JP2007088024A - Polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing method having a high CMP speed at a low flow rate. <P>SOLUTION: In this chemical mechanical polishing method, a polishing solution containing an etching suppressant is supplied to a polishing pad on a polishing plate at a flow rate of 0.35 ml/(min cm<SP>2</SP>) or less per unit area of a semiconductor substrate per unit time. Then, with the polishing pad and a polished surface being in contact with each other, the polishing pad and the polished surface are moved relatively with each other to remove at least part of a metal film. As for the etch suppressant, tetrazoles are preferably used. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to manufacturing of semiconductor devices, and more particularly to a chemical mechanical polishing method in a wiring process of semiconductor devices.

In the development of semiconductor devices typified by large-scale integrated circuits (hereinafter referred to as “LSI”), in recent years, higher density and higher integration have been achieved by miniaturization and stacking of wiring for higher integration and higher speed. Is required. Chemical mechanical polishing (hereinafter referred to as “CMP”) has been used as a technique for this purpose, and this is used for polishing an insulating thin film (such as SiO ₂ ) and a metal thin film used for wiring. This is a method of smoothing the substrate and removing excess metal thin film during wiring formation, and is disclosed in, for example, Patent Document 1.

In many cases, the metal polishing solution used in CMP contains abrasive grains (for example, alumina) and an oxidizing agent (for example, hydrogen peroxide). The basic mechanism is considered to oxidize the metal surface with an oxidizing agent and remove the oxide film with abrasive grains, and is described in Non-Patent Document 1, for example.
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 dish-shaped. In some cases, a phenomenon of bending (dishing), an insulator between metal wirings is polished more than necessary, and a metal surface of the wiring is bent in a dish shape (erosion) may occur.
In addition, in a cleaning process usually performed to remove the polishing liquid remaining on the semiconductor surface after polishing, the cleaning process becomes complicated by using a polishing liquid containing solid abrasive grains. In order to treat (waste liquid), there is a problem in terms of cost, for example, it is necessary to settle and separate solid abrasive grains.

  As one means for solving these problems, for example, a metal surface polishing method using a combination of a polishing solution not containing abrasive grains and dry etching is disclosed in Non-Patent Document 2, and Patent Document 2 discloses hydrogen peroxide. Disclosed is a metal polishing fluid comprising: / malic acid / benzotriazole / ammonium polyacrylate and water. According to these methods, 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. Since CMP proceeds by friction with a polishing pad that is much mechanically softer than that containing conventional solid abrasive grains, the occurrence of scratches is reduced.

  On the other hand, tungsten and aluminum have been widely used for interconnect structures as wiring metals. However, LSIs using copper, which has lower wiring resistance than these metals, have been developed with the aim of achieving higher performance. As a method of wiring this copper, for example, a damascene method described in Patent Document 3 is known. Further, a dual damascene method in which a contact hole and a wiring trench are simultaneously formed in an interlayer insulating film and a metal is embedded in both has been widely used recently. As a target material for copper wiring, a high-purity copper target of five nines or more has been shipped. However, in recent years, with the miniaturization of wiring aiming at further higher density, it has become necessary to improve the conductivity and electronic characteristics of copper wiring, and accordingly, a copper alloy in which a third component is added to high-purity copper is required. It is also beginning to be considered for use. 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 copper alloys, a method described in Patent Document 4 is known. However, the chemical polishing method using only the dissolving action has a problem in its planarity due to the occurrence of dishing or the like, compared with CMP in which the metal film on the convex portion is selectively chemically mechanically polished.
Further, Patent Document 5 discloses a chemical mechanical polishing aqueous dispersion that suppresses deterioration of a polishing pad, but relates to leveling of a polishing surface.
Patent Document 6 discloses a polishing method using benzotriazole or a derivative thereof as an anticorrosive.

US Pat. No. 4,944,836 JP 2001-127019 A JP-A-2-278822 JP 49-122432 A JP 2001-279231 A JP 2002-50595 A Journal of Electrochemical Society, 138, 11 (1991), 3460-3464 Journal of Electrochemical Society; Volume 147, Issue 10 (2000), pages 3907-3913

The present invention has been made in order to advance CMP more rapidly in order to increase the productivity of LSI, and is performed based on the above-described request to increase the polishing rate of wiring using copper metal and copper alloy as a raw material. It has been.
In addition, from the viewpoint of environment and cost, there is a demand for a chemical mechanical polishing method that achieves a high polishing rate with a smaller amount.
An object of the present invention is to provide a polishing method having a rapid CMP rate at a low flow rate.

  As a result of intensive studies, the present inventor has found that the above problems can be solved by the following chemical mechanical polishing method, and has completed the present invention. That is, the present invention is (1) below and is listed together with (2) and (3) which are preferred embodiments.

(1) A polishing liquid containing an etching inhibitor is supplied to a polishing pad on a polishing surface plate at a flow rate of 0.35 ml / (min · cm ² ) or less per unit area and unit time of a semiconductor substrate. And a mechanical mechanical polishing method, wherein at least a part of the metal film is removed by relative movement in a state of contact with
(2) The chemical mechanical polishing method according to (1), wherein the etching inhibitor is a compound represented by the following formula (I):

式中、Ｒ¹及びＲ²は、各々独立に、水素原子又は１価の置換基を表し、Ｒ¹及びＲ²が互いに結合して環を形成してもよい。なお、Ｒ¹及びＲ²が同時に水素原子の場合、式（Ｉ）で表される化合物は、その互変異性体でもよい。
（３）更に酸化剤、及び、有機酸又はアミノ酸を含有する（１）又は（２）に記載の化学的機械的研磨方法。

In the formula, R ¹ and R ² each independently represent a hydrogen atom or a monovalent substituent, and R ¹ and R ² may be bonded to each other to form a ring. When R ¹ and R ² are simultaneously hydrogen atoms, the compound represented by the formula (I) may be a tautomer thereof.
(3) The chemical mechanical polishing method according to (1) or (2), further comprising an oxidizing agent and an organic acid or amino acid.

  High polishing rate in polishing by removing at least part of a metal film made of copper or a copper-based alloy formed on an insulating film by a chemical mechanical polishing method of the present invention even with a small supply amount of polishing liquid Could be maintained.

The polishing method of the present invention will be described below.
The chemical mechanical polishing method of the present invention (hereinafter also simply referred to as “polishing method”) uses a polishing liquid containing an etching inhibitor as a semiconductor substrate unit area and 0.35 ml / (min · cm ² ) or less per unit time. It supplies to the polishing pad on a polishing surface plate with the flow volume of this, and it grind | polishes by making it relatively move in the state which contacted the polishing pad and the to-be-polished surface.
In the polishing method of the present invention, a polishing liquid containing an etching inhibitor is used. Examples of the etching inhibitor include cyclic compounds having four or more nitrogen atoms as a coordination atom in one molecule. Examples of such cyclic compounds include tetrazoles and biimidazoles.
The polishing method of the present invention can remove a part of the copper wiring or the like formed on the insulating film at a high polishing rate even if the supply amount of the polishing liquid is relatively small. Specifically, even when the polishing liquid is supplied at a flow rate of 0.35 ml / (min · cm ² ) or less per unit area and unit time of the semiconductor substrate, the flow rate is further 0.20 ml / (min · cm ² ) or less. A good removal rate (RR: Removing Rate) can be obtained even if it is supplied at a low pressure. The lower limit is preferably about 0.05 ml / (min · cm ² ).
Taking a wafer with a diameter of 200 mm as an example, the above flow rates correspond to about 110 ml / min and about 63 ml / min, respectively.

  The polishing liquid of the present invention preferably contains a tetrazole compound represented by the formula (I).

In the formula, R ¹ and R ² each independently represent a hydrogen atom or a monovalent substituent, and R ¹ and R ² may be bonded to each other to form a ring. When R ¹ and R ² are simultaneously hydrogen atoms, the compound represented by the formula (I) may be a tautomer thereof.

Although monovalent substituent R ¹ and R ² can take is not particularly limited in the formula (I), for example include the following. However, in R ¹ , among the specific examples illustrated below, monovalent substituents that cannot be stably obtained when the compound is bonded to a nitrogen atom are excluded.

  Here, the “substituent” includes a substituent atom. In the examples of groups (atomic groups) in the present invention, in the case of substitutable substituents, groups that are substituted together with unsubstituted groups are also included. For example, the “alkyl group” includes not only an unsubstituted alkyl group but also a substituted alkyl group having at least one substituent.

  Examples of the monovalent substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched or cyclic alkyl group, and a polycyclic group such as a bicycloalkyl group). An alkyl group or an active methine group), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (regarding the position of substitution), an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, hetero Ring oxycarbonyl group, carbamoyl group (which may be a carbamoyl group having a substituent, such as N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfoyl group, Famoylcarbamoyl group), carbazoyl group, carboxy group or its , Oxalyl group, oxamoyl group, cyano group, carbonimidoyl group (Carbonimidoyl group), formyl group, hydroxy group, alkoxy group (including groups containing repeating ethyleneoxy group or propyleneoxy group units), aryloxy group, heterocyclic ring An oxy group, an acyloxy group, an (alkoxy or aryloxy) carbonyloxy group, an (unsubstituted, monosubstituted or disubstituted) carbamoyloxy group, an (alkyl or aryl) sulfonyloxy group,

  Amino group, (alkyl, aryl, or heterocyclic) amino group, acylamino group, sulfonamide group, ureido group, thioureido group, N-hydroxyureido group, imide group, (alkoxy or aryloxy) carbonylamino group, sulfamoyl Amino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfonylureido group, N-acylureido group, N-acylsulfamoylamino group, hydroxyamino group, A nitro group, a heterocyclic group containing a quaternized nitrogen atom (eg, pyridinio group, imidazolio group, quinolinio group, isoquinolinio group), isocyano group, imino group, mercapto group, (alkyl, aryl, or heterocyclic) thio group , (Alki , Aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group or a salt thereof, sulfamoyl group (substituted sulfamoyl group may be used, for example, N-acylsulfur group Moyl group, N-sulfonylsulfamoyl group) or a salt thereof, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, silyl group and the like.

  The active methine group means a methine group substituted with two electron-withdrawing groups. Examples of the electron-withdrawing group include an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, and an alkyl group. A sulfonyl group, an arylsulfonyl group, a sulfamoyl group, a trifluoromethyl group, a cyano group, a nitro group, and a carbonimidoyl group (Carbonimidoyl group) are meant. Two electron withdrawing groups may be bonded to each other to form a cyclic structure. The salt means a cation such as alkali metal, alkaline earth metal or heavy metal, or an organic cation such as ammonium ion or phosphonium ion.

  Among these, preferable monovalent substituents include, for example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched, or cyclic alkyl group, such as a bicycloalkyl group). May be a polycyclic alkyl group or may contain an active methine group), alkenyl group, alkynyl group, aryl group, heterocyclic group (regardless of the position of substitution), acyl group, alkoxycarbonyl group, aryloxycarbonyl Group, heterocyclic oxycarbonyl group, carbamoyl group, N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group, carbazoyl group, Oxalyl group, oxamoyl group, cyano group, carvone Midyl group (Carbonimidoyl group), formyl group, hydroxy group, alkoxy group (including groups containing ethyleneoxy group or propyleneoxy group units), aryloxy group, heterocyclic oxy group, acyloxy group, (alkoxy or aryloxy) A carbonyloxy group, a carbamoyloxy group, a sulfonyloxy group, an (alkyl, aryl, or heterocyclic) amino group, an acylamino group, a sulfonamide group, a ureido group, a thioureido group, an N-hydroxyureido group, an imide group,

(Alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfonylureido group, N-acylureido group, N-acylsulfamoylamino group, hydroxyamino group, nitro group, quaternized heterocyclic group containing nitrogen atom (for example, pyridinio group, imidazolio group, quinolinio group, isoquinolinio group), isocyano group, imino group, mercapto Group, (alkyl, aryl, or heterocyclic) thio group, (alkyl, aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group or a salt thereof, sulfamoy Group, N- acylsulfamoyl group, N- sulfonylsulfamoyl group or a salt thereof, a phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, and a silyl group.

  More preferable monovalent substituents are, for example, a halogen atom (fluorine atom, chlorine atom, bromine atom, or iodine atom), an alkyl group (straight chain, branched or cyclic alkyl group), and a polycyclic group such as a bicycloalkyl group. An alkyl group or an active methine group), an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group (regarding the position of substitution).

The ring formed by combining R ¹ and R ² together with the —C—N— bond in formula (I) may be monocyclic or polycyclic, preferably a 5- to 6-membered ring. Or a polycyclic ring composed of a 5- to 6-membered ring.

  The above monovalent substituent may be further substituted with any substituent selected from the exemplified substituent group.

  The molecular weight of the compound represented by the formula (I) is preferably 20 to 600, more preferably 40 to 400.

  Specific examples of the compound represented by the formula (I) are shown below, but are not limited thereto.

Among the compounds represented by formula (I), preferred are compounds I-1, I-3, I-4, I-10, I-15, I-21, I-22, I-23, Examples thereof include I-41 and I-48, and compounds I-1, I-4, I-15, I-22 and I-23 are more preferable.
Moreover, the compound represented by Formula (I) may be used independently, and may be used together 2 or more types.

  The compound represented by the formula (I) can be synthesized according to a conventional method, or a commercially available product may be used.

  The added amount of the compound represented by the formula (I) means, as a total amount, a metal polishing liquid used for polishing (that is, a diluted metal polishing liquid when diluted with water or an aqueous solution. In 1 L of “a metal-polishing liquid for use in polishing” is preferably 0.0001 to 1.0 mol, more preferably 0.001 to 0.5 mol, and still more preferably 0.01. ~ 0.1 mol. That is, the addition amount of the compound represented by the formula (I) is 1.0 mol or less in 1 L of the metal polishing liquid from the viewpoint of preventing the deterioration (ineffectiveness and decomposition) of the oxidant and the compound represented by the formula (I). Is preferable, and 0.0001 mol or more is preferable for obtaining a sufficient effect.

A thiocyanate, a thioether, a thiosulfate, or a mesoionic compound may be used in combination in an amount less than the amount of the compound represented by formula (I).
As the thiocyanate used in the present invention, the thiocyanate described in JP-A No. 2004-235319 can be preferably mentioned, and as the thioether, the thioether described in JP-A No. 2004-235318 is preferably mentioned. As the thiosulfate, the thiosulfate described in JP-A No. 2004-235326 can be preferably mentioned, and as the meso ion compound, the meso-ion compound described in JP-A No. 2004-235320 is preferably mentioned. be able to.

The metal polishing slurry of the present invention contains at least the compound represented by formula (I) as a constituent component, preferably further contains an oxidizing agent, and is usually an aqueous solution, more preferably from an organic acid and an amino acid. Containing at least one selected from the group consisting of:
The metal polishing slurry of the present invention may further contain other components, and preferred components include surfactants, water-soluble polymers, and additives.
Each component contained in the metal polishing slurry may be used alone or in combination of two or more.

Of the components added during the preparation of the metal polishing liquid concentrate, the blending amount of water having a solubility in water at room temperature of less than 5% is preferably within twice the solubility in water at room temperature. More preferably, it is within 5 times. When this addition amount exceeds twice, it becomes difficult to prevent precipitation when the concentrate is cooled to 5 ° C.
In this specification, “concentration” and “concentrated liquid” are conventional expressions meaning “thick” and “thick liquid” rather than polishing liquid in a state used for CMP, and are physical expressions such as evaporation. It is used in a different way from the meaning of general terms that accompany the concentration operation.

That is, 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 when used for polishing, water or an aqueous solution is used. It is diluted and used for polishing. The dilution factor is generally 1 to 20 volume times.
In the present invention, the “metal polishing liquid” means 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.

(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, Bichromate, 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) ethylenedia Min-N, N-diacetic acid and the like 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 them, hydrogen peroxide, iodate, hypochlorite, chlorate, and an organic complex salt of iron (III) are preferable, and a preferable complex-forming compound in the case of using an organic complex salt of iron (III) is citric acid, Tartaric acid, aminopolycarboxylic acid (specifically, ethylenediamine-N, N, N ′, N′-tetraacetic acid, diethylenetriaminepentaacetic acid, 1,3-diaminopropane-N, N, N ′, N′-tetraacetic acid , Ethylenediamine-N, N′-disuccinic acid (racemic), ethylenediamine disuccinic acid (SS), N- (2-carboxylateethyl) -L-aspartic acid, N- (carboxymethyl) -L-aspartic acid , Β-alanine diacetate, methyliminodiacetic acid, nitrilotriacetic acid, iminodiacetic acid).
Among the oxidizing agents, hydrogen peroxide and iron (III) ethylenediamine-N, N, N ′, N′-tetraacetic acid, 1,3-diaminopropane-N, N, N ′, N′-tetraacetic acid and ethylenediaminedi A succinic acid (SS body) complex is most 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.

(acid)
The metal polishing slurry of the present invention preferably further contains an acid. The acid here means a compound having a structure different from that of an oxidizing agent for oxidizing a metal, and within this range, an inorganic acid, an organic acid, and an amino acid can be mentioned.
Examples of the inorganic acid include sulfuric acid, nitric acid, boric acid, phosphoric acid, etc. Among the inorganic acids, phosphoric acid is preferable.
In the present invention, organic acids and amino acids are particularly preferably present, and amino acids are more preferable.
The organic acid is preferably water-soluble. What was chosen from the group illustrated below is more preferable. 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, and salts thereof such as ammonium salt and alkali metal salt, sulfuric acid, nitric acid, ammonia, ammonium salts, or a mixture thereof. Among these, formic acid, malonic acid, malic acid, tartaric acid, and citric acid are particularly preferable for a laminated film including at least one metal layer selected from copper, copper alloys, and copper or copper alloy oxides.

The amino acid is preferably water-soluble, and more preferably a compound selected from the following group.
Glycine, L-alanine, β-alanine, L-2-aminobutyric acid, L-norvaline, L-valine, L-leucine, L-norleucine, L-isoleucine, L-alloisoleucine, L-phenylalanine, L-proline, Sarcosine, L-ornithine, L-lysine, taurine, L-serine, L-threonine, L-allothreonine, L-homoserine, L-tyrosine, 3,5-diiodo-L-tyrosine, β- (3,4- Dihydroxyphenyl) -L-alanine, L-thyroxine,

4-hydroxy-L-proline, L-cystine, L-methionine, L-ethionine, L-lanthionine, L-cystathionine, L-cystine, L-cysteic acid, L-aspartic acid, L-glutamic acid, S- (carboxy Methyl) -L-cysteine, 4-aminobutyric acid, L-asparagine, L-glutamine, azaserine, L-arginine, L-canavanine, L-citrulline, δ-hydroxy-L-lysine, creatine, L-quinurenin, L- Amino acids such as histidine, 1-methyl-L-histidine, 3-methyl-L-histidine, ergothioneine, L-tryptophan, actinomycin C1, apamin, angiotensin I, angiotensin II and antipine.
Malic acid, tartaric acid, citric acid, glycine, and glycolic acid are particularly preferable in that the etching rate can be effectively suppressed while maintaining a practical CMP rate.

  The addition amount of an acid such as an organic acid and / or an amino acid is preferably 0.0005 to 0.5 mol, preferably 0.005 mol to 0.3 mol, in 1 L of a metal polishing liquid used for polishing. Is more preferable, and 0.01 mol to 0.1 mol is particularly preferable. 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.

(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 Le) ethylenediamine -N, N'-diacetic acid, 1,2-dihydroxy-4,6-disulfonic acid.

The chelating agent may be used alone or in combination of two or more as required.
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 also 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 Azoles such as -1-methyl) -N- (1,2,4-triazolyl-1-methyl) -2-ethylhexylamine, tolyltriazole, naphthotriazole, bis [(1-benzotriazolyl) methyl] phosphonic acid ; Mercaptans such as nonyl mercaptan, dodecyl mercaptan, triazine thiol, triazine dithiol, triazine trithiol, and others, anthranilic acid, aminotoluic acid, quinaldic acid and the like. Among these, the combined use of chitosan, ethylenediaminetetraacetic acid, L-tryptophan, cuperazone, triazinedithiol, benzotriazole, 4-hydroxybenzotriazole, 4-carboxyl-1H-benzotriazole butyl ester, tolyltriazole, and naphthotriazole is preferable.

  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, polyammonium methacrylate, polymethacrylic acid sodium salt, polyamic acid, polymaleic acid, polyitaconic acid, polyfumaric acid, poly (p-styrenecarboxylic acid), polyacrylic acid, polyacrylamide, aminopolyacrylamide, polyacrylic Ammonium acid salt, polyacrylic acid sodium salt, polyamic acid, polyamic acid ammonium salt, polyamic acid sodium salt and polyglyoxylic acid and salts thereof; vinyl polymers such as polyvinyl alcohol, polyvinylpyrrolidone and polyacrolein; methyl Tauric acid ammonium salt, methyl tauric acid sodium salt, methyl sodium sulfate salt, ethylammonium sulfate salt, butylammonium sulfate salt, vinylsulfonic acid sodium salt, 1-a Sulfonic acid sodium salt, 2-allylsulfonic acid sodium salt, methoxymethylsulfonic acid sodium salt, ethoxymethylsulfonic acid ammonium salt, 3-ethoxypropylsulfonic acid sodium salt, methoxymethylsulfonic acid sodium salt, ethoxymethylsulfonic acid ammonium salt, Examples include sulfonic acids such as 3-ethoxypropylsulfonic acid sodium salt and sulfosuccinic acid sodium salt; and amides such as propionamide, acrylamide, methylurea, nicotinamide, succinic acid amide, and sulfanilamide.

  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, 500-100,000 are preferable, and 2,000-50,000 are especially preferable.

[Alkaline / Acid]
The metal polishing slurry of the present invention preferably contains an alkali agent and / or an acid agent, and further contains a buffering agent as necessary.
Here, the alkali agent and / or the acid agent is added so that the pH of the metal polishing liquid is set to a predetermined pH as described later.

  Alkaline agents (and buffering agents) include non-metallic alkaline agents such as organic ammonium hydroxides such as ammonium hydroxide and tetramethylammonium hydroxide, alkanolamines such as diethanolamine, triethanolamine and triisopropanolamine, Alkali metal hydroxide such as sodium hydroxide, potassium hydroxide, 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, trishydroxyamino Use methane salt, lysine salt, etc. Kill.

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.

  Examples of acid agents include 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, acetic acid, Preferred examples include organic acids such as lactic acid and inorganic acids such as nitric acid, sulfuric acid and phosphoric acid.

The addition amount of the alkali agent and / or the acid agent may be an amount that maintains the pH within a preferable range, and is 0.0001 mol to 1.0 mol in 1 L of the metal polishing slurry used for polishing. It is preferably 0.003 mol to 0.5 mol, and more preferably.
2-14 are preferable and, as for pH of the metal polishing liquid at the time of using for grinding | polishing, 3-12 are especially preferable. 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.
As addition amount of an abrasive grain, it is preferable that an abrasive grain is 0.01-20 weight% with respect to the total weight of the metal polishing liquid at the time of use, and is the range of 0.05-5 weight%. It is more preferable. In order to obtain a sufficient effect, 0.01% by weight or more is preferable. Since the polishing rate by CMP is saturated, 20% by weight or less is preferable.
The average grain size of the abrasive grains is preferably 5 to 1000 nm, and particularly preferably 10 to 200 nm.

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

[Wiring thickness]
In the present invention, when the LSI to be polished is, for example, a DRAM device system, the wiring half pitch is preferably 0.15 μm or less, more preferably 0.10 μm or less, and particularly preferably 0.08 μm or less. On the other hand, in the MPU device system, the wiring half pitch is preferably 0.12 μm or less, more preferably 0.09 μm or less, and particularly preferably 0.07 μm or less. The polishing liquid of the present invention exhibits particularly excellent effects on these LSIs.

[Barrier metal]
In the semiconductor device to which the polishing method of the present invention is applied, a barrier layer for preventing diffusion of copper is provided between the wiring in which the semiconductor is made of copper metal and / or an alloy containing copper as a main component and the interlayer insulating film. It is preferable. 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.
As the interlayer insulating film, a thin film of an insulating material having a low dielectric constant is preferable, and a preferable insulating material is a material having a relative dielectric constant of 3.0 or less, more preferably a material having a dielectric constant of 2.8 or less. . Specific examples of preferable low dielectric constant materials include BlackDiamond (Applied Materials), FLARE (Honeywell Electronic Materials), SILK (Dow Chemical), CORAL (Novellus System), LKD (JSR) And HSG (manufactured by Hitachi Chemical Co., Ltd.).

The polishing method of the present invention can be preferably applied to a copper (alloy) wiring process by a (dual) damascene method. The method of the present invention can be particularly preferably used in the dual damascene method in which copper (alloy) having a low electrical resistance is used for the wiring metal and a low dielectric constant (low-k) material is introduced for the interlayer insulating film.
As described above, the polishing method of the present invention can be suitably used for planarizing a surface including a metal wiring formed on an insulating film in a semiconductor device such as an LSI. Then, a part of the barrier metal film or the insulating film may be polished.

(Average relative speed)
In the polishing method of the present invention, the average relative motion speed (average relative speed) between the polishing surface of the polishing pad and the surface to be polished is the average value of the relative motion speed in the radial direction of a straight line passing through the center of the surface to be polished. .
For example, when both the surface to be polished and the polishing surface are rotating bodies, the distance between the respective rotation centers is set as the center-to-center distance L. The relative motion speed of the surface to be polished on the line connecting the centers is obtained and used as the average relative speed.
In the present invention, the average relative speed is preferably 0.5 to 5.0 m / s, more preferably 1.0 to 3.5 m / s, and 1.5 to 3.0 m / s. It is particularly preferred.

(Contact pressure)
In the present invention, a value obtained by dividing the force applied to the contact portion between the polishing surface and the surface to be polished by the contact area is defined as the contact pressure. For example, when the entire surface to be polished having a diameter of φ200 mm is pressed against a polished surface having a diameter of φ600 mm with a force of 400 N, the contact area is (0.1) ² π = 3.14 · 10 ⁻² m ^2. The pressure is 400 / (3.14 · 10 ⁻² ) = 12,732 Pa.
The contact pressure applied to the CMP method of the present invention is preferably 1,000 to 25,000 Pa, more preferably 2,000 to 17,500 Pa, and 3,500 to 14,000 Pa. Is more 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 .

  The apparatus that can use the polishing method of the present invention is not particularly limited. For example, Mirra Mesa CMP, Reflexion CMP (manufactured by Applied Materials), FREX200, FREX300 (manufactured by Ebara Corporation), NPS3301, NPS2301 (Nikon), A-FP-310A, A-FP-210A (Tokyo Seimitsu Co., Ltd.), 2300TERES (Lamb Research), Momentum (SpeedFam-IPEC) can be cited as preferred examples. .

  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.

  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.

  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, 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>
The polishing liquid shown below was prepared, and the polishing test was conducted and evaluated.
(Preparation of polishing liquid)
Compound (I-1) (also indicated as Tetrazole) 0.06 g / L
Hydrogen peroxide (oxidant) 3g / L
Glycine (acid) 10g / L
Colloidal silica (average particle size 40nm) 10g / L
Add pure water, total volume 1000mL
pH (adjusted with aqueous ammonia and sulfuric acid) 7.0

(Polishing test)
Substrate: A silicon oxide film is formed on silicon by a reactive ion etching process, a Ta film having a thickness of 20 nm is further formed by a sputtering method, and then a copper film having a thickness of 50 nm is formed by a sputtering method. Polishing pad using an 8-inch diameter wafer in which a copper film having a total thickness of 1000 nm is formed by a plating method: IC1400K-Groove (Rodale)
Polishing machine: LGP-612 (LapmaSter FT)
Holding pressure: 240 g / cm ²
Polishing liquid supply rate (SFR): 200, 100 or 50 ml / min
Corresponding to 0.64, 0.32 and 0.16 ml / (min · cm ² ), respectively, Rotation speed of polishing pad / wafer: 95/95 rpm

(Evaluation methods)
CMP rate: The average polishing rate was determined by converting the film thickness of the metal film before and after CMP from the electrical resistance value at 49 locations on the wafer surface.
Table 1 shows the polishing rate (RR) obtained by performing CMP using the above polishing liquid.

<Example 2 and Comparative Examples 1-3>
In the same manner as in Example 1, using the compounds shown in Table 1, polishing liquids of Example 2 and Comparative Examples 1 to 3 were prepared and subjected to a polishing test. BTA is an abbreviation for benzotriazole, and Bicine is an abbreviation for N, N-Bis (2-hydroxyethyl) glycine.
The obtained results are summarized in Table 1.

As shown in Table 1, the polishing liquid containing the inhibitor, particularly preferably the polishing liquid containing the compound represented by the formula (I), has a low polishing liquid flow rate (0) relative to the polishing liquid containing benzotriazole. .32 and 0.16 ml / (min · cm ² )) were found to show a high polishing rate.

Claims (3)

Supplying a polishing liquid containing an etching inhibitor to a polishing pad on a polishing surface plate at a flow rate of 0.35 ml / (min · cm ² ) or less per unit area and unit time of a semiconductor substrate;
A chemical-mechanical polishing method comprising polishing by relatively moving a polishing pad and a surface to be polished in contact with each other. 2. The chemical mechanical polishing method according to claim 1, wherein the etching inhibitor is a compound represented by the following formula (I).

In the formula, R ₁ and R ₂ each independently represent a hydrogen atom or a monovalent substituent, and R ₁ and R ₂ may be bonded to each other to form a ring. When R ₁ and R ₂ are simultaneously hydrogen atoms, the compound represented by the formula (I) may be a tautomer thereof. The chemical mechanical polishing method according to claim 1 or 2, further comprising an oxidizing agent and an organic acid or amino acid.