JP2007227758A - Polishing solution for metal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing solution for metal that has a fast polishing speed and enables an LSI circuit to be manufactured, which has little dishing and gets its planarity improved through improving a copper/tantalum selectivity during polishing. <P>SOLUTION: This is a polishing solution for metal used for chemical-mechanical planarization of a semiconductor device, wherein the solution contains one kind of a tetrazole derivative represented by a general formula (I)(where R<SP>a</SP>denotes at least one substitute group selected from groups such as a sulfo group, an amino group, a sulfono group, a carbamoyl group, a carvone-amide group, a sulfamoyl group, and a sulfonamide group) or by a general formula (II), where R<SP>b</SP>denotes at least one substitute selected from groups such as a hydroxy group, a carboxy group, a sulfo group, an amino group, a phosphono group, a carbamoyl group, a carvone-amide group, a sulfamoyl group, an a sulfonamide group, and L<SP>b</SP>denotes a bivalent linkage group. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to manufacturing of semiconductor devices, and more particularly to a method for manufacturing an organic material for metal polishing in a wiring process of a semiconductor device and a metal polishing liquid using the same.

In the development of a semiconductor device typified by a semiconductor integrated circuit (hereinafter referred to as LSI), high density and high integration by miniaturization and lamination of wiring are required for high integration and high speed. As a technique for this purpose, chemical mechanical polishing (Chemical Mechanical Polishing) that polishes an insulating thin film (SiO ₂ or the like) or a metal thin film used for wiring, and smoothes the substrate or removes an excess metal thin film during wiring formation. Various techniques such as Polishing (hereinafter referred to as CMP) have been used.
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, In a state where pressure (polishing pressure) is applied, both the polishing platen and the base are rotated, and the surface of the base is flattened by the generated mechanical friction.
A metal polishing solution used in CMP generally contains abrasive grains (eg, alumina, silica) and an oxidizing agent (eg, hydrogen peroxide, persulfuric acid). The metal surface is oxidized by the oxidizing agent, and the oxidation is performed. It is considered that the film is polished by removing the film with abrasive grains.

However, when CMP is performed using a metal polishing liquid containing such solid abrasive grains, scratches (scratches), a phenomenon in which the entire polished surface is polished more than necessary (thinning), and the polished metal surface is flat In addition, a phenomenon in which only the center is polished deeper to form a dish-like depression (dishing), an insulator between metal wirings is polished more than necessary, and a plurality of wiring metal surface surfaces form dish-shaped recesses. A phenomenon (erosion) may occur.
In order to solve the problems in such conventional solid abrasive grains, a metal polishing liquid which does not contain abrasive grains and is composed of hydrogen peroxide / malic acid / benzotriazole / ammonium polyacrylate and water is disclosed. (For example, refer to Patent Document 1). According to this method, although the metal film on the convex portion of the semiconductor substrate is selectively CMPed and the metal film is left in the concave portion to obtain a desired conductor pattern, it is much more mechanical than the conventional solid abrasive grains. Since CMP proceeds by friction with a soft polishing pad, it is difficult to obtain a sufficient polishing rate.

  On the other hand, an LSI using copper having low wiring resistance has been developed as a metal for wiring in place of conventional general-purpose tungsten or aluminum as a metal for wiring. Along with the miniaturization of wiring aiming at higher density, it is necessary to improve the conductivity and electronic migration resistance of the copper wiring, and accordingly, use a copper alloy in which a small amount of a third component such as silver is added to high purity copper. It has also been proposed. At the same time, there is a need for high-speed metal polishing means that can exhibit high productivity without contaminating these high-definition and high-purity materials.

Recently, in order to improve productivity, the diameter of a wafer at the time of manufacturing an LSI has been increased. Currently, a diameter of 200 mm or more is widely used, and manufacture with a size of 300 mm or more has also started. With such an increase in size, the difference in polishing rate between the wafer center and the periphery has increased, and the demand for improvement in in-plane uniformity has increased.
As a chemical polishing method having no mechanical polishing means for copper and a copper alloy, a chemical polishing method using only a dissolving action is also known (see, for example, Patent Document 2). However, as compared with CMP in which the metal film of the convex portion is selectively chemically and mechanically polished, problems due to the occurrence of dishing and the like are likely to occur, and ensuring flatness is an issue.
In addition, for the purpose of flattening the step of the polishing surface, an aqueous dispersion for chemical mechanical polishing that suppresses deterioration of the polishing pad (for example, see Patent Document 3), iminodiacetic acid useful for correcting the wafer surface, and its A processing fluid containing a chelating agent selected from salts (for example, see Patent Document 4), a chemical mechanical polishing composition containing an α-amino acid (for example, see Patent Document 5), and the like have been proposed.
These technologies improve the polishing performance in copper wiring, but tantalum and its alloys, which are often used as barrier metal for copper wiring, are harder than copper. At present, it is desired to realize a polishing liquid having copper / tantalum selectivity.

JP 2001-127019 A JP 49-122432 A JP 2001-279231 A Special Table 2002-538284 JP 2003-507894 A

The present invention has been carried out based on the background that a CMP slurry that realizes faster polishing of wiring using copper metal and a copper alloy as a raw material is required in order to increase the productivity of LSI.
Accordingly, an object of the present invention is to provide a metal polishing liquid that has a rapid polishing rate and improves the copper / tantalum selectivity in polishing, thereby enabling the production of an LSI with less dishing and improved flatness. It is to provide.

式中、Ｒ^aはスルホ基、アミノ基、ホスホノ基（−ＰＯ₃Ｈ₂）、カルバモイル基（−ＣＯＮＲＲ’）、カルボンアミド基（−ＮＨＣＯＲ”）、スルファモイル基（−ＳＯ₂ＮＨ₂）、及びスルホンアミド基（−ＮＨＳＯ₂Ｒ”）からなる群より選択された少なくとも1つの置換基を表す。Ｒ及びＲ’はそれぞれ独立に水素原子、アルキル基及びアリール基から選ばれる基を表す。Ｒ”はそれぞれ独立にアルキル基及びアリール基から選ばれる基を表す。







一般式（ＩＩ）

式中、Ｒ^bはヒドロキシ基、カルボキシ基、スルホ基、アミノ基、ホスホノ基（−ＰＯ₃Ｈ₂）、カルバモイル基（−ＣＯＮＲＲ’）、カルボンアミド基（−ＮＨＣＯＲ”）、スルファモイル基（−ＳＯ₂ＮＨ₂）、及びスルホンアミド基（−ＮＨＳＯ₂Ｒ”）からなる群より選択された少なくとも1つの置換基を表す。Ｒ及びＲ’はそれぞれ独立に水素原子、アルキル基及びアリール基から選ばれる基を表す。Ｒ”はそれぞれ独立にアルキル基及びアリール基から選ばれる基を表す。Ｌ^bは二価の連結基を表す。
＜２＞ 半導体デバイスの化学的機械的平坦化において、主として銅配線の研磨に用いられることを特徴とする上記＜１＞に記載の金属用研磨液。 As a result of intensive studies on the problems associated with the above-described metal polishing liquid, the present inventors have found that the problem can be solved by using the following metal polishing liquid, and have completed the present invention. The present invention is as follows.
<1> A metal-polishing liquid used for chemical mechanical planarization of a semiconductor device, characterized by containing at least one tetrazole derivative represented by the following general formula (I) or (II): Polishing liquid for metal.
Formula (I)

In the formula, ^Ra is a sulfo group, an amino group, a phosphono group (—PO ₃ H ₂ ), a carbamoyl group (—CONRR ′), a carbonamido group (—NHCOR ″), a sulfamoyl group (—SO ₂ NH ₂ ), and It represents at least one substituent selected from the group consisting of a sulfonamide group (—NHSO ₂ R ″). R and R ′ each independently represents a group selected from a hydrogen atom, an alkyl group, and an aryl group. R ″ each independently represents a group selected from an alkyl group and an aryl group.







Formula (II)

In the formula, R ^b represents a hydroxy group, a carboxy group, a sulfo group, an amino group, a phosphono group (—PO ₃ H ₂ ), a carbamoyl group (—CONRR ′), a carbonamido group (—NHCOR ″), a sulfamoyl group (—SO ₂ NH ₂ ) and at least one substituent selected from the group consisting of a sulfonamide group (—NHSO ₂ R ″). R and R ′ each independently represents a group selected from a hydrogen atom, an alkyl group, and an aryl group. R ″ each independently represents a group selected from an alkyl group and an aryl group. L ^b represents a divalent linking group.
<2> The metal polishing slurry as described in <1> above, which is mainly used for polishing copper wiring in chemical mechanical planarization of semiconductor devices.

  By using the metal polishing liquid of the present invention as a polishing liquid used for chemical mechanical polishing in the manufacture of semiconductor devices, the chemical mechanical polishing rate is improved and the copper / tantalum selectivity in polishing is improved. In addition, it is possible to manufacture an LSI with less dishing and improved flatness. This also brings about an effect that the occurrence of defects due to local non-uniformity of polishing such as corrosion, scratching, thinning, erosion, etc. in LSI is maintained at a low level.

The metal polishing slurry of the present invention is characterized by having the following specific tetrazole derivatives. That is, it is a tetrazole derivative containing at least one specific substituent on the carbon atom of the tetrazole ring (hereinafter referred to as a specific tetrazole derivative as appropriate).
The tetrazole derivative represented by the general formula (I) of the present invention does not have a substituent on the nitrogen atom forming the tetrazole ring, and has a sulfo group at the 5-position (on the carbon atom) (R ^a ) of the tetrazole ring. Group (—SO ₃ H), amino group, phosphono group (—PO ₃ H ₂ ), carbamoyl group (—CONRR ′), carbonamido group (—NHCOR ″), sulfamoyl group (—SO ₂ NH ₂ ), and sulfone It represents at least one substituent selected from the group consisting of an amide group (—NHSO ₂ R ″). R and R ′ each independently represents a group selected from a hydrogen atom, an alkyl group and an aryl group, and a hydrogen atom or an alkyl group having about 1 to 3 carbon atoms is more preferable. R ″ represents a group independently selected from an alkyl group and an aryl group, and an alkyl group, particularly an alkyl group having about 1 to 3 carbon atoms, is more preferable.

Further, tetrazole derivative represented by the formula (II), has no substituent on the nitrogen atom to form a tetrazole ring, a divalent linking group represented in the 5-position of the tetrazole ring in L ^b Hydroxy group, carboxy group, sulfo group, amino group, phosphono group (—PO ₃ H ₂ ), carbamoyl group (—CONRR ′), carbonamido group (—NHCOR ″), sulfamoyl group (—SO ₂ NH ₂₎ ), And an alkylene group substituted with at least one substituent selected from the group consisting of a sulfonamide group (—NHSO ₂ R ″). R and R ′ each independently represents a group selected from a hydrogen atom, an alkyl group and an aryl group, and a hydrogen atom or an alkyl group having about 1 to 3 carbon atoms is more preferable. R ″ represents a group independently selected from an alkyl group and an aryl group, and an alkyl group, particularly an alkyl group having about 1 to 3 carbon atoms, is more preferable.

Examples of the divalent linking group represented by L ^b include an alkylene group, —S—, —O—, —NH—, —CO—, and combinations thereof. An alkylene group is preferable, and an alkylene group having 1 to 3 carbon atoms is more preferable.
L ^b may have a substituent other than R ^b , and examples of the substituent include an alkyl group having 1 to 3 carbon atoms and an aryl group having 6 to 12 carbon atoms, and these further have a substituent. You may do it. Further, the substituent which may be further substituted is preferably a hydroxy group or a carboxy group.
The tetrazole derivative of the present invention is preferably a tetrazole derivative represented by the general formula (II), more preferably R ^b is a hydroxy group or a carboxy group, and still more preferably a carboxy group. For example, 1H-tetrazole-5-acetic acid and 1H-tetrazole-5-succinic acid.

Specific examples of tetrazole derivatives that can be suitably used in the present invention are listed below, but the present invention is not limited thereto.

  The tetrazole derivatives of the present invention are commercially available, or Chemische Berichte, 34, 3120 (1901), Chemische Berichte, 89, 2648, (1956), Chemische Berichte, 34, 3120 (1901), Chemische Berichte, 89, 2652, (1956), Journal of Medicinal Chemistry, 29, 538-549 (1986), Carbohydrate Research, 73, 323-326 (1979).

In the metal polishing slurry of the present invention, the specific tetrazole derivative may be used alone or in combination of two or more.
The total amount of the specific tetrazole derivative contained in the metal polishing liquid of the present invention is preferably 0.00001 to 1 mol, more preferably 0.0001 to 1 L of the metal polishing liquid used for polishing. 0.5 mol, more preferably 0.0001 to 0.1 mol.

The metal-polishing liquid of the present invention is not particularly limited in its formulation except that it contains at least one of the specific tetrazole derivatives and a solvent / dispersion medium as constituent components. Usually, an oxidizing agent is added and used. . In addition, as long as the effects of the present invention are not impaired, compounds used in known metal polishing liquids can be selected and used depending on the purpose, but contain organic acids (for example, amino acid derivatives, carboxylic acid derivatives). It is preferable to do.
In general, the metal-polishing liquid contains an oxidizing agent, a passive film forming agent, an organic acid, and abrasive grains. In the present invention, it is not always necessary to add abrasive grains. The metal polishing slurry of the present invention may further contain other components, and preferred components include, for example, surfactants, water-soluble polymers, and various additives. Two or more of each component may be added to the metal polishing slurry.

  The “metal polishing liquid” in the present invention includes not only a polishing liquid used for polishing (that is, a polishing liquid diluted as necessary) but also a concentrated liquid of the metal polishing liquid. The concentrated liquid or the concentrated polishing liquid means a polishing liquid prepared with a higher solute concentration than the polishing liquid used for polishing, and is diluted with water or an aqueous solution when used for polishing. And used for polishing. The dilution factor is generally 1 to 20 volume times. In this specification, “concentration” and “concentrated liquid” are used in accordance with conventional expressions meaning “thick” and “thick liquid” rather than the state of use, and generally involve physical concentration operations such as evaporation. The term is used in a different way from the meaning of common terms.

In addition, among the components added when preparing the concentrate of the metal polishing liquid, the blending amount of water having a solubility in water at room temperature of less than 5% by mass is to prevent precipitation when the concentrate is cooled to 5 ° C. The solubility in water at room temperature is preferably within 2 times, more preferably within 1.5 times.
In this specification, “concentration” and “concentrated liquid” are used in accordance with conventional expressions meaning “thick” and “thick liquid” rather than the state of use, and physical concentration operations such as evaporation are performed. It is used in a different way from the meaning of the general terms involved.

Hereinafter, components other than the specific tetrazole derivative that can be used in the metal polishing liquid of the present invention will be described.
〔Oxidant〕
The metal polishing liquid of the present invention is usually used by adding a compound (oxidant) capable of oxidizing the metal to be polished. However, the oxidizing agent may be added immediately before use in order to prevent decomposition of the oxidizing agent. Therefore, in the present specification, a metal polishing liquid preliminary liquid that does not contain an oxidizing agent and adds an oxidizing agent immediately before use is also referred to as a “metal polishing liquid”. Examples of the acid oxidizing agent include hydrogen peroxide, peroxide, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, persulfate , Dichromate, permanganate, ozone water and silver (II) salt, iron (III) salt.

  Examples of iron (III) salts include inorganic iron (III) salts such as iron nitrate (III), iron chloride (III), iron sulfate (III), iron bromide (III), and organic iron (III) salts. Complex salts are preferably used.

  When an organic complex salt of iron (III) is used, examples of complex-forming compounds constituting the iron (III) complex salt include acetic acid, citric acid, oxalic acid, salicylic acid, diethyldithiocarbamic acid, succinic acid, tartaric acid, glycolic acid, glycine , Alanine, aspartic acid, thioglycolic acid, ethylenediamine, trimethylenediamine, diethylene glycol, triethylene glycol, 1,2-ethanedithiol, malonic acid, glutaric acid, 3-hydroxybutyric acid, propionic acid, phthalic acid, isophthalic acid, 3 Aminopolycarboxylic acid and its salt are mentioned other than -hydroxy salicylic acid, 3,5-dihydroxy salicylic acid, gallic acid, benzoic acid, maleic acid, etc. and these salts.

Examples of aminopolycarboxylic acids and salts thereof include ethylenediamine-N, N, N ′, N′-tetraacetic acid, diethylenetriaminepentaacetic acid, 1,3-diaminopropane-N, N, N ′, N′-tetraacetic acid, , 2-Diaminopropane-N, N, N ′, N′-tetraacetic acid, ethylenediamine-N, N′-disuccinic acid (racemic), ethylenediamine disuccinic acid (SS), N- (2-carboxylate ethyl) ) -L-aspartic acid, N- (carboxymethyl) -L-aspartic acid, β-alanine diacetic acid, methyliminodiacetic acid, nitrilotriacetic acid, cyclohexanediaminetetraacetic acid, iminodiacetic acid, glycol etherdiaminetetraacetic acid, ethylenediamine 1-N, N′-diacetic acid, ethylenediamine orthohydroxyphenylacetic acid, N, N-bis (2-hydroxybenzyl) ethylene Examples thereof include diamine-N, N-diacetic acid and salts thereof. The kind of the counter salt is preferably an alkali metal salt or an ammonium salt, and particularly preferably an ammonium salt.
Among these, hydrogen peroxide, nitric acid, potassium periodate, hypochlorous acid and ozone water are preferable.

  The addition amount of the oxidizing agent is preferably 0.003 mol to 8 mol, more preferably 0.03 mol to 6 mol, and more preferably 0.1 mol to 4 mol in 1 liter of the metal polishing liquid used for polishing. It is particularly preferable to do this. 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.

[Organic acid]
It is preferable to use an organic acid in combination with the polishing liquid of the present invention. The organic acid here is a compound having a structure different from that of an oxidizing agent for oxidizing a metal, and does not include an acid that functions as the oxidizing agent.
As the organic acid, one selected from the following group is suitable. 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, lactic acid, and amino acids (amino acids include primary, secondary, tertiary amino acids and aminopolycarboxylic acids, and water-soluble ones are preferred in the present invention. For example, glycine, L -Alanine, β-alanine, L-2-aminobutyric acid, L-norvaline, L-valine, L-leucine, L-norleucine, L-isoleucine, L- Loisoleucine, 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-cystine acid, L-aspartic acid, L-glutamic acid, S- (carboxymethyl) -L-cysteine, 4-aminobutyric acid, L-asparagine, L-glutamine, azaserine, L-arginine, L -Canavanine, L-citrulline, δ-hydroxy-L-lysine, creatine, L-quinu Nin, L-histidine, 1-methyl-L-histidine, 3-methyl-L-histidine, ergothioneine, L-tryptophan, actinomycin C1, apamin, angiotensin I, angiotensin II and antipine. Examples thereof include compounds represented by general formula (1) and general formula (2), and ammonium salts and alkali metal salts thereof.

General formula (1)

R ₁ represents a single bond, an alkylene group, or a phenylene group. R ₂ and R ₃ each independently represents a hydrogen atom, a halogen atom, a carboxyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, or an aryl group. R ₄ and R ₅ each independently represents a hydrogen atom, a halogen atom, a carboxyl group, an alkyl group, or an acyl group. However, when R ₁ is a single bond, at least one of R ₄ and R ₅ is not a hydrogen atom.
General formula (2)

R ₆ represents a single bond, an alkylene group, or a phenylene group. R ₇ and R ₈ each independently represents a hydrogen atom, a halogen atom, a carboxyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, or an aryl group. R ₉ represents a hydrogen atom, a halogen atom, a carboxyl group, or an alkyl group. R ₁₀ represents an alkylene group. However, when R ₁₀ is —CH ₂ —, R ₆ is not a single bond or R ₉ is not a hydrogen atom.

The alkylene group as R ₁ in Formula (1) may be linear, branched or cyclic, and preferably has 1 to 8 carbon atoms, and examples thereof include a methylene group and an ethylene group. it can. Examples of the substituent that the alkylene group may have include a hydroxyl group and a halogen atom.

The alkyl group as R ₂ and R ₃ preferably has 1 to 8 carbon atoms, and examples thereof include a methyl group and a propyl group. The cycloalkyl group as R ₂ and R ₃ preferably has 5 to 15 carbon atoms, and examples thereof include a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. The alkenyl group as R ₂ and R ₃ preferably has 2 to 9 carbon atoms, and examples thereof include a vinyl group, a propenyl group, and an allyl group. The alkynyl group as R ₂ and R ₃ preferably has 2 to 9 carbon atoms, and examples thereof include an ethynyl group, a propynyl group, and a butynyl group.

The aryl group as R ₂ and R ₃ preferably has 6 to 15 carbon atoms, and examples thereof include a phenyl group. The alkylene chain in these groups may have a hetero atom such as an oxygen atom or a sulfur atom. Examples of the substituent that each group represented by R ₂ and R ₃ may have include a hydroxyl group, a halogen atom, an aromatic ring (preferably having 3 to 15 carbon atoms), a carboxyl group, and an amino group.

The alkyl group as R ₄ and R ₅ preferably has 1 to 8 carbon atoms, and examples thereof include a methyl group and an ethyl group. The acyl group preferably has 2 to 9 carbon atoms, and examples thereof include a methylcarbonyl group. Examples of the substituent that each group as R ₄ and R ₅ may have include a hydroxyl group, an amino group, and a halogen atom.

In general formula (1), it is preferable that either one of R ₄ and R ₅ is not a hydrogen atom.
In the general formula (1), it is particularly preferable that R ₁ is a single bond, and R ₂ and R ₄ are hydrogen atoms. In this case, R ₃ represents a hydrogen atom, a halogen atom, a carboxyl group, an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, or an aryl group, and particularly preferably a hydrogen atom or an alkyl group. R ₅ represents a hydrogen atom, a halogen atom, a carboxyl group, an alkyl group, or an acyl group, and an alkyl group is particularly preferable. As the substituent that the alkyl group as R ₃ may have, a hydroxyl group, a carboxyl group, or an amino group is preferable. As the substituent that the alkyl group as R ₅ may have, a hydroxyl group or an amino group is preferable.

The alkylene group as R ₆ and R ₁₀ in formula (2) may be linear, branched or cyclic, and preferably has 1 to 8 carbon atoms. For example, a methylene group or an ethylene group Can be mentioned. Examples of the substituent that the alkylene group and the phenylene group may have include a hydroxyl group and a halogen atom.

The alkyl group as R ₇ and R ₈ preferably has 1 to 8 carbon atoms, and examples thereof include a methyl group and a propyl group. The cycloalkyl group as R ₇ and R ₈ preferably has 5 to 15 carbon atoms, and examples thereof include a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. The alkenyl group as R ₇ and R ₈ preferably has 2 to 9 carbon atoms, and examples thereof include a vinyl group, a propenyl group, and an allyl group. The alkynyl group as R ₇ and R ₈ preferably has 2 to 9 carbon atoms, and examples thereof include an ethynyl group, a propynyl group, and a butynyl group.

The aryl group as R ₇ and R ₈ preferably has 6 to 15 carbon atoms, and examples thereof include a phenyl group. The alkylene chain in these groups may have a hetero atom such as an oxygen atom or a sulfur atom. Examples of the substituent that each group represented by R ₇ and R ₈ may have include a hydroxyl group, a halogen atom, and an aromatic ring (preferably having 3 to 15 carbon atoms).

The alkyl group as R ₉ preferably has 1 to 8 carbon atoms, and examples thereof include a methyl group and an ethyl group. The acyl group as R ₉ preferably has 2 to 9 carbon atoms, and examples thereof include a methylcarbonyl group. The alkylene chain in these groups may have a hetero atom such as an oxygen atom or a sulfur atom. Examples of the substituent that each group as R ₉ may have include a hydroxyl group, an amino group, a halogen atom, and a carboxyl group.
In the general formula (2), R ₉ is preferably not a hydrogen atom.

Although the specific example of a compound represented by General formula (1) or General formula (2) below is given, it does not limit to these.

  The compound represented by the general formula (1) or (2) can be synthesized by a known method, but a commercially available product may be used.

  In particular, as the organic acid, amino acid derivatives containing the general formulas (1) and (2) are preferable in that the etching rate can be effectively suppressed while maintaining a practical CMP rate.

  The addition amount of the organic acid is preferably 0.0005 to 0.5 mol, more preferably 0.005 to 0.3 mol in 1 L of the metal polishing liquid used for polishing. It is especially preferable to set it as 01 mol-0.1 mol. That is, the amount of acid added is preferably 0.5 mol or less from the viewpoint of suppressing etching, and 0.0005 mol or more is preferable for obtaining a sufficient effect.

[Inorganic acid]
An inorganic acid can be further added to the polishing liquid of the present invention. The acid here has an action of promoting oxidation, adjusting pH, and buffering agent. Examples of the inorganic acid include sulfuric acid, nitric acid, boric acid, phosphoric acid, etc. Among the inorganic acids, phosphoric acid is preferable.
The amount of acid added is preferably 0.0005 to 0.5 mol, more preferably 0.005 mol to 0.3 mol, in 1 L of the metal polishing liquid used for polishing, and 0.01 mol. It is especially preferable to set it to -0.1 mol. That is, the amount of acid added is preferably 0.5 mol or less from the viewpoint of suppressing etching, and 0.0005 mol or more is preferable for obtaining a sufficient effect.

[Passive film forming agent (compound having an aromatic ring)]
In addition, the metal polishing liquid in the present invention is used as a passive film forming agent that suppresses deterioration of an oxidizing agent in addition to a specific tetrazole derivative, forms a passive film on the metal surface, and controls the polishing rate. A compound having a function, specifically, a compound having an aromatic ring may be used in combination.
The compound having an aromatic ring is a compound having an aromatic ring such as a benzene ring or a naphthalene ring, preferably having a molecular weight of 20 to 600, such as tetrazole and derivatives thereof, or anthranilic acids and derivatives thereof, aminotoluic acid, and quinaldine. Examples of the acid include the following azoles.

  The azoles as compounds having an aromatic ring are benzimidazole-2-thiol, 2- [2- (benzothiazolyl)] thiopropionic acid, 2- [2- (benzothiazolyl)] thiobutyric acid, 2-mercaptobenzothiazole, 1 , 2,3-triazole, 1,2,4-triazole, 3-amino-1H-1,2,4-triazole, benzotriazole, 1-hydroxybenzotriazole, 1-dihydroxypropylbenzotriazole, 2,3-di Carboxypropylbenzotriazole, 4-hydroxybenzotriazole, 4-carboxyl-1H-benzotriazole, 4-methoxycarbonyl-1H-benzotriazole, 4-butoxycarbonyl-1H-benzotriazole, 4-octyloxycarbonyl-1H-benzo Riazole, 5-hexylbenzotriazole, N- (1,2,3-benzotriazolyl-1-methyl) -N- (1,2,4-triazolyl-1-methyl) -2-ethylhexylamine, tolyltriazole , Naphthotriazole, bis [(1-benzotriazolyl) methyl] phosphonic acid and the like, benzotriazole, 4-hydroxybenzotriazole, 4-carboxyl-1H-benzotriazole butyl ester, tolyltriazole, naphthotriazole are high This is preferable for achieving both a CMP rate and a low etching rate.

The total amount of the compound having an aromatic ring is, as a total amount, a metal polishing liquid used for polishing (that is, a diluted polishing liquid when diluted with water or an aqueous solution. In 1 liter) is preferably 0.0001 to 1.0 mol, more preferably 0.001 to 0.5 mol, and still more preferably 0.01 to 0.1 mol.
That is, the addition amount of the compound having an aromatic ring is preferably 1.0 mol or less in 1 L of polishing liquid when used for polishing from the viewpoint of oxidizing agent and prevention of deterioration (invalidation, decomposition) of these compounds, and sufficient effect. Is preferably 0.0001 mol or more.
In addition, you may use together thiocyanate, thioethers, thiosulfate, or a meso ion compound with the addition amount smaller than the addition amount of the compound which has an aromatic ring.

[Chelating agent]
The metal polishing liquid of the present invention preferably contains a chelating agent (that is, a hard water softening agent) as necessary in order to reduce adverse effects such as mixed polyvalent metal ions.
Chelating agents include general water softeners and related compounds that are calcium and magnesium precipitation inhibitors, such as 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 diacetic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, N N'-bis (2-hydroxyben Zyl) ethylenediamine-N, N′-diacetic acid, 1,2-dihydroxybenzene-4,6-disulfonic acid and the like.

  Two or more chelating agents may be used in combination as necessary. The addition amount of the chelating agent may be an amount sufficient to sequester metal ions such as mixed polyvalent metal ions. For example, 0.0003 mol to 0 in 1 L of a metal polishing liquid used for polishing. 0.07 mol is added.

〔Additive〕
Moreover, it is preferable to use the following additives for the metal polishing slurry of the present invention. Ammonia; alkylamines such as dimethylamine, trimethylamine, triethylamine and propylenediamine; amines such as ethylenediaminetetraacetic acid (EDTA), sodium diethyldithiocarbamate and chitosan; dithizone, cuproin (2,2'-biquinoline), neocuproin (2, Imines such as 9-dimethyl-1,10-phenanthroline), bathocuproine (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and cuperazone (biscyclohexanone oxalyl hydrazone); benzimidazole-2-thiol, 2- [2- (benzothiazolyl)] thiopropionic acid, 2- [2- (benzothiazolyl)] thiobutyric acid, 2-mercaptobenzothiazole, 1,2,3-triazole, 1,2,4- Triazole, 3-amino-1H-1,2,4-triazole, benzotriazole, 1-hydroxybenzotriazole, 1-dihydroxypropylbenzotriazole, 2,3-dicarboxypropylbenzotriazole, 4-hydroxybenzotriazole, 4- Carboxyl-1H-benzotriazole, 4-methoxycarbonyl-1H-benzotriazole, 4-butoxycarbonyl-1H-benzotriazole, 4-octyloxycarbonyl-1H-benzotriazole, 5-hexylbenzotriazole, N- (1,2 , 3-Benzotriazolyl-1-methyl) -N- (1,2,4-triazolyl-1-methyl) -2-ethylhexylamine, tolyltriazole, naphthotriazole, bis [(1-benzotriazolyl) Chill] azole such as phosphonic acid; nonyl mercaptan, dodecyl mercaptan, triazine thiol, triazine dithiol, mercaptan triazine trithiol etc., other, anthranilic acid, Aminotoruiru acid, quinaldic acid. Among these, chitosan, ethylenediaminetetraacetic acid, L-tryptophan, cuperazone, triazinedithiol, benzotriazole, 4-hydroxybenzotriazole, 4-carboxyl-1H-benzotriazole butyl ester, tolyltriazole, naphthotriazole have high CMP rate and low etching It is preferable for achieving both speeds.

  The addition amount of these additives is preferably 0.0001 mol to 0.5 mol, more preferably 0.001 mol to 0.2 mol, in 1 L of the metal polishing liquid used for polishing. It is especially preferable to set it as 005 mol-0.1 mol. That is, the addition amount of the additive is preferably 0.0001 mol or more from the viewpoint of suppressing etching, and preferably 0.5 mol or less from the viewpoint of preventing a decrease in CMP rate.

[Surfactant and / or hydrophilic polymer]
The metal polishing slurry of the present invention preferably contains a surfactant and / 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 / or hydrophilic polymer to be used, those selected from the following group are suitable.
Examples of the anionic surfactant include carboxylate, sulfonate, sulfate ester salt and phosphate ester salt. As the carboxylate salt, soap, N-acyl amino acid salt, polyoxyethylene or polyoxypropylene alkyl ether carboxyl Acid salt, acylated peptide; as sulfonate, alkyl sulfonate, alkyl benzene and alkyl naphthalene sulfonate, naphthalene sulfonate, sulfosuccinate, α-olefin sulfonate, N-acyl sulfonate; sulfate ester Salts include sulfated oil, alkyl sulfates, alkyl ether sulfates, polyoxyethylene or polyoxypropylene alkyl allyl ether sulfates, alkyl amide sulfates; phosphate ester salts such as alkyl phosphates, polyoxyethylene or polyoxy B pyrene alkyl allyl ether phosphate can be exemplified.

As cationic surfactant, aliphatic amine salt, aliphatic quaternary ammonium salt, benzalkonium chloride salt, benzethonium chloride, pyridinium salt, imidazolinium salt; carboxybetaine type, aminocarboxylate as amphoteric surfactant And imidazolinium betaine, lecithin, and alkylamine oxide.
Nonionic surfactants include ether type, ether ester type, ester type and nitrogen-containing type. Ether type includes polyoxyethylene alkyl and alkylphenyl ether, alkylallyl formaldehyde condensed polyoxyethylene ether, polyoxyethylene poly Examples include oxypropylene block polymer, polyoxyethylene polyoxypropylene alkyl ether, ether ester type, glycerin ester polyoxyethylene ether, sorbitan ester polyoxyethylene ether, sorbitol ester polyoxyethylene ether, ester type, Polyethylene glycol fatty acid ester, glycerin ester, polyglycerin ester, sorbitan ester, propylene glycol ester Le, sucrose esters, nitrogen-containing type, fatty acid alkanolamides, polyoxyethylene fatty acid amides, polyoxyethylene alkyl amide, and the like. Moreover, a fluorine-type surfactant etc. are mentioned.

  Furthermore, other surfactants, hydrophilic compounds, hydrophilic polymers and the like include esters such as glycerin ester, sorbitan ester, methoxyacetic acid, ethoxyacetic acid, 3-ethoxypropionic acid and alanine ethyl ester; polyethylene glycol, polypropylene glycol, Polytetramethylene glycol, polyethylene glycol alkyl ether, polyethylene glycol alkenyl ether, alkyl polyethylene glycol, alkyl polyethylene glycol alkyl ether, alkyl polyethylene glycol alkenyl ether, alkenyl polyethylene glycol, alkenyl polyethylene glycol alkyl ether, alkenyl polyethylene glycol alkenyl ether, polypropylene glycol alkyl Ete , Polypropylene glycol alkenyl ethers, alkyl polypropylene glycols, alkyl polypropylene glycol alkyl ethers, alkyl polypropylene glycol alkenyl ethers, alkenyl polypropylene glycols, alkenyl polypropylene glycol alkyl ethers and alkenyl polypropylene glycol alkenyl ethers; alginic acid, pectinic acid, carboxymethylcellulose, curd Polysaccharides such as orchid and pullulan; amino acid salts such as glycine ammonium salt and glycine sodium salt; polyaspartic acid, polyglutamic acid, polylysine, polymalic acid, polymethacrylic acid, polymethacrylic acid ammonium salt, polymethacrylic acid sodium salt, polyamic acid , Polymaleic acid, poly Taconic acid, polyfumaric acid, poly (p-styrenecarboxylic acid), polyacrylic acid, polyacrylamide, aminopolyacrylamide, polyacrylic acid ammonium salt, polyacrylic acid sodium salt, polyamic acid, polyamic acid ammonium salt, polyamic acid sodium salt And polycarboxylic acids such as polyglyoxylic acid and salts thereof; vinyl polymers such as polyvinyl alcohol, polyvinylpyrrolidone and polyacrolein; methyl taurate ammonium salt, methyl taurate sodium salt, methyl sodium sulfate salt, ethylammonium sulfate salt, sulfuric acid Butylammonium salt, vinylsulfonic acid sodium salt, 1-allylsulfonic acid sodium salt, 2-allylsulfonic acid sodium salt, methoxymethylsulfonic acid sodium salt, ethoxymethyls Sulfonic acid and its salts such as ammonium sulfonate, 3-ethoxypropyl sulfonate, sodium methoxymethyl sulfonate, ammonium ethoxymethyl sulfonate, sodium 3-ethoxypropyl sulfonate and sodium sulfosuccinate; propion Amides such as amide, acrylamide, methylurea, nicotinamide, succinic acid amide and sulfanilamide are exemplified.

  However, when the substrate to be applied is a silicon substrate for a semiconductor integrated circuit or the like, contamination with an alkali metal, an alkaline earth metal, a halide, or the like is not desirable, so an acid or an ammonium salt thereof is desirable. This is not the case when the substrate is a glass substrate or 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 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. That is, the addition amount of the surfactant and / or the hydrophilic polymer is preferably 0.001 g or more for obtaining a sufficient effect, and is preferably 10 g or less from the viewpoint of preventing the CMP rate from being lowered. Moreover, as a weight average molecular weight of these surfactant and / or hydrophilic polymer, 500-100000 are preferable, and 2000-50000 are especially preferable.

[Alkaline agent and buffer]
The polishing liquid of the present invention can contain an alkali agent for pH adjustment and further a buffering agent from the viewpoint of suppressing fluctuations in pH, if necessary.

  Alkaline agents and buffering agents include organic ammonium hydroxides such as ammonium hydroxide and tetramethylammonium hydroxide, nonmetallic alkali agents such as alkanolamines such as diethanolamine, triethanolamine, triisopropanolamine, and the like. Alkali metal hydroxides such as sodium, potassium hydroxide and lithium hydroxide, carbonate, phosphate, borate, tetraborate, hydroxybenzoate, glycyl salt, N, N-dimethylglycine salt, leucine Salt, norleucine salt, guanine salt, 3,4-dihydroxyphenylalanine salt, alanine salt, aminobutyrate, 2-amino-2-methyl-1,3-propanediol salt, valine salt, proline salt, trishydroxyaminomethane salt Lysine salts can be used That.

Specific examples of the alkali agent and buffer include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, trisodium phosphate, tripotassium phosphate, diphosphate phosphate. Sodium, dipotassium phosphate, sodium borate, potassium borate, sodium tetraborate (borax), potassium tetraborate, sodium o-hydroxybenzoate (sodium salicylate), potassium o-hydroxybenzoate, 5-sulfo Examples include sodium 2-hydroxybenzoate (sodium 5-sulfosalicylate), potassium 5-sulfo-2-hydroxybenzoate (potassium 5-sulfosalicylate), ammonium hydroxide, and the like.
Particularly preferred alkali agents are ammonium hydroxide, potassium hydroxide, lithium hydroxide and tetramethylammonium hydroxide.

The addition amount of the alkaline agent and the buffer may be an amount that maintains the pH within a preferable range, and is preferably 0.0001 mol to 1.0 mol in 1 L of the polishing liquid used for polishing. More preferably, it is 0.003 mol to 0.5 mol.
The pH of the polishing liquid when used for polishing is preferably 2 to 14, more preferably 3 to 12, and most preferably 3.5 to 8. Within this range, the metal liquid of the present invention exhibits particularly excellent effects.

  In the present invention, depending on the adsorptivity and reactivity to the polishing surface, the solubility of the polishing metal, the electrochemical properties of the surface to be polished, the dissociation state of the compound functional group, the stability as a liquid, etc. It is preferable to set the amount and pH.

[Abrasive]
The metal polishing liquid of the present invention may contain 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. It is done.
The average grain size of the abrasive grains is preferably 5 to 1000 nm, and particularly preferably 10 to 200 nm.
As addition amount of an abrasive grain, it is preferable that an abrasive grain is 0.01-20 mass% with respect to the total mass of the polishing liquid for metals at the time of use, and is the range of 0.05-5 mass%. It is more preferable. 0.01% by mass or more is preferable for obtaining a sufficient effect in improving the polishing rate and reducing variation in the polishing rate within the wafer surface, and 20% by mass or less is preferable because the polishing rate by CMP is saturated.

[Raw metal materials]
In the present invention, the semiconductor to be polished is preferably an LSI having wiring made of copper metal and / or copper alloy, and particularly preferably a copper alloy. In the present invention, the term “mainly used for polishing copper wiring” means that a metal polishing liquid is used to polish a semiconductor wafer plated with copper metal and / or copper alloy. Pointing. Furthermore, the copper alloy containing silver is preferable among copper alloys. The silver content contained in the copper alloy is preferably 40% by mass or less, particularly 10% by mass or less, more preferably 1% by mass or less, and most preferably in the range of 0.00001 to 0.1% by mass. Exhibits excellent effects.

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

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

[Polishing method]
The metal polishing liquid is a concentrated liquid, and when used, it is diluted with water to make a working liquid, or each component is mixed in the form of an aqueous solution described in the next section, and water is added if necessary. In some cases, it is used as a working solution after dilution. The polishing method using the metal polishing liquid of the present invention can be applied to any case, and the polishing liquid is supplied to the polishing pad on the polishing surface plate and brought into contact with the surface to be polished to thereby connect the surface to be polished and the polishing pad. This is a polishing method in which polishing is performed by relative movement.
As an apparatus for polishing, there is a general polishing apparatus having a polishing surface plate with a holder for holding a semiconductor substrate having a surface to be polished and a polishing pad attached (a motor etc. capable of changing the number of rotations is attached). Can be used. As the polishing pad, a general nonwoven fabric, foamed polyurethane, porous fluororesin, or the like can be used, and there is no particular limitation. The polishing conditions are not limited, but the rotation speed of the polishing surface plate is preferably a low rotation of 200 rpm or less so that the substrate does not jump out. The pressure applied to the polishing pad of the semiconductor substrate having the surface to be polished (film to be polished) is preferably ⁵ to 500 g / cm ² in order to satisfy the uniformity of the polishing rate within the wafer surface and the flatness of the pattern. Is more preferably 12 to 240 g / cm ² .

  During polishing, a polishing liquid for metal is continuously supplied to the polishing pad with a pump or the like. 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. The semiconductor substrate after polishing is thoroughly washed in running water, and then dried after removing water droplets adhering to the semiconductor substrate using a spin dryer or the like. In the polishing method of the present invention, the aqueous solution to be diluted is the same as the aqueous solution described below. The aqueous solution is water that contains at least one of an oxidizing agent, an acid, an additive, and a surfactant in advance, and the total amount of the components contained in the aqueous solution and the components of the metal polishing liquid to be diluted is a metal. It becomes the component at the time of grinding | polishing using the polishing liquid. When diluted with an aqueous solution and used, components that are difficult to dissolve can be blended in the form of an aqueous solution, and a more concentrated metal polishing liquid can be prepared.

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

  The supply rate of the metal polishing liquid is preferably 10 to 1000 ml / min, and more preferably 170 to 800 ml / min in order to satisfy the uniformity of the polishing rate within the wafer surface and the flatness of the pattern.

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

According to another polishing method of the present invention, a component to be contained in a metal polishing liquid is divided into at least two components, and when using them, a water or aqueous solution is added to dilute the polishing pad on a polishing platen. The surface to be polished is brought into contact with the surface to be polished, and the surface to be polished and the polishing pad are moved relative to each other for polishing.
For example, an oxidizing agent is one component (A), an acid, an additive, a surfactant, and water are one component (B), and when they are used, the component (A) The component (B) is diluted before use.
In addition, the low-solubility additive is divided into two components (A) and (B), and the oxidizing agent, additive and surfactant are one component (A), and the acid, additive, surfactant and Water is used as one component (B), and when these are used, water or an aqueous solution is added to dilute the component (A) and the component (B). In the case of this example, three pipes for supplying the component (A), the component (B), and water or an aqueous solution are required, and dilution mixing is performed on one pipe that supplies the three pads to the polishing pad. There is a method of combining and mixing in the pipe. In this case, it is also possible to combine two pipes and then connect another pipe.
Here, the specific heterocyclic derivative according to the present invention is preferably added to (B) together with the organic acid among the two constituent components from the viewpoint of solution aging stability.

  For example, it is a method in which a component containing an additive that is difficult to dissolve is mixed with another component, a mixing path is lengthened to ensure a dissolution time, and then a pipe for water or an aqueous solution is further combined. Other mixing methods are as described above, in which the three pipes are each guided directly to the polishing pad and mixed by the relative movement of the polishing pad and the surface to be polished, and the three components are mixed in one container. A method for supplying a diluted metal polishing liquid to a polishing pad. In the above polishing method, one constituent component containing an oxidizing agent is made 40 ° C. or lower, the other constituent components are heated in the range of room temperature to 100 ° C., and one constituent component and another constituent component or water or an aqueous solution When the mixture is diluted and used, it can be adjusted to 40 ° C. or lower after mixing. Since the solubility increases when the temperature is high, this is a preferable method for increasing the solubility of the raw material having a low solubility in the metal polishing slurry.

  A raw material in which other components not containing an oxidizing agent are heated and dissolved in the range of room temperature to 100 ° C. is precipitated in the solution when the temperature is lowered. It is necessary to dissolve what is deposited by heating. For this, a means for feeding a heated component solution and a means for stirring the liquid containing the precipitate, feeding the liquid, and heating and dissolving the pipe can be employed. When the temperature of one component containing an oxidant is increased to 40 ° C. or higher, the oxidant may be decomposed. Therefore, the heated component and the oxidation for cooling the heated component When mixed with one component containing an agent, the temperature is set to 40 ° C. or lower.

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

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

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

More preferred embodiments in the present invention are as follows.
(1) A metal-polishing liquid comprising a compound of the present invention in combination with at least one compound selected from the group of compounds represented by formulas (1) and (2) as an organic acid.
(2) As an organic acid, the compound of the present invention is used in combination with at least one compound selected from the group of compounds represented by general formula (1) and general formula (2), and the compound of the present invention is added in an amount of 1 mmol / L or less. A metal polishing liquid characterized by the above.
(3) The organic compound is used in combination with at least one compound selected from the group of compounds represented by general formula (1) and general formula (2) as the organic acid, and the present compound is 0.5 mmol / L or less. A polishing liquid for metals characterized by being added.
(4) As a metal polishing liquid for polishing at a pressing pressure of 75 g / cm ² or less, at least one compound selected from the group of compounds represented by the general formula (1) and the general formula (2) as an organic acid and the present A metal-polishing liquid characterized by using the inventive compound in combination and adding the present compound to 0.5 mmol / L or less.

Hereinafter, the present invention will be described by way of examples. The present invention is not limited to these examples.
<Example 1>
A polishing liquid was prepared according to the following formulation (metal polishing liquid 1), and a metal polishing liquid of Example 1 was obtained. This metal polishing liquid was evaluated by conducting a polishing test by the following method.
(Metal polishing liquid 1)
Hydrogen peroxide (oxidant) 5g / L
Glycine (organic acid) 0.2 mol / L
Illustrative compound I-1 (specific tetrazole derivative) 0.2 mmol / L
Colloidal silica (abrasive) 9g / L
Add pure water, total volume 1000mL
pH (adjusted with aqueous ammonia and sulfuric acid) 6.7

(Polishing test)
Polishing pad: IC1400XY-K Groove (Rodale)
Polishing machine: LGP-612 (LapmaSterSFT)
Holding pressure: 75 g / cm ²
Polishing liquid supply rate: 200 ml / min
Copper blanket wafer: Wafer (200 mm) on which a copper film with a thickness of 1.4 μm is formed
Tantalum blanket wafer: Wafer (200 mm) on which a tantalum film with a thickness of 1 μm is formed
Pattern wafer: CMP854 pattern wafer (200 mm) manufactured by Sematec
Polishing pad / wafer rotation speed: 95/120 rpm
Surface plate temperature control: 20 ° C

(Evaluation methods)
Polishing rate: The average polishing rate was determined by converting the film thickness of the metal film before and after CMP from an electric resistance value at any 49 locations on the copper or tantalum blanket wafer surface.
Dishing: In addition to the time until the copper in the non-wiring portion is completely polished, the pattern wafer is polished for a time corresponding to 50% of the time, and the dishing of the line and space portion (line 100 μm, space 100 μm) is performed. Was measured with a stylus profilometer.
Table 3 below shows the polishing rate, dishing, and the polishing rate ratio of copper and tantalum obtained by performing CMP using the above polishing liquid.

<Examples 2-5 and Comparative Examples 1-6>
In the formulation of the metal polishing slurry 1 in Example 1, Exemplified Compound I-1 which is a specific tetrazole derivative and glycine which is an organic acid were changed to the compounds shown in Table 3, respectively, in the same manner as in Example 1. The metal polishing liquids of Examples 2 to 5 and Comparative Examples 1 to 6 were prepared, and the polishing test was conducted in the same manner as in Example 1. The results are also shown in Table 3 below.

^*：ビシン（Bicine）＝“N,N-ビス(2-ヒドロキシエチル)グリシン”

^* : Bicine = “N, N-bis (2-hydroxyethyl) glycine”

  As shown in Table 3, the metal polishing liquid of the present invention containing the specific tetrazole derivative of the present invention is a heterocycle having no specific functional group of the present invention, such as benzotriazole or unsubstituted 1H-tetrazole. It can be seen that the polishing liquid containing the derivative is excellent in polishing rate and dishing. Moreover, it became clear that the polishing liquid for metals of this invention has a high polishing selectivity of copper and tantalum.

Claims (2)

A metal polishing liquid used for chemical mechanical planarization of a semiconductor device, comprising at least one tetrazole derivative represented by the following general formula (I) or (II): Polishing fluid.
Formula (I)

In the formula, ^Ra is a sulfo group, an amino group, a phosphono group (—PO ₃ H ₂ ), a carbamoyl group (—CONRR ′), a carbonamido group (—NHCOR ″), a sulfamoyl group (—SO ₂ NH ₂ ), and It represents at least one substituent selected from the group consisting of a sulfonamide group (—NHSO ₂ R ″). R and R ′ each independently represents a group selected from a hydrogen atom, an alkyl group, and an aryl group. R ″ each independently represents a group selected from an alkyl group and an aryl group.
Formula (II)

In the formula, R ^b represents a hydroxy group, a carboxy group, a sulfo group, an amino group, a phosphono group (—PO ₃ H ₂ ), a carbamoyl group (—CONRR ′), a carbonamido group (—NHCOR ″), a sulfamoyl group (—SO ₂ NH ₂ ) and at least one substituent selected from the group consisting of a sulfonamide group (—NHSO ₂ R ″). R and R ′ each independently represents a group selected from a hydrogen atom, an alkyl group, and an aryl group. R ″ each independently represents a group selected from an alkyl group and an aryl group. L ^b represents a divalent linking group. The metal-polishing liquid according to claim 1, wherein the metal-polishing liquid is mainly used for polishing a copper wiring in chemical mechanical planarization of a semiconductor device.