TW201742138A - Set of compositions for polishing, pre-polishing composition, and method of polishing silicon wafer - Google Patents

Abstract

Provided is a set of compositions for polishing with which it is possible to achieve a high-quality polished surface by reducing haze. This set of compositions for polishing is provided with: a finish polishing composition to be used in a finish polishing step of finish polishing a silicon wafer; and a pre-polishing composition to be used in a pre-polishing step, which is a polishing step preformed one step prior to the finish polishing step. A hydrophilicity parameter P1 of the pre-polishing composition, obtained from a standard test 1, is less than 100; a finishing accuracy parameter P2 of the pre-polishing composition, obtained from a standard test 2, is at most equal to 1000; and a polishing processability parameter F1 of the finish polishing composition, obtained from a standard test 3, is at most equal to 80.

Description

Grinding composition kit, pre-polishing composition, and polishing method of tantalum wafer

The present invention relates to a polishing composition set, a front polishing composition, and a polishing method for a tantalum wafer.

In order to reduce the turbidity of the surface of the tantalum wafer, various proposals have been made regarding the polishing composition and the polishing method (for example, refer to Patent Documents 1 and 2). However, in recent years, the level of requirements for the surface quality of germanium wafers has been gradually increased, and further improvements in such technologies are required.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 5204960

Patent Document 2: Japanese Patent Publication No. 185672, 2015

In order to solve the problems of the prior art described above, an object of the present invention is to provide a polishing composition set for polishing a surface that can reduce turbidity and to achieve high quality, and a pre-polishing composition and a silicon wafer. Grinding method.

In order to solve the above problems, the gravitational composition kit of one aspect of the present invention has a finishing polishing composition for use in a finishing polishing step for finishing a tantalum wafer, and is used for fine polishing. In the polishing composition set of the polishing composition before the pre-grinding step of the grinding step before the grinding step, the hydrophilicity parameter P1 of the polishing composition before the standard test 1 is less than 100, the standard test The finishing precision parameter P2 of the polishing composition before the determination is 2 or less, and the polishing processability parameter F1 of the finishing polishing composition obtained in the standard test 3 is 80 or less.

Further, the other aspect of the composition for polishing of the present invention is to use a composition for polishing in a polishing composition before a pre-grinding step of a polishing step of a stage prior to the finishing polishing step of the enamel wafer. The hydrophilicity parameter P1 obtained by 1 is less than 100, and the precision precision parameter P2 obtained by the standard test 2 is 1000 or less.

In addition, the gravitational method of the wafer of the other aspect of the present invention is characterized in that a finishing polishing step for finishing the silicon wafer and a pre-grinding step for the polishing step before the finishing polishing step are provided. In the polishing method of the wafer, the polishing composition using the above aspect is used. The kit is subjected to a finishing grinding step and a pre-grinding step, and a pre-grinding step is performed using the polishing composition before the other aspects described above.

By the present invention, it is possible to reduce the turbidity and realize a high-quality surface to be polished.

Form of implementing the invention

An embodiment of the present invention will be described in detail below. The polishing composition kit of the present embodiment is provided with a finishing polishing composition for finishing polishing and polishing a tantalum wafer, and a polishing step for use in a stage before the finishing polishing step. The composition for polishing before the pre-grinding step. Next, the hydrophilicity parameter P1 of the polishing composition obtained in the standard test 1 is less than 100, and the precision of the finishing precision P2 of the polishing composition before the standard test 2 is 1000 or less, and the standard test 3 is required. The polishing processability parameter F1 of the composition for finishing polishing is 80 or less.

Further, the polishing composition before the present embodiment is a polishing composition used in the polishing step before the polishing step in the first step before the finishing polishing step of finishing the polishing of the tantalum wafer. Further, the hydrophilicity parameter P1 obtained in the standard test 1 is less than 100, and the precision precision parameter P2 obtained in the standard test 2 is 1000 or less.

The polishing composition kit and the pre-polishing composition of the present embodiment are suitable for polishing a monomer, a ruthenium compound, a metal, a ceramic, or the like. Various polishing objects can realize a high-quality surface to be polished having a low turbidity, and it is also possible to realize a surface to be polished having a small number of defects, in particular, the use of the polishing composition kit or the front polishing of the present embodiment. When the composition is polished to a silicon wafer, a germanium wafer such as a single crystal wafer having a high-quality surface having a low turbidity can be produced.

In detail, in order to realize a high-quality polished surface having a low turbidity, it is important to use a finishing polishing composition which is capable of producing a high-precision polished surface with a high degree of workability. Therefore, it is necessary to make the surface to be polished after the end of the pre-polishing step a surface having moderate surface protection and good quality (low turbidity). In other words, in order to perform polishing before the surface to be polished after the completion of the pre-polishing step is a surface having appropriate surface protection and good quality, it is possible to form a surface having a surface protective property that is not excessively high and has a certain degree of good quality. The load on the polishing step is reduced, and the workability is low, and the finishing polishing composition for the polished surface with high precision can be produced for finishing polishing. Thereby, a high-quality surface to be polished having a low turbidity can be achieved. It is preferred that the surface to be polished after the end of the pre-grinding step has a higher quality.

For the above reasons, the pre-polishing composition is required to have a polishing property such that the surface to be polished after the completion of the pre-polishing step is a surface having moderate hydrophilicity and good quality. The hydrophilicity of the surface to be polished after the end of the pre-grinding step is represented by the hydrophilicity parameter P1, which can be obtained by Standard Test 1. Further, the polishing performance of the pre-polishing composition is expressed by the finishing precision parameter P2, which can be obtained by the standard test 2.

Further, since it is required to process the polishing composition to process the surface to be polished with high precision, it is necessary to suppress the workability to be low. The polishing processability of the finishing polishing composition is represented by a polishing process parameter F1, which can be obtained by the standard test 3.

The standard test 1, 2, and 3 for obtaining the hydrophilicity parameter P1, the finishing precision parameter P2, and the grinding processability parameter F1 are as follows.

Further, the pre-grinding step of the present invention refers to a grinding step of a stage before the finishing of the lapping step in the plurality of grinding steps of the rubbing method of the crucible wafer. Therefore, the polishing method of the silicon wafer is, for example, three polishing steps including a first polishing step, a second polishing step, and a finishing polishing step of the preliminary polishing step, and the front polishing step corresponds to the second polishing step. Further, the polishing method of the ruthenium wafer is, for example, the two polishing steps of the first polishing step and the finishing polishing step of the preliminary polishing step, and the front polishing step corresponds to the first polishing step.

The polishing composition, the finishing polishing composition, and the polishing composition before the present embodiment will be described in detail below. Further, the various operations and physical property measurement methods described below are carried out under the conditions of room temperature (20° C. or higher and 25° C. or lower) and relative humidity of 40% or more and 50% or less, unless otherwise specified.

1. About the former polishing composition

The polishing composition before the polishing step is used. The hydrophilicity parameter P1 obtained in the standard test 1 is less than 100, and the precision precision parameter P2 obtained in the standard test 2 is 1000 or less. Will be explained below Standard Tests 1 and 2.

1-1 Relevant standard test 1

The hydrophilicity parameter P1 was determined by sequentially performing the standard test 1 of the following steps a1, a2, a3, and a4.

[Standard Test 1]

(a1) A test piece of the same material as the tantalum wafer of the object to be polished is polished by using the composition for polishing before use. The ruthenium test piece can be used as a round wafer or as a quadrangular sheet. When the ruthenium test piece is ground, for example, a table grinder EJ-380IN manufactured by Nippon Co., Ltd., and a polishing table POLYPAS27 NX manufactured by Fujie Pang Co., Ltd. can be used. Further, the polishing conditions of the polishing flaw test piece may be, for example, a polishing load of 16 kPa, a chassis rotation speed of 30 rpm, a carrier rotation speed of 30 rpm, a polishing time of 2 minutes, a supply rate of the pre-polishing composition of 30 mL/min, and a temperature of the pre-polishing composition. 20 ° C.

(a2) The surface of the ruthenium test piece to be polished was washed with pure water to clean the composition before polishing.

(a3) When the test piece is circular, the diameter is in the vertical direction, and when the test piece is square, the diagonal line is oriented in the vertical direction, and the pure water is left to be washed. After 30 seconds, the length of the field in which the surface of the ruthenium test piece in the diameter or one of the diagonals was not wetted by pure water was measured, and the length was used as the drainage distance.

(a4) From the measured drainage distance, the hydrophilicity parameter P1 of the pre-polishing composition was calculated based on the following formula.

Hydrophilic parameter P1={(the diameter of the test piece or the length of the diagonal line [mm]) - (drainage distance [mm])} / (the diameter of the test piece or the length of the diagonal line [mm]) × 100

1-2 Relevant standard test 2

The finishing precision parameter P2 is obtained by sequentially performing the following b1 step, b2 step and b3 step standard test 2.

[Standard Test 2]

(b1) A wafer test piece (that is, a wafer for measurement parameters) of the same material as the wafer of the object to be polished is polished before use. For the polishing of the ruthenium wafer test piece, for example, a grinder PNX-332B manufactured by Okamoto Machine Works Co., Ltd., and a polishing table POLYPAS27NX manufactured by Fujimoto Co., Ltd. can be used. Moreover, the polishing conditions of the polished silicon wafer test piece may be, for example, a polishing load of 15 kPa, a flat plate rotation speed of 30 rpm, a carrier rotation speed of 30 rpm, a polishing time of 2 minutes, a supply rate of the front polishing composition of 2 L/min, and a pre-polishing composition. The temperature is 20 ° C, and the temperature of the flat cooling water is 20 ° C.

(b2) A silicon wafer test piece of the same material as the tantalum wafer of the object to be polished is polished using the standard polishing composition. For the polishing of the ruthenium wafer test piece, for example, a grinder PNX-332B manufactured by Okamoto Machine Works Co., Ltd., and a polishing table POLYPAS27NX manufactured by Fujimoto Co., Ltd. can be used. Further, the polishing conditions of the polished silicon wafer test piece may be, for example, a polishing load of 15 kPa, a flat plate rotation speed of 30 rpm, and a carrier rotation. The speed was 30 rpm, the polishing time was 2 min, the supply rate of the standard polishing composition was 2 L/min, the temperature of the standard polishing composition was 20 ° C, and the temperature of the flat cooling water was 20 °C.

The standard polishing composition is a hydroxyethyl cellulose having a mean primary particle diameter of 35 nm of 0.46 mass%, an ammonia content of 0.009% by mass, a weight average molecular weight of 250,000 hydroxyethylcellulose, and 0.017 mass%, and a polyethylene oxide and a polyethylene oxide. The copolymer formed of polypropylene oxide was 0.002% by mass, and the residue was water.

(b3) Measure the turbidity h2 of the ruthenium wafer test piece after the b1 step polishing, and the turbidity α of the ruthenium wafer test piece after the b2 step polishing, and calculate the finishing precision of the pre-polishing composition based on the following formula Parameter P2.

Finishing precision parameter P2=h2/α×100

2. Composition for finishing grinding

The finishing polishing composition used in the finishing polishing step of the wafer is such that the polishing processability parameter F1 obtained in the standard test 3 is 80 or less, and the polishing process parameter F1 is sequentially performed in the following c1 step, c2 The standard test 3 of the step and the c3 step is obtained.

[Standard Test 3]

(c1) The 试验 wafer test piece of the same material as the 矽 wafer of the object to be polished is polished by the finishing polishing composition, and the pulverizer PNX manufactured by Okamoto Machine Tool Co., Ltd. can be used, for example, when the ruthenium wafer test piece is polished. -322, grinding table POLYPAS27NX made by Fujikeng Co., Ltd. also, The polishing conditions of the polished silicon wafer test piece may be, for example, a polishing load of 15 kPa, a flat plate rotation speed of 30 rpm, a carrier rotation speed of 30 rpm, a polishing time of 15 minutes, a supply speed of a finishing polishing composition of 0.4 L/min, and a finishing polishing composition. The temperature of the object was 20 ° C, and the temperature of the plate cooling water was 20 ° C.

(c2) A silicon wafer test piece of the same material as the tantalum wafer of the object to be polished was polished using the standard polishing composition of Standard Test 2. For the polishing of the tantalum wafer test piece, for example, a grinder PNX-322 manufactured by Okamoto Machine Works Co., Ltd., and a polishing table POLYPAS27NX manufactured by Fujie Pang Co., Ltd. can be used. Further, the polishing conditions of the polished silicon wafer test piece may be, for example, a polishing load of 15 kPa, a flat plate rotation speed of 30 rpm, a carrier rotation speed of 30 rpm, a polishing time of 15 minutes, a supply rate of a standard polishing composition of 0.4 L/min, and a standard polishing composition. The temperature of the object was 20 ° C, and the temperature of the plate cooling water was 20 ° C.

(c3) Calculating the polishing rate R during the polishing in the c1 step from the difference in the mass of the wafer test piece before and after the polishing in the step c1, and calculating the mass difference of the wafer test piece before and after the polishing in the c2 step. Grinding speed β. Next, the polishing processability parameter F1 of the finishing polishing composition is calculated based on the following formula.

Grinding processability parameter F1=R/β×100

3. About the composition of the polishing composition

Since the polishing composition kit of the present embodiment has a pre-polishing composition and a finishing polishing composition, two or more polishing steps can be used. For the polishing method of the wafer, for example, a method of polishing a tantalum wafer provided with a first grinding step of a preliminary grinding step and a finishing step of a finishing grinding step, or a preliminary grinding step may be used. A method of grinding a tantalum wafer of three grinding steps of a first grinding step, a second grinding step, and a finishing grinding step.

When the polishing method for the tantalum wafer having three or more kinds of polishing steps is the use of the polishing composition kit of the present embodiment, the finishing polishing step can use the finishing polishing composition of the present embodiment, before the finishing polishing step In the pre-polishing step of the one-step polishing step, the polishing composition before the present embodiment can be used, and the polishing composition suitable for the polishing step can be appropriately selected for each of the polishing steps.

Next, the components constituting the finishing polishing composition and the pre-polishing composition of the present embodiment will be described. The finishing polishing composition and the pre-polishing composition of the present embodiment each contain a composition of abrasive grains, a basic compound, a water-soluble polymer, and water. It can also contain various additives as desired.

4. About abrasive particles

The abrasive particles have the function of physically grinding the surface of the wafer. The type of the abrasive grains is not particularly limited, and examples thereof include cerium oxide particles, alumina particles, cerium oxide particles, chromium oxide particles, titanium oxide particles, zirconia particles, magnesium oxide particles, manganese dioxide particles, zinc oxide particles, and iron oxide red particles. Oxide particles, or nitride particles such as tantalum nitride particles or boron nitride particles, or carbide particles such as niobium carbide particles or boron carbide particles, or carbonic acid Carbonate such as calcium or barium carbonate, or diamond particles.

Among these specific examples, cerium oxide is preferred. Specific examples of the cerium oxide include cerium oxide particles selected from colloidal cerium oxide, fumed cerium oxide, and sol-gel cerium oxide. The cerium oxide particles reduce the scratching of the polished surface of the germanium wafer, preferably the cerium oxide particles selected from the colloidal cerium oxide and the fumed cerium oxide, and particularly preferably the colloidal smear. Yttrium oxide. The abrasive grains may be used alone or in combination of two or more.

The average primary particle diameter of the abrasive grains used in the pre-polishing composition is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 15 nm or more, and particularly preferably 20 nm or more. By increasing the average primary particle size of the abrasive particles, the polishing speed of the tantalum wafer can be increased. Further, the average primary particle diameter of the abrasive grains used in the pre-polishing composition is preferably 100 nm or less, more preferably 60 nm or less, still more preferably 50 nm or less. By reducing the average primary particle size of the abrasive particles, the smoothness of the surface to be polished can be improved.

The average primary particle diameter of the abrasive grains used for the finishing polishing composition is preferably 5 nm or more, and more preferably 10 nm or more. By increasing the average primary particle size of the abrasive particles, the polishing speed of the tantalum wafer can be increased. Further, the average primary particle diameter of the abrasive grains used for the finishing polishing composition is preferably 100 nm or less, more preferably 60 nm or less, still more preferably 50 nm or less, and particularly preferably 40 nm or less. By reducing the average primary particle size of the abrasive particles, the smoothness of the surface to be polished can be improved.

Further, the average primary particle diameter of the abrasive grains used in the pre-polishing composition and the finishing polishing composition can be measured by the BET method. The specific surface area of the particles was calculated. The specific surface area of the abrasive grains can be measured, for example, using the type "Flow Sorbll 2300" manufactured by McGraw.

The average secondary particle diameter of the abrasive grains used in the pre-polishing composition is preferably 10 nm or more, more preferably 20 nm or more, still more preferably 30 nm or more, and particularly preferably 40 nm or more. By increasing the average secondary particle size of the abrasive particles, the polishing speed of the silicon wafer can be increased. Further, the average secondary particle diameter of the abrasive grains used in the pre-polishing composition is preferably 150 nm or less, more preferably 100 nm or less, still more preferably 80 nm or less, and particularly preferably 70 nm or less. By reducing the average secondary particle size of the abrasive particles, the smoothness of the surface to be polished can be improved.

The average secondary particle diameter of the abrasive grains used for the finishing polishing composition is preferably 10 nm or more, and more preferably 20 nm or more. By increasing the average secondary particle size of the abrasive particles, the polishing speed of the silicon wafer can be increased. Further, the average secondary particle diameter of the abrasive grains used for the finishing polishing composition is preferably 100 nm or less, more preferably 80 nm or less, still more preferably 70 nm or less, and particularly preferably 60 nm or less. By reducing the average secondary particle size of the abrasive particles, the smoothness of the surface to be polished can be improved.

In addition, the average secondary particle diameter value of the abrasive grains used for the pre-polishing composition and the finishing polishing composition can be measured, for example, by a dynamic light scattering method using UPA-UT151 manufactured by Nikkiso Co., Ltd.

The content of the abrasive grains in the pre-polishing composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.10% by mass or more. When the content of the abrasive grains is within the above range, the ruthenium wafer can have an excellent polishing rate.

The content of the abrasive grains in the pre-polishing composition is preferably 3% by mass or less. Further, it is preferably 1% by mass or less, more preferably 0.5% by mass or less. When the content of the abrasive grains is within the above range, the dispersion stability of the composition for pre-polishing can be improved.

The content of the abrasive grains in the composition for finishing polishing is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.10% by mass or more. When the content of the abrasive grains is within the above range, the ruthenium wafer can have an excellent polishing rate.

The content of the abrasive grains in the composition for finishing polishing is preferably 3% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less, and particularly preferably 0.3% by mass or less. When the content of the abrasive grains is within the above range, the dispersion stability of the composition for finishing polishing can be improved.

5. About basic compounds

The composition for polishing and the composition for pre-polishing contain a basic compound. The alkaline compound can be chemically polished (chemically etched) by imparting a chemical action to the surface to be polished of the tantalum wafer. This makes it easy to increase the polishing speed when polishing the silicon wafer.

Specific examples of the basic compound include inorganic basic compounds, hydroxides or salts of alkali metal or alkaline earth metals, quaternary ammonium hydroxide or salts thereof, ammonia, amines and the like. Specific examples of the alkali metal include potassium, sodium, and the like. Specific examples of the salt include carbonate, hydrogencarbonate, sulfate, acetate, and the like. Specific examples of the quaternary ammonium are, for example, tetramethylammonium, tetraethylammonium, tetrabutylamine and the like. Specific examples of the hydroxide or salt of the alkali metal include potassium hydroxide, potassium carbonate, potassium hydrogencarbonate, potassium sulfate, potassium acetate, potassium chloride and the like.

Specific examples of the quaternary ammonium hydroxide or a salt thereof include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide and the like. Specific examples of the amine are, for example, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylidene diamine, monoethanolamine, N-(β-amino group B Ethylamine, hexamethylenediamine, di-ethyltriamine, tri-ethyltetramine, piperazine anhydride, piperazine hexahydrate, 1-(2-aminoethyl)piperazine, N- An azole such as methyl piperazine, vein, imidazole or triazole. These basic compounds may be used alone or in combination of two or more.

The basic compound is preferably at least one selected from the group consisting of ammonia, an ammonium salt, an alkali metal hydroxide, an alkali metal salt, and a quaternary ammonium hydroxide. The basic compound is further composed of ammonia, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, ammonium hydrogencarbonate, ammonium carbonate, potassium hydrogencarbonate, potassium carbonate, sodium hydrogencarbonate and carbonic acid. At least one selected from the sodium is preferred. More preferably, the basic compound is at least one selected from the group consisting of ammonia, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide and tetraethylammonium hydroxide, and particularly preferably at least ammonia and tetramethylammonium hydroxide. One side, the best is ammonia.

The content of the basic compound in the pre-polishing composition is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, still more preferably 0.005% by mass or more, and particularly preferably 0.01% by mass or more. By increasing the content of the basic compound in the pre-polishing composition, it tends to increase the polishing rate of the tantalum wafer.

The content of the basic compound in the pre-polishing composition is preferably 0.5% by mass or less, more preferably 0.1% by mass or less, still more preferably 0.05% by mass or less. By reducing the inclusion of basic compounds in the pre-grinding composition The amount tends to improve the smoothness of the surface of the wafer after polishing.

The content of the basic compound in the composition for polishing and polishing is preferably 0.0001% by mass or more, more preferably 0.0005 mass% or more, still more preferably 0.001% by mass or more. By increasing the content of the basic compound in the finishing polishing composition, it tends to increase the polishing rate of the silicon wafer.

The content of the basic compound in the composition for finishing polishing is preferably 0.5% by mass or less, more preferably 0.1% by mass or less, still more preferably 0.05% by mass or less, and particularly preferably 0.02% by mass or less. By reducing the content of the basic compound in the finishing polishing composition, it tends to improve the smoothness of the surface of the wafer after polishing.

6. About water soluble polymers

When the water-soluble polymer is subjected to surface treatment such as polishing or cleaning, the wettability of the polished surface of the tantalum wafer can be improved. The composition for polishing and the composition for pre-polishing is a water-soluble material which is solid or solid-formed into a solid raw material when it is used as a composition for polishing a water-soluble polymer and a composition for a pre-honing composition. Polymer.

The solid raw material means a substance which is visually solid or solid in an environment of a temperature of 23 ° C, a relative humidity of 50% and a pressure of 1 ° before being dissolved in water. Further, the water-soluble polymer may be a product synthesized from a monomer in water, a mixed solvent of water and an aqueous organic solvent such as an alcohol or a ketone, or a form of an aqueous liquid directly in the form of the solution, or may be distilled off. The form of the aqueous solution after the volatile solvent. In addition, the following are "water-soluble polymers of solid raw materials", "water-soluble polymers in water form", and "aqueous solutions". The water-soluble polymer of the form is simply referred to as "water-soluble polymer".

The water-soluble polymer is one having at least one functional group selected from the group consisting of a cationic group, an anionic group and a nonionic group in the molecule, and specifically, a molecule having a hydroxyl group, a carboxyl group, a decyloxy group, a sulfo group or a fluorene group may also be used. Any one of an amine group, a mercapto group, an imido group, a quinone imine group, a quaternary nitrogen structure, a heterocyclic structure containing the aforementioned functional unit, a vinyl structure, a polyalkylene oxide structure or the like.

Specifically, for example, a fiber-based derivative, polyvinyl alcohol, poly(meth)acrylic acid, poly(meth)acrylamide-alkylsulfonic acid, polyisoprenesulfonic acid, polyvinylsulfonic acid, polyallyl Sulfonic acid, polyisoprene sulfonic acid, polystyrene sulfonate, poly(meth) acrylamide, polyalkylaminoalkyl (meth) acrylamide, polyvinyl pyrrolidone, partial structure a copolymer containing polyvinylpyrrolidone, polyvinyl caprolactam, a copolymer having a partial structure containing polyvinyl caprolactam, a polyalkoxyalkyl (meth) acrylamide, a polyhydroxyalkyl group ( Methyl) acrylamide, poly(meth)propenyl morpholine, polyfluorene, polyethylenimine, hydrophilic polyimine, various polyamino acids, poly(N-fluorenylalkylene) An imine derivative such as an amine, a polyvinyl alcohol derivative in which a part of a hydroxyl group of the polyvinyl alcohol is substituted with a four-stage nitrogen structure, a polyethylene oxide, a polymer having a polyoxyalkylene structure, and the like Diblock, triblock, random or interactive polymers of a plurality of structures. Further, poly(meth)acrylic acid means acrylic acid and/or methacrylic acid, and other compounds are also the same.

In the water-soluble polymer, the wettability of the polished surface of the germanium wafer is improved, the adhesion of the microchip is suppressed, and the surface roughness is lowered. Preferred are cellulose derivatives, polyvinyl alcohol, polyvinyl pyrrolidone, polyhydroxyalkyl (meth) acrylamide, poly(meth) propylene decyl morpholine, or a polymer having a polyoxy olefin structure. Specific examples of the cellulose derivative are, for example, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, methylcellulose, ethylcellulose, ethylhydroxyl Cellulose, carboxymethylcellulose, and the like.

Among the cellulose derivatives, the ability to impart wettability to the surface to be polished of the wafer is improved, and from the viewpoint of good detergency, hydroxyethyl cellulose is particularly preferable. Further, the water-soluble polymers may be used alone or in combination of two or more.

The weight average molecular weight of the water-soluble polymer used in the pre-polishing composition is preferably 10,000 or more, more preferably 20,000 or more, still more preferably 30,000 or more. The weight average molecular weight of the water-soluble polymer tends to increase the polishing rate of the silicon wafer.

The weight average molecular weight of the water-soluble polymer used in the pre-polishing composition is preferably 2,000,000 or less, more preferably 1.5 million or less, more preferably 1.2 million or less, still more preferably 1,000,000 or less, and particularly preferably 70. Less than 10,000. By reducing the weight average molecular weight of the water-soluble polymer, it tends to further maintain the stability of the pre-polishing composition. Further, it tends to lower the turbidity of the surface to be polished of the germanium wafer.

The water-soluble polymer used for the finishing polishing composition preferably has a weight average molecular weight of 10,000 or more, more preferably 20,000 or more, still more preferably 30,000 or more. By increasing the weight average molecular weight of the water-soluble polymer, it tends to increase the polishing rate of the silicon wafer.

The weight average molecular weight of the water-soluble polymer used for the finishing polishing composition is preferably 2,000,000 or less, more preferably 1.5 million or less, more preferably 1.2 million or less, and even more preferably 1,000,000 or less. The best is less than 800,000, and the best is less than 600,000, and the best is less than 300,000. By reducing the weight average molecular weight of the water-soluble polymer, it is preferable to further maintain the stability of the composition for finishing polishing. Further, it tends to lower the turbidity of the surface to be polished of the germanium wafer.

The content of the water-soluble polymer in the pre-polishing composition is preferably 0.0001% by mass or more, more preferably 0.0005 mass% or more, still more preferably 0.001% by mass or more. By increasing the content of the water-soluble polymer in the pre-polishing composition, it tends to further improve the wettability of the surface to be polished of the tantalum wafer.

The content of the water-soluble polymer in the pre-polishing composition is preferably 0.5% by mass or less, more preferably 0.1% by mass or less, still more preferably 0.05% by mass or less, still more preferably 0.01% by mass or less, and particularly preferably 0.005%. Below mass%. By reducing the content of the water-soluble polymer in the pre-polishing composition, it is preferable to further maintain the stability of the pre-polishing composition.

The content of the water-soluble polymer in the finishing polishing composition is preferably 0.0001% by mass or more, more preferably 0.0005 mass% or more, still more preferably 0.001% by mass or more, and particularly preferably 0.005% by mass or more. By increasing the content of the water-soluble polymer in the composition for finishing polishing, it tends to further improve the wettability of the surface to be polished of the tantalum wafer.

The content of the water-soluble polymer in the composition for finishing polishing is preferably 0.5% by mass or less, more preferably 0.1% by mass or less, more preferably It is more preferably 0.05% by mass or less and further preferably 0.01% by mass or less. By reducing the content of the water-soluble polymer in the composition for finishing polishing, it is preferable to further maintain the stability of the composition for finishing polishing.

The mass ratio of the abrasive grains, the water-soluble polymer, and the basic compound in the composition for polishing and the pre-polishing composition may be 50 to 99: 0.5 to 20: 0.5 to 30. When the mass ratio of the content is within this range, the dispersion stability of the composition for polishing and the composition for pre-polishing can be improved, and the cleanness of the wafer after washing can be improved.

7. The pH of the finishing polishing composition and the pre-polishing composition

The pH of the pre-polishing composition is not particularly limited, but is preferably 9.0 or more, more preferably 9.5 or more, still more preferably 10.0 or more. By increasing the pH, it tends to increase the polishing speed of the wafer.

The pH of the pre-polishing composition is preferably 11.5 or less, more preferably 11.0 or less, still more preferably 10.8 or less, and the pH is lowered to increase the surface accuracy of the wafer.

The pH of the finishing polishing composition is not particularly limited, but is preferably 9.0 or more, more preferably 9.5 or more, still more preferably 9.8 or more. By increasing the pH, it tends to increase the polishing speed of the wafer.

The pH of the finishing polishing composition is preferably 11.5 or less, more preferably 11.0 or less, still more preferably 10.5 or less. By lowering the pH, it tends to increase the accuracy of the wafer surface. The pH of the composition for polishing and the composition for pre-polishing can be adjusted by, for example, adding a pH adjuster described later.

8. About water

The water system is used as a dispersing agent or solvent for other components such as abrasive grains, basic compounds, and water-soluble polymers. In order to prevent the action of the finishing polishing composition and the other components contained in the pre-polishing composition as much as possible, the water preferably has a total content of the transition metal ions of, for example, 100 ppb or less. For example, an ion exchange resin can be used to remove impurities ions, particles are removed by a filter, and distillation or the like can be used to increase the purity of water. Specifically, ion-exchanged water, pure water, ultrapure water, distilled water or the like is preferably used.

9. Related additives

In order to improve the performance, the finishing polishing composition and the pre-polishing composition of the present embodiment may be added with various additives such as a pH adjuster, a surfactant, a chelating agent, and a mold inhibitor. However, it is preferred that the oxidant is substantially absent.

9-1 About pH adjuster

The pH of the finishing polishing composition and the pre-polishing composition of the present embodiment can be adjusted by adding a pH adjusting agent. By adjusting the pH of the finishing polishing composition and the pre-polishing composition, the polishing rate of the object to be polished, the dispersibility of the abrasive grains, and the like can be controlled. The amount of the pH adjuster to be added is not particularly limited, and can be appropriately adjusted depending on the desired pH of the finishing polishing composition and the pre-polishing composition.

Specific examples of the pH adjuster include inorganic acids or organic acids such as carboxylic acids and organic sulfuric acids. Specific examples of inorganic acids, for example, hydrochloric acid, sulfuric acid, nitric acid, Fluoric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, phosphoric acid, and the like. Further, specific examples of the carboxylic acid are formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, amber Acid, glutaric acid, adipic acid, pimelic acid, maleic acid, citric acid, malic acid, tartaric acid, citric acid, lactic acid, diglycolic acid, 2-furancarboxylic acid, 2,5-furandicarboxylic acid , 3-furancarboxylic acid, 2-tetrahydrofurancarboxylic acid, methoxyacetic acid, methoxyphenylacetic acid, phenoxyacetic acid, and the like. Further, specific examples of the organic sulfuric acid include methanesulfonic acid, ethanesulfonic acid, isethionic acid, and the like. These acids may be used alone or in combination of two or more.

9-2 related surfactants

A surfactant can be added to the finishing polishing composition and the pre-polishing composition of the present embodiment. A surfactant such as an anionic or nonionic surfactant is preferred as the nonionic surfactant.

For example, an oxyalkylene polymer such as polyethylene glycol, polypropylene glycol, or polytetramethylene glycol, or a polyethylene oxide alkyl ether, a polyethylene oxide alkyl phenyl ether, or a polyethylene oxide alkane. a polyalkylene oxide adduct of a base amine, a polyethylene oxide fatty acid ester, a polyethylene oxide glyceryl ether fatty acid ester, a polyethylene oxide sorbitol fatty acid ester, or a plurality of alkane A nonionic surfactant such as an alcohol copolymer (diblock type, triblock type, random type, interactive type).

Specific examples of the nonionic surfactant are, for example, oxyethylene Block copolymer of (EO) and oxypropylene (PO) (diblock, PEO-PPO-PEO type triblock, PPO-PEO-PPO type triblock, etc.), EO and PO Copolymer, polyoxyethylene glycol, polyethylene oxide propyl ether, polyethylene oxide butyl ether, polyethylene oxide pentyl ether, polyethylene oxide hexyl ether, polyethylene oxide Alkyl octyl ether, polyethylene oxide-2-ethylhexyl ether, polyethylene oxide decyl ether, polyethylene oxide decyl ether, polyethylene oxide isodecyl ether, polyethylene oxide Alkyl tridecyl ether, polyethylene oxide lauryl ether, polyethylene oxide cetyl ether, polyethylene oxide stearyl ether, polyethylene oxide isostearyl ether, polycyclic ring Oxyethane ethane alkenyl ether, polyethylene oxide phenyl ether, polyethylene oxide octyl phenyl ether, polyethylene oxide nonylphenyl ether, polyethylene oxide dodecyl phenyl Ether, polyethylene oxide styrenated phenyl ether, polyethylene oxide laurylamine, polyethylene oxide stearylamine, polyethylene oxide oleylamine, polyethylene oxide stearin Amine, polyethylene oxide oleylamine, polyethylene oxide monolaurate, polyethylene oxide monostearate, poly Ethoxyethane distearate, polyethylene oxide monooleate, polyethylene oxide dioleate, monolaurate polyethylene oxide sorbitan, monopalmitate polyethylene oxide Sorbitol, monostearate polyethylene oxide sorbitan, monooleic acid polyethylene oxide sorbitan, trioleic acid polyethylene oxide sorbitan, tetraoleic acid polycyclic ring Oxygen ethane sorbitan, polyethylene oxide castor oil, polyethylene oxide hardened castor oil, and the like. Among the preferred surfactants are block copolymers of EO and PO (especially PEO-PPO-PEO type triblocks), random copolymers of EO and PO, and polyethylene oxide alkyl ethers ( For example, polyethylene oxide decyl ether).

Also, an anionic surfactant such as polyethylene oxide Sulfates and their salts, sulfonic acids and salts thereof, carboxylic acids and salts thereof, and phosphates and salts thereof.

Specific examples of the anionic surfactant are, for example, polyethylene oxide lauryl ether sulfuric acid, polyethylene oxide myristyl ether sulfuric acid, polyethylene oxide palmityl ether sulfuric acid; polyethylene oxide lauryl ether sulfate , polyethylene oxide ammonium lauryl ether sulfate, polyethylene oxide lauryl ether triethanolamine sulfate, polyethylene oxide myristyl ether sulfate, polyethylene oxide myristyl ether ammonium sulfate, polycyclic ring Oxygen ethane myristyl ether triethanolamine sulfate, polyethylene oxide palmitate sodium sulfate, polyethylene oxide palmityl ether sulfate, polyethylene oxide palmityl ether triethanolamine, polyethylene oxide Octyl sulfonic acid, polyethylene oxide dodecyl sulfonic acid, polyethylene oxide hexadecyl sulfonic acid, polyethylene oxide octyl benzene sulfonic acid, polyethylene oxide hexadecyl benzene Sulfonic acid; sodium polyoxyethylene octyl sulfonate, sodium polyethylene oxide dodecyl sulfonate, sodium polyethylene oxide hexadecyl sulfonate, polyethylene oxide lauryl ether acetic acid, Polyethylene oxide lauryl ether acetate, polyethylene oxide octyl ether acetic acid; polyethylene oxide lauryl ether acetate sodium, polyethylene oxide lauryl Ammonium acetate, polyethylene oxide tridecyl ether acetate, polyethylene oxide tridecyl ether ammonium acetate, polyethylene oxide octyl ether acetate, polyethylene oxide octyl ether ammonium acetate , polyethylene oxide lauryl ether phosphate, polyethylene oxide alkyl (12-15) ether phosphate; polyethylene oxide lauryl ether sodium phosphate, polyethylene oxide oleyl ether sodium phosphate, poly Ethylene oxide cetyl ether sodium phosphate, polyethylene oxide alkyl (12-15) ether potassium phosphate, polyethylene oxide lauryl sulfosuccinate disodium salt, sulfosuccinic acid polyepoxy Ethyl lauryl mercaptoethanol guanamine disodium salt and the like.

The weight average molecular weight of the surfactant is preferably 200 Above, it is preferably 250 or more, more preferably 300 or more. By increasing the weight average molecular weight of the surfactant, the polishing speed of the tantalum wafer can be increased.

The weight average molecular weight of the surfactant is preferably less than 10,000, more preferably not more than 9,500. The smoothness of the surface to be polished can be improved by reducing the weight average molecular weight of the surfactant.

9-3 About chelating agents

A chelating agent can be added to the finishing polishing composition and the pre-polishing composition of the present embodiment. The chelating agent inhibits metal contamination of the ruthenium substrate (especially from nickel and copper) by capturing the metal impurity components in the abrasive system to form a complex.

Specific examples of the chelating agent include a carboxylic acid-based chelating agent such as glutaconic acid, an amine-based chelating agent such as ethylenediamine, di-ethyltriamine or trimethyltetramine, and ethyldiaminetetraacetic acid. Polyaminopolycarboxylic acid chelating agent such as cyanotriacetic acid, hydroxyethyl extended ethyldiaminetriacetic acid, tris-ethyltetraamine hexaacetic acid, di-extended ethyltriaminepentaacetic acid, etc., 2-amino B Phosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, amine tris(methylphosphonic acid), ethyldiamine tetra(methylphosphonic acid), diethylidene triamine Five (methyl phosphonic acid), ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, methane hydroxyphosphonic acid, 1-phosphinobutane-2,3,4 An organic phosphonic acid-based chelating agent such as a tricarboxylic acid, a phenol derivative, or a 1,3-diketone. Among these chelating agents, an organic phosphonic acid-based chelating agent is preferred, and an ethylidene diamine tetra(methylphosphonic acid) is particularly preferred. These chelating agents may be used alone or in combination of two or more.

9-4 About anti-fungal agents

In the finishing polishing composition and the pre-polishing composition of the present embodiment, an anti-fungal agent can be added. Specific examples of the fungicide include, for example, oxazolines such as 2-oxazolidine-2,5-dione.

9-5 About oxidants

The finishing polishing composition and the pre-polishing composition of the present embodiment are preferably substantially free of an oxidizing agent. When the composition for polishing and the composition for pre-polishing contains an oxidizing agent, the polishing composition is supplied to the object to be polished (for example, a tantalum wafer), and the surface of the object to be polished is oxidized to form an oxide film. It is necessary to lengthen the required grinding time. Specific examples of the oxidizing agent referred to at this time include hydrogen peroxide (H ₂ O ₂ ), sodium persulfate, ammonium persulfate, potassium permanganate, sodium dichlorotrisocyanate, and the like.

Further, the finishing polishing composition and the pre-polishing composition do not substantially contain an oxidizing agent, and at least the oxidizing agent is not intended to be contained. Therefore, it is inevitable to contain a trace amount from a raw material, a production method, etc. (for example, the molar concentration of the oxidizing agent in the composition for finishing polishing and the composition for pre-polishing is 0.0005 mol/L or less, and preferably 0.0001 mol or less, more preferably The polishing composition (finishing polishing composition, pre-polishing composition) having an oxidizing agent of 0.00001 mol/L or less, particularly preferably 0.000001 mol/L or less may be contained in the case where the oxidizing agent is substantially not contained at this time. In the concept of polishing composition.

10. Grinding method for germanium wafer

The finishing polishing composition and the front polishing group of the embodiment are used. When the wafer is polished, the wafer can be polished by a general polishing apparatus and polishing conditions. For example, a single-side polishing device or a double-side polishing device can be used.

For example, when a tantalum wafer is polished by a single-sided polishing apparatus, a flat plate with a polishing cloth is pressed against one side of the silicon wafer by using a holder called a carrier to hold the silicon wafer under the wafer, and then supplied to the substrate. In the embodiment, the polishing composition or the pre-polishing composition is rotated while rotating the chassis to polish one side of the silicon wafer.

Moreover, when the silicon wafer is polished by the double-side polishing apparatus, the wafer is attached to the wafer by using a holder called a carrier, and the flat sheets to which the polishing cloth is attached are pressed on both sides of the wafer. Thereafter, while the finishing polishing composition or the pre-polishing composition of the present embodiment is supplied, both side plates are rotated to polish both sides of the crucible wafer.

Regardless of the use of any type of polishing device, the physical action of rubbing (friction of polishing cloth and polishing composition (finishing polishing composition, pre-polishing composition) and tantalum wafer), and finishing polishing can be performed. The tantalum wafer is polished by the chemical action of the composition and the pre-polishing composition with respect to the tantalum wafer.

As the polishing cloth, various materials such as polyurethane, non-woven fabric, and flannel can be used. Further, it is also possible to use materials having different physical properties such as hardness and thickness of different materials, and it is also possible to use an abrasive-containing material or an abrasive-free material, but it is preferable to use an abrasive-free material. Further, it is also possible to use a liquid-like finishing polishing composition and a pre-polishing composition to carry out the storage of the groove.

In addition, either the finishing grinding step or the pre-grinding step The polishing load (the pressure applied to the crucible wafer) in the polishing conditions is not particularly limited, and may be 5 kPa or more and 50 kPa or less, preferably 8 kPa or more and 30 kPa or less, and more preferably 10 kPa or more and 20 kPa or less. When the polishing load is within this range, a sufficient polishing rate can be exhibited, and defects such as breakage of the ruthenium wafer due to the load and scratches on the surface of the ruthenium wafer can be suppressed.

Moreover, the relative speed (linear velocity) of the polishing cloth for polishing and the tantalum wafer in the polishing conditions is not particularly limited, and may be 10 m/min or more and 300 m/min or less, preferably 30 m/min or more and 200 m/min or less. A sufficient polishing speed is obtained when the relative speed of the polishing cloth and the silicon wafer is within this range. Further, it is possible to suppress breakage of the polishing cloth by rubbing the wafer, and to sufficiently transmit the frictional force to the silicon wafer, thereby suppressing the silicon wafer from being in a sliding state and sufficiently polishing.

Further, the amount of the finishing polishing composition and the pre-polishing composition in the polishing conditions may vary depending on the type of the wafer, the type of the polishing apparatus, and the polishing conditions, and may be between the supply of the wafer and the polishing cloth. The finishing polishing composition and the pre-polishing composition have a sufficient amount without unevenness. When the amount of the finishing polishing composition and the pre-polishing composition is small, the finishing polishing composition and the pre-polishing composition cannot be supplied to the entire wafer, and the polishing composition and the former are finished. After the polishing composition is dried and solidified, defects may occur on the surface of the germanium wafer. On the other hand, when the amount of the finishing polishing composition and the pre-polishing composition is too large, the excess finishing polishing composition and the pre-polishing composition (particularly water) may be prevented from rubbing and hinder the polishing, in addition to the economical surface.

Further, when the finishing polishing composition and the pre-polishing composition of the present embodiment are used for polishing a tantalum wafer, they can be reused for use in Grinding the germanium wafer. Further, one of the methods for finishing the polishing composition and the pre-polishing composition, for example, recovering the finishing polishing composition and the pre-polishing composition discharged from the polishing apparatus in a tank, and then recycling it back to the polishing apparatus for use in the polishing apparatus. The method of grinding. When the finishing polishing composition and the pre-polishing composition are recycled, the amount of the finishing polishing composition and the pre-polishing composition discharged in the form of waste liquid can be reduced, thereby reducing the environmental load and reducing the finishing. Since the amount of the polishing composition and the pre-polishing composition is small, the manufacturing cost required for polishing the silicon wafer can be suppressed.

When the finishing polishing composition and the pre-polishing composition of the present embodiment are used, part or all of the abrasive grains, water-soluble polymers, basic compounds, additives, etc., which are consumed and lost by polishing, can be used. It is reused by adding a compositional modifier. As the composition adjusting agent, those obtained by mixing abrasive grains, water-soluble polymers, basic compounds, additives, and the like in an arbitrary mixing ratio can be used. By adjusting the finishing polishing composition and the pre-polishing composition to a composition suitable for reuse by adding a composition adjusting agent, it is possible to perform preferable polishing. The concentration of the abrasive grains, the water-soluble molecules, the basic compound, and other additives contained in the composition adjusting agent can be arbitrary, and is not particularly limited, and can be appropriately adjusted depending on the groove size and the polishing conditions.

Further, the present embodiment is an example of the present invention, and the present invention is not limited to the embodiment. Further, the present embodiment can be variously modified or improved, and such modified or improved forms are also included in the present invention. For example, the finishing polishing composition and the pre-polishing composition of the present embodiment may be a single-liquid type, or a two-liquid type in which a part of the finishing polishing composition or a part of the pre-polishing composition is mixed in an arbitrary ratio. Multi-liquid type. also, When the ruthenium wafer is polished, the raw material for the finishing polishing composition and the pre-polishing composition of the present embodiment can be directly used for polishing, or the stock solution can be diluted to, for example, 10 times or more with a dilution liquid such as water. The material and the pre-grinding composition dilution were ground.

Example

Hereinafter, the present invention will be more specifically described with reference to Tables 1 and 2 in the examples and comparative examples.

Mixing abrasive grains formed with colloidal cerium oxide having an average primary particle diameter of 12 nm, 25 nm or 35 nm with a basic compound and a water-soluble polymer and a surfactant and pure water to prepare a pretreatment composition and a standard polishing composition The pre-grinding compositions a, b, c, d, h and the finishing polishing compositions e, f, g, i. The content of the abrasive grains, the basic compound, the water-soluble polymer, and the surfactant in each composition is as shown in Table 1, and the residual portion is pure water.

The basic compound species used is ammonia (NH ₃ ) or potassium hydroxide (KOH). The water-soluble polymer type and weight average molecular weight used are shown in Table 1. Further, "HEC" described in Table 1 means hydroxyethylcellulose, and "PVP" means polyvinylpyrrolidone. Further, the surfactant used is a block copolymer (PEO-PPO) formed of ethylene oxide (EO) and propylene oxide (PO), or polyethylene oxide decyl ether (C-PEO). .

Secondly, the hydrophilicity parameter P1 and the finishing precision parameter P2 of the pre-grinding compositions a, b, c, d, h, and the grinding processability parameter F1 of the finishing polishing compositions e, f, g, i are obtained. . The results are shown in Table 2.

The following is a description of the standard test 1 for obtaining the hydrophilicity parameter P1, the standard test 2 for obtaining the finishing precision P2, and the standard test 3 for the grinding processability parameter F1. Further, in the standard tests 1, 2, and 3, the test piece material for each parameter was obtained, and the polishing composition a, b, c, d, h and the finishing polishing composition e, f, g, i The material of the polished object to be polished is the same material.

Further, in the standard tests 1, 2, and 3, the test piece and the material for which each parameter is obtained are not the same as the wafer of the object to be polished, and the twin crystal of the same material as the wafer of the object to be polished is used. Round, but of course, a test piece identical to the wafer on which the object is polished can be used.

The hydrophilicity parameter P1 is obtained by sequentially performing the standard test 1 of the following X1 step to X6 steps.

[Standard Test 1]

(X1) pre-processing with respect to a wafer of the same material as the wafer of the object to be polished (in this embodiment, a wafer having a diameter of 300 mm, a conductive p-type, a crystal orientation of <100>, and no crystal defects) . In other words, after polishing with a composition for pretreatment using a composition for pretreatment, the composition is polished using a standard polishing composition, and then washed and dried.

The washing was carried out using a washing liquid obtained by mixing a concentration of 29:3 mass% of ammonia water, a concentration of 31% by mass of hydrogen peroxide water, and deionized water (DIW) in a volume ratio of 1:3:30. More specifically, two cleaning tanks having ultrasonic waves having a frequency of 950 kHz were prepared, and the cleaning liquid was stored in the first and second cleaning tanks and kept at 60 °C. Next, the polished germanium wafer is immersed in the first cleaning tank in a state where the ultrasonic oscillator is activated for 6 minutes, and then immersed in a cleaning tank for accommodating the ultrapure water in a state where the ultrasonic oscillator is activated. The cleaning was carried out, and then immersed in the second cleaning tank in the state where the ultrasonic oscillator was started for 6 minutes. Hereinafter, this type of washing step is referred to as SC-1 washing.

When the pre-treatment composition was used for the polishing, the polishing machine PNX-332B manufactured by Okamoto Machine Tool Co., Ltd. and the polishing table FP55 manufactured by Fujie Pang Co., Ltd. were used, and the polishing conditions were: polishing load 20 kPa, plate rotation speed 20 rpm, carrier Rotation speed 20 rpm, polishing time 2 min, supply rate of pretreatment composition 1 L/min, temperature of pretreatment composition 20 ° C, temperature of chassis cooling water 20 ° C

In addition, when grinding with a standard polishing composition, the grinding machine PNX-332B manufactured by Okamoto Machine Tool Co., Ltd. is used. Grinding table POLYPAS27NX manufactured by Fujitsupeng Co., Ltd., grinding conditions: grinding load 15 kPa, chassis rotation speed 30 rpm, carrier rotation speed 30 rpm, grinding time 2 min, standard polishing composition supply speed 2 L / min, standard polishing composition The temperature is 20 ° C, and the temperature of the chassis cooling water is 20 ° C.

The pretreatment composition contained 0.95 mass% of colloidal ceria having an average primary particle diameter of 35 nm and 0.065 mass% of potassium hydroxide, and the residue was pure water.

The standard polishing composition is composed of 0.46 mass% of colloidal ceria having an average primary particle diameter of 35 nm, 0.009% by mass of ammonia, 0.017 mass% of hydroxyethylcellulose having a weight average molecular weight of 250,000, and 0.002% by mass. A copolymer formed of polyethylene oxide and polypropylene oxide, and the residue is pure water.

(X2) A silicon wafer having a side length of 60 mm was produced by cutting the wafer after the pre-treatment. The enamel sheet test piece was immersed in a hydrogen fluoride aqueous solution having a concentration of 3 mass%, and then washed with pure water.

(X3) A ruthenium sheet test piece which was washed with pure water in the step X2 was polished by using the composition for polishing before use. The enamel sheet test piece was ground using a table grinder EJ-380IN manufactured by Nippon Co., Ltd., and a polishing table POLYPAS27 NX manufactured by Fujitsupeng Co., Ltd., and the grinding conditions were as follows: a grinding load of 16 kPa, a flat plate turning speed of 30 rpm, The carrier rotation speed was 30 rpm, the polishing time was 2 min, the supply rate of the pre-polishing composition was 30 mL/min, and the temperature of the pre-polishing composition was 20 °C.

(X4) Washing the flakes after grinding in the X3 step with pure water The surface of the test piece was used to clean the composition before polishing.

(X5) After the diagonal test piece of one of the enamel sheet test pieces was placed in a vertical direction, the test piece of the ruthenium sheet washed by the X4 step pure water was allowed to stand for 30 seconds, and then the test piece of the ruthenium slice in the diagonal line was measured. The length of the field where the surface is not wetted by pure water, and the length is used as the drainage distance.

(X6) From the measured drainage distance, the hydrophilicity parameter P1 of the pre-polishing composition was calculated by the following formula.

Hydrophilic parameter P1={(diagonal length [mm] of the sheet test piece) - (drainage distance [mm])} / (diagonal length of the sheet [mm]) × 100

The finishing precision parameter P2 is obtained by sequentially performing the standard test 2 of the following Y1 step to Y5 step.

[Standard Test 2]

(Y1) A wafer test piece of the same material as the wafer of the object to be polished (in this embodiment, a wafer having a diameter of 300 mm, a conductive type P, a crystal orientation of <100>, and no crystal defects) The treatment was carried out in the same manner as the X1 procedure of Standard Test 1. In other words, the ruthenium wafer test piece was polished using the composition for pretreatment, and then polished using a standard polishing composition, and then SC-1 was washed and dried to carry out pretreatment.

(Y2) The ruthenium wafer test piece subjected to the pretreatment in the Y1 step was re-polished using the pretreatment composition. This grinding system uses a grinder PNX-332B manufactured by Okamoto Machine Works Co., Ltd. Grinding table FP55 manufactured by the company has a grinding condition of 20 kPa, a flat rotation speed of 20 rpm, a carrier rotation speed of 20 rpm, a grinding time of 2 min, a supply speed of the pretreatment composition of 1 L/min, and a temperature of the pretreatment composition of 20 °C, the temperature of the plate cooling water is 20 °C.

(Y3) The ruthenium wafer test piece after the polishing in the Y2 step was polished by using the composition for polishing before use. In the case of grinding the enamel wafer test piece, a grinding machine PNX-332B manufactured by Okamoto Machine Tool Co., Ltd., and a polishing table POLYPAS27NX manufactured by Fujitsupeng Co., Ltd. were used. Further, the polishing conditions for polishing the silicon wafer test piece were: a polishing load of 15 kPa, a chassis rotation speed of 30 rpm, a carrier rotation speed of 30 rpm, a polishing time of 2 minutes, a supply rate of the front polishing composition of 2 L/min, and a pre-polishing composition. The temperature was 20 ° C, and the temperature of the chassis cooling water was 20 ° C.

(Y4) The polished silicon wafer test piece subjected to the Y2 step was polished using a standard polishing composition. In the case of grinding the enamel wafer test piece, a grinding machine PNX-332B manufactured by Okamoto Machine Tool Co., Ltd., and a polishing table POLYPAS27NX manufactured by Fujitsupeng Co., Ltd. were used. Further, the polishing conditions for polishing the tantalum wafer test piece were: a polishing load of 15 kPa, a flat plate rotation speed of 30 rpm, a carrier rotation speed of 30 rpm, a polishing time of 2 min, a supply rate of a standard polishing composition of 2 L/min, and a standard polishing composition. The temperature was 20 ° C, and the temperature of the plate cooling water was 20 ° C.

(Y5) The surface foreign matter inspection device SURFSCAN SP2 manufactured by KLA Co., Ltd. is used after the SC-1 cleaning and drying of the silicon wafer test piece after the Y3 step polishing and the Y4 step polishing. , measuring the surface of each wafer test piece by DWO method Turbidity. The turbidity h2 of the surface of the test piece of the silicon wafer after the Y3 step is polished, and the turbidity α of the surface of the test piece of the silicon wafer after the Y4 step is ground, and the precision of the finishing of the front polishing composition is calculated based on the following formula. Degree parameter P2.

Finishing precision parameter P2=h2/α×100

The polishing process parameter F1 is obtained by sequentially performing the following standard test 3 of the Z1 step to the Z6 step.

[Standard Test 3]

(Z1) A wafer test piece of the same material as the wafer of the object to be polished (in this embodiment, a wafer having a diameter of 200 mm, a conductive type P, a crystal orientation of <100>, and no crystal defects) Pre-implementation treatment, that is, polishing with a composition for pre-treatment with respect to a silicon wafer test piece, polishing with a standard polishing composition, followed by SC-1 washing and drying.

When the pre-treatment composition was used for the polishing, the grinding machine PNX-322 manufactured by Okamoto Machine Tool Co., Ltd. and the polishing table FP55 manufactured by Fujie Pang Co., Ltd. were used, and the polishing conditions were as follows: grinding load 15 kPa, plate rotation speed 30 rpm, carrier The rotation speed was 30 rpm, the polishing time was 3 min, the supply rate of the pretreatment composition was 0.55 L/min, the temperature of the pretreatment composition was 20 ° C, and the temperature of the flat cooling water was 20 ° C.

In addition, the polishing machine PNX-322 manufactured by Okamoto Machine Manufacturing Co., Ltd. and the polishing table POLYPAS27NX manufactured by Fujitsupeng Co., Ltd. were used for the polishing using the standard polishing composition. The polishing load is 15 kPa, the plate rotation speed is 30 rpm, the carrier rotation speed is 30 rpm, the polishing time is 4 min, the supply rate of the standard polishing composition is 0.4 L/min, the temperature of the standard polishing composition is 20 ° C, and the temperature of the flat cooling water is 20 ° C. .

(Z2) The mass of the silicon wafer test piece after the treatment before the Z1 step was measured. Next, the silicon wafer test piece was immersed in a hydrogen fluoride aqueous solution having a concentration of 3 mass%, and then washed with pure water.

(Z3) A silicon wafer test piece which was washed with pure water of the Z2 step was polished using a finishing polishing composition. When grinding the test piece of the tantalum wafer, the grinding machine PNX-322 manufactured by Okamoto Machine Tool Co., Ltd. and the polishing table POLYPAS27NX manufactured by Fujie Co., Ltd. were used. Further, the polishing conditions for polishing the tantalum wafer test piece were: a polishing load of 15 kPa, a chassis rotation speed of 30 rpm, a carrier rotation speed of 30 rpm, a polishing time of 15 minutes, a supply speed of a finishing polishing composition of 0.4 L/min, and a finishing polishing. The temperature of the composition was 20 ° C, and the temperature of the chassis cooling water was 20 ° C.

(Z4) A silicon wafer test piece which was washed with pure water of the Z2 step was polished using a standard polishing composition. When grinding the test piece of the tantalum wafer, the grinder PNX-322 manufactured by Okamoto Machine Tool Co., Ltd. and the polishing table POLYPAS27NX manufactured by Fujitsupeng Co., Ltd. were used. Further, the polishing conditions for polishing the tantalum wafer test piece were a polishing load of 15 kPa, a flat plate rotation speed of 30 rpm, a carrier rotation speed of 30 rpm, a polishing time of 15 minutes, a supply rate of a standard polishing composition of 0.4 L/min, and a standard polishing composition. The temperature is 20 ° C, and the temperature of the flat cooling water is 20 ° C.

(Z5) Relative to the wafer test after grinding in the Z3 step The test piece and the ruthenium wafer test piece polished by the Z4 step were each subjected to SC-1 washing and drying, and then the mass was measured.

(Z6) The difference between the mass of the wafer test piece measured by the Z2 step and the mass of the wafer test piece measured by the Z5 step, and the grinding of the grinding speed of the Z3 step and the grinding of the Z4 step are respectively calculated. Speed β. Next, the polishing processability parameter F1 of the finishing polishing composition is calculated based on the following formula.

Grinding processability parameter F1=R/β×100

The polishing compositions of Examples 1 to 4 and Comparative Examples 1 to 4 were produced by appropriately combining the pre-grinding compositions a, b, c, d, and h and the finishing polishing compositions e, f, g, and i. Set (refer to Table 2). Next, the wafer of the object to be polished is polished using the polishing composition set, and the turbidity of the surface of the wafer is measured after polishing. The polishing method of the ruthenium wafer includes a first polishing step of polishing the composition before use, a polishing step before the polishing using the polishing composition before use (second polishing step), and a finishing polishing process. A method of finishing a grinding step with a composition.

The method of polishing the ruthenium wafer and the method of measuring the turbidity will be specifically described below.

(1) First, the wafer was subjected to the same treatment as the X1 step of the standard test 1 with respect to the wafer having a diameter of 300 mm, a conductive type P, a crystal orientation of <100>, and no crystal defects. In other words, after polishing with a composition for pretreatment using a composition for pretreatment, the composition is polished using a standard polishing composition, and then SC-1 is washed and dried to carry out pretreatment.

(2) The second use of the pre-treatment composition is re-ground (1) The processed germanium wafer before the step. The polishing apparatus and polishing table used in polishing the wafer were the same as the Y2 procedure of Standard Test 2. Further, the polishing conditions for polishing the tantalum wafer were the same as the Y2 procedure of Standard Test 2.

(3) Next, the polishing composition is used before the polishing composition is set, and the ruthenium wafer after the polishing is re-polished using the pre-treatment composition in the step of polishing (2). The polishing apparatus and polishing table used in polishing the wafer were the same as the Y3 procedure of Standard Test 2. Further, the polishing conditions for polishing the tantalum wafer were the same as the Y3 procedure of Standard Test 2.

(4) Further, the finishing polishing composition is used in the polishing composition set, and the ruthenium wafer after the polishing composition is polished in the step (3). The polishing apparatus and polishing table used in polishing the wafer were the same as the Y3 procedure of Standard Test 2. Further, the polishing conditions for polishing the tantalum wafer were the same as the Y3 procedure of Standard Test 2.

(5) Next, SC-1 is washed and dried with respect to the tantalum wafer polished by the finishing polishing composition in the step (4), and then the surface foreign matter inspection device SURFSCAN SP2 manufactured by KLA Co., Ltd. is used in the DWO manner. The turbidity of the surface of the tantalum wafer was measured

The measurement results of turbidity are shown in Table 2. In the tantalum wafer after polishing using the polishing composition set of Examples 1 to 4, the hydrophilicity parameter P1 of the pre-polishing composition was less than 100, and the finishing precision parameter P2 of the pre-polishing composition was 1000. In the following, since the polishing processability parameter F1 of the composition for finishing polishing is 80 or less, the turbidity of the surface of the wafer after finishing polishing can be reduced, and a high-quality surface to be polished can be obtained.

The hydrophilicity parameter P1 of the pre-polishing composition, the finishing precision parameter P2 of the pre-polishing composition, and finishing were relatively used in the polishing wafer after the polishing composition set of Comparative Examples 1 to 4 were used. None of the polishing process parameters F1 of the polishing composition can meet the necessary requirements, so that the surface of the wafer after finishing polishing has a high turbidity.

Claims (8)

A polishing composition kit, which is a finishing polishing composition for use in a finishing polishing step for finishing polishing a silicon wafer, and a polishing step used in a stage before the finishing polishing step The polishing composition set of the polishing composition before the pre-grinding step, the hydrophilicity parameter P1 of the pre-polishing composition obtained in the standard test 1 is less than 100, and the pre-grinding for the standard test 2 The finishing precision parameter P2 of the composition is 1000 or less, and the grinding processability parameter F1 of the finishing polishing composition obtained in the standard test 3 is 80 or less. The polishing composition kit according to claim 1, wherein the finishing polishing composition and the pre-polishing composition both contain abrasive grains, a basic compound, and a water-soluble polymer. A pre-polishing composition which is a composition for polishing before a pre-polishing step of a polishing step of a stage prior to a finishing polishing step of finishing a tantalum wafer, and a hydrophilic parameter obtained in Standard Test 1 P1 is less than 100, and the precision precision parameter P2 obtained by the standard test 2 is 1000 or less. A composition for polishing prior to claim 3, which comprises abrasive grains and a basic compound and a water-soluble polymer. A method for polishing a tantalum wafer, which comprises a finishing polishing step for finishing polishing a tantalum wafer, and a polishing method for a wafer after a pre-grinding step of a grinding step before the finishing polishing step, Performing the aforementioned finishing using the polishing composition kit of claim 1 or 2 The grinding step and the aforementioned pre-grinding step. A method for polishing a tantalum wafer, which comprises a finishing polishing step for finishing polishing a tantalum wafer, and a polishing method for a wafer after a pre-grinding step of a grinding step before the finishing polishing step, The foregoing pre-grinding step is carried out using the composition for grinding prior to claim 3 or 4. A finishing polishing composition for polishing a wafer prepared by a finishing polishing step for finishing polishing a silicon wafer, and a pre-polishing step of a polishing step before the finishing polishing step In the method, the finishing polishing composition for the finishing polishing step, the grinding processability parameter F1 obtained in the standard test 3 is 80 or less. The finishing polishing composition according to claim 7, which comprises abrasive grains and a basic compound and a water-soluble polymer.