JP2008078221A - Polishing solution for metal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing solution for metal assuring quick chemical and mechanical polishing speed, improving flatness with less dishing and enabling manufacture of LSI where a groove is rarely formed between a copper wire and a barrier layer. <P>SOLUTION: The polishing solution for metal materials used for realizing chemical and mechanical flatness of a semiconductor device is characterized in including an amino acidic derivative having at least one tetrazole ring or triazole ring, for example, the amino acidic derivative expressed by an general expression (I). <P>COPYRIGHT: (C)2008,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 electron 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. This is beginning to be considered. 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 manufacturing of a diameter of 300 mm or more has 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.
Although these techniques can improve the polishing performance in copper wiring, there is a problem that a groove is formed between the copper wiring and the barrier layer (see FIG. 1), and it is possible to realize a polishing liquid that does not cause it. What is desired is the current situation.

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, has less dishing, improves flatness, and hardly forms a groove between a copper wiring and a barrier layer.

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, comprising an amino acid derivative having at least one tetrazole ring or triazole ring.
<2> The metal polishing slurry according to <1>, wherein the amino acid derivative having at least one tetrazole ring or triazole ring is an amino acid derivative represented by the following general formula (I).

一般式（I）
式中、Ｌ^aおよびＬ^bは置換基を有してもよい２価の連結基を表す。Ｒは、水素原子または置換基を表す。Hetはテトラゾール環またはトリアゾール環を表す。
＜３＞ 前記金属研磨液が、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＜１＞または＜２＞に記載の金属用研磨液。

Formula (I)
In the formula, L ^a and L ^b represent a divalent linking group which may have a substituent. R represents a hydrogen atom or a substituent. Het represents a tetrazole ring or a triazole ring.
<3> The metal polishing liquid according to <1> or <2>, wherein the metal polishing liquid is mainly used for polishing copper wiring in chemical mechanical planarization of a semiconductor device.

  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 occurrence of dishing is reduced and the flatness is improved. Further, it is possible to manufacture an LSI in which it is difficult to form a groove between the copper wiring and the barrier layer. This also brings about an effect that the generation of defects due to local non-uniformity of polishing such as corrosion, scratching, thinning, and erosion in LSI is maintained at a low level.

  The metal polishing slurry of the present invention is characterized by having an amino acid derivative containing at least one tetrazole ring or triazole ring. The reason why the groove is formed between the copper wiring and the barrier layer is not clear, but is thought to be due to some etching action. By using the metal polishing liquid containing the amino acid derivative, the etching action is suppressed and the formation of grooves can be suppressed while maintaining the copper polishing rate and also suppressing the occurrence of dishing.

Examples of the tetrazole ring in the amino acid derivative include a 1H-tetrazole ring. Examples of the triazole ring include a 1,2,3-triazole ring and a 1,2,4-triazole ring, and a 1,2,3-triazole ring is preferable.
The tetrazole ring and triazole ring may be substituted at any position of the amino acid derivative, but are preferably on the alkyl group or aryl group, more preferably on the alkyl group, and still more preferably the terminal of the alkyl group.
The position at which the tetrazole ring is linked to the amino acid skeleton is preferably the first position (on the nitrogen atom) or the fifth position (on the carbon atom) of the tetrazole ring, and more preferably the fifth position.
The position at which the triazole ring is linked to the amino acid skeleton is preferably the 4-position or 5-position of the 1,2,3-triazole ring, and the 3-position or 5-position of the 1,2,4-triazole ring is preferred.

The linking group that connects the tetrazole ring or triazole ring and the amino acid skeleton is preferably any divalent linking group, but is preferably an alkylene group, more preferably methylene, ethylene, or trimethylene.
The number of tetrazole or triazole rings contained in the amino acid derivative of the present invention is preferably 1 or 2, but more preferably 1.

The number of carboxyl groups of the amino acid derivative of the present invention having a tetrazole ring or a triazole ring is preferably 1 or 2, and more preferably 1.
In the amino acid derivative having a tetrazole ring or a triazole ring, the preferred number of amino groups is 1 or 2, more preferably 1. The amino group is preferably a secondary amino group (that is, a state having one hydrogen atom).

  The amino acid derivative having a tetrazole ring may have other substituents, and the substituent species is not particularly limited. The substituent is preferably on the alkylene chain or at the end of the alkyl group. Examples of the substituent include a halogen atom (a fluorine atom, a chloro atom, a bromine atom, or an iodine atom), an alkyl group (preferably a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms), an alkenyl group (preferably, A substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms), an alkynyl group (preferably a substituted or unsubstituted alkynyl group having 2 to 10 carbon atoms), an aryl group (preferably an aryl group having 6 to 20 carbon atoms). Specifically, for example, phenyl, naphthyl), a heterocyclic group (the hetero atom in the heterocyclic group includes a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a phosphorus atom, etc., preferably 5 or 6 A monovalent group obtained by removing one hydrogen atom from a substituted or unsubstituted aromatic or non-aromatic heterocyclic compound; Preferably a 5- or 6-membered aromatic heterocyclic group having 3 to 20 carbon atoms), an acyl group (preferably a formyl group, a substituted or unsubstituted alkylcarbonyl group having 2 to 10 carbon atoms, such as an acetyl group). An alkoxycarbonyl group (preferably a substituted or unsubstituted alkoxycarbonyl group having 2 to 10 carbon atoms such as methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl, n-octadecyloxycarbonyl), an aryloxycarbonyl group (preferably a carbon A substituted or unsubstituted aryloxycarbonyl group of formula 7 to 21), a heterocyclic oxycarbonyl group (the heterocycle has the same meaning as described above, and the same applies hereinafter unless otherwise specified).

A carbamoyl group (preferably a substituted or unsubstituted carbamoyl having 1 to 10 carbon atoms such as carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N, N-di-n-octylcarbamoyl), N-hydroxycarbamoyl Group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group, carbazoyl group, carboxy group or a salt thereof, oxalyl group, oxamoyl group, cyano group, Carboximidoyl group, formyl group, hydroxy group, alkoxy group (preferably a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms such as methoxy, ethoxy, isopropoxy, t-butoxy, n-octyloxy, 2- Methoxyeth Ii), aryloxy group, heterocyclic oxy group, acyloxy group (preferably formyloxy group, substituted or unsubstituted alkylcarbonyloxy group having 2 to 10 carbon atoms), alkoxycarbonyloxy group (preferably having 2 carbon atoms) 10 substituted or unsubstituted alkoxycarbonyloxy groups such as methoxycarbonyloxy, ethoxycarbonyloxy, t-butoxycarbonyloxy, n-octylcarbonyloxy), aryloxycarbonyloxy groups, carbamoyloxy groups (preferably having 1 to 1 carbon atoms) 10 substituted or unsubstituted carbamoyloxy groups such as N, N-dimethylcarbamoyloxy, N, N-diethylcarbamoyloxy, morpholinocarbonyloxy, N, N-di-n-octylaminocarbonyloxy, -n- octyl carbamoyloxy), a sulfonyloxy group, an amino group, an alkylamino group (preferably a substituted or unsubstituted alkylamino group having 1 to 10 carbon atoms), an arylamino group, heterocyclic amino group,

An acylamino group (preferably a formylamino group, a substituted or unsubstituted alkylcarbonylamino group having 1 to 10 carbon atoms), a sulfonamide group, a ureido group (preferably a substituted or unsubstituted ureido having 1 to 10 carbon atoms, For example, carbamoylamino, Nn, N-dimethylaminocarbonylamino, N, N-diethylaminocarbonylamino, morpholinocarbonylamino), thioureido group, N-hydroxyureido group, alkoxycarbonylamino group (preferably substituted with 2 to 10 carbon atoms or Unsubstituted alkoxycarbonylamino group such as methoxycarbonylamino, ethoxycarbonylamino, t-butoxycarbonylamino, n-octadecyloxycarbonylamino, N-methyl-methoxycarbonylamino), aryl An oxycarbonylamino group, a sulfamoylamino group (preferably a substituted or unsubstituted sulfamoylamino group having 0 to 10 carbon atoms such as sulfamoylamino, N, N-dimethylaminosulfonylamino, Nn- Octylaminosulfonylamino), semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N-alkylsulfonylureido group, N-arylsulfonylureido group, N-acylureido group, N-acylsulfamoylamino Group, hydroxyamino group, nitro group, quaternized heterocyclic group containing a nitrogen atom, isocyano group, imino group, mercapto group, alkylthio group (preferably a substituted or unsubstituted alkylthio group having 1 to 10 carbon atoms) E.g. methylthio, ethylthio n-hexadecylthio), arylthio group, heterocyclic thio group, alkyldithio group, aryldithio group, heterocyclic dithio group, alkylsulfonyl group (preferably a substituted or unsubstituted alkylsulfonyl group having 1 to 10 carbon atoms), aryl A sulfonyl group, an alkylsulfinyl group (preferably a substituted or unsubstituted alkylsulfinyl group having 1 to 10 carbon atoms), an arylsulfinyl group, a sulfo group or a salt thereof, and a sulfamoyl group (preferably a substituted or unsubstituted group having 0 to 10 carbon atoms). Substituted sulfamoyl groups such as N-ethylsulfamoyl, N- (3-dodecyloxypropyl) sulfamoyl, N, N-dimethylsulfamoyl), N-acylsulfamoyl groups, N-sulfonylsulfamoyl groups or Its salt,

A phosphino group (preferably a substituted or unsubstituted phosphino group having 2 to 10 carbon atoms, such as dimethylphosphino, diphenylphosphino, methylphenoxyphosphino), a phosphinyl group (preferably a substituted or unsubstituted group having 2 to 10 carbon atoms). A substituted phosphinyl group such as phosphinyl, dioctyloxyphosphinyl, diethoxyphosphinyl), a phosphinyloxy group (preferably a substituted or unsubstituted phosphinyloxy group having 2 to 10 carbon atoms such as di- Phenoxyphosphinyloxy, dioctyloxyphosphinyloxy), phosphinylamino group (preferably a substituted or unsubstituted phosphinylamino group having 2 to 10 carbon atoms such as dimethoxyphosphinylamino, dimethylaminophosphine Finylamino), silyl group (preferred Or a substituted or unsubstituted silyl group having 3 to 10 carbon atoms (for example, trimethylsilyl, t-butyldimethylsilyl, phenyldimethylsilyl), azide group, azo group, amidino group, aminooxy group, isocyanato group, thioisocyanato group, It represents a cyanato group, a dithiocarboxy group or a salt thereof, a sulfinamoyl group, a sulfino group or a salt thereof, a thiocyanato group, a nitroso group, or a guanidide group. These substituents may be further substituted.

Preferred examples of the substituent include a carboxyl group, a hydroxyl group, a sulfo group, a carbamoyl group, a sulfamoyl group, and an amino group. A carboxyl group and a hydroxyl group are more preferable, and a carboxyl group is most preferable.
However, it is more preferable that the tetrazole ring and the triazole ring have no substituent.

  Of the amino acid derivatives containing a tetrazole ring of the present invention, a compound represented by general formula (I) is preferable, and an amino acid derivative represented by general formula (II) or general formula (III) is more preferable. .

一般式（I）

Formula (I)

In the formula, L ^a and L ^b represent a divalent linking group which may have a substituent. R represents a hydrogen atom or a substituent. Het represents a tetrazole ring or a triazole ring.

L ^a is preferably an alkylene group having 1 to 10 carbon atoms, methylene, ethylene, trimethylene are more preferable, and ethylene is most preferred. These alkylene groups may have a substituent, and examples of the substituent include an alkyl group, a hydroxyl group, a halogen, a hydroxyalkyl, a carboxyalkyl, a sulfoalkyl, and a carbamoylalkyl, preferably an alkyl group, more preferably It is a C1-C10 alkyl group.

L ^b preferably represents an alkylene group having 1 to 10 carbon atoms, more preferably methylene, ethylene or trimethylene, and most preferably methylene. These alkylene groups may have a substituent, and examples of the substituent include an alkyl group, a hydroxy group, a halogen, a hydroxyalkyl, a carboxyalkyl, a sulfoalkyl, and a carbamoylalkyl, preferably an alkyl group, more preferably It is a C1-C10 alkyl group.

R represents a hydrogen atom or a substituent, and the substituent is preferably an alkyl, hydroxyalkyl, cyanoalkyl, carboxyalkyl, sulfoalkyl group or the like. More preferred are hydroxyethyl, cyanoethyl, carboxyethyl and carboxymethyl. However, R is more preferably a hydrogen atom.

一般式（II）

Formula (II)

Wherein, L ^a and R have the same meanings as those of general formula (I), and preferred ranges are also the same. R ^a represents a hydrogen atom or an alkyl group.
R ^a is more preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and examples thereof include methyl, ethyl, propyl and the like. This alkyl group may further have a substituent, and examples of the substituent include a hydroxy group, a carboxy group, a sulfo group, and a carbamoyl group. Preferably, it is a hydroxy group or a carboxy group. However, R ^a is most preferably a hydrogen atom.

Wherein, L ^a and R have the same meanings as those of general formula (I), and preferred ranges are also the same. ^Ra is synonymous with the definition described in general formula (II), and its preferable range is also the same.

Specific examples of the specific amino acid derivative [Exemplary Compound 1 to Exemplified Compound 36] that can be suitably used in the present invention are listed below, but the present invention is not limited thereto.

  As described above, the specific amino acid derivative can be synthesized by a known method. For example, Journal of the American Chemical Society, 72, 2599 (1950), Journal of Heterocyclic Chemistry, 2, 308 (1965), Journal of Medicinal Chemistry, 15, 483 (1972), Journal of the American Chemical Society, 73, 1641 (1951), Journal of General Chemistry of the USSR (English), 55, 10, 2109-2113 (1985).

As an example, the method for synthesizing the exemplified compound 16 will be described in detail below. Other compounds can be synthesized in the same manner.
Intermediate 1 is obtained by the method described in Tetrahedron, 61, (2005) 4983-4987. 10 g (0.102 mol) of intermediate 1, 100 ml of dimethylformamide and 12.4 g (0.122 mol) of triethylamine are placed in a three-necked flask and stirred at an internal temperature of 65 ° C. Thereto, 12.5 g (0.122 mol) of chloroacetic acid ethyl ester is added dropwise over 30 minutes. After concentration with an evaporator, the residue is dissolved in 200 ml of ethyl acetate, washed with dilute hydrochloric acid, and the ethyl acetate layer is dried over magnesium sulfate. The filtrate is concentrated with an evaporator and separated and purified by silica gel column chromatography to obtain Intermediate 2. Dissolve in 100 ml of ethanol, add 5N aqueous sodium hydroxide solution and stir at room temperature. Compound 16 is obtained by neutralizing with hydrochloric acid and then concentrating with an evaporator (Scheme 1).

In the metal polishing slurry of the present invention, the specific amino acid derivative may be used alone or in combination of two or more.
The addition amount of the specific amino acid derivative contained in the metal polishing liquid of the present invention is preferably 0.0005 to 5 mol, more preferably 0.01 to 1 L of the metal polishing liquid used for polishing as a total amount. 0.5 mol.

The metal polishing liquid of the present invention is not particularly limited in its formulation, and does not impair the effects of the present invention, except that it contains at least one of the specific amino acid derivatives, an oxidizing agent, and a solvent / dispersion medium as constituent components. As long as it is possible, a compound used in a known metal polishing liquid can be selected and used according to the purpose.
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.

  Hereinafter, components other than the specific amino acid 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 contains a compound (oxidant) that can oxidize a metal to be polished. Examples of the oxidizing agent include hydrogen peroxide, peroxide, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, persulfate, Examples thereof include dichromate, permanganate, ozone water, silver (II) salt, and 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]
In addition to the specific amino acid derivative, other organic acids can be used 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 more 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, Examples thereof include tartaric acid, citric acid, lactic acid, α-amino acids, and ammonium salts and alkali metal salts thereof. In particular, malic acid, tartaric acid, citric acid, glycine, and glycolic acid 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]
The polishing liquid of the present invention can further contain an inorganic acid. 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 and the like. Among inorganic acids, nitric 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.

[Compound having an aromatic ring]
The metal polishing liquid in the present invention includes a compound having a function as a passive film forming agent that suppresses deterioration of the oxidant, forms a passive film on the metal surface, and controls the polishing rate. Specifically, it may contain a compound having an aromatic ring.
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, and benzotriazole, 4-hydroxybenzotriazole, 4-carboxyl-1H-benzotriazole butyl ester, tolyltriazole, and naphthotriazole. It is done.

[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, the following additives can be used 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 salt etc. can be used .

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 contains 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. 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 the pipe, and the flow of liquid is repeatedly separated and merged. Conventional methods such as a method of providing blades that rotate in the above can be employed.

  The supply rate of the 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 amino acid derivative according to the present invention is preferably added to (B) together with the passive film-forming agent among the two 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.

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)
30% by mass hydrogen peroxide (oxidant) 4 g / L
Exemplary Compound 1 0.1 mol / L
Colloidal silica (abrasive) 8 g / L
Add pure water for a total volume of 1000 mL
pH (adjusted with ammonia water and nitric acid) 7.0

(Polishing test)
Polishing pad: IC1400XY-K Groove (Rodale)
Polishing machine: LGP-612 (LapmaSterSFT)
Holding pressure: 70 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 49 electrical locations on 49 copper or tantalum blanket wafer surfaces.
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.
The depth of the groove between the copper wiring and the barrier layer: The wafer was divided, and the wiring portion was photographed from the side with a scanning electron microscope (SEM), and the depth (d) of the groove was measured (see FIG. 1).
Table 1 below shows the polishing rate, dishing, and depth of the groove between the copper wiring and the barrier layer obtained by performing CMP using the above polishing liquid.

<Examples 2-4 and Comparative Examples 1-2>
Examples 2 to 4 were prepared in the same manner as in Example 1 except that the compound 1 of the present invention in the formulation of the metal polishing liquid 1 in Example 1 was changed to the compounds shown in Table 1. A polishing test was conducted in the same manner as in Example 1. Further, Exemplified Compound 1 which is the compound of the present invention was changed to the compounds shown in Table 1 respectively, and benzotriazole was added in an amount (0.030 mg / L) at which the total performance was optimized (similar to Example 1). Comparative Examples 1 and 2 were prepared, and a polishing test was conducted in the same manner as in Example 1. The results for the metal polishing liquid are also shown in Table 1 below.

  As shown in Table 1, the metal polishing liquid containing the amino acid derivative of the present invention is polishing against a polishing liquid containing an amino acid known to have a high polishing rate such as glycine and iminodiacetic acid. It became clear that the effect of improving the dishing and improving the groove formed between the copper wiring and the barrier layer was excellent without significantly reducing the speed. In addition, it is usually necessary to add an aromatic compound such as benzotriazole that suppresses the deterioration of the oxidizing agent and controls the polishing rate in order to improve the total performance of the polishing agent. The polishing liquid had good polishing rate and dishing performance without adding such a compound.

It is a schematic diagram of a cross section of a wafer in which a groove is formed between a copper wiring and a barrier layer.

Explanation of symbols

1: Copper wiring 2: Barrier layer 3: Insulating layer 4: Groove d: Groove depth

Claims (3)

  A metal polishing liquid used for chemical mechanical planarization of a semiconductor device, comprising an amino acid derivative having at least one tetrazole ring or triazole ring. The metal polishing slurry according to claim 1, wherein the amino acid derivative having at least one tetrazole ring or triazole ring is an amino acid derivative represented by the following general formula (I).
Formula (I)

In the formula, L ^a and L ^b represent a divalent linking group which may have a substituent. R represents a hydrogen atom or a substituent. Het represents a tetrazole ring or a triazole ring.   The metal polishing liquid according to claim 1 or 2, wherein the metal polishing liquid is mainly used for polishing copper wiring in chemical mechanical planarization of a semiconductor device.

Images