Surface treatment composition, surface treatment method using the same and kit for preparing a surface treatment composition

Abstract

A surface treatment composition comprising a first surfactant, a second surfactant, a basic compound, and water, wherein the surface treatment composition has a pH of 8 or more, wherein the second surfactant has a weight-average molecular weight of one-half or less of the weight-average molecular weight of the first surfactant, and wherein the sum of a content of the first surfactant and a content of the second surfactant is 0.00001 to 0.1 mass%, and wherein a ratio of the total number of carbon atoms of the second surfactant to a sum of a total number of carbon atoms of the first surfactant and the total number of carbon atoms of the second surfactant is 1 to 90%.

Description

Technical area

[0001] The present invention relates to a surface treatment composition primarily used in performing a surface treatment, such as polishing, etching, rinsing, or washing, of a substrate. The present invention also relates to a kit for preparing the surface treatment composition and a method for subjecting a substrate to a surface treatment using the surface treatment composition. State of the art

[0002] The miniaturization of semiconductor device design rules is progressing every year due to the high level of integration and increasing speed of integrated circuits, such as ULSI circuits used in computers. Therefore, small defects on a semiconductor substrate have a detrimental effect on the performance of the semiconductor device. Currently, control of defects in the nanoscale, which have traditionally not been problematic, is required.

[0003] A surface inspection device is used to inspect defects on a semiconductor substrate surface. The defects detected by a surface inspection device include foreign matter and residues on the semiconductor substrate. The foreign matter and residues cannot be completely removed by polishing, rinsing, and washing. A typical surface inspection device irradiates the surface of a semiconductor substrate with light, such as a laser beam, and receives and analyzes the reflected light as a signal to determine the presence and size of the defects.

[0004] When a polished, high-gloss semiconductor substrate surface is irradiated with intense light, a coating can be detected by the diffuse reflection caused by the roughness of the semiconductor substrate surface. This coating is referred to as haze. Haze can be used as a measure of the coarseness of a semiconductor substrate surface. If haze exists on a semiconductor substrate surface, the diffuse reflection light generated by the haze can generate noise, which can interfere with defect detection performed by a surface inspection device.

[0005] As the size of the defects to be detected, i.e., the size of the defects to be controlled, decreases, the need to improve the haze level increases. It is known that the haze level of a semiconductor substrate surface is also strongly influenced by etching.

[0006] On the other hand, a surface treatment composition used for polishing or etching a substrate generally comprises a basic compound for etching the substrate surface. A substrate treatment composition used for rinsing or washing a substrate may also contain a basic compound to enhance a rinsing or washing effect. If the pH of the surface treatment composition is adjusted to 8 or more by mixing a basic compound, roughness may be disadvantageously generated on a substrate surface due to the etching effect caused by the basic compound.Therefore, when a substrate is subjected to surface treatment using a composition containing a basic compound and having a pH of 8 or more, the reduction of the turbidity of the surface of the substrate subjected to the surface treatment must be achieved by controlling the etching effect caused by the basic compound.

[0007] Patent Document 1 discloses a polishing composition containing a surfactant made of a copolymer of polyoxyethylene and polyoxypropylene for primarily reducing haze on a semiconductor substrate surface after polishing. However, the haze-reducing effect of the polishing composition described in Patent Document 1 is insufficient to control nanoscale defects.

[0008] Patent Document 2 discloses a CMP slurry comprising an abrasive grain and a mixed surfactant comprising a first polyether-type nonionic surfactant having an HLB value in the range of 3 to 9 at room temperature and a second polyether-type nonionic surfactant having an HLB value in the range of 10 to 20 at room temperature.

[0009] Patent Document 3 discloses a polishing composition containing hydroxyethylcellulose, polyethylene oxide, an alkaline compound, water, and silicon dioxide. The composition is used in a polishing process for reducing the degree of haze on a wafer surface. State-of-the-art documents Patent Document 1: Japanese Patent Laid-Open Publication JP 2005-85858 A Patent document 2: US 2006 / 0 030 503 A1 Patent document 3: DE 603 ​​18 172 T2 Summary of the inventionProblems to be solved by the invention

[0010] Accordingly, a main object of the present invention is to suppress roughness on a substrate surface caused by non-uniform or excessive etching generated by the action of a basic compound contained in a surface treatment composition, that is, to provide a surface treatment composition capable of further reducing haze on a substrate surface. Means to solve the problem

[0011] The present inventors have conducted serious investigations and discovered that by blending at least two surfactants with different molecular weights in a surface treatment composition containing a basic compound and having a pH of 8 or more, and particularly by blending a first surfactant in combination with a second surfactant having a weight-average molecular weight of one-half or less of the weight-average molecular weight of the first surfactant, the etching effect of a substrate surface caused by the basic compound can be controlled. The present invention is based on this finding.

[0012] That is, in order to solve the above-mentioned problem and according to a first aspect of the present invention, there is provided a surface treatment composition containing a first surfactant, a second surfactant, a basic compound and water, wherein the surface treatment composition has a pH of 8 or more, the second surfactant has a weight-average molecular weight of one half or less of the molecular weight of the first surfactant, and the sum of the content of the first surfactant and the content of the second surfactant is 0.00001 to 0.1 mass%,and wherein a ratio of the total number of carbon atoms of the second surfactant to a sum of a total number of carbon atoms of the first surfactant and the total number of carbon atoms of the second surfactant is 1 to 90%.,

[0013] According to a second aspect of the present invention, a kit for preparing the surface treatment composition according to the first aspect is provided.

[0014] According to a third aspect of the present invention, there is provided a method for subjecting a substrate to a surface treatment using the surface treatment composition according to the first aspect. Effect of the invention

[0015] The present invention can appropriately control the etching effect on a substrate surface caused by a basic compound. Accordingly, the present invention provides a surface treatment composition that can suppress roughness on a substrate surface to reduce haze, and a surface treatment method. The present invention also provides a kit suitable for easily preparing such a surface treatment composition. Ways of carrying out the invention

[0016] Embodiments according to the present invention will be described below. 1. Surface treatment composition of the present invention

[0017] A surface treatment composition of the present invention according to claim 1 contains a first surfactant, a second surfactant, a basic compound and water, and has a pH of 8 or more. Surfactants

[0018] The first surfactant and the second surfactant contained in the surface treatment composition of the present invention have different molecular weights from each other. According to the invention, the second surfactant has a weight-average molecular weight of one-half or less of the weight-average molecular weight of the first surfactant. If the weight-average molecular weight of the second surfactant exceeds one-half of the weight-average molecular weight of the first surfactant, a sufficient effect for suppressing the roughness of a substrate surface cannot be achieved.

[0019] In the surface treatment composition, the sum of the content of the first surfactant and the content of the second surfactant must be 0.00001 mass% or more, and preferably 0.0001 mass% or more. If the sum of the contents of the first surfactant and the second surfactant is less than 0.00001 mass%, a sufficient effect for suppressing the roughness of a substrate surface cannot be achieved.

[0020] The sum of the content of the first surfactant and the content of the second surfactant in the surface treatment composition must be 0.1 mass% or less, and preferably 0.05 mass% or less. If the sum of the contents of the first surfactant and the second surfactant exceeds 0.1 mass%, a sufficient effect for suppressing the roughness of a substrate surface cannot be achieved, and the substrate treatment composition is disadvantageously prone to foaming.

[0021] Although a detailed mechanism of how the roughness of a substrate surface is suppressed using a combination of the first surfactant and the second surfactant is not clear, the mechanism is believed to be as follows. That is, both the first surfactant and the second surfactant are adsorbed onto a substrate surface to serve to protect the substrate surface from non-uniform or excessive etching, which can be generated by the action of a basic compound. Since the first surfactant has a comparatively high molecular weight, the first surfactant has a greater effect on protecting the substrate surface than the second surfactant. However, the first surfactant cannot be densely adsorbed to the substrate surface.On the other hand, the second surfactant, which has a comparatively low molecular weight, can be adsorbed onto the substrate surface, filling gaps where the first surfactant cannot be adsorbed. Therefore, it is believed that the substrate surface can be well protected by using the first surfactant and the second surfactant in combination to suppress substrate surface roughness.

[0022] In the present invention, the ratio of the total number of carbon atoms of the second surfactant to the sum of the total number of carbon atoms of the first surfactant and the total number of carbon atoms of the second surfactant is 1% or more, more preferably 5% or more, even more preferably 15% or more, and particularly preferably 30% or more. When the ratio is 1% or more, and particularly 5% or more, 15% or more, or 30% or more, the roughness of a substrate surface can be further suppressed. Although the reason is not clear, it is believed that carbon atoms contained in the second surfactant serve as adsorption points when the second surfactant is adsorbed onto a substrate surface.Therefore, it is believed that the effect of the second surfactant adsorbed on a substrate surface to fill the gaps on which the first surfactant was not adsorbed is shown by an increase in the total number of carbon atoms of the second surfactant.

[0023] In the present invention, the ratio of the total number of carbon atoms of the second surfactant to the sum of the total number of carbon atoms of the first surfactant and the total number of carbon atoms of the second surfactant is 90% or less, more preferably 85% or less, even more preferably 75% or less, and particularly preferably 65% ​​or less. When the ratio is 90% or less, and particularly preferably 85% or less, 75% or less, or 65% or less, the roughness of a substrate surface can be further suppressed. Although the reason is not clear, it is believed that the contribution of the first surfactant, which has a great effect on protecting the substrate surface, is increased.

[0024] The total number of carbon atoms of the first surfactant and the total number of carbon atoms of the second surfactant can be obtained as follows. The number of moles of each surfactant is calculated from the surfactant content in the surface treatment composition and the surfactant's weight-average molecular weight. The surfactant's molecular chain number is calculated by multiplying the number of moles by Avogadro's constant. Then, the average carbon number of each surfactant molecular chain is calculated from the weight-average molecular weight and the surfactant's structural formula. The average carbon number is multiplied by the previously calculated number of surfactant molecular chains.That is, the total number of carbon atoms of each surfactant can be calculated by the following formula.

[0025] Total number of carbon atoms of each surfactant = (average number of carbon atoms in each molecular chain of the surfactant) x (mass of surfactant / weight average molecular weight of the surfactant) x Avagadro's constant.

[0026] Although the weight-average molecular weight of the first surfactant is not particularly limited, the weight-average molecular weight is preferably 500 to 20,000, and more preferably 1,000 to 10,000, in order to further improve the effect of suppressing the roughness of a substrate surface.

[0027] The weight-average molecular weight of the second surfactant is not particularly limited, as long as the weight-average molecular weight of the second surfactant is one-half or less of the weight-average molecular weight of the first surfactant. The weight-average molecular weight of the second surfactant is preferably 200 to 10,000, more preferably 200 to 5,000, and even more preferably 300 to 1,000, to further improve the effect of suppressing the roughness of a substrate surface.

[0028] Although each of the first surfactant and the second surfactant can independently be an ionic surfactant or a nonionic surfactant, both surfactants are preferably nonionic surfactants. Since foaming of the surface treatment composition is suppressed when nonionic surfactants are used compared to the case where a cationic surfactant or an anionic surfactant is used, handling during production and use of the surface treatment composition is simplified. Since nonionic surfactants do not change the pH of the surface treatment composition, control of the pH of the surface treatment composition during production and use is simplified.Furthermore, nonionic surfactants have excellent biodegradability and weak toxicity to a living body, and therefore have little impact on the environment and little anxiety in handling.

[0029] The types of the first surfactant and the second surfactant used in the surface treatment composition of the present invention are not particularly limited. Specific examples thereof include polyoxyalkylene adducts such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, polyoxyethylene fatty acid esters, and polyoxyethylene sorbitan fatty acid esters; simple oxyalkylene polymer substances such as polyethylene glycol and polypropylene glycol; and a copolymer of a variety of oxyalkylenes such as diblock, triblock, random, and alternative types of polyoxyethylene-polyoxypropylene.

[0030] Polyoxyethylene-polyoxyalkylene copolymers, polyoxyethylene alkylene ethers, and polyoxyethylene sorbitan fatty acid esters can be suitably used as the first surfactant. Among these, triblock-type polyoxyethylene-polyoxyalkylene copolymers are particularly preferred. The first surfactant may contain one of these compounds or two or more of them in combination.

[0031] Polyoxyethylene alkyl ether, polyoxyethylene sorbitan fatty acid ester, and polyethylene glycol can be suitably used as the second surfactant. Among these, polyoxyethylene alkyl ether, and especially straight-chain polyoxyethylene alkyl ether, is the most preferred. The second surfactant may contain one of these compounds or two or more of them in combination.

[0032] Although the HLB (hydrophilic-lipophilic balance) value of the first surfactant and the HLB value of the second surfactant are not particularly limited, the HLB values ​​are preferably 12 or more from the standpoint of obtaining good water solubility. When the HLB values ​​of the first surfactant and the second surfactant are 12 or more, the first surfactant and the second surfactant hardly adhere to a substrate surface. Furthermore, the stability of the surface treatment composition is improved. The HLB value is determined here by the Griffin method. According to the Griffin method, the HLB value is calculated as 20 times the sum of the molecular weights of the hydrophilic parts / the sum of the molecular weights of the hydrophilic parts and the hydrophobic parts.Examples of hydrophilic moieties include an oxyethylene group, a hydroxyl group, a carboxyl group, and an ester. Examples of hydrophobic moieties include an oxypropylene group, an oxybutylene group, and an alkyl group. Basic compound

[0033] The surface treatment composition of the present invention contains the basic compound. The pH of the surface treatment composition is adjusted to 8 or more by adding the basic compound. As described above, the etching effect caused by the basic compound is increased when the pH of the surface treatment composition is 8 or more, and especially 9 or more.

[0034] As a result, the roughness of a substrate surface can be generated. However, the roughness of a substrate surface is suppressed by the above-mentioned effects of the first surfactant and the second surfactant.

[0035] The basic compound used in the surface treatment composition of the present invention is not particularly limited. Specific examples thereof include ammonia, potassium hydrate, sodium hydrate, tetramethylammonium hydrate, tetraethylammonium hydrate, ammonium acid carbonate, ammonium carbonate, potassium bicarbonate, potassium carbonate, sodium hydrogen carbonate, sodium carbonate, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylenediamine, diethylenetriamine, triethylenetetraamine, anhydrous piperazine, piperazine hexahydrate, 1-(2-aminoethyl)piperazine, and N-methylpiperazine. The basic compound may contain one of these compounds or two or more of the compounds in combination.

[0036] When a substrate to be subjected to the surface treatment using the surface treatment composition is a silicon wafer, the basic compound is preferably ammonia, an ammonium salt, an alkali metal hydroxide, an alkali metal salt or a quaternary ammonium hydroxide, more preferably ammonia, potassium hydrate, sodium hydrate, tetramethylammonium hydrate, tetraethylammonium hydrate, ammonium hydrogencarbonate, ammonium carbonate, potassium hydrogencarbonate, potassium carbonate, sodium hydrogencarbonate or sodium carbonate, and more preferably ammonia, potassium hydrate, sodium hydrate, tetramethylammonium hydrate or tetraethylammonium hydrate, and particularly preferably ammonia, in order to suppress the metallic contamination of the substrate to be subjected to the surface treatment.

[0037] The content of the basic compound in the surface treatment composition is not particularly limited as long as the pH of the surface treatment composition is 8 or more. The content is generally from 0.0001 mass% to 0.5 mass%. When a substrate to be surface treated using the surface treatment composition is a silicon wafer, the content of the basic compound in the surface treatment composition is preferably from 0.0001 mass% to 0.5 mass%, and more preferably from 0.001 mass% to 0.25 mass%. When the content of the basic compound is within any of the above-mentioned ranges, the basic compound has a practical advantage in that the etching effect caused by the basic compound is moderately reduced through the functions of the first surfactant and the second surfactant. <wasser>

[0038] The water contained in the surface treatment composition serves to dissolve or disperse the other components contained in the surface treatment composition. It is preferable that the water contains as little as possible impurities that inhibit the action of the other components. Specifically, ion-exchange water from which foreign matter has been removed by passing it through a filter after the impurity ions have been removed with an ion-exchange resin, pure water, ultrapure water, or distilled water is preferred. <partikelbestandteil>

[0039] The surface treatment composition may contain a particulate component. The particulate component serves to physically polish a substrate surface.

[0040] Specific examples of the particulate component to be used include silicon carbide, silicon dioxide, alumina, cerium dioxide, zirconia, and diamond. However, the particulate component is not limited to these. Silicon dioxide, such as colloidal silicon dioxide, fumed silica, or sol-gel precursor silicon dioxide, is preferred because the surface roughness of a substrate is further reduced when silicon dioxide is used.

[0041] When the surface treatment composition is used for polishing a semiconductor substrate, particularly for polishing a silicon wafer, the particulate component contained in the surface treatment composition is preferably colloidal silicon dioxide or highly dispersed silicon dioxide, and more preferably colloidal silicon dioxide. When colloidal silicon dioxide or highly dispersed silicon dioxide is used, especially when colloidal silicon dioxide is used, scratches generated on a substrate surface by polishing are reduced. The particulate component may contain one of the materials described above or two or more of them in combination.

[0042] When the surface treatment composition is used for polishing a semiconductor substrate, particularly for polishing a silicon wafer, the particle component contained in the surface treatment composition preferably has an average primary particle diameter of 5 to 100 nm, and more preferably 10 to 40 nm. The average primary particle diameter is obtained from a specific surface area determined by a specific surface area determination method (BET method) of the powder using gas adsorption.

[0043] When the surface treatment composition is used for polishing a semiconductor substrate, particularly for polishing a silicon wafer, the content of the particulate component contained in the surface treatment composition is preferably 0.01 mass% or more, and more preferably 0.05 mass% or more. When the content of the particulate component is 0.01 mass% or more, and more specifically 0.05 mass% or more, the polishing degree of a substrate is improved.

[0044] The content of the particulate component contained in the surface treatment composition is also preferably 5% by mass or less, and more preferably 1% by mass or less. When the content of the particulate component is 5% by mass or less, and more specifically 1% by mass or less, the dispersion stability of the surface treatment composition is improved. <benetzungsmittel>

[0045] The surface treatment composition may further contain a wetting agent. The wetting agent is effective in keeping a substrate surface hydrophilic. When the wettability of a substrate surface is reduced, foreign matter adhering to the substrate tends to remain without being removed by washing. If the foreign matter remains on a substrate, the surface roughness of the substrate can be reduced.

[0046] Examples of the wetting agent that can be used include a cellulose derivative such as hydroxyethyl cellulose, hydroxypropyl cellulose, and carboxymethyl cellulose; a vinyl polymer such as polyvinyl alcohol, polyvinylpyrrolidone, and poly-N-vinylformamide; a polysaccharide such as starch, cyclodextrin, trehalose, and pullulan; polyacrylamide; and polymethyl methacrylate. Since a cellulose derivative has a high power to impart wettability to a substrate surface, can be easily washed out, and does not remain on the substrate, a cellulose derivative is preferred. Among these, hydroxyethyl cellulose is particularly preferred.

[0047] The weight-average molecular weight of the wetting agent used is generally from 30,000 to 2,000,000. However, when the surface treatment composition is used for polishing a semiconductor substrate, particularly for polishing a silicon wafer, the weight-average molecular weight of the wetting agent is preferably from 50,000 to 1,000,000. When the weight-average molecular weight of the wetting agent is 1,000,000 or less, the dispersion stability of the surface treatment composition is improved. When the weight-average molecular weight of the wetting agent is 50,000 or more, a function of imparting wettability to a substrate surface is sufficiently exhibited.

[0048] The content of the wetting agent in the surface treatment composition is generally 0.001 to 1 mass%. However, when the surface treatment composition is used for polishing a semiconductor substrate, particularly for polishing a silicon wafer, the content of the wetting agent is preferably 0.001 to 0.5 mass%. When the content of the wetting agent is 0.5 mass% or less, the dispersion stability of the surface treatment composition is improved. When the content of the wetting agent is 0.001 mass% or more, a function of imparting wettability to the substrate surface is sufficiently exhibited.

[0049] The surface treatment composition of the present invention is used to subject a substrate to surface treatment such as polishing, rinsing, washing, and etching. Among these, the surface treatment composition is preferably used in a finish polishing process, a rinsing process, or a washing process in which roughness of the substrate surface is particularly problematic.

[0050] Although a substrate to be subjected to surface treatment using the surface treatment composition of the present invention is not particularly limited, a semiconductor substrate or a magnetic substrate, and particularly a silicon substrate, an SiO2 substrate, an SOI (silicon on insulator) substrate, a plastic substrate, a glass substrate, or a quartz substrate, is suitable, in which surface roughness generated by etching caused by the basic compound may be a problem. Among these, the surface treatment composition of the present invention can be preferably used in the surface treatment of a silicon wafer requiring a smooth surface with high precision.

[0051] The surface treatment composition of the present invention can be prepared by dissolving or dispersing the above-mentioned components other than water in water according to a conventional method.

[0052] The surface treatment composition of the present invention has the following advantages.

[0053] The surface treatment composition of the present invention contains the first surfactant and the second surfactant, wherein the second surfactant has a weight-average molecular weight of one half or less of the weight-average molecular weight of the first surfactant; and the sum of the content of the first surfactant and the content of the second surfactant in the surface treatment composition is 0.00001 to 0.1 mass%, and a ratio of the total number of carbon atoms of the second surfactant to a sum of a total number of carbon atoms of the first surfactant and the total number of carbon atoms of the second surfactant is 1 to 90%.The surface treatment composition of the present invention suppresses the roughness of a substrate surface subjected to surface treatment. Therefore, the surface treatment composition of the present invention can be used in applications involving polishing, rinsing, washing, or etching of a substrate surface. Among these, the surface treatment composition can be suitably used in applications for finish polishing the substrate of a silicon wafer and for rinsing the surface of a polished substrate, especially when surface precision is required.

[0054] The surface treatment of the present invention can be carried out as in the following embodiments.

[0055] The surface treatment composition of the present invention may further contain a chelating agent. When the surface treatment composition contains a chelating agent, the metallic contamination of a substrate caused by the surface treatment composition can be suppressed. Examples of suitable chelating agents include an aminocarboxylic acid chelating agent and an organic phosphonic acid chelating agent. Examples of aminocarboxylic acid chelating agents include ethylenediaminetetraacetic acid, sodium ethylenediaminetetraacetate, nitrilotriacetic acid, sodium nitrilotriacetate, ammonium nitrilotriacetate, hydroxyethylethylenediaminetriacetic acid, sodium hydroxyethylethylenediaminetriacetate, diethylenetriaminepentaacetic acid, sodium diethylenetriaminepentaacetate, triethylenetetraaminehexaacetic acid, and sodium triethylenetetraaminehexaacetate.Examples of organic phosphonic acid chelating agents include 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri(methylenephosphonic acid), ethylenediaminetetrakis(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid, ethane-1-hydroxy-1,1,2-triphosphonic acid, ethane-1,2-dicarboxy-1,2-diphosphonic acid, methanehydroxyphosphonic acid, 2-phosphonobutane-1,2-dicarboxylic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid, and α-methylphosphonosuccinic acid.

[0056] The surface treatment composition of the present invention may further contain a known additive such as an antiseptic or a germicidal agent, if needed. 2. Set of the present invention

[0057] A kit of the present invention is used to prepare the surface treatment composition of the present invention. The kit of the present invention contains the first surfactant, the second surfactant having a weight-average molecular weight of one-half or less of the weight-average molecular weight of the first surfactant, and the basic compound, and a ratio of the total number of carbon atoms of the second surfactant to a sum of a total number of carbon atoms of the first surfactant and the total number of carbon atoms of the second surfactant is 1 to 90%, wherein the first surfactant has a weight-average molecular weight of 500 to 20,000.

[0058] One form of the kit is an undiluted solution of the surface treatment composition, which can be prepared by diluting with water. The kit in the form of an undiluted solution is easy to handle as a single product during circulation. The surface treatment composition can be advantageously prepared by a simple water-dilution process.

[0059] The other form of the kit is a multi-component kit, obtained by dividing the components contained in the surface treatment composition into several parts and packaging the components. The multi-component kit can be obtained by dividing the components contained in the surface treatment composition and packaging them separately, or can be packaged in a state where none of the components is mixed with the other components. 3. Surface treatment method of the present invention

[0060] A surface treatment method of the present invention is a method for subjecting a substrate to a surface treatment using the surface treatment composition of the present invention. Specifically, the surface treatment method is a method for polishing, rinsing, washing, or etching the substrate. The surface treatment composition of the present invention can be used in the same apparatus and under the same conditions as those used in conventional surface treatment of a substrate.

[0061] The surface treatment method of the present invention can be carried out as the following embodiment.

[0062] The surface treatment method of the present invention may be a method for polishing a substrate using the surface treatment composition containing the particulate component. In this case, a polishing pad may be used. Although the polishing pad to be used is not particularly limited, the polishing pad may be a nonwoven or suede type. Alternatively, the polishing pad may or may not contain a particulate component.

[0063] When a substrate is polished or rinsed according to the surface treatment method of the present invention, the temperature at which the surface treatment composition is used is not particularly limited. However, the temperature is preferably 5 to 60°C.

[0064] Polishing a substrate performed by the surface treatment method of the present invention may be polishing to improve a damaged layer of the substrate or finish polishing to complete a surface layer of the substrate. Although a polishing time to improve a damaged layer of the substrate depends on the depth of the damaged layer, the polishing time is generally 0.1 to 10 hours. A polishing time in finish polishing to complete a surface layer of the substrate is generally 30 minutes or less.

[0065] When a substrate is washed by the surface treatment method of the present invention, a brush, a diamond dresser, or ultrasonic waves may be used together.

[0066] When a substrate is washed by the surface treatment method of the present invention, the temperature at which the surface treatment composition is used is not particularly limited. However, the temperature is preferably 10 to 90°C. A washing time is generally 1 hour or less. Examples

[0067] Examples and comparative examples of the present invention are described below.

[0068] All or part of the first surfactant, a second surfactant, a basic compound, a particulate component, and a wetting agent were mixed with ion-exchange water to prepare the surface treatment compositions of Examples 1 to 15 and Comparative Examples 1 to 10. The details of the first surfactant and the second surfactant in each of the surface treatment compositions of Examples 1 to 15 and Comparative Examples 1 to 10 are shown in Table 1.Although not shown in Table 1, all of the surface treatment compositions of Examples 1 to 15 and Comparative Examples 1 to 10 contained 0.18 mass% of colloidal silica having an average primary particle diameter of 25 nm as the particle component, 0.005 mass% of ammonia as the basic compound, and 0.01 mass% of hydroxyethyl cellulose having a weight-average molecular weight of 250,000 as the wetting agent, and had a pH adjusted to 10.2. The average primary particle diameter values ​​of the colloidal silica were determined using a FlowSorb II 2300 surface area determination device manufactured by Micromeritics Instrument Corporation.The sum of the content of the first surfactant and the content of the second surfactant in each of the surface treatment compositions, and the ratio of the total number of carbon atoms of the second surfactant to the sum of the total number of carbon atoms of the first surfactant and the total number of carbon atoms of the second surfactant are also shown in Table 1.

[0069] The surfaces of the silicon wafers were polished under the conditions described in Table 2 with the respective surface treatment compositions of Examples 1 to 15 and Comparative Examples 1 to 10. The silicon wafers used had a disk shape, with a diameter of 200 nm, p-conduction, a crystal orientation of <100> and a resistance of 0.1 Ω cm or more and less than 100 Ω cm. The silicon wafers were used after preliminary polishing with a polishing slurry (brand name GLANZOX 1104) manufactured by Fujimi Incorporated.

[0070] The surfaces of the silicon wafers polished using the respective surface treatment compositions of Examples 1 to 15 and Comparative Examples 1 to 10 were measured by a wafer inspection device "Surfscan SP2" manufactured by KLA Tencor Corporation in DWO mode. The results of the inspection of the haze levels of the surfaces of the polished silicon wafers based on the measurement are shown in the "Haze" column in Table 1. In the column, "A" indicates that the haze level was reduced by 10% or more compared with Comparative Example 2; "B" indicates that the haze level was reduced by 5% or more and less than 10%; "C" indicates that the haze level was reduced by less than 5%; and "D" indicates that no reduction in the haze level was observed compared with Comparative Example 2.

[0071] The surfaces of a silicon wafer with p-conduction, a crystal orientation of <100> , a resistance of 0.1 Ω·cm or more and less than 100 Ω·cm and a size of 50 mm 2 were preliminarily polished with polishing slurry (brand name GLANZOX 1104) manufactured by Fujimi Incorporated, and then polished under the conditions described in Table 3 with the respective surface treatment compositions of Examples 1 to 15 and Comparative Examples 1 to 10. The surfaces of the polished silicon wafers were rinsed in running water at a flow rate of 7 l / min for 10 seconds. Subsequently, the silicon wafers were vertically erected and allowed to stand. After a lapse of 30 seconds, a maximum distance between the periphery of each silicon wafer and a wet area on the silicon wafer surface was measured. The results of the wettability test of the polished silicon wafer surface, based on the measurement, are shown in the "Wettability" column in Table 1.In the column, "A" indicates that the maximum distance between the periphery of the silicon wafer and the wet area was 5 mm or less; "B" indicates that the maximum distance was more than 5 mm and 40 mm or less; and "C" indicates that the maximum distance was more than 40 mm. PEO PPO PEO Block copolymer of polyoxyethylene-polyoxypropylene C8PEO6 Polyoxyethylene (6) 2-ethylhexyl ether C10PEO5 Polyoxyethylene (5) decyl ether C10PEO10 Polyoxyethylene (10) decyl ether C12PEO15 Polyoxyethylene (15) lauryl ether C12PEO30 Polyoxyethylene (30) lauryl ether C12PEO40 Polyoxyethylene (40) Lauryl Ether C16PEO20 Polyoxyethylene (20) cetyl ether C24PEO20 Polyoxyethylene (20) Sorbitan Monooleate PEG polyethylene glycol Table 2 Polishing machine: Single-wafer polisher PNX-322 (manufactured by Okamoto MachineTool Works, Ltd.) Polishing load: 15 kPa Rotation speed of the surface plate: 30 revolutions per minute Rotation speed of the head: 30 revolutions per minute Polishing time: 4 minutes Temperature of the surface treatment composition 20°C Feed rate of the surface treatment composition 0.5 I / min (continuous delivery without circulation) Table 3 Polishing device: Belt-type polishing device EJ-380IN (manufactured by Engis Japan Corporation) Polishing load: 15 kPa Rotation speed of the surface plate: 30 revolutions per minute Rotation speed of the head: 30 revolutions per minute Polishing time: 1 minute Temperature of the surface treatment composition 20 °C Feed rate of the surface treatment composition 0.25 I / min (continuous delivery without circulation)

[0072] As shown in Table 1, it was found that the turbidity levels of Examples 1 to 15 are lower than those of Comparative Examples 1 to 10.< / benetzungsmittel> < / partikelbestandteil> < / wasser>

Claims

[1] A surface treatment composition comprising a first surfactant, a second surfactant, a basic compound, and water, the surface treatment composition having a pH of 8 or more, the second surfactant having a weight-average molecular weight of one half or less of the weight-average molecular weight of the first surfactant, a sum of a content of the first surfactant and a content of the second surfactant being 0.00001 to 0.1 mass%, and a ratio of a total number of carbon atoms of the second surfactant to a sum of a total number of carbon atoms of the first surfactant and a total number of carbon atoms of the second surfactant being 1 to 90%. [2] The surface treatment composition according to claim 1, wherein the first surfactant has a weight-average molecular weight of 500 to 20,000. [3] The surface treatment composition according to claim 1 or 2, wherein both the first surfactant and the second surfactant are nonionic surfactants. [4] The surface treatment composition according to any one of claims 1 to 3, further comprising a particulate component. [5] The surface treatment composition according to claim 4, wherein the particle component is silicon dioxide. [6] The surface treatment composition according to any one of claims 1 to 5, further comprising a wetting agent. [7] Use of the surface treatment composition according to any one of claims 1 to 6 in an application in which a silicon wafer is subjected to a surface treatment. [8] Use of the surface treatment composition according to any one of claims 1 to 6, in an application for polishing or rinsing a surface of a substrate. [9] A kit for preparing the surface treatment composition according to any one of claims 1 to 6, wherein the kit comprises a first surfactant, a second surfactant having a weight-average molecular weight of one half or less of the weight-average molecular weight of the first surfactant, and a basic compound, and wherein a ratio of the total number of carbon atoms of the second surfactant to a sum of a total number of carbon atoms of the first surfactant and the total number of carbon atoms of the second surfactant is 1 to 90%, wherein the first surfactant has a weight-average molecular weight of 500 to 20,000. [10] A surface treatment method comprising polishing, washing, rinsing or etching a surface of a substrate using the surface treatment composition according to any one of claims 1 to 6. [11] The surface treatment method according to claim 10, wherein the substrate is a silicon wafer.