JP5285866B2 - Polishing liquid - Google Patents

Description

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

  In the development of semiconductor devices typified by semiconductor integrated circuits (hereinafter referred to as “LSI”), in recent years, miniaturization and stacking of wiring have required higher density and higher integration in order to reduce the size and increase the speed. ing. 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”) that removes excess wiring material deposited by plating or the like is performed in one or more stages. Next, CMP is performed to remove the barrier metal material (barrier metal) exposed on the surface (hereinafter referred to as “barrier metal CMP”). 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 and silica) and an oxidizing agent (for example, hydrogen peroxide and persulfuric acid). It is considered that the basic mechanism is polishing by oxidizing the metal surface with an oxidizing agent and removing the oxide film with abrasive grains.
However, when CMP is performed using a polishing liquid containing such solid abrasive grains, scratches (scratches), a phenomenon in which the entire polished surface is polished more than necessary (thinning), and a phenomenon in which the polished metal surface bends in a dish shape. (Dishing), an insulator between metal wirings is polished more than necessary, and a plurality of wiring metal surfaces may be bent in a dish shape (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.
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 including an antistatic agent in the polishing liquid, and has achieved the object.
That is, the present invention provides the following polishing liquids (1) to (10) and the following polishing method (11).

(1) A polishing liquid for polishing a barrier layer of a semiconductor integrated circuit, which contains an antistatic agent.
Hereinafter, this may be referred to as “the polishing liquid of the first aspect of the present invention”.
(2) A polishing liquid for polishing a barrier layer of a semiconductor integrated circuit, comprising a compound represented by the following general formula (1).
Hereinafter, this may be referred to as “the polishing liquid of the second aspect of the present invention”.
Further, the polishing liquids of the first and second aspects of the present invention may be collectively referred to as “the polishing liquid of the present invention”.
Wherein R ¹ and R ² are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 6 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, an aralkyl group and a polyoxyethylene chain (EO). And at least one of R ¹ and R ² may be bonded to each other, and a is an integer of 1 or more.)
(3) The polishing liquid according to (2), wherein the concentration of the compound represented by the general formula (1) is 0.005 to 50 g / L with respect to the total mass of the polishing liquid.
(4) The polishing liquid according to any one of (1) to (3), further comprising a corrosion inhibitor and colloidal silica and having a pH of 2.5 to 5.0.
(5) The polishing liquid according to (4), wherein the concentration of the colloidal silica is 0.5 to 15% by mass with respect to the total mass of the polishing liquid.
(6) The polishing liquid according to (4) or (5), wherein the colloidal silica has a primary average particle size in the range of 20 to 50 nm.
(7) The corrosion inhibitor is 1,2,3-benzotriazole, 5,6-dimethyl-1,2,3-benzotriazole, 1- (1,2-dicarboxyethyl) benzotriazole, 1- [ N, N-bis (hydroxyethyl) aminomethyl] benzotriazole and at least one compound selected from the group consisting of 1- (hydroxymethyl) benzotriazole, according to any one of (4) to (6) above Polishing fluid.
(8) Further, in any one of the above (1) to (7), further comprising a diquaternary ammonium cation represented by the following general formula (2) or a monoquaternary ammonium cation represented by the following general formula (3) The polishing liquid as described.
[In General Formula (2) or General Formula (3), R ^{1 to} R ⁷ are each independently selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, and an aralkyl group. It represents at least one selected, and two of R ^{1 to} R ⁶ may be bonded to each other. X 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 obtained by combining these. ]
(9) The polishing liquid according to any one of (1) to (8), further comprising a compound having a carboxyl group, wherein the compound having the carboxyl group is a compound represented by the following general formula (4): .
[In General Formula (4), R ⁷ and R ⁸ each independently represents a hydrocarbon group. R ⁷ and R ⁸ may be bonded to each other to form a cyclic structure. ]
(10) The polishing liquid according to any one of (1) to (9), further comprising an anionic surfactant or a cationic surfactant.
(11) A polishing method using the polishing liquid according to any one of (1) to (10) above in polishing a barrier layer of a semiconductor integrated circuit.

Although the operation of the present invention is not clear, it is presumed as follows.
That is, it is thought that the charged state of the surface to be polished is controlled by the antistatic agent in the slurry adhering to the surface to be polished of the low-k film during polishing. More specifically, it is expected that the electrostatic affinity between the surface to be polished to which the antistatic agent is adhered and the abrasive particles are reduced. It is considered that the physical action (physical scratch removal action) between the pad abrasive particles and the surface to be polished is weakened due to the decrease in electrostatic affinity, and the polishing rate for the low-k film type is suppressed.

  The polishing liquid of the present invention maintains the polishing rate for the film to be polished at the time of polishing the barrier layer at a high polishing rate, and sufficiently suppresses the polishing rate for a low-k low-k film. Can do.

Hereinafter, specific embodiments of the present invention will be described.
The polishing liquid according to the first aspect of the present invention is a polishing liquid for polishing a barrier layer of a semiconductor integrated circuit, and contains an antistatic agent.

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.

[Antistatic agent]
The polishing liquid according to the first aspect of the present invention contains an antistatic agent.
The antistatic agent contained in the polishing liquid according to the first aspect of the present invention may be a known document or the like (for example, “Technology and Application of Antistatic Materials” (CMC Publishing), “Oil Chemistry Dictionary, Lipid / Surfactant” ( Maruzen), “Surfactant Function and Utilization Technology” (spread version), “Surfactant Physical Properties and Performance Guide” (Technical Information Association)), and there is no particular limitation.
Especially, it is preferable that it is a compound represented by following General formula (1) from a viewpoint of achieving suppression of more sufficient polishing rate.

Wherein R ¹ and R ² are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 6 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, an aralkyl group and a polyoxyethylene chain (EO). And at least one of R ¹ and R ² may be bonded to each other, and a is an integer of 1 or more.)
The compound represented by the general formula (1) will be described in detail in the polishing liquid according to the second aspect of the present invention.
Antistatic agents can be used alone or in combination of two or more.

  The amount of the antistatic agent added 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) 0.005 g / L or more and 50 g / L or less is preferable, and 0.01 g / L or more and 30 g / L or less is more preferable. That is, the addition amount of the antistatic agent is preferably 0.005 g / L or more from the viewpoint of sufficiently suppressing the polishing rate, and is preferably 50 g / L or less from the viewpoint of not inhibiting the polishing rate for other film types.

The polishing liquid according to the first aspect of the present invention may further include, for example, abrasive particles, corrosion inhibitors, colloidal silica, quaternary ammonium salts, compounds having a carboxyl group, anionic surfactants, positive ions, if necessary. Arbitrary components, such as an ionic surfactant, may be included.
The optional components will be described in detail in the polishing liquid of the second aspect of the present invention.
Each component contained in the polishing liquid of the first aspect of the present invention may be used alone or in combination of two or more.

Next, the polishing liquid according to the second aspect of the present invention will be described below.
The polishing liquid according to the second aspect of the present invention is a polishing liquid for polishing a barrier layer of a semiconductor integrated circuit, and contains a compound represented by the following general formula (1). is there.

Wherein R ¹ and R ² are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 6 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, an aralkyl group and a polyoxyethylene chain (EO). And at least one of R ¹ and R ² may be bonded to each other, and a is an integer of 1 or more.)

In the general formula (1), R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 6 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, an aralkyl group, and a polyoxyethylene chain (EO). Represents at least one selected from the group consisting of R ¹ and R ² , and a is an integer of 1 or more.

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 range of molecular weight 100-10,000 is preferable, and the range of molecular weight 200-5,000 is 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.

  A in the general formula (1) is an integer of 1 or more from the viewpoint of sufficiently suppressing the polishing rate for the target film, and 1 to 50 from the viewpoint of sufficiently suppressing the polishing speed for the target film. It is preferably an integer.

  Hereinafter, although the preferable specific example (Exemplary compound D-1 to D-23) of the compound represented by General formula (1) in this invention is shown, this invention is not limited to these.

In the above-mentioned D5 to D8, D13 to D16 and D20, b is preferably an integer of 1 to 100, preferably an integer of 1 to 50, from the viewpoint of sufficiently exhibiting the effect of the additive. Is more preferable.
In particular, the compound represented by the general formula (1) maintains a higher polishing rate for the film to be polished when the barrier layer is polished, and has a lower dielectric constant for a low-k film. D1, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11, D12, D13, D14, D15, and D16 are preferable because the polishing rate can be more sufficiently suppressed.
The compounds represented by the general formula (1) can be used alone or in combination of two or more.

  The amount of the compound represented by the general formula (1) 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 polishing liquid at the time” is also agreed.) Is preferably 0.005 g / L or more and 50 g / L or less, more preferably 0.01 g / L or more and 30 g / L or less. That is, the amount of the compound represented by the general formula (1) is preferably 0.005 g / L or more from the viewpoint of sufficiently suppressing the polishing rate, and 50 g from the viewpoint of not inhibiting the polishing rate for other film types. / L or less is preferable.

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

Examples of the corrosion inhibitor that can be used in the present invention include benzotriazole, 1,2,3-benzotriazole, 5,6-dimethyl-1,2,3-benzotriazole, and 1- (1,2-dicarboxyethyl). ) Benzotriazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] benzotriazole, 1- (hydroxymethyl) benzotriazole and the like.
Among them, from the viewpoint of sufficiently suppressing the corrosion of wiring, 1,2,3-benzotriazole, 5,6-dimethyl-1,2,3-benzotriazole, 1- (1,2-dicarboxyethyl) benzo It is preferably selected from triazole, 1- [N, N-bis (hydroxyethyl) aminomethyl] benzotriazole and 1- (hydroxymethyl) benzotriazole.
A corrosion inhibitor can be used individually or in combination of 2 types or more, respectively.

  The addition amount of the corrosion inhibitor is preferably 0.01 g / L or more and 2 g / L or less, and more preferably 0.05 g / L or more and 2 g / L with respect to the mass of the polishing liquid used for polishing. That is, the addition amount of the corrosion inhibitor is preferably 0.01 g / L or more from the viewpoint of not expanding dishing, and preferably 0.2 g / L or less from the viewpoint of storage stability.

[Colloidal silica]
The polishing liquid of this invention is mentioned as one of the aspects with preferable colloidal silica containing at least one part of an abrasive grain.
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.
Colloidal silica can be used alone or in combination of two or more.
The particle size of the colloidal silica is appropriately selected according to the purpose of use of the abrasive grains, but is generally about 10 to 200 nm, but from the viewpoint of not causing polishing scratches, it may be in the range of 20 to 50 nm. preferable.

  The content (concentration) of colloidal silica in the polishing liquid of the present invention is preferably 0.5% by mass or more and 15% by mass or less, more preferably 3%, based on the mass of the polishing liquid used for polishing. It is not less than 12% by mass and particularly preferably not less than 5% by mass and not more than 12% by mass. That is, the content of colloidal silica is preferably 0.5% by mass or more in terms of polishing the barrier layer at a sufficient polishing rate, and is preferably 15% by mass or less in terms of storage stability.

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

[Diquaternary ammonium cation, monoquaternary ammonium cation]
The polishing liquid of the present invention further contains at least one selected from the group consisting of a diquaternary ammonium cation and a monoquaternary ammonium cation (hereinafter, this may be simply referred to as “specific cation”). May be.
The diquaternary ammonium cation 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 monoquaternary ammonium cation is not particularly limited as long as it has a structure containing one quaternary nitrogen in the chemical structure.
The specific cation is preferably a diquaternary ammonium cation or a monoquaternary ammonium cation from the viewpoint of achieving a sufficient polishing rate improvement.
Examples of the diquaternary ammonium cation include a cation represented by the following general formula (2).
Examples of the monoquaternary ammonium cation include a cation represented by the following general formula (3).
Among these, from the viewpoint of achieving a sufficient improvement in the polishing rate, either or both of a cation represented by the following general formula (2) and a cation represented by the general formula (3) are preferable.

[In General Formula (2) or General Formula (3), R ^{1 to} R ⁷ are each independently selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, and an aralkyl group. It represents at least one selected, and two of R ^{1 to} R ⁶ may be bonded to each other. X 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 obtained by combining these. ]

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, butyl group and cyclohexyl 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.

X 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.
In addition to the organic linking group described above, the linking group represented by X includes —S—, —S (═O) ₂ —, —O—, —C (═O) — in the chain. 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.

  Hereinafter, specific examples of diquaternary ammonium cations (Exemplary Compounds A-1 to A-32) and monoquaternary ammonium cations (Exemplary Compounds A-33 to A-44) that can be contained in the polishing liquid of the present invention. Although a specific example is shown, this 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.

[Compound having a carboxyl group]
The polishing liquid of the present invention further contains a compound having a carboxyl group (hereinafter appropriately referred to as “organic acid”) from the viewpoint of achieving a sufficient polishing rate for films other than the low dielectric constant film type. It is preferable to do. 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 a compound represented by the following general formula (4) is selected from the viewpoint of the polishing rate structure. Is preferred.
In addition, it is preferable that the number of the carboxyl groups which exist in a molecule | numerator is 1-4, and it is more preferable that it is 1-2 from a viewpoint which can be used cheaply.

In the general formula (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, a cycloalkylene group, etc.), 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 and the like. In addition, when it has a carboxyl group as a substituted group which the hydrocarbon group represented by R ⁷ and R ⁸ can further have, 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 cyclic structure include a furan ring and a tetrahydrofuran ring.

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.
The compound which has a carboxyl group can be used individually or in combination of 2 types or more, respectively.

  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 g / mass with respect to the mass of the polishing liquid used for polishing. L or more and 50 g / L or less are preferable, and 0.05 g / L or more and 20 g / L or less are more preferable. That is, the content of such a compound having a carboxyl group (organic acid) is preferably 0.01 g / L or more from the viewpoint of achieving a sufficient polishing rate, and 50 g / L from the point of not causing excessive dishing. The following is preferred.

[Surfactant]
The polishing liquid of the present invention is further mentioned as one of preferred embodiments that further contain a surfactant.
In the polishing liquid of the present invention, the polishing rate can be improved and the polishing rate of the insulating layer can be controlled by adjusting the type and amount of the surfactant. As the surfactant, an anionic surfactant or a cationic surfactant is preferably used.
As an anionic surfactant, the compound represented by following General formula (5) is mentioned, for example.
Examples of the cationic surfactant include a compound represented by the following general formula (6).
Among these, from the viewpoint of improving the polishing rate of the insulating layer, a compound represented by the following general formula (5) is preferable, and from the viewpoint of suppressing the polishing rate of the insulating layer, a compound represented by the following general formula (6) is preferable. preferable.

In the general formula (5), R represents a hydrocarbon group, and preferably represents a hydrocarbon group having 6 to 20 carbon atoms.
Specifically as a C6-C20 hydrocarbon group, a C6-C20 alkyl group, an aryl group (for example, a phenyl group, a naphthyl group, etc.) etc. are preferable, for example, This alkyl group or aryl group is preferable. May further have a substituent such as an alkyl group.

  Specific examples of the compound represented by the general formula (5) include, for example, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, hexadecylbenzenesulfonic acid, dodecylnaphthalenesulfonic acid, tetradecylnaphthalenesulfonic acid. And the like.

In the general formula (6), R ^{a to} R ^d each independently represent a hydrocarbon group having 1 to 18 carbon atoms. However, R ^{a to} R ^d are not all the same hydrocarbon group.
Examples of the hydrocarbon group represented by R ^{a to} R ^d include an alkyl group, an aryl group, and a phenyl group, and among them, a linear and branched alkyl group having 1 to 20 carbon atoms is preferable.
Two of R ^{a to} R ^d may be bonded to each other to form, for example, a cyclic structure such as a pyridine structure, a pyrrolidine structure, a piperidine structure, or a pyrrole structure.

  Specific examples of the compound represented by the general formula (6) include compounds such as lauryltrimethylammonium, lauryltriethylammonium, stearyltrimethylammonium, palmityltrimethylammonium, octyltrimethylammonium, dodecylpyridinium, decylpyridinium, octylpyridinium, and the like. Is mentioned.

As the surfactant in the present invention, other than the compound represented by the general formula (5) or (6), an anionic interface other than the compound represented by the general formula (5) may be used. Examples of the activator include carboxylate, sulfate ester salt, and phosphate ester salt.
More specifically, examples of the carboxylate include soap, N-acyl amino acid salt, polyoxyethylene or polyoxypropylene alkyl ether carboxylate, and acylated peptide;
Examples of sulfate salts include sulfated oils, alkyl sulfates, alkyl ether sulfates, polyoxyethylene or polyoxypropylene alkyl allyl ether sulfates, and alkylamide sulfates;
As the phosphate ester salt, for example, alkyl phosphate, polyoxyethylene or polyoxypropylene alkylallyl ether phosphate can be preferably used.
The surfactants can be used alone or in combination of two or more.

  The total amount of the surfactant added is preferably 0.001 to 10 g, more preferably 0.01 to 5 g in 1 liter of polishing liquid when used for polishing. It is particularly preferable that That is, the addition amount of the surfactant is preferably 0.01 g or more for obtaining a sufficient effect, and preferably 1 g or less from the viewpoint of preventing the CMP rate from being lowered.

[Body components]
The polishing liquid of the present invention can further contain an additive as long as the effects and objects of the present invention are not impaired. As an additive, an oxidizing agent, a pH adjuster, a chelating agent etc. are mentioned, for example.
(Oxidant)
The polishing liquid of the present invention is further mentioned as one of the preferred embodiments containing a compound (oxidant) that can oxidize 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, in addition to inorganic iron (III) salts such as iron nitrate (III), iron chloride (III), iron sulfate (III), iron bromide (III), and iron (III) Organic complex salts are preferably used.

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

(PH adjuster)
From the viewpoint of achieving a high polishing rate, the polishing liquid of the present invention preferably has a pH of 2.5 to 5.0, and more preferably a pH of 3.0 to 4.5. When the pH of the polishing liquid is controlled within this range, the polishing rate of the interlayer insulating film can be adjusted more remarkably, and a particularly excellent effect is exhibited.
In order to adjust the pH to the above preferred range, an alkali / acid or buffer can be used.
Examples of alkali / acid or buffering agents include organic ammonium hydroxides such as ammonia, ammonium hydroxide and tetramethylammonium hydroxide; nonmetals such as alkanolamines such as diethanolamine, triethanolamine and triisopropanolamine Alkaline agents; 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; Preferable examples include borate, tetraborate, and hydroxybenzoate. Particularly preferred alkaline agents are ammonium hydroxide, potassium hydroxide, lithium hydroxide and tetramethylammonium hydroxide.

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

(Chelating agent)
The polishing liquid of the present invention preferably further 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.
Examples of the chelating agent include general-purpose water softeners and related compounds that are precipitation inhibitors of calcium and magnesium, and specific examples thereof include 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 orthohydroxyphenyl Acetic acid, ethylenediamine disuccinic acid (SS form), N- (2-carboxylate ethyl) -L-aspartic acid, β-alanine diacetic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1-hydroxyethylidene-1 , 1-Diphosphonic acid, N, N ' Bis (2-hydroxybenzyl) ethylenediamine -N, N'-diacetic acid, 1,2-dihydroxy-4,6-disulfonic acid.

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

The polishing liquid of the present invention is not particularly limited for its production. For example, an antistatic agent or a compound represented by the general formula (1) and a corrosion inhibitor, colloidal silica, diquaternary ammonium cation or monoquaternary ammonium cation, organic acid, which can be used as necessary, It can be obtained by mixing a surfactant, an additive and water.
In addition, the polishing liquid of the present invention can be used as an embodiment in which, for example, 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 later, these are mixed, and if necessary diluted with water to make a working solution. The case where it is prepared as a use liquid is mentioned.

  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.

Next, the polishing method of the present invention will be described below.
The polishing method of the present invention is a polishing method using the polishing liquid of the present invention in polishing a barrier layer of a semiconductor integrated circuit.

The polishing liquid used in the polishing method of the present invention is not particularly limited as long as it is the polishing liquid of the present invention.
The semiconductor integrated circuit used in the polishing method of the present invention is not particularly limited as long as it has a barrier layer.
In the polishing method of the present invention, the polishing of the barrier layer of the semiconductor integrated circuit is one of the preferred embodiments that is CMP.
[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 good, and Ru, RuO4, TiN, TiW, Ta, TaN, W, WN are particularly preferable. Ta, TaN, Ru, and RuO4 are particularly preferable.

[Interlayer insulation film]
Examples of the interlayer insulating film to be polished by the polishing liquid of the present invention include a generally 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, , Organic polymer-based, SiOC-based, SiOF-based, etc., which are usually abbreviated as Low-k films).
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]
In the polishing method of the present invention, the polishing liquid is used in the following manner. 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. The case where it is prepared as a use liquid is mentioned.
The polishing liquid in any case can be applied to the polishing method of the present invention.
The polishing method of the present invention is preferably a method in which a polishing liquid is supplied to a polishing pad on a polishing surface plate and brought into contact with the surface to be polished of the object to be polished so that the surface to be polished and the polishing pad move relative to each other. One of them.

  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 can be continuously supplied to the polishing pad with a pump 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 concentrate, for example, a pipe for supplying a concentrated polishing liquid and a pipe for supplying water or an aqueous solution are merged and mixed, mixed and diluted. There is a method of supplying a working liquid of the polishing liquid to the polishing pad. Mixing of concentrated liquid with water or aqueous solution is a method in which liquids collide with each other through a narrow passage under pressure, filling the pipe with a filler such as a glass tube, and separating and separating the liquid flow. Ordinary methods such as a method of repeatedly performing and a method of providing a blade rotating with power in the pipe can be employed.

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

  Furthermore, as a method of polishing while diluting the concentrated liquid with water or an aqueous solution, for example, a pipe for supplying the polishing liquid and a pipe for supplying water or an aqueous solution are provided independently, and a predetermined amount of liquid is polished from each. There is a method of polishing while supplying to the pad and mixing by the relative movement 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 oxidizing agent is used as the constituent component (A), and an antistatic agent or a compound represented by the general formula (1), an organic acid, an additive, a surfactant, and water are used as the constituent component (B). When using them, the component (A) and the component (B) can be diluted with water or an aqueous solution and used.
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 antistatic agent or a general formula The compound represented by (1), an organic acid, an additive, a surfactant, and water are used as the constituent component (B), and when they are used, water or an aqueous solution is added to the constituent component (A). And dilute 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, there are provided means for heating and feeding the other constituents in which the raw material is dissolved, and means for stirring and feeding the liquid containing the precipitate, and heating and dissolving the piping. Can be adopted. When the temperature of one constituent component containing an oxidizing agent is increased to 40 ° C. or higher, the other constituent components that have been heated may be decomposed. When two components are mixed, it is preferable that the temperature be 40 ° C. or lower.

Thus, in the present invention, the components of the 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 polishing method of 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, and 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]
The apparatus capable of performing polishing using the polishing liquid of the present invention is not particularly limited. For example, 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.

In the polishing method of the present invention, the polished object (for example, a wafer) is thoroughly washed in running water after polishing, and water droplets adhering to the object to be polished are removed by using a spin dryer or the like, followed by drying. After drying, the semiconductor integrated circuit can be cut, for example, by a conventionally known method.
The semiconductor integrated circuit polished by the polishing liquid of the present invention has a flat polished surface and almost no barrier layer.

  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)>
Antistatic agent: Compound represented by D-1, 0.8 g / L
Diquaternary ammonium cation: hexamethonium chloride, 0.2 g / L
Corrosion inhibitor: benzotriazole (BTA), 0.5 g / L
Colloidal silica: secondary particle diameter: 65 nm, PL3 slurry, manufactured by Fuso Chemical Industries, 200 g / L
Compound having a carboxyl group: Diglycolic acid (manufactured by Wako Pure Chemical Industries, Ltd.), 1 g / L
・ Total amount of pure water added: 1000 mL, pH 3.5 (adjusted with aqueous ammonia and nitric acid)
・ Oxidizing agent: 30% hydrogen peroxide solution, 10 ml

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

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

<Polishing speed>
The polishing rate was determined by measuring the film thicknesses of the Ta film (barrier layer), TEOS film (insulating film), and SiOC (BD-II) 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.

[Examples 2-35 and Comparative Examples 1-2]
Polishing experiments were performed under the same polishing conditions as in Example 1, using a polishing liquid prepared by changing the composition (1) in Example 1 to the compositions shown in Tables 1 to 3 below. The results are shown in Tables 1 to 3.

  D-1 to D-23 and A-1 to A-45 described in Tables 1 to 3 above refer to the exemplary compounds described above.

Details of the compounds abbreviated in Tables 1 to 3 are shown below.
Corrosion inhibitor BTA: 1,2,3-benzotriazole DBTA: 5,6-dimethyl-1,2,3-benzotriazole DCEBTA: 1- (1,2-dicarboxyethyl) benzotriazole HEABTA: 1- [N , N-bis (hydroxyethyl) aminomethyl] benzotriazole HMBTA: 1- (hydroxymethyl) benzotriazole

Surfactant DBS: Dodecylbenzenesulfonic acid DNS: Dodecylnaphthalenesulfonic acid LTM: Lauryltrimethylammonium nitrate DP: Dodecylpyridinium nitrate

  Further, the shapes and primary particle sizes of the colloidal silicas C-1 to C-5 described in Tables 1 to 3 are shown in Table 4 below. All colloidal silicas listed in Table 4 below are manufactured by Fuso Chemical Industries.

  The compound names of the compounds (organic acids) B-1 to B-5 having a carboxyl group described in Tables 1 to 3 are shown in Table 5 below.

According to Tables 1 to 3, when the polishing liquids of Examples 1 to 35 were used, Ta and TEOS polishing rates were higher than those of Comparative Examples 1 and 2, and a sufficiently low-k film was used. It can be seen that the polishing rate for is suppressed.
On the other hand, although the polishing liquid of Comparative Example 1 has no problem in the polishing rate of Ta and TEOS, it can be seen that the polishing rate for the low-k film is not suppressed. Further, it can be seen that the polishing liquid of Comparative Example 2 has a low Ta and TEOS polishing rate and a very high polishing rate for the low-k film.

  From the above, it can be seen that the polishing liquid of the present invention is excellent in Ta and TEOS polishing rates, and the polishing rate for the low-k film is sufficiently suppressed.

Claims (14)

A polishing liquid for polishing a barrier layer of a semiconductor integrated circuit,
A compound represented by the following general formula (1) :
A diquaternary ammonium cation represented by the following general formula (2) or a monoquaternary ammonium cation represented by the following general formula (3),
Colloidal silica, and
A polishing liquid comprising a compound having a carboxyl group .
Wherein R ¹ and R ² are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 6 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, an aralkyl group and a polyoxyethylene chain (EO). And each group may have a substituent, R ¹ and R ² may be bonded to each other, and a is an integer of 1 or more.)
[In General Formula (2) or General Formula (3), R ^{1 to} R ⁷ are each independently selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, and an aralkyl group. It represents at least one selected, and two of R ^{1 to} R ⁶ may be bonded to each other. X 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 obtained by combining these. ] In the general formula (1), R ² is at least 1 selected from the group consisting of an alkyl group having 6 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, an aralkyl group, and a polyoxyethylene chain (EO). The polishing liquid according to claim 1, which represents a seed. In the general formula (1), R ¹ is at least 1 selected from the group consisting of an alkyl group having 6 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, an aralkyl group, and a polyoxyethylene chain (EO). The polishing liquid according to claim 1 or 2, which represents a seed. The said General formula (1) WHEREIN: Either ^{one of} said R <1> or R < ² > is a C6-C30 alkyl group or a polyoxyethylene chain (EO), The any one of Claims 1 thru | or 3 The polishing liquid described in 1. In Formula (1), both of the R ¹ or R ^2, according to any one of claims 1 through claim 4 is an alkyl group or a polyoxyethylene chain C6-30 (EO) Polishing liquid. The compound represented by the general formula (1) is according to any one of the following formulas (D1) ~ claims 1 to 5 is at least one selected from the group consisting of the following formulas (D23) Polishing fluid.
(In the above formula, a is an integer of 1 or more, and b in the above D5 to D8, D13 to D16 and D20 is an integer of 1 to 100.) The polishing liquid according to claim 1 , wherein the concentration of the compound represented by the general formula (1) is 0.005 to 50 g / L with respect to the total mass of the polishing liquid. The polishing liquid according to claim 1 , wherein the concentration of the colloidal silica is 0.5 to 15% by mass with respect to the total mass of the polishing liquid. The polishing liquid according to any one of claims 1 to 8, wherein the colloidal silica has a primary average particle diameter in a range of 20 to 50 nm. The polishing liquid according to claim 1 , further comprising a corrosion inhibitor and having a pH of 2.5 to 5.0. The corrosion inhibitor is 1,2,3-benzotriazole, 5,6-dimethyl-1,2,3-benzotriazole, 1- (1,2-dicarboxyethyl) benzotriazole, 1- [N, N The polishing liquid according to claim 10 , which is at least one compound selected from the group consisting of -bis (hydroxyethyl) aminomethyl] benzotriazole and 1- (hydroxymethyl) benzotriazole. The polishing liquid according to any one of compound claims 1 to 11 which is a compound represented by the following general formula (4) having a carboxyl group.
[In General Formula (4), R ⁷ and R ⁸ each independently represents a hydrocarbon group. R ⁷ and R ⁸ may be bonded to each other to form a cyclic structure. ] The polishing liquid according to any one of claims 1 to 12 , further comprising an anionic surfactant or a cationic surfactant. 14. A polishing method using the polishing liquid according to claim 1 in polishing a barrier layer of a semiconductor integrated circuit.