JP2010045258A - Metal polishing liquid and chemical mechanical polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal polishing liquid capable of obtaining a high polishing speed when polishing a polishing target (wafer) in a semiconductor device manufacturing process and capable of suppressing variation in the polishing speed of the metal polishing liquid resulting from the lapse of time and to provide a chemical mechanical polishing method using the metal polishing liquid. <P>SOLUTION: The metal polishing liquid contains (I) an organic acid, (II) a passive film forming agent, (III) abrasive grains, (IV) oxidant, and (V) a compound represented by a general formula (A) or a general formula (B). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a metal polishing liquid used for chemical mechanical planarization in a semiconductor device manufacturing process, and a chemical mechanical polishing method using the same.

In recent years, in the development of semiconductor devices represented by semiconductor integrated circuits (hereinafter referred to as LSI), in recent years, there has been a demand for higher density and higher integration by miniaturization and stacking of wiring in order to reduce size and speed. Yes. For this purpose, various techniques such as chemical mechanical polishing (hereinafter referred to as CMP) have been used.
This CMP is an indispensable technique for performing surface flattening of a film to be processed such as an interlayer insulating film, plug formation, formation of embedded metal wiring, etc., and this technique is used to smooth a substrate or form a wiring. The excess metal thin film is removed (for example, refer to Patent Document 1).

A general method of CMP is to apply a polishing pad on a circular polishing platen (platen), immerse the surface of the polishing pad with a polishing liquid, press the surface of the substrate (wafer) against the pad, and apply a predetermined pressure from the back surface. In a state where (polishing pressure) is applied, both the polishing platen and the substrate are rotated, and the surface of the substrate is flattened by the generated mechanical friction.
The metal polishing solution used for CMP generally contains abrasive grains (eg, alumina, silica) and an oxidizing agent (eg, hydrogen peroxide, persulfuric acid). It is considered that the basic mechanism is that the metal surface is oxidized by an oxidizing agent and the oxide film is polished by abrasive grains, and the method is described in Non-Patent Document 1, for example. Yes.

  Conventionally, tungsten and aluminum have been widely used in interconnect structures as wiring metals. However, LSIs using copper, whose wiring resistance is smaller than these metals, have been developed with the aim of achieving higher performance. As a method of wiring this copper, for example, a damascene method described in Patent Document 2 is known. 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. In the polishing of copper metal, since it is a particularly soft metal, a highly accurate polishing technique is increasingly required. At the same time, a high-speed metal polishing means capable of exhibiting high productivity is demanded.

Furthermore, recently, from the viewpoint of production stability, there is a strong demand for the temporal stability of a polishing liquid to which an oxidizing agent is added before polishing.
In response to this requirement, in order to improve the temporal stability of a metal polishing liquid used in CMP containing hydrogen peroxide, for example, a technique using a polishing liquid containing ammonium carbonate or the like is known (for example, Patent Document 3). reference.). However, even with these technologies, it is still insufficient, and development of a technology that satisfies both high-speed polishing properties and stability over time is awaited.
US Pat. No. 4,944,836 JP-A-2-278822 Japanese Patent Laid-Open No. 10-310766 Journal of Electrochemical Society, 1991, 138, 11, 3460-3464

The present invention has been made in view of the above-described problems, and an object thereof is to achieve the following object.
That is, an object of the present invention is to obtain a high polishing rate when polishing an object to be polished (wafer) in a semiconductor device manufacturing process, and to suppress fluctuations in the polishing rate over time of the metal polishing liquid. Another object of the present invention is to provide a metal polishing liquid and a chemical mechanical polishing method using the same.

As a result of intensive studies, the present inventor has found that the above problems can be solved by the following metal polishing liquid and a chemical mechanical polishing method using the same, and have completed the present invention.
The metal polishing liquid of the present invention and the chemical mechanical polishing method using the same are as follows.

<1> (I) Organic acid, (II) Passive film forming agent, (III) Abrasive grain, (IV) Oxidizing agent, and (V) The following general formula (A) or general formula (B) Polishing liquid for metals containing a compound.

In general formula (A), R ¹ represents a hydrogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group, and Q represents a linking group that can form a 5-membered ring or a 6-membered ring. .

In general formula (B), R ² represents a hydrogen atom, a hydroxy group, a carboxyl group, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group, and A represents a carbonyl group, a sulfoxide, or a sulfone group. M represents a hydrogen atom or an alkali metal.
<2> The metal polishing slurry according to <1>, wherein the compound represented by the general formula (A) is a compound represented by the following general formula (C).

In general formula (C), R ³ and R ⁴ each independently represent a hydrogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a heterocyclic group, an amino group, or a carboxyl group, which are connected to form a ring. May be formed.

<3> The metal polishing slurry according to <1>, wherein the compound represented by the general formula (B) is a compound represented by the following general formula (D).

In general formula (D), R ⁵ represents a hydrogen atom, a hydroxy group, a carboxyl group, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group, and M represents a hydrogen atom or an alkali metal.

<4> The metal polishing slurry according to any one of <1> to <3>, wherein the (II) passivating film forming agent is benzotriazole or a derivative thereof.
<5> The metal polishing slurry according to any one of <1> to <3>, wherein the (II) passivating film forming agent is 1,2,3-triazole and derivatives thereof.
<6> The metal polishing slurry according to any one of <1> to <3>, wherein the (II) passivating film forming agent is 1,2,4-triazole and derivatives thereof.

<7> The metal polishing slurry according to any one of <1> to <4>, wherein the (II) benzotriazole as a passive film forming agent and a derivative thereof are represented by the following general formula (E):

In general formula (E), R ⁶ represents a methyl group, a carboxyl group, or a sulfo group. n represents an integer of 0 to 2. R ⁷ represents a hydrogen atom, an alkyl group containing a carboxyl group, an alkyl group containing a hydroxy group, or an alkyl group containing both a hydroxy group and an amino group.

<8> (1) A step of supplying the metal polishing liquid according to any one of <1> to <7> to a polishing pad on a polishing surface plate and rotating the polishing surface plate (2) the polishing A chemical mechanical polishing method comprising a step of polishing a pad by moving it relative to the surface to be polished while being in contact with the surface to be polished.

  According to the present invention, when polishing an object to be polished (wafer), a high polishing rate is obtained, and the metal polishing liquid in which the fluctuation of the polishing speed over time of the metal polishing liquid is suppressed, and the The chemical mechanical polishing method used can be provided.

Hereinafter, specific embodiments of the present invention will be described.
<Metal polishing liquid>
The metal polishing slurry of the present invention comprises, as essential components, (I) an organic acid, (II) a passive film forming agent, (III) abrasive grains, (IV) an oxidizing agent, and (V) the following general formula (A) Or a compound represented by the general formula (B) (hereinafter, the compound represented by the general formula (A) and the compound represented by the general formula (B) may be collectively referred to as “specific cyclic compound”). , Containing. Usually, it takes the form of a slurry in which abrasive grains are dispersed in an aqueous solution in which components other than the oxidizing agent are dissolved. However, the present invention is not limited to this form.

<(V) Specific cyclic compound (compound represented by general formula (A) or general formula (B))>
The metal polishing slurry of the present invention contains one or more compounds represented by the following general formula (A) or general formula (B). By including this specific cyclic compound, the metal polishing slurry of the present invention can suppress fluctuations in the polishing rate over time. The compounds of general formula (A) and general formula (B) which are the specific cyclic compounds will be described below.

R ¹ in the general formula (A) represents a hydrogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group, and Q represents a linking group that can form a 5-membered ring or a 6-membered ring. Represented (except 5 tetrazole 5 uracil).

The aliphatic hydrocarbon group for R ¹ in the general formula (A) has 1 to 20 carbon atoms and may be substituted with a hydroxy group, an amino group, a carboxyl group, or the like. Further, it may be branched or linear.
The aromatic hydrocarbon group for R ¹ is a phenyl group or a naphthyl group having 6 to 20 carbon atoms, and a methyl group, a hydroxy group, an amino group, or the like may be substituted.
The heterocyclic group is a pyridyl group, a furyl group, or an imidazolyl group. The heterocyclic group may be substituted with a methyl group, a hydroxy group, an amino group, a carboxyl group or the like.

Specific examples of the aliphatic hydrocarbon group represented by R ¹ in the general formula (A) include a methyl group, an ethyl group, an n-propyl group, a hydroxyethyl group, and a carboxymethyl group, and an aromatic hydrocarbon group represented by R ^1. Specific examples thereof include a phenyl group, a 4-methylphenyl group, a naphthyl group, and a 4-carboxyphenyl group.

  Specific compounds of the general formula (A) include ethylene urea, theobromine, cyanuric acid, uracil, xanthine, methyluracil, orotic acid, uric acid, glycoluril, hydantoin, allantoin, N-methylethyleneurea, N-hydroxyethyl. Ethylene urea, barbituric acid, N-phenyl barbituric acid, N-methyl glycoluril, and the like.

  Of the compounds of general formula (A), compounds represented by the following general formula (C) are more preferably used in the present invention.

R ³ and R ⁴ in the general formula (C) each independently represent a hydrogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a heterocyclic group, an amino group, or a carboxyl group, and they are connected as much as possible. To form a ring.

The aliphatic hydrocarbon group represented by R ³ and R ⁴ in the general formula (C) has 1 to 16 carbon atoms, and may be substituted with a hydroxy group, an amino group, a carboxyl group, or the like. Further, it may be branched or linear.
The aliphatic hydrocarbon group is preferably a methyl group, an ethyl group, or a hydroxyethyl group.
The aromatic hydrocarbon group for R ³ and R ⁴ is a phenyl group or a naphthyl group having 6 to 20 carbon atoms, and a hydroxy group, an amino group, a carboxyl group, or the like may be substituted. The aromatic hydrocarbon group is preferably a phenyl group, a 4-methylphenyl group, a naphthyl group, or a 4-carboxyphenyl group.
Examples of the heterocyclic group include a pyridyl group, a furyl group, and an imidazolyl group. The heterocyclic group may be substituted with a hydroxy group, an amino group, or a carboxyl group. A heterocyclic group is preferably a pyridyl group.

Specific examples of the aliphatic hydrocarbon group represented by R ³ and R ⁴ in the general formula (C) include a methyl group, an ethyl group, and a hydroxyethyl group, and preferably a methyl group.
Specific examples of the aromatic hydrocarbon group for R ³ and R ⁴ are a phenyl group, a hydroxyphenyl group, a carboxyphenyl group, and a naphthyl group, and preferably a phenyl group.

  Specific compounds of the general formula (C) are ethylene urea, 4,5-dicarboxyethylene urea, glycoluril, N-methylglycoluril and the like, and preferable compounds are ethyleneurea, uric acid, glycoluril. .

R ² in the general formula (B) represents a hydrogen atom, a hydroxy group, a carboxyl group, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group, and A represents a carbonyl group, a sulfoxide, or a sulfone group. To express. M represents hydrogen or an alkali metal.

The aliphatic hydrocarbon group represented by R ² in the general formula (B) has 1 to 16 carbon atoms and may be substituted with a hydroxy group, an amino group, a carboxyl group, or the like. Further, it may be branched or linear.
The aromatic hydrocarbon group for R ² is a phenyl group or a naphthyl group having 6 to 20 carbon atoms, and a hydroxy group, an amino group, a carboxyl group, or the like may be substituted.
Examples of the heterocyclic group include a pyridyl group, a furyl group, and an imidazolyl group. The heterocyclic group may be substituted with a hydroxy group, an amino group, or a carboxyl group.
Examples of the alkali metal of M are sodium and potassium.

Specific examples of the aliphatic hydrocarbon group represented by R ² in the general formula (B) include a methyl group, an ethyl group, and an n-butyl group. Specific examples of the aromatic hydrocarbon group represented by R ² include a phenyl group. 4-methylphenyl group, naphthyl group, 4-carboxyphenyl group. A specific example of the heterocyclic group is a pyridyl group.

  Specific compounds of the general formula (B) include saccharin, phthalimide, methylphthalimide, hydroxyphthalimide, carboxyphthalimide, phenylphthalimide, and the like.

  Of the compounds of general formula (B), compounds represented by the following general formula (D) are more preferably used in the present invention.

R ⁵ in the general formula (D) represents a hydrogen atom, a hydroxy group, a carboxyl group, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group. M represents a hydrogen atom or an alkali metal.

The aliphatic hydrocarbon group represented by R ⁵ in the general formula (D) has 1 to 16 carbon atoms and may be substituted with a hydroxy group, an amino group, a carboxyl group, or the like. Further, it may be branched or linear.
The aromatic hydrocarbon group is a phenyl group or a naphthyl group having 6 to 20 carbon atoms, and a hydroxy group, an amino group, a carboxyl group, or the like may be substituted. The aromatic hydrocarbon group is preferably a phenyl group, a 4-methylphenyl group, a naphthyl group, or a 4-carboxyphenyl group.
Examples of the heterocyclic group include a pyridyl group, a furyl group, and an imidazolyl group. The heterocyclic group may be substituted with a hydroxy group, an amino group, or a carboxyl group. A heterocyclic group is preferably a pyridyl group.
Examples of the alkali metal of M are sodium and potassium.

Specific examples of the aliphatic hydrocarbon group represented by R ⁵ in the general formula (D) include a methyl group, an ethyl group, and an n-butyl group. Specific examples of the aromatic hydrocarbon group represented by R ⁵ include a phenyl group. A naphthyl group.

  Specific compounds of the general formula (D) include phthalimide, methyl phthalimide, n-butyl phthalimide, hydroxy phthalimide, carboxy phthalimide, phenyl phthalimide, and the like. A preferred compound is phthalimide.

  Specific examples of preferred compounds of the (V) specific cyclic compound (compound represented by formula (A) or formula (B)) used in the present invention are shown below. By adding the specific cyclic compound, it is possible to suppress fluctuations in the polishing rate over time of the metal polishing liquid. However, it is not limited to these.

The compounds of the general formula (A) among the above compounds are ethylene urea, theobromine, cyanuric acid, uracil, xanthine, methyluracil, orotic acid, uric acid, glycoluril, hydantoin, and allantoin. More preferred compounds are those represented by the general formula (C ), Which are compounds of ethylene urea, uric acid and glycoluril.
Moreover, the compound of general formula (B) is a saccharin and a phthalimide in the said compound, As a preferable compound, the phthalimide which is a compound of general formula (D) can be mentioned.

(V) The addition amount of the specific cyclic compound is preferably in the range of 0.002 g to 10 g and more preferably in the range of 0.05 g to 5 g in 1 L of the metal polishing slurry used for polishing. A range of 0.1 g to 2 g is particularly preferable. That is, the addition amount of the compound used for suppressing the fluctuation of the polishing rate over time of the polishing liquid is preferably 0.002 g or more in 1 L of the metal polishing liquid from the viewpoint of suppressing the fluctuation of the polishing speed over time. 10 g or less is preferable from the viewpoint of making it difficult to reduce the polishing rate before the polishing.
The specific cyclic compound may be used alone or in combination of two or more.

<(I) Organic acid>
The metal polishing slurry according to the present invention further contains at least one organic acid. The organic acid here is not a metal oxidizing agent, but has an action of promoting oxidation, adjusting pH, and buffering agent.

As the organic acid, water-soluble ones are preferable, and those selected from the following compounds 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 ammonium salts and alkali metals thereof Examples thereof include salts such as salts, ammonium salts, and mixtures thereof.

Amino acids are also preferred as one of the organic acids. The amino acid is preferably water-soluble, and those selected from the following compounds 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.

The addition amount of the organic acid is preferably 0.005 to 0.5 mol, more preferably 0.01 to 0.3 mol, in 1 L of the polishing liquid used for polishing, More preferably, it is 0.3 mol. This range is preferable because it is possible to achieve both high polishing rate and low dishing.
These organic acids can be synthesized according to conventional methods, or commercially available products may be used.

<(II) Passive film forming agent>
The metal polishing liquid of the present invention contains at least one (II) passive film forming agent as a compound that forms a passive film on the metal surface to be polished.
Here, the passivating film forming agent is a heteroaromatic ring compound having a structure different from that of the compounds represented by the general formula (A) and the general formula (B), and an oxidation-resistant film is formed on the surface of the object to be polished. Examples thereof include compounds that can be formed to control the polishing state. Here, the “heteroaromatic ring compound” is a compound having a heterocycle containing one or more heteroatoms. A hetero atom means an atom other than a carbon atom and a hydrogen atom. A heterocycle means a cyclic compound having at least one heteroatom. A heteroatom means only those atoms that form part of a heterocyclic ring system, either external to the ring system, separated from the ring system by at least one non-conjugated single bond, An atom that is part of a further substituent of is not meant.

  The heteroatom is preferably a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, and a boron atom, more preferably a nitrogen atom, a sulfur atom, an oxygen atom, and a selenium atom. And particularly preferably a nitrogen atom, a sulfur atom and an oxygen atom, and most preferably a nitrogen atom and a sulfur atom.

First, the heteroaromatic ring that is the mother nucleus is described.
The number of members of the heterocyclic ring of the heteroaromatic ring compound that can be used in the present invention is not particularly limited, and it may be a monocyclic compound or a polycyclic compound having a condensed ring. The number of members in the case of a single ring is preferably 3 to 8, more preferably 5 to 7, and particularly preferably 5 and 6. The number of rings in the case of having a condensed ring is preferably 2 to 4, more preferably 2 or 3.

Specific examples of these heteroaromatic rings include the following. However, it is not limited to these.
For example, pyrrole ring, thiophene ring, furan ring, pyran ring, thiopyran ring, imidazole ring, pyrazole ring, thiazole ring, isothiazole ring, oxazole ring, isoxazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, pyrrolidine Ring, pyrazolidine ring, imidazolidine ring, isoxazolidine ring, isothiazolidine ring, piperidine ring, piperazine ring, morpholine ring, thiomorpholine ring, chroman ring, thiochroman ring, isochroman ring, isothiochroman ring, indoline ring, isoindoline ring , Indolizine ring, indole ring, indazole ring, purine ring, quinolidine ring, isoquinoline ring, quinoline ring, naphthyridine ring, phthalazine ring, quinoxaline ring, quinazoline ring, cinnoline ring, pteridine ring, acridine ring, pendant Midine ring, phenanthroline ring, carbazole ring, carboline ring, phenazine ring, anti-lysine ring, thiadiazole ring, oxadiazole ring, triazine ring, triazole ring, tetrazole ring, benzimidazole ring, benzoxazole ring, benzothiazole ring, benzothiadiazole A ring, a benzofuroxane ring, a naphthimidazole ring, a benzotriazole ring, a tetraazaindene ring and the like, and more preferably a triazole ring, a tetrazole ring or a benzotriazole ring.

Next, substituents that the heteroaromatic ring may have will be described.
In the present invention, when a specific moiety is referred to as a “group”, the moiety may be unsubstituted or substituted with one or more (up to the maximum possible) substituents. Means good. For example, “alkyl group” means a substituted or unsubstituted alkyl group.

Examples of the substituent that the heteroaromatic ring compound of the passive film forming agent may have include the following. However, it is not limited to these.
For example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched or cyclic alkyl group, and even a polycyclic alkyl group such as a bicycloalkyl group is active. A methine group), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (regardless of the position of substitution), an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a heterocyclic oxycarbonyl group, a carbamoyl group ( Examples of the carbamoyl group having a substituent include an N-hydroxycarbamoyl group, an N-acylcarbamoyl group, an N-sulfonylcarbamoyl group, an N-carbamoylcarbamoyl group, a thiocarbamoyl group, and an N-sulfamoylcarbamoyl group), a carbazoyl group. , Carboxyl group or salt thereof, oxalyl group, oxy Moyl group, cyano group, carbonimidoyl group, formyl group, hydroxy group, alkoxy group (including groups containing repeating ethyleneoxy group or propyleneoxy group units), aryloxy group, heterocyclic oxy group, acyloxy group, (alkoxy group) Or aryloxy) carbonyloxy group, carbamoyloxy group, sulfonyloxy group, amino group, (alkyl, aryl, or heterocyclic) amino group, acylamino group, sulfonamido group, ureido group, thioureido group, N-hydroxyureido group, Imido group, (alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfur Nylureido group, N-acylureido group, N-acylsulfamoylamino group, hydroxyamino group, nitro group, heterocyclic group containing a quaternized nitrogen atom (for example, pyridinio group, imidazolio group, quinolinio group, isoquinolinio group ), Isocyano group, imino group, mercapto group, (alkyl, aryl, or heterocyclic) thio group, (alkyl, aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group , A sulfo group or a salt thereof, a sulfamoyl group (the sulfamoyl group having a substituent is, for example, an N-acylsulfamoyl group or an N-sulfonylsulfamoyl group) or a salt thereof, a phosphino group, a phosphinyl group, a phosphinyl group Examples include oxy group, phosphinylamino group, silyl group It is done.

Here, “active methine group” means a methine group substituted with two electron-attracting groups.
“Electron withdrawing group” means, for example, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group, trifluoromethyl group, cyano group, nitro group, carvone An imidoyl group is meant. Two electron-withdrawing groups may be bonded to each other to form a cyclic structure.
Furthermore, the “salt” means a cation such as an alkali metal, an alkaline earth metal, or a heavy metal, or an organic cation such as an ammonium ion or a phosphonium ion.

  Among these, preferable substituents in the heteroaromatic ring compound include, for example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched or cyclic alkyl group, A polycyclic alkyl group such as an alkyl group or an active methine group may be included), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (regarding the position of substitution), an acyl group, an alkoxycarbonyl group , Aryloxycarbonyl group, heterocyclic oxycarbonyl group, carbamoyl group, N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group , Carbazoyl group, oxalyl group, oxamoyl group A cyano group, a carbonimidoyl group, a formyl group, a hydroxy group, an alkoxy group (including a group containing repeating ethyleneoxy group or propyleneoxy group units), an aryloxy group, a heterocyclic oxy group, an acyloxy group, (alkoxy or aryloxy) ) Carbonyloxy group, carbamoyloxy group, sulfonyloxy group, (alkyl, aryl, or heterocyclic) amino group, acylamino group, sulfonamide group, ureido group, thioureido group, N-hydroxyureido group, imide group, (alkoxy or Aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfonylureido group, N Acylureido group, N-acylsulfamoylamino group, hydroxyamino group, nitro group, heterocyclic group containing a quaternized nitrogen atom (eg, pyridinio group, imidazolio group, quinolinio group, isoquinolinio group), isocyano group, imino group Group, mercapto group, (alkyl, aryl, or heterocyclic) thio group, (alkyl, aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group or a salt thereof Sulfamoyl group, N-acylsulfamoyl group, N-sulfonylsulfamoyl group or a salt thereof, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, silyl group and the like.

  More preferably, for example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched or cyclic alkyl group, and a polycyclic alkyl group such as a bicycloalkyl group). Or an active methine group may be included), an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group (regarding the position of substitution).

In addition, two of the above-mentioned substituents can jointly form a ring.
The ring formed is an aromatic or non-aromatic hydrocarbon ring, or a heteroaromatic ring, which can be further combined to form a polycyclic fused ring. Examples thereof include a benzene ring, Naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, triphenylene ring, naphthacene ring, biphenyl ring, pyrrole ring, furan ring, thiophene ring, imidazole ring, oxazole ring, thiazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring , Indolizine ring, indole ring, benzofuran ring, benzothiophene ring, isobenzofuran ring, quinolidine ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinoxazoline ring, isoquinoline ring, carbazole ring, phenanthridine ring, acridine ring , Phenanthroline ring, Antoren ring, chromene ring, and a xanthene ring, phenoxathiin ring, phenothiazine ring, phenazine ring, and

From the viewpoint of having a high polishing rate among the explanations so far, and suppressing a decrease in the polishing rate over time, and obtaining a polishing liquid excellent in stability over time, in the present invention, benzotriazole and its derivatives, 1, 2,3-triazole and derivatives thereof, 1,2,4-triazole and derivatives thereof, and tetrazole and derivatives thereof are more preferably used.
Specific examples include the following compounds.

  In addition, the following compounds are particularly preferable in the present invention from the viewpoint of having a high polishing rate, suppressing fluctuations in the polishing rate over time of the metal polishing solution, and obtaining a polishing solution having excellent temporal stability. That is, it is a compound of a benzotriazole derivative represented by the following general formula (E).

In general formula (E), R ⁶ represents a methyl group, a carboxyl group, or a sulfo group. n represents an integer of 0 to 2. R ⁷ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms containing a carboxyl group, an alkyl group having 1 to 4 carbon atoms containing a hydroxy group, or a carbon number containing a hydroxy group and an amino group. Represents an alkyl group in the range of 1-6.
R ⁶ is preferably a methyl group. n is preferably 0 or 1. R ⁷ is preferably an alkyl group having 1 to 3 carbon atoms containing a hydroxy group, or an alkyl group having 1 to 5 carbon atoms containing a hydroxy group and an amino group, and N, N-bis (hydroxyethyl) ) An aminomethyl group or a 2,3-dihydroxypropyl group is more preferable.

The total amount of the heteroaromatic ring compound (II) used in the present invention as the passive film forming agent is preferably in the range of 0.0001 to 0.1 mol in 1 L of the metal polishing liquid used for polishing. More preferably, it is the range of 0.0001-0.01 mol, More preferably, it is the range of 0.0005-0.005 mol. This range is preferable because it is possible to achieve both a high polishing rate and low dishing.
A heteroaromatic ring compound may be used individually by 1 type, or may use 2 or more types together.

<(III) Abrasive grains>
The metal polishing slurry of the present invention contains (III) abrasive grains.
Examples of preferable abrasive grains include silica (precipitated silica, fumed silica, colloidal silica, synthetic silica), ceria, alumina, titania, zirconia, germania, manganese oxide, silicon carbide, polystyrene, polyacryl, polyterephthalate, and the like. However, it is more preferable to use colloidal silica.

As addition amount of an abrasive grain, it is preferable that 0.1-50 g of abrasive grain is contained in 1 L of metal polishing liquids at the time of use, More preferably, 1-10 g of abrasive grain is included.
The abrasive grains preferably have an average particle size of 5 to 200 nm, more preferably 10 to 100 nm. An average particle size within this range is preferable because it is possible to achieve both a high polishing rate and low dishing.
Here, the average particle size of the abrasive particles in the present invention represents an average particle size obtained in the particle size distribution obtained from the dynamic light scattering method. For example, LB-500 manufactured by HORIBA, Ltd. is used as a measuring device for obtaining the particle size distribution.

A part of the abrasive grains used may be associated. The degree of association is preferably 3 or less, and preferably 2 or less.
Here, the degree of association means a value (average particle diameter / primary particle diameter) obtained by dividing the average particle diameter formed by aggregation of primary particles by the primary particle diameter. Here, the degree of association of 1 means only monodispersed primary particles.
In addition, 10-100 nm is preferable and the diameter of a primary particle has more preferable 15-50 nm. A primary particle size in this range is preferable because it is possible to achieve both a high polishing rate and low dishing.

<(IV) Oxidizing agent>
The metal-polishing liquid of the present invention preferably contains (IV) an oxidizing agent that is a compound capable of oxidizing the metal to be polished.
Specifically, hydrogen peroxide, peroxide, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, persulfate, dichromium Acid salts, permanganates, ozone water, silver (II) salts, and iron (III) salts are exemplified, and hydrogen peroxide is more preferably used.
The addition amount of the oxidizing agent is preferably in the range of 0.003 mol to 8 mol, more preferably in the range of 0.03 mol to 6 mol, in 1 L of the metal polishing liquid used for polishing. A range of 1 mol to 4 mol is particularly preferable. That is, the addition amount of the oxidizing agent is preferably 0.003 mol or more from the viewpoint of sufficient metal oxidation and ensuring a high CMP rate, and is preferably 8 mol or less from the viewpoint of preventing roughening of the polished surface.

  The metal polishing slurry of the present invention may further contain other components, and examples thereof include surfactants, hydrophilic polymers, alkali agents, buffers, and other additives.

<Surfactant / Hydrophilic polymer>
The metal polishing slurry of the present invention preferably contains a surfactant or a hydrophilic polymer.
Both the surfactant and the hydrophilic polymer have the action of reducing the contact angle of the surface to be polished and the action of promoting uniform polishing.
As the surfactant and the hydrophilic polymer used, those selected from the following groups are suitable.

Examples of the anionic surfactant include carboxylate, sulfonate, sulfate ester salt and phosphate ester salt. Examples of the cationic surfactant include aliphatic amine salt, aliphatic quaternary ammonium salt, benzalkco chloride. Examples thereof include nium salts, benzethonium chloride, pyridinium salts, and imidazolinium salts.
Examples of amphoteric surfactants include carboxybetaine type, aminocarboxylate, imidazolinium betaine, lecithin, and alkylamine oxide.
Nonionic surfactants include ether type, ether ester type, ester type, and nitrogen-containing type.
Moreover, a fluorine-type surfactant etc. are used.

  Furthermore, examples of the hydrophilic polymer include polyglycols such as polyethylene glycol, polysaccharides such as polyvinyl alcohol, polovinyl pyrrolidone, and alginic acid, and carboxylic acid-containing polymers such as polymethacrylic acid.

Of the above, the acid or its ammonium salt is preferably free from contamination by alkali metals, alkaline earth metals, halides and the like.
Among the above exemplified compounds, cyclohexanol, polyacrylic acid ammonium salt, polyvinyl alcohol, succinic acid amide, polo vinyl pyrrolidone, polyethylene glycol, and polyoxyethylene polyoxypropylene block polymer are more preferable.

The weight average molecular weight of these surfactants and hydrophilic polymers is preferably from 500 to 100,000, particularly preferably from 2,000 to 50,000.
The total amount of the surfactant and / or hydrophilic polymer added is preferably 0.001 to 10 g and preferably 0.01 to 5 g in 1 liter of the metal polishing slurry used for polishing. Is more preferably 0.1 to 3 g.

<Alkaline agent / buffer agent>
It is preferable that an alkali agent or a buffering agent is added to the metal polishing liquid of the present invention so as to have a predetermined pH.
Alkaline agents (and buffering agents) include non-metallic alkaline agents such as organic ammonium hydroxides such as ammonium hydroxide and tetramethylammonium hydroxide, alkanolamines such as diethanolamine, triethanolamine and triisopropanolamine, Alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, carbonates such as sodium carbonate, phosphates such as trisodium phosphate, borate, tetraborate, hydroxybenzoate, etc. Can be mentioned.
Particularly preferred alkali agents are ammonium hydroxide, potassium hydroxide, lithium hydroxide and tetramethylammonium hydroxide.

  The addition amount of the alkaline agent (and buffering agent) may be an amount that maintains the pH within a preferable range, and is 0.0001 mol to 1.0 mol in 1 L of the metal polishing slurry used for polishing. It is preferably 0.003 mol to 0.5 mol, and more preferably.

  The pH of the metal polishing liquid when used for polishing is preferably 6.0 to 8.5, more preferably 6.0 to 8.0. Within this range, the metal liquid of the present invention exhibits particularly excellent effects. The pH of the polishing liquid is adjusted to the above preferred range with the alkali agent (buffer agent) and acid agent.

<Chemical mechanical polishing method>
In the chemical mechanical polishing method of the present invention, the metal polishing liquid of the present invention is supplied to the polishing pad on the polishing surface plate, and the polishing surface plate is rotated, whereby the polishing pad is polished on the object to be polished. It is characterized by polishing with relative movement while being in contact with a surface.
Hereinafter, this chemical mechanical polishing method will be described in detail.

(Polishing equipment)
First, an apparatus capable of carrying out the polishing method of the present invention will be described.
As a polishing apparatus applicable to the present invention, a holder for holding an object to be polished (semiconductor substrate or the like) having a surface to be polished and a polishing pad are attached (a motor or the like whose rotation speed can be changed is attached). A general polishing apparatus provided with a polishing surface plate can be used, for example, F-REX300 (Ebara Seisakusho) can be used.

(Polishing pressure)
In the polishing method of the present invention, polishing is preferably performed at a polishing pressure, that is, a contact pressure between the surface to be polished and the polishing pad of 3000 to 25000 Pa, and more preferably 6500 to 18000 Pa.

(Number of rotations of polishing surface plate)
In the polishing method of the present invention, the polishing is preferably performed at a rotation speed of the polishing platen of 50 to 200 rpm, more preferably 60 to 150 rpm.

(Polishing liquid supply method)
In the present invention, the metal polishing liquid is continuously supplied to the polishing pad on the polishing surface plate by a pump or the like while the target metal is polished. Although there is no restriction | limiting in this supply amount, it is preferable that the surface of a polishing pad is always covered with polishing liquid.

  In the polishing method of the present invention, water or an aqueous solution can be added to a concentrated polishing liquid for dilution. As a dilution method, for example, a method of supplying a concentrated polishing liquid to a polishing pad by joining and mixing a pipe for supplying a concentrated polishing liquid and a pipe for supplying water or an aqueous solution together in the middle. Can be mentioned. In this case, mixing is a method in which liquids collide with each other through a narrow passage with pressure applied, a method in which a filling such as a glass tube is filled in the piping, a flow of liquid is separated and separated, and piping is repeated. Conventional methods such as a method of providing blades that rotate with power can be used.

Further, as another dilution method, a pipe for supplying a polishing liquid and a pipe for supplying water or an aqueous solution are provided independently, and a predetermined amount of liquid is supplied from each to the polishing pad, and the polishing pad and the surface to be polished are provided. A method of mixing by relative motion can also be used in the present invention.
Further, a method in which a predetermined amount of concentrated polishing liquid and water or an aqueous solution are mixed in one container, mixed and diluted to a predetermined concentration, and then the mixed liquid is supplied to the polishing pad is also applicable to the present invention. be able to.

  In addition to these methods, a method in which the component to be contained in the polishing liquid is divided into at least two components, and when these are used, water or an aqueous solution is added and diluted to be supplied to the polishing pad is also used in the present invention. be able to. In this case, it is preferable to divide and supply the component containing an oxidizing agent and the component containing the organic acid in the present invention.

  Specifically, the oxidizing agent is preferably one component (A), and the organic acid, additive, surfactant, heterocyclic compound, abrasive grains, and water are preferably one component (B). When using them, the component (A) and the component (B) are diluted with water or an aqueous solution. In this case, three pipes for supplying the component (A), the component (B), and water or an aqueous solution are necessary, and the three pipes are connected to one pipe for supplying the polishing pad, The two pipes may be combined and then another one pipe may be combined and mixed. For example, a component containing a hard-to-dissolve additive is mixed with other components, and the mixing path is lengthened to ensure a dissolution time, and then a polishing liquid is supplied by further coupling a water or aqueous solution pipe. It is also possible.

  Further, the above three pipes may be led to the polishing pad and mixed and supplied by the relative movement of the polishing pad and the surface to be polished. After mixing the three components in one container, the mixed solution is supplied. You may supply to a polishing pad. Further, the metal polishing liquid may be a concentrated liquid, and the diluted water may be separately supplied to the polishing surface.

(Abrasive supply amount)
In the polishing method of the present invention, the supply amount of the polishing liquid onto the polishing surface plate is preferably 50 to 500 ml / min, and more preferably 100 to 300 ml / min.

(Polishing pad)
The polishing pad used in the polishing method of the present invention is not particularly limited, and 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.

  The polishing pad in the present invention may further 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. In addition, the surface contacting the polishing surface may be subjected to processing such as lattice grooves / holes / concentric grooves / helical grooves.

  Next, an object to be polished (substrate, wafer) to be polished in the polishing method of the present invention will be described.

(Wiring metal material)
The object to be polished in the present invention is preferably a substrate (wafer) having wiring made of copper or a copper alloy. As the wiring metal material, a copper alloy containing silver is suitable among the copper alloys. The silver content contained in the copper alloy exhibits an excellent effect at 10% by mass or less, further 1% by mass or less, and the most excellent effect in the copper alloy in the range of 0.00001 to 0.1% by mass. Demonstrate.

(Wiring thickness)
In the DRAM device system, for example, the object to be polished in the present invention preferably has a wiring with a half pitch, preferably 0.15 μm or less, more preferably 0.10 μm or less, and further preferably 0.08 μm or less.
On the other hand, the MPU device system preferably has a wiring of preferably 0.12 μm or less, more preferably 0.09 μm or less, and still more preferably 0.07 μm or less.
The polishing liquid used in the present invention exhibits a particularly excellent effect on the object to be polished having such wiring.

(Barrier metal material)
In the object to be polished in the present invention, a barrier layer for preventing copper diffusion is provided between the copper wiring and the insulating film (including the interlayer insulating film). As the barrier metal material constituting the barrier layer, a low-resistance metal material such as TiN, TiW, Ta, TaN, W, WN or the like is preferable, and Ta or TaN is particularly preferable.

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

(Examples 1-11, Comparative Examples 1-2)
A metal polishing liquid having the composition shown in Table 1 was prepared as follows, and a polishing test and evaluation were performed.

(Preparation of metal polishing liquid)
The following compositions were mixed to prepare each metal polishing liquid shown in Table 1.
Abrasive grains: colloidal silica (primary particle size 20 nm, degree of association 2) 1.0 g / L
Organic acid: N-methylglycine 0.20 mol / L
Passive film forming agent: Compound and addition amount shown in Table 1. Specific cyclic compound: Compound and addition amount shown in Table 1. Oxidizing agent: Hydrogen peroxide 3 g / L
-Preservative: Rocima 560 1.82 g / L
(Rohm & Haas Co., a mixture of 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one)
Pure water was added to make a total volume of 1000 mL, and the pH was adjusted to 7.5 with ammonia water.

(Polishing test)
Polishing was performed under the following conditions, and the polishing rate was evaluated.
・ Polishing equipment: F-REX300 (Ebara Works)
-Polishing object (wafer): Blanket wafer with a diameter of 300 mm with a Cu film having a thickness of 4.0 μm formed on a silicon substrate-Polishing pad: IC1400 XY-K Groove (manufactured by Rodel)
・ Polishing conditions;
Polishing pressure (contact pressure between the surface to be polished and the polishing pad): 17500 Pa
Polishing liquid supply rate: 250 ml / min
Polishing platen rotation speed: 104rpm
Polishing head rotation speed: 85 rpm

(Evaluation methods)
Polishing liquid aging method: The prepared polishing liquid was put in a plastic container and allowed to stand at 23 ° C. for 7 days.
Calculation of polishing rate: For the polishing liquid aged by the above method and the polishing liquid immediately after preparation, each Cu blanket wafer was polished for 60 seconds, and the metal film thickness before and after polishing was applied to 49 equally spaced locations on the wafer surface. Was obtained by converting from the electrical resistance value, and the average value of the values obtained by dividing them by the polishing time was taken as the polishing rate.
Table 1 shows the evaluation results.

  As is apparent from Table 1, Examples 1 to 10 using the metal polishing liquid of the present invention were immediately after the metal polishing liquid was prepared in the chemical mechanical polishing method (the polishing method of the present invention). Even after 7 days from the preparation, a high polishing rate of 700 nm / min or more is obtained, and even if the metal polishing solution is aged, the change in the polishing rate with the lapse of time is kept small. It was found that the metal polishing liquid was excellent in stability over time. On the other hand, Comparative Example 1 and Comparative Example 2 which are not the metal polishing liquid of the present invention show a large change in the polishing rate when the metal polishing liquid is aged. It can be seen that the speed cannot be obtained.

Claims (8)

Contains (I) an organic acid, (II) a passive film forming agent, (III) abrasive grains, (IV) an oxidizing agent, and (V) a compound represented by the following general formula (A) or general formula (B) Polishing liquid for metal.

In general formula (A), R ¹ represents a hydrogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group, and Q represents a linking group that can form a 5-membered ring or a 6-membered ring. .

In general formula (B), R ² represents a hydrogen atom, a hydroxy group, a carboxyl group, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group, and A represents a carbonyl group, a sulfoxide, or a sulfone group. M represents a hydrogen atom or an alkali metal. The metal polishing slurry according to claim 1, wherein the compound represented by the general formula (A) is a compound represented by the following general formula (C).

In general formula (C), R ³ and R ⁴ each independently represent a hydrogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a heterocyclic group, an amino group, or a carboxyl group, which are connected to form a ring. May be formed. The metal polishing slurry according to claim 1, wherein the compound represented by the general formula (B) is a compound represented by the following general formula (D).

In general formula (D), R ⁵ represents a hydrogen atom, a hydroxy group, a carboxyl group, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group, and M represents a hydrogen atom or an alkali metal.   The metal polishing slurry according to any one of claims 1 to 3, wherein the (II) passivating film forming agent is benzotriazole or a derivative thereof.   The metal polishing slurry according to any one of claims 1 to 3, wherein the (II) passivating film forming agent is 1,2,3-triazole and derivatives thereof.   The metal polishing slurry according to any one of claims 1 to 3, wherein the (II) passivating film forming agent is 1,2,4-triazole and derivatives thereof. The metal polishing slurry according to any one of claims 1 to 4, wherein the (II) benzotriazole and a derivative thereof as a passive film forming agent are represented by the following general formula (E).

In general formula (E), R ⁶ represents a methyl group, a carboxyl group, or a sulfo group. n represents an integer of 0 to 2. R ⁷ represents a hydrogen atom, an alkyl group containing a carboxyl group, an alkyl group containing a hydroxy group, or an alkyl group containing both a hydroxy group and an amino group. (1) A step of supplying the metal polishing liquid according to any one of claims 1 to 7 to a polishing pad on a polishing surface plate and rotating the polishing surface plate (2) covering the polishing pad A chemical mechanical polishing method comprising a step of polishing by making a relative movement while contacting with a surface to be polished of a polishing body.