JP2022096448A - Rinsing agent composition for silicon wafer - Google Patents

Abstract

To provide a rinsing agent composition capable of reducing LPD on a polished silicon wafer surface.SOLUTION: A rinsing agent composition is used for rinsing the surface of a polished silicon wafer containing component A and component B: the component A being alkyl polyglucoside with an average degree of condensation of 1.9 or higher; and the component B being water.SELECTED DRAWING: None

Description

The present disclosure relates to a rinsing agent composition used for rinsing the surface of a polished silicon wafer, and a rinsing method and a method for manufacturing a semiconductor substrate using the rinsing agent composition.

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 shallower in photolithography performed in the manufacturing process of semiconductor devices, and the demand for reducing surface defects (LPD: Light point defects) and surface roughness (Haze) of silicon wafers (bare wafers) is becoming more stringent. It has become.

For the purpose of improving the quality of silicon wafers, the polishing process for polishing silicon wafers includes a wrapping (rough polishing) process for flattening the silicon wafer obtained by slicing a silicon single crystal ingot into thin disks. After etching the wrapped silicon wafer, there is a finish polishing process in which the surface of the silicon wafer is mirror-polished. In particular, the finish polishing process performed at the final stage of polishing is performed for the purpose of suppressing Haze and reducing LPD of particles, scratches, pits, etc. by improving the wettability (hydrophilization) of the polished silicon wafer surface. ..

For example, Patent Document 1 and Patent Document 2 describe an amphipathic polymer such as hydroxyethyl cellulose (HEC) and cationized polyvinyl alcohol (PVA) and an alkyl polyglucoside (AG) for the purpose of reducing surface roughness and LPD. ) Is proposed.
Further, Patent Document 3 proposes a cleaning agent for dipping a silicon wafer for a solar cell using an alkylpolyglucoside (AG) for the purpose of reducing the residue on the surface of the substrate.

Japanese Unexamined Patent Publication No. 2013-105954 Japanese Unexamined Patent Publication No. 2017-155198 Japanese Unexamined Patent Publication No. 2012-248738

However, in the polishing liquid compositions proposed in Patent Documents 1 and 2, the reduction of LPD is not sufficient because silica adheres to the surface of the silicon wafer due to the amphipathic polymer. Further, when the alkyl polyglucoside (AG) having an average degree of condensation of 1.3-1.7 used in the examples of Patent Document 1 is used for rinsing a silicon wafer for semiconductors, the wettability of the silicon wafer surface becomes high. It is reduced and the reduction of LPD is not sufficient.
Patent Document 3 does not describe the use of alkyl polyglucoside (AG) in the rinsing process of silicon wafers for semiconductors. Further, when the alkyl polyglucoside (AG) having an average condensation degree of 1.2 and 1.8 used in the examples of the same document is used for rinsing a silicon wafer for semiconductor, the reduction of LPD is not sufficient.

Therefore, the present disclosure provides a rinsing agent composition capable of reducing LPD on a polished silicon wafer surface, a rinsing method using the rinsing agent composition, and a method for manufacturing a semiconductor substrate.

The present disclosure relates, in one aspect, to a rinsing agent composition used for rinsing the surface of a polished silicon wafer containing the following component A and the following component B.
Component A: Alkyl polyglucoside with an average degree of condensation of 1.9 or more Component B: Water

The present disclosure relates to a method for rinsing a silicon wafer, which comprises, in one aspect, a step of rinsing a polished silicon wafer with the rinsing agent composition of the present disclosure.

The present disclosure relates to a method for manufacturing a semiconductor substrate, which comprises the following steps (1), (2), and (3) in one embodiment.
(1) A step of polishing a silicon wafer to be polished using a polishing liquid composition containing abrasive grains.
(2) A step of rinsing the silicon wafer polished in the step (1) using the rinsing agent composition of the present disclosure.
(3) A step of cleaning the silicon wafer rinsed in the step (2).

According to the present disclosure, it is possible to provide a rinsing agent composition capable of reducing LPD on the surface of a polished silicon wafer, a rinsing method using the rinsing agent composition, and a method for manufacturing a semiconductor substrate.

The present disclosure is based on the finding that by rinsing the surface of a polished silicon wafer with an alkyl polyglucoside having a specific degree of condensation, the wettability of the wafer surface can be improved and LPD can be reduced.

That is, the present disclosure, in one embodiment, is a rinsing agent composition used for rinsing the surface of a polished silicon wafer containing the following component A and the following component B (hereinafter, "rinsing agent of the present disclosure"). Also referred to as "composition").
Component A: Alkyl polyglucoside with an average degree of condensation of 1.9 or more Component B: Water

According to the present disclosure, in one or more embodiments, the LPD on the surface of a polished silicon wafer can be reduced.

The details of the mechanism of effect manifestation of the present disclosure are not clear, but it is inferred as follows.
It is known that cleaning with a surfactant having a hydrophobic group and a hydrophilic group is effective for removing abrasive grains such as organic substances and silica particles adsorbed on the surface of a hydrophobic silicon wafer. However, if the hydrophilic group of the surfactant is short, the wettability of the wafer surface after rinsing will be poor, and if water is repelled, silica particles will easily adhere to the silicon wafer surface, and recontamination will occur at the interface of the silicon wafer. Be done.
On the other hand, in the rinsing step using the rinsing agent composition of the present disclosure, the surface of the silicon wafer is modified to a sufficiently hydrophilic surface by an alkyl polyglucoside (component A) having a specific degree of condensation. It is presumed that the number of silica particles remaining on the surface is reduced.
Therefore, it is presumed that the residual amount of silica particles on the silicon wafer after polishing used in the cleaning step can be remarkably reduced, and the LPD of the silicon wafer can be reduced.
However, the present disclosure may not be construed as being limited to these mechanisms.

[Alkyl polyglucoside (component A)]
The alkyl polyglucoside (hereinafter, also referred to as “component A”) contained in the rinsing agent composition of the present disclosure is an alkyl polyglucoside having an average condensation degree of 1.9 or more. The component A may be one kind or a combination of two or more kinds. The component A preferably includes, in one or more embodiments, a compound represented by the following general formula (I).
R-Gy (I)
However, in the formula (I), R indicates an alkyl group having 8 to 18 carbon atoms, G indicates a residue derived from a sugar, and y indicates the average degree of condensation of the sugar, which is a number of 1.9 or more and 5 or less. Is.

In the above formula (I), R is an alkyl group having 8 to 18 carbon atoms from the viewpoint of reducing LPD. The number of carbon atoms of the alkyl group is preferably 8 or more, more preferably 10 or more, more preferably 18 or less, more preferably 16 or less, still more preferably 14 or less, from the viewpoint of reducing LPD. , 12 or less is more preferable, and 10 or less is further preferable. Therefore, the number of carbon atoms of the alkyl group is preferably 8 to 16, more preferably 8 to 14, and even more preferably 10 to 12 from the viewpoint of reducing LPD and improving wettability. R may be a straight chain or a branched chain.

In the above formula (I), G is a residue derived from sugar from the viewpoint of reducing LPD, and examples thereof include residues derived from glucose. The average degree of condensation y is 1.9 or more, preferably 2 or more, more preferably 2.1 or more, still more preferably 2.2 or more, still more preferably 2.3 or more, from the viewpoint of reducing LPD. 2.4 or more is more preferable, 2.5 or more is further preferable, 2.6 or more is further preferable, 2.7 or more is further preferable, and 5 or less, 4 or less is preferable, and 3.5 or less is preferable. More preferably, 3.4 or less is further preferable, 3.3 or less is further preferable, 3.2 or less is further preferable, 3.1 or less is further preferable, and 3.0 or less is further preferable. The average degree of condensation is the average value of residues derived from sugar, and can be measured by nuclear magnetic resonance spectroscopy (NMR). Specifically, it can be measured by the method described in Examples.

The component A can be produced, for example, by reacting a sugar with an excess alcohol in the presence of an acidic catalyst and distilling off the unreacted alcohol from the reaction solution after the reaction. For example, after reacting a sugar with an excess alcohol in the presence of an acidic catalyst, an inorganic acid salt is added to a reaction solution containing an alkylpolyglycoside and an unreacted alcohol, and then the unreacted alcohol is distilled off. It can be manufactured by the method of leaving.

The proportion of the alkyl glycoside having a degree of condensation of 1 contained in the component A is preferably 10% or more, more preferably 20% or more, still more preferably 30% or more, still more preferably 30% or more, from the viewpoint of reducing LPD and wettability. It is 40% or more, and preferably 70% or less, more preferably 60% or less, still more preferably 50% or less. The method for measuring the alkyl glycoside having a degree of condensation of 1 can be measured by NMR in the same manner as the above-mentioned average degree of condensation.

The content of component A in the rinse agent composition of the present disclosure is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, still more preferably 0, from the viewpoint of improving wettability and reducing LPD. It is 0.05% by mass or more, and from the same viewpoint, it is preferably 1% by mass or less, more preferably 0.5% by mass or less, still more preferably 0.1% by mass or less. When the component A is a combination of two or more kinds, the content of the component A means the total content thereof. In the present disclosure, 1% by mass is 10,000% by mass.

[Water (component B)]
The rinse agent composition of the present disclosure contains water (hereinafter, also referred to as "component B") as a medium. Examples of the component B include distilled water, ion-exchanged water, pure water, ultrapure water and the like. The content of component B in the rinsing agent composition of the present disclosure can be a residue excluding component A and optional components described later.

[Arbitrary ingredient (auxiliary agent)]
The rinse composition of the present disclosure is selected from pH adjusters, preservatives, alcohols, chelating agents, anionic surfactants, nonionic surfactants, and oxidizing agents to the extent that the effects of the present disclosure are not impaired. Can further comprise at least one optional ingredient.

<pH adjuster>
Examples of the pH adjuster include basic compounds, acidic compounds, salts thereof and the like. The salt of the acidic compound is preferably at least one selected from an alkali metal salt, an ammonium salt, and an amine salt, 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, and more preferably hydroxide ion and chloride ion. At least one selected from.

(Basic compound)
Examples of the basic compound include sodium hydroxide, potassium hydroxide, ammonia, ammonium hydroxide, ammonium carbonate, ammonium hydrogencarbonate, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, monoethanolamine, diethanolamine and tri. Ethanolamine, N-methylethanolamine, N-methyl-N, N-dietanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, N, N-dibutylethanolamine, N- (β-) Aminoethyl) ethaneolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, ethylenediamine, hexamethylenediamine, piperazine / hexahydrate, anhydrous piperazine, 1- (2-aminoethyl) piperazine, N-methylpiperazine, Examples thereof include diethylenetriamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide and tetrabutylammonium hydroxide. Two or more of these basic compounds may be used. As the basic compound, ammonia is more preferable from the viewpoint of achieving both reduction of Haze and reduction of LPD of the silicon wafer and improvement of storage stability of the rinsing agent assembly.

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

<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 in the rinse agent composition of the present invention is preferably 0.01% by mass to 10% by mass.

<Chelating agent>
Chelating agents include ethylenediamine tetraacetic acid, sodium ethylenediaminetetraacetate, nitrilotriacetic acid, sodium nitrilotriacetic acid, ammonium nitrilotriacetate, hydroxyethylethylenediaminetriacetic acid, hydroxyethylethylenediamine triacetate, triethylenetetramine hexaacetic acid, triethylenetetramine. (6) Sodium acetate and the like can be mentioned. The content of the chelating agent in the rinsing agent composition of the present invention is preferably 0.01 to 1% by weight.

<Anionic surfactant>
Examples of the anionic surfactant include fatty acid soap, carboxylate such as alkyl ether carboxylate, alkylbenzene sulfonate, sulfonate such as alkylnaphthalene sulfonate, higher alcohol sulfate ester salt, and alkyl ether sulfate. Examples thereof include sulfate ester salts such as, and phosphoric acid ester salts such as alkyl phosphates.

<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 polyoxy. Examples thereof include polyethylene glycol type such as alkylene (cured) castor oil, polyhydric alcohol type such as sucrose fatty acid ester, and fatty acid alkanolamide.

<Oxidizing agent>
Examples of the oxidizing agent include peroxides such as permanganic acid and peroxo acid, chromic acid, nitric acid, and salts thereof.

In one or more embodiments, the rinsing composition of the present disclosure preferably contains substantially no abrasive grains from the viewpoint of reducing LPD. For example, the content of the abrasive grains in the rinse agent composition portion of the present disclosure is preferably 0.1% by mass or less, more preferably 0.01% by mass or less, and even more preferably substantially 0% by mass.

[PH of rinse agent composition]
The pH of the rinsing agent composition of the present disclosure at 25 ° C. is preferably 2 or more, more preferably 2.5 or more, from the viewpoint of reducing LPD, shortening the washing time, and improving the storage stability of the rinsing agent composition. Preferably, 3 or more is more preferable, 3.5 or more is even more preferable, 4 or more is even more preferable, and from the same viewpoint, 12 or less is preferable, 10 or less is more preferable, 9 or less is further preferable, and 8 or less is preferable. Is even more preferable, 7 or less is even more preferable, and 6.5 or less is even more preferable. The pH can be adjusted by appropriately adding a pH adjusting agent, if necessary. Here, the pH at 25 ° C. can be measured using a pH meter, and specifically, can be measured by the method described in Examples.

[Manufacturing method of rinse agent composition]
The rinse agent composition of the present disclosure can be produced, for example, by a production method including a step of blending component A, component B, and if necessary, an arbitrary component by a known method. In the present disclosure, "blending" includes mixing component A, component B, and optionally, any component at the same time or in any order. The formulation can be performed using, for example, a mixer such as a homomixer, a homogenizer, an ultrasonic disperser, and a wet ball mill. The preferable blending amount of each component in the method for producing the rinsing agent composition of the present disclosure can be the same as the preferable content of each component in the rinsing agent composition of the present disclosure described above.

In the present disclosure, "content of each component in the rinsing agent composition" refers to the content of each component at the time of using the rinsing agent composition, that is, at the time when the rinsing agent composition is used for the rinsing treatment.

[Concentrate of rinse agent composition]
The rinse agent composition of the present disclosure may be stored and supplied in a concentrated state as long as its storage stability is not impaired. In this case, it is preferable in that the manufacturing and transportation costs can be further reduced. The concentrate of the rinse agent composition of the present disclosure may be appropriately diluted with water so that the content of each component becomes the content of each component described above at the time of use. The concentration ratio is not particularly limited as long as the concentration at the time of polishing after dilution can be secured, but is preferably 2 times or more, more preferably 10 times or more, and further, from the viewpoint of further reducing the manufacturing and transportation costs. It is preferably 20 times or more.

When the rinsing agent composition of the present disclosure is a concentrate, the content of component A in the concentrate of the rinsing agent composition of the present disclosure is preferably 5% by mass or more from the viewpoint of reducing production and transportation costs. It is more preferably 10% by mass or more, further preferably 20% by mass or more, and from the viewpoint of improving storage stability, it is preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass. It is as follows.

When the rinsing agent composition of the present disclosure is a concentrate, the pH of the concentrate of the rinsing agent composition of the present disclosure at 25 ° C. is preferably 1.5 or more, more preferably 1.7 or more, still more preferably 2. And more, preferably 12 or less, more preferably 11 or less, still more preferably 10 or less.

[Manufacturing method of semiconductor substrate]
The rinsing agent composition of the present disclosure is used in one or more embodiments to remove residues remaining on the surface of a silicon wafer after polishing with a polishing liquid composition containing abrasive grains.
The rinsing agent composition of the present disclosure is used in one or more embodiments in the rinsing step after the polishing step of the silicon wafer in the manufacturing process of the semiconductor substrate.
That is, the present disclosure relates to a semiconductor substrate manufacturing method (hereinafter, also referred to as “the semiconductor substrate manufacturing method of the present disclosure”) including the following steps (1), (2) and (3) in one aspect.
(1) A step of polishing a silicon wafer to be polished using a polishing liquid composition containing abrasive grains (hereinafter, also referred to as “polishing step”).
(2) A step of rinsing a silicon wafer polished in step (1) (hereinafter, also referred to as “polished silicon wafer”) using the rinsing agent composition of the present disclosure (hereinafter, also referred to as “rinsing step”). ).
(3) A step of cleaning a silicon wafer (hereinafter, also referred to as “after-rinse silicon wafer”) that has been rinsed in step (2) (hereinafter, also referred to as a “cleaning step”).

<Silicon wafer to be polished>
Examples of the silicon wafer to be polished include a single crystal 100-sided silicon wafer, a 111-sided silicon wafer, a 110-sided silicon wafer, and the like. The resistance of the silicon wafer is preferably 0.0001 Ω · cm or more, more preferably 0.001 Ω · cm or more, still more preferably 0.01 Ω · cm or more, and even more, from the viewpoint of reducing residues on the wafer surface. It is preferably 0.1 Ω · cm or more, and preferably 100 Ω · cm or less, more preferably 50 Ω · cm or less, still more preferably 20 Ω · cm or less. From the same viewpoint, the resistance of the silicon wafer is preferably 0.0001 Ω · cm or more and 100 Ω · cm or less, more preferably 0.001 Ω · cm or more and 100 Ω · cm or less, still more preferably 0.01 Ω · cm or more and 100 Ω ·. It is cm or less, more preferably 0.1 Ω · cm or more and 100 Ω · cm or less, still more preferably 0.1 Ω · cm or more and 50 Ω · cm or less, still more preferably 0.1 Ω · cm or more and 20 Ω · cm or less.

<Process (1): Polishing process>
The polishing steps include a wrapping (rough polishing) step of flattening a silicon wafer obtained by slicing a silicon single crystal ingot into a thin disk shape, and a silicon wafer surface after etching the wrapped silicon wafer. There is a finish polishing process to mirror the surface. The rinse agent composition of the present disclosure is more preferably used after the finish polishing step.

In the polishing step, for example, the silicon substrate to be polished can be pressed against a surface plate to which a polishing pad is attached, and the silicon substrate to be polished can be polished with a polishing pressure of 3 to 20 kPa. The polishing pressure is the pressure of the surface plate applied to the surface to be polished of the silicon substrate to be polished during polishing. In the polishing step, for example, the silicon substrate to be polished is pressed against a surface plate to which a polishing pad is attached, and the temperature is preferably 15 ° C. or higher, more preferably 20 or higher, and preferably 40 ° C. or lower, more preferably 30 ° C. or lower. The silicon substrate to be polished can be polished at the temperature of the polishing liquid composition and the surface temperature of the polishing pad.

The abrasive composition used in the polishing step is not particularly limited, but contains silica particles. Examples of the silica particles include colloidal silica, fumed silica, pulverized silica, and surface-modified silica thereof. Colloidal silica is preferable from the viewpoint of improving the polishing speed, reducing the surface roughness (haze), and reducing the surface defects (LPD) on the wafer surface. The silica particles may be one kind or a combination of two or more kinds. The content of the silica particles in the abrasive composition is, for example, 0.05% by mass or more and 10% by mass or less.
The polishing agent composition is preferably a nonionic water-soluble polymer, more preferably an alkylene oxide group in the molecule, from the viewpoint of achieving improvement in polishing speed, reduction in surface roughness (haze) and reduction in surface defects (LPD). Alternatively, it contains a nonionic water-soluble polymer having a hydroxyl group and having a weight average molecular weight of 1,000 or more and less than 500,000. In the present disclosure, "water-soluble" means having a solubility of 0.5 g / 100 mL or more, preferably 2 g / 100 mL or more, in water (20 ° C.). When the nonionic polymer has an alkylene oxide group in the molecule, examples of the alkylene oxide group include an ethylene oxide group and a propylene oxide group. The nonionic polymer is selected from polyglycerin, hydroxyalkyl cellulose, polyvinyl alcohol, and polyhydroxyethyl acrylamide from the viewpoint of achieving improvement in polishing speed, reduction in surface roughness (haze), and reduction in surface defects (LPD). At least one is mentioned.
The pH of the polishing liquid composition is preferably more than 8.5, more preferably 9 or more, further preferably 9.5 or more, still more preferably 10 or more, from the viewpoint of achieving both improvement in polishing speed and storage stability. From the viewpoint of improving the surface quality, 14 or less is preferable, 13 or less is more preferable, 12.5 or less is further preferable, 12 or less is further preferable, 11.5 or less is further preferable, and 11 or less is further preferable.
The polishing liquid composition contains water as a medium, and the content of water in the polishing liquid composition can be the residue of the abrasive grains, the nonionic polymer, and any component described later. In one or more embodiments, the polishing liquid composition may contain optional components such as a water-soluble polymer, a basic compound, a pH adjuster, a preservative, alcohols, and a chelating agent.

<Process (2): Rinse process>
In the rinsing step, for example, the rinse agent composition of the present disclosure is supplied between the silicon wafer polished in the step (1) (hereinafter, also referred to as “polished silicon wafer”) and the pad, and the polished silicon wafer. With the pad in contact with the pad, the pad is polished and then moved relative to the silicon wafer. The rinsing treatment in the rinsing step can be performed by using the polishing apparatus used in the polishing step. The rotation speed of the pad, the rotation speed of the silicon wafer after polishing, the load set in the polishing apparatus provided with the pad, the supply speed of the rinse agent composition of the present disclosure, etc. may be the same as or different from the corresponding conditions in the polishing process. May be. 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 rinsing time means the time during which the rinsing agent composition is being supplied.

The rinsing step may include a water rinsing treatment using water as a rinsing liquid before the rinsing treatment performed using the rinsing agent composition of the present disclosure. The water rinsing 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 any type such as a non-woven fabric type and a suede type. Further, the pad used in the polishing step may be used as it is in the rinsing step without replacement, and in this case, the pad may contain some abrasive grains of the polishing liquid composition. The rinsing step can also be performed on the silicon wafer as it is attached to the polishing device immediately after the polishing step.

Examples of the temperature of the rinsing agent composition used in the rinsing step include 5 to 60 ° C.

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

<Process (3): Cleaning process>
In the cleaning step, for example, the silicon wafer rinsed in the step (2) (hereinafter, also referred to as “post-rinse silicon wafer”) should be immersed in a cleaning agent or the rinsed silicon wafer should be cleaned. Inject a cleaning agent onto the surface. As the cleaning agent, a conventionally known cleaning agent may be used, and examples thereof include an inorganic cleaning agent containing at least one selected from ozone, hydrogen peroxide, ammonia, hydrochloric acid, sulfuric acid, hydrofluoric acid and ozone water. The cleaning time may be set according to the cleaning method.

The semiconductor substrate manufacturing method of the present disclosure may further include a step of forming an element separation film, a step of flattening an interlayer insulating film, a step of forming a metal wiring, and the like.

[Rinse method for silicon wafer]
The present disclosure comprises, in one embodiment, a step of rinsing a polished silicon wafer with the rinsing agent composition of the present disclosure (rinsing step), a method for rinsing a silicon wafer (hereinafter, "rinsing of the present disclosure"). Also called "method"). The rinsing step in the rinsing method of the present disclosure can be performed in the same manner as the rinsing step (2) in the semiconductor substrate manufacturing method of the present disclosure described above. According to the rinsing method of the present disclosure, since the rinsing agent composition of the present disclosure is used, the residual amount of abrasive grains on the silicon wafer after polishing can be remarkably reduced, and in addition, aggregation of the abrasive grains can be suppressed. Therefore, it is possible to shorten the time for cleaning the silicon wafer performed after the rinsing process and reduce the LPD.

Hereinafter, the present disclosure will be described in more detail by way of examples, but these are exemplary and the present disclosure is not limited to these examples.

1. 1. Measurement method of various parameters [Average degree of condensation of alkyl polyglucoside]
The average degree of condensation of the alkylpolyglucoside (AG) was calculated by the method described later after removing the polysaccharide by solid-phase extraction under the following conditions.
(Solid phase extraction)
After conditioning with methanol and ion-exchanged water, a sample (2 mL) was charged, the sugar component was eluted with an aqueous acetonitrile solution (5 wt%: 10 mL), and then the AG component was eluted with methanol (10 mL).
Column: InertSep C18 2000mg (GL Science)
Sample: 2 wt% (dissolved in a 5 wt% aqueous solution of acetonitrile)

(Calculation method of average degree of condensation)
The average degree of condensation of the alkyl polyglucoside used in the preparation of the rinsing agent composition was measured by applying the following conditions by nuclear magnetic resonance spectroscopy (NMR) after solid phase extraction, and was calculated based on the peak in the obtained chart. ..
Equipment: Mercury 400BB (400 MHz, manufactured by Varian)
Observation width: 6410.3Hz
Data point: 64 K
Pulse width: 45 μS
Pulse delay time: 10 seconds Total number of times: 64 times Measurement temperature: Room temperature Spin: × 16
Solvent: pyridine-d ₅ (D2O drops dropped)
Condensation degree calculation method:
Degree of condensation = {[(the number of protons adjacent to the oxygen atom appearing at 3.5 to 5.3 ppm) / (the number of protons of the alkyl moiety appearing at 0 to 2.0 ppm)]-2} / 7

[PH of rinse agent composition]
The pH value of the rinsing agent composition and its concentrate at 25 ° C. is a value measured using a pH meter (“HM-30G” manufactured by Toa DK Co., Ltd.), and the electrode of the pH meter is used as the rinsing agent composition or. It is a value after 1 minute of immersion in the concentrate.

2. 2. Preparation of Rinse Agent Composition (Examples 1 to 6 and Comparative Examples 1 to 3)
The alkyl polyglucoside (component A or non-component A) shown in Table 1 and ion-exchanged water are stirred and mixed, and if necessary, using an aqueous hydrochloric acid solution or 28% by mass ammonia water (Kishida Chemical Co., Ltd. reagent special grade) 25 The pH at ° C. was adjusted to 4, and a concentrated solution (concentration ratio: 20 times) of the rinse agent composition of Examples 1 to 6 and Comparative Examples 1 to 3 was obtained.
The content of the component A or the non-component A shown in Table 1 is a value for the rinse agent composition obtained by diluting the concentrated solution 20 times. The content of ion-exchanged water is the residue excluding alkyl polyglucoside (component A or non-component A), hydrochloric acid or ammonia.

Details of the alkyl polyglucoside (component A or non-component A) used in the preparation of each rinse agent composition are shown in Table 1 and the following.
(Component A)
A1: Alkyl polyglucoside [Linear alkyl group with 10 carbon atoms, average sugar condensation degree 2.1]
A2: Alkyl polyglucoside [Linear alkyl group with 10 carbon atoms, average sugar condensation degree 2.7]
A3: Alkyl polyglucoside [Linear alkyl group with 12 carbon atoms, average sugar condensation degree 2.1]
A4: Alkyl polyglucoside [Linear alkyl group with 12 carbon atoms, average sugar condensation degree 2.3]
A5: Alkyl polyglucoside [Linear alkyl group with 10 carbon atoms, average sugar condensation degree 3.4]
A6: Alkyl polyglucoside [Linear alkyl group with 12 carbon atoms, average sugar condensation degree 2.9]
(Non-ingredient A)
A7: Alkyl polyglucoside [branched alkyl group with 10 carbon atoms, average sugar condensation degree 1.3]
A8: Alkyl polyglucoside [Linear alkyl group with 9 carbon atoms, average sugar condensation degree 1.5]
A9: Alkyl polyglucoside [Linear alkyl group with 9 carbon atoms, average sugar condensation degree 1.6]

(Method for synthesizing alkyl glycosides)
In the above-mentioned alkyl polyglycoside, a sugar is reacted with an excess alcohol in the presence of an acidic catalyst, an inorganic acid salt is added to a reaction solution containing the alkyl polyglycoside and an unreacted alcohol, and then the unreacted alcohol is distilled. Manufactured by the method of distilling off.

3. 3. Rinse method The rinse agent composition (pH 5) obtained by diluting the rinse agent composition (concentrate) 20-fold with ion-exchanged water is filtered immediately before the start of the rinse treatment (compact cartridge filter "MCP-" manufactured by Advantech Co., Ltd. LX-C10S "))), and under the following rinsing conditions, the following silicon wafer (silicon single-sided mirror wafer with a diameter of 200 mm (conduction type: P, crystal orientation: 100, resistance 0.1Ω ・ cm or more 100Ω ・) Rinse treatment was performed on the silicon wafer (less than cm). Prior to the rinsing treatment, rough polishing was performed on the silicon wafer in advance using a commercially available polishing liquid composition. Then, finish polishing was performed under the following conditions. Immediately after that, each rinsing agent composition was used for rinsing under the following conditions. The Haze of the silicon wafer after rough polishing and subject to finish polishing was 2.680 (ppm). Is a value on a dark field wide oblique incident channel (DWO) measured using "Surfscan SP1-DLS" manufactured by KLA Tencor.

[Polishing liquid composition used for finish polishing]
The polishing liquid composition used for finish polishing was silica particles (“PL-3” manufactured by Fuso Chemical Industry Co., Ltd.), HEC (hydroxyethyl cellulose, “SE-400” manufactured by Daicel Co., Ltd., weight average. Molecular weight 250,000), PEG (polyethylene glycol, "PEG6000" manufactured by Wako Pure Chemical Industries, Ltd., Wako first grade, weight average molecular weight 6,000), ammonia water (Kishida Chemical Co., Ltd., reagent special grade), Ion-exchanged water was stirred and mixed to prepare a concentrated solution. Then, the concentrated solution was diluted 40-fold with ion-exchanged water immediately before use to obtain a polishing solution composition for finish polishing. The content of each component in the polishing liquid composition for finish polishing is 0.17% by mass for silica particles, 0.01% by mass for HEC, 0.01% by mass for ammonia, and 0.0008% by mass for PEG. there were. The pH of the polishing liquid composition for finish polishing was 10.

[Finishing conditions]
Polishing machine: Okamoto Kou Seisakusho single-sided 8-inch polishing machine "GRIND-X SPP600s"
Polishing pad: Suede pad manufactured by Toray Cortex (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 speed of polishing liquid composition: 150 g / minute Temperature of polishing liquid composition: 23 ° C.
Carrier rotation speed: 60 rpm

[Rinse condition]
Polishing machine: Okamoto Kou Seisakusho single-sided 8-inch polishing machine "GRIND-X SPP600s"
Polishing pad: Suede pad manufactured by Toray Cortex (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: 20 seconds Supply rate of rinse agent composition: 1000 mL / min Temperature of rinse agent composition: 23 ° C.
Carrier rotation speed: 30 rpm

4. Cleaning method After rinsing, ozone cleaning and dilute hydrofluoric acid cleaning were performed on the silicon wafer as follows. In ozone cleaning, an aqueous solution containing 20 ppm ozone 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 3 minutes. At this time, the temperature of ozone water was set to room temperature. Next, washing with dilute hydrofluoric acid was performed. In dilute hydrofluoric acid cleaning, an aqueous solution containing 0.5% by mass of ammonium hydrogen fluoride (special grade: Nakaraitex Co., Ltd.) is sprayed from a nozzle toward the center of a silicon wafer rotating at a flow rate of 1 L / min at 600 rpm 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. In spin drying, the silicon wafer was rotated at 1500 rpm.

5. Evaluation [Evaluation of LPD of silicon wafer]
To evaluate the LPD on the surface of the silicon wafer after cleaning, the number of particles having a particle size of 45 nm or more on the surface of the silicon wafer is measured using a surface roughness measuring device "Surfscan SP1-DLS" (manufactured by KLA Corporation). Evaluated by that. The evaluation result of LPD shows that the smaller the numerical value is, the less the surface defect is. The LPD was measured for each of four silicon wafers, and the average values for each were shown in the table below.
In Comparative Examples 1 to 3, the number of particles was large and measurement was impossible.

[Evaluation of wettability of silicon wafer surface (wetting area of silicon wafer)]
As a pretreatment, a silicon wafer cut into a 40 × 40 mm square was immersed in a 1% dilute hydrofluoric acid aqueous solution for 3 minutes to remove an oxide film, washed with ultrapure water for 10 seconds, and air blow dried. Then, after polishing for 5 minutes using the same polishing liquid composition as the polishing liquid composition used for the above-mentioned finish polishing, water rinsing with ultrapure water was carried out for 10 seconds, and then each rinsing agent composition described above was used. Rinse for 20 seconds. Then, the silicon wafer was immersed in a tub filled with ultrapure water, and after 10 seconds of pulling up, the area of the hydrophilized portion when the silicon wafer was fixed horizontally was calculated by image analysis. The case where the entire surface of the silicon wafer was wet was defined as 100%.
<Evaluation criteria>
A: 100%
B: More than 80% and less than 100% C: 80% or less

As shown in Table 1 above, it was found that the rinse agent compositions of Examples 1 to 6 were able to reduce the LPD of the polished silicon wafer surface as compared with the rinse agent compositions of Comparative Examples 1 to 3. ..

Since the rinsing agent composition of the present disclosure can reduce the LPD of the polished silicon wafer surface, it is possible to manufacture a silicon wafer with reduced surface defects, which is useful in mass production of semiconductor substrates.

Claims (6)

A rinsing agent composition used for rinsing the surface of a polished silicon wafer containing the following component A and the following component B.
Component A: Alkyl polyglucoside with an average degree of condensation of 1.9 or more Component B: Water The rinse agent composition according to claim 1, wherein the component A is a compound represented by the following general formula (I).
R-Gy (I)
However, in the formula (I), R indicates an alkyl group having 8 to 18 carbon atoms, G indicates a residue derived from a sugar, and y indicates the average degree of condensation of the sugar, which is a number of 1.9 or more and 5 or less. Is. The rinse agent composition according to claim 1 or 2, wherein the proportion of the alkyl glycoside having a degree of condensation of 1 contained in the component A is 20% or more. The rinse agent composition according to any one of claims 1 to 3, which does not substantially contain abrasive grains. A method for rinsing a silicon wafer, which comprises a step of rinsing the polished silicon wafer with the rinsing agent composition according to any one of claims 1 to 4. A method for manufacturing a semiconductor substrate, which comprises the following steps (1), (2), and (3).
(1) A step of polishing a silicon wafer to be polished using a polishing liquid composition containing abrasive grains.
(2) A step of rinsing the silicon wafer polished in the step (1) using the rinsing agent composition according to any one of claims 1 to 4.
(3) A step of cleaning the silicon wafer rinsed in the step (2).