TWI485761B - Polishing liquid and polishing method - Google Patents

Description

Grinding liquid and grinding method

The present invention relates to a polishing liquid and a polishing method for use in a process of a semiconductor integrated circuit, and more particularly to a polishing liquid and a polishing method for chemical mechanical polishing in planarization of a wiring step of a semiconductor integrated circuit.

In the development of semiconductor components typified by semiconductor integrated circuits (hereinafter referred to as LSI), in order to achieve miniaturization. High speed, high density. The advancement of high integration. Therefore, in recent years, the demand for miniaturization and stratification of wiring has become higher and higher.

In the case of manufacturing a semiconductor integrated circuit such as an LSI, a plurality of fine wirings are formed, and when metal wiring such as Cu is formed in each layer, a barrier metal such as Ta, TaN, Ti, or TiN is generally formed in advance. The barrier layer is provided to prevent the wiring material from diffusing to the interlayer insulating film (hereinafter referred to as "insulating layer") or to improve the adhesion of the wiring material.

Among the formation of the metal wiring, various techniques such as chemical mechanical polishing (hereinafter referred to as "CMP") are used.

This CMP is a technique necessary for planarizing the surface of an insulating layer or the like, forming a plug, and forming a buried metal wiring. The smoothing of the substrate, the removal of the excess metal film during the formation of the wiring, and the removal of the excess barrier layer are performed by CMP.

The polishing slurry for metal used in CMP generally contains cerium particles (for example, alumina, vermiculite) and an oxidizing agent (for example, hydrogen peroxide, persulfuric acid). Basically, the mechanism should be that the metal surface is oxidized by the oxidant, and the oxide film is removed by the granules. Grinding.

The general method of CMP is to attach a polishing pad to a circular polishing platform (Platen), to infiltrate the surface of the polishing pad with a polishing liquid, and press the surface of the substrate (wafer) against the polishing pad to apply a specific pressure (grinding pressure) from the back surface. In this state, both the polishing table and the substrate are rotated, and the surface of the substrate is planarized by the generated mechanical friction.

In order to form each wiring layer, polishing is generally performed in two stages.

In the first stage of polishing, the excess metal wiring material formed by plating or the like is removed by CMP. Hereinafter, the metal film removing step of the excess metal wiring material is referred to as "metal film CMP". The metal film CMP is applied in one stage or in multiple stages.

In the second stage of polishing, the barrier metal exposed by the first-stage polishing to expose the surface is removed by CMP, and the surface of the insulating layer or the like is planarized. Hereinafter, this polishing step is referred to as "barrier metal CMP". The barrier metal CMP is applied in one stage or in multiple stages.

That is, the barrier metal CMP mainly polishes the metal wiring material and the barrier metal at the same time to planarize the surface.

At this time, when the barrier metal CMP is used using the polishing liquid containing solid cerium particles, the wiring portion is rapidly polished, and dents and erosion occur.

Therefore, in the barrier metal CMP, the polishing rate of the metal wiring portion and the polishing rate of the barrier metal portion are adjusted to finally form a wiring layer having a small drop such as depression or erosion.

That is, it is expected that the polishing rate of the insulating layer can be increased without causing depression or erosion to approximately equal to the polishing rate of the metal wiring member.

In addition, there are other problems as follows: the use of grinding containing solid niobium After the polishing, in order to remove the polishing liquid remaining on the semiconductor surface, the cleaning step which is usually performed is complicated, and in order to treat the washed liquid (waste liquid), it is necessary to sediment and separate the solid cerium particles, which is costly.

As for such a polishing liquid containing solid cerium particles, the following various investigations have been made.

For example, a CMP abrasive and a polishing method (see, for example, Patent Document 1), which have high-speed polishing and no polishing damage, and a polishing composition and a polishing method for improving the cleaning property of CMP (refer to, for example, Patent Document 2), A proposal for a polishing composition for preventing agglomeration of abrasive grains (refer to, for example, Patent Document 3).

However, in the current state, although the above-mentioned polishing liquid is used, a technique for sufficiently suppressing the occurrence of dents and erosion at the time of polishing the barrier layer is not available.

Japanese Patent Laid-Open Publication No. 2003-142432

An object of the present invention is to provide a polishing liquid containing solid cerium particles for chemical mechanical polishing in a planarization step of a semiconductor integrated circuit having a barrier layer, and a polishing liquid and a polishing method capable of suppressing occurrence of dents and erosion.

The inventors of the present invention conducted intensive studies and found that the problem can be solved by using the following polishing liquid.

The polishing liquid of the present invention is used for a semiconductor integrated circuit having a barrier layer The chemical mechanical polishing slurry in the planarization step is characterized by containing (A) colloidal vermiculite particles, (B) a hydrophilic benzotriazole derivative, and (C) a hydrophobic benzotriazole derivative. And (D) an oxidizing agent.

The (B) hydrophilic benzotriazole derivative preferably has a hydroxyl group, an amine group, a carboxyl group or a sulfonic acid group.

The (C) hydrophobic benzotriazole derivative is an carbonyl group having an unsubstituted alkyl group, an alkoxy group having 10 or more carbon atoms, an alkoxycarbonyl group having 15 or more carbon atoms, and 15 or more carbon atoms. An amine group or an amine carbonyl group having 15 or more carbon atoms is suitable.

The polishing liquid of the present invention preferably contains an amino acid, and the water-soluble polymer is also in a suitable state.

In the present invention, the total concentration of the (B) hydrophilic benzotriazole derivative and the (C) hydrophobic benzotriazole derivative is preferably 0.005% by mass or more and 5% by mass or less.

The content ratio of the (B) hydrophilic benzotriazole derivative to the (C) hydrophobic benzotriazole derivative is suitably in a mass ratio of 2:1 to 1:5.

The polishing liquid of the present invention preferably has a pH of 2 to 5.

The polishing method of the present invention uses a polishing liquid containing (A) colloidal vermiculite particles, (B) a hydrophilic benzotriazole derivative, (C) a hydrophobic benzotriazole derivative, and (D) an oxidizing agent. A method of polishing a semiconductor integrated circuit having a barrier layer by chemical mechanical polishing.

The polishing method of the present invention is applicable to the polishing of any barrier layer, preferably the polishing of the barrier layer formed of Mn, Ti, Ru or the like; in such a barrier layer, the invention may also It works.

According to the present invention, in the planarization step of the semiconductor integrated circuit having the barrier layer, the polishing liquid using the solid particles for chemical mechanical polishing can suppress the dishing and etching of the polishing liquid and the polishing method.

The specific aspects of the invention are described below.

The polishing liquid of the present invention is a polishing liquid for chemically mechanically polishing a barrier layer of a semiconductor integrated circuit, which comprises (A) colloidal vermiculite particles, (B) a hydrophilic benzotriazole derivative, ( C) a hydrophobic benzotriazole derivative and (D) an oxidizing agent, optionally containing any component. The components contained in the polishing liquid of the present invention may be used alone or in combination of two or more.

Hereinafter, (B) "hydrophilic benzotriazole derivative" is a "hydrophilic benzotriazole derivative" or a "hydrophilic BTA derivative". (C) "Hydrophobic benzotriazole derivative" is also referred to as "hydrophobic benzotriazole derivative" or "hydrophobic BTA derivative".

In the present invention, the "polishing liquid" refers not only to the polishing liquid used in the polishing (that is, the polishing liquid which is diluted if necessary), but also to the concentrated liquid of the polishing liquid.

The concentrate or the concentrated slurry means that the concentration of the solute is higher than that of the slurry used in the polishing; and when it is used for polishing, it is diluted with water or an aqueous solution or the like, and is used for the abrasive. The dilution ratio is generally 1 to 20 times the volume. In the present specification, "concentration" and "concentrate" are used to refer to the "concentrated" and "concentrated liquid" in the use state, and their usage is different from the general term accompanying physical concentration operations such as evaporation.

The components constituting the polishing liquid of the present invention will be described in detail below.

(A) Colloidal vermiculite particles

The polishing liquid used in the present invention contains colloidal vermiculite particles as a constituent component. The colloidal vermiculite particles are used as abrasive particles (granules).

The colloidal vermiculite particles can be produced by a sol-gel method such as Si(OC ₂ H ₅ ) ₄ , Si(sec-OC ₄ H ₉ ) ₄ , Si(OCH ₃ ) ₄ , Si(OC ₄ H ₉ ). hydrolysis of silicon oxide ₄ and the like alkoxy compounds. The particle size distribution of the first and second colloidal particles (for example, the first and second colloidal vermiculite particles) is extremely sharp.

The average particle diameter of the colloidal vermiculite particles contained is preferably 5 to 60 nm, more preferably 5 to 30 nm, and particularly preferably 20 to 50 nm. In order to achieve a sufficient polishing speed, particles of 5 nm or more are preferred. In order to prevent excessive frictional heat during the polishing process, the particle diameter is preferably 60 nm or less.

Here, the average particle diameter refers to the average particle diameter of the particles used before polishing in a state where the slurry is mixed in a slurry form. The physical properties of the colloidal vermiculite particles are such that the average particle diameter of the colloidal vermiculite particles before the blending is approximately the same as the average particle diameter of the particles present in the polishing liquid, and the average particle diameter in the state before the blending can be measured as The average particle size of the particles in the slurry.

The particle size of the colloidal vermiculite particles is a measured value of the minimum constituent particle diameter of one particle when the abrasive particles are observed by SEM (scanning electron microscope).

The colloidal vermiculite particles to be used may be used alone or in combination of two or more. When used in combination, it is preferred to use two or more kinds of colloidal particles having different particle diameters or shapes from the viewpoint of achieving high polishing rate.

Combinations of different particle sizes, such as large particle size vermiculite with an average particle diameter of 30 to 100 nm and small particle size vermiculite with an average particle diameter of 20 to 60 nm, can be used in combination with a mass ratio of 1:10 to 10:1. The grinding speed of various types of membranes.

Particles with different shapes, such as spherical vermiculite near the true sphere, and non-true spherical particles, 茧-shaped vermiculite particles with a ratio of long diameter to short diameter (long diameter/short diameter) of 1.2 to 5.0, in mass ratio 1 : 10~10:1 can be used together to improve the grinding speed of the insulating film.

Specifically, for example, a combination of spherical vermiculite fine particles having an average particle diameter of about 10 to 50 nm and non-true spherical vermiculite fine particles having a long diameter/minor diameter ratio of 1 to 5 and a long diameter of 50 nm may be used.

Such non-true spherical colloidal vermiculite particles are described in detail in Japanese Patent Application No. 2005-366712, and the description is also applicable to the present application.

The concentration of the abrasive particles containing the colloidal vermiculite particles is preferably 0.5 to 15% by mass based on the total amount of the polishing liquid in use, and more preferably 1 to 10% by mass. In this range, a sufficient polishing processing speed can be obtained, and the generation of excessive friction heat in the polishing processing can be suppressed, which is preferable.

The abrasive particles (granules) may also contain colloidal vermiculite particles, such as smoky quartz, cerium oxide, aluminum oxide, titanium oxide, and the like. However, in this case, the content ratio of the (A) colloidal vermiculite particles in all the granules is 50% by mass or more, and more preferably 80% by mass or more. The contained granules may also be all (A) colloidal gangue particles.

<benzotriazole derivative> In the present invention, (B) a hydrophilic benzotriazole derivative and (C) a hydrophobic benzotriazole derivative are so-called corrosion inhibitors which are adsorbed on a surface to be polished to form a film to control corrosion of the metal surface.

In the present invention, Ewing uses (B) a hydrophilic benzotriazole derivative and (C) a hydrophobic benzotriazole derivative to obtain a good drop characteristic. The mechanism is still unclear, but it should be due to the synergy of each benzotriazole with the progress of the drop. The drop is not expanded. More specifically, it is expected that the hydrophilic benzotriazole and the hydrophobic benzotriazole have different ease of adsorption and corrosion inhibition ability in the uneven portion. It is speculated that due to this mechanism, the occurrence of depression and erosion is suppressed. The invention is not limited to this speculation.

(B) Hydrophilic benzotriazole derivatives

The (B) hydrophilic benzotriazole derivative of the present invention is hydrophilic, that is, without any particular limitation, and preferably has one or more hydrophilic groups as a substituent.

The hydrophilic benzotriazole system of the present invention is defined as those which can dissolve 2 g or more in 100 g of water at room temperature (25 ° C).

The hydrophilic group of the hydrophilic benzotriazole derivative is an amine methyl sulfonyl group, an oxazolyl group, a carboxyl group, a oxalyl group, a sulfhydryl sulfhydryl group, a cyano group, an iminyi group, a decyl group, a hydroxy group. , alkoxy, aryloxy, amine, (alkyl, aryl or heterocyclic) amine, guanylamino, sulfonylamino, ureido, thioureido, quinone imine, (alkoxy or Aromatic oxy)carbonylamine, amidoxime, hemocyanyl, thiosuccinyl, fluorenyl, ammonium, oxalylamine, nitro, heterocyclic group containing a quaternized nitrogen atom (eg, pyridinyl, imidazolyl, quinolinyl, isoquinolinyl), isocyano, imido, fluorenyl, (alkyl, aryl or heterocyclic) thio, (alkyl, aromatic) Or heterocyclic)dithio, (alkyl or aryl)sulfonyl, (alkyl or aryl) sulfinyl, sulfonate, amidoxime, phosphino, phosphino, phosphine The oxy group, the phosphonium amino group, the decylalkyl group and the like are preferred, and the hydroxyl group, the amine group, the carboxyl group and the sulfonic acid group are more preferred, and the hydroxyl group, the amine group and the carboxyl group are particularly preferred.

The amine group of the hydrophilic group may be an amine group of any of the first, second and third stages, and a primary or secondary amine group is preferred from the viewpoint of obtaining sufficient inhibition ability, and the first stage is particularly preferred.

From the viewpoint of obtaining sufficient suppressing ability, the number of hydrophilic groups of the hydrophilic benzotriazole derivative is preferably 1 to 3, more preferably 1 or 2.

The position of the hydrophilic benzotriazole derivative substituted with a hydrophilic group is not specific, and when the number of the hydrophilic groups is 3, the hydrophilic group at the 1st, 3rd, and 4th positions is preferred, and hydrophilicity is preferred. When the number of the base is 2, the hydrophilic group is preferably a 1-position or a 3-position or a 3-position or a 4-position. When the number of the hydrophilic groups is 1, the hydrophilic group at the 1-position or the 3-position is preferred.

(B) a hydrophilic benzotriazole derivative is specifically exemplified below, and the present invention is not limited to these.

The amount of the hydrophilic benzotriazole derivative to be added is preferably 0.0001% by mass or more and 3% by mass or less, and 0.005% by mass or more based on the mass of the polishing liquid used for polishing. And 1% by mass or less is more preferable.

(C) Hydrophobic benzotriazole derivatives

The hydrophobic benzotriazole derivative is hydrophobic, that is, without any particular limitation, and contains an unsubstituted benzotriazole, but has the following substituents. Benzotriazole is preferred.

The hydrophobic benzotriazole system of the present invention is defined as those which can be dissolved in water of 100 ml at room temperature (25 ° C) to less than 2 g.

The substituent in the hydrophobic benzotriazole derivative is an unsubstituted alkyl group, an alkoxy group having 10 or more carbon atoms, an alkoxycarbonyl group having 15 or more carbon atoms, and a carbonyl hydrazine group having 15 or more carbon atoms. Or an amine carbonyl group, an alkenyl group, a cycloalkyl group or an aryl group having 15 or more carbon atoms, an unsubstituted alkyl group, an alkoxy group having 10 or more carbon atoms, an alkoxycarbonyl group having 15 or more carbon atoms, or a carbon atom. 15 or more of a carbonyl hydrazine group or an amine carbonyl group having 15 or more carbon atoms, a cycloalkyl group, an aryl group, an unsubstituted alkyl group, an alkoxy group having 10 or more carbon atoms, and an alkane having 15 or more carbon atoms. An oxycarbonyl group, a carbonyl hydrazine group having 15 or more carbon atoms or an amine carbonyl group having 15 or more carbon atoms is particularly preferable.

The unsubstituted alkyl group of the hydrophobic benzotriazole derivative may be any of a straight chain, a branched chain, and a cyclic group, and a linear alkyl group is preferred.

The unsubstituted alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and particularly preferably an alkyl group having 1 to 3 carbon atoms.

The alkoxy group having 10 or more carbon atoms in the hydrophobic benzotriazole derivative is preferably an alkoxy group having 10 to 30 carbon atoms, more preferably an alkoxy group having 10 to 20 carbon atoms.

The alkoxycarbonyl group having 15 or more carbon atoms of the hydrophobic benzotriazole derivative is preferably an alkoxycarbonyl group having 15 to 30 carbon atoms, and more preferably an alkoxycarbonyl group having 15 to 20 carbon atoms.

The carbonyl hydrazine group having 15 or more carbon atoms of the hydrophobic benzotriazole derivative is preferably a carbonyl hydrazine group having 15 to 30 carbon atoms and having 15 to 20 carbon atoms. The carbonylamine group is more preferred.

The amine carbonyl group having 1 or more carbon atoms of the hydrophobic benzotriazole derivative is preferably an amine carbonyl group having 1 to 10 carbon atoms, more preferably an amine carbonyl group having 1 to 5 carbon atoms.

Among these substituents, an unsubstituted alkyl group is preferred.

From the viewpoint of good control of depression and erosion, the number of substituents of the hydrophobic benzotriazole derivative is preferably from 1 to 3, more preferably 1, two.

In the hydrophobic benzotriazole derivative, the position substituted by the substituent is not specific, and when the number of the substituent is 3, it is preferably substituted with a substituent at the 1-, 3-, and 4-positions, and the substituent is preferably substituted. When the number of the substituents is 2, it is preferred to substitute the substituents at the 1-position and the 3-position or the 3-position and the 4-position. When the number of the substituents is 1, it is preferred to substitute the substituents at the 1-position or the 3-position.

The (C) hydrophobic benzotriazole derivative is specifically exemplified below, and the present invention is not limited to these.

The amount of the hydrophobic benzotriazole derivative to be added is preferably 0.0001% by mass or more and 3% by mass or less based on the mass of the polishing liquid used for polishing, and is preferably 0.005% by mass or more. 1% by mass or less is more preferable.

(B) The total concentration of the hydrophilic benzotriazole derivative and the (C) hydrophobic benzotriazole derivative is 0.005% by mass or more and 5% by mass or less based on the polishing liquid used for polishing. Preferably, it is 0.01% by mass or more and 3% by mass or less, more preferably 0.03% by mass or more and 1% by mass or less.

From the viewpoint of good control of depression and erosion, (B) the ratio of the content of the hydrophilic benzotriazole derivative to the (C) hydrophobic benzotriazole derivative is by mass ratio 2:1~1:5 is better, 3:2~1:5 is better, 1:1~1:5 is better.

The polishing liquid of the present invention may also be used in combination with (B) a hydrophilic benzotriazole derivative and (C) a hydrophobic benzotriazole derivative, and other azole compounds.

The content of the (B) hydrophilic benzotriazole derivative and (C) hydrophobic benzotriazole derivative may be 50% by mass relative to all of the benzotriazole used in the polishing liquid at the time of polishing. ~100% by mass, preferably 60% by mass to 90% by mass, more preferably 70% by mass to 90% by mass.

The other pyrrole derivatives may be triazoles such as tolutriazole, 1-(1,2-dicarboxyethyl)toluenetriazole, 1-[N,N-bis(hydroxyethyl)aminemethyl]tolutriazole Derivatives, general known corrosion inhibitors such as imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, etc., and derivatives thereof, of which 1,2 3-triazole, 1,2,4-triazole and tetrazole are preferred.

(D) oxidant

The polishing liquid of the present invention contains an oxidizing agent which can oxidize the metal to be polished.

Examples of the oxidizing agent include hydrogen peroxide, peroxide, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, and persulfate. , dichromate, permanganate, ozone water and silver (II) salt, iron (III) salt.

As the iron (III) salt, there are inorganic iron (III) salts such as iron (III) nitrate, iron (III) chloride, iron (III) sulfate, and iron (III) oxide, and the organic error of iron (III). salt.

When an organic salt of iron (III) is used, the complex compound constituting the iron (III) salt is, for example, acetic acid, citric acid, oxalic acid, salicylic acid, diethyldithiocarbamic acid, succinic acid, tartaric acid, glycolic acid. Glycine, alanine, aspartic acid, Sulfuric acid, ethylenediamine, trimethylenediamine, diethylene glycol, triethylene glycol, 1,2-ethanedithiol, malonic acid, glutaric acid, 3-hydroxybutyric acid, propionic acid, citric acid , isodecanoic acid, 3-hydroxyrculphonic acid, 3,5-dihydroxysulphate, gallic acid, benzoic acid, maleic acid, etc., salts thereof, amine polycarboxylic acids and salts thereof.

Amine polycarboxylic acid and its salts are ethylenediamine-N,N,N',N'-tetraacetic acid, diethylenetriaminepentaacetic acid, 1,3-diaminepropane-N,N,N',N' -tetraacetic acid, 1,2-diaminopropane-N,N,N',N'-tetraacetic acid, ethylenediamine-N,N'-disuccinic acid (racemic), ethylenediamine disuccinic acid ( SS body), N-(2-formateethyl)-L-aspartic acid, N-(carboxymethyl)-L-aspartic acid, β-alanine diacetic acid, methylimine diacetic acid, Nitrotriacetic acid, cyclohexanediaminetetraacetic acid, imine diacetic acid, glycol ether diamine tetraacetic acid, ethylenediamine-1-N, N'-diacetic acid, ethylenediamine o-hydroxyphenylacetic acid, N, N- Bis(2-hydroxybenzyl)ethylenediamine-N,N-diacetic acid and the like and salts thereof. The salt type is preferably an alkali metal salt or an ammonium salt, and an ammonium salt is particularly preferred.

Among these oxidizing agents, organic acid salts of hydrogen peroxide, iodate, hypochlorite, chlorate, persulfate and iron (III) are preferred, and it is preferred to use the organic salt of iron (III). The coordination compound may, for example, be citric acid, tartaric acid or an amine polycarboxylic acid (specifically, ethylenediamine-N, N, N', N'-tetraacetic acid, diethylenetriaminepentaacetic acid, 1,3- Diamine propane-N,N,N',N'-tetraacetic acid, ethylenediamine-N,N'-disuccinic acid (racemic), ethylenediamine disuccinic acid (SS body), N-(2 -formate ethyl)-L-aspartic acid, N-(carboxymethyl)-L-aspartic acid, β-alanine diacetic acid, methylimine diacetic acid, nitrogen triacetic acid, imine diacetic acid ).

The oxidant is further hydrogen peroxide, persulfate and iron (III) ethylenediamine-N,N,N',N'-tetraacetic acid, 1,3-diaminepropane-N,N,N',N' A complex of tetraacetic acid and ethylenediamine disuccinic acid (SS body) is preferred.

The oxidizing agent is preferably used in a composition which is mixed with a component other than the oxidizing agent when it is polished using a polishing liquid. The timing of mixing the oxidizing agent is preferably within 1 hour before the use of the polishing liquid, and preferably within 5 minutes; more preferably, the mixer is just before the polishing liquid is supplied to the polishing device, and is just supplied to the surface to be polished. Mix within 5 seconds before.

The amount of the oxidizing agent to be added is preferably 0.001% by mass or more and 5% by mass or less, and more preferably 0.003% by mass or more and 3% by mass or less, per 1 L of the polishing liquid for polishing. In other words, the high CMP rate is ensured by the sufficient oxidation of the metal, and the amount of the oxidizing agent added is preferably 0.001% by mass or more, and more preferably 5% by mass or less based on the roughness of the polishing surface.

(E) organic acid

In the present invention, the polishing liquid may further contain organic acid. This so-called organic acid is used to promote oxidation, adjust pH, and act as a buffer. The compound having an organic acid-based structure different from the oxidizing agent for oxidizing a metal in the present invention does not include the above-mentioned acid having an oxidizing agent function.

The organic acid in the present invention is preferably selected from the group consisting of the following.

That is, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, Orthoheptanoic 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, citric acid, malic acid, tartaric acid, citric acid, lactic acid and salts of such ammonium salts, alkali metal salts, sulfuric acid, nitric acid, ammonia, ammonium salts or mixtures thereof Wait.

Among these, formic acid, malonic acid, malic acid, tartaric acid, and citric acid are suitable. A laminate film comprising at least one metal layer selected from the group consisting of copper, a copper alloy, and an oxide of copper or a copper alloy.

The organic acid in the present invention may, for example, be an amino acid or the like.

The amino acid or the like is preferably water-soluble, and is preferably selected from the group consisting of the following.

That is, it is preferable to contain, for example, glycine, L-alanine, β-alanine, L-2-aminobutyric acid, L-nuronic acid, L-proline, L-leucine, L-positive Aleucine, L-isoleucine, L-isoisoleucine, L-phenylalanine, L-proline, creatinine, L-ornithine, L-lysine, taurine, L-serine, L-chymidine, L-Butylamine, L-homoserine, L-tyramine, 3,5-diiodo-L-tyrosine, β-(3,4 -dihydroxyphenyl)-L-alanine, L-thyroxine, 4-hydroxy-L-proline, L-thiocyanate, L-methionine, L-ethylthioacetate, L-wool Thiamine, L-cystathion, L-cystine, L-cysteine, L-aspartic acid, L-glutamic acid, S-(carboxymethyl)-L-thiocyanate, 4-aminobutyric acid, L-aspartic acid, L-glutamic acid, nitrogen serine, L-arginine, L-cutosin, L-citrulline, δ-hydroxy- L-lysine, creatine, L-canine urea, L-histidine, 1-methyl-L-histidine, 3-methyl-L-histidine, ergot sulfate, L-color Amino acid, actinomycin C1, apamin ( At least one of amino acids such as Apamin), vasopressin I, vasopressin II, and antipain.

Among them, malic acid, tartaric acid, citric acid, glycine acid, and glycolic acid are preferable because they can maintain a practical CMP rate and effectively suppress the etching rate.

The amount of the organic acid to be added is preferably 0.0005 to 0.5 mol, more preferably 0.005 to 0.3 mol, and particularly preferably 0.01 to 0.1 mol, per 1 L of the polishing liquid used for polishing. That is, based on the suppression of erosion, the amount of organic acid added is less than 0.5 mol. Preferably, it is preferably 0.0005 mol or more for sufficient effect.

(F) water soluble polymer

The polishing liquid of the present invention may contain a water-soluble polymer as a preferred component.

(F) Water-soluble polymer may be exemplified by polysaccharides (for example, alginic acid, pectic acid, carboxymethyl cellulose, acacia, sinosaur, polyglucosamine, methyl glycol polyglucosamine, A Cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, polytriglucose Polycarboxylic acid and its derivatives (for example, polyacrylic acid, polymethacrylic acid, polyaspartic acid, polyglutamic acid, polylysine, polymalic acid, polymaleic acid, polyicon) Acid, polyfumaric acid, poly(p-styrenecarboxylic acid), polyvinylsulfuric acid, polyaminoacrylamide, polylysine, polyglyoxylic acid, polyethyleneimine, vinyl polymer (eg polyvinyl alcohol) , polyvinylpyrrolidone, polyacrylaldehyde), polyglycols (such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol), etc.; preferably, there are polysaccharides (such as alginic acid, pectic acid) , carboxymethyl cellulose, Chinese cabbage, Sanxian gum, polyglucosamine, methyl glycol polyglucosamine, methyl cellulose, ethyl cellulose, Methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, carboxyethylcellulose, polytriglucose), polycarboxylic acids and derivatives thereof For example, polyacrylic acid, polymethacrylic acid, polyaspartic acid, polyglutamic acid, polylysine, polymalic acid, polymaleic acid, polyiconic acid, polyfumaric acid, poly(p-styrene) Formic acid), polyvinyl sulphate, polyamino acrylamide, poly phthalic acid, polyglyoxylic acid), polyethyleneimine, vinyl polymer (eg polyvinyl alcohol, poly Vinyl pyrrolidone, polyacrylaldehyde).

Only when the substrate for semiconductor system is used for the polishing system, there is no contamination with alkali metals, alkaline earth metals, halides, etc. Therefore, when the water-soluble polymer is acid, it is preferable to directly use the acid or its ammonium salt. use.

(F) The amount of the water-soluble polymer to be added is preferably 0.001 to 10 g per 1 L of the total amount of the polishing liquid used for the polishing, and more preferably 0.01 to 5 g, more preferably 0.1 to 3 g. In other words, in order to obtain a sufficient effect, the amount of the water-soluble polymer added is preferably 0.001 g or more, and more preferably 10 g or less based on the prevention of a decrease in the CMP rate.

(F) The weight average molecular weight of the water-soluble polymer is preferably from 500 to 100,000, more preferably from 2,000 to 50,000.

The (F) water-soluble polymer according to the present invention may be used alone or in combination of two or more.

(F) The mass ratio of the water-soluble polymer to the (A) colloidal vermiculite particles is preferably 0.0001:1 to 1:0.001, more preferably 0.001:1 to 1:0.01, and particularly preferably 0.005:1 to 1:0.1. .

[Other ingredients]

In addition to the essential component (A) component to the component (D) and the component (E) and the component (F), the polishing liquid of the present invention may be used in combination with other effects without departing from the effects of the present invention. ingredient.

(G) quaternary ammonium cation

The polishing liquid of the present invention may contain a quaternary ammonium cation (hereinafter referred to as "specific cation" or "quaternary ammonium cation") having one or more quaternary nitrogen atoms in the molecule (G) as a preferred component.

Although the role of the quaternary ammonium cation is not clear, it is presumed as follows.

That is, the quaternary ammonium cation in the polishing liquid is adsorbed on the surface of the abrasive particles, and the interaction between the abrasive particles and the surface to be polished is enhanced. More specifically, the repulsive force between the negatively charged abrasive particles on the surface and the negatively charged surface of the surface is moderated by the quaternary ammonium cation. As a result, the abrasive particles are enhanced by the physical action (physical scraping action) between the polished faces, and the polishing speed for each film type is increased.

In the present invention, the quaternary ammonium cation is not particularly limited as long as it has a structure containing 1 or more quaternary nitrogen in the molecular structure. Among them, from the viewpoint of sufficiently increasing the polishing rate, it is preferred to use a cation of the following general formula (1) or general formula (2).

In the general formula (1) and the general formula (2), R ¹ to R ⁶ each independently represent an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group or an aralkyl group having 1 to 20 carbon atoms, and may also be R ^{1 .} Among the ~R ⁶ , 2 are combined with each other to form a ring structure.

Specific examples of the alkyl group having 1 to 20 carbon atoms of R ¹ to R ⁶ include a methyl group, a noyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group and the like. Ethyl, propyl and butyl are preferred.

The alkenyl group of R ¹ to R ⁶ is preferably a carbon number of 2 to 10, and specific examples thereof include a vinyl group and a propenyl group.

Specific examples of the cycloalkyl group of R ¹ to R ⁶ include a cyclohexyl group and a cyclopentyl group, and among them, a cyclohexyl group is preferred.

Specific examples of the aryl group of R ¹ to R ⁶ include a phenyl group and a naphthyl group, and among them, a phenyl group is preferred.

Specific examples of the aralkyl group as the R ¹ to R ⁶ include a benzyl group, and a benzyl group is preferred.

Each of R ¹ to R ⁶ may have a substituent, and examples of the substituent which may be introduced include a hydroxyl group, an amine group, a carboxyl group, a heterocyclic group, a pyridyl group, an amine alkyl group, a phosphoric acid group, and an imido group. A thiol group, a sulfonic acid group, a nitro group or the like.

In the general formula (2), an alkyl group having an alkyl group having 1 to 10 carbon atoms in the X group, an alkenyl group, a cycloalkyl group, an aryl group or a group of 2 or more is combined.

Further, in addition to the organic linking group, the linking group represented by X may contain -S-, -S(=O) ₂ -, -O-, -C(=O)- in the chain.

The alkylene group having 1 to 10 carbon atoms specifically has a methylene group, an alkenyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, a octyl group, etc. It is better to stretch the base.

Specific examples of the alkenyl group include a vinyl group, a propenyl group, and the like. The propylene base is preferred.

Specific examples of the cycloalkyl group include a cyclohexylene group, a cycloheptyl group, and the like. Among them, a cyclohexylene group is preferred.

Specific examples of the aryl group include a stretched phenyl group and a stretched naphthyl group, of which a phenyl group is preferred.

Each of the linking groups may have a more substituent, and examples of the substituent which may be introduced include a hydroxyl group, an amine group, a sulfonyl group, a carboxyl group, a heterocyclic group, a pyridyl group, an amine alkyl group, a phosphoric acid group, an imido group, and sulfur. Alcohol group, sulfonic acid group, nitro group and the like.

The quaternary ammonium cation (specific cation) [exemplified compounds (A1) to (A46)] in the present invention is specifically exemplified below, but the present invention is not limited thereto.

From the viewpoint of dispersion stability in the slurry, as in the above (G) level four Among the ammonium cations (specific cations), A8, A10, A11, A12, A36, A37, and A46 are preferred.

The (G) quaternary ammonium cation (specific cation) in the present invention can be synthesized, for example, by using a hydroxy substitution reaction using ammonia, various amines or the like as a nucleating agent.

General commercially available reagents can also be purchased.

In the present invention, the (G) quaternary ammonium cation (specific cation) is added in an amount relative to the polishing liquid used for polishing (that is, the diluted slurry after dilution with water or an aqueous solution. The polishing liquid at the time of polishing is preferably 0.0001% by mass or more and 1% by mass or less, more preferably 0.001% by mass or more and 0.3% by mass or less. In other words, the amount of the cation added is preferably 0.0001% by mass or more from the viewpoint of sufficiently increasing the polishing rate, and is preferably 1% by mass or less from the viewpoint of sufficient slurry stability.

The (G) quaternary ammonium cation (specific cation) according to the present invention may be used alone or in combination of two or more.

(H) surfactant

The slurry of the present invention may be used in combination with a surfactant. The surfactant which can be used together may be an anionic surfactant or a cationic surfactant.

Specific examples of the anionic surfactant include compounds such as toluenesulfonic acid, dodecylsulfonic acid, tetradecylsulfonic acid, hexadecanesulfonic acid, dodecanesulfonic acid, and tetradecanesulfonic acid.

The cationic surfactants are specifically, for example, lauryl trimethylammonium, lauryl triethylammonium, stearyl trimethylammonium, palmityl trimethylammonium, octyltrimethylammonium, dodecylpyridinium, decylpyridinium, octylpyridinium, etc. Compound.

Anionic surfactants useful in the present invention, in addition to the sulfonate The preferred ones are carboxylate, sulfate, and phosphate salts.

More specifically, suitable carboxylates are soaps, N-mercaptoamines, polyoxyethylene or polyoxypropylene alkyl ether carboxylates, deuterated peptides; sulfates are sulfated oils, alkyl sulfates Salt, alkyl ether sulfate, polyoxyethylene or polyoxypropylene alkyl ether sulfate, alkyl decylamine sulfate; phosphate salt is alkyl phosphate, polyoxyethylene or polyoxypropylene alkyl ether phosphate.

The amount of the surfactant to be added is preferably 0.001 to 10 g per 1 L of the total amount of the polishing liquid used for the polishing, and more preferably 0.01 to 5 g, more preferably 0.01 to 1 g. In other words, the amount of the surfactant to be added is preferably 0.01 g or more in order to obtain a sufficient effect, and preferably 1 g or less in order to prevent the CMP from being lowered.

The surfactant may be used singly or in combination of two or more.

(I) pH adjuster

The polishing liquid of the present invention is preferably pH 2 to 5, more preferably pH 2 to 4, and particularly preferably pH 2.5 to 4. The polishing rate of the interlayer insulating film can be more effectively adjusted by controlling the pH of the polishing liquid as above.

The polishing liquid for metal of the present invention preferably has a specific pH, and is preferably added with a base/acid or a buffer.

The alkali/acid or buffering agent is preferably an organic ammonium hydroxide such as ammonium hydroxide or tetramethylammonium hydroxide, or a non-metal alkaline agent such as an alkanolamine such as diethanolamine, triethanolamine or triisopropanolamine. An alkali metal hydroxide such as sodium hydroxide, potassium hydroxide or lithium hydroxide; an inorganic acid such as nitric acid, sulfuric acid or phosphoric acid; a carbonate such as sodium carbonate; a phosphate such as trisodium phosphate; a borate or a tetraborate; Hydroxybenzoate and the like. Optimum alkali agent is ammonium hydroxide, potassium hydroxide, hydrogen Lithium oxide and tetramethylammonium hydroxide.

The alkali or the buffering agent is preferably a non-metal alkaline agent such as an organic ammonium hydroxide such as ammonia, ammonium hydroxide or tetramethylammonium hydroxide, or an alkanolamine such as diethanolamine, triethanolamine or triisopropanolamine. An alkali metal hydroxide such as sodium hydroxide, potassium hydroxide or lithium hydroxide.

Particularly preferred bases are ammonium hydroxide, potassium hydroxide, lithium hydroxide and tetramethylammonium hydroxide.

The amount of the base or the buffer to be added may be maintained in a good range, and it is preferably 0.0001 mol to 1.0 mol, more preferably 0.003 mol to 0.5 mol, per 1 L of the polishing liquid used for polishing.

(J) Chelating agent

The polishing liquid of the present invention preferably has a chelating agent (i.e., a hard water softening agent) as needed to reduce the adverse effects of the polyvalent metal ions or the like which are mixed therein.

The chelating agent is a hard water softening agent (precipitation preventing agent for calcium and magnesium), and related compounds, and examples thereof include nitrogen triacetic acid, diethylene triamine pentaacetic acid, ethylenediaminetetraacetic acid, and N, N, N-. Trimethanesulfonic acid, ethylenediamine-N,N,N',N'-tetramethylenesulfonic acid, transcyclohexanediaminetetraacetic acid, 1,2-diaminepropanetetraacetic acid, glycol ether diamine IV Acetic acid, ethylenediamine o-hydroxyphenylacetic acid, ethylenediamine disuccinic acid (SS body), N-(2-formateethyl)-L-aspartic acid, β-alanine diacetic acid, 2-phosphonium Alkane-1,2,4-tricarboxylic acid, 1-hydroxyethylidene-1,1-disulfonic acid, N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid 1,2-dihydroxybenzene-4,6-disulfonic acid and the like.

The chelating agent may be used in combination of two or more kinds as necessary.

If the amount of the chelating agent is added, the polyvalent metal ions mixed in, etc. can be sufficiently blocked. The metal ion is preferably added to, for example, 0.003 mol to 0.07 mol of the polishing liquid used in the polishing.

[Use of polishing liquid]

In general, the polishing liquid of the present invention is suitable for polishing a barrier layer which prevents the diffusion of copper existing between a wiring composed of a copper metal and/or a copper alloy and an interlayer insulating film.

In the barrier layer CMP, the polishing liquid of the present invention is also applicable when the barrier layer polishing and the insulating layer polishing are performed in one stage, and therefore the polishing liquid of the present invention is also suitable for the polishing of the insulating layer.

[Barrier Metal Material]

The material constituting the barrier layer is generally a low-resistance metal material, and TiN, TiW, Ta, TaN, W, WN, Ru, etc. are suitable, and Ta and TaN are preferred. The polishing liquid of the present invention is also applicable to a barrier layer formed of Mn, Ti, Ru or the like other than the Ta-based metal material.

[Interlayer insulating film]

The interlayer insulating film (insulating layer) may be, for example, a material having a low permittivity (for example, an organic polymer system, a SiOC system, or a SiOF system) having a relative permittivity of about 3.5 to 2.0, in addition to a conventional interlayer insulating film such as TEOS. An interlayer insulating film of a Low-k film).

Specifically, materials for forming a low permittivity interlayer insulating film include SiOC-based HSG-R7 (Hitachi Chemical Industries, Ltd.), BLACKDIAMOND (Applied Materials, Inc.), and the like.

Such a Low-k film is usually under the TEOS insulating film, and a barrier layer and a metal wiring are formed on the TEOS insulating film.

[Metal wiring raw materials]

In the present invention, the object to be polished (the object to be polished) is preferably a wiring made of copper metal and/or a copper alloy, for example, which is suitable for a semiconductor integrated circuit such as LSI. The raw material of this wiring is preferably copper alloy. Among the copper alloys, copper alloy containing silver is more preferable.

The silver content of the copper alloy is preferably 40% by mass or less, more preferably 10% by mass or less, and particularly preferably 1% by mass or less, and the copper alloy in an amount of 0.00001 to 0.1% by mass can exert an optimum effect.

[Wiring thickness]

In the present invention, when the object to be polished (the object to be polished) is used for, for example, a DRAM element system, it is preferable to have a wiring having a half pitch of 0.15 μm or less, more preferably 0.10 μm or less, and even more preferably 0.08 μm or less.

On the other hand, when the polishing system is used in, for example, an MPU element system, it is preferable to have a wiring of 012 μm or less, preferably 009 μm or less, and preferably 0.07 μm or less.

The polishing liquid of the present invention described above particularly exhibits an excellent effect on the object to be polished having such wiring.

[grinding method]

In the polishing liquid of the present invention, (1) is a concentrated liquid, and when it is used, water or an aqueous solution is diluted into a use liquid, and (2) each component is prepared in the form of an aqueous solution described below, and these are mixed, and if necessary, water is diluted to a use liquid. (3) Modulation is used as a liquid.

The polishing method using the polishing liquid of the present invention may employ any one of the polishing liquids.

This polishing method is a method of supplying a polishing liquid to a polishing pad on a polishing table to bring it into contact with a surface to be polished of the object to be polished, and to move the surface to be polished relative to the polishing pad.

The apparatus for polishing may be a general polishing apparatus including a holder for holding a workpiece to be polished (for example, a wafer on which a film of a conductive material is formed), and a polishing pad attached thereto A grinding platform such as a variable number of motors. As the polishing pad, a general non-woven fabric, a foamed polyurethane, a porous fluororesin or the like can be used without particular limitation.

The polishing conditions are not particularly limited, and the rotation speed of the polishing table is preferably a low number of revolutions of 200 rpm or less which does not cause the object to be polished to fly out. The pressure of the object to be polished having the surface to be polished (the film to be polished) is preferably 0.68 to 34.5 KPa, and the in-plane uniformity of the object to be polished and the flatness of the pattern at the polishing rate are 3.40. ~20.7KPa is better.

During the polishing, the polishing liquid is continuously supplied to the polishing pad by a pump or the like.

After the completion of the polishing, the object to be polished is sufficiently washed in running water, and then the water droplets adhering to the object to be polished are removed by a spin dryer or the like to be dried.

In the present invention, as the method (1), when the concentrate is diluted, the aqueous solution shown below can be used. The aqueous solution contains at least one of (A) colloidal vermiculite particles, (B) a hydrophilic benzotriazole derivative, (C) a hydrophobic benzotriazole derivative, and (D) an oxidizing agent. The components contained in the aqueous solution and the components contained in the concentrated liquid to be diluted are used as components of the polishing liquid (use liquid) used for polishing.

Thus, when the concentrate is diluted with an aqueous solution, the component which is difficult to dissolve can be prepared in the form of an aqueous solution, and a more concentrated concentrate can be prepared.

Further, the method of diluting the concentrated liquid with water or an aqueous solution may be a method in which a pipe for supplying the concentrated polishing liquid and a pipe for supplying water or an aqueous solution are mixed and mixed in the middle, and a mixture of the diluted and used polishing liquid is supplied to the polishing pad. . The mixing of the concentrated liquid with water or an aqueous solution may be carried out by a method in which a liquid is mutually impact-mixed by a narrow passage in a pressurized state, a method of providing a power rotating blade in a pipe, and the like.

The supply rate of the polishing liquid is preferably 10 to 1000 ml/min, and is preferably 170 to 800 ml/min in order to satisfy the uniformity in the surface to be polished and the flatness of the pattern at the polishing rate.

Further, the concentrated liquid is diluted with water or an aqueous solution, and is separately supplied with a pipe for supplying the polishing liquid and a pipe for supplying water or an aqueous solution, each of which supplies a specific amount of liquid to the polishing pad, and the polishing pad is opposed to the surface to be polished. A method of mixing and grinding one side. Further, a method in which a specific amount of the concentrated liquid is mixed with water or an aqueous solution in a container, and the mixed polishing liquid is supplied to the polishing pad to be ground may be used.

Other grinding methods include dividing the components contained in the polishing liquid into at least two constituent components, and when they are used, they are diluted with water or an aqueous solution, and are supplied to the polishing pad on the polishing table to be in contact with the surface to be polished, so that the surface to be polished and the polishing pad are used. The method of grinding relative to motion.

For example, the oxidizing agent may be the component (A), the other additives and water may be the component (B), and when used, the component (A) and the component (B) may be diluted with water or an aqueous solution.

The additive having low solubility can also be divided into constituent components (A) and (B), and the component (A) and the constituent component (B) are diluted in the water or aqueous solution at the time of use. And use.

In the above example, it is necessary to have three pipes for supplying the component (A), the component (B), and the water or the aqueous solution, and the dilution mixing system is to combine the three pipes into one pipe to be supplied to the polishing pad, and to mix in the pipe. In this case, it is also possible to combine 2 pipes and combine the other pipes. Specifically, it is a method in which a component containing a non-dissolvable additive and other constituent components are mixed, and a mixing path is extended to secure a dissolution time, and a pipe of water or an aqueous solution is further combined.

Other mixing methods include directly guiding the 3 pipes to the polishing pad, mixing the polishing pad with the relative movement of the surface to be polished, or mixing the components in a container, and then supplying the diluted slurry to the polishing pad. method.

In the above method, the first constituent component containing the oxidizing agent may be kept at 40 ° C or lower, and the other constituent components may be heated at a temperature ranging from room temperature to 100 ° C, and the first constituent component and the other constituent components may be mixed, or diluted with water or an aqueous solution. Then, the liquid temperature is 40 ° C or less. This method is a preferred method for increasing the solubility of a low solubility raw material in the slurry by utilizing a phenomenon in which the temperature is high and the solubility is high.

The raw material which is dissolved by heating the other constituent components in the range of room temperature to 100 ° C is precipitated from the solution when the temperature is lowered. Therefore, when other components in a low temperature state are used, it is necessary to first heat the precipitated raw material to dissolve the precipitated raw material. Here, a means for heating and infusion as a raw material to dissolve other constituent components, a method of first stirring a liquid containing the precipitate, infusion, and heating the tube to dissolve may be employed. When the temperature of the first constituent component containing the oxidizing agent is higher than 40 ° C or higher, the oxidizing agent is decomposed. Therefore, when the other constituent component heated and the first constituent component containing the oxidizing agent are mixed, Compared The best is to make it below 40 °C.

As described above, in the present invention, the components of the polishing liquid may be divided into two or more portions and supplied to the surface to be polished. In this case, it is preferable to supply it as a component containing an oxidizing agent and a component containing an organic acid. The polishing liquid may be a concentrated liquid, and the dilution water may be supplied to the surface to be polished.

In the present invention, when the component of the polishing liquid is divided into two or more parts and supplied to the surface to be polished, the supply amount represents the total amount of supply from each pipe.

〔pad〕

The polishing pad suitable for the polishing method of the present invention may be a non-foamed construction mat or a foamed construction mat. The former pad uses a hard synthetic resin block such as a plastic plate. The latter has three types of independent foam (dry foaming), continuous foam (wet foaming), and two-layer composite (layered), and a two-layer composite (layered) is particularly preferable. Foaming can be uniform or non-uniform.

Further, it is also possible to contain cerium particles (for example, cerium oxide, vermiculite, alumina, resin, etc.) which are generally used for grinding. In terms of hardness, it may be either soft or hard, and it is preferable to use the hardness of each layer in the laminated layer. The material is preferably non-woven fabric, artificial leather, polyamide, polyurethane, polyester, polycarbonate, and the like. It is also possible to apply lattice grooves/cavities/concentric grooves/spiral grooves to the surface in contact with the surface to be polished.

[wafer]

In the present invention, the target of CMP by the polishing liquid is preferably a wafer having a diameter of 200 mm or more, and preferably 300 mm or more. The effect of the present invention is remarkable in the case of 300 mm or more.

[grinding device]

The apparatus which can perform grinding using the polishing liquid of the present invention is not particularly limited, and there are Mirra Mesa CMP, Reflexion CMP (Applied Materials), FREX200, FREX300 (荏原制所), NPS3301, NPS2301 (Nikon), A-FP-310A, A- FP-210A (Tokyo Precision), 2300 TERES (Lam Research), Momentum (Speedfam IPEC), etc.

Example

The invention will be described in more detail below by way of examples, but the invention is not limited thereto.

[Example 1]

A polishing liquid having the composition shown below was prepared, and a polishing experiment was performed.

<Composition (1)>

<Evaluation method> In the polishing apparatus, the apparatus MA-300D manufactured by MUSASINO Electronics Co., Ltd. was used, and the following wafer was polished while supplying the slurry under the following conditions.

<grinding object> The wafers for dent and erosion evaluation are prepared as follows.

First, the ruthenium oxide film on the Si substrate is patterned by a photolithography step and a reactive ion etching step to form a wiring trench and a connection hole having a width of 0.09 to 100 μm and a depth of 600 nm. Next, a Ta film having a thickness of 20 nm was formed by sputtering, followed by sputtering to form a copper film having a thickness of 50 nm. Then, a copper film having a total thickness of 1000 nm was formed by plating. This wafer (commonly referred to as an 854PTN wafer) was cut into 6 × 6 cm to be a wafer to be polished.

<Indentation and erosion assessment> First, the polishing target wafer was polished using a Cu-CMP slurry at a time equivalent to OP + 30%. Then, the wafer was polished using the polishing liquid of the composition (1) for 45 seconds, and the processed wafer was measured for the drop of the line/space portion of 9 μm/1 μm using a stylus type drop meter Dektak V320Si (manufactured by Veeco). For the amount of erosion. The results obtained are shown in Table 1.

[Examples 2 to 7 and Comparative Examples 1 to 4]

The composition in Example 1 was changed, and the composition was adjusted according to the composition described in Table 1 below, and the polishing test was carried out in the same manner as in the polishing conditions of Example 1. The results are shown in Table 1.

The (B) hydrophilic benzotriazole derivatives B1, 2, 4, 5, 7 and (C) hydrophobic benzotriazole derivatives C1 to C4 listed in Table 1 refer to the aforementioned exemplified compounds. The benzotriazole BB1 and BB2 are used as the following compounds.

The compounds referred to in Table 1 are detailed below.

TBAN: tetrabutylammonium nitrate [cationic quaternary ammonium salt compound] TMAN: tetramethylammonium nitrate [cationic quaternary ammonium salt compound] DBSA: dodecylsulfonic acid [surfactant] BTA: 1,2,3- Benzotriazole [corrosion inhibitor]

"-" in Table 1 means that the compound is not added to the item.

The abrasive particles listed in Table 1 are detailed in Table 2 below. In addition, the average particle diameter of the abrasive particles is a measured value of the minimum constituent particle diameter of one particle when the polishing particles are observed by SEM (scanning electron microscope).

The colloidal vermiculite of A-1 to A-3 in Table 2 is a colloidal vermiculite manufactured by Fuso Chemical Co., Ltd. Further, the alumina of A-4 is manufactured by Japan AEROSIL Co., Ltd., and the smog meteorite of A-5 is manufactured by Japan AEROSIL Co., Ltd.

According to Table 1, in comparison with Comparative Examples 1 to 4, when the polishing liquids of Examples 1 to 7 were used, the effect of suppressing depression and erosion was high.

On the other hand, the polishing liquids of Comparative Examples 1 to 4 were inferior to the polishing liquid of the examples in terms of the suppression effect of any of the depression and the etching.

Based on the above, it is understood that the polishing liquid of the present invention can suppress the occurrence of dents and erosion and achieve good flatness.

Claims (15)

A polishing liquid for a chemical mechanical polishing in a planarization step of a semiconductor integrated circuit having a barrier layer, characterized by containing (A) colloidal vermiculite particles, and (B) hydrophilic benzotriene An azole derivative, (C) a hydrophobic benzotriazole derivative, (D) an oxidizing agent, and (F) a water-soluble polymer. The polishing liquid according to claim 1, wherein the (B) hydrophilic benzotriazole derivative has a hydroxyl group, an amine group, a carboxyl group or a sulfonic acid group. The polishing liquid according to claim 1 or 2, wherein the (C) hydrophobic benzotriazole derivative has an unsubstituted alkyl group, an alkoxy group having 10 or more carbon atoms, and a carbon atom number of 15 or more. An alkoxycarbonyl group, a carbonyl hydrazine group having 15 or more carbon atoms or an amine carbonyl group having 15 or more carbon atoms. A slurry according to claim 1 or 2, which further contains an amino acid. The polishing liquid according to claim 1 or 2, wherein the total concentration of the (B) hydrophilic benzotriazole derivative and the (C) hydrophobic benzotriazole derivative is 0.005% by mass or more 5 mass% or less. The polishing liquid according to claim 1 or 2, wherein the content ratio of the (B) hydrophilic benzotriazole derivative to the (C) hydrophobic benzotriazole derivative is 2:1 by mass ratio ~1:5. For example, the polishing liquid of claim 1 or 2, wherein the pH system is 2 to 5. The polishing liquid according to claim 1, wherein the content ratio of the (B) hydrophilic benzotriazole derivative to the (C) hydrophobic benzotriazole derivative is 1:1 to 1 : 5. The polishing liquid according to claim 1, wherein the (F) water-soluble polymer is polyvinyl alcohol or carboxymethyl cellulose, and (F) water-soluble polymer and (A) colloidal vermiculite particles are contained. The ratio is 0.005:1~1:0.1. The polishing liquid of claim 1, which further comprises a quaternary ammonium cation having 1 or more quaternary nitrogen atoms in the (G) molecule. The slurry of claim 1 is further comprising an anionic surfactant. The polishing liquid according to claim 1, wherein the (B) hydrophilic benzotriazole derivative is selected from the group consisting of compounds of B1 to B7. . The polishing liquid according to claim 12, wherein the (B) hydrophilic benzotriazole derivative is B2 or B5. A polishing method characterized by using a polishing liquid according to any one of claims 1 to 13 for chemical mechanical polishing of a semiconductor integrated circuit having a barrier layer. A grinding method according to claim 14, wherein the barrier layer formed of Mn, Ti, Ru or the like is ground.