JP5327430B2 - Chemical mechanical polishing aqueous dispersion, method for producing chemical mechanical polishing aqueous dispersion, and chemical mechanical polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: an aqueous dispersion for chemical mechanical polishing, which is not repeatedly used through a simple process while having superior polishing performance for a metal film of copper etc., a barrier metal film of tantalum etc., and an insulating film; a method of manufacturing the aqueous dispersion for the chemical mechanical polishing; and a method for the chemical mechanical polishing. <P>SOLUTION: The inventors find that the subject to be solved can be solved by using (A) abrasive grains; (B) organic acid; and (C) the aqueous dispersion for chemical mechanical polishing, which contains one or more kinds of atoms selected from a group of T, Ti, and Ru, wherein the ratio Rmax/Rmin of the short diameter Rmin to the long diameter Rmax of the abrasive grains is 1.0 to 1.5 and the concentration of the (C) component is 1.0&times;10<SP>1</SP>to 1.0&times;10<SP>3</SP>p.p.m. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an aqueous dispersion for chemical mechanical polishing, a method for producing an aqueous dispersion for chemical mechanical polishing, and a chemical mechanical polishing method.

  Copper damascene wiring mounted on a high-performance LSI is formed using chemical mechanical polishing (hereinafter also referred to as “CMP”). In CMP, after a wiring material is embedded in a groove or the like formed in an insulating material, a desired wiring is formed by removing excess wiring material by chemical mechanical polishing.

  In such a chemical mechanical polishing process, the chemical mechanical polishing aqueous dispersion used for polishing, polishing scraps generated by scraping from each layer material of the semiconductor device formed on the wafer that is the object to be polished, and polishing Polishing wastewater (hereinafter also referred to as “CMP wastewater”) containing polishing scraps and the like generated by scraping from the pad is discharged. Polishing waste contained in such CMP wastewater causes damage to the polishing surface of each layer of the semiconductor device, and polishing waste is reduced when polishing waste accumulates. Therefore, CMP wastewater is an aqueous dispersion for chemical mechanical polishing. As a wastewater treatment without being reused. On the other hand, the amount of use of the chemical mechanical polishing aqueous dispersion has increased dramatically with the recent increase in the degree of integration of semiconductor devices, so that it is required to reduce the discharge amount of CMP waste water.

From the viewpoint of reducing the manufacturing cost of semiconductors while reducing the burden on the environment, the most efficient CMP drainage reduction technique is a technique of reusing a chemical mechanical polishing aqueous dispersion. For example, Patent Document 1 describes a technique for reusing a chemical mechanical polishing aqueous dispersion using an ion removal film, and Patent Document 2 describes a chemical mechanical polishing aqueous dispersion in which abrasive grains are dispersed by a vibrator. A technique for redistribution and reuse is described. Further, Patent Documents 3 and 4 describe a technique of adding a new chemical mechanical polishing aqueous dispersion or additive to the used chemical mechanical polishing aqueous dispersion and regenerating and reusing it. Furthermore, Patent Document 5 describes a method in which coarse particles contained in CMP waste water are removed using centrifugal separation, and the recovered abrasive grains are used again in the CMP chemical mechanical polishing aqueous dispersion.
However, in these recycling systems, metal ions generated by polishing wiring metal such as copper accumulate, and the initial polishing performance and the polishing performance after regeneration change drastically. was there.
JP-A-11-10540 Japanese Patent Laid-Open No. 11-277434 JP 2000-71172 A JP 2001-162534 A JP 2002-170793 A

  The present invention is excellent in polishing performance of a metal film such as copper, a barrier metal film such as tantalum, and an insulating film, and at the same time, an aqueous dispersion for chemical mechanical polishing that can be repeatedly used through a simple process, It is an object of the present invention to provide a method for producing a mechanical polishing aqueous dispersion and a chemical mechanical polishing method.

The present inventors include (A) abrasive grains, (B) organic acids, and (C) one or more atoms selected from the group consisting of Ta, Ti, and Ru, and the major axis of the (A) abrasive grains The ratio Rmax / Rmin / Rmin / Rmin is 1.0 to 1.5, and the component (C) is 1.0 × 10 ^{1 to} 1.0 × 10 ³ ppm. It has been found that the above problem can be solved by using a chemical mechanical polishing aqueous dispersion for polishing the barrier metal layer obtained.

The chemical mechanical polishing aqueous dispersion according to the present invention is characterized in that the (A) abrasive grains are silica.
The chemical mechanical polishing aqueous dispersion according to the present invention further includes (D) a water-soluble polymer.
The chemical mechanical polishing aqueous dispersion according to the present invention is characterized in that (D) the water-soluble polymer has a weight average molecular weight of 50,000 to 500,000.
The aqueous dispersion for chemical mechanical polishing according to the present invention is characterized in that (B) the organic acid is a compound having two or more carboxyl groups.
The chemical mechanical polishing aqueous dispersion according to the present invention further includes a surfactant.

The method for producing a chemical mechanical polishing aqueous dispersion according to the present invention comprises:
(A) recovering the chemical mechanical polishing aqueous dispersion used for polishing;
(B) removing coarse particles in the chemical mechanical polishing aqueous dispersion used for polishing.
The chemical mechanical polishing method according to the present invention is carried out using the chemical mechanical polishing aqueous dispersion of the present invention.

  The present invention is excellent in polishing performance of a metal film such as copper, a barrier metal film such as tantalum, and an insulating film, and at the same time, an aqueous dispersion for chemical mechanical polishing that can be repeatedly used through a simple process, A method for producing a mechanical polishing aqueous dispersion and a chemical mechanical polishing method are provided.

Embodiments according to the present invention will be described below.
In addition, this invention is not limited to the following embodiment, Various modifications implemented in the range which does not change the summary of this invention are also included.

[Aqueous dispersion for chemical mechanical polishing]
The chemical mechanical polishing aqueous dispersion according to the present embodiment contains (A) abrasive grains, (B) an organic acid, and (C) one or more atoms selected from the group consisting of Ta, Ti, and Ru. The ratio Rmax / Rmin of the major axis Rmax and minor axis Rmin of the (A) abrasive grains is 1.0 to 1.5, and the component (C) is 1.0 × 10 ^{1 to} 1.0 × 10 ^3. It is characterized by being in ppm. Hereinafter, each component contained in the chemical mechanical polishing aqueous dispersion according to this embodiment will be described in detail.

<(A) Abrasive grain>
As the abrasive grains (A) used in the chemical mechanical polishing aqueous dispersion according to this embodiment, at least one selected from inorganic particles and organic particles can be included. Examples of inorganic particles include silica, alumina, titania, zirconia, ceria and the like. Organic particles include polyvinyl chloride, polystyrene and styrene copolymers, polyacetal, saturated polyester, polyamide, polycarbonate, polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, and other polyolefins and olefins. Examples thereof include (meth) acrylic resins such as methacrylic copolymers, phenoxy resins, and polymethyl methacrylate, and acrylic copolymers.

The abrasive used in the chemical mechanical polishing aqueous dispersion according to this embodiment is preferably silica.
As silica, silica synthesized by fumed method of reacting silicon chloride, aluminum chloride, titanium chloride etc. with oxygen and hydrogen in the gas phase, silica synthesized by sol-gel method synthesized by hydrolytic condensation from metal alkoxide, Examples thereof include colloidal silica synthesized by an inorganic colloid method in which impurities are removed by purification. Of these, colloidal silica synthesized by an inorganic colloid method in which impurities are removed by purification is particularly preferable. As the colloidal silica, those having an average particle diameter of 100 nm or less can be suitably used from the viewpoint of suppression of erosion and suppression of scratches on the polished surface.

  The ratio (Rmax / Rmin) of the major axis (Rmax) to the minor axis (Rmin) of the (A) abrasive grains is 1.0 to 1.5, preferably 1.0 to 1.4, more preferably 1.0 to 1. 3. When Rmax / Rmin is in the above range, a high polishing rate and a high planarization characteristic can be expressed without causing defects in the metal film or the insulating film. If Rmax / Rmin is greater than 1.5, defects after polishing occur, which is not preferable.

  Here, (A) the major axis (Rmax) of the abrasive grains is the most of the distances connecting the end portions of the images of one independent abrasive grain image taken with a transmission electron microscope. Mean long distance. The minor axis (Rmin) of the abrasive grain means the shortest distance among the distances connecting the end portions of the image of one independent abrasive grain image taken by a transmission electron microscope. .

For example, when the image of one independent abrasive grain 60a photographed by a transmission electron microscope is elliptical as shown in FIG. 4, the major axis a of the elliptical shape is determined as the major axis (Rmax) of the abrasive grain. Then, the elliptical minor axis b is determined as the minor axis (Rmin) of the abrasive grains. As shown in FIG. 2, when an image of one independent abrasive grain 60b photographed by a transmission electron microscope is an aggregate of two particles, the longest distance c connecting the end portions of the image. Is determined as the major axis (Rmax) of the abrasive grains, and the shortest distance d connecting the end portions of the image is determined as the minor axis (Rmin) of the abrasive grains. As shown in FIG. 3, when the image of one independent abrasive grain 60c photographed by a transmission electron microscope is an aggregate of three or more particles, the longest distance connecting the end portions of the image. e is determined as the major axis (Rmax) of the abrasive grains, and the shortest distance f connecting the end portions of the image is determined as the minor axis (Rmin) of the abrasive grains.
For example, by measuring the major axis (Rmax) and minor axis (Rmin) of 50 abrasive grains by the above-described determination method, and calculating the average value of major axis (Rmax) and minor axis (Rmin), the major axis And the ratio of the minor axis (Rmax / Rmin) can be calculated.

  (A) As for the average particle diameter of an abrasive grain, 5-1000 nm is preferable. The average particle diameter of the abrasive grains can be measured with a laser scattering diffraction measuring instrument, or can be calculated from the cumulative particle diameter and number by observing individual particles with a transmission electron microscope. If the average particle size is less than 5 nm, a chemical mechanical polishing aqueous dispersion having a sufficiently high polishing rate may not be obtained. If it exceeds 1000 nm, suppression of dishing and erosion may be insufficient, and (A) a stable aqueous dispersion may not be easily obtained due to sedimentation and separation of abrasive grains. (A) Although the said range may be sufficient as the average particle diameter of an abrasive grain, More preferably, it is 10-700 nm, Most preferably, it is 15-500 nm. When the average particle diameter is within this range, a stable chemical mechanical polishing aqueous dispersion can be obtained in which the polishing rate is high, dishing and erosion are sufficiently suppressed, and particle settling and separation are unlikely to occur.

  The content of the abrasive (A) is 0.03 to 15% by mass, more preferably 0.05 to 10% by mass, when the total amount of the chemical mechanical polishing aqueous dispersion is 100% by mass. It is particularly preferably 0.05 to 5% by mass. (A) When the content of the abrasive grains is less than the above range, a sufficient polishing rate may not be obtained, and it takes a long time to complete the polishing step. On the other hand, when the addition amount of the abrasive grains exceeds the above range, the cost increases, and a stable chemical mechanical polishing aqueous dispersion may not be obtained.

<(B) Organic acid>
The chemical mechanical polishing aqueous dispersion according to this embodiment can adjust the polishing rate by adding an organic acid. For example, the ratio between the rate of polishing a wiring layer made of copper or a copper alloy and the rate of polishing a barrier metal layer made of an alloy containing tantalum, titanium, nitrides or oxides thereof, or tantalum, titanium, etc. Can be adjusted to a ratio according to the purpose.
As the organic acid, a carboxylic acid organic compound is preferable. More preferably, it is a carboxylic acid organic compound having two or more carboxyl groups in the molecule, and examples thereof include maleic acid, succinic acid, phthalic acid, and citric acid. Particularly preferred is a carboxylic acid organic compound having two carboxyl groups in the molecule, for example, maleic acid. Even when an organic acid compound having no carboxyl group is added, a sufficient polishing rate cannot be obtained for the surface to be polished.

The organic acid may be dissociated in the chemical mechanical polishing aqueous dispersion. In that case, in a divalent or higher acid, the dissociation part may be monovalent or higher. Further, the cation of the pair of dissociation part may be a hydrogen ion or a cation derived from an optionally added additive such as an ammonium ion or a potassium ion.
The addition amount of the organic acid is preferably 0.01 to 3% by mass, more preferably 0.05 to 2% by mass, particularly preferably based on the mass of the chemical mechanical polishing aqueous dispersion at the time of use. It is 0.1-1.5 mass%. When the addition amount of the organic acid is less than the above range, a sufficient polishing rate cannot be obtained, and it takes a long time to complete the polishing step. On the other hand, when the addition amount of the organic acid exceeds the above range, the chemical etching effect increases, and the flatness of the surface to be polished may be impaired.

<(C) One or more atoms selected from the group consisting of Ta, Ti, Ru>
The concentration of one or more atoms selected from the group consisting of (C) Ta, Ti, Ru contained in the chemical mechanical polishing aqueous dispersion according to the present invention is 1.0 × 10 ^{1 to} 1.0 × 10 ^3. ppm, preferably 2.0 × 10 ^{1 to} 5.0 × 10 ² ppm, and more preferably 3.0 × 10 ^{1 to} 1.0 × 10 ² ppm. The concentration of one or more atoms selected from the group consisting of (C) Ta, Ti and Ru contained in the chemical mechanical polishing aqueous dispersion according to the present invention is the chemical mechanical polishing aqueous system according to the present invention. It is a weight concentration calculated from the total weight of one or more atoms selected from the group consisting of (C) Ta, Ti, and Ru contained in 100% by mass including all components of the dispersion. The concentration of one or more atoms selected from the group consisting of (C) Ta, Ti, and Ru is determined by the chemical machine according to the present invention by a known method such as atomic absorption analysis or total reflection X-ray fluorescence analysis. It can be quantified from the aqueous dispersion for polishing.

One or more atomic species selected from the group consisting of Ta, Ti, and Ru contained in the chemical mechanical polishing aqueous dispersion of the present invention are the same atomic species as the metal species contained in the barrier metal to be polished. It is preferable to include. If the chemical mechanical polishing aqueous dispersion of the present invention includes the same atomic species as the metal species contained in the barrier metal to be polished, the atomic species selected from the group consisting of Ta, Ti, and Ru can be used. Two or more types may be included.
For example, when the barrier metal film is a Ta film or a TaN film, the chemical mechanical polishing aqueous dispersion of the present invention preferably contains at least Ta. When the barrier metal film is a Ti film or a TiN film, the chemical mechanical polishing aqueous dispersion of the present invention preferably contains at least Ti. When the barrier metal film is a Ru film, a RuOx film or a RuNx film, the chemical mechanical polishing aqueous dispersion of the present invention preferably contains at least Ru. By containing the same kind of metal as the barrier metal film in this way, the amount of change in the concentration of Ta atoms, Ti atoms, and Ru atoms in the chemical mechanical polishing aqueous dispersion when the barrier metal film is polished is suppressed. In addition, stable polishing characteristics can be maintained. For example, when the concentration of one or more atoms selected from the group consisting of Ta, Ti, and Ru contained in the chemical mechanical polishing aqueous dispersion before polishing the barrier metal film is 100% by mass, the barrier metal film is polished. The amount of increase in concentration of Ta atom, Ti atom and Ru atom in the chemical mechanical polishing aqueous dispersion by Ta atom, Ti atom and Ru atom eluted by 1 to 10% by mass, preferably 1.5 to 8% by mass More preferably, it can be suppressed to 2 to 5% by mass, and a change in the polishing characteristics of the chemical mechanical polishing aqueous dispersion can be suppressed during polishing. As a result, it is possible to uniformly polish a semiconductor circuit substrate having a large area to be polished, which is a polishing target of the present invention.

  In the chemical mechanical polishing aqueous dispersion of the present invention, the concentration of one or more atoms selected from the group consisting of Ta, Ti, and Ru is within the above range, so that Ta eluted to the chemical mechanical polishing aqueous dispersion by polishing. It is possible to simplify the process of removing one or more atoms selected from the group consisting of Ti and Ru, and the chemical mechanical polishing aqueous dispersion can be reused. On the other hand, when the concentration of one or more atoms selected from the group consisting of Ta, Ti, and Ru contained in the chemical mechanical polishing aqueous dispersion exceeds the above range, Ta, Ti are formed on the polished wiring. One or more atoms selected from the group consisting of Ru remain attached, and this is not preferable because a decrease in yield due to deterioration of the electrical characteristics of the semiconductor circuit as the object to be polished is induced. Further, when the concentration of one or more atoms selected from the group consisting of Ta, Ti, and Ru contained in the chemical mechanical polishing aqueous dispersion is smaller than the above range, it is composed of Ta, Ti, and Ru for reuse. It is very difficult to remove one or more atoms selected from the group to a concentration before use, and it is difficult to regenerate an aqueous dispersion for chemical mechanical polishing having the same polishing characteristics as the initial characteristics. Absent.

  The chemical mechanical polishing aqueous dispersion of the present invention comprises (C) one or more atoms selected from the group consisting of Ta, Ti, and Ru as a water-soluble inorganic salt or a salt with an organic acid. It can be contained in the polishing aqueous dispersion. As such water-soluble inorganic salts, for example, Ta, Ti, Ru sulfates, chlorides, nitrates, and the like can be used. The salt with an organic acid is preferably blended and contained as a salt or complex with the (B) organic acid contained in the chemical mechanical polishing aqueous dispersion of the present invention. By blending as a salt with the (B) organic acid and further containing the (B) organic acid, the copper ions eluted into the chemical mechanical polishing aqueous dispersion by polishing are added in advance ( B) Since it has the same chemical characteristics as a salt with an organic acid, it does not change the polishing characteristics of the aqueous dispersion for chemical mechanical polishing even if it does not undergo a process of sufficiently removing copper ions when reused. .

<(D) Water-soluble polymer>
The chemical mechanical polishing aqueous dispersion according to this embodiment can impart viscosity to the chemical mechanical polishing aqueous dispersion by adding a water-soluble polymer. That is, the viscosity of the chemical mechanical polishing aqueous dispersion can be controlled by the amount of the water-soluble polymer added. By controlling the viscosity of the chemical mechanical polishing aqueous dispersion, the polishing pressure can be efficiently and uniformly transmitted to the surface to be polished.
The chemical mechanical polishing aqueous dispersion according to the present embodiment may contain a water-soluble polymer as required. Examples of the water-soluble polymer include polyacrylic acid, polymethacrylic acid, polymaleic acid, polyvinyl sulfonic acid, polyallyl sulfonic acid, polystyrene sulfonic acid, and salts thereof; polyvinyl alcohol, polyoxyethylene, polyvinyl pyrrolidone, polyvinyl pyridine , Polyacrylamide, polyvinylformamide, polyethyleneimine, polyvinyloxazoline, polyvinylimidazole, and other vinyl synthetic polymers; hydroxyethylcellulose, carboxymethylcellulose, modified products of natural polysaccharides such as processed starch, etc. Polyacrylic acid is particularly preferred because it can efficiently impart viscosity to the body. These water-soluble polymers can be used alone or in combination of two or more.

The water-soluble polymer may be a homopolymer or a copolymer obtained by copolymerizing two or more monomers. Monomers having a carboxyl group, monomers having a sulfonic acid group, monomers having a hydroxyl group, monomers having a polyethylene oxide chain, monomers having an amino group, monomers having a heterocyclic ring, etc. Can be used.
Examples of the monomer having an amide group include (meth) acrylamide, N-methylolacrylamide, N-2-hydroxyethylacrylamide, acryloylmorpholine, dimethylaminopropylacrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, N -Vinylacetamide, N-vinylformamide, etc. can be used.

As the monomer having a carboxyl group, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and salts thereof can be used. You may use these in the state of an acid anhydride.
As the monomer having a hydroxyl group, vinyl alcohol, allyl alcohol, hydroxyethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, vinyl glycolic acid, or the like can be used. The side chain alkyl chain length and ethylene oxide chain length are not particularly limited.

As the monomer having an amino group, N, N-dimethylaminoethyl (meth) acrylate or the like can be used. The side chain alkyl chain length is not particularly limited, and may be quaternized with various cationizing agents.
As a monomer having a heterocyclic ring, vinyl imidazole, vinyl pyrrolidone, vinyl pyridine, vinyl oxazoline, N-vinyl caprolactam, vinyl pyrrole, vinyl quinoline and the like can be used.
A surfactant having a polymerizable double bond and a sulfonic acid group in the molecule is commercially available, and such a surfactant may be used as a monomer. Examples of such a surfactant include Eleminol JS-2 (manufactured by Sanyo Kasei Co., Ltd.), Latemuru ASK (manufactured by Kao Corporation), and the like.
Other monomers include cyclohexyl (meth) acrylate, styrene, α-methylstyrene, vinyltoluene, p-methylstyrene and other aromatic vinyl compounds, butadiene, isoprene, 2-chloro-1,3-butadiene, 1 -Aliphatic conjugated dienes such as chloro-1,3-butadiene, vinyl cyanide compounds such as (meth) acrylonitrile, and phosphoric acid compounds. The said monomer can be used individually by 1 type or in combination of 2 or more types.

  The weight average molecular weight of the water-soluble polymer is preferably 50,000 to 5,000,000, more preferably 500,000 to 2,500,000. When the weight average molecular weight of the water-soluble polymer is in the above range, the dishing suppression effect can be improved. When the weight average molecular weight of the water-soluble polymer is less than the above range, viscosity cannot be imparted to the chemical mechanical polishing aqueous dispersion, and the effect of suppressing variation in polishing performance within the substrate surface is small. On the other hand, when the weight average molecular weight of the water-soluble polymer exceeds the above range, the stability of the chemical mechanical polishing aqueous dispersion may be impaired. Moreover, since the viscosity of the chemical mechanical polishing aqueous dispersion becomes too high, the chemical mechanical polishing aqueous dispersion supply device may be loaded.

  The addition amount of the water-soluble polymer is preferably 0.005 to 1.2% by mass, more preferably 0.01 to 0.8% by mass, based on the mass of the chemical mechanical polishing aqueous dispersion at the time of use. And particularly preferably 0.02 to 0.3% by mass. If the addition amount of the water-soluble polymer is less than the above range, the chemical mechanical polishing aqueous dispersion is low in viscosity, so that it is not possible to suppress non-uniform polishing performance within the substrate surface. On the other hand, when the addition amount of the water-soluble polymer exceeds the above range, the flatness improvement effect with respect to the addition amount becomes dull, and the flatness improvement effect cannot be obtained, and the cost is increased. In addition, the polishing rate decreases, or the viscosity of the chemical mechanical polishing aqueous dispersion becomes too high, so that the polishing frictional heat increases and the in-plane uniformity is deteriorated.

  The viscosity of the chemical mechanical polishing aqueous dispersion of the present invention is preferably less than 10 mPa · s. This viscosity can be adjusted by controlling the average molecular weight and content of the (D) water-soluble polymer and its salt. When the viscosity of the chemical mechanical polishing aqueous dispersion exceeds the above range, the chemical mechanical polishing aqueous dispersion may not be stably supplied onto the polishing cloth. As a result, the temperature of the polishing cloth rises or polishing unevenness (deterioration of in-plane uniformity) occurs, which may cause variations in the polishing rate and dishing of the metal film and the insulating film.

  When the chemical mechanical polishing aqueous dispersion of the present invention contains (D) a water-soluble polymer, (B) the organic acid and (D) the water-soluble polymer contained in the chemical mechanical polishing aqueous dispersion according to this embodiment. The mass ratio (B) :( D) is preferably 1: 0.01 to 1: 3, more preferably 1: 0.02 to 1: 2, and particularly preferably 1: 0.05. ~ 1: 1. When the mass ratio is smaller than the above range, the etching effect of the organic acid becomes remarkable and the flatness may be impaired. On the other hand, when the mass ratio is larger than the above range, the polishing rate may be significantly reduced.

<Surfactant>
The chemical mechanical polishing aqueous dispersion of the present invention may further contain a nonionic surfactant, an anionic surfactant or a cationic surfactant. Examples of the nonionic surfactant include polyethylene glycol type nonionic surfactants and nonionic surfactants having a triple bond. Specifically, examples of the polyethylene glycol type nonionic surfactant include polyoxyethylene alkyl ether, polyoxypropylene alkyl ether, and polyoxyalkylene alkyl ether. Examples of the nonionic surfactant having a triple bond include acetylene glycol and its ethylene oxide adduct, acetylene alcohol, and the like. Also included are silicone surfactants, polyvinyl alcohol, cyclodextrin, polyvinyl methyl ether, and hydroxyethyl cellulose. Examples of the anionic surfactant include aliphatic soap, sulfate ester salt, and phosphate ester salt. Examples of the cationic surfactant include aliphatic amine salts and aliphatic ammonium salts. These surfactants can be used singly or in combination of two or more.

  These surfactants are contained in an amount of preferably 2% by mass or less, more preferably 0.01 to 2% by mass, based on 100% by mass of the total amount of the chemical mechanical polishing aqueous dispersion. When the amount of the surfactant is less than 0.01% by mass, dishing, erosion and the like may not be sufficiently suppressed, and when the amount of the surfactant exceeds 2% by mass, the polishing rate is decreased. Furthermore, foaming may not be suppressed.

  In the chemical mechanical polishing aqueous dispersion of the present invention, when an anionic surfactant is used, potassium dodecylbenzenesulfonate or ammonium dodecylbenzenesulfonate is preferably used. Potassium dodecylbenzenesulfonate and ammonium dodecylbenzenesulfonate can be prepared by neutralizing dodecylbenzenesulfonate with potassium hydroxide or ammonia. Content of the said potassium dodecylbenzenesulfonate and / or ammonium dodecylbenzenesulfonate can be 0.002-1 mass% with respect to 100 mass% of total amounts of an aqueous dispersion, Preferably it is 0.005. -0.5 mass%, Furthermore, it can be set as 0.007-0.3 mass%. Moreover, both can also be used together. When the content of the surfactant exceeds 1% by mass, the polishing performance such as the polishing rate is lowered, which is not preferable. On the other hand, if it is less than 0.002% by mass, the effect of suppressing erosion is not sufficient.

  In addition, potassium dodecylbenzenesulfonate and / or a portion of ammonium dodecylbenzenesulfonate can be replaced with other surfactants. Examples of other surfactants that can be used at this time include cationic, anionic and nonionic surfactants. Examples of the cationic surfactant include aliphatic amine salts and aliphatic ammonium salts. Examples of the anionic surfactant include fatty acid soaps, carboxylates such as alkyl ether carboxylates, sulfonates such as alkylbenzene sulfonates, alkylnaphthalene sulfonates, α-olefin sulfonates, and higher alcohol sulfates. Examples thereof include ester salts, sulfuric acid ester salts such as alkyl ether sulfates, and phosphoric acid ester salts such as alkyl phosphoric acid esters. Examples of the nonionic surfactant include ether types such as polyoxyethylene alkyl ether, ether ester types such as glycerol ester polyoxyethylene ether, and ester types such as polyethylene glycol fatty acid ester, glycerol ester and sorbitan ester. . When these surfactants are used in combination, the amount used may be less than 10% by mass based on the total amount of potassium dodecylbenzenesulfonate and / or ammonium dodecylbenzenesulfonate and other surfactants. it can.

<PH adjuster>
The chemical mechanical polishing aqueous dispersion according to the present invention may further contain a pH adjuster. An organic acid, a base compound, etc. can be used as a pH adjuster. The organic acid that can be used in the present invention is preferably, for example, glycine, alanine, phenylalanine, histidine, cysteine, methionine, glutamic acid, aspartic acid, or tryptophan. Examples of organic acids include formic acid, lactic acid, acetic acid, tartaric acid, fumaric acid, glycolic acid, phthalic acid, maleic acid, oxalic acid, citric acid, malic acid, anthranilic acid, malonic acid and glutaric acid, and at least one N atom. Examples thereof include organic acids containing a heterocyclic six-membered ring and organic acids containing a heterocyclic compound composed of a five-membered heterocyclic ring. More specifically, quinaldic acid, quinolinic acid, 8-quinolinol, 8-aminoquinoline, quinoline-8-carboxylic acid, 2-pyridinecarboxylic acid, xanthurenic acid, quinurenic acid, benzotriazole, benzimidazole, 7-hydroxy- 5-methyl-1,3,4-triazaindolizine, nicotinic acid, picolinic acid and the like are preferable.
The polishing rate can be controlled by adjusting the pH of the chemical mechanical polishing aqueous dispersion. The pH can be set by appropriately adding acid or alkali while comprehensively considering factors such as electrochemical properties of the surface to be polished and dispersion stability of the abrasive grains.

  The content of the organic acid that can be used in the present invention is preferably 0.001 to 2.0% by mass, and 0.01 to 1.5% when the total amount of the chemical mechanical polishing aqueous dispersion is 100% by mass. Mass% is preferred. When the content of the organic acid is less than 0.001% by mass, Cu dishing may be increased. On the other hand, if it exceeds 2.0 mass%, (A) a stable aqueous dispersion may not be produced due to sedimentation and separation of the abrasive grains.

  As the base compound that can be used in the present invention, either an organic base or an inorganic base can be used. Examples of the organic base include ethylenediamine, ethanolamine, TMAH (tetramethylammonium hydroxide) and the like. Examples of the inorganic base include ammonia, potassium hydroxide and the like, and only one kind of these bases may be used, or two or more kinds may be used in combination.

  These bases can be contained in an amount of 10% by mass or less, particularly 0.001 to 8% by mass, based on 100% by mass of the aqueous dispersion. If the content of the base is in the range of 10% by mass or less, it is preferable because it is excellent in dispersibility and can be a sufficiently stable aqueous dispersion.

  By adding the pH adjusting agent, the chemical mechanical polishing aqueous dispersion of the present invention can be maintained at an optimum pH. The pH of the chemical mechanical polishing aqueous dispersion of the present invention may be appropriately adjusted according to the film quality of the film to be polished. For example, the low dielectric insulating film is a porous film having a dielectric constant of 2.0 to 2.5. In this case, pH 7 to 11 is preferable, and pH 8 to 10 is more preferable.

<Oxidizing agent>
The chemical mechanical polishing aqueous dispersion according to this embodiment can greatly improve the polishing rate by adding an oxidizing agent.
In the chemical mechanical polishing aqueous dispersion according to this embodiment, an oxidant in a broad sense can be applied as the oxidant. For example, an oxidizable metal salt, an oxidizable metal complex, and a non-metallic oxidant can be used. Specifically, peracetic acid, periodic acid, iron ion nitrate, sulfate, EDTA, citrate, potassium ferricyanide, aluminum salt, sodium salt, potassium salt, ammonium salt, quaternary ammonium salt, phosphonium salt, and others Cation salt peroxides, chlorates, perchlorates, nitrates, permanganates, persulfates, and mixtures thereof.

Of these, hydrogen peroxide is particularly preferable as the oxidizing agent. At least a part of hydrogen peroxide is dissociated to generate hydrogen peroxide ions. In the present specification, hydrogen peroxide includes not only molecular hydrogen peroxide but also hydrogen peroxide ions. Shall be.
The addition amount of the oxidizing agent is preferably 0.005 to 5% by mass, more preferably 0.01 to 3% by mass, and particularly preferably the mass of the chemical mechanical polishing aqueous dispersion at the time of use. It is 0.02-1 mass%. When the amount of the oxidizing agent added is less than 0.005% by mass, the effect of chemical etching cannot be obtained, so that a sufficient polishing rate cannot be obtained, and it takes a long time to complete the polishing process. On the other hand, if the addition amount of the oxidizing agent exceeds 5% by mass, the polished surface may be corroded.

[Method for producing chemical mechanical polishing aqueous dispersion]
The chemical mechanical polishing aqueous dispersion of the present invention is a waste liquid after polishing discharged after use of the chemical mechanical polishing aqueous dispersion. (A) The chemical mechanical polishing aqueous dispersion used for polishing is recovered. It can be produced and further recycled by a method for producing a chemical mechanical polishing aqueous dispersion, which comprises a step and (b) a step of removing coarse particles in the chemical mechanical polishing aqueous dispersion used for polishing. Hereinafter, each step will be described in detail.

  The (a) step of recovering the chemical mechanical polishing aqueous dispersion used for polishing can be applied by any method as long as it does not change the dispersion characteristics of the abrasive grains (A). is there. For example, as described in JP-A-11-10540 and JP-A-11-277434, a line for recovering the chemical mechanical polishing aqueous dispersion after use in the polishing is provided in the apparatus and recovered in the buffer tank. May be.

  The step (a) can also be achieved by separating the abrasive grains from the dispersion medium by centrifugal separation, and then adjusting the separated abrasive grains and necessary components to a predetermined concentration again. For example, it can be achieved by separating the (A) abrasive grains using a method as described in JP-A-2002-170793 and adding the necessary components again to the collected abrasive grains.

  The step (b) is selected from the group consisting of (A) the concentration of abrasive grains and (B) the concentration of organic acid, and C) Ta, Ti, Ru contained in the recovered chemical mechanical polishing aqueous dispersion. Any method can be applied as long as it does not change the concentration of one or more atoms. Note that (A) that the concentration of the abrasive grains is not changed means that the content of the abrasive grains (A) before the step (b) is 100% by mass, after the completion of the step (b) ( A) The content of abrasive grains is 100 to 80% by mass, preferably 99 to 90% by mass, and most preferably 98 to 95% by mass. Further, (B) that the concentration of the organic acid does not change means that the content of the concentration of the organic acid (B) before the step (b) is 100% by mass, the step (b) The (A) abrasive grain content after completion is 100 to 80% by mass, preferably 99 to 90% by mass, and most preferably 98 to 95% by mass. Furthermore, C) that the concentration of one or more atoms selected from the group consisting of Ta, Ti and Ru is not changed means that the content of (C) copper ions before the step (b) is 100% by mass. Then, the content of the (C) copper ion after completion of the step (b) is 100 to 80% by mass, preferably 99 to 90% by mass, and most preferably 98 to 95% by mass.

  In the step (b), specifically, a method such as filtration of coarse particles by a mesh or a filter or polishing scraps can be applied. For example, Japanese Patent Application Laid-Open No. 11-10540 and Japanese Patent Application Laid-Open No. 11-277434. The described method can be adapted.

[Chemical mechanical polishing method]
In the chemical mechanical polishing step, an appropriate chemical mechanical polishing aqueous dispersion according to the purpose can be selected depending on the polishing target. The chemical mechanical polishing process according to this embodiment can be divided into a first stage process for mainly polishing the wiring layer and a second stage process for mainly polishing the barrier metal layer. The chemical mechanical polishing aqueous dispersion according to the present invention can be applied particularly to the second step for polishing the barrier metal layer.
Hereinafter, a chemical mechanical polishing method and a semiconductor circuit substrate manufacturing method according to the present embodiment will be described with reference to the drawings. 4A to 4E are cross-sectional views of the semiconductor circuit substrate showing the chemical mechanical polishing process according to this embodiment.

Examples of the wiring substrate having a structure on the surface include a semiconductor substrate before polishing processing, which is obtained in the process of manufacturing a semiconductor device such as a VLSI.
Examples of the metal forming the metal wiring portion and the metal layer include pure metals such as pure tungsten, pure aluminum, and pure copper; alloys of tungsten, aluminum, copper, and the like with other metals. Although the material which comprises a non-wiring part will not be specifically limited if it is a material which has insulation, A silicon oxide, insulating resin, etc. are mentioned. Examples of the metal constituting the barrier metal layer include tantalum, titanium, tantalum nitride, and titanium nitride.

  As the polishing apparatus, a commercially available chemical mechanical polishing apparatus (for example, “EPO-112”, “EPO-222”, manufactured by Ebara Corporation); “LGP-510”, “LGP-”, manufactured by Lapmaster SFT, Inc. 552 "; manufactured by Applied Materials, trade name" Mirra ").

(1) First, a substrate 10 is prepared as shown in FIG. The substrate 10 has a recess 12 for forming a wiring.
(2) As shown in FIG. 4B, a barrier metal layer 20 is formed so as to cover the surface of the substrate 10 and the bottom and inner wall surface of the wiring recess 12. The barrier metal layer 20 can be made of a material such as tantalum or titanium, or a nitride or oxide thereof. The above-mentioned “tantalum or titanium” is not limited to pure tantalum or pure titanium, but also includes alloys such as tantalum-niobium. The nitrides and oxides are not limited to pure products. The barrier metal layer is preferably a layer formed of at least one material selected from tantalum and tantalum nitride. As a film formation method of the barrier metal layer 20, chemical vapor deposition (CVD) is applied.

  (3) As shown in FIG. 4C, a metal for wiring is deposited so as to cover the surface of the barrier metal layer 20 to form a metal layer 30. The metal layer 30 can be made of copper or a copper alloy. The copper alloy may be an alloy containing 95% by weight or more of copper, such as copper-silicon and copper-aluminum. As a method for forming the metal layer 30, physical vapor deposition (PVD) such as sputtering or vacuum vapor deposition can be applied.

  (4) As shown in FIG. 4D, the first stage polishing step is performed. That is, the excess metal layer 30 other than the portion buried in the wiring recess 12 is removed by chemical mechanical polishing using a chemical mechanical polishing aqueous dispersion for polishing a wiring layer made of copper or a copper alloy. . Further, the above method is repeated until the barrier metal layer 20 is exposed.

(5) Finally, as shown in FIG. 4E, a second stage polishing step is performed. That is, the barrier metal layer 20a and the surface of the substrate 10 other than the wiring recess 12 are removed by chemical mechanical polishing using the chemical mechanical polishing aqueous dispersion according to the present embodiment.
Here, when polished under the same conditions, the ratio (R _Cu / R _BM ) between the polishing rate (R _Cu ) of the wiring layer made of copper or copper alloy and the polishing rate (R _BM ) of the barrier metal layer is 0 0.5 to 2 is preferable. More preferably, it is 0.6-1.5, Most preferably, it is 0.7-1.3. When this ratio (R _Cu / R _BM ) is less than 0.5, a sufficient polishing rate cannot be obtained when polishing a wiring layer made of copper or a copper alloy. For this reason, when the removal of the wiring layer is incomplete in the first-stage polishing in the two-stage polishing method, it takes a long time to remove the unnecessary wiring layer in the second-stage polishing. On the other hand, if the ratio (R _Cu / R _BM ) exceeds 2, the wiring layer may be excessively polished, causing dishing, and good damascene wiring may not be formed.

The above "same conditions" means that a specific type of polishing apparatus is used, the rotation speed of the platen and head, polishing pressure, polishing time, type of polishing pad used, and supply of aqueous dispersion per unit time Means the same amount. As long as the conditions are compared under the same conditions, appropriate conditions can be adopted, but it is desirable to adopt actual polishing conditions or conditions close thereto. For example, the platen rotational speed is preferably 20 to 120 rpm, more preferably 30 to 80 rpm. The head rotation speed is preferably 20 to 120 rpm, more preferably 30 to 80 rpm. The ratio of the platen rotational speed / head rotational speed is preferably 0.5 to 2, and more preferably 0.7 to 1.5. The polishing pressure is preferably 50 to 300 g / cm ² , more preferably 100 to 250 g / cm ² . The supply rate of the chemical mechanical polishing aqueous dispersion is preferably 50 to 300 ml / min, more preferably 100 to 200 ml / min.

  The above-mentioned “ratio” of the polishing rate can be calculated from the value of each polishing rate by separately polishing the wiring layer and the barrier metal layer under the same conditions described above. This polishing can be performed using a substrate provided with a wiring layer or a barrier metal layer.

[Example]
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited at all by this Example. In the examples and comparative examples, “parts” and “%” represent “parts by weight” and “mass%”, respectively, unless otherwise specified.

[Preparation Example 1]
(Preparation of fumed silica particle-containing aqueous dispersion)
100 parts by weight of fumed silica particles (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil 90G) are dispersed in 900 parts by weight of ion-exchanged water using an ultrasonic disperser, filtered through a filter having a pore size of 5 μm, and fumed silica particles. An aqueous dispersion (1) of fumed silica containing 10% by mass of was prepared.

[Preparation Example 2]
(Preparation of colloidal silica-containing aqueous dispersion)
A flask was charged with 65 parts by mass of ammonia water having a concentration of 25% by mass, 40 parts by mass of ion-exchanged water, 170 parts by mass of ethanol, and 20 parts by mass of tetraethoxysilane, and the temperature was raised to 60 ° C. while stirring at a rotational speed of 180 rpm. Stirring was continued for 2 hours while maintaining the temperature at 60 ° C. to obtain an alcohol dispersion of colloidal silica particles.
Subsequently, ion-exchanged water was added, the alcohol component was removed by a rotary evaporator, and an aqueous dispersion (2) of colloidal silica containing 10% by mass of colloidal silica particles was prepared. When the colloidal silica particles contained in the aqueous dispersion were observed with a scanning electron microscope, the average primary particle size was 30 nm, and laser diffraction method (manufactured by Horiba, Ltd., dynamic light scattering particle size distribution measuring device, The average secondary particle diameter measured by the model number “HORIBA LB550”) was 65 nm.

[Preparation Example 3]
(Preparation of colloidal silica-containing aqueous dispersion)
A flask was charged with 70 parts by mass of ammonia water having a concentration of 25% by mass, 30 parts by mass of ion-exchanged water, 100 parts by mass of ethanol and 30 parts by mass of tetraethoxysilane, and the temperature was raised to 70 ° C. while stirring at a rotational speed of 180 rpm. Stirring was continued for 2 hours while maintaining the temperature at 70 ° C. to obtain an alcohol dispersion of colloidal silica particles.
Subsequently, ion-exchanged water was added and the alcohol component was removed by a rotary evaporator to prepare an aqueous dispersion (3) of colloidal silica containing 10% by mass of colloidal silica particles. When the colloidal silica particles contained in the aqueous dispersion were observed with a scanning electron microscope, the average primary particle size was 30 nm, and laser diffraction method (manufactured by Horiba, Ltd., dynamic light scattering particle size distribution measuring device, The average secondary particle diameter measured by the model number “HORIBA LB550”) was 75 nm.

[Preparation Example 4]
(Preparation of aqueous solution containing polyacrylic acid)
500 g of a 20% by mass acrylic acid aqueous solution was added dropwise evenly over 8 hours with stirring under reflux in a container having a volume of 2 liters charged with 1,000 g of ion-exchanged water and 1 g of a 5% by mass ammonium persulfate aqueous solution. After completion of the dropwise addition, the solution was further maintained under reflux for 2 hours to obtain an aqueous solution containing polyacrylic acid having a weight average molecular weight (Mw) of 1,100,000.

[Preparation Example 5]
(Preparation of aqueous solution containing polyacrylate)
A 10% by weight polyacrylate P1 (weight average) was obtained by gradually adding a 10% by weight aqueous potassium hydroxide solution to the aqueous solution containing the polyacrylic acid prepared in [Preparation Example 4]. A pH 7.5 aqueous solution containing a molecular weight (Mw) of 1,100,000 potassium polyacrylate) was prepared. The weight average molecular weight (PEG conversion molecular weight) was measured by gel permeation chromatography (device name: LC module-1 manufactured by Waters, detector; 410 type differential refractometer manufactured by Waters).

<Preparation of aqueous dispersion for chemical mechanical polishing>
[Example 1]
An amount of fumed silica aqueous dispersion (1) corresponding to 1.2% by mass in terms of solid content is placed in a polyethylene bottle so that the total amount of the chemical mechanical polishing aqueous dispersion is 100% by mass, One or more selected from the group consisting of (A) abrasive grains, (B) organic acids, other additives, 30% by mass hydrogen peroxide, (C) Ta, Ti, and Ru listed in Table 1 Were added to a predetermined content shown in Table 1 and sufficiently stirred. Incidentally, Ta was added by adding a Ta-containing dispersion obtained by dripping 0.1 g of tantalum pentaethoxide (manufactured by Kosei Chemical Co., Ltd.) into pure 1 Kg vigorously stirred over 1 hour. The Ta concentration described in 1 was adjusted. Ti is listed in Table 1 by adding a Ti-containing dispersion obtained by dripping 1 g of titanium tetraethoxide (manufactured by Kosei Chemical Co., Ltd.) into pure 1 Kg vigorously stirred over 1 hour. The Ti concentration was adjusted. Ru was adjusted to the Ru concentration shown in Table 1 by adding a 1% ruthenium nitrate aqueous solution. While stirring, an aqueous ammonia solution was added so that the chemical mechanical polishing aqueous dispersion pH was 9, and finally ion-exchanged water was added so that the amount of all components was 100% by mass, followed by stirring for 1 hour. Then, the aqueous dispersion for chemical mechanical polishing was obtained by filtering with a filter with a pore diameter of 5 μm. When this chemical mechanical polishing aqueous dispersion was measured for the concentration of each atom by atomic absorption, the Ta atom concentration was 2.0 × 10 ¹ ppm, and the Ru atom concentration was 4.0 × 10 ¹ ppm. Yes, it was confirmed that the concentration of each atom corresponding to the blending amount was contained.

[Examples 2-3, Comparative Examples 1-3]
A chemical mechanical polishing aqueous dispersion used in each example was prepared in the same manner as in the preparation method except that the content of Ta atom, Ti atom, Ru atom, and other compositions were changed to those shown in Table 1. .

<Evaluation of polishing rate ratio>
A chemical mechanical polishing apparatus (manufactured by Applied Materials, model “MIRRA-Mesa”) was equipped with a porous polyurethane polishing pad (Rohm & Haas Co., product number “IC”) and prepared as described above. While supplying the dispersion, the polishing rate measuring substrate described later was subjected to a chemical mechanical polishing treatment under the polishing conditions described later for 1 minute, and the polishing rates of the copper film, the tantalum film, and the insulating film were calculated by the following method. The ratio of the polishing rate of copper film (R _Cu ), the polishing rate of tantalum film (R _Ta ), and the polishing rate of insulating film (R _TEOS ) has a value of R _Cu / R _Ta (rate ratio) of 0.3-2. .5 is preferable, 0.5 to 1.5 is more preferable, and 0.8 to 1.4 is most preferable. Also. The value (rate ratio) of R _Cu / R _TEOS is preferably 0.3 to 2.5, more preferably 0.5 to 1.5, and most preferably 0.8 to 1.4. Furthermore, in order to judge that the polishing characteristics are good, the ratio between the two polishing rates needs to be within the above-mentioned preferable range.

(A) Substrate for polishing rate measurement A copper film by a sputtering method, a tantalum film by a sputtering method, and a TEOS film (insulating film) by a plasma method are formed on a substrate surface having a diagonal dimension of 2000 mm, and each has a maximum dimension of 2000 mm. A substrate with a copper film, a substrate with a tantalum film having a maximum dimension of 2000 mm, and a substrate with a plasma TEOS film (oxide film) having a maximum dimension of 2000 mm were prepared.

(B) Polishing conditions and polishing pad: manufactured by Rodel, trade name: IC1000
Head load: 200 g / cm ²
-Head rotation speed: 60 rpm
・ Surface plate speed: 65rpm
-Supply speed of chemical mechanical polishing aqueous dispersion: 150 mL / min

(C) Polishing rate calculation method The polishing rate was calculated by the following formula (1).
Polishing rate (nm / min)
= (Thickness of each film before polishing-Thickness of each film after polishing) / Polishing time (1)
The thickness of the copper film and the tantalum film was measured by using a conductive film thickness measuring device (model OMNIMAP RS75, manufactured by KLA-Tencor Corporation), and chemical mechanical polishing. The polishing rate was calculated by the above formula (1) from the film thickness and the polishing time reduced by.
For the insulating film, the film thickness after polishing treatment was measured by using an optical interference type film thickness measuring device (model “Nanospec6100” manufactured by Nanometrics Japan), and the film thickness and polishing time decreased by chemical mechanical polishing. From the above, the polishing rate was calculated by the formula (1).

  Table 1 shows the compositions of the chemical mechanical polishing aqueous dispersions used in Examples 1 to 3 and Comparative Examples 1 to 3, and the results of the polishing performance evaluation of the copper film as “polishing results”.

<Reuse polishing evaluation of aqueous dispersion for chemical mechanical polishing>
The chemical mechanical polishing aqueous dispersion used in <Evaluation of polishing rate ratio> is a Hitachi high-speed cooling centrifuge CR22E manufactured by Hitachi Koki Co., Ltd., and a continuous rotor R18C for the centrifuge is used as a rotor. Centrifugation was performed under the conditions of a maximum centrifugal acceleration of 1000 G and a rotation time of 10 minutes, and the abrasive grains were collected by sedimentation. Assuming that all the abrasive grains were recovered without drying the recovered abrasive grains, (A) abrasive grains, (B) so that the total amount of the chemical mechanical polishing aqueous dispersion becomes 100% by mass again. 1) One or more atoms selected from the group consisting of organic acid, other additives, 30% by mass hydrogen peroxide, (C) Ta, Ti, and Ru are added so as to have a predetermined content shown in Table 1. And stirred well. Incidentally, Ta was added by adding a Ta-containing dispersion obtained by dripping 0.1 g of tantalum pentaethoxide (manufactured by Kosei Chemical Co., Ltd.) into pure 1 Kg vigorously stirred over 1 hour. The Ta concentration described in 1 was adjusted. Ti is listed in Table 1 by adding a Ti-containing dispersion obtained by dripping 1 g of titanium tetraethoxide (manufactured by Kosei Chemical Co., Ltd.) into pure 1 Kg vigorously stirred over 1 hour. The Ti concentration was adjusted. Ru was adjusted to the Ru concentration shown in Table 1 by adding a 1% ruthenium nitrate aqueous solution. While stirring, an aqueous ammonia solution was added so that the chemical mechanical polishing aqueous dispersion pH was 9, and finally ion-exchanged water was added so that the amount of all components was 100% by mass, followed by stirring for 1 hour. Then, it filtered with a 10 micrometers filter, and created the chemical mechanical polishing aqueous dispersion.

  Using the chemical mechanical polishing aqueous dispersion thus prepared, the results used in the above <Evaluation of polishing rate of copper film> are shown in Table 1 as "Reuse polishing results".

In the chemical mechanical polishing aqueous dispersions of Examples 1 to 3, the polishing rate was sufficiently high at 33 nm / min or more for any material film (Cu, Ta, oxide film), and polishing of the wiring material film and the tantalum film was performed. The speed ratio is 0.91 to 1.12. On the other hand, the polishing speed ratio between the wiring material film and the insulator is 0.93 to 1.03, and any polishing speed ratio is appropriate. It can be seen that flatness is obtained. Moreover, the reuse result is also good and it is clear that it can be reused.
Comparative Example 1 is an example in which one or more atoms selected from the group consisting of (C) Ta, Ti, and Ru are contained exceeding the upper limit of the present invention, the polishing rate is not sufficient, and the polishing rate ratio Is also not a preferable value.
Comparative Example 2 is an example in which one or more atoms selected from the group consisting of (C) Ta, Ti, and Ru are not included, and any polishing rate ratio is not appropriate, and good flatness is obtained. I can't.
In contrast, Comparative Example 3 does not contain (B) an organic acid, and (C) the amount of one or more atoms selected from the group consisting of Ta, Ti, and Ru is less than the lower limit of the present invention. Not contained, Rmax / Rmin is an example out of the range of the present invention, the polishing rate of the barrier metal layer is not sufficient, and the polishing rate ratio is not a preferable value.
As described above, the chemical mechanical polishing aqueous dispersions of Comparative Examples 1 to 3 cannot achieve the object of the present invention.

It is the conceptual diagram which showed the major axis and minor axis of the abrasive grain typically. It is the conceptual diagram which showed the major axis and minor axis of the abrasive grain typically. It is the conceptual diagram which showed the major axis and minor axis of the abrasive grain typically. (A) thru | or (E) are sectional drawings of the semiconductor circuit board which shows the process of the chemical mechanical polishing which concerns on this Embodiment.

Explanation of symbols

60a, 60b, 60c ... abrasive grains 10 ... substrate, 12 ... recess for wiring, 20 / 20a ... barrier metal layer, 30 ... metal layer

Claims (8)

(A) abrasive grains, (B) and an organic acid, (C) Ta, containing at least one atom selected from the group consisting of Ti and Ru, and said component (C) of atoms of the same type An aqueous dispersion for chemical mechanical polishing for polishing a barrier metal film containing a metal species of
(A) the ratio Rmax / Rmin of the abrasive grains of diameter Rmax and minor Rmin is 1.0 to 1.5,
An aqueous dispersion for chemical mechanical polishing , wherein the concentration of the component (C) is 1.0 × 10 ^{1 to} 1.0 × 10 ³ ppm. The abrasive grains (A) is silica, the chemical mechanical polishing aqueous dispersion according to 請 Motomeko 1. (D) The chemical mechanical polishing aqueous dispersion according to claim 1 or 2, further comprising a water-soluble polymer.   The chemical mechanical polishing aqueous dispersion according to claim 3, wherein the (D) water-soluble polymer has a weight average molecular weight of 50,000 to 5,000,000. The chemical mechanical polishing aqueous dispersion according to any one of claims 1 to 4, wherein the organic acid (B) is a compound having two or more carboxyl groups. The chemical mechanical polishing aqueous dispersion according to any one of claims 1 to 5 , further comprising a surfactant. (A) recovering the chemical mechanical polishing aqueous dispersion used for polishing the barrier metal film containing at least one metal species selected from the group consisting of Ta, Ti and Ru ;
Removing the (b) the chemical mechanical polishing aqueous coarse particles in the dispersion,
A process for producing an aqueous dispersion for chemical mechanical polishing according to any one of claims 1 to 6, comprising: Chemical mechanical polishing method using the chemical mechanical polishing aqueous dispersion according to claims 1 or one of claims 6.

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