JP2007273910A - Polishing composition liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing composition matter having superior dishing performance while maintaining a high polishing speed. <P>SOLUTION: This polishing composition liquid comprises following (a)-(c): (a) colloidal silica particles whose surface of silicon atom is partially coated with aluminum atoms; (b) a kind or more particles whose surface is charged with positive charges; and (c) water. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polishing composition liquid, and more particularly to a polishing composition liquid used in a wiring process in semiconductor device manufacturing.

  In the development of semiconductor devices typified by semiconductor integrated circuits (hereinafter referred to as “LSI” where appropriate), in recent years, miniaturization and stacking of wiring has led to higher density and higher integration for miniaturization and higher speed. It has been demanded. For this purpose, various techniques such as chemical mechanical polishing ((Chemical Mechanical Polishing, hereinafter referred to as “CMP” as appropriate)) have been used, which is used for processing a film to be processed such as an interlayer insulating film. This technique is essential when performing surface planarization, plug formation, formation of embedded metal wiring, etc., and this technique is used to smooth the substrate and remove excess metal thin film during wiring formation (for example, , See Patent Document 1).

  A general method of CMP is to apply a polishing pad on a circular polishing platen (platen), immerse the surface of the polishing pad with a polishing liquid, press the surface of the substrate (wafer) against the pad, In a state where pressure (polishing pressure) is applied, both the polishing platen and the substrate are rotated, and the surface of the substrate is flattened by the generated mechanical friction.

  Conventionally, tungsten and aluminum have been widely used in interconnect structures as wiring metals. However, LSIs using copper, which has lower wiring resistance than these metals, have been developed with the aim of achieving higher performance. As a method for wiring this copper, a damascene method is known (for example, see Patent Document 2). Further, a dual damascene method in which a contact hole and a wiring trench are simultaneously formed in an interlayer insulating film and a metal is embedded in both has been widely used. As a target material for copper wiring, a high-purity copper target of five nines or more has been shipped.

  However, in recent years, with the miniaturization of wiring aiming at further higher density, it has become necessary to improve the conductivity and electronic characteristics of copper wiring, and accordingly, a copper alloy in which a third component is added to high-purity copper is required. It is also beginning to be considered for use. At the same time, there is a need for high-speed metal polishing means that can exhibit high productivity without contaminating these high-definition and high-purity materials. In copper metal polishing, because it is a particularly soft metal, only the center is polished deeper and a dish-like dent is formed (dishing), and the surface of a plurality of wiring metal surfaces forms a dish-shaped recess. (Erosion) and polishing scratches (scratches) are likely to occur, and a highly accurate polishing technique is increasingly required.

Furthermore, in recent years, the wafer diameter at the time of manufacturing LSIs has been increased to improve productivity. Currently, the diameter of 200 mm or more is widely used, and the manufacture of 300 mm or more has 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 occur, and the demand for uniformity of polishing within the wafer surface has become increasingly severe.
A chemical polishing method is known in which mechanical polishing means is not applied to copper and copper alloys (see, for example, Patent Document 3). However, the chemical polishing method using only the chemical dissolution action has a greater problem in flatness due to the occurrence of dishing of the recess, that is, the occurrence of dishing, as compared with CMP in which the metal film of the protrusion is selectively chemically and mechanically polished. Remaining.

  In addition, when copper wiring is used in LSI manufacturing, a diffusion preventing layer called a barrier layer is generally provided between the wiring portion and the insulating layer in order to prevent copper ions from diffusing into the insulating material. The barrier layer is formed of one or more layers made of a barrier material selected from TaN, TaSiN, Ta, TiN, Ti, Nb, W, WN, Co, Zr, ZrN, Ru, and CuTa alloy. Since these barrier materials themselves have conductive properties, the barrier material on the insulating layer must be completely removed in order to prevent the occurrence of errors such as leakage current. This removal processing is achieved by a method similar to the bulk polishing of the metal wiring material (barrier CMP).

  Further, in bulk polishing of copper, dishing is likely to occur particularly in a wide metal wiring portion. Therefore, in order to achieve final planarization, it is desirable to be able to adjust the amount of polishing and removal in the wiring portion and the barrier portion. For this reason, it is desired that the polishing liquid for barrier polishing has an optimum copper / barrier metal polishing selectivity. 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 liquid (polishing composition liquid) used for CMP generally contains solid abrasive grains (for example, alumina, silica) and an oxidizing agent (for example, hydrogen peroxide, persulfuric acid). It is considered that the basic mechanism of CMP using such a polishing composition liquid is polishing by oxidizing the metal surface with an oxidizing agent and removing the oxide film with abrasive grains (for example, non-polishing). (See Patent Document 1).

  However, when CMP is performed using a polishing composition liquid containing such solid abrasive grains, it contains solid abrasive grains in a cleaning process usually performed to remove the polishing liquid remaining on the semiconductor surface after polishing. The use of the polishing liquid complicates the cleaning process, and there is a problem in terms of cost, for example, it is necessary to separate the solid content in order to process the liquid (waste liquid) after the cleaning.

  As one means for solving these problems, for example, a metal surface polishing method using a combination of a polishing liquid not containing abrasive grains and dry etching is disclosed (for example, see Non-Patent Document 2). A polishing composition liquid composed of / malic acid / benzotriazole / ammonium polyacrylate and water is disclosed (for example, see Patent Document 4). According to these methods, the metal film on the convex portion of the semiconductor substrate is selectively CMPed, and the metal film is left in the concave portion to obtain a desired conductor pattern. Since CMP proceeds by friction with a polishing pad that is much mechanically softer than that containing conventional solid abrasive grains, the occurrence of scratches is reduced. However, due to a decrease in physical polishing power, there is a drawback that it is difficult to obtain a sufficient polishing rate and that a metal residue is generated.

On the other hand, a polishing liquid containing abrasive grains has a feature that a high polishing rate is obtained and metal polishing clearness is good, but there is a problem that dishing proceeds or scratches occur due to inclusion of abrasive grains. was there.
US Pat. No. 4,944,836 JP-A-2-278822 JP 49-122432 A JP 2001-127019 A Journal of Electrochemical Society, 1991, 138, 11, 3460-3464 Journal of Electrochemical Society, 2000, 147, 10, 3907-3913

  An object of the present invention is to provide a polishing composition having excellent dishing performance while maintaining a high polishing rate.

As a result of intensive studies on the problems related to the metal polishing composition liquid, the present inventors have found that the problems can be solved by the following polishing composition liquid, and have completed the present invention.
That is, the present invention is as follows.

<1> A polishing composition liquid comprising the following (a) to (c).
(A) Colloidal silica particles in which at least a part of the surface silicon atoms are covered with aluminum atoms (b) One or more types of particles whose surface is positively charged (c) Water <2> Said (b The polishing composition liquid according to <1>, wherein the one or more types of particles having a positively charged surface include colloidal silica.
<3> The (b) one or more kinds of particles whose surfaces are positively charged include colloidal silica in which at least a part of the surface is modified with an aminosilane coupling agent < Polishing composition liquid as described in 1> or <2>.

<4> One or more types of particles (b) whose surface is positively charged are polystyrene and styrene copolymers, methacrylic resins or acrylic resins and copolymers thereof, polyvinyl chloride, polyacetal, saturated The polishing composition liquid according to <1>, comprising at least one selected from the group consisting of polyester, polyamide, polyimide, polycarbonate, phenoxy resin, polyethylene, polypropylene, polyolefin, and polyvinylbenzene.
<5> The average primary particle diameter of colloidal silica particles in which at least part of silicon atoms on the surface (a) is covered with aluminum atoms is in the range of 20 nm to 400 nm, and (b) one or more types of surfaces <1>-<4> The polishing composition liquid according to any one of <1> to <4>, wherein an average primary particle diameter of particles positively charged is in the range of 3 nm to 90 nm.
<6> The average primary particle diameter of colloidal silica particles in which at least a part of silicon atoms on the surface (a) is covered with aluminum atoms is in the range of 3 nm to 90 nm, and (b) one or more types of surfaces <1>-<4> The polishing composition liquid according to any one of <1> to <4>, wherein an average primary particle size of particles positively charged is in the range of 20 nm to 400 nm.
<7> The polishing composition liquid according to any one of <1> to <6>, wherein the pH is adjusted to a range of 2 to 9.5.

  According to the present invention, it is possible to provide a polishing composition liquid excellent in dishing performance while maintaining a high polishing rate.

[Polishing composition liquid]
The polishing composition liquid of the present invention contains (a) to (c) described below.
(A) Colloidal silica particles in which at least some of the silicon atoms on the surface are covered with aluminum atoms (b) One or more types of particles whose surface is positively charged (c) Water

<(A) Colloidal silica particles in which at least part of silicon atoms on the surface are covered with aluminum atoms>
The colloidal silica particles in which at least some of the silicon atoms on the surface used in the present invention are covered with aluminum atoms function as abrasive grains in the metal polishing slurry of the present invention. These are referred to as specific colloidal silica particles as appropriate.
In the present invention, “a colloidal silica particle in which at least a part of the surface silicon atoms are covered with aluminum atoms” means that the aluminum atoms are present on the surface of the colloidal silica having sites containing silicon atoms having a coordination number of 4. In which the aluminum atom having four oxygen atoms coordinated is bonded to the surface of the colloidal silica, and a new surface in which the aluminum atom is fixed in a four-coordinate state is formed. Alternatively, the silicon atoms present on the surface may be once extracted and a new surface covered with aluminum atoms may be generated.

  The colloidal silica used for the preparation of the specific colloidal silica particles is more preferably colloidal silica having a very low content of impurities such as alkali metals inside the particles and obtained by hydrolysis of high-purity 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. Therefore, from such a viewpoint, a material obtained by hydrolysis of the alkoxysilane is more preferable as a raw material.

  The particle size of the colloidal silica used as a raw material is appropriately selected according to the purpose of use of the abrasive grains, but is generally about 3 to 400 nm, preferably 5 to 150 nm, and more preferably 9 to 120 nm. is there.

As a method for obtaining a specific colloidal silica by substituting silicon atoms on the surface of such colloidal silica particles with an aluminum atom, for example, a method of adding an aluminate compound such as ammonium aluminate to a dispersion of colloidal silica is preferably used. More specifically, the silica sol obtained by adding the aqueous alkali aluminate solution is heated at 80 to 250 ° C. for 0.5 to 20 hours, and the cation exchange resin or anion exchange with the cation exchange resin is performed. A method of contacting a resin, a method of adding an acidic silicic acid solution and an aluminum compound aqueous solution to a SiO ₂ -containing alkaline aqueous solution or alkali metal hydroxide aqueous solution, or an acidic silicic acid solution containing an aluminum compound mixed with a SiO ₂ -containing alkaline aqueous solution or alkaline metal water Aluminum prepared by a method of adding to an aqueous oxide solution A method of dealkalizing a compound-containing alkaline silica sol with a cation exchange resin is mentioned. These methods are described in detail in Japanese Patent No. 3463328 and Japanese Patent Laid-Open No. 63-123807, and this description can be applied to the present invention.

As another method, a method of adding aluminum alkoxide to a dispersion of colloidal silica can be mentioned.
The aluminum alkoxide used here may be any, but is preferably aluminum isopropoxide, aluminum butoxide, aluminum methoxide, or aluminum ethoxide, and particularly preferably aluminum isopropoxide or aluminum butoxide.

  Specific colloidal silica particles are acidic by the aluminosilicate site generated by the reaction between tetracoordinate aluminate ions and silanol groups on the surface of the colloidal silica fixing negative charges, giving the particles a large negative zeta potential. Is also excellent in dispersibility. Therefore, it is important that the specific colloidal silica particles produced by the method as described above exist in a state where an aluminum atom is coordinated to four oxygen atoms.

  Such a structure, that is, the occurrence of substitution of silicon atoms and aluminum atoms on the colloidal silica surface can be easily confirmed, for example, by measuring the zeta potential of the abrasive grains.

The amount of substitution of silicon atoms on the surface of colloidal silica with aluminum atoms is preferably such that the surface atom substitution rate (number of introduced aluminum atoms / number of surface silicon atom sites) of colloidal silica is 0.001% or more and 20% or less. Is from 0.01% to 10%, particularly preferably from 0.1% to 5%.
When the silicon atom on the surface of the colloidal silica is replaced with an aluminum atom, the substitution amount with the aluminum atom is controlled by controlling the addition amount (concentration) of an aluminate compound, aluminum alkoxide, etc. added to the colloidal silica dispersion. It can be appropriately controlled.

Here, the amount of aluminum atoms introduced into the colloidal silica surface (number of introduced aluminum atoms / number of surface silicon atom sites) is consumed from the unreacted aluminum compound remaining after the reaction among the aluminum compounds added to the dispersion. The amount of the obtained aluminum compound was calculated, assuming that they reacted 100%, the surface area converted from the colloidal silica diameter, the specific gravity of colloidal silica 2.2, and the number of silanol groups per unit surface area (5-8 pieces / nm ²⁾ it can be estimated from actual measurements obtained specific colloidal silica per se and elemental analysis, aluminum is not present inside the particles, assuming spread uniformly and thinly on the surface, the colloidal silica The surface area / specific gravity and the number of silanol groups per unit surface area are obtained.

As a specific production method, for example, colloidal silica is dispersed in water in the range of 1 to 50% by mass, a pH adjuster is added to the dispersion to adjust the pH to 7 to 11, and then at around room temperature, Add aqueous ammonium aluminate and stir at that temperature for 1-10 hours. Then, the method of removing an impurity by ion exchange, ultrafiltration, etc., and obtaining specific colloidal silica is mentioned.
The average primary particle diameter of the obtained specific colloidal silica particles is preferably 3 to 400 nm, more preferably 5 to 150 nm, and particularly preferably 9 to 120 nm.

  The content of the specific colloidal silica particles in the polishing liquid when using the polishing composition liquid is preferably 0.001% by mass to 10% by mass, and more preferably 0.01% by mass to 0.5% by mass. Especially preferably, it is 0.01 mass% or more and 6 mass% or less.

<(B) One or more types of particles whose surface is positively charged>
The one or more kinds of particles whose surfaces are positively charged include, for example, means for adsorbing ammonia or ammonium salt on the surface of inorganic particles or organic particles, coupling treatment with a coupling agent having an amino group at the end, The particles can be charged to a positive charge by means of forming the surface of the particles by grafting so that the surface has an amino group at the terminal, or by means of handling the particles in a pH region below the equipotential point.

As the coupling treatment, a coupling treatment using an aminosilane coupling agent is particularly desirable, and commercially available aminosilane coupling agents (for example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2 (aminoethyl) are used. ) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, and the like) are simply treated by an integral blend method. be able to.
Further, the grafting treatment can be obtained, for example, by applying the grafting treatment described in Japanese Patent No. 2729850 to the surface of inorganic particles or organic particles.

  It is particularly preferable that the inorganic particles or the organic particles constituting the particles having a positively charged surface include colloidal silica. The content of colloidal silica in the entire particles having a positively charged surface when containing colloidal silica is preferably 10% by mass or more, and more preferably 25% by mass or more.

  In addition, it is preferable that at least a part of the surface of the colloidal silica as the inorganic particles or organic particles constituting the particles having positively charged surfaces is surface-modified with an aminosilane coupling agent. Examples of the aminosilane coupling agent in this case include the aminosilane coupling agents described above.

  On the other hand, inorganic particles and organic particles constituting the particles whose surface is charged to a positive charge are polystyrene and styrene copolymers, methacrylic resins such as polymethacrylate or acrylic resins and copolymers thereof, polyvinyl chloride, It is preferable to include at least one selected from the group consisting of polyacetal, saturated polyester, polyamide, polyimide, polycarbonate, phenoxy resin, polyethylene, polypropylene, polyolefin, and polyvinylbenzene, and among them, polystyrene, acrylic resin, divinylbenzene, and a combination thereof. It is preferable to contain a polymer.

  The average primary particle diameter of the particles whose surface is positively charged is preferably 3 to 400 nm, more preferably 9 to 320 nm, and still more preferably 20 to 820 nm.

  In the polishing composition liquid of the present invention, the average primary particle diameter of the colloidal silica particles in which at least part of the silicon atoms on the surface (a) is covered with aluminum atoms is in the range of 20 nm to 400 nm, ) It is preferable that the average primary particle diameter of one or more kinds of particles whose surface is positively charged is in the range of 3 nm to 90 nm. The average primary particle diameter of the colloidal silica particles in which at least a part of silicon atoms on the surface (a) is covered with aluminum atoms is in the range of 3 nm to 90 nm, and (b) one or more types of surfaces are The average primary particle diameter of the positively charged particles is preferably in the range of 20 nm to 400 nm.

  The particles having a positively charged surface are considered to be hetero-aggregated in the polishing composition liquid because they have a reverse charge to the specific colloidal silica, and (a) at least of silicon atoms on the surface A scanning electron micrograph of the polishing composition liquid of the present invention containing colloidal silica particles partially covered with aluminum atoms, and (b) one or more kinds of particles having a positively charged surface. When observed, it can be confirmed that both particles are adsorbed with high selectivity.

  The surface potential of the particles whose surface is charged to a positive charge can be easily measured with a ζ potentiometer (manufactured by Otsuka Electronics Co., Ltd., ELS-Z1) in the state of an aqueous slurry. At the time of measurement, the condition that at least the specific colloidal silica having a negative charge is not contained is necessary for accurate measurement of the surface potential of “one or more kinds of particles whose particle surface is positively charged”. The surface potential of particles having a positively charged surface used in the present invention is preferably from +3 mV to +100 mV, and more preferably from +5 mV to +90 mV in terms of controllability of heteroaggregation.

  Hetero-aggregated particles formed by the colloidal silica and particles whose surface is positively charged have a large specific surface area compared to the particle diameter, and at the time of hetero-aggregation, a high polishing rate is obtained, and polishing is involved. It is considered that the number of particles re-participating in the polishing is increased by removing the heteroaggregation later, and the surface to be polished can be removed more uniformly. By removing the surface to be polished uniformly, for example, in the CMP of metal wiring, the clearness of the metal to be removed becomes good, and polishing can be finished at a point earlier than before, which seems to lead to reduction of dishing. It is.

  The content of the particles whose surface is positively charged in the polishing liquid when using the polishing composition liquid is preferably 0.001% by mass or more and 50% by mass or less, more preferably 0.03% by mass. It is 20 mass% or less.

(Abrasive grains)
In the present invention, in addition to (a) colloidal silica particles in which at least part of silicon atoms on the surface is covered with aluminum atoms, and (b) one or more kinds of particles whose surface is charged to a positive charge, the following: Abrasive grains can be included. That is, oxides such as aluminum oxide, cerium oxide, titanium oxide, silicon oxide, silicon nitride, silicon carbide, aluminum nitride, methacrylic resins such as polystyrene and styrene copolymers, polymethacrylates or acrylic resins, and copolymers thereof , Polyvinylbenzene, polyvinyl chloride, polyacetal, saturated polyester, polyamide, polyimide, polycarbonate, phenoxy resin, polyethylene, polypropylene, polyolefin, and an organic polymer composed of a copolymer thereof.

  Such (a) colloidal silica particles in which at least some of the silicon atoms on the surface are covered with aluminum atoms, and (b) one or more types of abrasive grains other than particles having a positively charged surface. The total content is preferably 50% by mass or less, and more preferably 20% by mass or less in the polishing liquid when the polishing composition liquid is used.

(Heterocyclic compound)
The polishing composition liquid of the present invention can contain a heterocyclic compound as a function of forming a passive film on a metal when the metal is included in the object to be polished.

  Here, the “heterocyclic compound” is a compound having a heterocyclic ring containing one or more heteroatoms. A hetero atom means an atom other than a carbon atom or a hydrogen atom. A heterocycle means a cyclic compound having at least one heteroatom. A heteroatom means only those atoms that form part of a heterocyclic ring system, either external to the ring system, separated from the ring system by at least one non-conjugated single bond, Atoms that are part of a further substituent of are not meant.

  A hetero atom is preferably a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, and a boron atom, and more preferably a nitrogen atom, a sulfur atom, an oxygen atom, and a selenium atom. And particularly preferably a nitrogen atom, a sulfur atom and an oxygen atom, and most preferably a nitrogen atom and a sulfur atom.

First, the heterocyclic ring that is the mother nucleus is described.
The number of members of the heterocyclic ring of the heterocyclic compound used in the present invention is not particularly limited, and may be a monocyclic compound or a polycyclic compound having a condensed ring. The number of members in the case of a single ring is preferably 3 to 8, more preferably 5 to 7, and particularly preferably 5 and 6. Further, the number of rings in the case of having a condensed ring is preferably 2 to 4, and more preferably 2 or 3.

Specific examples of these heterocyclic rings include the following. However, it is not limited to these.
Pyrrole ring, thiophene ring, furan ring, pyran ring, thiopyran ring, imidazole ring, pyrazole ring, thiazole ring, isothiazole ring, oxazole ring, isoxazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, pyrrolidine ring, Pyrazolidine ring, imidazolidine ring, isoxazolidine ring, isothiazolidine ring, piperidine ring, piperazine ring, morpholine ring, thiomorpholine ring, chroman ring, thiochroman ring, isochroman ring, isothiochroman ring, indoline ring, isoindoline ring, pyringin Ring, indolizine ring, indole ring, indazole ring, purine ring, quinolidine ring, isoquinoline ring, quinoline ring, naphthyridine ring, phthalazine ring, quinoxaline ring, quinazoline ring, cinnoline ring, pteridine ring, acridine Perimidine ring, phenanthroline ring, carbazole ring, carboline ring, phenazine ring, anti-lysine ring, thiadiazole ring, oxadiazole ring, triazine ring, triazole ring, tetrazole ring, benzimidazole ring, benzoxazole ring, benzthiazole ring, benz A thiadiazole ring, a benzfuroxan ring, a naphthimidazole ring, a benztriazole ring, a tetraazaindene ring and the like are mentioned, and a triazole ring and a tetrazole ring are more preferred.

Next, substituents that the heterocyclic ring may have will be described.
In the present invention, when a specific moiety is referred to as a “group”, the moiety may be unsubstituted or substituted with one or more (up to the maximum possible) substituents. Means good. For example, “alkyl group” means a substituted or unsubstituted alkyl group.

Examples of the substituent that can be used in the heterocyclic compound used in the present invention include the following.
However, it is not limited to these.
Halogen atom (fluorine atom, chlorine atom, bromine atom or iodine atom), alkyl group (straight chain, branched or cyclic alkyl group, and active methine group even if it is a polycyclic alkyl group such as a bicycloalkyl group) ), Alkenyl group, alkynyl group, aryl group, heterocyclic group (regarding the position of substitution), acyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, carbamoyl group (substituent) Examples of the carbamoyl group having an N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group), carbazoyl group, carboxy Group or a salt thereof, oxalyl group, oxamoy Group, cyano group, carbonimidoyl group, formyl group, hydroxy group, alkoxy group (including groups containing ethyleneoxy group or propyleneoxy group unit repeatedly), aryloxy group, heterocyclic oxy group, acyloxy group, (alkoxy or Aryloxy) carbonyloxy group, carbamoyloxy group, 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, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfoni Ureido group, N-acylureido group, N-acylsulfamoylamino group, hydroxyamino group, nitro group, heterocyclic group containing a quaternized nitrogen atom (for example, pyridinio group, imidazolio group, quinolinio group, isoquinolinio group) , Isocyano group, imino group, mercapto group, (alkyl, aryl, or heterocyclic) thio group, (alkyl, aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, Sulfo group or a salt thereof, sulfamoyl group (for example, N-acylsulfamoyl group, N-sulfonylsulfamoyl group) or a salt thereof, phosphino group, phosphinyl group, phosphinyloxy group Phosphinylamino group, silyl group, etc. Can be mentioned.

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

  Among these, preferable substituents include, for example, halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, or iodine atoms), alkyl groups (straight chain, branched or cyclic alkyl groups, and polycyclic groups such as bicycloalkyl groups). An alkyl group or an active methine group), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (regarding the position of substitution), an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, hetero Ring oxycarbonyl group, carbamoyl group, N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group, carbazoyl group, oxalyl group, Oxamoyl group, cyano group, carboximide Group, formyl group, hydroxy group, alkoxy group (including groups containing ethyleneoxy group or propyleneoxy group units), aryloxy group, heterocyclic oxy group, acyloxy group, (alkoxy or aryloxy) carbonyloxy group, Carbamoyloxy group, sulfonyloxy 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, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfonylureido group, N-acylureido group, N- A silsulfamoylamino group, a 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 or a salt thereof, sulfamoyl group, N- Examples include acylsulfamoyl group, N-sulfonylsulfamoyl group or a salt thereof, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, silyl group and the like. Here, the active methine group means a methine group substituted with two electron-withdrawing groups, and the electron-withdrawing group here means an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an alkyl group. Examples include a sulfonyl group, an arylsulfonyl group, a sulfamoyl group, a trifluoromethyl group, a cyano group, a nitro group, and a carbonimidoyl group.

  More preferably, for example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched or cyclic alkyl group, and a polycyclic alkyl group such as a bicycloalkyl group) And may contain an active methine group), an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group (regarding the position of substitution).

  In addition, two of the above substituents can jointly form a ring (aromatic or non-aromatic hydrocarbon ring or heterocyclic ring), which are further combined to form a polycyclic fused ring. can do. For example, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, triphenylene ring, naphthacene ring, biphenyl ring, pyrrole ring, furan ring, thiophene ring, imidazole ring, oxazole ring, thiazole ring, pyridine ring, pyrazine ring, pyrimidine Ring, pyridazine ring, indolizine ring, indole ring, benzofuran ring, benzothiophene ring, isobenzofuran ring, quinolidine ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinoxazoline ring, isoquinoline ring, carbazole ring, phenanthridine Ring, acridine ring, phenanthroline ring, thianthrene ring, chromene ring, xanthene ring, phenoxathiin ring, phenothiazine ring, and phenazine ring. ) Can also be formed.

  Specific examples of the heterocyclic compound that can be particularly preferably used in the present invention include, but are not limited to, the following. That is, 1,2,3,4-tetrazole, 5-amino-1,2,3,4-tetrazole, 5-methyl-1,2,3,4-tetrazole, 1,2,3-triazole, 4- Amino-1,2,3-triazole, 4,5-diamino-1,2,3-triazole, 1,2,4-triazole, 3-amino1,2,4-triazole, 3,5-diamino-1 2,4-triazole.

The content of the heterocyclic compound in the polishing composition liquid of the present invention is preferably 0.001 to 1.0% by mass, more preferably 0.001 to 0.7% by mass, and 0.002 More preferably, it is -0.4 mass%.
It is preferable that the content of the heterocyclic compound is within the range of 0.001 to 1.0% by mass because the balance between the polishing rate, the dishing amount, and the cost becomes good.

(Oxidant)
The polishing composition liquid of the present invention preferably contains a compound (oxidant) capable of oxidizing the metal to be polished.
Examples of the oxidizing agent include hydrogen peroxide, peroxide, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, persulfate, Bichromate, permanganate, ozone water and silver (II) salt, iron (III) salt are mentioned.
Examples of iron (III) salts include inorganic iron (III) salts such as iron nitrate (III), iron chloride (III), iron sulfate (III), iron bromide (III), and organic iron (III) salts. Complex salts are preferably used.

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

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

Among them, hydrogen peroxide, iodate, hypochlorite, chlorate, persulfate, and an organic complex salt of iron (III) are preferable, and a preferable complex-forming compound when an organic complex salt of iron (III) is used is Citric acid, tartaric acid, aminopolycarboxylic acid (specifically, ethylenediamine-N, N, N ′, N′-tetraacetic acid, diethylenetriaminepentaacetic acid, 1,3-diaminopropane-N, N, N ′, N '-Tetraacetic acid, ethylenediamine-N, N'-disuccinic acid (racemic), ethylenediaminedisuccinic acid (SS), N- (2-carboxylateethyl) -L-aspartic acid, N- (carboxymethyl)- L-aspartic acid, β-alanine diacetic acid, methyliminodiacetic acid, nitrilotriacetic acid, iminodiacetic acid).
Among the oxidizing agents, hydrogen peroxide, persulfate, and iron (III) ethylenediamine-N, N, N ′, N′-tetraacetic acid, 1,3-diaminopropane-N, N, N ′, N′— Most preferred is a complex of tetraacetic acid and ethylenediamine disuccinic acid (SS form).

  The addition amount of the oxidizing agent is preferably 0.003 mol to 8 mol, more preferably 0.03 mol to 6 mol, and more preferably 0.1 mol to 4 mol, per liter of the polishing composition liquid used for polishing. It is particularly preferable to do this. That is, the addition amount of the oxidizing agent is preferably 0.003 mol or more from the viewpoint of sufficient metal oxidation and ensuring a high CMP rate, and is preferably 8 mol or less from the viewpoint of preventing roughening of the polished surface.

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

As cationic surfactant, aliphatic amine salt, aliphatic quaternary ammonium salt, benzalkonium chloride salt, benzethonium chloride, pyridinium salt, imidazolinium salt; as amphoteric surfactant, carboxybetaine type, sulfobetaine type, Mention may be made of aminocarboxylates, imidazolinium betaines, lecithins, alkylamine oxides.
Nonionic surfactants include ether type, ether ester type, ester type and nitrogen-containing type. Ether type includes polyoxyethylene alkyl and alkylphenyl ether, alkylallyl formaldehyde condensed polyoxyethylene ether, polyoxyethylene poly Examples include oxypropylene block polymer, polyoxyethylene polyoxypropylene alkyl ether, ether ester type, glycerin ester polyoxyethylene ether, sorbitan ester polyoxyethylene ether, sorbitol ester polyoxyethylene ether, ester type, Polyethylene glycol fatty acid ester, glycerin ester, polyglycerin ester, sorbitan ester, propylene glycol ester Le, sucrose esters, nitrogen-containing type, fatty acid alkanolamides, polyoxyethylene fatty acid amides, polyoxyethylene alkyl amide, and the like.
In addition, a fluorine-type surfactant etc. are mentioned.

  As the surfactant, an anionic surfactant or a nonionic surfactant is preferable, and as the salt, ammonium salt, potassium salt, sodium salt and the like can be mentioned, and ammonium salt and potassium salt are particularly preferable.

  Furthermore, other surfactants, hydrophilic compounds, hydrophilic polymers and the like include esters such as glycerin ester, sorbitan ester, methoxyacetic acid, ethoxyacetic acid, 3-ethoxypropionic acid and alanine ethyl ester; polyethylene glycol, polypropylene glycol, Polytetramethylene glycol, polyethylene glycol alkyl ether, polyethylene glycol alkenyl ether, alkyl polyethylene glycol, alkyl polyethylene glycol alkyl ether, alkyl polyethylene glycol alkenyl ether, alkenyl polyethylene glycol, alkenyl polyethylene glycol alkyl ether, alkenyl polyethylene glycol alkenyl ether, polypropylene glycol alkyl Ete , Polypropylene glycol alkenyl ethers, alkyl polypropylene glycols, alkyl polypropylene glycol alkyl ethers, alkyl polypropylene glycol alkenyl ethers, alkenyl polypropylene glycols, alkenyl polypropylene glycol alkyl ethers and alkenyl polypropylene glycol alkenyl ethers; alginic acid, pectinic acid, carboxymethylcellulose, curd Polysaccharides such as orchid and pullulan; amino acid salts such as glycine ammonium salt and glycine sodium salt; polyaspartic acid, polyglutamic acid, polylysine, polymalic acid,

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

  However, when the substrate to be applied is a silicon substrate for a semiconductor integrated circuit or the like, contamination with an alkali metal, an alkaline earth metal, a halide, or the like is not desirable, so an acid or an ammonium salt thereof is desirable. This is not the case when the substrate is a glass substrate or the like. Among the above exemplified compounds, cyclohexanol, polyacrylic acid ammonium salt, polyvinyl alcohol, succinic acid amide, polyvinyl pyrrolidone, polyethylene glycol, and polyoxyethylene polyoxypropylene block polymer are more preferable.

The addition amount of the surfactant and / or the hydrophilic polymer is preferably 0.001 to 10 g, and preferably 0.01 to 5 g in 1 L of the polishing composition liquid when used for polishing as a total amount. Is more preferably 0.1 to 3 g. That is, the addition amount of the surfactant and / or the hydrophilic polymer is preferably 0.001 g or more for obtaining a sufficient effect, and is preferably 10 g or less from the viewpoint of preventing the CMP rate from being lowered. Moreover, as a weight average molecular weight of these surfactant and / or hydrophilic polymer, 500-100000 are preferable, and 2000-50000 are especially preferable.
Only one type of surfactant may be used, two or more types may be used, and different types of surfactants may be used in combination.

(Quaternary alkyl ammonium compounds)
The polishing composition liquid of the present invention can contain a quaternary alkyl ammonium compound. Examples of the quaternary alkylammonium include tetramethylammonium hydroxide, tetramethylammonium nitrate, tetraethylammonium hydroxide, tetraethylammonium nitrate, and steatrimethylammonium nitrate, with trimethylammonium hydroxide being particularly preferred. The content of the quaternary alkyl ammonium compound is preferably 0.01% by mass or more and 20% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less, and particularly preferably 0.5% by mass. The content is 2% by mass or less.

(acid)
The polishing composition liquid of the present invention preferably further contains an acid. The acid here is a compound having a structure different from that of the oxidizing agent for oxidizing the metal, and does not include an acid that functions as the above-mentioned oxidizing agent. The acid here has an action of promoting oxidation, adjusting pH, and buffering agent.
Examples of the acid include inorganic acids and organic acids within the range.
Examples of the inorganic acid include sulfuric acid, nitric acid, boric acid, phosphoric acid, etc. Among the inorganic acids, nitric acid and sulfuric acid are preferable.

  Moreover, as an organic acid, a water-soluble thing is desirable and what was chosen from the following groups is more suitable. Formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid , N-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid lactic acid, adipic acid, malic acid, and salts thereof such as ammonium salt and alkali metal salt, sulfuric acid, nitric acid, ammonia, ammonium Examples thereof include salts or a mixture thereof. Of these, formic acid, acetic acid and glycolic acid are preferred.

  The polishing composition liquid of the present invention preferably contains a compound having at least one carboxyl group and at least one amino group in the molecule as an organic acid, and at least one of the amino groups of the compound is secondary. Or it is more preferable that it is a tertiary. As the compound, α-amino acids such as glycine, alanine, valine and glutamic acid, β-amino acids such as β-alanine, iminodiacetic acid, hydroxyethyliminodiacetic acid, hydroxyethylglycine, dihydroxyethylglycine, glycylglycine, N-methylglycine etc. are mentioned. It is more preferable to contain two or more compounds having at least one carboxyl group and at least one amino group in the molecule, and a compound having only one carboxyl group in the molecule and two or more carboxyl groups in the molecule. It is particularly preferable to use in combination with a compound having the same. The amount of the compound having at least one carboxyl group and at least one amino group in the molecule is preferably 0.1% by mass or more and 5% by mass or less, and 0.5% by mass or more and 2% by mass or less. More preferably.

  The polishing composition liquid of the present invention can contain a compound having at least one amino group and at least one sulfo group in the molecule. Examples of the compound include aminomethanesulfonic acid and taurine. When added, taurine is preferred. The amount of the compound having at least one amino group and at least one sulfo group in the molecule is preferably from 0.1% by mass to 10% by mass, and more preferably from 1% by mass to 5% by mass.

(Additive)
Moreover, it is preferable to use the following additives for the polishing liquid of the present invention.
ammonia;
Alkylamines such as dimethylamine, trimethylamine, triethylamine, propylenediamine, and amines such as ethylenediaminetetraacetic acid (EDTA), sodium diethyldithiocarbamate and chitosan;
Dithizone, cuproin (2,2′-biquinoline), neocuproin (2,9-dimethyl-1,10-phenanthroline), bathocuproine (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and cupelazone ( Imines such as biscyclohexanone oxalyl hydrazone);
Benzimidazole-2-thiol, 2- [2- (benzothiazolyl)] thiopropionic acid, 2- [2- (benzothiazolyl)] thiobutyric acid, 2-mercaptobenzothiazole, 1,2,3-triazole, 1,2, 4-triazole, 3-amino-1H-1,2,4-triazole, benzotriazole, 1-hydroxybenzotriazole, 1-dihydroxypropylbenzotriazole, 2,3-dicarboxypropylbenzotriazole, 4-hydroxybenzotriazole, 4-carboxyl-1H-benzotriazole, 4-methoxycarbonyl-1H-benzotriazole, 4-butoxycarbonyl-1H-benzotriazole, 4-octyloxycarbonyl-1H-benzotriazole, 5-hexylbenzotriazol N- (1,2,3-benzotriazolyl-1-methyl) -N- (1,2,4-triazolyl-1-methyl) -2-ethylhexylamine, tolyltriazole, naphthotriazole, bis [( Azoles such as 1-benzotriazolyl) methyl] phosphonic acid;
Mercaptans such as nonyl mercaptan, dodecyl mercaptan, triazine thiol, triazine dithiol, triazine trithiol,
Other examples include tetrazole and quinaldic acid.
Among these, chitosan, ethylenediaminetetraacetic acid, L-tryptophan, cuperazone, triazinedithiol, benzotriazole, 4-hydroxybenzotriazole, 4-carboxyl-1H-benzotriazole butyl ester, tolyltriazole, and naphthotriazole have high CMP rates and low This is preferable for achieving both etching rates.

  The additive amount of these additives is preferably 0.0001 mol to 0.5 mol, more preferably 0.001 mol to 0.2 mol, and more preferably 0.005 mol to 0.2 mol in 1 L of a polishing liquid used for polishing. The amount is particularly preferably 0.1 mol. That is, the addition amount of the additive is preferably 0.0001 mol or more from the viewpoint of suppressing etching, and preferably 0.5 mol or less from the viewpoint of preventing a decrease in CMP rate.

(Alkaline agent and buffer)
The polishing composition liquid of the present invention can contain an alkali agent for adjusting the pH and, if necessary, a buffering agent from the viewpoint of suppressing pH fluctuation.

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

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

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

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

The polishing composition liquid of the present invention preferably has a pH of 2 to 9.5, and more preferably 2 to 7.
By setting the pH of the polishing composition liquid to 2 to 9.5, the dispersion stability and the function of colloidal silica particles into which aluminum atoms are introduced are easily exhibited.
The pH can be adjusted by using a known pH adjusting agent, such as the aforementioned acids (for example, sulfuric acid, nitric acid, boric acid, phosphoric acid, etc.) and alkali agents (for example, ammonia, amine compounds, etc.). Can be used.

<Chemical mechanical polishing method>
The chemical mechanical polishing method of the present invention (hereinafter also referred to as “CMP method” or “polishing method”) The polishing composition liquid of the present invention is brought into contact with the surface to be polished, and the surface to be polished and the polishing surface are moved relative to each other. And a polishing step (hereinafter also referred to as “polishing step”).
The chemical mechanical polishing method of the present invention comprises (a) colloidal silica particles in which at least some of the silicon atoms on the surface are covered with aluminum atoms, and (b) one or more types of surfaces that are positively charged. By using the polishing composition liquid of the present invention containing particles that are present, the polishing rate, corrosion, and in-plane uniformity are excellent in CMP.

(Wiring metal raw materials)
In the present invention, the object to be polished is, for example, a metal wiring in a semiconductor such as LSI, preferably a wiring made of copper metal and / or a copper alloy, particularly a wiring made of a copper alloy. Furthermore, the copper alloy containing silver is preferable among copper alloys. The silver content contained in the copper alloy is preferably 40% by mass or less, particularly 10% by mass or less, more preferably 1% by mass or less, and most preferably in the range of 0.00001 to 0.1% by mass. Exhibits excellent effects. As described above, the polishing composition liquid of the present invention is a polishing liquid that can be suitably used for polishing metal wirings in semiconductors such as LSI. Needless to say, the silicon substrate, silicon oxide, silicon nitride, resin, or the like may be partially polished due to the above effects.

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

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

(Polishing conditions, etc.)
The CMP method using the polishing composition liquid of the present invention will be further described.
In the polishing step using the polishing composition liquid of the present invention, it is preferable to continuously supply the polishing composition liquid to the polishing pad with a pump or the like during polishing. Although there is no restriction | limiting in this supply amount, it is preferable that the surface of a polishing pad is always covered with polishing liquid. After the polishing, the semiconductor substrate is preferably washed in running water and then dried after removing water droplets adhering to the semiconductor substrate using a spin dryer or the like.
In the polishing method using the polishing composition liquid of the present invention, the aqueous solution to be diluted is the same as the aqueous solution described below.
Aqueous solution is water containing at least one of metal oxidizer, metal oxide solubilizer, protective film forming agent, and surfactant in advance, and the component of the polishing composition liquid diluted with the component contained in the aqueous solution The total of the components is a component for polishing using the polishing composition liquid. When diluted with an aqueous solution and used, components that are difficult to dissolve can be blended in the form of an aqueous solution, and the polishing composition liquid can be further concentrated.

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

  The supply rate of the polishing composition liquid is preferably 10 to 1,000 ml / min, and more preferably 50 to 500 ml / min.

  Further, as a method for diluting by adding water or an aqueous solution to the concentrated polishing composition liquid, for example, a pipe for supplying the polishing composition liquid and a pipe for supplying water or an aqueous solution are provided independently, and each is separated from each other. A method in which a fixed amount of liquid is supplied to the polishing pad and mixed by relative movement between the polishing pad and the surface to be polished can be used. As another method for diluting the concentrated polishing composition liquid, a predetermined amount of the concentrated polishing composition liquid and water or an aqueous solution are mixed in one container, and then mixed with the polishing pad. There is a method of supplying a composition liquid.

In another polishing method using the polishing composition liquid of the present invention, the constituents to be contained in the polishing composition liquid are divided into at least two groups of constituent ingredients, and when they are used, they are diluted by adding water or an aqueous solution. Then, it is supplied to the polishing pad on the polishing surface plate and brought into contact with the surface to be polished, and the surface to be polished and the polishing pad are moved relative to each other for polishing. For example, a metal oxidizing agent is one component (A), an acid, an additive, a surfactant, and water are one component (B), and when they are used, the component (A ) And component (B) are diluted and used.
In addition, the additive component having low solubility is divided into two components (A) and (B), and the oxidizing agent, additive and surfactant are one component (A), and the acid, additive and surfactant are used. And water is used as one component (B), and when they are used, water or an aqueous solution is added to dilute the component (A) and the component (B). In this example, three pipes for supplying the component (A), the component (B), and water or an aqueous solution are required, and dilution mixing is combined into one pipe that supplies the three pipes to the polishing pad. Then, a method of mixing in the pipe, or a method of connecting two pipes and then connecting another pipe is used.

  For example, it 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 pipe of water or an aqueous solution is further combined. As another mixing method, for example, as described above, three pipes are directly guided to the polishing pad and mixed by relative movement of the polishing pad and the surface to be polished, and three components are mixed in one container. And a method for supplying a diluted polishing composition liquid to the polishing pad. In the above polishing method, one component containing a metal oxidant is made 40 ° C. or lower, the other components are heated in the range of room temperature to 100 ° C., and one component and another component or water Or when adding and diluting aqueous solution, it can also be made 40 degrees C or less after mixing. Since the solubility increases when the temperature is high, this is a preferable method for increasing the solubility of the raw material having low solubility in the polishing composition liquid.

  Since the raw material in which other components not containing a metal oxidant are heated and dissolved in the range of room temperature to 100 ° C. is precipitated in the solution when the temperature decreases, when using the component whose temperature has decreased, It is necessary to dissolve the preliminarily heated precipitate. For this, a means for feeding a component liquid that has been heated and dissolved, and a means for stirring a liquid containing a precipitate, feeding the liquid, and heating and dissolving the pipe can be employed. If the temperature of one component containing a metal oxidant is increased to 40 ° C. or higher, the metal oxidant may be decomposed. Therefore, the heated component and the heated component When it is mixed with one component containing a metal oxidant for cooling, the temperature is made 40 ° C. or lower.

  In the present invention, the components of the polishing composition liquid may be divided into two or more parts and supplied to the polishing surface. In this case, it is preferable to divide and supply the component containing an oxide and the component containing an acid. Further, the polishing composition liquid may be a concentrated liquid and supplied to the polishing surface separately from the dilution water.

(Barrier metal)
In the present invention, when a wiring made of copper metal and / or a copper alloy is used, it is preferable to provide a barrier layer for preventing copper diffusion between the wiring and the interlayer insulating film. The material used for the barrier layer is preferably a material selected from TaN, TaSiN, Ta, TiN, Ti, Nb, W, WN, Co, Zr, ZrN, Ru, and CuTa alloy, TiN, TiW, Ta, TaN, W, WN, and Ru are more preferable, and Ta, TaN, and Ru are particularly preferable.
As the interlayer insulating film, a thin film of an insulating material having a low dielectric constant is preferable, and a preferable insulating material is a material having a relative dielectric constant of 3.0 or less, more preferably a material having a dielectric constant of 2.8 or less. . Specific examples of preferable low dielectric constant materials include BlackDiamond (Applied Materials), FLARE (Honeywell Electronic Materials), SILK (Dow Chemical), CORAL (Novellus System), LKD (JSR) And HSG (manufactured by Hitachi Chemical Co., Ltd.).

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

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

[Preparation of specific colloidal silica (A-1)]
The pH is adjusted to 9.0 by adding ammonia water to 1000 g of a 20% by mass aqueous dispersion of a commercially available colloidal silica slurry (product name: Quattron PL-2L, manufacturer: Fuso Chemical Industries) having an average primary particle size of 17 nm. Thereafter, 15.9 g of an aqueous sodium aluminate solution having an Al ₂ O ₃ concentration of 3.6% by mass and a Na ₂ O / Al ₂ O ₃ molar ratio of 1.5 was slowly added within a few minutes while stirring at room temperature. Stir for 5 hours. The obtained sol was placed in a SUS autoclave apparatus, heated at 130 ° C. for 4 hours, and then filled with a hydrogen-type strongly acidic cation exchange resin (Amberlite IR-120B), and a hydroxyl-type strongly basic anion exchange resin. A column packed with (Amberlite IRA-410) was passed through the column at a space velocity of 1 h ⁻¹ at room temperature, and the initial distillation was cut.
The obtained specific colloidal silica (A-1) did not show thickening or gelation after preparation.

[Preparation of specific colloidal silica (A-2)]
The pH was adjusted to 9.0 by adding ammonia water to 1000 g of a 23% by mass aqueous dispersion of a commercially available colloidal silica slurry having an average primary particle size of 72 nm (product name: Quatron PL-7, manufacturer: Fuso Chemical Industries). Thereafter, 15.9 g of an aqueous sodium aluminate solution having an Al ₂ O ₃ concentration of 3.6% by mass and a Na ₂ O / Al ₂ O ₃ molar ratio of 1.5 was slowly added within a few minutes while stirring at room temperature. Stir for 5 hours. The obtained sol was placed in a SUS autoclave apparatus, heated at 130 ° C. for 4 hours, and then filled with a hydrogen-type strongly acidic cation exchange resin (Amberlite IR-120B), and a hydroxyl-type strongly basic anion exchange resin. A column packed with (Amberlite IRA-410) was passed through the column at a space velocity of 1 h ⁻¹ at room temperature, and the initial distillation was cut.
The obtained specific colloidal silica (A-2) did not show thickening or gelation after preparation.

[Preparation of aminosilane-coupled colloidal silica (B-1)]
Commercially available aminosilane coupling adjusted to pH 9.5 with respect to 1000 g of 10% by mass aqueous dispersion of commercially available colloidal silica slurry (product name: Quattron PL-7, manufacturer: Fuso Chemical Co., Ltd.) having an average primary particle size of 72 nm. 100 g of a 6% aqueous solution of the agent (manufactured by Shin-Etsu Chemical Co., Ltd., KBM903) was mixed. After stirring the mixed aqueous dispersion until homogeneous, the dispersion was lowered to pH 3 with nitric acid while stirring continued. After stirring for a while, the solvent replacement operation of ultrafiltration was repeated to obtain colloidal silica slurry (10 mass%) (B-1) modified with aminosilane coupling. The resulting aminosilane-modified colloidal silica (B-1) did not show thickening or gelation after preparation.

[Preparation of aminosilane-coupled colloidal silica (B-2)]
Aminosilane was used in the same manner as colloidal silica (B-1) except that a commercially available colloidal silica slurry (product name: Quatron PL-2L, manufacturer: Fuso Chemical Industries) having an average primary particle size of 17 nm was used. A coupling-modified colloidal silica slurry (B-2) was obtained. The resulting aminosilane-modified colloidal silica (B-2) did not show thickening or gelation after preparation.

  In this example, aminosilane coupling agent was used as a preparation for (b) particles having a positively charged surface, but ammonia or ammonium salts may be used instead. As the ammonium salt, ammonium nitrate is desirable.

  The average primary particle diameter shown in the present invention is a particle diameter when converted from a specific surface area value by the BET method to a true spherical particle model, and the specific surface area value is easily measured by a commercially available measuring apparatus (Shimadzu Corporation, Gemini V2380). Can be measured.

  The obtained (a) specific colloidal silica (A-1), (A-2) and (b) aminosilane-coupled colloidal silica (B-1), (B-2), general before the above operation When the zeta potential of the colloidal silica was measured using a commercially available zeta potential measuring device (manufactured by Otsuka Electronics Co., Ltd., ELS-Z1), the zeta potential shown in Table 1 was shown with respect to the pH shown in Table 1.

  From Table 1, specific colloidal silica (A-1) and (A-2) show that an aluminum atom is introduced via an oxygen atom with respect to at least a part of silicon atoms on the surface of the colloidal silica particle. It is thought that there is. Furthermore, the colloidal silicas (B-1) and (B-2) treated with aminosilane coupling have been confirmed to have positive zeta potentials over a wide range of pH, with amino groups introduced on their surfaces. It was done.

<Examples 1-7, Comparative Examples 1 and 2>
(Preparation of polishing composition liquid)
As the polishing composition liquids of Examples 1 to 7, the specific colloidal silica (A-1) or (A-2) as aluminum atom-introduced particles (abrasive grains (a)), and the reverse of the aluminum atom-introduced particles A polishing composition liquid containing colloidal silica (B-1) or (B-2) subjected to aminosilane coupling treatment as abrasive grains (abrasive grains (b)) exhibiting a ζ potential was prepared with the composition shown in Table 2. Moreover, the polishing composition liquid of the composition of Table 2 was prepared as the polishing composition liquid of Comparative Examples 1 and 2.
Further, Table 3 shows the sign (+ or −) of ζ potential of each of the prepared polishing composition liquids.

  In the preparation of the polishing composition liquid described above, the pH was adjusted with ammonia and nitric acid, and 1% hydrogen peroxide was added to each example and comparative example immediately before the polishing experiment. About the polishing composition liquid in which aggregation was observed over time, the water-soluble polymer and the surfactant were added to ensure dispersibility.

  Using the polishing composition liquids prepared in Examples 1 to 7 and Comparative Examples 1 and 2, polishing was performed by the following polishing method, and the polishing performance (polishing rate and amount of dishing) was evaluated. The evaluation results are shown in Table 4.

(Polishing method: Polishing using 8-inch wafer)
The apparatus “LGP-612” manufactured by Lapmaster Co. was used as a polishing apparatus, and the copper film provided on each wafer was polished under the following conditions while supplying a polishing composition liquid (slurry).
Object to be polished (substrate): Silicon wafer with 8 inch copper film Table rotation speed: 50 rpm
Head rotation speed: 50 rpm
Polishing pressure: 2.0 psi
Polishing pad: Product number IC-1400 manufactured by Rohm & Haas Co., Ltd.
Slurry supply rate: 200 ml / min

<Evaluation>
1. Polishing rate The polishing rate was calculated from the electrical resistance before and after polishing and converted into the film thickness by the following formula.
Polishing rate (nm / min) = (thickness of copper film before polishing−thickness of copper film after polishing) / polishing time

2. The dishing evaluation substrate is formed by patterning a silicon oxide film 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 500 nm, and a sputtering method. After forming a Ta film with a thickness of 20 nm by a sputtering method, and subsequently forming a copper seed layer with a thickness of 50 nm by a sputtering method, a wafer having a copper film with a total thickness of 1000 nm formed by a plating method was used.
The substrate is polished under the above-mentioned polishing conditions while supplying slurry onto the polishing cloth of the polishing surface plate of the polishing apparatus. The point where the wiring metal is cleared is taken as the just point, and overpolishing with 30% overpolish from the just point. Time was measured, and the step in 100 μm / 100 μm Line / Space was measured using a stylus type step gauge to obtain dishing.

  As shown in Table 4, by using the polishing composition liquid of the present invention of Examples 1-7, the Cu clearability is good while maintaining a high polishing rate (variation of Cu remaining in the wafer surface). Is small (= polishing time can be shortened), and CMP performance with excellent dishing performance can be obtained (overpolishing time can be shortened, resulting in small dishing (= overpolishing time) If you have a long time, dishing will worsen).

Claims (7)

A polishing composition liquid comprising the following (a) to (c):
(A) Colloidal silica particles in which at least some of the silicon atoms on the surface are covered with aluminum atoms (b) One or more types of particles whose surface is positively charged (c) Water   2. The polishing composition liquid according to claim 1, wherein the (b) one or more kinds of particles having a positively charged surface include colloidal silica. 3.   The (b) one or more kinds of particles having a positively charged surface include colloidal silica in which at least a part of the surface is surface-modified with an aminosilane coupling agent. 2. The polishing composition liquid according to 2.   (B) One or more kinds of particles having a positively charged surface are polystyrene and styrene copolymer, methacrylic resin or acrylic resin and copolymers thereof, polyvinyl chloride, polyacetal, saturated polyester, polyamide The polishing composition liquid according to claim 1, comprising at least one selected from the group consisting of polyimide, polycarbonate, phenoxy resin, polyethylene, polypropylene, polyolefin, and polyvinylbenzene.   (A) The average primary particle diameter of colloidal silica particles in which at least a part of silicon atoms on the surface is covered with aluminum atoms is in the range of 20 nm to 400 nm, and (b) one or more types of surfaces have a positive charge. The polishing composition liquid according to any one of claims 1 to 4, wherein the average primary particle diameter of the charged particles is in the range of 3 nm to 90 nm.   (A) The average primary particle diameter of the colloidal silica particles in which at least a part of silicon atoms on the surface is covered with aluminum atoms is in the range of 3 nm to 90 nm, and (b) one or more types of surfaces have a positive charge. The polishing composition liquid according to any one of claims 1 to 4, wherein the average primary particle diameter of the particles charged in a range of 20 nm to 400 nm.   The polishing composition liquid according to any one of claims 1 to 6, wherein the pH is adjusted to a range of 2 to 9.5.