JP5383164B2 - Polishing liquid - Google Patents

Description

  The present invention relates to a polishing liquid used in a manufacturing process of a semiconductor device, and in particular, a specific composition suitably used for polishing a barrier layer mainly made of a barrier metal material in planarization in a wiring process of a semiconductor device. It relates to a polishing liquid containing.

  In the development of a semiconductor device represented by a semiconductor integrated circuit (hereinafter referred to as LSI), in recent years, in order to reduce the size and increase the speed, there has been a demand for higher density and higher integration by miniaturizing and stacking wiring. For this purpose, various techniques such as chemical mechanical polishing (hereinafter referred to as CMP) have been used. This CMP is an indispensable technique for surface flattening of processed films such as interlayer insulation films, plug formation, formation of embedded metal wiring, etc., and smoothing of the substrate and removal of excess metal thin film during wiring formation In addition, an excess barrier layer on the insulating film is removed.

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.
When manufacturing semiconductor devices such as LSI, fine wiring is formed in multiple layers, and when forming metal wiring such as Cu in each layer, diffusion of wiring material to the interlayer insulating film In order to prevent this and to improve the adhesion of the wiring material, a barrier metal such as Ta, TaN, Ti, or TiN is formed in advance.

In order to form each wiring layer, first, CMP of a metal film (hereinafter referred to as metal film CMP) for removing excess wiring material stacked by plating or the like is performed in one or more stages. Next, CMP (hereinafter referred to as barrier metal CMP) for removing the barrier metal material (barrier metal) exposed on the surface by this is generally performed. However, there is a problem that the metal film CMP causes so-called dishing in which the wiring portion is excessively polished and further causes erosion.
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 or the interlayer insulating film is relatively small compared to the metal wiring material, dishing such as polishing of the wiring portion is caused and erosion as a result is generated. Therefore, 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.

The metal polishing solution used for CMP generally contains abrasive grains (for example, alumina, silica, cerium oxide, zirconia) and an oxidizing agent (for example, hydrogen peroxide, persulfuric acid, hypochlorous acid, nitric 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, polishing scratches, a phenomenon in which the entire polished surface is polished more than necessary (thinning), and a phenomenon in which the polished metal surface bends on the dish. (Dishing), an insulator between metal wirings is polished more than necessary, and a plurality of wiring metal surfaces may bend on the plate (erosion).
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, a CMP polishing agent and a polishing method (for example, refer to Patent Document 1) aiming at high-speed polishing with almost no polishing scratches generated, a polishing composition and a polishing method with improved cleaning performance in CMP (for example, , And Patent Document 2) and a polishing composition (see, for example, Patent Document 3) that prevents aggregation of abrasive grains have been proposed.
However, even with the above-described polishing liquid, there has not yet been obtained a technique that can realize a high polishing rate for various films to be polished and can control each polishing rate independently when polishing the barrier layer. There is no current situation.
JP 2003-17446 A JP 2003-142435 A JP 2000-84832 A

Recently, an insulating film (Low-k film) having a lower dielectric constant and lower strength has come to be used. This is because the state-of-the-art device has a short distance between the wirings, and therefore, when an insulating film having a high dielectric constant is used, an electrical failure occurs between the wirings. Since such a Low-k film has a very low strength, there has been a problem that it is excessively shaved during processing during CMP.
For such problems, the polishing rate for the film to be polished when polishing the barrier layer is maintained at a high polishing rate, and the polishing rate for the low-k low-k film is sufficiently suppressed. The technology that can be obtained has not been obtained so far.
Accordingly, an object of the present invention is a polishing liquid using solid abrasive grains used in barrier CMP for polishing a barrier layer made of a barrier metal material, and increases the polishing rate for a film to be polished when polishing the barrier layer. An object of the present invention is to provide an abrasive capable of maintaining the polishing rate and sufficiently suppressing the polishing rate for a low-k low-k film.

As a result of intensive studies, the present inventor has found that the above problem can be solved by using the following polishing liquid, and has achieved the object.
The polishing liquid and polishing method of the present invention are as follows.
(1) abrasive particles, the polishing composition comprising at least one surfactant which have a two or more tertiary amino groups and one lipophilic portion represented by the following general formula (F), and water :
Formula (F)

(In the formula, R represents an alkyl group having 6 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, or an aralkyl group. X, y, and z are each an integer of 1 or more, and n is an integer of 1 or more. Represent) Preferably, x, y, and z are each an integer of 1 to 10, and n is an integer of 1 to 20.
(2) Polishing composition as described in (1) whose said abrasive particle is 0.05-30 mass% or less with respect to the mass of the polishing liquid used for grinding | polishing.
(3) The polishing composition according to (1) or (2), wherein the abrasive particles contain at least one selected from fumed silica, colloidal silica, ceria, and alumina.
(4) In any one of (1) to (3), further comprising a compound represented by the following general formula (1) and / or a compound represented by the following general formula (2) The polishing composition as described.

(In General Formula (1), R ^{1 to} R ⁴ each independently represents an alkyl group, alkenyl group, cycloalkyl group, aryl group, or aralkyl group having 1 to 20 carbon atoms. X ⁻ represents a monovalent group. In addition, any two of R ^{1 to} R ⁴ may be bonded to each other to form a cyclic structure.
In General Formula (2), R ^{5 to} R ¹⁰ each independently represent an alkyl group having 1 to 20 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, or an aralkyl group. M represents an alkylene group having 1 to 10 carbon atoms, an alkenylene group, a cycloalkylene group, an arylene group, or a group obtained by combining two or more thereof. X ⁻ represents a monovalent anion, and Y ²⁻ represents a divalent anion. Note that any two of R ^{5 to} R ¹⁰ may be bonded to each other to form a cyclic structure. )
(5) Polishing composition in any one of (2)-(4) whose quantity of the compound represented by the said general formula (F) is the range of 0.000001 mass%-20 mass%.
(6) A polishing liquid containing the polishing composition according to any one of the above (1) to (5) is brought into contact with the surface to be polished, and the surface to be polished and the polishing means are moved relative to each other for polishing. A method for chemically mechanically polishing a surface to be polished.
(7) The polishing platen on which the polishing pad is placed is rotated, the polishing liquid containing the polishing composition according to any one of (1) to (5) is supplied to the polishing pad, and the object to be polished is covered. A chemical mechanical polishing method comprising polishing an object to be polished by moving a polishing surface in contact with the polishing pad and making a relative movement.
(8) A semiconductor device having at least one selected from the group consisting of TiN, TiW, Ta, TaN, W and WN polished by the polishing method according to (6) or (7) as a barrier layer.

  The polishing liquid containing the polishing composition of the present invention can maintain the polishing rate for the film to be polished at a high polishing rate, and can sufficiently suppress the polishing rate for the low-k low-k film.

Hereinafter, specific embodiments of the present invention will be described.
The polishing liquid of the present invention is a polishing liquid used for chemical mechanical polishing of a barrier layer and an interlayer insulating film of a semiconductor integrated circuit, and contains a polishing particle, at least one surfactant and water. A polishing composition characterized in that at least one of the surfactants is a compound containing two or more tertiary amino groups and one lipophilic part. It is. Furthermore, an arbitrary component may be included as necessary. Moreover, each component which the polishing liquid of this invention contains may be used individually by 1 type, and may be used together 2 or more types.

In the present invention, the “polishing liquid” means not only a polishing liquid used for polishing (that is, a polishing liquid diluted as necessary) but also a concentrated liquid of the 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 polishing liquid of this invention is demonstrated in detail.

1. Abrasive particles (abrasive grains)
The polishing liquid of the present invention contains abrasive grains. As the abrasive grains, those commonly used in the industry such as alumina, ceria, titanium, manganese, zirconia, and diamond can be used in addition to silica. Among these, silica, alumina, and ceria are preferably used, and silica can be preferably used in terms of reducing scratches. Among silicas, colloidal silica and fumed silica can be used depending on the purpose, but colloidal silica can be more preferably used from the viewpoint of suppressing scratches.
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, but it can be appropriately selected depending on the purpose.
The particle size of the colloidal silica is appropriately selected depending on the purpose of use of the abrasive grains, but is generally about 5 to 200 nm, but is preferably in the range of 10 to 180 nm from the viewpoint of reducing scratches. . The primary average particle size of colloidal silica is preferably 20 to 50 nm. This is because the high polishing rate and the low scratch are compatible.

  The content (concentration) of the abrasive grains in the polishing liquid of the present invention is preferably 0.05% by mass or more and 40% by mass or less, and more preferably 0% with respect to the mass of the polishing liquid used for polishing. .1% to 35% by mass, particularly preferably 0.3% to 30% by mass. That is, the content of abrasive grains is preferably 0.1% by mass or more from the viewpoint of polishing the barrier layer at a sufficient polishing rate, and preferably 30% by mass or less from the viewpoint of storage stability and suppression of scratches.

In the polishing liquid of the present invention, different types of abrasive grains can be used in combination as long as the effects of the present invention are not impaired. In that case, the content of colloidal silica in all abrasive grains is preferably 50% by mass. It is above, and it is especially preferable that it is 80 mass% or more preferably. All of the contained abrasive grains may be colloidal silica.
Examples of abrasive grains that can be used in combination with the polishing liquid of the present invention include colloidal silica, fumed silica, ceria, alumina, and titania. The size of these combined abrasive grains is preferably the same as that of colloidal silica or 0.5 to 2 times or less.

2. Surfactant In the present invention, the polishing composition contains at least one surfactant, and at least one of the surfactants contains two or more tertiary amino groups and one lipophilic part. It is characterized by being. By containing the surfactant, the polishing rate for the low-k film type can be freely controlled. The lipophilic group includes an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an aralkyl group, a combination thereof, and the like, and refers to a group that does not contain a hydrophilic functional group.

As an example of a surfactant having two or more tertiary amino groups and one lipophilic part, a surfactant represented by the following general formula (F) is preferable.
Formula (F):
(In the formula, R represents an alkyl group having 6 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group or an aralkyl group, and x, y and z are each an integer of 1 or more, and n is an integer of 1 or more. Represent).
One lipophilic part corresponds to R in the case of the surfactant represented by the general formula (F).

Specific examples of the alkyl group having 6 to 30 carbon atoms include a decyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, an octadecyl group, an icosyl group, and a triacontyl group. Among them, a dodecyl group, a tetradecyl group, and the like can be given. Group, hexadecyl group and octadecyl group are preferred.
The alkenyl group preferably has 6 to 30 carbon atoms, and specific examples include a decel group, a dodecel group, a tetradecel group, a hexadecel group, an octadecel group, an icocel group, a triacontel group, and the like. Among these, a dodecel group, a tetradecel group, a hexadecel group, and an octadecel group are preferable.

Specific examples of the cycloalkyl group include a cyclohexyl group and an alkyl-substituted cyclohexyl group.
Specific examples of the aryl group include a phenyl group and a naphthyl group, and among them, a phenyl group is preferable.
As said polyoxyethylene chain (EO), the value of x + y + z is preferably 3-50, more preferably 3-30, still more preferably 3-20.
Moreover, 1-20 are preferable, as for the value of n, 2-10 are more preferable, and 3-6 are more preferable.

  Each of the above groups may further have a substituent. Examples of the substituent that can be introduced include a hydroxy group, an amino group, a carboxyl group, a phosphate group, an imino group, a thiol group, a sulfo group, and a nitro group. Groups and the like.

  Some of these surfactants are commercially available. For example, it is an ethylene oxide adduct of monoalkyldiamine, represented by the Ethoduomeen series manufactured by Lion Akzo Co., which has two amine groups and one lipophilic group in the molecule. , Esoduomine T / 11, Esoduomine T / 13, Esoduomine T / 25, and the like.

  The addition amount of the surfactant can be preferably used in the range of 0.000001% by mass to 20% by mass, preferably 0.000002% by mass to 10% by mass, and more preferably 0.000005% by mass to 5%. It is preferably used in the range of mass%, but the optimum addition amount varies depending on the molecular weight of the surfactant, the number of alkyl groups in the lipophilic part, and the number of amine groups, and is generally limited to the above addition amount range. It goes without saying that it is not.

  Furthermore, it is also possible to use the surfactant described below in combination with the above surfactant. These surfactants improve the polishing rate of other film types by adjusting the type and amount of the surfactant without impairing the polishing rate control action of the low-k film types of the above-mentioned surfactants. In addition, the polishing rate of an insulating layer such as a TEOS film can be controlled. In addition, there are some which can be used as a polishing rate adjustment auxiliary agent for the low-k film type in combination. As the surfactant used in combination, an anionic surfactant or a cationic surfactant is preferably used.

  The surfactant used in the present invention may be any of a cationic surfactant, a nonionic surfactant, and an anionic surfactant, but an anionic surfactant is preferable, and an acid type is preferable. Examples of the salt include ammonium salt, potassium salt, sodium salt and the like, and sodium salt, ammonium salt and potassium salt are particularly preferable, and those selected from the following groups are preferable.

  Examples of the anionic surfactant include carboxylic acid or a salt thereof, sulfonic acid or a salt thereof, sulfate ester salt, and phosphate ester salt. As the carboxylic acid or salt thereof, soap, N-acylamino acid or a salt thereof, polyoxy Ethylene or polyoxypropylene alkyl ether carboxylic acid or salt thereof, acylated peptide; as sulfonic acid or salt thereof, alkylsulfonic acid or salt thereof, alkylbenzene and alkylnaphthalenesulfonic acid or salt thereof, naphthalenesulfonic acid or salt thereof, sulfosuccinate Acid or salt thereof, α-olefin sulfonic acid or salt thereof, N-acyl sulfonic acid or salt thereof; as sulfate ester salt, sulfated oil, alkyl sulfuric acid or salt thereof, alkyl ether sulfuric acid or salt thereof, polyoxyethylene or poly Oxypropylene alkyl ant Ether sulfuric acid or a salt thereof, alkylamide sulfuric acid or a salt thereof; examples of phosphoric acid ester salts include alkyl phosphoric acid or a salt thereof, polyoxyethylene or polyoxypropylene alkylallyl ether phosphoric acid or a salt thereof, Acids or sulfonates are preferably used.

  Examples of the cationic surfactant include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium chloride salts, benzethonium chloride, pyridinium salts, imidazolinium salts; amphoteric surfactants such as carboxybetaine type and sulfobetaine. Mention may be made of types, aminocarboxylates, imidazolinium betaines, lecithins, alkylamine oxides.

  Examples of the nonionic surfactant include ether type, ether ester type, ester type, and nitrogen-containing type. As the ether type, polyoxyethylene alkyl and alkylphenyl ether, alkylallyl formaldehyde condensed polyoxyethylene ether, polyoxyethylene ether Examples include ethylene polyoxypropylene block polymer, polyoxyethylene polyoxypropylene alkyl ether, and ether ester types such as glycerin ester polyoxyethylene ether, sorbitan ester polyoxyethylene ether, sorbitol ester polyoxyethylene ether, ester type As polyethylene glycol fatty acid ester, glycerin ester, polyglycerin ester, sorbitan ester, propylene glycol Ester, sucrose ester, a nitrogen-containing type, fatty acid alkanolamides, polyoxyethylene fatty acid amides, polyoxyethylene alkyl amide, and the like.

  In addition, examples of the surfactant that can be used in the present invention include amphoteric surfactants such as betaine type, amino acid type, imidazoline type, and amine oxide type, and fluorine-based surfactants. These surfactants may be used alone or in combination of two or more, or different types of surfactants may be used in combination.

The total content of these surfactants in the polishing liquid of the present invention is preferably 1 × 10 ⁻⁶ mass% to 5 mass%, more preferably 1 × 10 ^{−6 in} the polishing liquid used for polishing. It is 1 mass%-3 mass%, More preferably, it is 1 * 10 < ^-6 > mass%-2.5 mass%.

3. [Monoquaternary ammonium salt, diquaternary ammonium salt compound]
The polishing liquid of the present invention further contains at least one selected from the group consisting of a monoquaternary ammonium salt compound and a diquaternary ammonium salt compound (hereinafter, this may be simply referred to as “specific cation”). You may do it.
The monoquaternary ammonium salt compound is not particularly limited as long as it has a structure containing one quaternary nitrogen in the chemical structure. The diquaternary ammonium salt compound that can be contained in the polishing liquid of the present invention is not particularly limited as long as it has a structure containing two quaternary nitrogens in the chemical structure.
The specific cation is preferably a monoquaternary ammonium cation or a diquaternary ammonium cation from the viewpoint of achieving a sufficient polishing rate improvement.
As a monoquaternary ammonium salt compound, the compound represented by following General formula (1) is mentioned, for example. As a diquaternary ammonium salt compound, the compound represented by following General formula (2) is mentioned, for example.
Especially, it is preferable that it is any one or both of the compound represented by the following general formula (1) and the compound represented by General formula (2) from a viewpoint of achieving sufficient improvement of polishing rate.

(In General Formula (1), R ^{1 to} R ⁴ each independently represents an alkyl group, alkenyl group, cycloalkyl group, aryl group, or aralkyl group having 1 to 20 carbon atoms. X ⁻ represents a monovalent group. In addition, any two of R ^{1 to} R ⁴ may be bonded to each other to form a cyclic structure.
In General Formula (2), R ^{5 to} R ¹⁰ each independently represent an alkyl group having 1 to 20 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, or an aralkyl group. M represents an alkylene group having 1 to 10 carbon atoms, an alkenylene group, a cycloalkylene group, an arylene group, or a group obtained by combining two or more thereof. X ⁻ represents a monovalent anion, and Y ²⁻ represents a divalent anion. Note that any two of R ^{5 to} R ¹⁰ may be bonded to each other to form a cyclic structure. )

Specific examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. Group, ethyl group, propyl group and butyl group are preferred.
Moreover, as said alkenyl group, a C2-C10 thing is preferable, Specifically, an ethynyl group, a propyl group, etc. are mentioned, for example.

Specific examples of the cycloalkyl group include a cyclohexyl group and a cyclopentyl group, and among them, a cyclohexyl group is preferable.
Specific examples of the aryl group include a butynyl group, a pentynyl group, a hexynyl group, a phenyl group, and a naphthyl group. Among them, a phenyl group is preferable.
Specific examples of the aralkyl group include a benzyl group, and among them, a benzyl group is preferable.

  Each of the above groups may further have a substituent. Examples of the substituent that can be introduced include a hydroxy group, an amino group, a carboxyl group, a phosphate group, an imino group, a thiol group, a sulfo group, and a nitro group. Groups and the like.

M in the general formula (2) represents at least one selected from the group consisting of an alkylene group having 1 to 10 carbon atoms, an alkenylene group, a cycloalkylene group, an arylene group, and a group in which two or more of these groups are combined.
The linking group represented by M includes -S-, -S (= O) _2- , -O-, -C (= O)-in the chain in addition to the above organic linking group. May be included.

Specific examples of the alkylene group having 1 to 10 carbon atoms include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, and an octylene group. Group and pentylene group are preferred.
Specific examples of the alkenylene group include an ethynylene group and a propynylene group, among which a propynylene 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.

  Each of the above linking groups may further have a substituent. Examples of the substituent that can be introduced include a hydroxy group, an amino group, a carboxyl group, a phosphate group, an imino group, a thiol group, a sulfo group, and a nitro group. Groups and the like.

  Specific examples of diquaternary ammonium salt compounds (Exemplary Compounds A1 to A32) and monoquaternary ammonium salt compounds (Exemplary Compounds A33 to A44) that can be contained in the polishing liquid of the present invention are shown below. The present invention is not limited to these.

Incidentally, cycrohC ₆ H ₁₂ in A43 shows a cyclohexyl group.

Among these, from the viewpoint of dispersion stability in the slurry, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A18, A19, A23, A24, A29, A30, A31, A32, A33, A34, A35, A36, A37, A41, and A42 are preferable.
A specific cation can be used individually or in combination of 2 or more types, respectively.

  The specific cation that can be contained in the polishing liquid of the present invention is not particularly limited in its production, and can be synthesized, for example, by a substitution reaction in which ammonia or various amines serve as a nucleophile. Moreover, the purchase as a general sale reagent is also possible.

  The specific cation addition amount in the present invention is the polishing liquid used for polishing (that is, the diluted polishing liquid when diluted with water or an aqueous solution. The following “polishing liquid used for polishing” is also agreed) Is preferably from 0.001 g / L to 10 g / L, more preferably from 0.01 g / L to 3 g / L. That is, the amount of the specific cation added is preferably 0.001 g / L or more from the viewpoint of sufficiently improving the polishing rate, and preferably 10 g / L or less from the viewpoint of sufficient slurry stability.

4). Anticorrosive Agent The polishing liquid of the present invention may contain an anticorrosive agent (also referred to as a corrosion inhibitor) that adsorbs to the surface to be polished to form a film and controls corrosion of the metal surface. As the anticorrosive agent that can be used in the present invention, a compound that forms a passive film on the surface of the metal to be polished is selected, and specific examples include a heteroaromatic ring compound.

  Here, the “heteroaromatic ring compound” is a compound having a heterocycle containing one or more heteroatoms. A hetero atom means an atom other than a carbon atom and 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.

  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 heteroaromatic ring that is the mother nucleus is described.
The number of members of the heterocyclic ring of the heteroaromatic ring compound that can be used in the present invention is not particularly limited, and it 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. The number of rings in the case of having a condensed ring is preferably 2 to 4, more preferably 2 or 3.

Specific examples of these heteroaromatic rings include the following. However, it is not limited to these.
For example, 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 , Pyridine ring, pyrimidine 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, Lysine ring, acridine ring, 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, A benzothiazole ring, a benzothiadiazole ring, a benzofuroxan ring, a naphthimidazole ring, a benzotriazole ring, a tetraazaindene ring and the like are mentioned, and a triazole ring and a tetrazole ring are more preferred.

Next, substituents that the heteroaromatic 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 the heteroaromatic ring compound may have include the following. However, it is not limited to these.
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 even a polycyclic alkyl group such as a bicycloalkyl group is active. A methine group), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (regardless of the position of substitution), an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a heterocyclic oxycarbonyl group, a carbamoyl group ( Examples of the carbamoyl group having a substituent include an N-hydroxycarbamoyl group, an N-acylcarbamoyl group, an N-sulfonylcarbamoyl group, an N-carbamoylcarbamoyl group, a thiocarbamoyl group, and an N-sulfamoylcarbamoyl group), a carbazoyl group. , Carboxyl group or salt thereof, oxalyl group, oxy Moyl group, cyano group, carbonimidoyl group, formyl group, hydroxy group, alkoxy group (including groups containing repeating ethyleneoxy or propyleneoxy group units), 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, sulfonamido group, ureido group, thioureido group, N-hydroxyureido group, Imido group, (alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfur Nylureido 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 , A sulfo group or a salt thereof, a sulfamoyl group (the sulfamoyl group having a substituent is, for example, an N-acylsulfamoyl group or an N-sulfonylsulfamoyl group) or a salt thereof, a phosphino group, a phosphinyl group, a phosphinyloxy Group, phosphinylamino group, silyl group, etc. It is.

  Here, “active methine group” means a methine group substituted with two electron-attracting groups. “Electron withdrawing group” means, for example, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group, trifluoromethyl group, cyano group, nitro group, carvone An imidoyl group is 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 in the heteroaromatic ring compound include, for example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched or cyclic alkyl group, and bicycloalkyl). A group such as a polycyclic 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, Aryloxycarbonyl group, heterocyclic oxycarbonyl group, carbamoyl group, N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group, A carbazoyl group, an oxalyl group, an oxamoyl group, Ano group, carbonimidoyl group, formyl group, hydroxy group, alkoxy group (including groups containing repeating 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- Silureido group, N-acylsulfamoylamino group, hydroxyamino group, nitro group, quaternized heterocyclic group containing nitrogen atom (for example, pyridinio group, imidazolio group, quinolinio group, isoquinolinio group), isocyano group, imino group 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-acylsulfamoyl group, N-sulfonylsulfamoyl group or a salt thereof, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, silyl group and the like.

  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-described substituents may jointly form a ring (aromatic or non-aromatic hydrocarbon ring or heteroaromatic ring), which are further combined to form a polycyclic fused ring. Examples thereof include 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, a Lysine ring, phenanthroline ring, thianthrene ring, chromene ring, xanthene ring, phenoxathiin ring, phenothiazine ring, phenazine ring, also form mentioned are) it is.

Specific examples of the heteroaromatic ring compound include, but are not limited to, the following.
For example, 1,2,3,4-tetrazole, 5-amino-1,2,3,4-tetrazole, 5-methyl-1,2,3,4-tetrazole, 1H-tetrazol-5-acetic acid, 1H- Tetrazole-5-succinic acid, 1,2,3-triazole, 4-amino-1,2,3-triazole, 4,5-diamino-1,2,3-triazole, 4-carboxy-1H-1,2, , 3-triazole, 4,5-dicarboxy-1H-1,2,3-triazole, 1H-1,2,3-triazole-4-acetic acid, 4-carboxy-5-carboxymethyl-1H-1,2 , 3-triazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, 3-carboxy-1,2,4-triazole 3,5- Carboxy-1,2,4-triazole, 1,2,4-triazole-3-acetic acid, 1H benzotriazole, 1H-benzotriazole-5-carboxylic acid, 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, among others, 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) benzene It is more preferably selected from Zotoriazoru.
These anticorrosive agents can be used alone or in combination of two or more.

  The content of the heteroaromatic ring compound in the polishing liquid of the present invention is, as a total amount, 0.0001 in 1 L of a polishing liquid used for polishing (that is, a diluted polishing liquid when diluted with water or an aqueous solution). The range of -1.5 mol is preferable, More preferably, it is the range of 0.0005-1.0 mol, More preferably, it is the range of 0.0005-0.8 mol.

5. Acid etc. The polishing liquid of the present invention may contain an acid. As the acid, an inorganic acid or an organic acid can be used according to the purpose, and these acids can be used in combination. In the present invention, the following organic acids having a carboxyl group can be preferably used. 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, but the polishing rate for the film to be polished when polishing the barrier layer is maintained at a high polishing rate, and From the viewpoint of a polishing rate structure that can sufficiently suppress the polishing rate for a low-k low-k film, it is preferable to select a compound represented by the following general formula (4).
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.

R ⁷ —O—R ⁸ —COOH General formula (4)

In the general formula (4) represents R ⁷ and R ⁸ each independently a hydrocarbon group, preferably represents a hydrocarbon group having 1 to 10 carbon atoms.
R ⁷ is a monovalent hydrocarbon group, 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), an alkoxy group, an aryloxy group Groups and the like are preferred.
R ⁸ is a divalent hydrocarbon group, for example, an alkylene group having 1 to 10 carbon atoms (for example, a methylene group or a cycloalkylene group), an arylene group (for example, a phenylene group), an alkyleneoxy group, or the like. preferable.
The hydrocarbon group represented by R ⁷ and R ⁸ may further have a substituent. 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. Group, etc., and when it has 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 (4) 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, methoxyacetic acid and phenoxyacetic acid are preferable from the viewpoint of polishing the surface to be polished at high speed.

In the polishing liquid of the present invention, the addition amount of the compound having a carboxyl group (preferably the compound represented by the general formula (4)) is 0.01 mass relative to the mass of the polishing liquid used for polishing. % To 10% by mass, more preferably 0.1% to 5% by mass. 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.
6). Oxidizing agent The polishing liquid of the present invention can also contain a compound (oxidizing agent) 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, 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 iron (III) in addition to inorganic iron (III) salts such as iron nitrate (III), iron chloride (III), iron sulfate (III) and iron bromide (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 preferably 0.001 mol to 3 mol in 1 L of a polishing liquid used for polishing. Particularly preferred is 005 mol to 2 mol.

In addition to the above components, the following components can be added to the abrasive of the present invention as necessary.
7). Conditioning agent The polishing liquid of the present invention is not regulated in pH and can be used at a pH of 14 or less, preferably in the range of pH 2.0 to 11.0, and more preferably in the range of pH 2.0 to 5.0. It is preferable that it exists in. 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 2.0 mol in 1 L of the polishing liquid used for polishing. More preferably, it is 0.003 mol to 1 mol.

8). Chelating Agent The polishing liquid of the present invention preferably contains a chelating agent (that is, a hard water softening agent) as necessary in order to reduce adverse effects such as mixed polyvalent metal ions.
Chelating agents include general water softeners and related compounds that are calcium and magnesium precipitation inhibitors, such as nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, N, N, N-trimethylenephosphonic acid. , Ethylenediamine-N, N, N ′, N′-tetramethylenesulfonic acid, transcyclohexanediaminetetraacetic acid, 1,2-diaminopropanetetraacetic acid, glycol etherdiaminetetraacetic acid, ethylenediamine orthohydroxyphenylacetic acid, ethylenediamine disuccinic acid ( SS form), N- (2-carboxylateethyl) -L-aspartic acid, β-alanine diacetic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, N , N′-bis (2-hydroxyben Le) ethylenediamine -N, N'-diacetic acid, 1,2-dihydroxy-4,6-disulfonic acid.

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, 0.0001 mol to 0.1 mol in 1 L of a polishing liquid used for polishing. Add to be.

  The polishing liquid of the present invention is generally suitable for polishing a barrier layer made of a barrier metal material for preventing diffusion of copper, which exists between a wiring made of copper metal and / or a copper alloy and an interlayer insulating film.

[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 to be polished by the polishing liquid of the present invention, in addition to a commonly used interlayer insulating film such as TEOS, for example, a low dielectric constant material having a relative dielectric constant of about 3.5 to 2.0 (for example, Examples thereof include organic polymer-based, SiOC-based, SiOF-based, etc., and an interlayer insulating film including abbreviated as a Low-k film).
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.

[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 polishing liquid of the present invention is 1. 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 polishing liquid 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 50 to 800 ml / min in order to satisfy the uniformity of the polishing rate within the surface to be polished 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 oxidant is used as the component (A), an organic acid, an additive, a surfactant, and water are used as the component (B). A component (B) can be diluted and used. The abrasive particles may be placed in either or both.
Further, an additive having low solubility is divided into two constituent components (A) and (B). For example, an oxidizing agent, an additive, and a surfactant are used as the constituent component (A), and an organic acid, an additive, and a surface active agent are used. An agent and water are used as the component (B), and when they are used, water or an aqueous solution is added to dilute the component (A) and the component (B).

In the case of the above example, three pipes for supplying the component (A), the component (B), and water or an aqueous solution are required, and dilution mixing supplies the three pipes to the polishing pad. There is a method of connecting to one pipe and mixing in the pipe. In this case, it is possible to connect two pipes and then connect another 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, a means for heating and feeding other constituents in which the raw materials are dissolved and a means for stirring and feeding the liquid containing the precipitate and heating and dissolving the pipe are employed. can do. 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 polishing liquid 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 polishing liquid components into two or more parts and supplying them to the surface to be polished, the supply amount represents the total supply amount from each pipe. It is.

〔pad〕
The polishing pad for polishing applicable to the polishing method of 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 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 subjected to CMP with the polishing liquid 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 polishing liquid 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.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to them.

[Example 1]
A polishing liquid having the composition shown below was prepared and a polishing experiment was conducted.
<Composition (1)>
・ Abrasive: Colloidal silica 300g / L
(Secondary particle size: 65 nm, PL-3 manufactured by Fuso Chemical Industries)
Anticorrosive: benzotriazole (BTA) 2.0 g / L
・ Acid: Diglycolic acid 1g / L
・ Surfactant: Esoduomine T / 13 (manufactured by Lion Axo)
0.005g / L
Diquaternary cation: Exemplified compound A1 2.0 g / L
・ Pure water is added and the total volume is 1000mL
・ PH (adjusted with ammonia water and nitric acid) 3.5
・ Oxidizing agent: Hydrogen peroxide (30% solution) 35mL

(Evaluation method)
Using a device “F-REX 300” manufactured by Ebara Corporation as a polishing device, each wafer film shown below was polished under the following conditions while supplying slurry.
・ Table rotation speed: 90rpm
-Head rotation speed: 85rpm
Polishing pressure: 14.0 kPa
Polishing pad: IC1400-XY-k Groove (Rodel)
Polishing liquid supply speed: 300 ml / min

(Polishing rate evaluation: polishing object)
As a polishing object, a 12-inch wafer in which a Ta film, a TEOS film, and a SiOC film were formed on a Si substrate was used.

(Scratch evaluation: object to be polished)
A substrate on which a SiOC film is formed as an insulating film as an object to be polished and a TEOS film is subsequently formed is patterned by a photolithography process and a reactive ion etching process to form a wiring having a width of 0.09 to 100 μm and a depth of 600 nm Grooves and connection holes are formed, a Ta film having a thickness of 20 nm is formed by a sputtering method, a copper film having a thickness of 50 nm is subsequently formed by a sputtering method, and then a copper film having a total thickness of 1000 nm is formed by a plating method. A 12-inch wafer formed with was used.

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

<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.
-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 10 and Comparative Examples 1 to 3]
The composition (1) in Example 1 was changed to the composition described in Table 1 below, and polishing conditions similar to Example 1 were prepared using a polishing liquid prepared in the same manner as in Example 1 except for conditions described in Table 1. Polishing experiments were performed under the conditions. The results are shown in Table 2.

  The diquaternary ammonium cation A1 and the like described in Table 1 above refer to the aforementioned exemplary compounds.

Details of the compounds abbreviated in Table 1 are shown below.
Anticorrosive BTA: 1,2,3-benzotriazole DBTA: 5,6-dimethyl-1,2,3-benzotriazole DCEBTA: 1- (1,2-dicarboxyethyl) benzotriazole HMBTA: 1- (hydroxymethyl ) Benzotriazole

  Furthermore, the average primary particle size of the colloidal silica described in Table 1 is shown below. The colloidal silica of the present invention is all manufactured by Fuso Chemical Industries. The particle sizes of fumed silica and alumina in Table 1 are also average primary particle sizes.

PL-3: primary particle size 35 nm, degree of association 2
PL-3L: primary particle size 35 nm spherical PL-3H: primary particle size 35 nm degree of association 3
PL-2: Primary particle size 25 nm, degree of association 2
PL-2L: primary particle size 25 nm spherical

According to Table 2, when the polishing liquids of Examples 1 to 10 were used, it was possible to suppress the polishing rate of SiOC as compared with Comparative Examples 1 to 2, and to adjust the usage amount and the usage ratio to other films. It can be seen that the degree of suppression of the polishing rate can be controlled without changing the polishing rate of the seeds, and that the scratch performance is also excellent.
On the other hand, the polishing liquid of Comparative Example 1 does not have a big problem in scratch performance, but the polishing rate of SiOC cannot be suppressed. It can also be seen that the polishing liquid of Comparative Example 2 has a problem in scratch performance.

  From the above, it can be seen that the polishing liquid of the present invention is excellent not only in the Ta polishing rate but also in the TEOS and SiOC polishing rates and also in the scratch performance.

Claims (7)

Abrasive particles, at least one surfactant to have a two or more tertiary amino groups and one lipophilic portion represented by the following general formula (F), and a polishing composition comprising water:
Formula (F)

(In the formula, R represents at least one selected from an alkyl group having 6 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, and an aralkyl group, and x, y, and z are each an integer of 1 or more. N represents an integer of 1 or more . The polishing composition according to claim 1, wherein the abrasive particles are 0.05 to 30% by mass or less based on the mass of the polishing liquid used for polishing.   The polishing composition according to claim 1 or 2, wherein the abrasive particles are at least one selected from fumed silica, colloidal silica, ceria, and alumina. The polishing composition according to any one of claims 1 to 3, further comprising a compound represented by the following general formula (1) and / or a compound represented by the following general formula (2).

(In General Formula (1), R ^{1 to} R ⁴ each independently represents an alkyl group, alkenyl group, cycloalkyl group, aryl group, or aralkyl group having 1 to 20 carbon atoms. X ⁻ represents a monovalent group. In addition, any two of R ^{1 to} R ⁴ may be bonded to each other to form a cyclic structure.
In General Formula (2), R ^{5 to} R ¹⁰ each independently represent an alkyl group having 1 to 20 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, or an aralkyl group. M represents an alkylene group having 1 to 10 carbon atoms, an alkenylene group, a cycloalkylene group, an arylene group, or a group obtained by combining two or more thereof. X ⁻ represents a monovalent anion, and Y ²⁻ represents a divalent anion. Note that any two of R ^{5 to} R ¹⁰ may be bonded to each other to form a cyclic structure. )   The amount of the compound represented by the said general formula (F) is the range of 0.000001 mass%-20 mass%, Polishing composition of any one of Claims 2-4.   A polishing liquid comprising the polishing composition according to claim 1 is brought into contact with the surface to be polished, and the surface to be polished and the polishing means are moved relative to each other to perform polishing. A method of chemical mechanical polishing the surface.   A semiconductor device having at least one selected from the group consisting of TiN, TiW, Ta, TaN, W and WN polished by the polishing method according to claim 6 in a barrier layer.