and a cleaning step of cleaning the rinsed silicon wafer, wherein the water-soluble polymer B is
It consists of the water-soluble polymer B, silica particles, water, and hydrochloric acid or ammonia added as necessary so that the pH at 25° C. is 10.0, and the concentration of the water-soluble polymer B is 0.01. % by mass, the concentration of the silica particles is 0.1% by mass, the zeta potential z of the water-soluble polymer-containing aqueous silica dispersion (aqueous dispersion s) having a pH of 10.0 at 25° C., and the silica particles and water A silica water dispersion containing hydrochloric acid or ammonia added as necessary so that the pH at 25°C is 10.0, the concentration of the silica particles being 0.1% by mass, and the pH at 25°C being 10.0. A water-soluble polymer having a difference (zz ₀ ) between the liquid (aqueous dispersion s ₀ ) and the zeta potential z ₀ of less than 15 mV,
The water-soluble polymer A is
It consists of the water-soluble polymer A, silica particles, water, and hydrochloric acid or ammonia added as necessary so that the pH at 25° C. is 7.0, and the concentration of the water-soluble polymer A is 0.1. % by mass, the concentration of the silica particles is 0.1% by mass, the zeta potential Z of the water-soluble polymer-containing aqueous silica dispersion (aqueous dispersion S) having a pH of 7.0 at 25° C., and the silica particles and water Hydrochloric acid or ammonia added as necessary so that the pH at 25°C is 7.0, and the silica water has a concentration of the silica particles of 0.1% by mass and a pH of 7.0 at 25°C. A method for producing a silicon wafer, wherein the water-soluble polymer is such that the difference (ZZ ₀ ) between the zeta potential Z ₀ of the dispersion (aqueous dispersion S ₀ ) is 25 mV or less. 2. The method of manufacturing a silicon wafer according to claim 1, wherein said difference (ZZ ₀ ) is smaller than said difference (zz ₀ ). 3. The method for producing a silicon wafer according to claim 1, wherein the water-soluble polymer A contains at least one water-soluble polymer a1 selected from polyglycerin, polyglycerin derivatives, polyglycidol, and polyglycidol derivatives. . The water-soluble polymer A contains both at least one water-soluble polymer a1 selected from polyglycerin, polyglycerin derivatives, polyglycidol, and polyglycidol derivatives, and a water-soluble polymer a2 containing a betaine structure, The method for manufacturing a silicon wafer according to claim 1 or 2. 5. The method for producing a silicon wafer according to claim 3, wherein the polyglycerin derivative is an alkyl ether of polyglycerin. 5. The method for producing a silicon wafer according to claim 3, wherein said water-soluble polymer A contains both polyglycerin and alkyl ether of polyglycerin. The method for producing a silicon wafer according to claim 3 or 4, wherein the water-soluble polymer a1 has a weight average molecular weight of 500 or more and 1,500,000 or less. 5. The method for producing a silicon wafer according to claim 4, wherein the water-soluble polymer a2 has a weight average molecular weight of 01,000 or more and 1,500,000 or less. Claims 1 to 7, wherein the water-soluble polymer B is at least one selected from the group consisting of polyglycerin, polyglycerin derivatives, polyglycidol, polyglycidol derivatives, polyacrylamide, polyvinyl alcohol derivatives, and polyvinyl alkyl ethers. The method for producing a silicon wafer according to any one of items 1 to 1. The method for producing a silicon wafer according to any one of claims 1 to 9, wherein the water-soluble polymer B has a weight average molecular weight of 1,000 or more and 5,000,000 or less. The method for producing a silicon wafer according to any one of claims 1 to 10, wherein the rinse agent composition further contains a basic compound. 12. The silicon wafer production according to any one of claims 1 to 11, wherein the content of the water-soluble polymer B in the polishing composition is 0.001% by mass or more and 1.0% by mass or less. Method. The silicon wafer production according to any one of claims 1 to 12, wherein the content of the water-soluble polymer A in the rinse agent composition is 0.001% by mass or more and 1.0% by mass or less. Method. 14. The method of manufacturing a silicon wafer according to any one of claims 1 to 13, wherein in said rinsing step, a water rinsing treatment using water as a rinsing liquid is performed before said rinsing treatment. 15. The method for manufacturing a silicon wafer according to claim 1, wherein the rinsing process in the rinsing process is performed using a polishing apparatus used in the polishing process. A method for manufacturing a semiconductor substrate, comprising a step of manufacturing a silicon wafer by the method for manufacturing a silicon wafer according to any one of claims 1 to 15.