TW201724236A - Polishing method, composition for removing impurity, substrate, and method for manufacturing same - Google Patents

Abstract

Provided is a polishing method with which it is possible to sufficiently remove impurities present on an object to be polished. An object to be polished that has an organic film on the surface thereof is polished using a polishing composition that contains abrasive grains, and is subsequently polished using an impurity-removing composition that contains an organic compound to eliminate impurities present on the object to be polished. The organic compound contains a surfactant and/or a water-soluble polymer. The surfactant contains a hydrophilic group and a hydrophobic group that includes a C3 or higher hydrocarbon group, and the main chain of the water-soluble polymer is hydrophobic.

Description

Polishing method and composition for removing impurities, substrate and method for producing same

The present invention relates to a polishing method for polishing an object having an organic film on a polishing surface, and a composition for removing impurities used in the polishing method. Further, the present invention relates to a substrate produced by the above polishing method and a method of manufacturing the same.

In recent years, with the multilayer wiring on the surface of a semiconductor substrate, a so-called chemical mechanical polishing (CMP) technique in which a semiconductor substrate is physically polished and planarized is used in manufacturing a device. CMP is a technique for flattening the surface of a polishing target such as a semiconductor substrate by using a polishing composition (slurry) containing abrasive grains, an anticorrosive agent, a surfactant, or the like, and is used for polishing by ruthenium, polycrystalline germanium, A wiring made of a tantalum oxide film, a tantalum nitride, a metal, or the like, a plug, or the like, or an organic film on the surface of the semiconductor substrate.

A large amount of impurities (defects) remain on the surface of the semiconductor substrate after the CMP step. In terms of impurities, it contains abrasive particles, metals, and organic substances from the polishing composition used in CMP (for example, anti-corrosion) Agent or surfactant), or a ruthenium-containing material and a metal produced by polishing a ruthenium-containing material, an organic film, a metal wiring, a plug, or the like as an object to be polished, and further comprising a pad formed by polishing the polishing pad. Organic matter such as chips.

If the surface of the semiconductor substrate is contaminated by such impurities, the impurities may adversely affect the electrical characteristics of the semiconductor, and thus the reliability of the device may be lowered. Furthermore, when the pollution caused by the organic matter is significant, there is a possibility that the device is damaged. Therefore, it is necessary to perform cleaning of the semiconductor substrate after the CMP step, and to remove such impurities from the surface of the semiconductor substrate.

In the cleaning of the semiconductor substrate, a detergent is used. For example, in the technique disclosed in Patent Document 1, the semiconductor substrate is immersed in the detergent to remove impurities from the surface of the semiconductor substrate.

However, in the technique disclosed in Patent Document 1, the impurities cannot be sufficiently removed from the surface of the semiconductor substrate, and there is a possibility that a large amount of impurities remain on the surface of the object to be polished such as a semiconductor substrate.

[Previous Technical Literature] [Patent Document]

[Patent Document 1] International Publication No. 2005/040324

[Patent Document 2] Japanese Patent Laid-Open Publication No. 268409

[Patent Document 3] Japanese Patent Laid-Open Publication No. 335896

Therefore, the present invention has been made in order to solve the problems of the above-described conventional techniques, and to provide a polishing method capable of sufficiently removing impurities present on the object to be polished. In addition, it is a problem to provide a composition for removing impurities which can sufficiently remove impurities present on the object to be polished. Further, another object is to provide a substrate which sufficiently removes impurities from the surface and a method for producing the same.

In order to solve the above problems, the polishing method according to one aspect of the present invention includes a polishing step of polishing an object to be polished having an organic film on a surface using a polishing composition containing abrasive grains, and polishing using a composition for removing impurities containing an organic compound. An impurity removal step of removing the impurities present on the object to be polished in the polishing step; the organic compound has at least one of a surfactant and a water-soluble polymer, and the surfactant has a hydrophilic group And a hydrophobic group having a hydrocarbon group having 3 or more carbon atoms, and the water-soluble polymer has a main chain which is hydrophobic.

Moreover, the method of manufacturing a substrate according to another aspect of the present invention is directed to a step of polishing a substrate having an organic film on its surface by the polishing method according to the above aspect.

Furthermore, the substrate according to another aspect of the present invention is manufactured by the method for producing a substrate according to the above another aspect.

Furthermore, the impurity-removing composition according to another aspect of the present invention is an impurity-removing composition used for removing impurities present on an object to be polished having an organic film on the surface thereof, and contains an organic compound, and the organic compound has At least one of the surfactant and the water-soluble polymer has a hydrophilic group and a hydrophobic group having a hydrocarbon group having 3 or more carbon atoms, and the water-soluble polymer has a hydrophobic main chain.

According to the present invention, impurities existing on the object to be polished can be sufficiently removed.

Hereinafter, an embodiment of the present invention will be described in detail. Further, the present embodiment is an example of the present invention, and the present invention is not limited to the embodiment. Further, various modifications and improvements may be added to the embodiment, and such modifications or improvements may be included in the invention.

The polishing method of the present embodiment is a method of polishing an object to be polished having an organic film on a polishing surface, and a polishing step of polishing an object having an organic film on a surface by using a polishing composition containing abrasive grains; and using an organic compound The impurity removing composition polishes the object to be polished which is polished in the polishing step to remove the impurity removing step of the impurities present on the object to be polished.

An organic compound contained in the composition for impurity removal, There is at least one of a surfactant and a water-soluble polymer. Further, the surfactant has a hydrophilic group and a hydrophobic group having a hydrocarbon group having 3 or more carbon atoms. Further, the water-soluble polymer has a hydrophobic main chain.

When the object to be polished having the organic film on the surface is polished by such a polishing method, the object to be polished can be sufficiently removed while polishing the object to be polished. In other words, although various impurities are present on the object to be polished after the polishing step, impurities which are present on the object to be polished can be sufficiently removed in the impurity removing step, so that polishing which sufficiently removes impurities can be obtained. Object.

Hereinafter, the polishing method and the composition for removing impurities of the present embodiment will be described in more detail.

1.About the object to be polished

The object to be polished to which the polishing method of the present embodiment is applied is one in which an organic film is formed on the surface of the substrate. The material of the substrate is not particularly limited, and examples thereof include elemental ruthenium, ruthenium compound, metal, ceramic, and resin.

Examples of the elemental oxime include a single crystal ruthenium, a polycrystalline ruthenium (polycrystalline ruthenium), an amorphous ruthenium, and the like. Further, examples of the antimony compound include cerium nitride, cerium oxide (for example, a cerium oxide interlayer insulating film formed using tetraethoxy decane (TEOS)), and cerium carbide.

Further, examples of the metal include tungsten, copper, aluminum, ruthenium, cobalt, nickel, titanium, rhodium, gold, silver, platinum, palladium, rhodium, ruthenium, osmium, iridium, and the like. These metals can be contained in the form of alloys or metal compounds.

On the other hand, the type of the organic film is not particularly limited, and For example, a color filter for a liquid crystal display device, a photoresist, an antireflection film, and a fluorine-containing insulating film are used.

Specific examples of the object to be polished having an organic film on the surface include a substrate having an organic film on its surface. The substrate having an organic film on the surface of the polishing target of the polishing method of the present embodiment includes, for example, a substrate having a positive or negative photoresist formed on the wafer, and a color filter for a liquid crystal display device. A substrate for an organic film such as a transparent resin for a liquid crystal display device or a black matrix for a liquid crystal panel, or a CFx (fluorocarbon) film having a CHF-based organic source as a source gas and formed by plasma CVD or the like. The substrate of the film.

2. About the grinding step and the polishing composition

The polishing step in the polishing method of the present embodiment is a step of polishing an object to be polished having an organic film on the surface thereof using a polishing composition containing abrasive grains. By this step, chemical mechanical polishing of the organic film or substrate of the object to be polished is performed. The polishing conditions are not particularly limited, and a polishing composition containing abrasive grains may be present between an object to be polished (for example, a substrate) having an organic film on the surface thereof and a polishing pad, and for example, a polishing apparatus (single-side polishing apparatus, two sides) may be used. The polishing apparatus or the like is polished under general polishing conditions to polish the object to be polished having an organic film on the surface.

The type of the polishing pad is not particularly limited, and may be a foam, or may be a non-foamed fabric such as a cloth or a non-woven fabric, and a general nonwoven fabric, a foamed polyurethane, a porous fluororesin or the like may be used. Further, the polishing pad may be subjected to groove processing for forming a groove in which the polishing composition is accumulated. As research Grinding pad material, can use polyurethane, acrylic, polyester, acrylic-ester copolymer, polytetrafluoroethylene, polypropylene, polyethylene, poly 4-methylpentene, cellulose , cellulose ester, polyamide (nylon, aramid, etc.), polyimine, polyamidamine, polyoxyalkylene copolymer, oxirane compound, phenolic resin, polystyrene, polycarbonate A resin such as an ester or an epoxy resin.

When the polishing composition contains abrasive grains, the composition thereof is not particularly limited, and various additives may be contained in addition to the abrasive grains. Further, it is also possible to adjust a slurry obtained by dispersing abrasive grains in a liquid medium. The polishing composition will be described in detail below.

2-1 About abrasive grains

The abrasive grains contained in the polishing composition may be any of inorganic particles, organic particles, and organic-inorganic composite particles. Specific examples of the inorganic particles include particles composed of a metal oxide such as cerium oxide, aluminum oxide, cerium oxide, or titanium oxide, and cerium nitride particles, cerium carbide particles, and boron nitride particles. Specific examples of the organic particles include polymethyl methacrylate (PMMA) particles. Among these, cerium oxide particles are preferred, and colloidal cerium oxide is particularly preferred. These abrasive grains may be used alone or in combination of two or more.

The abrasive particles can also be surface modified. In general colloidal cerium oxide, since the value of the cerium potential is close to zero under acidic conditions, cerium oxide particles do not mutually electrically repel each other under acidic conditions and are liable to cause aggregation. In contrast, the surface modification is an abrasive particle having a large positive or negative value at a potential other under acidic conditions, and is also mutually acidic under acidic conditions. When the repulsion occurs strongly and the dispersion is well achieved, the storage stability of the polishing composition can be improved. Such surface-modified abrasive grains can be obtained, for example, by mixing a metal such as aluminum, titanium, zirconium or the like or an oxide thereof with abrasive grains to be doped on the surface of the abrasive grains.

Alternatively, the surface-modified abrasive grains in the polishing composition may be cerium oxide having an organic acid immobilized on the surface. Among them, colloidal cerium oxide to which an organic acid is immobilized can be preferably used. The immobilization of the colloidal cerium oxide by the organic acid is carried out by chemically bonding the functional group of the organic acid to the surface of the colloidal cerium oxide. Only the colloidal cerium oxide and the organic acid coexist, and the immobilization of the colloidal cerium oxide by the organic acid cannot be achieved.

To immobilize a sulfonic acid which is a kind of organic acid to colloidal cerium oxide, for example, according to the method described in "Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups", Chem. Commun. 246-247 (2003). Come on. Specifically, the sulfonic acid group can be oxidized to a surface by coupling a decane coupling agent having a thiol group such as 3-mercaptopropyltrimethoxydecane with a colloidal cerium oxide and then oxidizing the thiol group with hydrogen peroxide. Colloidal cerium oxide.

Alternatively, if the carboxylic acid is to be immobilized on colloidal cerium oxide, for example, according to "Novel Silane Coupling Agents Containing a Photolabile 2-Nitrobenzyl Ester for Introduction of a Carboxy Group on the Surface of Silica Gel", Chemistry Letters, 3, 228-229 (2000) The method described is carried out. Specifically, the carboxylic acid can be immobilized on the surface by coupling a decane coupling agent containing a photoreactive 2-nitrobenzyl ester with a colloidal cerium oxide. Colloidal cerium oxide.

The content of the abrasive grains in the polishing composition may be 0.1% by mass or more, preferably 0.5% by mass or more. As the content of the abrasive grains increases, there is an advantage that the polishing composition has an improved removal rate (polishing speed) of the object to be polished.

The content of the abrasive grains in the polishing composition may be 20% by mass or less, preferably 15% by mass or less, and more preferably 10% by mass or less. As the content of the abrasive grains is reduced, the material cost of the polishing composition can be reduced, and the aggregation of the abrasive grains is less likely to occur. Moreover, by polishing the object to be polished by using the polishing composition, it is easy to obtain a surface to be polished having few surface defects.

The average primary particle diameter of the abrasive grains may be 5 nm or more, preferably 7 nm or more, and more preferably 10 nm or more. As the average primary particle diameter of the abrasive grains increases, the polishing rate of the polishing target to the object to be polished can be increased. Further, the value of the average primary particle diameter of the abrasive grains can be calculated, for example, based on the specific surface area of the abrasive grains measured by the BET method.

Further, the abrasive grains may have an average primary particle diameter of 100 nm or less, preferably 90 nm or less, more preferably 80 nm or less. As the average primary particle diameter of the abrasive grains is reduced, it is easy to obtain a surface to be polished having a small surface defect by polishing the object to be polished by using the polishing composition.

The average secondary particle diameter of the abrasive grains may be 300 nm or less, preferably 250 nm or less, more preferably 200 nm or less. The value of the average secondary particle diameter of the abrasive particles can be measured, for example, by a laser light scattering method.

Dividing the value of the average secondary particle diameter of the abrasive particles by the value of the average primary particle diameter The obtained abrasive grains may have an average degree of association of 1.2 or more, preferably 1.5 or more. As the average degree of association of the abrasive grains increases, the polishing rate of the object to be polished by the polishing composition can be increased.

The average degree of association of the abrasive grains may be 5 or less, preferably 4 or less, more preferably 3 or less. As the average degree of association of the abrasive grains is reduced, it is easy to obtain a surface to be polished having less surface defects by polishing the object to be polished by using the polishing composition.

2-2 About pH

The pH of the polishing composition can be set to less than 10, preferably 5 or less. When the pH is 5 or less, the workability of the polishing composition can be improved, and if it is 3 or less, it is more preferable, and if it is 2.5 or less, it is particularly preferable. When the pH exceeds 5, the operability tends to decrease. The lower limit of the pH of the polishing composition is not particularly limited. However, the higher the pH, the higher the dispersibility of the abrasive grains in the polishing composition, and therefore it is preferably 1 or more.

2-3 About additives

In the polishing composition, various additives such as a pH adjuster, an oxidizing agent, a crosslinking agent, an anticorrosive agent, a surfactant, a water-soluble polymer, a preservative, and an antifungal agent may be added as needed to improve the performance. Further, as the additive, a compound having three or more oxygen atoms O and having a standard potential of 0.50 V or more may be added.

[About pH adjuster]

The pH adjuster to be used as needed in order to adjust the pH of the polishing composition to a desired value may be any of an acid and a base, and may be any of an inorganic or an organic compound. As the pH adjuster, for example, nitric acid, phosphoric acid, hydrochloric acid, sulfuric acid, citric acid or the like can be used.

[About a compound having three or more oxygen atoms O and having a standard potential of 0.50 V or more]

Examples of the compound having three or more oxygen atoms O and a standard potential of 0.50 V or more include, for example, ammonium cerium nitrate ((NH ₄ ) ₂ [Ce(NO ₃ ) ₆ ])), and periodic acid (HIO ₄ ). , periodic periodic acid (H ₅ IO ₆ ), perchloric acid (HClO ₄ ), perbromic acid (HBrO ₄ ), potassium bromate (KBrO ₃ ), sulfuric acid (H ₂ SO ₄ ), potassium permanganate (KMnO ₄ ) , persulfate (H ₂ SO ₅ ), Oxone (registered trademark, potassium peroxymonosulfate), vanadium pentoxide (V ₂ O ₅ ), potassium dichromate (K ₂ Cr ₂ O ₇ ), manganese oxide ( III) (Mn ₂ O ₃ ), potassium perruthenate (KRuO ₄ ), ruthenium tetroxide (RuO ₄ ), nickel oxide (Ni ₂ O ₃ ), palladium hydroxide (Pd(OH) ₄ ), metastannic acid ( H ₂ SnO ₃ ), nitric acid (HNO ₃ ), ammonium peroxodisulphate ((NH ₄ ) ₂ S ₂ O ₈ ), selenic acid (H ₂ SeO ₄ ), peroxydisulfuric acid (H ₂ S ₂ O ₈ ) , aluminum nitrate (Al(NO ₃ ) ₃ ), ammonium persulfate ((NH ₄ ) ₂ SO ₅ ), ammonium perchlorate (NH ₄ ClO ₄ ), ammonium permanganate (NH ₄ MnO ₄ ), etc., but not Limited to this.

Further, Oxone is a double salt composed of potassium ion, hydrogen persulfate ion, sulfate ion, and hydrogen sulfate ion, and is a compound represented by the chemical formula 2KHSO ₅ ‧KHSO ₄ ‧K ₂ SO ₄ .

Although not bound by theory, a compound having three or more oxygen atoms O and a standard potential of 0.50 V or more has strong oxidizing properties and has There is a specific structure having three or more oxygen atoms O. It is considered that the terminal structure in the organic film can be converted from insoluble to water-soluble, and the affinity between the organic film and the abrasive grains can be improved, and the mechanical action can be enhanced.

This is different from the fact that only a compound having a higher standard potential (stronger oxidizing power) is selected as an oxidizing agent to convert the surface of the object to be a weaker oxide, and the oxide is mechanically removed by the abrasive particles, or The technique in which the wrong agent is dissolved to increase the polishing rate, and the additive has a certain standard potential or more and has the above specific structure, and it is considered that the above mechanism can be exhibited to increase the polishing rate.

When the number of oxygen atoms O is less than three, or the standard potential is less than 0.50 V, there is no strong oxidizing property, and the terminal structure in the organic film tends to be incapable of changing from insoluble to water-soluble. Therefore, the affinity between the organic film and the abrasive grains is weak, and it tends to be less likely to increase the mechanical action.

The content of the compound having three or more oxygen atoms O and having a standard potential of 0.50 V or more may be 0.005% by mass or more, preferably 0.01% by mass or more. As the content of a compound having three or more oxygen atoms O and a standard potential of 0.50 V or more is increased, the terminal structure in the organic film can be converted into water solubility, and the mechanical action is enhanced.

Further, the content of the compound having three or more oxygen atoms O and a standard potential of 0.50 V or more may be 5.0% by mass or less, preferably 3.0% by mass or less, and more preferably 1.0% by mass or less. If it is a range, the material cost of a polishing composition can be reduced.

In addition, the term "standard potential" means that for any electrochemical reaction, the activity of all chemical species involved in the reaction is 1 (standard) State), and exhibits an electrode potential in an equilibrium state. The standard potential energy can be measured by cyclic voltammetry or the like in the form of a potential difference from the reference electrode.

Further, a compound having three or more oxygen atoms O and having a standard potential of 0.50 V or more functions as a pH adjuster having a pH adjustment function.

[about oxidant]

The oxidizing agent has an action of oxidizing the surface of the object to be polished, and when an oxidizing agent is added to the polishing composition, there is an effect of improving the polishing rate by the polishing composition. The content of the oxidizing agent in the polishing composition may be 0.1% by mass or more, preferably 0.5% by mass or more, of the polishing composition. Further, the content of the oxidizing agent may be 4% by mass or less, preferably 3% by mass or less, of the polishing composition. When the content of the oxidizing agent is less than 0.1% by mass or more than 4% by mass, there is a tendency that the polishing rate of the organic film of a practical level is not easily obtained.

The oxidizing agent which can be used is, for example, a peroxide Specific examples of the peroxide include persulfates such as hydrogen peroxide, peracetic acid, percarbonate, urea peroxide, perchloric acid, sodium persulfate, potassium persulfate, and ammonium persulfate. Among these, persulfate and hydrogen peroxide are preferred from the viewpoint of polishing rate, and hydrogen peroxide is particularly preferable from the viewpoint of stability in an aqueous solution and environmental burden.

[about the wrong agent]

The compounding agent optionally contained in the polishing composition has a chemical etching tool The effect of the surface of the substrate having the organic film can enhance the polishing rate of the polishing composition.

The upper limit of the content of the complexing agent optionally contained in the polishing composition may be 10% by mass, preferably 1% by mass. As the content of the binder decreases, excessive etching of the surface of the substrate on which the organic film is formed is less likely to occur. As a result, excessive polishing can be suppressed.

The lower limit of the content of the compounding agent optionally contained in the polishing composition may be 0.01% by mass, preferably 0.1% by mass. As the content of the binder increases, the etching effect on the surface of the substrate on which the organic film is formed can be increased. As a result, it contributes to the improvement of the polishing rate of the polishing composition.

Miscible agents which can be used are, for example, inorganic acids, organic acids, and amino acids. Specific examples of the inorganic acid include sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid. Specific examples of the organic acid include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, and 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, succinic acid, Glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, lactic acid. Organic sulfuric acid such as methanesulfonic acid, ethanesulfonic acid or 2-hydroxyethanesulfonic acid can also be used. In place of an inorganic acid or an organic acid, or a combination with an inorganic acid or an organic acid, a salt of an inorganic acid or an alkali metal salt of an organic acid or the like may be used.

Specific examples of the amino acid include glycine, α-alanine, β-alanine, N-methylglycine, N,N-dimethylglycine, and 2-aminobutyl. Acid, n-proline, valine, leucine, white amine Acid, isoleucine, phenylalanine, valine, sarcosine, ornithine, lysine, taurine, serine, threonine, homoserine, tyrosine, cytosine , flavonoids, 3,5-diiodotyrosine, β-(3,4-dihydroxyphenyl)alanine, thyroxine, 4-hydroxyproline, cysteine, methionine, B Thiamine, lanthionine, cystathionine, cystine, sulfoalanine, aspartic acid, glutamic acid, S-(carboxymethyl)cysteine, 4-aminobutyric acid, Aspartame, branamine, azacidine, arginine, concanavalin, citrulline, δ-hydroxy lysine, creatine, histidine, 1-methylhistidine, Amino acid such as 3-methylhistamine and tryptophan. Among these, as the binder, from the viewpoint of improving the polishing property, glycine, alanine, malic acid, tartaric acid, citric acid, glycolic acid, 2-hydroxyethanesulfonic acid or the like are preferred.

[about anti-corrosion agent]

The content of the anticorrosive agent optionally contained in the polishing composition may be 0.1% by mass or more, preferably 0.2% by mass or more, of the polishing composition. Further, the content of the anticorrosive agent may be 0.4% by mass or less, preferably 0.3% by mass or less, based on the polishing composition. When the content of the anticorrosive agent is less than 0.2% by mass or more than 0.4% by mass, there is a tendency that it is difficult to obtain a practical level of anticorrosive effect.

Examples of the anticorrosive agent which can be used include a heterocyclic compound or a heteroaryl compound having at least a 5 to 6 membered ring, having two or more double bonds, and having one or more nitrogen atoms. For example, a compound having a pyridine ring, a pyrazole ring, a pyrimidine ring, an imidazole ring, a triazole ring, or a benzotriazole ring can be mentioned. Also, as an anticorrosive agent, benzotriazole can be used. (BTA). When an anticorrosive agent is added, there is an effect of improving the polishing rate of the polishing composition.

[About surfactant]

The content of the surfactant which is optionally contained in the polishing composition may be 0.01% by mass or more, preferably 0.02% by mass or more. Further, the content of the surfactant may be 2% by mass or less, preferably 1% by mass or less, based on the polishing composition. The surfactant may include one or more selected from the group consisting of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant.

Examples of the anionic surfactant include polyoxyethylene alkyl ether acetic acid, polyoxyethylene alkyl sulfate, alkyl sulfate, polyoxyethylene alkyl ether sulfuric acid, alkyl ether sulfuric acid, and alkylbenzenesulfonate. Acid, alkyl phosphate, polyoxyethylene alkyl phosphate, polyoxyethylene sulfosuccinic acid, alkyl sulfosuccinic acid, alkyl naphthalenesulfonic acid, alkyl diphenyl ether disulfonic acid, and the like Salt and so on.

Examples of the cationic surfactant include an alkyltrimethylammonium salt, an alkyldimethylammonium salt, an alkylbenzyldimethylammonium salt, and an alkylamine salt.

Examples of the amphoteric surfactant include an alkylbetaine, an alkylamine oxide, and the like.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, sorbitan fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester, and polyoxygen. Vinyl alkylamine, and alkyl alkanol Amidoxime and the like.

Preferred surfactants among these are polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl ether sulfates, alkyl ether sulfates, alkylbenzene sulfonates, and polyoxyethylene alkyl ethers.

These surfactants can form a stronger film on the surface of the object to be polished because of the high chemical or physical adsorption force on the surface of the object to be polished. In this way, it is advantageous to improve the flatness of the surface of the object to be polished after polishing using the polishing composition.

[About water soluble polymer]

The polishing composition may contain a water-soluble polymer. Further, there are cases where a water-soluble polymer is referred to as a surfactant. The content of the water-soluble polymer may be 0.01% by mass or more, preferably 0.02% by mass or more, based on the polishing composition. Further, the content of the water-soluble polymer may be 2% by mass or less, preferably 1% by mass or less, based on the polishing composition. Examples of the water-soluble polymer that can be used include sodium polyacrylate, polypropylene decylamine, polyvinyl alcohol, polyethyleneimine, polyethylene oxide, and polyvinylpyrrolidone.

[About preservatives and fungicides]

The polishing composition may contain a preservative and an antifungal agent. Examples of the preservative and the antifungal agent include isothiazoline such as 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one. Preservatives, parabens, or phenoxyethanol. These preservatives and antifungal agents may be used alone or in combination of two or more.

2-4 About liquid media

The polishing composition may contain a liquid medium such as water or an organic solvent. The liquid medium functions as a dispersion medium or a solvent for dispersing or dissolving the components (abrasive grains, additives, and the like) of the polishing composition. The liquid medium may be water or an organic solvent, and one type may be used alone or two or more types may be used in combination, and water is preferably used. However, it is preferable to use water which does not contain impurities as much as possible, from the viewpoint of suppressing the action of the respective components. Specifically, it is preferably pure water or ultrapure water or distilled water which is removed by an ion exchange resin and then passed through a filter to remove foreign matter.

Further, the polishing composition may be of a one-liquid type or a multi-liquid type including a two-liquid type. Further, the polishing composition can be prepared by diluting a stock solution of the polishing composition with a liquid medium such as water.

3. About impurity removal step and impurity removal composition

The impurity removal step in the polishing method of the present embodiment is a step of polishing the object to be polished which is polished in the polishing step by using the impurity-removing composition containing the organic compound to remove the impurities present on the object to be polished. The impurity removing composition used in the impurity removing step does not contain abrasive grains or has a small amount even when it is contained. Therefore, chemical mechanical polishing is not substantially performed in the impurity removing step, and the impurity removal treatment is performed.

Impurities (defects) are sometimes present in a large amount on the object to be polished after the polishing step. In terms of impurities, it is included in the grinding step. When the polishing target is a substrate having an organic film on its surface, the polishing target is used to form a ruthenium-containing material by polishing a metal wiring or a plug. Metal) and organic film, or chippings generated by polishing pads used for polishing. By polishing the object to be polished which is present on the surface by using the impurity removing composition, an object to be polished which sufficiently removes impurities can be obtained.

In addition, the impurity-removing composition of the present embodiment can be used for the object to be polished which has been polished using the polishing composition containing the abrasive grains. However, the object to be polished is not limited to the object to be polished immediately after polishing, and the object to be polished before polishing may be used. It can also be used for the object to be polished which has been washed after polishing. In other words, it is possible to sufficiently remove the impurities present on the surface of the object to be polished by the use of the impurity-removing composition of the present embodiment to remove impurities.

The impurity removal step is for the purpose of removing impurities from the object to be polished, and since polishing is not required, the polishing rate of the organic film in the impurity removal step may be 0.5 nm/min or less, preferably 0.3 nm/min or less, more preferably It is 0.1 nm/min or less, and more preferably 0.05 nm/min or less. That is, the polishing rate of the organic film in the impurity removing step is substantially zero.

The condition for removing the impurities is not particularly limited, and the composition for removing impurities may be present between the object to be polished (for example, a substrate) having an organic film on the surface thereof and the polishing pad, and for example, a polishing apparatus (single-surface polishing apparatus, A double-sided polishing apparatus or the like) is polished under general polishing conditions to carry out impurities present on an object to be polished having an organic film on its surface. Removal.

The type of the polishing pad used in the impurity removing step is not particularly limited, and the aforementioned polishing pad in the two items can be used. However, it is preferable to use a soft polishing pad (cushion). Specifically, the pad hardness is preferably 60 or less, more preferably 50 or less. By using such a cushion, scratches (scratches) on the organic film in the impurity removing step can be reduced. Further, the pad hardness in the present specification means the hardness of the polishing pad.

Although the impurities on the object to be polished can be sufficiently removed by the impurity removing step, the step of removing the impurities remaining on the object to be polished may be further provided after the impurity removing step. For example, at least one of a water polishing step of polishing using water instead of the polishing composition or the impurity removing composition, and a washing step of washing the object to be polished may be provided. The processing content of the washing step is not particularly limited. For example, a step of wiping the water to the object to be polished, or a washing liquid, may be applied by applying a pressure to a brush such as a sponge made of polyvinyl alcohol. The object to be polished after washing may be dried by removing a droplet attached to the surface by a spin dryer or the like.

The composition for removing impurities of the present embodiment is not particularly limited as long as it contains a specific organic compound to be described later, and may contain various additives in addition to a specific organic compound, or may contain abrasive grains. Further, it is also possible to adjust a solution in which an organic compound is dissolved in a solvent. The composition for removing impurities in the present embodiment will be described in detail below.

3-1 About organic compounds

The organic compound contained in the impurity-removing composition of the present embodiment has at least one of a surfactant and a water-soluble polymer. Further, the surfactant has a hydrophilic group and a hydrophobic group having a hydrocarbon group having 3 or more carbon atoms. Further, the water-soluble polymer has a hydrophobic main chain. These organic compounds may be used alone or in combination of two or more.

In the impurity removing step, impurities on the object to be polished are removed by the action of the organic compound. As a mechanism for removing impurities on the object to be polished by the organic compound, it is considered that the adhesion preventing action of the impurities is separated from the impurities.

The adhesion preventing action of impurities is generated by hydrophilizing the surface of the organic film through an organic compound. Further, the detachment action of the impurities is caused by emulsification and hydration of impurities (especially organic substances) adhering to the surface of the organic film by the organic compound.

In the case of adhesion prevention of impurities, when the organic compound has a strong adsorption force to the organic film, since the organic compound itself remains as a residue after polishing, the adsorption of the organic compound on the organic film is too strong. It is suitable. Specifically, the sulfonic acid type surfactant described later has a hydrophilizing action, but since it has a ruthenium remaining as a residue, the effect of reducing the amount of impurities (number of defects) on the surface of the organic film is The surfactants of the sulfuric acid type, the phosphoric acid type, and the carboxylic acid type are relatively weak. On the other hand, the adsorption force of the organic compound on the organic film is too weak, and a hydrophilic film cannot be formed on the surface of the organic film, which may cause a problem that the re-adhesion prevention effect cannot be caused. The organic compound is preferably used to easily adsorb to the organic film (the adsorption speed is fast), and has an easy detachment. Moderate adsorption.

Since the surfactant has a hydrophilic group and a hydrophobic group, the surface of the organic film can be hydrophilized, and the impurities can be emulsified to hydrate. Further, since the water-soluble polymer is hydrophobic in the main chain of the polymer, the surface of the organic film can be hydrophilized, and the impurities can be emulsified and hydrated.

The type of the hydrophilic group of the surfactant is not particularly limited, and examples thereof include a carboxyl group (-COOH), a sulfonic acid group (-SO ₃ H), an ether group (-O-), a hydroxyl group (-OH), and a formazan. At least one of a group (-CHO) and an amine group (-NH ₂ ).

These hydrophilic groups are bonded to a hydrophobic group having a hydrocarbon group having 3 or more carbon atoms, and the hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. When the carbon number of the hydrocarbon group is 3 or more, the surfactant is easily adsorbed to the surface of the organic film by hydrophobic interaction.

As the surfactant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, or a nonionic surfactant can be used.

Specific examples of the nonionic surfactant include polyoxyalkylene alkyl ethers, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, and alkylalkanolamines.

Further, specific examples of the anionic surfactant include coconut oil fatty acid sarcosine, polyoxyethylene alkyl sulfate, alkyl sulfate, polyoxyethylene alkyl ether sulfuric acid, alkyl ether sulfuric acid, and polyoxygen. Vinyl alkyl ether acetic acid, alkyl benzene sulfonic acid, alkyl phosphate, polyoxyethylene alkyl phosphate, polyoxyethylene sulfosuccinic acid, alkyl sulfosuccinic acid, alkyl naphthalene sulfonic acid, alkyl diphenyl Ethyl ether disulfonic acid, or a salt thereof.

On the other hand, since the water-soluble polymer is hydrophobic in its main chain, the main chain does not have an atom which is easily charged with a local charge such as an oxygen atom, a nitrogen atom or a sulfur atom, and is preferably composed only of a carbon atom and a hydrogen atom. Therefore, specific examples of the water-soluble polymer include polyvinyl alcohol, polyglycerin, polyoxyethylene polyglyceryl ether, and polyethylene glycol or polypropylene glycol which are organic compounds contained in the composition for impurity removal.

The content of the organic compound in the impurity-removing composition of the present embodiment is not particularly limited, and may be 0.001% by mass or more and 10% by mass or less. When the amount is 0.001% by mass or more, the hydrophilic portion of the organic compound can sufficiently hydrophilize the surface of the organic film to prevent the impurities from adhering to the surface of the organic film, and the organic substance on the surface of the organic film can be emulsified and discharged into the system. External effect. On the other hand, when it is 10% by mass or less, the organic compound itself is less likely to remain on the surface of the organic film as a residue, and the storage stability of the composition for removing impurities is not easily deteriorated.

3-2 About additives

In the composition for removing impurities in the present embodiment, various additives such as a pH adjuster, an oxidizing agent, a complexing agent, an anticorrosive agent, a preservative, and an antifungal agent may be added as needed to improve the performance. These additives which can be blended in the impurity-removing composition of the present embodiment are the same as those described above in the items 2-3, and thus the description thereof will be omitted.

3-3 About Solvents

As described above, the impurity removing composition of the present embodiment may be adjusted to a solution in which an organic compound is dissolved in a solvent. The type of the solvent is not particularly limited, and examples thereof include water and an organic solvent. These solvents may be used alone or in combination of two or more. It is preferred to contain water. However, it is preferred to use water which does not contain impurities as much as possible from the viewpoint of suppressing the action of hindering an organic compound or an additive. Specifically, it is preferably pure water or ultrapure water or distilled water which is removed by an ion exchange resin and then passed through a filter to remove foreign matter.

3-4 About abrasive grains

The impurity removing composition may or may not contain abrasive grains. When the abrasive grains are contained, a small amount is preferred. When the composition for removing impurities does not contain abrasive grains, other solid matter may not be blended, and the composition for removing impurities may be adjusted into a solution instead of a slurry. Further, when the impurity-removing composition contains abrasive grains, the content thereof is preferably more than 0% by mass and not more than 0.01% by mass. The type of the abrasive grains is not particularly limited, and the above-mentioned abrasive particles in the item 2-1 can be used, but colloidal cerium oxide is preferable. The particle diameter of the abrasive grains is not particularly limited, and abrasive grains having the average primary particle diameter and the average secondary particle diameter described above in the item 2-1 can be used.

[Examples]

The examples and comparative examples are shown below, and the present invention will be more specifically described with reference to Table 1.

(Example 1)

After polishing the object to be polished (chemical mechanical polishing) having an organic film on the surface by using a polishing composition containing abrasive grains, the composition for removing impurities containing an organic compound is polished by a grinder (treatment for removing impurities), To remove impurities present on the object to be polished. Thereafter, the object to be polished is subjected to water polishing by a grinder, and after further washing, the amount of impurities present on the object to be polished is measured.

The object to be polished is a germanium wafer, and a film of a photoresist having an ArF excimer laser (wavelength: 193 nm) as an exposure light source is formed on the surface thereof as an organic film.

The polishing composition is a slurry composed of colloidal cerium oxide (abrasive particles), polyvinylpyrrolidone (additive), and water (liquid medium), and the content of the colloidal cerium oxide in the polishing composition is 2% by mass. The content of the polyvinylpyrrolidone was 0.1% by mass. Further, the colloidal ceria has an average primary particle diameter of 30 nm and an average secondary particle diameter of 60 nm.

The composition for removing impurities was an aqueous solution of pH 7.0 composed of a surfactant (organic compound) and water, and the content of the surfactant in the composition for removing impurities was 0.1% by mass. As a surfactant, as shown in Table 1, coconut oil fatty acid creatinine triethanolamine was used. Coconut oil fatty acid Creatine triethanolamine is an anionic surfactant having a carboxyl group as a hydrophilic group and a hydrocarbon group constituting a coconut oil fatty acid as a hydrophobic group.

As the polishing apparatus, a CMP apparatus F-REX300E (product name) manufactured by Ebara Seisakusho Co., Ltd. was used for the chemical mechanical polishing, the process of removing impurities, and the water polishing. Also, as a polishing pad, In the chemical mechanical polishing, the removal of impurities, and the water polishing, a laminated polishing pad (trade name: IC-1010) made of a foamed polyurethane resin manufactured by ROHM AND HAAS Co., Ltd. was used.

For the polishing conditions, in the chemical mechanical polishing, the polishing pressure was 3.4 kPa (0.5 psi), the rotation speed of the polishing table and the carrier was 10 rpm, the polishing time was 5 seconds, and the supply rate of the polishing composition was 300 ml/min; In the treatment, the polishing pressure was 3.4 kPa (0.5 psi), the polishing speed of the polishing table and the carrier was 30 rpm, the polishing time was 60 seconds, and the supply rate of the impurity-removing composition was 300 ml/min.

The amount of impurities present on the object to be polished was measured using a wafer surface inspection apparatus Surfscan SP1 manufactured by KLA-Tencor. The impurities detected by the device are those having a diameter of 0.5 μm or more. The results are shown in Table 1.

(Examples 2 to 11 and 13)

In the same manner as in Example 1, except that the type of the organic compound used for the impurity-removing composition was changed to the surfactant shown in Table 1, chemical polishing was performed on the object to be polished having an organic film on the surface. After the treatment for removing impurities, water polishing, and washing, the amount of impurities present on the object to be polished is measured. The results are shown in Table 1.

In addition, "POE" such as "POE lauryl ether sulfate" described in Table 1 means "polyoxyethylene"; "POA" of "POA allyl phenyl ether ammonium sulfate" means "polyoxygen" "Alkyl".

(Embodiment 12)

In the same manner as in Example 1, except that the type of the organic compound used for the impurity-removing composition was changed to the water-soluble polymer shown in Table 1, the object to be polished having the organic film on the surface was subjected to chemical mechanical polishing. After the treatment for removing impurities, water polishing, and washing, the amount of impurities present on the object to be polished is measured. The results are shown in Table 1. Further, the polyvinyl alcohol which is a water-soluble polymer has a hydroxyl group as a hydrophilic group and a hydrocarbon group which constitutes a main chain of polyvinyl alcohol as a hydrophobic group.

(Examples 14 to 19)

The type of the organic compound used in the impurity-removing composition was changed to the surfactant shown in Table 1, and the pH was adjusted to 2.7 by adding nitric acid to the impurity-removing composition, and Example 1 was used. In the same manner, after the chemical polishing, the removal of impurities, the water polishing, and the cleaning are performed on the object to be polished having the organic film on the surface, the amount of impurities present on the object to be polished is measured. The results are shown in Table 1.

(Examples 20 to 22)

The type of the organic compound used in the impurity-removing composition was changed to the surfactant shown in Table 1, and ammonia was added to the impurity-removing composition to adjust the pH to 10, and Example 1 was used. In the same manner, after the chemical polishing, the removal of impurities, the water polishing, and the cleaning are performed on the object to be polished having the organic film on the surface, the amount of impurities present on the object to be polished is measured. The results are shown in Table 1.

(Comparative Example 1)

In the same manner as in the first embodiment, chemical polishing, chemical removal, impurity removal, and water polishing were performed on the object to be polished having an organic film on the surface in the same manner as in Example 1 except that the impurity was removed. After washing, the amount of impurities present on the object to be polished is measured. The results are shown in Table 1.

(Comparative examples 2 and 3)

In the same manner as in Example 1, except that the type of the organic compound used for the impurity-removing composition was changed to the surfactant shown in Table 1, chemical polishing was performed on the object to be polished having an organic film on the surface. After the treatment for removing impurities, water polishing, and washing, the amount of impurities present on the object to be polished is measured. The results are shown in Table 1.

As is apparent from the results shown in Table 1, in Examples 1 to 22, the amount of impurities present on the object to be polished was smaller than that of Comparative Examples 1 to 3, and the composition for removing impurities containing the organic compound was passed through a polishing machine. Grinding can completely remove impurities. In Comparative Examples 2 and 3, the main chain of the polymer compound as an organic compound incorporated in the impurity-removing composition is not hydrophobic but hydrophilic, and therefore impurities cannot be sufficiently removed by the treatment of removing impurities.

Claims (12)

A polishing method comprising: a polishing step of polishing an object to be polished having an organic film on a surface thereof using a polishing composition containing abrasive grains; and polishing using the composition for removing impurities containing an organic compound in the polishing step An impurity removal step of removing an impurity present on the polishing target; the organic compound having at least one of a surfactant and a water-soluble polymer, wherein the surfactant has a hydrophilic group and has a hydrophilic group The hydrophobic group of the hydrocarbon group having 3 or more carbon atoms, and the water-soluble polymer has a hydrophobic chain in its main chain. The polishing method of claim 1, wherein the impurity removal composition contains no abrasive particles. The polishing method of claim 1 or claim 2, wherein the polishing rate of the organic film in the impurity removing step is 0.5 nm/min or less. The polishing method according to claim 1 or claim 2, wherein the content of the organic compound in the impurity removing composition is 0.001% by mass or more and 10% by mass or less. The polishing method according to claim 1 or claim 2, wherein the hydrophilic group is at least one selected from the group consisting of a carboxyl group, a sulfonic acid group, an ether group, and a hydroxyl group. A method of producing a substrate comprising the step of polishing a substrate having an organic film on a surface thereof by a polishing method according to claim 1 or claim 2. A substrate by the method of manufacturing the substrate of claim 6 Made. A composition for removing impurities, which is an impurity-removing composition used for removing impurities present on an object to be polished having an organic film on its surface, and an organic compound having a surfactant and a water-soluble substance In at least one of the polymers, the surfactant has a hydrophilic group and a hydrophobic group having a hydrocarbon group having 3 or more carbon atoms, and the water-soluble polymer has a hydrophobic main chain. The composition for removing impurities according to claim 8, which does not contain abrasive grains. The composition for removing impurities according to claim 8 or claim 9, which is used for the object to be polished which has been polished using a polishing composition containing abrasive grains. The composition for removing impurities according to claim 8 or claim 9, wherein the content of the organic compound is 0.001% by mass or more and 10% by mass or less. The composition for removing impurities according to claim 8 or claim 9, wherein the hydrophilic group is at least one selected from the group consisting of a carboxyl group, a sulfonic acid group, an ether group, and a hydroxyl group.