JP5452859B2 - Metal polishing composition and metal polishing method - Google Patents

Description

The present invention relates to a metal polishing composition and a metal polishing method used in a semiconductor device manufacturing process , and more specifically, a barrier metal layer mainly used for chemical mechanical planarization in a semiconductor device manufacturing process. The present invention relates to a polishing composition used for polishing and a metal polishing method .

In the development of semiconductor devices typified by semiconductor integrated circuits (hereinafter sometimes referred to as “LSI”), in order to increase the integration and speed of semiconductor devices, wiring miniaturization and lamination methods are studied. Has been.
The purpose of miniaturization and lamination of wiring is to prevent diffusion of wiring material into the interlayer insulating film and improve the adhesion of wiring material when forming a metal wiring such as Cu in each layer. As described above, a barrier layer is formed in advance using a barrier metal such as Ta, TaN, Ti, or TiN.

Various techniques such as chemical mechanical polishing (hereinafter sometimes referred to as “CMP”) are employed as techniques for miniaturization and lamination of wiring. CMP polishes an interlayer insulating film (such as SiO ₂ ), a metal thin film used for plug formation or embedded metal wiring, and smoothes the substrate, removes an excessive metal thin film during wiring formation, or removes an excess on the insulating film. It is used for removing a barrier layer.

  Since the barrier metal constituting the barrier layer itself has a conductive property, the barrier layer on the insulating layer must be completely removed in order to prevent an error such as a leakage current.

A general method of CMP is as follows.
A polishing pad is affixed on a circular polishing platen (platen), and the surface of the polishing pad is immersed in a polishing liquid. The surface of the substrate (wafer) is pressed against the polishing pad, and both the polishing platen and the substrate are rotated with a predetermined pressure (polishing pressure) applied from the back surface.
In CMP, the surface of a substrate is flattened by mechanical friction generated by the above operation.

  In order to form each wiring layer, first, a one-stage or multi-stage CMP of a metal film (hereinafter sometimes referred to as “metal film CMP”) for removing excess wiring material deposited by plating or the like is performed. Next, CMP is generally performed to remove the barrier metal material (barrier metal) exposed on the surface by this (hereinafter also referred to as “barrier metal CMP”). However, due to these CMPs, only the center is polished deeper and a dish-like depression (dishing) causes over-polishing of the wiring part, and the surface of a plurality of wiring metal surfaces has dish-shaped recesses. The problem is that it causes a phenomenon (erosion) to form.

  To reduce this dishing, the barrier metal CMP performed after the metal film CMP adjusts the polishing speed of the metal wiring portion and the polishing speed of the barrier metal portion, and finally the wiring having few steps such as dishing and erosion. There is a need to form a layer. That is, in the barrier metal CMP, when the polishing rate of the barrier metal and the interlayer insulating film is relatively low compared to the metal wiring material, the wiring portion is polished faster, and dishing and as a result, erosion occurs. For this reason, it is desirable that the polishing rate of the barrier metal or the insulating film layer is appropriately high. This has the advantage of increasing the throughput of barrier metal CMP, and in fact, dishing is often caused by metal film CMP, and relative polishing rates of barrier metal and insulating film layers are relatively high for the reasons described above. This is also desirable in that it is required to be higher.

  In recent years, wafers have been increased in size to improve productivity. Wafers with a diameter of 200 mm or more have been widely used, and manufacturing with wafers of 300 mm or more has also started. As the size of the wafer increases, the difference in polishing rate between the central portion and the peripheral portion of the wafer tends to increase, and there is a strong demand for uniform polishing within the wafer surface.

  In addition, in the bulk polishing of copper, dishing is likely to occur particularly in a wide metal wiring portion. Therefore, it is desirable that the amount of polishing and removal can be adjusted between the wiring portion and the barrier portion in order to be finally flattened. Therefore, it is desired that the polishing composition for barrier metal CMP has an optimal polishing selectivity for copper / barrier metal. Further, since the wiring pitch and the wiring density are different in each level of the wiring layer, it is further desirable that the polishing selectivity can be adjusted as appropriate.

  The metal polishing composition used for CMP generally contains abrasive grains (for example, alumina and silica) and an oxidizing agent (for example, hydrogen peroxide and persulfuric acid). It is considered that the basic mechanism is polishing by oxidizing the metal surface with an oxidizing agent and removing the oxide film with abrasive grains.

However, when CMP is performed using a polishing liquid containing such solid abrasive grains, scratches (scratches), a phenomenon in which the entire polishing surface is polished more than necessary (thinning), or dishing or erosion described above may occur. May occur.
Moreover, the use of a polishing liquid containing solid abrasive grains complicates the cleaning process normally performed to remove the polishing liquid remaining on the semiconductor surface after polishing, and further, the cleaning liquid (waste liquid) is removed. In order to process, there exists a problem in terms of cost, for example, it is necessary to settle and separate solid abrasive grains.

The following various studies have been made on the polishing liquid containing such solid abrasive grains.
For example, by controlling electrical conductivity using cerium oxide particles, a CMP abrasive and a polishing method (for example, refer to Patent Document 1) aimed at high-speed polishing with almost no polishing scratches generated, colloidal. Polishing composition and polishing method (for example, refer to Patent Document 2) having improved cleaning performance in CMP using silica and bicarbonate, and prevention of aggregation of abrasive grains by controlling pH and electric conductivity A polishing composition (see, for example, Patent Document 3) used for an optical fiber ferrule designed to achieve the above has been proposed. However, even with the polishing liquid as described above, a technique that can achieve a high polishing rate when polishing the barrier layer and suppress scratches caused by aggregation of solid abrasive grains has not yet been obtained. There is no current situation.
JP 2003-17446 A JP 2003-142435 A JP 2000-84832 A

An object of the present invention is a polishing liquid using a solid abrasive grain used for barrier CMP for polishing a barrier layer mainly composed of a barrier metal material , and a metal polishing method, and an excellent polishing rate for a barrier layer is obtained. And it is providing the polishing liquid which can achieve suppression of a scratch , and a metal grinding | polishing method .

  As a result of intensive studies, the present inventor has found that the above-described problems can be solved by the following metal polishing composition, and has completed the present invention. That is, the means for solving the problems of the present invention are as follows.

<1> A diphosphonium salt represented by the following general formula (1) , (B) a corrosion inhibitor, and (C) colloidal silica, which are used for chemical mechanical polishing in a semiconductor device manufacturing process. A metal polishing composition characterized by the above.

[In General Formula (1), R ^{1 to} R ⁶ each independently represents an aliphatic hydrocarbon group or an aryl group, and two of R ^{1 to} R ⁶ may be bonded to each other. L represents a divalent linking group, X represents a group that can be a monovalent or divalent anion, and n represents 1 or 2. ]
<2> The metal polishing composition according to <1>, wherein the pH when used for polishing the metal polishing composition is in the range of 2.5 to 5.0.

<3> The metal polishing composition according to <1> or <2>, further containing an oxidizing agent .

< 4 > The (B) corrosion inhibitor is 1,2,3-benzotriazole, 5,6-dimethyl-1,2,3-benzotriazole, 1- (1,2-dicarboxyethyl) benzotriazole, Any one of <1> to < 3 >, which is at least one compound selected from the group consisting of 1- [N, N-bis (hydroxyethyl) aminomethyl] benzotriazole and 1- (hydroxymethyl) benzotriazole 2. The metal polishing composition according to item 1.
< 5 > The metal polishing according to any one of <1> to < 4 >, wherein the concentration of the (C) colloidal silica is 0.5 to 15% by mass with respect to the total mass of the metal polishing composition. Composition.

More preferable embodiments include the following.
< 6 > Furthermore, (D) The compound for metal polishing characterized by including the compound which has a carboxyl group.
< 7 > The metal polishing composition, wherein the compound having a carboxyl group is a compound represented by the following general formula (2).

In general formula (2), R ⁷ and R ⁸ each independently represent a hydrocarbon group. R ⁷ and R ⁸ may be bonded to each other to form a cyclic structure.

< 8 > A metal polishing composition comprising an anionic surfactant or a cationic surfactant.
< 9 > The metal polishing composition wherein the primary average particle diameter of the (C) colloidal silica is in the range of 20 to 50 nm.
< 10 > Supplying the above metal polishing composition to a polishing pad on a polishing surface plate, bringing the polishing pad into contact with the surface to be polished of the object to be polished, and causing the surface to be polished and the polishing pad to move relative to each other. Metal polishing method by the method.

  Although the operation of the present invention is not clear, it is presumed as follows. That is, it is considered that the interaction between the abrasive particles and the surface to be polished is strengthened by the adsorption of the cation portion of the phosphonium salt in the polishing composition onto the surface of the abrasive particles (colloidal silica). More specifically, it is considered that the phosphonium cation relaxes the repulsive force between the abrasive particles whose surface is negatively charged and the surface to be polished whose surface is negatively charged. As a result, it is considered that the physical action (physical scratch removal action) between the abrasive particles and the surface to be polished becomes stronger, and the polishing rate for each film type is improved. In addition, the scratch is considered to be one of the factors that the physical action is locally increased by agglomeration of abrasive particles and generation of coarse polishing scraps, but in the addition of the phosphonium salt of the present invention, It is thought that scratches were reduced because it was difficult for such phenomena to occur.

According to the present invention, the polishing rate excellent for the barrier layer of a barrier metal material is obtained, and it is possible to provide a metal polishing composition capable of achieving scratch suppression, and a metal polishing method.

Hereinafter, the metal polishing composition of the present invention will be described in detail.
The metal polishing composition of the present invention comprises the diphosphonium salt represented by the general formula (1), (B) a corrosion inhibitor, and (C) colloidal silica, and has a pH of 2.5. it is preferably in the range of 5.0, if necessary, but it may also contain optional ingredients.

In the present invention, the “metal polishing composition” includes not only a polishing liquid used for polishing (that is, a polishing liquid diluted as necessary) but also a concentrated liquid of the polishing liquid. The concentrated liquid or the concentrated polishing liquid means a polishing liquid prepared with a higher solute concentration than the polishing liquid used for polishing, and is diluted with water or an aqueous solution when used for polishing. And used for polishing. The dilution factor is generally 1 to 20 volume times. In this specification, “concentration” and “concentrated liquid” are used in accordance with conventional expressions meaning “thick” and “thick liquid” rather than the state of use, and generally involve physical concentration operations such as evaporation. The term is used in a different way from the meaning of common terms.
Hereinafter, each component which comprises the metal polishing composition of this invention is demonstrated in detail.
In addition, each component which the metal polishing composition of this invention contains may be used individually by 1 type, respectively, and may use 2 or more types together.

[(A) Phosphonium salt]
The polishing liquid of the present invention contains a phosphonium salt. The phosphonium salt in the present invention is not particularly limited as long as it has a quaternary phosphorus atom in the molecular structure. Among these, a diphosphonium salt represented by the following general formula (1) is preferable from the viewpoint of achieving a sufficient improvement in polishing rate.

In general formula (1), R ^{1 to} R ⁶ each independently represents an aliphatic hydrocarbon group that may have a substituent or an aryl group that may have a substituent, and R ¹ to R ⁶ Two of R ⁶ may be bonded to each other. L represents a divalent linking group, X represents a group that can be a monovalent or divalent anion, and n represents 1 or 2.

In the general formula (1), as the aliphatic hydrocarbon group represented by R ^{1 to} R ⁶ , the total number of carbons (here, “total number of carbons” refers to the number of carbons including the carbon number of the substituent). Hereinafter, “total carbon number” is used in the same meaning) 1-30 alkyl group, alkenyl group having 2-30 total carbons (in the present invention, alkenyl groups include cycloalkenyl groups, bicycloalkenyl groups, etc.) An unsaturated aliphatic group having a double bond of 2), and an alkynyl group having 2 to 30 carbon atoms in total.
The alkyl group represented by R ^{1 to} R ⁶ includes a cycloalkyl group and a bicycloalkyl group, and includes a linear or branched substituted or unsubstituted alkyl group. The linear or branched substituted or unsubstituted alkyl group is preferably an alkyl group having 1 to 30 carbon atoms in total. Examples include methyl, ethyl, n-propyl, isopropyl, tert-butyl, n-octyl, eicosyl, 2-chloroethyl, 2-cyanoethyl, trifluoromethyl, and 2-ethylhexyl. Etc.

  The cycloalkyl group includes a substituted or unsubstituted cycloalkyl group. The substituted or unsubstituted cycloalkyl group is preferably a cycloalkyl group having 3 to 30 carbon atoms in total. Examples include a cyclohexyl group, a cyclopentyl group, and a 4-n-dodecylcyclohexyl group. Furthermore, examples of the bicycloalkyl group include a substituted or unsubstituted bicycloalkyl group having 5 to 30 carbon atoms, that is, a monovalent group obtained by removing one hydrogen atom from a bicycloalkane having 5 to 30 carbon atoms. it can. Examples include a bicyclo [1,2,2] heptan-2-yl group and a bicyclo [2,2,2] octan-3-yl group. Furthermore, a tricyclic structure having a polycyclic structure is also included. The “alkyl group” in the substituents described below includes monocyclic and polycyclic alicyclic hydrocarbon groups in addition to a linear alkyl group and a branched alkyl group in the present invention.

The alkenyl group represented by R ^{1 to} R ⁶ includes a cycloalkenyl group and a bicycloalkenyl group. The alkenyl group represents a substituted or unsubstituted alkenyl group having a linear, branched, or cyclic structure. As the alkenyl group, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms is preferable. Examples include vinyl group, allyl group, prenyl group, geranyl group, and oleyl group.

The cycloalkenyl group is preferably a substituted or unsubstituted cycloalkenyl group having 3 to 30 carbon atoms, that is, a monovalent group in which one hydrogen atom of a cycloalkene having 3 to 30 carbon atoms is removed. Examples include a 2-cyclopenten-1-yl group and a 2-cyclohexen-1-yl group.
The bicycloalkenyl group includes a substituted or unsubstituted bicycloalkenyl group. The bicycloalkenyl group is preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, that is, a monovalent group in which one hydrogen atom of a bicycloalkene having one double bond is removed. Examples include bicyclo [2,2,1] hept-2-en-1-yl group and bicyclo [2,2,2] oct-2-en-4-yl group.

The alkynyl group represented by R ^{1 to} R ⁶ is preferably a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, and examples thereof include an ethynyl group and a propargyl group.

The aryl group represented by R ^{1 to} R ⁶ is preferably an aryl group having 6 to 30 carbon atoms in total, for example, a phenyl group, p-tolyl group, naphthyl group, m-chlorophenyl group, o-hexadecanoylaminophenyl. Groups.

R ^{1 to} R ⁶ in the general formula (1) may have a substituent as much as possible. Examples of the substituent that can be introduced 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, which may be a polycyclic alkyl group such as a bicycloalkyl group or an active methine group), an alkenyl group, an alkynyl group, an aryl group, Heterocyclic group (the position to be substituted may be any or plural), acyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, carbamoyl group (the carbamoyl group having a substituent is, for example, N -Hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarba Yl group, N-sulfamoylcarbamoyl group), carbazoyl group, carboxy group or a salt thereof, oxalyl group, oxamoyl group, cyano group, carbonimidoyl group, formyl group, hydroxy group, alkoxy group (ethyleneoxy group or propyleneoxy group) An aryloxy group, a heterocyclic oxy group, an acyloxy group, an (alkoxy or aryloxy) carbonyloxy group, a carbamoyloxy group, a 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, (alkyl Aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group, sulfamoyl group (substituent sulfamoyl group includes, for example, N-acylsulfamoyl group, N-sulfonylsulfamoyl group), phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, silyl group and the like.
Among these, as R ^{1 to} R ⁶ , an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 18 carbon atoms is preferable from the viewpoint of TEOS polishing rate and scratch, and 1 to 8 carbon atoms. Or an aryl group having 6 to 12 carbon atoms is more preferable.

In the above general formula (1), the divalent linking group represented by L may be an alkylene group having 1 to 30 carbon atoms, an alkenylene group, a cycloalkylene group, an arylene group, or an optionally substituted substituent. A group formed by linking two or more of these divalent linking groups is represented. In addition to the above organic linking group, the linking group represented by L includes —S—, —S (═O) ₂ —, —O—, —C (═O) — in the chain. May be included.
L may have a substituent as much as possible, and examples of the substituent that can be introduced include the same substituents that can be introduced in R ^{1 to} R ⁶ .

Specific examples of the alkylene group having 1 to 30 carbon atoms include methylene group, ethylene group, trimethylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, methylethylene group, and 3-methylpentylene. Group etc. are mentioned, Among these, an ethylene group and a pentylene group are preferable.
Specific examples of the alkenylene group include a vinylene group, a propenylene group, and a butenylene group, and among them, a propenylene group is preferable.
Specific examples of the cycloalkylene group include a cyclohexylene group and a cyclopentylene group. Among them, a cyclohexylene group is preferable.
Specific examples of the arylene group include a phenylene group and a naphthylene group, and among them, a phenylene group is preferable.

In the general formula (1), monovalent or divalent anions represented by nX (2 / n) ⁻ are halogen ions (F ⁻ , Cl ⁻ , Br ⁻ , I ⁻ ), OH ⁻ , BF ₄ ^{−. _{, PF 6 -, CH 3 CO}} 2 -, PhCO 2 -, NO 3 -, SO 4 2-, SO 3 2-, CH 3 SO 3 -, p-CH 3 PhSO 3 -, naphthalene disulfonic acid anion and, A phthalate anion etc. are mentioned.
Here, Ph represents a phenyl group.
Among these, as anions, halogen ions, BF ₄ ⁻ , PF ₆ ⁻ , NO ₃ ⁻ , SO ₄ ²⁻ , CH ₃ SO ₃ ⁻ , and p-CH ₃ PhSO ₃ ⁻ are preferable from the viewpoint of scratch. NO ₃ ⁻ , SO ₄ ²⁻ , CH ₃ SO ₃ ⁻ , and p-CH ₃ PhSO ₃ ⁻ are more preferable.

  Hereinafter, (A) phosphonium salts [Exemplary compounds (A-1) to (A-10)] that can be used in the present invention are exemplified, but the present invention is not limited thereto.

The phosphonium salt (specific cation) in the present invention can be synthesized, for example, by a nucleophilic substitution reaction between a nucleophilic agent such as triallylphosphine or trialkylphosphine and an electrophilic agent such as an alkylating agent.
Moreover, the purchase as a general sale reagent is also possible.

  The amount of the phosphonium salt added in the present invention is the polishing liquid used for polishing (that is, the diluted polishing liquid when the metal polishing composition is diluted with water or an aqueous solution. "Polish" is also agreed.) Is preferably 0.0001 mass% or more and 1 mass% or less, and more preferably 0.001 mass% or more and 0.3 mass% or less. That is, the amount of the specific cation added is preferably 0.0001% by mass or more from the viewpoint of sufficiently improving the polishing rate, and preferably 0.3% by mass or less from the viewpoint of slurry stability.

[(B) Corrosion inhibitor]
The metal polishing composition of the present invention contains a corrosion inhibitor that adsorbs to the surface to be polished to form a film and controls the corrosion of the metal surface. The corrosion inhibitor in the present invention preferably contains a heteroaromatic ring compound having 3 or more nitrogen atoms in the molecule and having a condensed ring structure. Here, the “three or more nitrogen atoms” are preferably atoms constituting a condensed ring. As such a heteroaromatic ring compound, benzotriazole and various substituents are introduced into the benzotriazole. It is preferable that the derivative is

  Examples of corrosion inhibitors that can be used in the present invention include benzotriazole, 1,2,3-benzotriazole, 5,6-dimethyl-1,2,3-benzotriazole, 1- (1,2-dicarboxyethyl) ) Benzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] benzotriazole, 1- (hydroxymethyl) benzotriazole, etc., among which 1,2,3-benzotriazole, 5,6- Dimethyl-1,2,3-benzotriazole, 1- (1,2-dicarboxyethyl) benzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] benzotriazole, and 1- (hydroxymethyl) More preferably, it is selected from benzotriazole.

  The amount of the (B) corrosion inhibitor added is preferably 0.01% by mass or more and 0.2% by mass or less, and more preferably 0.05% by mass or more and 0% by mass with respect to the mass of the polishing liquid used for polishing. More preferably, it is 2% by mass or less. That is, the addition amount of such a corrosion inhibitor is preferably 0.01% by mass or more from the viewpoint of not expanding dishing, and is preferably 0.2% by mass or less from the viewpoint of storage stability.

[(C) colloidal silica]
The metal polishing composition of the present invention contains colloidal silica as at least a part of the abrasive grains. The colloidal silica is preferably colloidal silica that does not contain impurities such as alkali metals inside the particles and is obtained by hydrolysis of alkoxysilane. On the other hand, although colloidal silica produced by a method of removing alkali from an alkali silicate aqueous solution can also be used, in this case, there is a concern that the alkali metal remaining in the particles gradually elutes and affects the polishing performance. . From such a viewpoint, a material obtained by hydrolysis of alkoxysilane is more preferable as a raw material.

The particle diameter of the colloidal silica is appropriately selected according to the purpose of use of the abrasive grains, and is generally about 10 to 200 nm. However, from the viewpoint of not generating polishing scratches, the primary average particle diameter is in the range of 20 to 50 nm. Preferably there is.
The primary average particle diameter of colloidal silica can be measured from a surface area particle diameter or an electron micrograph.

  The content (concentration) of (C) colloidal silica in the metal polishing composition of the present invention is preferably 0.5% by mass or more and 15% by mass or less with respect to the total mass of the polishing liquid when used for polishing. More preferably, it is 3% by mass or more and 12% by mass or less, and particularly preferably 5% by mass or more and 12% by mass or less. That is, the content of (C) colloidal silica is preferably 0.5% by mass or more in terms of polishing the barrier layer at a sufficient polishing rate, and is preferably 15% by mass or less in terms of storage stability.

In the metal polishing composition of the present invention, abrasive grains other than (C) colloidal silica can be used in combination as long as the effects of the present invention are not impaired. In that case, the content ratio of (C) colloidal silica in all abrasive grains is preferably 50% by mass or more, and particularly preferably 80% by mass or more. All of the contained abrasive grains may be (C) colloidal silica.
Examples of abrasive grains that can be used in combination with (C) colloidal silica for the metal polishing composition of the present invention include fumed silica, ceria, alumina, and titania. The size of the abrasive grains used in combination is equal to or more than (C) colloidal silica, and preferably 2 times or less.

  Components other than the above (A), (B), and (C) can be appropriately added to the metal polishing composition of the present invention depending on the purpose. Such additive components will be described.

[(D) Compound having carboxyl group]
The metal polishing composition of the present invention preferably contains (D) a compound having a carboxyl group (hereinafter, appropriately referred to as “organic acid”). The compound having a carboxyl group is not particularly limited as long as it is a compound having at least one carboxyl group in the molecule.
The compound having a carboxyl group is preferably a water-soluble compound, and is exemplified below. Formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid , N-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, Tartaric acid, citric acid, lactic acid, hydroxyethyliminodiacetic acid, iminodiacetic acid, acedamidoiminodiacetic acid, nitrilotripropanoic acid, nitrilotrimethylphosphonic acid and the like.

However, from the viewpoint of the polishing rate structure, it is preferable to select a compound represented by the following general formula (2).
In addition, it is preferable that the number of the carboxyl groups which exist in a molecule | numerator is 1-4, and it is more preferable that it is 1-2 from a viewpoint which can be used cheaply.

In the general formula (2), R ⁷ and R ⁸ each independently represents a hydrocarbon group which may have a substituent, and preferably represents a hydrocarbon group having 1 to 10 carbon atoms in total.
R ⁷ is a monovalent hydrocarbon group which may have a substituent, for example, an alkyl group having 1 to 10 carbon atoms (for example, a methyl group, a cycloalkyl group, etc.), an aryl group (for example, a phenyl group). Etc.), an alkoxy group, an aryloxy group and the like are preferable.
R ⁸ is a divalent hydrocarbon group which may have a substituent, for example, an alkylene group having 1 to 10 carbon atoms (for example, a methylene group, a cycloalkylene group, etc.), an arylene group (for example, a phenylene group). Etc.), an alkyleneoxy group and the like are preferable.

The hydrocarbon group represented by R ⁷ and R ⁸ may have a substituent, and examples of the substituent that can be introduced include an alkyl group having 1 to 3 carbon atoms, an aryl group, an alkoxy group, and a carboxyl group. And the like, and when having a carboxyl group as a substituent, this compound has a plurality of carboxyl groups.
R ⁷ and R ⁸ may be bonded to each other to form a cyclic structure.

Examples of the compound represented by the general formula (2) include 2-furancarboxylic acid, 2,5-furandicarboxylic acid, 3-furancarboxylic acid, 2-tetrahydrofurancarboxylic acid, diglycolic acid, methoxyacetic acid, methoxy Phenylacetic acid, phenoxyacetic acid and the like can be mentioned. Among them, 2,5-furandicarboxylic acid, 2-tetrahydrofurancarboxylic acid, diglycolic acid and methoxyacetic acid are preferable from the viewpoint of polishing the surface to be polished at high speed.
These compounds can be used in combination.

  In the polishing liquid of the present invention, the addition amount of the compound (D) having a carboxyl group (preferably the compound represented by the general formula (2)) is 0 with respect to the mass of the polishing liquid used for polishing. It is preferably 1% by mass or more and 5% by mass or less, and more preferably 0.5% by mass or more and 2% by mass or less. That is, the content of such a compound having a carboxyl group (organic acid) is preferably 0.1% by mass or more in terms of achieving a sufficient polishing rate, and 5% by mass from the point of not causing excessive dishing. The following is preferred.

[(E) Surfactant]
The metal polishing composition of the present invention preferably contains (E) a surfactant. In the metal polishing composition of the present invention, the polishing rate can be improved and the polishing rate of the insulating layer can be controlled by adjusting the type and amount of the surfactant. As the surfactant, an anionic surfactant and a cationic surfactant are particularly preferable.

  Among these, from the viewpoint of improving the polishing rate of the insulating layer, a compound represented by the following general formula (3) is preferable, and from the viewpoint of suppressing the polishing rate of the insulating layer, a compound represented by the following general formula (4) is preferable. preferable. Moreover, it is also possible to use both together.

In the general formula (3), R represents a hydrocarbon group which may have a substituent, and preferably represents a hydrocarbon group having 6 to 20 carbon atoms. Specifically, for example, an alkyl group having 6 to 20 carbon atoms, an aryl group (for example, a phenyl group, a naphthyl group, and the like) are preferable, and the alkyl group and the aryl group further have a substituent such as an alkyl group. It may be. M ⁺ represents a counter cation of sulfonic acid, and preferred are proton, sodium ion, potassium ion, and ammonium ion.

  Specific examples of the compound represented by the general formula (3) include, for example, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, hexadecylbenzenesulfonic acid, dodecylnaphthalenesulfonic acid, tetradecylnaphthalenesulfonic acid. And sodium salts, potassium salts, ammonium salts and the like thereof.

In the general formula (4) ^represents a R a to R ^d each independently of the carbon atoms 1 to 18 which may have a substituent hydrocarbon group. However, R ^{a to} R ^d are not all the same hydrocarbon group.
Examples of the hydrocarbon group represented by R ^{a to} R ^d include an alkyl group, an aryl group, and a phenyl group, and among them, a linear and branched alkyl group having 1 to 20 carbon atoms is preferable.
Two of Ra to Rd may be bonded to each other to form a cyclic structure such as a pyridine structure, a pyrrolidine structure, a piperidine structure, or a pyrrole structure. Y ⁻ represents a counter anion of quaternary ammonium, and preferable ones are OH ⁻ , halogen ion, NO ₃ ⁻ , 1 / 2SO ₄ ²⁻ , CH ₃ CO ₂ ⁻ , CH ₃ SO ₃ ⁻ , p-CH ₃ PhSO ₃ ^-.

Specific examples of the compound represented by the general formula (4) include, for example, OH such as lauryltrimethylammonium, lauryltriethylammonium, stearyltrimethylammonium, palmityltrimethylammonium, octyltrimethylammonium, dodecylpyridinium, decylpyridinium, octylpyridinium, and the like. ^-, halogen _{^{ions, NO 3 -, 1 / 2SO}} 4 2-, CH 3 CO 2 -, CH 3 SO 3 -, p-CH 3 PhSO 3 - and the like.

As the surfactant in the present invention, a compound other than the compound represented by the general formula (3) or (4) may be used. For example, an anionic interface other than the compound represented by the general formula (3) Examples of the activator include carboxylate, sulfate ester salt and phosphate ester salt.
More specifically, as the carboxylate, soap, N-acyl amino acid salt, polyoxyethylene or polyoxypropylene alkyl ether carboxylate, acylated peptide;
Examples of sulfate salts include sulfated oils, alkyl sulfates, alkyl ether sulfates, polyoxyethylene or polyoxypropylene alkyl allyl ether sulfates, alkyl amide sulfates;
As the phosphate ester salt, an alkyl phosphate, polyoxyethylene or polyoxypropylene alkylallyl ether phosphate can be preferably used.

  Nonionic surfactants can also be used. Examples of the nonionic surfactant include ether type, ether ester type, ester type, and nitrogen-containing type. Specifically, polyoxyalkylene alkyl and polyoxyalkylene alkyl phenyl ether (for example, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene are used as the ether type. Higher alcohol ethers, polyoxyethylene myristol ether, polyoxyethylene octyldodecyl ether), polyoxyethylene derivatives (eg, polyoxyethylene disulfonated phenyl ether), polyoxyethylene polyoxypropylene glycol, alkylallyl formaldehyde condensed polyoxyethylene Ether, polyoxyethylene polyoxypropylene block polymer, polyoxyethylene polyoxy Polyoxypropylene alkyl ether, and the like. As ether ester type, polyoxyethylene ether of glycerin ester, polyoxyethylene fatty acid ester (for example, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol distearate, polyoxyethylene hydrogenated castor oil), polyoxyethylene Sorbitan fatty acid esters (for example, polyoxyethylene sorbitan monococonut oil fatty acid ester, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxy Ethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbate Emissions triisostearate, polyoxyethylene sorbitan mono coconut fatty acid ester, polyoxyethylene sorbit tetraoleate), include polyoxyethylene ethers of sorbitol esters. As ester types, sorbitan fatty acid esters (for example, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan sesquioleate), glycerin fatty acid esters (for example Glycerol monostearate, glycerol monooleate), polyglycerol ester, sorbitan ester, propylene glycol ester, sucrose ester and the like. Examples of the nitrogen-containing type include fatty acid alkanolamide (for example, coconut fatty acid diethanolamide), polyoxyethylene alkylamine (for example, polyoxyethylene laurylamine), polyoxyethylene alkylamide (for example, polyoxyethylene lauric acid amide), and the like. It is done. Moreover, a fluorine-type surfactant, an acetylene containing nonionic surfactant (For example, diisobutyl dimethyl butynediol polyoxyethylene glycol ether) etc. are mentioned.

  (E) The addition amount of the surfactant is preferably 0.001 to 10 g, more preferably 0.01 to 5 g in 1 L of a polishing liquid used for polishing as a total amount. It is especially preferable to set it as 0.01-1g. That is, the addition amount of the surfactant is preferably 0.01 g or more in order to obtain a sufficient effect, and is preferably 5 g or less from the viewpoint of preventing a decrease in the CMP rate.

[Body components]
(Oxidant)
The metal polishing composition of the present invention can contain a compound (oxidant) that can oxidize a metal to be polished. Examples of the oxidizing agent include hydrogen peroxide, peroxide, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, persulfate, Examples thereof include dichromate, permanganate, ozone water, silver (II) salt, and iron (III) salt. Among them, hydrogen peroxide is preferably used.
Examples of the iron (III) salt include, in addition to inorganic iron (III) salts such as iron nitrate (III), iron chloride (III), iron sulfate (III), iron bromide (III), and iron (III) Organic complex salts are preferably used.

  The addition amount of the oxidizing agent can be adjusted by the dishing amount at the initial stage of the barrier CMP. When the amount of dishing at the beginning of barrier CMP is large, that is, when it is not desired to polish the wiring material very much in barrier CMP, it is desirable to add a small amount of oxidizer, the dishing amount is sufficiently small, and the wiring material can be removed at high speed. When polishing is desired, it is desirable to increase the addition amount of the oxidizing agent. Thus, since it is desirable to change the addition amount of the oxidizing agent depending on the dishing situation at the initial stage of the barrier CMP, it is preferable that the amount is 0.01 mol to 1 mol in 1 L of the polishing liquid used for polishing. It is especially preferable to set it as 05 mol-0.6 mol.

(PH adjuster)
When using the metal polishing composition of the present invention for polishing, the pH of the polishing liquid is preferably in the range of 2.5 to 5.0, and is preferably in the range of pH 3.0 to 4.5. Is more preferable. By controlling the pH of the polishing liquid within this range, the polishing rate of the interlayer insulating film can be adjusted more significantly.
In order to adjust the pH to the above preferred range, an alkali / acid or a buffer is used. The polishing liquid of the present invention exhibits an excellent effect when the pH is within this range.

  Examples of alkali / acid or buffering agents include non-metallic alkaline agents such as organic ammonium hydroxides such as ammonia, ammonium hydroxide and tetramethylammonium hydroxide, alkanolamines such as diethanolamine, triethanolamine and triisopropanolamine. Alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, inorganic acids such as nitric acid, sulfuric acid and phosphoric acid, carbonates such as sodium carbonate, phosphates such as trisodium phosphate, boric acid Preferable examples include salts, tetraborate and hydroxybenzoate. Particularly preferred alkali agents are ammonium hydroxide, potassium hydroxide, lithium hydroxide and tetramethylammonium hydroxide.

  The addition amount of the alkali / acid or the buffer may be an amount that maintains the pH within a preferable range, and is preferably 0.0001 mol to 1.0 mol in 1 L of the polishing liquid when used for polishing. More preferably, it is 0.003 mol to 0.5 mol.

(Chelating agent)
The metal polishing composition 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.

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

  In general, the metal polishing composition of the present invention is particularly suitable for polishing a barrier layer existing between a wiring made of copper metal and / or a copper alloy and an interlayer insulating film. The barrier layer is made of a barrier metal material to prevent copper diffusion.

[Barrier metal material]
As a material constituting the barrier layer to be polished by the polishing liquid of the present invention, generally a low-resistance metal material is preferable, and TiN, TiW, Ta, TaN, W, WN are particularly preferable, and Ta, TaN are particularly preferable. preferable.

[Interlayer insulation film]
As an interlayer insulating film (insulating layer) to be polished by the metal polishing composition of the present invention, in addition to a commonly used interlayer insulating film such as TEOS, for example, the relative dielectric constant is about 3.5 to 2.0. An interlayer insulating film containing a material having a low dielectric constant (for example, organic polymer type, SiOC type, SiOF type, etc., usually abbreviated as Low-k film) can be given.
Specifically, as a material used for forming a low dielectric constant interlayer insulating film, there are HSG-R7 (Hitachi Chemical Industries), BLACKDIAMOND (Applied Materials, Inc.) and the like in the SiOC system.

  The metal polishing composition of the present invention can improve the polishing rate of the interlayer insulating film (insulating layer) by using the diphosphonium cation and colloidal silica in combination.

[Raw metal materials]
In the present invention, it is preferable that the object to be polished has a wiring made of copper metal and / or copper alloy as applied to a semiconductor device such as LSI. In particular, a copper alloy is preferable as a raw material for the wiring. Furthermore, the copper alloy containing silver is preferable among copper alloys.
In addition, the silver content contained in the copper alloy is preferably 40% by mass or less, particularly 10% by mass or less, more preferably 1% by mass or less, and a copper alloy in the range of 0.00001 to 0.1% by mass. The most excellent effect is exhibited.

[Wiring thickness]
In the present invention, when the object to be polished is applied to, for example, a DRAM device system, it preferably has a wiring with a half pitch of 0.15 μm or less, more preferably 0.10 μm or less, and further Preferably it is 0.08 micrometer or less.
On the other hand, when the object to be polished is applied to, for example, an MPU device system, it is preferable to have a wiring of 0.12 μm or less, more preferably 0.09 μm or less, and still more preferably 0.07 μm or less.
The polishing liquid in the present invention described above exhibits a particularly excellent effect on the object to be polished having such wiring.

[Polishing method]
The metal polishing composition of the present invention comprises: 1. A concentrated liquid which is diluted by adding water or an aqueous solution when used. 2. When each component is prepared in the form of an aqueous solution described in the next section, these are mixed, and if necessary diluted with water to make a working solution. It may be prepared as a working solution.
The polishing liquid in any case can be applied to the polishing method using the metal polishing composition of the present invention.
This polishing method is a method in which a polishing liquid is supplied to a polishing pad on a polishing surface plate and brought into contact with a surface to be polished of an object to be polished so that the surface to be polished and the polishing pad move relative to each other.

  As an apparatus used for polishing, a holder for holding an object to be polished (for example, a wafer on which a conductive material film is formed) having a surface to be polished and a polishing pad are attached (a motor capable of changing the number of rotations). Etc.) and a general polishing apparatus having a polishing surface plate. 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 object to be polished does not pop out. The pressing pressure of the object having the surface to be polished (film to be polished) against the polishing pad is preferably 0.68 to 34.5 KPa, the in-plane uniformity of the object to be polished at the polishing rate and the flatness of the pattern In order to satisfy the properties, it is more preferably 3.40 to 20.7 KPa.

During polishing, the polishing liquid is continuously supplied to the polishing pad with a pump or the like.
After the polishing is finished, the object to be polished is thoroughly washed in running water, and then dried after removing water droplets adhering to the object to be polished using a spin dryer or the like.

In the present invention, the 1. When diluting the concentrated solution as in the above method, the following aqueous solutions can be used. The aqueous solution is water containing at least one of an oxidizing agent, an organic acid, an additive, and a surfactant in advance, and the components contained in the aqueous solution and the concentrated solution to be diluted are contained. A component obtained by summing up the component and the component is used as a component of a polishing liquid (use liquid) used for polishing.
Thus, when the concentrate is diluted with an aqueous solution and used, components that are difficult to dissolve can be added later in the form of an aqueous solution, so that a more concentrated concentrate can be prepared.

  In addition, as a method of diluting by adding water or an aqueous solution to the concentrated liquid, the pipe for supplying the concentrated polishing liquid and the pipe for supplying the water or the aqueous solution are joined together and mixed, and mixed and diluted. There is a method of supplying the used liquid to the polishing pad. Mixing of concentrated liquid with water or aqueous solution is a method in which liquids collide with each other through a narrow passage under pressure, filling the pipe with a filler such as a glass tube, and separating and separating the liquid flow. Ordinary methods such as a method of repeatedly performing and a method of providing a blade rotating with power in the pipe can be employed.

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

  Further, as a method of polishing while diluting the concentrated liquid with water or an aqueous solution, a pipe for supplying the polishing liquid and a pipe for supplying the water or the aqueous solution are provided independently, and a predetermined amount of liquid is respectively applied to the polishing pad. There is a method of supplying and polishing while mixing by the relative motion of the polishing pad and the surface to be polished. It is also possible to use a method in which a predetermined amount of concentrated liquid and water or an aqueous solution are mixed in one container and then the mixed polishing liquid is supplied to the polishing pad for polishing.

In addition, as another polishing method, the component to be contained in the polishing liquid is divided into at least two components, and when these are used, water or an aqueous solution is added and diluted and supplied to the polishing pad on the polishing platen Then, there is a method in which the surface to be polished and the polishing pad are moved relative to each other and brought into contact with the surface to be polished for polishing.
For example, an oxidizer is used as the constituent component (Q1), an organic acid, an additive, a surfactant, and water are used as the constituent component (Q2). The component (Q2) can be diluted and used.
In addition, the low-solubility additive is divided into two components (Q3) and (Q4). For example, an oxidant, an additive, and a surfactant are used as the component (Q3), and an organic acid, an additive, and a surfactant are used. An agent and water are used as the constituent component (Q4), and when they are used, water or an aqueous solution is added to dilute the constituent component (Q3) and the constituent component (Q4).

  In the case of the above example, three pipes for supplying the constituent component (Q1), the constituent component (Q2), and water or an aqueous solution are required, and diluting and mixing requires three pipes to be used as a polishing pad. There is a method in which the pipe is connected to one pipe to be supplied and mixed in the pipe. In this case, it is possible to combine two pipes and then connect another one pipe. Specifically, this is a method in which a constituent component containing an additive that is difficult to dissolve is mixed with another constituent component, a mixing path is lengthened to ensure a dissolution time, and then a water or aqueous solution pipe is further coupled. .

  As described above, the other mixing methods are as follows. The three pipes are directly guided to the polishing pad and mixed by the relative movement of the polishing pad and the surface to be polished, or the three components are mixed in one container. There is a method of supplying diluted polishing liquid to the polishing pad from there.

  In the above polishing method, when one constituent component containing an oxidizing agent is made 40 ° C. or lower and the other constituent components are heated in the range of room temperature to 100 ° C., one constituent component and another constituent component are mixed. Alternatively, when diluting by adding water or an aqueous solution, the liquid temperature can be set to 40 ° C. or lower. This method is a preferable method for increasing the solubility of the raw material having a low solubility of the polishing liquid by utilizing the phenomenon that the solubility becomes high when the temperature is high.

  The raw materials in which the above other components are dissolved by heating in the range of room temperature to 100 ° C. are precipitated in the solution when the temperature is lowered. It is necessary to dissolve the raw material deposited by heating. For this purpose, there are provided means for heating and feeding the other constituents in which the raw materials are dissolved, and means for stirring and feeding the liquid containing the precipitate, and feeding and heating the pipe to dissolve it. Can be adopted. When the temperature of one constituent component containing an oxidizing agent is increased to 40 ° C. or higher, the other constituent components that have been heated may be decomposed. When two components are mixed, it is preferable that the temperature be 40 ° C. or lower.

Thus, in the present invention, the components of the metal polishing composition may be divided into two or more parts and supplied to the surface to be polished. In this case, it is preferable to divide and supply the component containing an oxide and the component containing an organic acid. Alternatively, the polishing liquid may be a concentrated liquid and supplied to the surface to be polished separately from the dilution water.
In the present invention, in the present invention, when applying a method of dividing the components of the metal polishing composition into two or more parts and supplying them to the surface to be polished, the supply amount is the sum of the supply amounts from each pipe Is expressed.

〔pad〕
When polishing with the metal polishing composition of the present invention, 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 be one containing abrasive grains generally used for polishing (for example, ceria, silica, alumina, resin, etc.). 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. As the material, non-woven fabric, artificial leather, polyamide, polyurethane, polyester, polycarbonate and the like are preferable. Further, the surface contacting the surface to be polished may be subjected to processing such as lattice grooves / holes / concentric grooves / helical grooves.

[Wafer]
In the present invention, a wafer as an object to be polished by CMP with the metal polishing composition 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.

[Polishing equipment]
An apparatus capable of performing polishing using the metal polishing composition of the present invention is not particularly limited, but is mira mesa CMP, reflexion CMP (Applied Materials), FREX200, FREX300 (Ebara Seisakusho), NPS3301, NPS2301 (Nikon), A-FP-310A, A-FP-210A (Tokyo Seimitsu), 2300 TERES (Ram Research), Momentum (Speedfam IPEC), etc. can be mentioned.

  Hereinafter, the present invention will be described specifically by way of examples. The present invention is not limited by these examples.

[Example 1]
A polishing liquid having the composition shown below was prepared and a polishing experiment was conducted.
<Composition (1)>
(A) Phosphonium cation: A-1 of the present invention 0.2 g / L
(B) Corrosion inhibitor: benzotriazole (BTA) 0.5 g / L
・ (C) Colloidal silica 200g / L
(Secondary particle size: 65 nm, PL3 slurry, manufactured by Fuso Chemical Industries)
-(D) Compound having a carboxyl group: Diglycolic acid 1 g / L
(Wako Pure Chemical Industries, Ltd.)
-(E) Surfactant: Dodecylbenzenesulfonic acid 0.5 g / L
・ Oxidizing agent: Hydrogen peroxide 10mL
・ Pure water is added and the total volume is 1000mL
pH (adjusted with ammonia water and nitric acid) 3.5

(Evaluation method)
The apparatus “LGP-612” manufactured by Lapmaster Co. was used as a polishing apparatus, and each wafer film shown below was polished while supplying slurry under the following conditions.
・ Table rotation speed: 90rpm
-Head rotation speed: 85rpm
Polishing pressure: 13.79 kPa
Polishing pad: Rotex Nitta Co., Ltd. Polotepad
Polishing liquid supply rate: 200 ml / min

(Polishing rate evaluation: polishing object)
As an object to be polished, an 8-inch wafer in which a Ta film and a TEOS film were formed on a Si substrate was used.

(Scratch evaluation: object to be polished)
As a polishing object, a TEOS (tetraethoxysilane) substrate is patterned by a photolithography process and a reactive ion etching process to form wiring grooves and connection holes having a width of 0.09 to 100 μm and a depth of 600 nm. An 8-inch wafer was used in which a Ta film having a thickness of 20 nm was formed by a tulling method, a copper film having a thickness of 50 nm was subsequently formed by a sputtering method, and then a copper film having a total thickness of 1000 nm was formed by a plating method.

<Polishing speed>
The polishing rate was determined by measuring the film thicknesses of the Ta film (barrier layer) and TEOS film (insulating film) before and after CMP and converting from the following equation. The obtained results are shown in Table 1.
Polishing rate (Å / min) = (film thickness before polishing−film thickness after polishing) / polishing time

<Scratch evaluation>
The polishing object for scratch evaluation was polished to TEOS with the wafer (TEOS film was polished to 50 nm), and then the polished surface was washed with pure water and dried. The dried polished surface was observed with an optical microscope, and scratches were evaluated based on the following evaluation criteria. In addition, (circle) and (triangle | delta) are judged to be a level which does not have a problem practically. The obtained results are shown in Table 1.
-Evaluation criteria-
○: No problem scratches are observed △: One or two problem scratches are observed in the wafer surface ×: Many problem scratches are observed in the wafer surface

[Examples 2 to 14 and Comparative Examples 1 to 3]
Polishing experiment under the same polishing conditions as in Example 1, using a polishing liquid prepared by changing the components (A) to (E) of the composition (1) in Example 1 to the compositions shown in Table 1 below. Went. The results are shown in Table 1.

The (A) phosphonium salt described in Table 1 refers to the aforementioned exemplary compounds.
Details of the compounds abbreviated in Table 1 are shown below.

(B) Corrosion inhibitor BTA: 1,2,3-benzotriazole HABTA: 1- [N, N-bis (hydroxyethyl) aminomethyl] benzotriazole (E) surfactant DBS: dodecylbenzenesulfonic acid

  Further, the shape and primary average particle diameter of (C) colloidal silica C-1 to C-3 shown in Table 1 are shown in Table 2 below. In addition, all the colloidal silicas described in Table 2 are manufactured by Fuso Chemical Industries.

  Moreover, the compound name of the compound (organic acid) D-1 to D-2 which has (D) carboxyl group of Table 1 is shown in following Table 3.

  According to Table 1, when the metal polishing compositions of Examples 1 to 10 of the present invention were used, Ta (barrier layer) and TEOS (interlayer insulating film) were compared with Comparative Example 1 in which no phosphonium salt was added. It can be seen that the polishing rate is high and scratches are not easily scratched.

  From the above, it can be seen that the metal polishing composition of the present invention has high barrier layer polishing rate and excellent scratch performance. Further, it was found that the polishing rate of the interlayer insulating film was also excellent.

Claims (7)

It comprises a diphosphonium salt represented by the following general formula (1), (B) a corrosion inhibitor, and (C) colloidal silica, and is used for chemical mechanical polishing in a semiconductor device manufacturing process. A metal polishing composition.

[In General Formula (1), R ^{1 to} R ⁶ each independently represents an aliphatic hydrocarbon group or an aryl group, and two of R ^{1 to} R ⁶ may be bonded to each other. L represents a divalent linking group, X represents a group that can be a monovalent or divalent anion, and n represents 1 or 2. ]   The metal polishing composition according to claim 1, wherein the metal polishing composition has a pH in the range of 2.5 to 5.0 when used for polishing the metal polishing composition. Furthermore, the metal polishing composition of Claim 1 or Claim 2 containing an oxidizing agent . The (B) corrosion inhibitor is 1,2,3-benzotriazole, 5,6-dimethyl-1,2,3-benzotriazole, 1- (1,2-dicarboxyethyl) benzotriazole, 1- [ The compound according to any one of claims 1 to 3 , which is at least one compound selected from the group consisting of N, N-bis (hydroxyethyl) aminomethyl] benzotriazole and 1- (hydroxymethyl) benzotriazole. The metal polishing composition as described. The metal polishing composition according to any one of claims 1 to 4 , wherein a concentration of the (C) colloidal silica is 0.5 to 15% by mass with respect to a total mass of the metal polishing composition. . Furthermore, the metal polishing composition of any one of Claims 1-5 containing the compound which has (D) carboxyl group. A metal polishing composition according to any one of claims 1 to 6 is supplied to a polishing pad on a polishing platen, and the polishing pad is brought into contact with a surface to be polished of a body to be polished. A metal polishing method by relatively moving a surface and a polishing pad.