JP2012069785A - Polishing composition and polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing composition which can be used suitably in polishing for forming the interconnections of a semiconductor device, and to provide a polishing method using it.SOLUTION: The polishing composition contains a protective film formation agent which is a compound represented by the following chemical formula (1). In the chemical formula (1), Ris a hydroxyl group or an amino group, and Rto Rare a hydrogen atom, a hydroxyl group, an amino group, an amido group, a nitro group, a methoxy group, an ethoxy group, a halogen group, an alkyl group of 1 to 4C, or a functional group represented by the following chemical formula (2) or (3), independently.

Description

  The present invention relates to a polishing composition used in polishing for forming a wiring of a semiconductor device, for example.

  When forming a wiring of a semiconductor device, generally, a barrier layer and a conductor layer are first formed sequentially on an insulator layer having a trench. Thereafter, at least a portion of the conductor layer positioned outside the trench (outer portion of the conductor layer) and a portion of the barrier layer positioned outside the trench (the outer portion of the barrier layer) are removed by chemical mechanical polishing. The polishing for removing at least the outer portion of the conductor layer and the outer portion of the barrier layer is usually performed in a first polishing step and a second polishing step. In the first polishing step, a part of the outer portion of the conductor layer is removed to expose the upper surface of the barrier layer. In the subsequent second polishing step, at least the remaining portion of the outer portion of the conductor layer and the outer portion of the barrier layer are removed to expose the insulator layer and obtain a flat surface.

  In polishing for forming the wiring of such a semiconductor device, it is common to use a polishing composition containing a polishing accelerator such as an acid and an oxidizing agent, and further containing abrasive grains as necessary. is there. It has also been proposed to use a polishing composition further added with a metal anticorrosive to improve the flatness of the polished object after polishing. For example, Patent Document 1 discloses the use of a polishing composition containing aminoacetic acid and / or amidosulfuric acid, an oxidizing agent, benzotriazole, and water. Patent Document 2 uses a polishing composition containing an anionic surfactant such as polyoxyethylene lauryl ether ammonium sulfate, a protective film forming agent such as benzotriazole, and a nonionic surfactant such as polyoxyethylene alkyl ether. There is a disclosure of that. Patent Document 3 discloses the use of a polishing composition containing an epihalohydrin-modified polyamide.

  By the way, when a wiring of a semiconductor device, particularly a wiring made of copper or a copper alloy is formed by chemical mechanical polishing, an unintended indentation may occur on the side of the formed wiring. This dent on the side of the wiring is considered to be caused mainly by the corrosion of the surface of the portion of the conductor layer located near the boundary with the insulator layer during polishing. Another problem is that the portion of the conductor layer located in the trench that should not be removed is polished and removed, so that the level of the upper surface of the conductor layer is lowered, resulting in dish-shaped dents, that is, dishing. It was. Even when the conventional polishing composition as described above is used, it is difficult to sufficiently prevent both the recesses on the side of the wiring and dishing.

JP-A-8-83780 JP 2008-41781 A JP 2002-110595 A

  Accordingly, an object of the present invention is to provide a polishing composition that can be more suitably used in polishing for forming a wiring of a semiconductor device, and a polishing method using the same.

  In order to achieve the above object, in one embodiment of the present invention, a polishing composition containing a protective film forming agent and a polishing accelerator is provided. The protective film forming agent has the chemical formula (1):

で表される化合物である。化学式（１）において、Ｒ_１はヒドロキシル基またはアミノ基であり、Ｒ_２〜Ｒ_６はそれぞれ独立に、水素原子、ヒドロキシル基、アミノ基、アミド基、ニトロ基、メトキシ基、エトキシ基、ハロゲン基、炭素原子数が１〜４のアルキル基、または以下の化学式（２）もしくは化学式（３）で表される官能基のいずれかである。

It is a compound represented by these. In the chemical formula (1), R ₁ is a hydroxyl group or an amino group, and R _{2 to} R ₆ are each independently a hydrogen atom, a hydroxyl group, an amino group, an amide group, a nitro group, a methoxy group, an ethoxy group, or a halogen group. , An alkyl group having 1 to 4 carbon atoms, or a functional group represented by the following chemical formula (2) or chemical formula (3).

化学式（１）のＲ_２またはＲ_６は、水素原子またはヒドロキシル基であることが好ましい。

R ₂ or R _{6 in} the chemical formula (1) is preferably a hydrogen atom or a hydroxyl group.

  The compound represented by the chemical formula (1) is, for example, benzoylhydrazine, salicylhydrazide, 4-hydroxybenzohydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, benzohydroxamic acid or salicylhydroxamic acid.

The polishing composition according to the above aspect may further contain a metal anticorrosive.
In another aspect of the present invention, there is provided a polishing method for polishing a surface of a polishing object having copper or a copper alloy using the polishing composition according to the above aspect.

  ADVANTAGE OF THE INVENTION According to this invention, the polishing composition which can be used conveniently by the grinding | polishing for forming the wiring of a semiconductor device, and the grinding | polishing method using the same are provided.

Hereinafter, an embodiment of the present invention will be described.
The polishing composition of this embodiment comprises a protective film forming agent and a polishing accelerator, preferably together with at least one of a surfactant, a metal anticorrosive, an oxidizing agent, abrasive grains, and a water-soluble polymer. It is prepared by mixing in a solvent such as Accordingly, the polishing composition contains a protective film forming agent and a polishing accelerator, and preferably further contains at least one of a surfactant, a metal anticorrosive, an oxidizing agent, abrasive grains, and a water-soluble polymer.

  The polishing composition of this embodiment is mainly used in the polishing for forming the wiring of the semiconductor device as described above in the background art section, particularly in the second polishing step. When a semiconductor device wiring, particularly a wiring made of copper or a copper alloy, is formed by chemical mechanical polishing, an unintended indentation may occur on the side of the formed wiring, but the polishing composition of this embodiment is The dents on the side of the wiring can be suppressed. Therefore, this polishing composition is suitably used in applications for forming wiring of semiconductor devices, particularly for applications in which the surface of an object to be polished having copper or copper alloy is polished to form wiring made of copper or copper alloy. can do.

(Protective film forming agent)
The protective film forming agent contained in the polishing composition forms a dent on the side of the wiring formed by polishing using the polishing composition by forming a protective film on the surface of the conductor layer of the object to be polished. And suppressing the occurrence of dishing on the surface of the object to be polished after polishing with the polishing composition. As a protective film forming agent having such a function, chemical formula (1):

で表される化合物が使用される。化学式（１）において、Ｒ_１はヒドロキシル基またはアミノ基であり、ヒドロキシル基であることが好ましい。Ｒ_２〜Ｒ_６はそれぞれ独立に、水素原子、ヒドロキシル基、アミノ基、アミド基、ニトロ基、メトキシ基、エトキシ基、ハロゲン基、炭素原子数が１〜４のアルキル基、または以下の化学式（２）もしくは化学式（３）で表される官能基のいずれかである。そのうちＲ_２またはＲ_６は、水素原子、ヒドロキシル基またはアミノ基のいずれかであることが好ましく、より好ましくは水素原子またはヒドロキシ基、さらに好ましくはヒドロキシ基である。

The compound represented by is used. In the chemical formula (1), R ₁ is a hydroxyl group or an amino group, and preferably a hydroxyl group. R _{2 to} R ₆ are each independently a hydrogen atom, hydroxyl group, amino group, amide group, nitro group, methoxy group, ethoxy group, halogen group, alkyl group having 1 to 4 carbon atoms, or the following chemical formula ( 2) or a functional group represented by the chemical formula (3). Of these, R ₂ or R ₆ is preferably a hydrogen atom, a hydroxyl group or an amino group, more preferably a hydrogen atom or a hydroxy group, and still more preferably a hydroxy group.

化学式（１）で表される化合物の具体例としては、例えば、ベンゾイルヒドラジン、２−アミノベンゾイルヒドラジド、４−アミノベンゾヒドラジド、３−メトキシベンゾヒドラジド、４−メトキシベンゾヒドラジド、４−tert−ブチルベンゾヒドラジド、４−ブロモベンゾヒドラジド、２−クロロベンゾヒドラジド、４−クロロベンゾヒドラジド、２−フルオロベンゾヒドラジド、４−フルオロベンゾヒドラジド、サリチルヒドラジド、４−ヒドロキシベンゾヒドラジド、３，４−ジヒドロキシベンゾヒドラジド、３，４−ジアミノベンゾヒドラジド、２−ニトロベンズヒドラジド、３−ニトロベンズヒドラジド、４−ニトロベンズヒドラジド、イソフタル酸ジヒドラジド、テレフタル酸ジヒドラジド、ベンゾヒドロキサム酸、サリチルヒドロキサム酸、および４−ヒドロキシベンゾヒドロキサム酸がある。中でもベンゾイルヒドラジン、サリチルヒドラジド、４−ヒドロキシベンゾヒドラジド、イソフタル酸ジヒドラジド、テレフタル酸ジヒドラジド、ベンゾヒドロキサム酸およびサリチルヒドロキサム酸が好ましく、特に好ましいのはサリチルヒドラジド、イソフタル酸ジヒドラジド、テレフタル酸ジヒドラジド、ベンゾヒドロキサム酸およびサリチルヒドロキサム酸であり、最も好ましいのはベンゾヒドロキサム酸およびサリチルヒドロキサム酸である。これらの化合物は、ナトリウム塩やカリウム塩など金属塩の形態であってもよい。

Specific examples of the compound represented by the chemical formula (1) include, for example, benzoyl hydrazine, 2-aminobenzoyl hydrazide, 4-aminobenzohydrazide, 3-methoxybenzohydrazide, 4-methoxybenzohydrazide, 4-tert-butylbenzo Hydrazide, 4-bromobenzohydrazide, 2-chlorobenzohydrazide, 4-chlorobenzohydrazide, 2-fluorobenzohydrazide, 4-fluorobenzohydrazide, salicylhydrazide, 4-hydroxybenzohydrazide, 3,4-dihydroxybenzohydrazide, 3 , 4-Diaminobenzohydrazide, 2-nitrobenzhydrazide, 3-nitrobenzhydrazide, 4-nitrobenzhydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, benzohydroxamic acid, salicylhydride There are loxamic acid and 4-hydroxybenzohydroxamic acid. Among them, benzoylhydrazine, salicylhydrazide, 4-hydroxybenzohydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, benzohydroxamic acid and salicylhydroxamic acid are preferable, and particularly preferable are salicylhydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, benzohydroxamic acid and Salicylhydroxamic acid, most preferred are benzohydroxamic acid and salicylhydroxamic acid. These compounds may be in the form of metal salts such as sodium salts and potassium salts.

The compound represented by the chemical formula (1) has a hydroxamic acid group (—C (═O) —NH—OH) or a hydrazide group (—C (═O) —NH—NH ₂ ), and a conductor layer. Forms strong complexes with other metals, especially copper. The formed complex exhibits strong poor solubility. Therefore, the compound represented by the chemical formula (1) is considered to be able to reliably form a protective film on the surface of the conductor layer of the object to be polished, including the portion of the conductor layer located near the boundary with the insulator layer. It is done. As a result, the surface of the portion of the conductor layer located in the vicinity of the boundary with the insulator layer is less likely to be corroded during polishing, so that the occurrence of dents on the wiring side and the occurrence of dishing are suppressed.

  The content of the protective film forming agent in the polishing composition is appropriately set according to the amount of transition metal ions contained in the polishing composition, but generally speaking, 0.001 g / L or more is preferable, more preferably 0.01 g / L or more, and still more preferably 0.05 g / L or more. As the content of the protective film-forming agent increases, the object to be polished after polishing using the polishing composition is less likely to cause dents on the sides of the wiring formed by polishing using the polishing composition. There is an advantage that dishing hardly occurs on the surface of the object.

  The content of the protective film forming agent in the polishing composition is also preferably 3 g / L or less, more preferably 1 g / L or less, and still more preferably 0.5 g / L or less. As the content of the protective film forming agent decreases, the material cost of the polishing composition can be reduced, and the polishing rate by the polishing composition is advantageously improved.

(Polishing accelerator)
The polishing accelerator contained in the polishing composition has an action of chemically etching the surface of the object to be polished, and functions to improve the polishing rate of the polishing composition.

Usable polishing accelerators are, for example, inorganic acids, organic acids, amino acids and chelating agents.
Specific examples of the inorganic acid include sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid and phosphoric acid.

  Specific examples of the organic acid include, for example, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid Maleic acid, phthalic acid, malic acid, tartaric acid, citric acid and lactic acid. Organic sulfuric acids such as methanesulfonic acid, ethanesulfonic acid and isethionic acid can also be used.

  A salt such as an ammonium salt or an alkali metal salt of an inorganic acid or an organic acid may be used instead of or in combination with the inorganic acid or the organic acid. In the case of a combination of a weak acid and a strong base, a strong acid and a weak base, or a combination of a weak acid and a weak base, a pH buffering action can be expected.

  Specific examples of amino acids include, for example, glycine, α-alanine, β-alanine, N-methylglycine, N, N-dimethylglycine, 2-aminobutyric acid, norvaline, valine, leucine, norleucine, isoleucine, phenylalanine, proline, Sarcosine, ornithine, lysine, taurine, serine, threonine, homoserine, tyrosine, bicine, tricine, 3,5-diiodo-tyrosine, β- (3,4-dihydroxyphenyl) -alanine, thyroxine, 4-hydroxy-proline, cysteine , Methionine, ethionine, lanthionine, cystathionine, cystine, cysteic acid, aspartic acid, glutamic acid, S- (carboxymethyl) -cysteine, 4-aminobutyric acid, asparagine, glutamine, azaserine, arginine, canavani , Citrulline, .delta.-hydroxy - lysine, creatine, histidine, 1-methyl - histidine, 3-methyl - include histidine and tryptophan. Among them, glycine, N-methylglycine, N, N-dimethylglycine, α-alanine, β-alanine, bicine and tricine are preferable, and glycine is particularly preferable.

  Specific examples of the chelating agent include, for example, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, N, N, N-trimethylenephosphonic acid, ethylenediamine-N, N, N ′, N′-tetramethylenesulfonic acid, Transcyclohexanediaminetetraacetic acid, 1,2-diaminopropanetetraacetic acid, glycol etherdiaminetetraacetic acid, ethylenediamine orthohydroxyphenylacetic acid, ethylenediamine disuccinic acid (SS form), N- (2-carboxylateethyl) -L-aspartic acid , Β-alanine diacetate, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, N, N′-bis (2-hydroxybenzyl) ethylenediamine-N, N′— Diacetic acid and 1,2-dihydroxybenzene Zen-4,6-disulfonic acid and the like.

  The content of the polishing accelerator in the polishing composition is preferably 0.01 g / L or more, more preferably 0.1 g / L or more, and further preferably 1 g / L or more. As the content of the polishing accelerator increases, there is an advantage that the polishing rate by the polishing composition is improved.

  The content of the polishing accelerator in the polishing composition is also preferably 50 g / L or less, more preferably 30 g / L or less, and still more preferably 15 g / L or less. As the content of the polishing accelerator decreases, there is an advantage that excessive etching of the surface of the object to be polished by the polishing accelerator is less likely to occur.

(Surfactant)
When a surfactant is added to the polishing composition, dents are less likely to be formed on the sides of the wiring formed by polishing using the polishing composition, and polishing is performed using the polishing composition. This is advantageous in that dishing is less likely to occur on the surface of the polished object.

  The surfactant used may be any of an anionic surfactant, a cationic surfactant, an amphoteric surfactant and a nonionic surfactant, and among them, an anionic surfactant and Nonionic surfactants are preferred. A plurality of types of surfactants may be used in combination, and it is particularly preferable to use a combination of an anionic surfactant and a nonionic surfactant.

  Specific examples of the anionic surfactant include, for example, polyoxyethylene alkyl ether acetic acid, polyoxyethylene alkyl ether sulfuric acid, alkyl ether sulfuric acid, polyoxyethylene alkyl sulfuric acid ester, alkyl sulfuric acid ester, polyoxyethylene alkyl sulfuric acid, alkyl Examples include sulfuric acid, alkylbenzene sulfonic acid, alkyl phosphoric acid ester, polyoxyethylene alkyl phosphoric acid ester, polyoxyethylene sulfosuccinic acid, alkyl sulfosuccinic acid, alkyl naphthalene sulfonic acid, alkyl diphenyl ether disulfonic acid, and salts thereof. Of these, polyoxyethylene alkyl ether acetic acid, polyoxyethylene alkyl ether sulfate, alkyl ether sulfate and alkylbenzene sulfonate are preferred. Since these preferable anionic surfactants have a high chemical or physical adsorption force to the surface of the object to be polished, a stronger protective film is formed on the surface of the object to be polished. This is advantageous in improving the flatness of the surface of the object to be polished after polishing with the polishing composition.

  Specific examples of the cationic surfactant include, for example, alkyl trimethyl ammonium salt, alkyl dimethyl ammonium salt, alkyl benzyl dimethyl ammonium salt, and alkyl amine salt.

Specific examples of amphoteric surfactants include alkyl betaines and alkyl amine oxides.
Specific examples of nonionic surfactants include, for example, polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ether, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkyl amines, and alkyl alkanols. Amides are mentioned. Of these, polyoxyalkylene alkyl ether is preferred. Since polyoxyalkylene alkyl ether has high chemical or physical adsorption force to the surface of the polishing object, it forms a stronger protective film on the surface of the polishing object. This is advantageous in improving the flatness of the surface of the object to be polished after polishing with the polishing composition.

  The content of the surfactant in the polishing composition is preferably 0.001 g / L or more, more preferably 0.005 g / L or more, and still more preferably 0.01 g / L or more. As the content of the surfactant increases, there is an advantage that the flatness of the surface of the object to be polished after polishing with the polishing composition is improved.

  The content of the surfactant in the polishing composition is also preferably 10 g / L or less, more preferably 5 g / L or less, and further preferably 1 g / L or less. As the surfactant content decreases, the polishing rate of the polishing composition is advantageously improved.

(Metal anticorrosive)
When a metal anticorrosive is added to the polishing composition, dents are less likely to be formed on the side of the wiring formed by polishing using the polishing composition, as in the case of adding a surfactant. In addition, there is an advantage that dishing is less likely to occur on the surface of the object to be polished after polishing with the polishing composition. Further, when the polishing composition contains an oxidizing agent, the metal anticorrosive agent relaxes the oxidation of the surface of the object to be polished by the oxidizing agent, and also oxidizes the metal on the surface of the object to be polished by the oxidizing agent. It reacts with the resulting metal ions to form an insoluble complex. The function of this metal anticorrosive improves the flatness of the surface of the object to be polished after polishing with the polishing composition.

  Although the kind of metal anticorrosive used is not particularly limited, it is preferably a heterocyclic compound. The number of heterocyclic rings in the heterocyclic compound is not particularly limited. The heterocyclic compound may be a monocyclic compound or a polycyclic compound having a condensed ring.

  Specific examples of heterocyclic compounds that can be used as metal anticorrosives include, for example, pyrrole compounds, pyrazole compounds, imidazole compounds, triazole compounds, tetrazole compounds, pyridine compounds, pyrazine compounds, pyridazine compounds, pyridine compounds, indolizine compounds, indoles. Compound, isoindole compound, indazole compound, purine compound, quinolidine compound, quinoline compound, isoquinoline compound, naphthyridine compound, phthalazine compound, quinoxaline compound, quinazoline compound, cinnoline compound, buteridine compound, thiazole compound, isothiazole compound, oxazole compound, iso Examples thereof include nitrogen-containing heterocyclic compounds such as oxazole compounds and furazane compounds.

Specific examples of the pyrazole compound include 1H-pyrazole, 4-nitro-3-pyrazole carboxylic acid, and 3,5-pyrazole carboxylic acid.
Specific examples of the imidazole compound include, for example, imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1,2-dimethylpyrazole, 2-ethyl-4-methylimidazole, 2-isopropylimidazole, and benzimidazole. 5,6-dimethylbenzimidazole, 2-aminobenzimidazole, 2-chlorobenzimidazole and 2-methylbenzimidazole.

  Specific examples of the triazole compound include, for example, 1,2,3-triazole, 1,2,4-triazole, 1-methyl-1,2,4-triazole, methyl-1H-1,2,4-triazole- 3-carboxylate, 1,2,4-triazole-3-carboxylic acid, methyl 1,2,4-triazole-3-carboxylate, 1H-1,2,4-triazole-3-thiol, 3,5- Diamino-1H-1,2,4-triazole, 3-amino-1,2,4-triazole-5-thiol, 3-amino-1H-1,2,4-triazole, 3-amino-5-benzyl- 4H-1,2,4-triazole, 3-amino-5-methyl-4H-1,2,4-triazole, 3-nitro-1,2,4-triazole, 3-bromo-5-nitro-1, 2,4- Riazole, 4- (1,2,4-triazol-1-yl) phenol, 4-amino-1,2,4-triazole, 4-amino-3,5-dipropyl-4H-1,2,4-triazole 4-amino-3,5-dimethyl-4H-1,2,4-triazole, 4-amino-3,5-dipeptyl-4H-1,2,4-triazole, 5-methyl-1,2,4 -Triazole-3,4-diamine, 1H-benzotriazole, 1-hydroxybenzotriazole, 1-aminobenzotriazole, 1-carboxybenzotriazole, 5-chloro-1H-benzotriazole, 5-nitro-1H-benzotriazole, 5-carboxy-1H-benzotriazole, 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H-benzotri Sol, 1- (1 ″, 2′-dicarboxyethyl) benzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] benzotriazole, 1- [N, N-bis (hydroxyethyl) amino Methyl] -5-methylbenzotriazole, and 1- [N, N-bis (hydroxyethyl) aminomethyl] -4-methylbenzotriazole.

Specific examples of the tetrazole compound include 1H-tetrazole, 5-methyltetrazole, 5-aminotetrazole, and 5-phenyltetrazole.
Specific examples of indole compounds include 1H-indole, 1-methyl-1H-indole, 2-methyl-1H-indole, 3-methyl-1H-indole, 4-methyl-1H-indole, 5-methyl- 1H-indole, 6-methyl-1H-indole, and 7-methyl-1H-indole.

Specific examples of the indazole compound include 1H-indazole and 5-amino-1H-indazole.
Among them, preferred heterocyclic compounds are compounds having a triazole skeleton, especially 1H-benzotriazole, 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H-benzotriazole, 1- [N, N-bis (hydroxy Ethyl) aminomethyl] -5-methylbenzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] -4-methylbenzotriazole, 1,2,3-triazole, and 1,2,4-triazole Is particularly preferred. Since these heterocyclic compounds have high chemical or physical adsorptive power to the surface of the object to be polished, a stronger protective film is formed on the surface of the object to be polished. This is advantageous in improving the flatness of the surface of the object to be polished after polishing with the polishing composition.

  The content of the metal anticorrosive in the polishing composition is preferably 0.001 g / L or more, more preferably 0.005 g / L or more, and still more preferably 0.01 g / L or more. As the content of the metal anticorrosive increases, there is an advantage that the flatness of the surface of the object to be polished after polishing with the polishing composition is improved.

  The content of the metal anticorrosive in the polishing composition is also preferably 10 g / L or less, more preferably 5 g / L or less, and further preferably 1 g / L or less. As the content of the metal anticorrosive decreases, there is an advantage that the polishing rate by the polishing composition is improved.

(Oxidant)
The oxidizing agent has an action of oxidizing the surface of the object to be polished, and when an oxidizing agent is added to the polishing composition, the polishing rate by the polishing composition is advantageously improved.

  An oxidizing agent that can be used is, for example, a peroxide. Specific examples of the peroxide include, for example, hydrogen peroxide, peracetic acid, percarbonate, urea peroxide and perchloric acid, and persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate. Of these, persulfate and hydrogen peroxide are preferable, and hydrogen peroxide is particularly preferable.

  The content of the oxidizing agent in the polishing composition is preferably 0.1 g / L or more, more preferably 1 g / L or more, and further preferably 3 g / L or more. As the content of the oxidizing agent increases, the polishing rate by the polishing composition is advantageously improved.

  The content of the oxidizing agent in the polishing composition is also preferably 200 g / L or less, more preferably 100 g / L or less, and still more preferably 40 g / L or less. As the content of the oxidizing agent decreases, the material cost of the polishing composition can be reduced, and in addition, it is possible to reduce the load of processing the polishing composition after polishing, that is, waste liquid processing. is there. In addition, there is an advantage that excessive oxidation of the surface of the object to be polished by the oxidizing agent hardly occurs.

(Abrasive grains)
Abrasive grains have the effect of mechanically polishing an object to be polished, and when abrasive grains are added to the polishing composition, the polishing rate by the polishing composition is advantageously improved.

  The abrasive used may be any of inorganic particles, organic particles, and organic-inorganic composite particles. Specific examples of the inorganic particles include particles made of a metal oxide such as silica, alumina, ceria, titania, and silicon nitride particles, silicon carbide particles, and boron nitride particles. Of these, silica is preferable, and colloidal silica is particularly preferable. Specific examples of the organic particles include polymethyl methacrylate (PMMA) particles.

  The average primary particle size of the abrasive grains used is preferably 5 nm or more, more preferably 7 nm or more, and even more preferably 10 nm or more. As the average primary particle diameter of the abrasive grains becomes larger, there is an advantage that the polishing rate by the polishing composition is improved.

  The average primary particle diameter of the abrasive grains used is also preferably 100 nm or less, more preferably 60 nm or less, and still more preferably 40 nm or less. As the average primary particle diameter of the abrasive grains decreases, there is an advantage that dishing is less likely to occur on the surface of the object to be polished after polishing with the polishing composition. In addition, the value of the average primary particle diameter of an abrasive grain is calculated based on the specific surface area of the abrasive grain measured by BET method, for example.

  The content of abrasive grains in the polishing composition is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, and still more preferably 0.05% by mass or more. There is an advantage that the polishing rate by the polishing composition increases as the content of the abrasive grains increases.

  The content of abrasive grains in the polishing composition is also preferably 5% by mass or less, more preferably 1% by mass or less, and still more preferably 0.5% by mass or less. As the content of the abrasive grains decreases, the material cost of the polishing composition can be reduced, and in addition, it is advantageous that dishing is less likely to occur on the surface of the object to be polished after polishing with the polishing composition. is there.

(Water-soluble polymer)
When a water-soluble polymer is added to the polishing composition, it is possible to control the polishing rate by the polishing composition by adsorbing the water-soluble polymer on the surface of the abrasive grains or the surface of the object to be polished. In addition, there is an advantage that insoluble components generated during polishing can be stabilized in the polishing composition.

  Water-soluble polymers that can be used include, for example, polysaccharides such as alginic acid, pectinic acid, carboxymethylcellulose, curdlan and pullulan; polycarboxylic acids and salts thereof; vinyl-based polymers such as polyvinyl alcohol, polyvinylpyrrolidone and polyacrolein; And polyglycerin esters; polyalkyleneimines such as polyethyleneimine and polypropyleneimine; polyacrylamides; polyamide polyamine condensates; and dicyandiamide condensates. Among them, carboxymethylcellulose, pullulan, polycarboxylic acid and salts thereof, polyvinyl alcohol, polyvinylpyrrolidone, polyethyleneimine, polyacrylamide, polyamide polyamine condensate and dicyandiamide condensate are preferable, and pullulan, polyvinyl alcohol, polyamide polyamine condensate and Dicyandiamide condensate.

(PH of polishing composition)
The polishing composition preferably has a pH of 3 or more, more preferably 5 or more. As the pH increases, there is an advantage that excessive etching of the surface of the object to be polished by the polishing composition is less likely to occur.

  The pH of the polishing composition is also preferably 9 or less, more preferably 8 or less. As the pH decreases, there is an advantage that a dent is less likely to be formed on the side of the wiring formed by polishing using the polishing composition.

(Advantages of this embodiment)
According to the present embodiment, the following advantages can be obtained.
The polishing composition of the present embodiment contains a protective film forming agent that is a compound represented by the chemical formula (1). Therefore, the function of the protective film forming agent can suppress the formation of dents on the side of the wiring formed by polishing using the polishing composition, and after polishing using the polishing composition. It is possible to suppress dishing from occurring on the surface of the object to be polished. Therefore, the polishing composition of the present embodiment is used for forming wiring of a semiconductor device, in particular, for forming a wiring made of copper or a copper alloy by polishing the surface of a polishing object having copper or a copper alloy. It can be preferably used.

(Modification)
The embodiment may be modified as follows.
-The polishing composition of the said embodiment may further contain well-known additives, such as antiseptic | preservative and a fungicide, as needed. Specific examples of the antiseptic and fungicide include, for example, isothiazoline-based preservatives such as 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, and paraoxybenzoic acid. Examples include acid esters and phenoxyethanol.

The polishing composition of the above embodiment may be a one-component type or a multi-component type including a two-component type.
-The polishing composition of the said embodiment may be prepared by diluting the undiluted | stock solution of polishing composition 10 times or more using diluents, such as water.

  -The polishing composition of the said embodiment may be used for uses other than grinding | polishing for forming the wiring of a semiconductor device.

Next, examples and comparative examples of the present invention will be described.
A polishing composition of Examples 1 to 27 was prepared by mixing a protective film forming agent, a polishing accelerator, a surfactant, an oxidizing agent, and abrasive grains with water, and further mixing a metal anticorrosive as necessary. did. Polishing compositions of Comparative Examples 1 to 11 were prepared by mixing a compound in place of the protective film forming agent, a polishing accelerator, a surfactant, an oxidizing agent, abrasive grains, and a metal anticorrosive with water. Table 1 shows details of the protective film forming agent in the polishing composition of each example, or an alternative compound and a metal anticorrosive. Although not shown in Table 1, each of the polishing compositions of Examples 1 to 27 and Comparative Examples 1 to 11 has 10 g / L of glycine as a polishing accelerator and 0. 0 as a surfactant. 1 g / L ammonium lauryl ether sulfate and 0.5 g / L polyoxyethylene alkyl ether, 15 g / L hydrogen peroxide as an oxidant, and 0.1% by weight colloidal silica (average primary particles as abrasive grains) 30 nm in diameter). Moreover, all of these polishing compositions are adjusted to pH 6.5 using potassium hydroxide or nitric acid. Table 2 shows the structural formulas of the respective compounds described in the “protective film forming agent or a compound substituted therefor” column, the “first metal anticorrosive agent” column, and the “second metal anticorrosive agent” column in Table 1.

<Indentation on the side of wiring>
Using the polishing composition of each example, the copper film thickness (ATDF754 mask, copper film thickness before polishing 700 nm, trench depth 300 nm) on the surface of the copper pattern wafer was measured under the first polishing conditions shown in Table 3. Polished to 250 nm. Thereafter, the surface of the polished copper pattern wafer was polished using the same polishing composition until the barrier film was exposed under the second polishing conditions described in Table 4. The surface of the copper pattern wafer after the two-step polishing is observed using a review SEM RS-4000 (manufactured by Hitachi High-Technologies Corporation), and a 0.18 μm wide wiring and a 0.18 μm wide insulation. In the region where the films were alternately arranged and the region where the 100 μm wide wiring and the 100 μm wide insulating film were alternately arranged, the presence or absence of a dent on the side of the wiring was confirmed. And, when no dent on the side of the wiring is confirmed in any region, ◎ (excellent), and when a dent on the side of the wiring having a width of less than 10 nm is confirmed in either region, ◯ (good), △ (possible) when a dent on the side of the wiring with a width of 10 nm or more and less than 50 nm is confirmed in any one region, and × (defect) when a dent with a width of 50 nm or more is confirmed in at least one region ). Δ (Yes) or higher is a practical level. The evaluation results are shown in the “Dents on the side of wiring” column in Table 1.

<Polishing speed>
First polishing when the surface of the copper blanket wafer was polished for 60 seconds under the first polishing conditions shown in Table 3 and the second polishing conditions shown in Table 4 using the polishing composition of each example The polishing rate under each of the conditions and the second polishing conditions is shown in the “Polishing rate” column of Table 1. The value of the polishing rate was determined by dividing the difference in thickness of the copper blanket wafer before and after polishing measured by using a sheet resistance measuring instrument VR-120 / 08SD (manufactured by Hitachi Kokusai Electric) by the polishing time. Needless to say, a larger polishing rate is preferable, but it is a practical level if it is 400 nm / min or more in the case of the first polishing condition and 200 nm / min or more in the case of the second polishing condition.

<Dishing>
Using the polishing composition of each example, the copper film thickness (ATDF754 mask, copper film thickness before polishing 700 nm, trench depth 300 nm) on the surface of the copper pattern wafer was measured under the first polishing conditions shown in Table 3. Polished to 250 nm. Thereafter, the polished copper pattern wafer surface was polished using the same polishing composition until the barrier film was exposed under the second polishing conditions shown in Table 4. In the region where 100 μm width wiring and 100 μm width insulating film are alternately arranged in the copper pattern wafer after the two-step polishing is performed, and in the region where 9 μm width wiring and 1 μm width insulating film are alternately arranged, The dishing amount (dishing depth) was measured using Wide Area AFM WA-1300 (manufactured by Hitachi Construction Machinery Finetech Co., Ltd.). The measurement results are shown in the “Dishing” column of Table 1. If the measured dishing value is 100 nm or less, it is a practical level.

表１に示すように、実施例１〜２７の研磨用組成物を使用した場合にはいずれも、配線脇の凹みの評価は△（可）以上であった。また、研磨速度については、第１の研磨条件の場合で４００ｎｍ／分以上、第２の研磨条件の場合で２００ｎｍ／分以上という良好な値が得られ、ディッシングについても１００ｎｍ以下という良好な値が得られた。

As shown in Table 1, in all cases where the polishing compositions of Examples 1 to 27 were used, the evaluation of the dents on the side of the wiring was Δ (good) or higher. As for the polishing rate, good values of 400 nm / min or more in the case of the first polishing condition, 200 nm / min or more in the case of the second polishing condition, and a good value of 100 nm or less for dishing are obtained. Obtained.

On the other hand, when the polishing compositions of Comparative Examples 1 to 11 were used, the result of at least one of the evaluation of the dent on the wiring side and the measured value of dishing was not good.
When comparing the evaluation of the dents on the wiring side when the polishing compositions of Examples 6, 14, 20, 22, 24, 26, and 27 were used, salicyl was more effective than benzohydroxamic acid, benzoylhydrazine, and 4-hydroxybenzohydrazide. It was found that hydrazide, salicylhydroxamic acid, isophthalic acid dihydrazide and terephthalic acid hydrazide were more effective in suppressing the formation of dents on the side of the wiring. Comparing the measured values of dishing when the polishing compositions of Examples 6, 14, 20, and 22 were used, salicyl hydrazide and salicyl hydroxamic acid suppressed the occurrence of dishing compared to isophthalic acid dihydrazide and terephthalic acid hydrazide. It turns out that the effect to do is high. Comparing the evaluation of the dents on the wiring side when the polishing compositions of Examples 2, 6, 10, 14, 19 to 26 were used, by using 1,2,4-triazole in combination with a protective film forming agent, It was found that the dents on the side of the wiring can be further suppressed.

Claims (5)

A polishing composition comprising a protective film forming agent and a polishing accelerator, wherein the protective film forming agent has the chemical formula (1):

In the chemical formula (1), R ₁ is a hydroxyl group or an amino group, and R _{2 to} R ₆ are each independently a hydrogen atom, a hydroxyl group, an amino group, an amide group, a nitro group, For polishing, which is any one of a methoxy group, an ethoxy group, a halogen group, an alkyl group having 1 to 4 carbon atoms, or a functional group represented by the following chemical formula (2) or chemical formula (3) Composition.

The polishing composition according to claim 1, wherein R ₂ or R _{6 in} the chemical formula (1) is a hydrogen atom or a hydroxyl group.   The compound represented by the chemical formula (1) is any one of benzoylhydrazine, salicylhydrazide, 4-hydroxybenzohydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, benzohydroxamic acid or salicylhydroxamic acid. Polishing composition.   The polishing composition according to any one of claims 1 to 3, further comprising a metal anticorrosive.   The grinding | polishing method which grind | polishes the surface of the grinding | polishing target object which has copper or a copper alloy using the polishing composition as described in any one of Claims 1-4.