JP2009081302A - Metal polishing composition and polishing method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal polishing composition excellent in polishing speed for a conductor film made of copper or a copper metal and capable of restraining generation of dishing and erosion; and a polishing method using the same. <P>SOLUTION: The metal polishing composition includes (a) a compound represented by formula (I) and (b) peroxodisulfate, and preferably further includes (f) abrasive grains, and is used for chemical mechanical polishing for a conductor film made of copper or a copper alloy in a semiconductor device manufacturing step. In the formula (I), R represents a hydrogen atom, or a substituted or unsubstituted alkyl group. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a metal polishing composition and a polishing method using the same, and more specifically, a metal polishing composition used for planarization of a conductor film in a wiring formation step in semiconductor device manufacturing and polishing using the same. Regarding the method.

In the development of semiconductor devices typified by semiconductor integrated circuits (hereinafter sometimes referred to as “LSI”), in order to increase the integration and speed of semiconductor devices, wiring miniaturization and lamination methods are studied. Has been.
As a technology for this purpose, chemical mechanical polishing (Chemical Mechanical Polishing)
Polishing, hereinafter referred to as “CMP”. Etc.) are employed. CMP is used for polishing an interlayer insulating film (such as SiO 2) and a metal thin film used for wiring to smooth the substrate, or to remove an excess metal thin film at the time of wiring formation (for example, Patent Documents). 1).

A general method of CMP is as follows.
A polishing pad is affixed on a circular polishing platen (platen), and the surface of the polishing pad is immersed in a polishing liquid. The surface of the substrate (wafer) is pressed against the polishing pad, and both the polishing surface plate and the substrate are rotated with a predetermined pressure (polishing pressure) applied from the back surface.
In CMP, the surface of the substrate is flattened by mechanical friction generated by the above operation.

  Conventionally, tungsten and aluminum have been widely used in interconnect structures as wiring metals. However, LSIs using copper, which has lower wiring resistance than these metals, have been developed with the aim of achieving higher performance. As a method for wiring this copper, a damascene method is known (for example, see Patent Document 2). Further, a dual damascene method in which a contact hole and a wiring groove are simultaneously formed in an interlayer insulating film and a metal is embedded in both has been widely used. As a target material for copper wiring, a high-purity copper target of five nines or more is shipped.

  However, in recent years, in order to miniaturize the wiring in accordance with the demand for higher density, improvements in the conductivity and electronic characteristics of the copper wiring are required. On the other hand, the use of a copper alloy obtained by adding a third component to high-purity copper has begun to be studied.

  There is also a need for high-speed metal polishing means that can increase productivity without contaminating these high-definition and high-purity materials. In particular, since copper is a soft metal, when polishing copper or copper alloys, only the center is polished deeper, resulting in dish-like depressions (dishing), or the surface of multiple wiring metal surfaces is a dish. A phenomenon (erosion) that forms a concave-shaped recess and a polishing flaw (scratch) are likely to occur, and an increasingly accurate polishing technique is required.

  In recent years, wafers have become larger in order to improve productivity. Currently, wafers with a diameter of 200 mm or more are widely used, and manufacture of wafers with a diameter of 300 mm or more has started. As the size of the wafer increases, the difference in polishing rate between the central portion and the peripheral portion of the wafer tends to increase, and there is a strong demand for uniform polishing within the wafer surface.

On the other hand, as a chemical polishing method in which mechanical polishing means is not applied to copper and a copper alloy, a chemical polishing method based only on a dissolving action is disclosed (for example, see Patent Document 3).
However, in the chemical polishing method, since polishing is performed only by a chemical dissolution action, problems such as dishing of recesses, that is, dishing, are likely to occur compared to CMP in which the metal film of the protrusions is selectively chemically and mechanically polished. Flatness has become an issue.

In addition, when copper wiring is used in LSI manufacturing, a diffusion prevention layer called a barrier layer is generally provided between the wiring portion and the insulating layer in order to prevent copper ions from diffusing into the insulating material. The barrier layer is formed of a barrier material such as TaN, TaSiN, Ta, TiN, Ti, Nb, W, WN, Co, Zr, ZrN, Ru, CuTa alloy, MnSi _x O _y and MnO _x , one layer or two More layers are provided.
Since these barrier materials have a conductive property, the barrier material on the insulating layer must be completely removed in order to prevent an error such as a leakage current. For this removal processing, a method similar to that for polishing the bulk of the metal wiring material can be applied. This is what is called barrier CMP.

  Further, in the bulk polishing of copper, dishing is likely to occur particularly in a wide metal wiring portion. Therefore, it is desirable that the amount of polishing and removal can be adjusted between the wiring portion and the barrier portion in order to be finally flattened. For this reason, it is desired that the polishing liquid for barrier polishing has an optimal polishing selectivity of copper / barrier metal. Further, since the wiring pitch and the wiring density are different in each level of the wiring layer, it is further desirable that the polishing selectivity can be adjusted as appropriate.

The metal polishing composition (metal polishing liquid) used for CMP generally contains solid abrasive grains (for example, alumina, silica) and an oxidizing agent (for example, hydrogen peroxide, peroxodisulfate).
It is considered that the basic mechanism of CMP using such a metal polishing liquid is that polishing is performed by oxidizing the metal surface with an oxidizing agent and removing the oxide film with abrasive grains (for example, non-polishing). (See Patent Document 1).

A polishing agent containing peroxodisulfate has a feature that a high polishing rate can be obtained, but has a problem that dishing and erosion are likely to proceed. Therefore, as one means for solving this dishing, benzotriazoles are used as an anticorrosive that suppresses polishing of a metal film (see, for example, Patent Document 4).
According to these methods, a protective film is formed on the metal film of the semiconductor substrate, and the metal film is left in the concave portion while the convex portion is removed by the abrasive grains, thereby obtaining a desired conductor pattern. Occurrence of dishing is suppressed by the protective film of the recess, and high flatness is obtained.

However, even when these anticorrosives that provide high flatness as described above are used, the occurrence of erosion due to the corrosion of the barrier film cannot be suppressed, and further improvement is required regarding the flatness required for device manufacturing. This is the current situation.
US Pat. No. 4,944,836 JP-A-2-278822 JP 49-122432 A JP-A-2005-116987 Journal of Electrochemical Society, 1991, Vol. 11, No. 11, pages 3460-3464 Journal of Electrochemical Society, 2000, Vol. 147, No. 10, pages 3907-3913

An object of the present invention is to provide a metal polishing composition that is excellent in the polishing rate of a conductor film made of copper or copper metal and can suppress the occurrence of erosion.
Another object of the present invention is to provide a polishing method that is excellent in the polishing rate of a conductor film made of copper or copper metal and that can suppress the occurrence of erosion.

In view of the above situation, the present inventors have conducted extensive research and found that the above-described problems can be solved by using a tolyltriazole derivative having a specific structure and peroxodisulfate in combination. It was.
That is, the object of the present invention is achieved by the following means.

<1> (a) A compound represented by the following general formula (I), and (b) a peroxodisulfate, used for chemical mechanical polishing of a conductor film made of copper or a copper alloy in a semiconductor device manufacturing process. The metal polishing composition characterized by the above-mentioned.

  In the general formula (I), R represents a hydrogen atom or a substituted or unsubstituted alkyl group.

<2> The metal polishing composition according to <1>, wherein the compound represented by the general formula (I) is a tolyltriazole derivative represented by the following general formula (II): object.

In the general formula (II), X represents an alkylene group, and R ¹ and R ² each independently represents an alkyl group having a carboxyl group, an alkyl group having a hydroxyl group, or an alkyl group.

<3> The metal polishing composition as described in <1>, wherein the compound represented by (a) the general formula (I) is a tolyltriazole derivative having the following structure.

<4> The metal polishing composition according to any one of <1> to <3>, wherein the (b) peroxodisulfate is ammonium peroxodisulfate.
<5> The metal polishing according to any one of <1> to <4>, further comprising (c) one or more compounds selected from the group consisting of organic acids and inorganic acids. Composition.
<6> Further, any one of the above items <1> to <5>, further comprising at least one compound selected from the group consisting of (d) a surfactant and (e) a hydrophilic polymer. The metal polishing composition according to 1.
<7> The metal polishing composition according to <6>, wherein the surfactant (d) is a surfactant having a sulfo group and a phenyl group.
<8> The metal polishing composition according to <6>, wherein the hydrophilic polymer (e) is a water-soluble polymer having an amide bond.

<9> The metal polishing composition according to any one of <1> to <8>, further comprising (f) abrasive grains.
<10> The metal polishing composition according to <9>, wherein the (f) abrasive is silicon oxide.
<11> The metal polishing composition according to <9>, wherein the (f) abrasive is colloidal silica.
<12> The metal polishing composition according to <11>, wherein the colloidal silica has a primary particle diameter of 20 nm to 50 nm.

<13> In the manufacturing process of a semiconductor device, a substrate having a conductor film made of copper or a copper alloy and a barrier film is made of (a) a compound represented by the following general formula (I), and (b) peroxodisulfate A polishing method comprising: chemically and mechanically polishing using a metal polishing composition comprising:

  In the general formula (I), R represents a hydrogen atom or a substituted or unsubstituted alkyl group.

<14> The metal polishing composition is supplied to a polishing pad on a polishing surface plate, and the polishing surface plate is rotated so that the polishing pad moves relative to the surface to be polished while being in contact with the surface to be polished. The polishing method according to <13>, wherein the polishing method is performed.

ADVANTAGE OF THE INVENTION According to this invention, the composition for metal polishing which is excellent in the grinding | polishing speed | rate of the conductor film which consists of copper or copper metal, and can suppress generation | occurrence | production of dishing and erosion can be provided.
Moreover, according to the present invention, it is possible to provide a polishing method that is excellent in the polishing rate of a conductor film made of copper or copper metal and that can suppress the occurrence of dishing and erosion.

[Metal polishing composition]
The metal polishing composition of the present invention includes (a) a compound represented by the general formula (I) and (b) a peroxodisulfate, which is a chemical compound for a conductor film made of copper or a copper alloy in a semiconductor device manufacturing process. It is used for mechanical polishing.
Moreover, you may contain another component as needed.
The metal polishing composition of the present invention usually takes the form of a slurry in which (f) abrasive grains are dispersed in an aqueous solution obtained by dissolving each component.
The metal polishing composition of the present invention is useful for chemical mechanical polishing of an object to be polished having a conductor film made of copper or a copper alloy in a semiconductor device manufacturing process.

  The metal polishing composition of the present invention is a conductor made of copper or a copper alloy by using (a) a tolyltriazole derivative represented by the general formula (I) and further using (b) a peroxodisulfate. The polishing rate of the barrier film can be reduced without reducing the polishing rate of the film. The reason for this is not clear, but it is considered that the tolyltriazole derivative represented by the general formula (I) is selectively adsorbed on the barrier film and suppresses polishing by the metal polishing composition. For this reason, the metal polishing composition of the present invention is excellent in the polishing rate of a conductor film made of copper or copper metal, and can suppress the occurrence of dishing, as well as suppressing barrier layer defects due to the metal polishing composition. In addition, the erosion can also be suppressed.

  Although each component which comprises the metal polishing composition of this invention is explained in full detail below, each component may use only 1 type and may use 2 or more types together.

  In the present invention, the metal polishing composition (hereinafter, also simply referred to as “polishing composition”) is used not only in the composition (concentration) used for polishing but also diluted as necessary during use. The aspect is also referred to as a metal polishing composition in the present invention unless otherwise specified. When the concentrated liquid is used for polishing, it is diluted with water or an aqueous solution and used for polishing, and the dilution ratio is generally 1 to 20 times by volume.

<(A) Compound represented by formula (I)>
The metal polishing composition of the present invention contains (a) a compound represented by the following general formula (I).

In general formula (I), R represents a hydrogen atom or a substituted or unsubstituted alkyl group.
The alkyl group represented by R is preferably an alkyl group having 1 to 4 carbon atoms, and specific examples include a methyl group, an ethyl group, a propyl group, and a butyl group.
Moreover, when R is a substituted alkyl group, examples of the substituent to be introduced include a carboxyl group, a hydroxyl group, an alkyl group, an amino group, a sulfo group, and an alkoxy group. Preferred are a carboxyl group, a hydroxyl group, and an amino group, and more preferred is an amino group. The amino group preferably has a substituted or unsubstituted alkyl group. Examples of the substituent that this alkyl group may have include a carboxyl group, a hydroxyl group, an amino group, a sulfo group, and an alkoxy group. Preferred are a carboxyl group, a hydroxyl group and an amino group, and more preferred is a hydroxyl group.

  As the compound represented by the general formula (I), a compound represented by the following general formula (II) is preferable.

In the general formula (II), X represents an alkylene group, and R ¹ and R ² each independently represents an alkyl group having a carboxyl group, an alkyl group having a hydroxyl group, or an alkyl group.

  The alkylene group represented by X is preferably an alkylene group having 1 to 3 carbon atoms, and specific examples include a methylene group, an ethylene group, a trimethylene group, a propylene group, and an isopropylene group. Among these, a methylene group and an ethylene group are preferable from the viewpoint of sufficiently high CMP rate and erosion suppression.

Examples of the alkyl group having a carboxyl group represented by R ¹ and R ² include a carboxymethyl group, a carboxyethyl group, and a carboxypropyl group. Among them, from the viewpoint of sufficiently high CMP rate and erosion suppression, a carboxymethyl group A carboxyethyl group is preferred.

Examples of the alkyl group having a hydroxyl group represented by R ¹ and R ² include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group. Among these, from the viewpoint of sufficiently high CMP rate and erosion suppression, a hydroxymethyl group A hydroxyethyl group is preferred.

As the alkyl group represented by R ¹ and R ² , an alkyl group having 1 to 3 carbon atoms is preferable, and specific examples include a methyl group, an ethyl group, a propyl group, and an isopropyl group. From the viewpoint of CMP rate and erosion suppression, a methyl group and an ethyl group are preferable.

In the general formula (II), R ¹ and R ² are preferably the same group, and both of them are preferably a hydroxymethyl group and a hydroxyethyl group.

  Specific examples [1-1] to [1-12] of the compound represented by the general formula (I) are shown below, but the present invention is not limited thereto.

  Among these specific examples [I-1] to [I-12], specific examples [I-2], [I-3], [I-5], and [I-8] are preferable from the viewpoint of suppressing erosion. Is preferable, and the specific example [I-8] is particularly preferable.

(A) The addition amount of the compound represented by the general formula (I) is 0.001 mass relative to the total amount of the polishing composition when used for polishing, from the viewpoint of sufficiently high CMP rate and erosion suppression. % To 1.0% by mass, more preferably 0.01% to 0.3% by mass.
Moreover, in this invention, in addition to the compound represented by general formula (I), you may use together the various compounds conventionally used as an anticorrosive of polishing composition. When used together in this way, it is preferable to contain 0.001% by mass or more of the compound represented by the general formula (I) in all the anticorrosives.
Anticorrosives that can be used in combination include 1,2,3,4-tetrazole, 5-amino-1,2,3,4-tetrazole, 5-methyl-1,2,3,4-tetrazole, 1H-tetrazole- 5-acetic acid, 1H-tetrazole-5-succinic acid, 1,2,3-triazole, 4-amino-1,2,3-triazole, 4,5-diamino-1,2,3-triazole, 4-carboxy -1H-1,2,3-triazole, 4,5-dicarboxy-1H-1,2,3-triazole, 1H-1,2,3-triazole-4-acetic acid, 4-carboxy-5-carboxymethyl -1H-1,2,3-triazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, 3-carboxy-1 , 2,4-tri Tetrazole, 3,5-dicarboxy-1,2,4-triazole, 1,2,4-triazole-3-acetic acid, 1H-benzotriazole, 1H-benzotriazole-5-carboxylic acid and the like.

<(B) Peroxodisulfate>
The polishing composition of the present invention contains (b) peroxodisulfate as a compound (oxidant) capable of oxidizing a metal (copper or copper alloy) to be polished.
Among the peroxodisulfates, ammonium peroxodisulfate or potassium peroxodisulfate is preferable, and ammonium peroxodisulfate is most preferable.

  (B) The amount of peroxodisulfate added is preferably 0.003 mol to 0.5 mol, and preferably 0.03 mol to 0.2 mol, per liter of the polishing composition when used for polishing. More preferably, 0.03 mol to 0.1 mol is particularly preferable. That is, the amount of (b) peroxodisulfate added is preferably 0.003 mol or more from the viewpoint of sufficient metal oxidation and ensuring a high CMP rate, and 0.5 mol or less from the viewpoint of preventing roughening of the polished surface.

  The polishing composition of the present invention may contain the following components as necessary in addition to the above-described components. Hereinafter, optional components applicable to the polishing composition of the present invention will be described.

<(C) Organic acid, inorganic acid>
The metal polishing slurry according to the present invention preferably further contains (c) one or more compounds selected from the group consisting of organic acids and inorganic acids. These acids are not metal oxidizers, but have the effect of promoting oxidation, adjusting pH, and buffering agents.
Examples of the inorganic acid include sulfuric acid, nitric acid, boric acid, phosphoric acid, and carbonic acid.

The organic acid is preferably water-soluble. In particular, those selected from the following group are more suitable.
That is, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methyl Hexanoic 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, apple Acid, tartaric acid, citric acid, lactic acid, hydroxyethyliminodiacetic acid, iminodiacetic acid, acedamidoiminodiacetic acid, nitrilotripropanoic acid, nitrilotrimethylphosphonic acid, dihydroxyethylglycine, tricine, and their ammonium salts and alkali metals Examples thereof include salts such as salts, ammonium salts, and mixtures thereof.

An amino acid is also preferably used as one of the organic acids. The amino acid is preferably water-soluble. In particular, those selected from the following group are more suitable.
That is, glycine, L-alanine, β-alanine, L-2-aminobutyric acid, L-norvaline, L-valine, L-leucine, L-norleucine, L-isoleucine, L-alloisoleucine, L-phenylalanine, L- Proline, sarcosine, L-ornithine, L-lysine, taurine, L-serine, L-threonine, L-allothreonine, L-homoserine, L-tyrosine, 3,5-diiodo-L-tyrosine, β- (3 4-dihydroxyphenyl) -L-alanine, L-thyroxine, 4-hydroxy-L-proline, L-cystine, L-methionine, L-ethionine, L-lanthionine, L-cystathionine, L-cystine, L-cysteic acid , L-aspartic acid, L-glutamic acid, S- (carboxymethyl) -L-cysteine, 4-aminobutyric acid Acid, L-asparagine, L-glutamine, azaserine, L-arginine, L-canavanine, L-citrulline, δ-hydroxy-L-lysine, creatine, L-kynurenine, L-histidine, 1-methyl-L-histidine, Examples include 3-methyl-L-histidine, ergothioneine, L-tryptophan, actinomycin C1, apamin, angiotensin I, angiotensin II, and antipine.

In the present invention, the following organic acids are particularly desirable from the standpoint of sufficiently high CMP rate and dishing suppression.
Glycine, iminodiacetic acid, methyliminodiacetic acid, N-methylglycine, nitrilotripropanoic acid, hydroxyethyliminodiacetic acid, L-alanine, β-alanine, glycylglycine, dihydroxyethylglycine, acetamidoiminodiacetic acid, tricine Etc.

  (C) The addition amount of the organic acid or inorganic acid is preferably 0.005 to 0.5 mol, and preferably 0.01 to 0.3 mol in 1 L of the metal polishing liquid used for polishing. Is more preferable, and 0.05 to 0.3 mol is particularly preferable. That is, the organic acid or inorganic acid is preferably 0.01 mol or more in terms of improving the polishing rate, and 0.3 mol or less is preferable in that it does not deteriorate dishing.

In the metal polishing slurry of the present invention, the organic acid or inorganic acid may be used alone or in combination of two or more.
These organic acids can be synthesized according to a conventional method, or commercially available products may be used.

<(D) Surfactant and / or (e) Hydrophilic polymer>
The polishing composition of the present invention can contain (d) a surfactant and / or (e) a hydrophilic polymer.
Both the surfactant and the hydrophilic polymer have the action of reducing the contact angle to the surface to be polished and the action of promoting uniform polishing.

The surfactant that can be used in the present invention is selected from the group of anionic (anionic), cationic (cationic), nonionic (nonionic), and amphoteric (betaine) surfactants. Are preferred.
Examples of the anionic surfactant include carboxylic acid, sulfonic acid, sulfate ester, phosphate ester and salts thereof.
Carboxylic acids and salts thereof include fatty acid salts (for example, beef tallow fatty acid soda, sodium stearate, potassium oleate, castor oil potash), N-acyl amino acid salts (for example, palm oil fatty acid sarcosine triethanolamine), polyoxyethylene Or a polyoxypropylene alkyl ether carboxylate and an acylated peptide are mentioned.

  Examples of sulfonic acids and salts thereof include alkyl sulfonates (for example, dioctyl sulfosuccinate ester salts), alkyl benzene sulfonic acids (for example, dodecyl benzene sulfonic acid (soft), (hard), ammonium dodecyl benzene sulfonate (soft), ( Hard), dodecylbenzenesulfonic acid triethanolamine), alkyl diphenyl ether disulfonate (eg, sodium alkyldiphenyl ether disulfonate), alkyl naphthalene sulfonate (eg, monoisopropyl naphthalene sulfonic acid, diisopropyl naphthalene sulfonic acid, triisopropyl naphthalene sulfone) Acid ammonium), alkylsulfosuccinates (eg sodium dialkylsulfosuccinate, polyoxyethylene lauryl ether) Disodium sulfosuccinate), α-olefin sulfonates, N-acyl sulfonates (for example, coconut oil fatty acid methyl taurine sodium, polyoxyethylene coconut oil aliphatic monoethanolamide sodium sulfate), naphthalene and other aromatic sulfonic acids Formalin condensates (for example, sodium salt of β-naphthalenesulfonic acid formalin condensate, sodium salt of special aromatic sulfonic acid formalin condensate).

Sulfated ester salts such as sulfated oils, alkyl sulfates (for example, sodium lauryl sulfate, higher alcohol sodium sulfate, triethanolamine lauryl sulfate, ammonium lauryl sulfate), alkyl ether sulfates (for example, polyoxyethylene or polyoxypropylene alkyl ether) Examples thereof include sulfates (for example, sodium polyoxyethylene lauryl sulfate, polyoxyethylene lauryl ether sulfate triethanolamine) and alkylamide sulfates.
As phosphate ester salts, alkyl phosphates (eg, potassium octyl phosphate, potassium lauryl phosphate, potassium octyl ether phosphate), polyoxyethylene or polyoxypropylene alkylallyl ether phosphates (eg, polyoxyethylene alkylphenyl ether phosphate) Acid).

Nonionic surfactants include ether type, ether ester type, ester type, and nitrogen-containing type.
The ether type includes polyoxyalkylene alkyl and polyoxyalkylene alkyl phenyl ether (for example, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene higher alcohol ether, Polyoxyethylene myristel ether, polyoxyethylene octyldodecyl ether), polyoxyethylene derivatives (eg, polyoxyethylene disulfonated phenyl ether), polyoxyethylene polyoxypropylene glycol, alkylallyl formaldehyde condensed polyoxyethylene ether, polyoxy Ethylene polyoxypropylene block polymer, polyoxyethylene polyoxypropylene Ruki ether, and the like.

  Ether ester types include glycerin ester polyoxyethylene ether, polyoxyethylene fatty acid ester (eg, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol distearate, polyoxyethylene hydrogenated castor oil), polyoxy Ethylene sorbitan fatty acid ester (for example, polyoxyethylene sorbitan monococonut oil fatty acid ester, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene Oxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sol Tan triisostearate, polyoxyethylene sorbitan mono coconut fatty acid ester, polyoxyethylene sorbit tetraoleate), include polyoxyethylene ethers of sorbitol esters.

Examples of the ester type include sorbitan fatty acid esters (for example, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan sesquioleate), glycerin fatty acid ester ( Examples thereof include glycerol monostearate and glycerol monooleate), polyglycerol ester, sorbitan ester, propylene glycol ester, and sucrose ester.
Examples of the nitrogen-containing type include fatty acid alkanolamide (for example, coconut fatty acid diethanolamide), polyoxyethylene alkylamine (for example, polyoxyethylene laurylamine), polyoxyethylene alkylamide (for example, polyoxyethylene lauric acid amide), and the like. Can be mentioned. Moreover, a fluorine-type surfactant, an acetylene containing nonionic surfactant (For example, diisobutyl dimethyl butynediol polyoxyethylene glycol ether) etc. are mentioned.

  As cationic surfactants, alkylamine salts (for example, coconut amine acetate, stearylamine acetate), quaternary ammonium salts (for example, lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, cetyltrimethylammonium chloride, distearyldimethylammonium) Chloride, alkylbenzyldimethylammonium chloride), alkylpyridinium salts (for example, cetylpyridinium chloride) and the like.

  Amphoteric surfactants include alkylbetaine type (for example, lauric betaine (lauryldimethylaminoacetic acid betaine, stearylbetaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolium betaine), amine oxide type (for example, lauryl). Dimethylamine oxide) and the like.

The surfactant is preferably an anionic surfactant, more preferably a surfactant having a sulfo group, and still more preferably a surfactant having a phenyl group and a sulfo group at the same time. Examples of the surfactant having a phenyl group and a sulfo group at the same time include alkylbenzene sulfonic acid, alkyl diphenyl ether disulfonic acid, and salts thereof, and alkyl diphenyl ether disulfonic acid is particularly preferable.
Examples of the salt include ammonium salts (for example, salts with ammonia and triethanolamine), alkali metal salts (for example, lithium salts, sodium salts, potassium salts), halogens and the like.
However, when the substrate to be polished is a silicon substrate for a semiconductor integrated circuit or the like, contamination with an alkali metal, an alkaline earth metal, a halide, or the like is not desirable, so an acid or an ammonium salt thereof is desirable.

  (E) As the hydrophilic polymer, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene glycol alkyl ether, polyethylene glycol alkenyl ether, alkyl polyethylene glycol, alkyl polyethylene glycol alkyl ether, alkyl polyethylene glycol alkenyl ether, alkenyl polyethylene glycol, Alkenyl polyethylene glycol alkyl ether, alkenyl polyethylene glycol alkenyl ether, polypropylene glycol alkyl ether, polypropylene glycol alkenyl ether, alkyl polypropylene glycol, alkyl polypropylene glycol alkyl ether, alkyl polypropylene glycol alk Ethers such as ruether, alkenyl polypropylene glycol, alkenyl polypropylene glycol alkyl ether and alkenyl polypropylene glycol alkenyl ether; polysaccharides such as alginic acid, pectic acid, carboxymethylcellulose, curdlan and pullulan; amino acid salts; polyaspartic acid, polyglutamic acid, polylysine, Polymalic acid, polymethacrylic acid, polymethacrylic acid ammonium salt, polymethacrylic acid sodium salt, polymaleic acid, polyitaconic acid, polyfumaric acid, poly (p-styrenecarboxylic acid), polyacrylic acid, polyacrylamide, aminopolyacrylamide, polyacrylic Ammonium salt, polyacrylic acid sodium salt, polyamic acid, polyamic acid ammonium salt, polyamic acid sodium salt Polycarboxylic acids and salts thereof such as potassium salt and polyglyoxylic acid; polyvinyl alcohol, vinyl polymers such as polyvinyl pyrrolidone and acrolein and the like.

However, when the substrate to be polished is a silicon substrate for a semiconductor integrated circuit or the like, contamination with alkali metal, alkaline earth metal, halide, etc. is not desirable. In the case of taking a structure, an ammonium salt is desirable. This is not the case when the substrate to be polished is a glass substrate or the like.
Among the above exemplified compounds, the hydrophilic polymer is preferably a hydrophilic polymer having an amide bond, and specifically, polyacrylic acid, polyacrylamide, polyvinyl pyrrolidone, polyvinyl alcohol and the like are preferable.

  The total amount of (d) surfactant and / or (e) hydrophilic polymer added is preferably 0.001 to 10 g in 1 L of the polishing composition when used for polishing. It is more preferable to set it to -5g, and it is especially preferable to set it as 0.01-3g. That is, the addition amount of the surfactant and / or the hydrophilic polymer is preferably 0.001 g or more for obtaining a sufficient effect, and is preferably 10 g or less from the viewpoint of preventing the CMP rate from being lowered.

Only one surfactant may be used, or two or more surfactants may be used in combination. As for the hydrophilic polymer, one kind may be used alone, or two or more kinds may be used in combination.
Moreover, as a weight average molecular weight of these surfactant and / or hydrophilic polymer, 500-100000 are preferable, and 2000-50000 are especially preferable.

<(F) Abrasive grain>
The polishing composition of the present invention can contain (f) abrasive grains.
The abrasive has an action of promoting the CMP rate.
Preferable abrasive grains include, for example, silica (silicon oxide), ceria, alumina, titania, zirconia, germania, manganese oxide and the like, and silica (precipitated silica, fumed silica, colloidal silica, synthetic silica) is particularly preferable. Colloidal silica is more preferable.
As a method for producing colloidal silica particles that can be preferably used as abrasive grains, for example, Si (OC ₂ H ₅ ) ₄ , Si (sec-OC ₄ H ₉ ) ₄ , Si (OCH ₃ ) ₄ , Si (OC ₄ H ₉ ) _{And a} method of hydrolyzing a silicon alkoxide compound such as ₄ by a sol-gel method. The colloidal particles thus obtained have a very sharp particle size distribution.

  The primary particle size of the abrasive grains is a particle size cumulative curve showing the relationship between the particle size of the abrasive grains and the cumulative frequency obtained by integrating the number of particles having the particle size, and the cumulative frequency of this curve is the point at which the cumulative frequency is 50%. It means the particle diameter. For example, LB-500 manufactured by HORIBA, Ltd. is used as a measuring device for obtaining the particle size distribution.

  When the abrasive grains are spherical, the values measured as they are can be adopted. However, the particle size of the amorphous particles is expressed by the diameter of a sphere that is equal to the particle volume. The particle size can be measured by various known methods such as photon correlation method, laser diffraction method, Coulter counter method, etc. In the present invention, observation with a scanning microscope or transmission electron micrograph with a replica method is possible. Is used to obtain and calculate the shape and size of each particle.

  Specifically, the particle thickness is obtained from the projected area of the particle and the shadow of the replica with reference to a diffraction grating of a known length, and the volume of each particle is calculated from these. In this case, although it depends on the particle size distribution, it is desirable to measure and statistically measure 500 or more particles. This method is described in detail in paragraph No. [0024] of JP-A-2001-75222, and the description can be applied to the present invention.

  The average particle size (primary particle size) of the (f) abrasive grains contained in the polishing composition of the present invention is preferably in the range of 20 to 70 nm, more preferably 20 to 50 nm. Particles of 5 nm or more are preferable for the purpose of achieving a sufficient polishing speed. Further, the particle diameter is preferably 50 nm or less for the purpose of not generating excessive frictional heat during polishing.

  In addition, not only the general inorganic abrasive grains as described above but also organic polymer particles can be used in combination as long as the effects of the present invention are not impaired. In addition, colloidal silica surface-modified with aluminate ions or borate ions, colloidal silica with controlled surface potential, such as colloidal silica with various surface treatments, composite abrasive grains composed of multiple materials, etc. It is also possible to use it accordingly.

  The amount of (f) abrasive grains added in the present invention is appropriately selected according to the purpose, but generally used in the range of 0.001 to 20% by mass with respect to the total mass of the metal polishing composition. However, in the present invention, due to the effects of the addition of the components (a) and (b), excellent polishing characteristics can be exhibited even if the amount of abrasive grains added is less than 1.0% by mass. From the viewpoint of suppressing scratches and the like, the addition amount of the abrasive grains is preferably less than 1.0 mass%, more preferably in the range of 0.01 to 0.5 mass%.

<PH of polishing composition>
In the polishing composition of the present invention, due to the reactivity and adsorptivity to the polishing surface, the solubility of the polishing metal, the electrochemical properties of the surface to be polished, the dissociation state of the compound functional group, the stability as a liquid, etc. It is preferable to appropriately set the kind of component, the amount added, or the pH.
The pH of the polishing composition of the present invention is preferably from 3 to 12, more preferably from 8.0 to 12.0 in terms of planarization performance. The pH can be easily adjusted by appropriately selecting and adding a buffer, an alkali agent, an inorganic acid, and the like.

[Raw metal materials]
In the present invention, the semiconductor to be polished is preferably an LSI having wiring made of copper metal and / or copper alloy, and particularly preferably a copper alloy. Furthermore, the copper alloy containing silver is preferable among copper alloys. The silver content contained in the copper alloy is preferably 40% by mass or less, particularly 10% by mass or less, more preferably 1% by mass or less, most preferably in the range of 0.00001 to 0.1% by mass. Exhibits excellent effects.

[Wiring thickness]
In the present invention, the semiconductor to be polished is, for example, 0.15 μm or less, particularly 0.10 μm or less, more preferably 0.08 μm or less in the half pitch in the DRAM device system, and 0.12 μm or less in the MPU device system. In particular, an LSI having a wiring of 0.09 μm or less, more preferably 0.07 μm or less is preferable. For these LSIs, the polishing composition of the present invention exhibits particularly excellent effects.

[Barrier metal]
In the present invention, it is preferable to provide a barrier layer for preventing the diffusion of copper between the wiring in which the semiconductor is made of copper metal and / or a copper alloy and the interlayer insulating film. As the barrier layer, a low-resistance metal material is preferable, and TiN, TiW, Ta, TaN, W, WN, and Ru are particularly preferable, and Ta and TaN are particularly preferable.

[Polishing method]
The polishing composition of the present invention is a concentrated liquid, and when used, is diluted by adding water, or each component is mixed in the form of an aqueous solution described in the next section, and if necessary, In some cases, it is diluted with water to make a working solution or prepared as a working solution.
The polishing method using the polishing composition of the present invention (polishing method of the present invention) can be applied to any case, and has a conductor film made of copper or a copper alloy and a barrier film in a semiconductor device manufacturing process. This is a method of chemically and mechanically polishing a substrate.
In the polishing method of the present invention, the polishing composition of the present invention is supplied to a polishing pad on a polishing surface plate, and the polishing surface plate is rotated so that the polishing pad is made of a conductor film made of copper or a copper alloy. A mode in which polishing is carried out by relative movement while being in contact with a surface to be polished of a substrate having a barrier film is preferable.

As an apparatus for polishing, there is a general polishing apparatus having a polishing surface plate with a holder for holding a semiconductor substrate having a surface to be polished and a polishing pad attached (a motor etc. capable of changing the number of rotations is attached). Can be used.
As the polishing pad, a general nonwoven fabric, foamed polyurethane, porous fluororesin, or the like can be used, and there is no particular limitation.
The polishing conditions are not limited, but the rotation speed of the polishing surface plate is preferably a low rotation of 200 rpm or less so that the substrate does not jump out.
The pressure applied to the polishing pad of the semiconductor substrate having the surface to be polished (film to be polished) is preferably 20 kPa or less. In order to satisfy the uniformity of the polishing rate within the wafer surface and the flatness of the pattern, 6 More preferably, it is ˜15 kPa.

During polishing, the polishing composition is continuously supplied to the polishing pad with a pump or the like. Although the supply amount is not limited, it is preferable that the surface of the polishing pad is always covered with the polishing composition.
After the polishing, the semiconductor substrate is thoroughly washed in running water, and then dried after removing water droplets adhering to the semiconductor substrate using a spin dryer or the like. When the polishing composition of the present invention is used, polishing is performed. The subsequent detergency becomes good. This is presumed to be due to electrostatic repulsion between the abrasive grains and the wiring metal.
In the polishing method of the present invention, the aqueous solution to be diluted is the same as the aqueous solution described below.
The aqueous solution is water containing at least one of an oxidizing agent, an acid, an additive, and a surfactant in advance, and a component obtained by adding up the components contained in the aqueous solution and the components of the polishing composition to be diluted is polished. It becomes a component at the time of grind | polishing using the composition for water.
When diluted with an aqueous solution and used, components that are difficult to dissolve can be blended in the form of an aqueous solution, and a more concentrated polishing composition can be prepared.

As a method of diluting the concentrated polishing composition by adding water, the pipe for supplying the concentrated polishing composition and the pipe for supplying the water are mixed together and mixed, mixed and diluted for polishing. There is a method of supplying a composition to a polishing pad.
Mixing is a method in which liquids collide with each other through a narrow passage under pressure, a method in which a filling such as a glass tube is filled in the pipe, and the flow of liquid is repeatedly separated and merged. Conventional methods such as a method of providing blades that rotate in the above can be employed.

  The supply rate of the polishing composition can be appropriately selected within the range of 10 to 1000 ml / min, but considering the physical properties of the polishing composition of the present invention, it is preferably 400 ml / min or less, preferably 100 to 400 ml / min. A range of min is more preferable.

As a method of diluting and polishing the concentrated polishing composition with an aqueous solution or the like, a pipe for supplying the polishing composition and a pipe for supplying water or an aqueous solution are independently provided, and a predetermined amount of liquid is supplied from each of them. And polishing while mixing by the relative movement of the polishing pad and the surface to be polished.
Alternatively, there is a method in which a predetermined amount of a concentrated polishing composition and water are mixed in one container and then mixed, and then the mixed polishing composition is supplied to a polishing pad for polishing.

In another polishing method of the present invention, the component to be contained in the polishing composition is divided into at least two components, and when these components are used, they are diluted by adding water and supplied to the polishing pad on the polishing platen. In this method, the surface to be polished and the polishing pad are moved relative to each other and brought into contact with the surface to be polished.
For example, an oxidant is one component (A), an acid, an additive, a surfactant, and water are one component (B), and when they are used, the component (A) and the component are made with water. Dilute (B) for use.
In addition, the low-solubility additive is divided into two components (A) and (B), and the oxidizing agent, additive and surfactant are one component (A), and the acid, additive, surfactant and Water is used as one component (B), and when these components are used, water is added to dilute the component (A) and the component (B).
In this example, three pipes for supplying the component (A), the component (B), and water are required, and dilution mixing is performed by combining the three pipes into one pipe that supplies the polishing pad. There is a method of mixing in the pipe. In this case, it is also possible to combine the two pipes and then connect the other one pipe.

For example, this is a method in which a constituent component containing an additive that is difficult to dissolve is mixed with another constituent component, a mixing path is lengthened to ensure a dissolution time, and then a water pipe is further coupled.
Other mixing methods are as described above, in which the three pipes are each guided directly to the polishing pad and mixed by the relative movement of the polishing pad and the surface to be polished, and the three components are mixed in one container. The diluted polishing composition is supplied to the polishing pad.

  In the above polishing method, one constituent component excluding the oxidizing agent is set to 40 ° C. or lower, the other constituent components are heated in the range of room temperature to 100 ° C., and one constituent component and another constituent component or water are added. When diluting and using, it can also be made 40 degrees C or less after mixing. Since solubility becomes high when temperature is high, it is a preferable method for increasing the solubility of raw materials with low solubility of the polishing composition.

  A raw material in which other components not containing an oxidizing agent are heated and dissolved in the range of room temperature to 100 ° C. is precipitated in the solution when the temperature is lowered. It is necessary to dissolve what is deposited by heating. For this, a means for feeding a heated component solution and a means for stirring the liquid containing the precipitate, feeding the liquid, and heating and dissolving the pipe can be employed.

  In the present invention, as described above, the components of the polishing composition may be divided into two or more parts and supplied to the polishing surface. In this case, it is preferable to divide and supply the component containing an oxide and the component containing an acid. Further, the polishing composition may be used as a concentrated liquid and supplied to the polishing surface separately from the dilution water.

〔pad〕
The polishing pad may be a non-foamed structure pad or a foamed structure pad. The former uses a hard synthetic resin bulk material like a plastic plate for a pad.
Further, the latter further includes three types of a closed foam (dry foam system), a continuous foam (wet foam system), and a two-layer composite (laminated system), and a two-layer composite (laminated system) is particularly preferable. Foaming may be uniform or non-uniform.
Further, it may contain abrasive grains (for example, ceria, silica, alumina, resin, etc.) used for polishing. In addition, the hardness may be either soft or hard, and either may be used. In the laminated system, it is preferable to use a different hardness for each layer.
The material is preferably non-woven fabric, artificial leather, polyamide, polyurethane, polyester, polycarbonate or the like.
Further, the surface that contacts the polished surface may be subjected to processing such as lattice grooves / holes / concentric grooves / helical grooves.

[Wafer]
The target wafer to be subjected to CMP with the polishing composition of the present invention preferably has a diameter of 200 mm or more, particularly preferably 300 mm or more. The effect of the present invention is remarkably exhibited when the thickness is 300 mm or more.

  Hereinafter, the present invention will be described by way of examples. The present invention is not limited to these examples.

[Examples 1 to 8]
According to the following composition and the following Table 1, the polishing composition of Examples 1-8 was prepared.
-Polishing composition-
-(A) Compound represented by general formula (I): one described in Table 1 below 0.05% by mass
(B) Peroxodisulfate:
Ammonium peroxodisulfate 1.0% by mass
Potassium peroxodisulfate 1.18% by mass
(C) Organic acid: those listed in the following Table 1 No addition or 0.5% by mass
(D) Surfactant: DBS potassium not added, or 0.3% by mass
(F) Abrasive grains: 0.5% by mass of colloidal silica particles or fumed silica particles
[Colloidal silica particles are PL-3H (primary particle size 35 nm), manufactured by Fuso Chemical Co., Ltd.]
The pH was adjusted to 9.5 using potassium hydroxide.

[Comparative Examples 1-5]
According to the following composition and following Table 1, the polishing composition of Comparative Examples 1-5 was prepared.
-Polishing composition-
-Comparative compound: 0.05 mass% of the compound shown in Table 1 below
(B) 1.0% by mass of ammonium peroxodisulfate
-(C) Organic acid: L-alanine is not added or 0.5% by mass
-(F) Abrasive grains: 0.5% by mass of colloidal silica particles
[PL-3H (primary particle size 35 nm), manufactured by Fuso Chemical Co., Ltd.]
The pH was adjusted to 9.5 using potassium hydroxide.

  Using the polishing compositions (polishing liquids) prepared in Examples 1 to 5 and Comparative Examples 1 to 4, polishing was performed by the following polishing method, and polishing performance (polishing rate, erosion) was evaluated. The evaluation results are shown in Table 1 below.

<Evaluation of polishing rate and polishing rate Cu / barrier film selection ratio>
An apparatus “FREX-300” manufactured by Ebara Corporation was used as a polishing apparatus, and the film provided on the wafer was polished while supplying slurry (polishing composition) under the following conditions, and the polishing rate was calculated.

-Substrate: A Ta film or a Ti film having a thickness of 20 nm is formed on a silicon oxide film by a sputtering method, and then a copper film having a thickness of 50 nm is formed by a sputtering method, and then a copper film having a total thickness of 1000 nm is formed by a plating method. Uses a 12-inch wafer on which a film is formed. Table rotation speed: 104 rpm
-Head rotation speed: 85 rpm (working linear velocity = 2.0 m / s)
・ Polishing pressure: 10.5kPa
Polishing pad: Product number IC-1400 manufactured by Rohm and Haas
(XY-k-grv) + (A21)
・ Slurry supply rate: 300 ml / min

The film thickness was converted from the electrical resistance before and after polishing, and the polishing rate was calculated from this film thickness and polishing time. Specifically, it was calculated using the following formula.
Polishing rate (nm / min) = (thickness of copper film or barrier film before polishing−thickness of copper film or barrier film after polishing) / polishing time Also, from polishing rate of copper film and polishing rate of barrier film The Cu / barrier film selectivity was determined.

As is apparent from Table 1, the polishing compositions of Examples 1 to 8 have a Cu polishing rate equal to or higher than that of Comparative Examples 1 to 5, and the selection of the polishing rate of the Cu / barrier film It can be seen that the ratio is high.
In addition, it is presumed that erosion, which is a phenomenon in which a plurality of wiring metal surface surfaces form dish-shaped recesses, can be suppressed by such a high selection ratio of the Cu / barrier film polishing rate.

Claims (14)

(A) a compound represented by the following general formula (I), and (b) peroxodisulfate, and used for chemical mechanical polishing of a conductor film made of copper or a copper alloy in a semiconductor device manufacturing process. A metal polishing composition.

[In general formula (I), R represents a hydrogen atom or a substituted or unsubstituted alkyl group. ] 2. The metal polishing composition according to claim 1, wherein the compound represented by the general formula (I) is a tolyltriazole derivative represented by the following general formula (II).

[In General Formula (II), X represents an alkylene group, and R ¹ and R ² each independently represents an alkyl group having a carboxyl group, an alkyl group having a hydroxyl group, or an alkyl group. ] 2. The metal polishing composition according to claim 1, wherein the compound represented by the general formula (I) is a tolyltriazole derivative having the following structure.

  The metal polishing composition according to any one of claims 1 to 3, wherein the (b) peroxodisulfate is ammonium peroxodisulfate.   Furthermore, (c) 1 or more types of compounds selected from the group which consists of organic acid and inorganic acid are contained, The metal polishing composition of any one of Claims 1-4 characterized by the above-mentioned. .   Furthermore, it contains 1 or more types of compounds selected from the group which consists of (d) surfactant and (e) hydrophilic polymer, The any one of Claims 1-5 characterized by the above-mentioned. Metal polishing composition.   The metal polishing composition according to claim 6, wherein the surfactant (d) is a surfactant having a sulfo group and a phenyl group.   The metal polishing composition according to claim 6, wherein the hydrophilic polymer (e) is a water-soluble polymer having an amide bond.   Furthermore, (f) abrasive grain is contained, The metal polishing composition of any one of Claims 1-8 characterized by the above-mentioned.   The metal polishing composition according to claim 9, wherein the (f) abrasive grains are silicon oxide.   The metal polishing composition according to claim 9, wherein the (f) abrasive grains are colloidal silica.   The metal polishing composition according to claim 11, wherein the colloidal silica has a primary particle diameter of 20 nm or more and 50 nm or less. In a manufacturing process of a semiconductor device, a substrate having a conductor film made of copper or a copper alloy and a barrier film is made of (a) a compound represented by the following general formula (I), and (b) a metal containing peroxodisulfate A polishing method comprising polishing chemically and mechanically using a polishing composition.

[In general formula (I), R represents a hydrogen atom or a substituted or unsubstituted alkyl group. ]   The metal polishing composition is supplied to a polishing pad on a polishing surface plate, and the polishing surface plate is rotated so that the polishing pad moves relative to the surface to be polished while being in contact with the surface to be polished of the substrate. The polishing method according to claim 13, wherein the polishing method is characterized.