JP2009131944A - Conductive polishing pad and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive polishing pad and its manufacturing method reducing scratches in polishing. <P>SOLUTION: The conductive polishing pad includes a conductive member C formed in a manner that a conductive polymer B having a sulfonate group and/or a carboxyl group adheres to a backing A for the polishing pad. The conductive polishing pad includes the conductive member C formed in a manner that the conductive polymer B having the sulfonate group and/or the carboxyl group adheres to a backing A' formed in a manner that a compound D having more than one amino group adheres to the backing A for the polishing pad. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a conductive polishing pad and a method for manufacturing the same.

Semiconductor devices typified by semiconductor integrated circuits (LSIs) are required to have molecular-atomic level flatness as the surface flatness when forming each layer in order to achieve high integration and high speed. It has come to be.
A key technique for forming this multilayer wiring structure with high productivity is a polishing (planarization) technique called chemical mechanical polishing (hereinafter referred to as CMP). In other words, the CMP technology for semiconductors refers to the use of chemical polishing agents, polishing pads, etc., to remove unnecessary irregularities of materials on the wafer (insulating thin films such as silicon oxide and metal thin films for wiring) generated in the semiconductor manufacturing process. This is a technique of removing and flattening by a combination of chemical action and mechanical polishing action.

On the other hand, in recent years, in order to further reduce the dielectric constant of an interlayer insulating film (hereinafter referred to as a low-k film), a conventional method of doping carbon into a silicon oxide film, and making a low-k film porous. Methods are being studied. However, in any of the methods, the mechanical strength and chemical stability of the low-k film are lowered, which causes problems such as separation of the wiring material from the low-k film in the CMP process. To do. In the CMP process, scratches on (copper) wiring (scratches due to polishing) are also a problem.
For this reason, there is a strong demand for “low-pressure polishing” in the CMP process, and there is an urgent need for further advancement of CMP technology in conjunction with reduction of wiring scratches and the like.

In order to realize “low-pressure polishing”, a method that uses an electrochemical action, so-called electrolytic polishing, is now being actively studied.
Generally, in the current CMP, the polishing rate (corresponding to productivity) is almost proportional to the polishing pressure (pressure to press the polishing head (wafer) against the surface plate (the polishing pad attached on the surface plate)). “Lower pressure” leads to lower productivity.
Electropolishing is a processing method in which copper is ionized and electrochemically etched by applying a voltage to the copper film in the wiring layer (copper film), and the polishing speed is controlled by the voltage. Do not depend. Therefore, it is possible to perform “low pressure polishing” while compensating for the decrease in productivity due to “low pressure” and improving productivity.
As a method of electrolytic polishing, a method of performing only electrolytic polishing, a method of simultaneously performing electrolytic polishing and CMP, and the like have been proposed. When only electrolytic polishing is performed, even if the wiring material can be removed, flattening is hardly expected, and when CMP is performed in a separate process in addition to electrolytic polishing, there is a problem that the apparatus becomes large. For this reason, the practical use of electrochemical mechanical polishing (hereinafter referred to as ECMP) in which electrolytic polishing and CMP are performed simultaneously is expected.

In electrolytic polishing, the copper wiring material on the wafer surface is used as an anode, a cathode is provided by some method, and a direct current must be passed between them by some method. In electropolishing, there are many cases where a platen (platen) of a CMP polishing apparatus is used as a cathode due to structural problems of the apparatus. In this case, an interelectrode gap for electropolishing is mainly formed between the copper wiring material (anode) and the platen (cathode) on the wafer surface, and the polishing pad is located between them. . However, since the conventional polishing pad is usually made of an insulating material such as a resin (usually having a thickness of 1 mm to 3 mm), the gap between the electrodes is too large in the conventional polishing pad, so that it is practically electrolyzed. Polishing cannot be carried out.
For this reason, for example, there is a method (for example, Patent Document 1) in which a plurality of through holes are provided in a polishing pad that is an insulator, and an electrolytic solution is filled so as to be in contact with the anode (wiring material) and the cathode (platen). Proposed.
In addition, attempts have been made to make the polishing pad itself conductive (for example, Patent Document 2). As a method of making the polishing pad itself conductive, a method of physically mixing a conductive material such as a metal-based conductive material, carbon black, or conductive polymer into the polishing pad base material, or producing a polishing pad with conductive fibers. A method is illustrated.
JP 2006-332526 A JP 2004-111940 A

However, when a plurality of through holes are provided in a polishing pad that is an insulator, the effect of flattening the polishing surface can hardly be expected. Therefore, it is difficult to perform electropolishing and CMP (planarization) at the same time.
Further, in the case of a method of physically mixing a conductive material into a polishing pad base material, there is a problem that (copper) wiring scratches easily occur due to the conductive material in the CMP process. In addition, the conductive material may fall off during polishing.
This invention is made | formed in view of the said situation, Comprising: It aims at providing the electroconductive polishing pad which can reduce the scratch at the time of grinding | polishing, and its manufacturing method.

The 1st aspect of this invention which solves the said subject is a conductive member (A) in which the conductive polymer (B) which has a sulfonic acid group and / or a carboxy group adheres to the base material (A) for polishing pads. A conductive polishing pad having C).
In the second aspect of the present invention, a sulfonic acid group and / or a carboxy group is formed on a base material (A ′) formed by attaching a compound (D) having two or more amino groups to a base material (A) for a polishing pad. It is an electroconductive polishing pad which has the electroconductive member (C) formed by adhering the electroconductive polymer (B) which has.
In the third aspect of the present invention, the substrate (A) for the polishing pad is immersed in a liquid containing a compound (D) having two or more amino groups, and the obtained substrate (A ′) is electrically conductive. A method for producing a conductive polishing pad comprising a step of obtaining a conductive member (C) by immersing in a liquid containing a conductive polymer (B).

  ADVANTAGE OF THE INVENTION According to this invention, the electroconductive polishing pad which can reduce the scratch at the time of grinding | polishing, and its manufacturing method can be provided.

Hereinafter, the present invention will be described in detail.
[Base material for polishing pad (A)]
The substrate (A) for the polishing pad may be the polishing pad itself or a precursor thereof (such as a raw material for the polishing pad substrate).
When the polishing pad itself is used as the base material (A) for the polishing pad, a conventionally known one can be used as the polishing pad.
There is no restriction | limiting in particular as a form of a polishing pad, For example, a nonwoven fabric type, a plate type (type which does not contain a foam layer), a foaming type etc. can be illustrated. In particular, the foam type is preferable because it is effective in reducing wiring scratches.
Examples of the precursor of the polishing pad include a raw material for the polishing pad substrate, and specific examples thereof include the same materials as those constituting the polishing pad substrate (A) described below. it can.
Examples of the material constituting the base material (A) for the polishing pad include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyester such as aromatic polyester, polylactic acid, polyether ester; polyester polyol, polyether ester polyol, etc. Polyurethane obtained by reacting the polyol and polyisocyanate can be exemplified. Particularly preferred is a polyurethane foam obtained by reacting the polyol with a polyisocyanate.
The base material (A) for the polishing pad may contain a compound other than the exemplified resins as long as the effects of the present invention are not impaired.
The base material (A) for the polishing pad may contain known additives such as an antioxidant, an ultraviolet absorber, a filler, a lubricant, a plasticizer, and a stabilizer as necessary.

[Base Material (A ′)]
The base material (A ′) is obtained by adhering a compound (D) having two or more amino groups to the base material (A) for the polishing pad. The conductive polymer (B) is likely to adhere to the base material (A ′) via the compound (D).
Examples of the compound (D) include diaminomethane, diaminoethane, diaminopropane, diaminobutane, diaminopentane, diaminohexane, diaminoheptane, diaminooctane, diaminononane, diaminododecane, diaminododecane, and other alkyldiamines; 4,4′-diaminodiphenylmethane 4,4′-diaminodiphenyl ether, 4,4′-bis (4-aminophenoxy) biphenyl, 1,4′-bis (4-aminophenoxy) benzene, 1,3′-bis (4-aminophenoxy) benzene (TPE-R), o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4-diaminodiphenyl sulfone, 3,3 ' -Diaminodiph Nilsulfone, 4,4′-methylene-bis (2-chloroaniline), 3,3′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diaminodiphenyl sulfide, 2,6′-diaminotoluene, 2,4-diaminochlorobenzene, 1,2-diaminoanthraquinone, 1,4-diaminoanthraquinone, 3,3′-diaminobenzophenone, 3,4-diaminobenzophenone, 4,4′-diaminobenzophenone, 4,4′-diamino Aromatic diamines such as bibenzyl, R (+)-2,2′-diamino-1,1′-binaphthalene, S (+)-2,2′-diamino-1,1′-binaphthalene; 1,4- Such as diaminocyclohexane, 1,2-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 4,4′-diaminodicyclohexylmethane, etc. Alicyclic diamine; 3,4-diaminopyridine, can be exemplified 1,4-diamino-2-butanone.

The base material (A ′) can be produced, for example, by immersing the base material (A) for the polishing pad in a liquid containing the compound (D) (hereinafter referred to as “treatment liquid (1)”).
As the treatment liquid (1), when the compound (D) is a liquid, the compound (D) may be used as it is, or a solution obtained by diluting the compound (D) with a solvent may be used.
When the compound (D) is a solid or a viscous liquid, a solution obtained by dissolving the compound (D) in a solvent is used as the treatment liquid (1).
Examples of the solvent include water; a mixed solvent of water and an organic solvent soluble in water. An organic solvent being “soluble in water” means forming a uniform solution when mixed with water.
Examples of water-soluble organic solvents include alcohols such as methanol, ethanol, isopropyl alcohol, propyl alcohol, and butanol; ketones such as acetone and ethyl isobutyl ketone; ethylene glycols such as ethylene glycol and ethylene glycol methyl ether; propylene Propylene glycols such as glycol, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, propylene glycol propyl ether; amides such as N, N-dimethylformamide and N, N-dimethylacetamide; N-methylpyrrolidone, N -Pyrrolidones such as ethyl pyrrolidone and the like can be mentioned. Any of these may be used alone or in combination of two or more.
As the solvent of the treatment liquid (1), water or a mixed solvent of water and alcohols is preferable.

The amount of the treatment liquid (1) used is preferably such that the amount of the compound (D) in the treatment liquid (1) is 1 part by mass or more with respect to 100 parts by mass of the base material (A) to be immersed. The amount of at least part by mass is more preferred, and more preferably at least 10 parts by mass. When the amount of the compound (D) is 1 part by mass or more, a sufficient amount of the compound (D) adheres to the substrate (A).
The amount of the treatment liquid (1) used is preferably such that the amount of the compound (D) in the treatment liquid (1) is 10000 parts by mass or less with respect to 100 parts by mass of the substrate (A) to be immersed. An amount of 5000 parts by mass or less is more preferable.
As for content of the compound (D) in a processing liquid (1), 1-100 mass% is preferable with respect to the total mass (100 mass%) of a processing liquid (1). Within this range, the compound (D) can be efficiently attached to the substrate (A).

Immersion may be performed at room temperature, or heat treatment may be performed simultaneously with the immersion. By performing the heat treatment, the adhesion of the compound (D) to the base material (A) for the polishing pad can be accelerated.
The temperature of the heat treatment, that is, the immersion temperature is preferably 20 ° C. or higher.
The upper limit of the immersion temperature depends on the type of material of the base material (A) for the polishing pad and cannot be determined unconditionally, and may be appropriately determined according to the material. The temperature at which the base material (A) for the polishing pad does not deform or deteriorate is preferred.

What is necessary is just to adjust suitably the time (immersion time) which immerses the base material (A) for polishing pads in a process liquid (1) with a desired electrical conductivity level. By adjusting the immersion time, the amount of the compound (D) attached to the base material (A) for the polishing pad can be adjusted. The adhesion amount of the conductive polymer (B) can be increased as the adhesion amount of the compound (D) to the substrate (A) for the polishing pad is increased.
The time for immersing the substrate (A) in the treatment liquid (1) is usually preferably 5 minutes or more, more preferably 10 minutes or more, and further preferably 60 minutes or more. Moreover, 300 minutes or less are preferable and, as for the time which immerses a base material (A) in a process liquid (1), 120 minutes or less are more preferable.

After the immersion, the obtained base material (A ′) may be washed, dried, and the like.
The drying conditions such as the drying temperature and the drying time depend on the type of material of the base material (A) for the polishing pad and thus cannot be determined unconditionally, and may be appropriately determined according to the material. It is preferable that the base material (A) for the polishing pad has a condition that does not cause deformation or alteration.

  The base material (A ′) produced as described above is obtained by adhering the base material (A) for the polishing pad and the compound (D). The conductive polymer (B) is more easily attached to the base material (A ′) by the compound (D).

[Conductive polymer having sulfonic acid group and / or carboxy group (B)]
The conductive polymer (B) used in the present invention has a sulfonic acid group and / or a carboxy group.
The conductive polymer (B) used in the present invention preferably has a volume resistivity of 1000 Ω · cm or less, and more preferably 500 Ω · cm or less.
The conductive polymer (B) may have a sulfonic acid group (—SO ₃ H) and a carboxy group (—COOH) in an ionic state (—SO ₃ ^— , —COO ⁻ ), respectively.

The amount of the sulfonic acid group and / or carboxy group that the conductive polymer (B) has is not particularly limited. Considering the conductivity, the proportion of the structural unit having a sulfonic acid group and / or a carboxy group in the conductive polymer (B) (hereinafter sometimes referred to as introduction ratio of the sulfonic acid group and / or carboxylic acid group). The amount is preferably 20 mol% or more, more preferably 70 mol% or more, based on all structural units constituting the conductive polymer (B). When the introduction ratio is 20 mol% or more, the solubility of the conductive polymer (B) in a solvent such as water becomes good. Therefore, the conductive polymer (B) can be easily attached to the substrate (A), and the resulting conductive polishing pad can exhibit sufficient conductivity.
The introduction ratio of the sulfonic acid group and / or carboxylic acid group can be adjusted, for example, by adjusting the ratio of the monomer having a sulfonic acid group and / or a carboxy group among all monomers used for the synthesis of the polymer. .
In addition, when a commercially available polymer is used as the conductive polymer (B), the introduction ratio can be confirmed by ion chromatography, neutralization titration or the like.

  As the conductive polymer (B), a polymer having at least one selected from the group consisting of structural units represented by the following formulas (1) to (3) is preferable.

［式（１）中、Ｒ^１〜Ｒ^２は、各々独立に、水素原子、−ＳＯ_３ ⁻、−ＳＯ_３Ｈ、−Ｒ^１１ＳＯ_３ ⁻、−Ｒ^１１ＳＯ_３Ｈ、−ＯＲ^１０、−Ｒ^１０、ハロゲン原子、−Ｎ（Ｒ^１２）_２、−ＮＨＣＯＲ^１２、−ＯＨ、−Ｏ⁻、−ＳＲ^１２、−ＯＲ^１２、−ＯＣＯＲ^１２、−ＮＯ_２、−ＣＯＯＨ、−Ｒ^１１ＣＯＯＨ、−ＣＯＯＲ^１２、−ＣＯＲ^１２、−ＣＨＯまたは−ＣＮであり、Ｒ^１０は、炭素数１〜２４のアルキル基であり、Ｒ^１１は、炭素数１〜２４のアルキレン基、炭素数１〜２４のアリーレンまたは炭素数１〜２４のアラルキレン基であり、Ｒ^１２は、炭素数１〜２４のアルキル基、炭素数１〜２４のアリール基または炭素数１〜２４のアラルキル基であり、Ｒ^１〜Ｒ^２のうち少なくとも一つは、−ＳＯ_３ ⁻、−ＳＯ_３Ｈ、−Ｒ^１１ＳＯ_３ ⁻、−Ｒ^１１ＳＯ_３Ｈ、−ＣＯＯＨまたは−Ｒ^１１ＣＯＯＨである。］

Wherein ^(1), R 1 ~R ² are each independently a hydrogen _{^{atom, -SO 3 -, -SO 3 H}} , -R 11 SO 3 -, -R 11 SO 3 H, -OR 10, - R ¹⁰ , halogen atom, —N (R ¹² ) ₂ , —NHCOR ¹² , —OH, —O ⁻ , —SR ¹² , —OR ¹² , —OCOR ¹² , —NO ₂ , —COOH, —R ¹¹ COOH, — COOR ¹² , —COR ¹² , —CHO or —CN, R ¹⁰ is an alkyl group having 1 to 24 carbon atoms, R ¹¹ is an alkylene group having 1 to 24 carbon atoms, arylene having 1 to 24 carbon atoms or an aralkylene group having 1 to 24 carbon ^{atoms, R 12} is an alkyl group, an aralkyl group an aryl group or a 1 to 24 carbon atoms having 1 to 24 carbon atoms having 1 to 24 carbon ^atoms, R 1 to R ² At least one of which is -S O ₃ ⁻ , —SO ₃ H, —R ¹¹ SO ₃ ^— , —R ¹¹ SO ₃ H, —COOH, or —R ¹¹ COOH. ]

［式（２）中、Ｒ^３〜Ｒ^６は、各々独立に、水素原子、−ＳＯ_３ ⁻、−ＳＯ_３Ｈ、−Ｒ^１１ＳＯ_３ ⁻、−Ｒ^１１ＳＯ_３Ｈ、−ＯＲ^１０、−Ｒ^１０、ハロゲン原子、−Ｎ（Ｒ^１２）_２、−ＮＨＣＯＲ^１２、−ＯＨ、−Ｏ⁻、−ＳＲ^１２、−ＯＲ^１２、−ＯＣＯＲ^１２、−ＮＯ_２、−ＣＯＯＨ、−Ｒ^１１ＣＯＯＨ、−ＣＯＯＲ^１２、−ＣＯＲ^１２、−ＣＨＯまたは−ＣＮであり、Ｒ^１０は、炭素数１〜２４のアルキル基であり、Ｒ^１１は、炭素数１〜２４のアルキレン基、炭素数１〜２４のアリーレンまたは炭素数１〜２４のアラルキレン基であり、Ｒ^１２は、炭素数１〜２４のアルキル基、炭素数１〜２４のアリール基または炭素数１〜２４のアラルキル基であり、Ｒ^３〜Ｒ^６のうち少なくとも一つは、−ＳＯ_３ ⁻、−ＳＯ_３Ｈ、−Ｒ^１１ＳＯ_３ ⁻、−Ｒ^１１ＳＯ_３Ｈ、−ＣＯＯＨまたは−Ｒ^１１ＣＯＯＨである。］

[In the formula (2), R ^{3 to} R ⁶ each independently represent a hydrogen atom, —SO ₃ ^— , —SO ₃ H, —R ¹¹ SO ₃ ^— , —R ¹¹ SO ₃ H, —OR ¹⁰ , — R ¹⁰ , halogen atom, —N (R ¹² ) ₂ , —NHCOR ¹² , —OH, —O ⁻ , —SR ¹² , —OR ¹² , —OCOR ¹² , —NO ₂ , —COOH, —R ¹¹ COOH, — COOR ¹² , —COR ¹² , —CHO or —CN, R ¹⁰ is an alkyl group having 1 to 24 carbon atoms, R ¹¹ is an alkylene group having 1 to 24 carbon atoms, arylene having 1 to 24 carbon atoms or an aralkylene group having 1 to 24 carbon ^{atoms, R 12} is an alkyl group, an aralkyl group an aryl group or a 1 to 24 carbon atoms having 1 to 24 carbon atoms having 1 to 24 carbon ^atoms, R 3 to R ⁶ At least one of which is -S O ₃ ⁻ , —SO ₃ H, —R ¹¹ SO ₃ ^— , —R ¹¹ SO ₃ H, —COOH, or —R ¹¹ COOH. ]

［式（３）中、Ｒ^７〜Ｒ^１０は、各々独立に、水素原子、−ＳＯ_３ ⁻、−ＳＯ_３Ｈ、−Ｒ^１１ＳＯ_３ ⁻、−Ｒ^１１ＳＯ_３Ｈ、−ＯＲ^１０、−Ｒ^１０、ハロゲン原子、−Ｎ（Ｒ^１２）_２、−ＮＨＣＯＲ^１２、−ＯＨ、−Ｏ⁻、−ＳＲ^１２、−ＯＲ^１２、−ＯＣＯＲ^１２、−ＮＯ_２、−ＣＯＯＨ、−Ｒ^１１ＣＯＯＨ、−ＣＯＯＲ^１２、−ＣＯＲ^１２、−ＣＨＯまたは−ＣＮであり、Ｒ^１０は、炭素数１〜２４のアルキル基であり、Ｒ^１１は、炭素数１〜２４のアルキレン基、炭素数１〜２４のアリーレンまたは炭素数１〜２４のアラルキレン基であり、Ｒ^１２は、炭素数１〜２４のアルキル基、炭素数１〜２４のアリール基または炭素数１〜２４のアラルキル基であり、Ｒ^７〜Ｒ^１０のうち少なくとも一つは、−ＳＯ_３ ⁻、−ＳＯ_３Ｈ、−Ｒ^１１ＳＯ_３ ⁻、−Ｒ^１１ＳＯ_３Ｈ、−ＣＯＯＨまたは−Ｒ^１１ＣＯＯＨである。］

[In the formula (3), R ^{7 to} R ¹⁰ are each independently a hydrogen atom, —SO ₃ ^— , —SO ₃ H, —R ¹¹ SO ₃ ^— , —R ¹¹ SO ₃ H, —OR ¹⁰ , — R ¹⁰ , halogen atom, —N (R ¹² ) ₂ , —NHCOR ¹² , —OH, —O ⁻ , —SR ¹² , —OR ¹² , —OCOR ¹² , —NO ₂ , —COOH, —R ¹¹ COOH, — COOR ¹² , —COR ¹² , —CHO or —CN, R ¹⁰ is an alkyl group having 1 to 24 carbon atoms, R ¹¹ is an alkylene group having 1 to 24 carbon atoms, arylene having 1 to 24 carbon atoms or an aralkylene group having 1 to 24 carbon ^{atoms, R 12} is an alkyl group, an aralkyl group an aryl group or a 1 to 24 carbon atoms having 1 to 24 carbon atoms having 1 to 24 carbon ^atoms, R 7 ^{to R 10} At least one of _{^{-SO 3 -, -SO 3 H,}} -R 11 SO 3 -, a -R 11 SO 3 H, -COOH or ^-R 11 COOH. ]

In formulas (1) to (3), R ¹⁰ is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and particularly preferably a methyl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In the conductive polymer (B), the proportion of the structural units represented by the formulas (1) to (3) is 20 to 100 mol with respect to all the structural units (100 mol%) constituting the conductive polymer (B). % Is preferred.
The conductive polymer (B) preferably has 10 or more repeating units represented by the formulas (1) to (3).
The conductive polymer (B) may have a structural unit other than the structural units represented by the formulas (1) to (3). The other structural unit is not particularly limited as long as it is derived from a monomer copolymerizable with a monomer that derives the structural unit represented by formulas (1) to (3).

The mass average molecular weight of the conductive polymer (B) is preferably 5,000 to 1,000,000, and more preferably 5,000 to 20,000. When the mass average molecular weight of the conductive polymer (B) is 5000 or more, the conductivity, film formability and film strength are excellent. If the mass average molecular weight of a conductive polymer (B) is 1 million or less, it is excellent in the solubility to a solvent.
Moreover, it is preferable that molecular weight distribution is 1-30, and, as for a conductive polymer (B), it is more preferable that it is 1-10. The molecular weight distribution is a value determined by (mass average molecular weight / number average molecular weight).
The mass average molecular weight and number average molecular weight of the conductive polymer (B) are measured by gel permeation chromatography (GPC) (in terms of polyethylene glycol).
The conductive polymer (B) may be synthesized by a conventionally known method, or may be appropriately selected from commercially available conductive polymers having a sulfonic acid group and / or a carboxy group.

[Conductive member (C)]
The conductive member (C) is obtained by attaching a conductive polymer (B) to the base material (A) or the base material (A ′) for the polishing pad.
In the conductive member (C), the adhesion amount of the conductive polymer (B) may be appropriately adjusted depending on a desired conductivity level or the like. Preferably it is 0.01-20 mass% with respect to a base material (A) or a base material (A '), and 0.05-20 mass% is more preferable. When the amount of the conductive polymer (B) is 0.01% by mass or more, the conductivity is sufficiently improved, and when it is 20% by mass or less, the flexibility of the conductive member (C) is improved.

For the conductive member (C), for example, a base (A) or a base (A ′) for a polishing pad is added to a liquid containing the conductive polymer (B) (hereinafter referred to as a treatment liquid (2)). It can be produced by dipping.
The treatment liquid (2) can be prepared by dissolving or dispersing the conductive polymer (B) in a solvent.
Examples of the solvent include water; a mixed solvent of water and an organic solvent soluble in water. Examples of the water-soluble organic solvent include the same ones as described above.
As the solvent of the treatment liquid (2), water or a mixed solvent of water and alcohols is preferable.

The amount of the treatment liquid (2) used is such that the amount of the conductive polymer (B) in the treatment liquid (2) is 0.1 per 100 parts by mass of the base material (A) or the base material (A ′) to be immersed. An amount of 01 parts by mass or more is preferable, an amount of 1 part by mass or more is more preferable, and an amount of 10 parts by mass or more is more preferable. When the amount of the compound (B) is 0.01 parts by mass or more, a sufficient amount of the conductive polymer (B) adheres to the substrate (A) or the substrate (A ′).
Moreover, the usage-amount of a process liquid (2) is the quantity of the conductive polymer (B) in the said process liquid (2) with respect to 100 mass parts of base materials (A) or base materials (A ') to immerse. The amount of 200 parts by mass or less is preferable, and the amount of 150 parts by mass or less is more preferable.
As for content of the conductive polymer (B) in a processing liquid (2), 0.01-20 mass% is preferable with respect to the total mass (100 mass%) of a processing liquid (2). By making content of a conductive polymer (B) into this range, the electroconductivity of a base material (A) or a base material (A ') can be improved efficiently.

The pH of the treatment liquid (2) is preferably 5.0 or less, more preferably 3.0 or less, and even more preferably 1.5 or less before immersing the substrate (A) or the substrate (A ′). When the pH of the treatment liquid (2) is 3.0 or less, the conductivity of the resulting conductive polishing pad is improved.
Examples of the method for adjusting the pH include a method of adding a compound exhibiting acidity in an aqueous solution. Examples of the compound include mineral acids such as sulfuric acid, hydrochloric acid and nitric acid; organic carboxylic acids such as acetic acid and formic acid; and organic sulfonic acids such as toluenesulfonic acid, dodecylbenzenesulfonic acid and methanesulfonic acid.
You may add the additive (for example, leveling agent, inorganic salt, etc.) used for dyeing | staining with an acidic dye to a process liquid (2) as needed.

Immersion may be performed at room temperature, or heat treatment may be performed simultaneously with the immersion. By performing the heat treatment, adhesion of the conductive polymer (B) to the substrate (A) or the substrate (A ′) can be accelerated.
The temperature of the treatment liquid (2), that is, the immersion temperature is preferably 30 ° C. or higher, more preferably 50 ° C. or higher, and further preferably 70 ° C. or higher. The water resistance of an electroconductive material improves that the temperature of a process liquid (2) is 30 degreeC or more. As the temperature is higher, elution of the conductive polymer from the obtained conductive polishing pad is suppressed, and the durability is improved.
Further, the temperature of the treatment liquid (2) is preferably 130 ° C. or lower, and more preferably 95 ° C. or lower. If the temperature of the liquid of a conductive polymer (B) is 130 degrees C or less, a deformation | transformation or a quality change of a base material (A) can be prevented.
The method for heating the treatment liquid (2) is not particularly limited, and a conventionally known method can be used.
The time (immersion time) for immersing the substrate (A) or the substrate (A ′) in the treatment liquid (2) is preferably 5 minutes or more, more preferably 10 minutes or more, and further preferably 60 minutes or more. Moreover, 300 minutes or less are preferable and, as for the time which immerses a base material (A) or a base material (A ') in a process liquid (2), 120 minutes or less are more preferable.

After the immersion, the obtained conductive member (C) may be washed and dried.
The drying conditions such as the drying temperature and the drying time depend on the type of material of the base material (A) for the polishing pad and thus cannot be determined unconditionally, and may be appropriately determined according to the material. It is preferable that the base material (A) for the polishing pad has a condition that does not cause deformation or alteration.
There is no restriction | limiting in the method of drying, A hot air dryer, a hotplate, a vacuum dryer etc. can be illustrated.
A preferable drying temperature is 40 to 180 ° C.

When the conductive member (C) is immersed in water, the conductive member (C) preferably has no eluate in water.
The presence or absence of an eluate in water can be easily confirmed by visually observing the degree of water coloring.

<Conductive polishing pad>
The conductive polishing pad of the present invention has the conductive member (C).
Although there is no restriction | limiting in content of an electroconductive member (C) in an electroconductive polishing pad, It is preferable that the ratio of an electroconductive member (C) is 50 mass% or more with respect to the gross mass of this electroconductive polishing pad. 70 mass% or more is more preferable, and 90 mass% is further more preferable. The upper limit of the ratio is not particularly limited, and may be 100% by mass.

The conductive polishing pad of the present invention may further contain various adhesion improvers, crosslinking agents, and binder polymers as necessary.
Examples of the adhesion improver include a silane coupling agent.
Examples of the crosslinking agent include epoxy compounds, isocyanates, melamines, carbodiimides, and diol compounds.
As the binder polymer, an acrylic resin, a polyester resin, a urethane resin, an epoxy resin emulsion, water or an organic solvent-soluble resin is used.
When the conductive polishing pad has these components, the conductive polishing pad is used together with the conductive polymer (B) in, for example, the treatment liquid (2) used when the conductive member (C) is manufactured. It can be obtained by containing the component.

  In the conductive polishing pad of the present invention, the base material (A) or the base material (A ′) for the polishing pad, with the conductive polymer (B) as a binder, other than the conductive polymer (B). The conductive compound (E) is preferably attached. Thereby, the electroconductivity of an electroconductive polishing pad can further be improved, without impairing the "physical property" of the base material (A) for polishing pads. Here, the “physical properties” of the base material (A) for the polishing pad are not impaired, when the degree of occurrence of wiring scratch during polishing is the case where the conductive polishing pad of the present invention is used and the conductive polishing of the present invention. This means that there is no difference when a pad is not used (when a conventional non-conductive polishing pad is used).

There is no restriction | limiting in particular as an electroconductive compound (E), What is necessary is just to select suitably from conventionally well-known electroconductive compounds within the range which does not impair the effect of this invention.
Examples of the conductive compound (E) suitable for the present invention include carbon nanotubes.

As a method for adhering the conductive compound (E) to the base material (A) for the polishing pad using the conductive polymer (B) as a binder, for example, a carbon nanotube will be described as an example. And a method having two.
(Step 1):
First, the carbon nanotube and the conductive polymer (B) are dispersed in a solvent such as water to obtain a dispersion.
As a result, the conductive polymer (B) is adsorbed on the carbon nanotubes, and the carbon nanotubes can be stably present in water by the surfactant effect of the conductive polymer (B). At this time, the carbon nanotubes are desirably crushed as small as possible. Carbon nanotubes are highly hydrophobic when used alone, and form aggregates in water. For example, carbon nanotubes can be formed by adding a “necessary amount” of a conductive polymer (B) to a carbon nanotube using a wet media mill or an ultrasonic emulsifier. By crushing the aggregates, an aqueous solution in which the carbon nanotubes are emulsified in nano size can be obtained. Thereby, the problem of wiring scratches, which is a concern when a conductive material is mixed with a physical liquid in a polishing pad base material, can be solved.
Here, the “necessary amount” of the conductive polymer (B) is an amount necessary for the crushed carbon nanotubes to be stably present in water in that state, and is appropriately determined.
The amount of carbon nanotubes is appropriately determined depending on the required conductivity level (the conductivity increases as the amount of carbon nanotubes increases).
(Process 2):
Next, the dispersion liquid of carbon nanotubes obtained in step 1 is handled in the same manner as the treatment liquid (2) described above, and a conductive member (C) is produced.

<Method for producing conductive polishing pad>
In the method for producing a conductive polishing pad of the present invention, the base material (A ′) for polishing pad is immersed in a liquid containing a compound (D) having two or more amino groups. Is immersed in a liquid containing the conductive polymer (B) to obtain a conductive member (C).

In the production method of the present invention, the step of obtaining the conductive member (C) can be specifically performed by, for example, the following steps (a) and (b).
Step (a): A step of immersing the base material (A) for the polishing pad in a liquid containing the compound (D) to obtain the base material (A ′).
Step (b): A step of immersing the substrate (A) or the substrate (A ′) for the polishing pad in a liquid containing the conductive polymer (B) to obtain the conductive member (C).

Step (a) can be carried out in the same manner as the method for producing the substrate (A ′) mentioned in the description of the substrate (A ′) of the conductive polishing pad of the present invention.
In addition, in the method for producing the conductive member (C) mentioned in the description of the conductive member (C) of the conductive polishing pad of the present invention, the step (b) ).
By the said process, the electroconductive member (C) which consists of a base material (A ') and the electroconductive polymer (B) which adhered to this base material (A') and has a sulfonic acid group and / or a carboxy group is obtained. It is done.

  The manufacturing method of this invention may have processes other than the process of obtaining the said electroconductive member (C). For example, when the raw material for the polishing pad base material is used as the base material for the polishing pad (A), the conductive polymer (B) is attached to the raw material by the method described above. Through the molding step, the conductive member (C) can be obtained.

According to the production method of the present invention, the conductive polymer (B) is adhered via the compound (D), so that the “physical properties” of the substrate (A) for the polishing pad are hardly impaired. A polishing pad can be obtained.
Moreover, according to this manufacturing method, since the base material (A) for polishing pads is only immersed in the liquid containing the compound (D) and then immersed in the liquid of the conductive polymer (B), Can be easily manufactured at low cost.

In addition to the manufacturing method described above, the polishing pad substrate (A) or the substrate (as a manufacturing method capable of manufacturing a conductive polishing pad with almost no loss of the “physical properties” of the polishing pad substrate (A) A production method having a step of attaching a conductive compound (E) other than the conductive polymer (B) to A ′) using the conductive polymer (B) as a binder.
The method is the “method for adhering the conductive compound (E) to the base material (A) for the polishing pad using the conductive polymer (B) as a binder mentioned in the description of the conductive polishing pad of the present invention. It can be carried out in the same manner as above.

The conductive polishing pad of the present invention can be used in the same manner as a conventionally known polishing pad in a CMP process of semiconductor manufacturing.
The following method is mentioned as an example of the grinding | polishing method using the electroconductive polishing pad of this invention.
(Method 1): A polishing (flattening) method in which the wafer is pressed against a polishing pad while supplying an abrasive slurry, and the surface of the wafer is polished (flattened).
(Method 2): While supplying the abrasive slurry or the electrolytic solution, the wafer is pressed against the polishing pad, and a voltage is applied between the wafer and the conductive polishing pad to perform the electrolytic action. Polishing (flattening) method for polishing (flattening) the substrate.
Method 1 is general CMP, and method 2 is so-called ECMP.
In these polishing methods, by using the conductive polishing pad of the present invention as the polishing pad, while achieving a wiring scratch reduction level equal to or higher than that in the case of using the current CMP polishing pad or conductive polishing pad. , CMP or ECMP can be performed.

EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not restrict | limited by these Examples.
Here, physical property measurement and evaluation methods are shown below.
(Surface resistance value)
After the polishing pad was dried at 70 ° C. for 10 minutes, a surface resistance value was measured by a two-probe method using Hiresta UP MCP-HT450 (manufactured by Dia Instruments).
(Volume resistance value)
After 0.1 parts by mass of the conductive polymer (B) is formed into a tablet by a tablet molding machine for infrared absorption spectrum measurement, Loresta GP MCP-T610 (manufactured by Dia Instruments Co., Ltd.) is used and a four-probe method is used. The volume resistance value was measured.
(Introduction ratio of sulfonic acid group and / or carboxylic acid group)
The introduction ratio of the sulfonic acid group was measured by adding the conductive polymer (B) in concentrated nitric acid and heating, and measuring the content of the sulfur element in the decomposition product by ion chromatography.
The introduction ratio of the carboxylic acid group was measured by neutralization titration.
(Measurement of molecular weight and molecular weight distribution)
The molecular weight distribution and molecular weight of the conductive polymer (B) were measured by GPC (polystyrene sulfonic acid equivalent) using a GPC column for an aqueous solution.
In the GPC, two columns for aqueous solutions (both “water-based GPC column PWX3000XL” manufactured by Tosoh Corporation) were connected and used. As an eluent, a 0.02 M lithium bromide solution in water / methanol = 7/3 (volume ratio) was used.

(CMP polishing test method (test conditions))
Non-processed product (wafer): A wafer obtained by forming (plating) a copper film having a thickness of 1.5 μm on a silicon substrate having a diameter of 8 inches.
CMP slurry: 30 g of hydrogen peroxide solution having a concentration of 30 wt% per 1 kg of Planerlite 7101 (Fujimi Incorporated).
Polishing apparatus: BC-15C (manufactured by MAT).
CMP slurry supply rate: 150 ml / min.
Head speed: 80 rpm.
Platen speed: 80 rpm.
Pressing pressure: 0.3 MPa.
* There is a movement of the head.

(Scratch property)
As a polishing pad, the conductive polishing pad manufactured in each of the examples and comparative examples, and as a control, a polishing pad IC-1000 (polyurethane system, diameter: 15 inches) manufactured by Nita Haas, which is a current CMP polishing pad, is used. Using the CMP polishing test, the wafer surface state on the side plated with copper was observed with an optical microscope (Microscope VH-7000, manufactured by Keyence Corporation), and micro scratches (fine scratches) were visually observed. Scratch) was evaluated according to the following criteria.
A: There is no difference in the number of micro scratches compared to the wafer surface state after using IC-1000.
○: The number of micro scratches is slightly increased compared to the wafer surface state after using IC-1000.
X: The number of micro scratches is greatly increased as compared with the wafer surface state after using IC-1000.

Moreover, in Examples 1-23 and Comparative Examples 1-3, the following were used as a base material (A) and a conductive polymer (B), respectively.
[Base material (A)]
-Substrate (A) -1: Polishing pad IC-1000 (polyurethane system, diameter: 15 inches) manufactured by Nitta Haas.
[Conductive polymer (B)]
Conductive polymer (B) -1: A polymer synthesized by the following procedure.
100 mol of 2-aminoanisole-4-sulfonic acid was dissolved in a 4 mol / L triethylamine aqueous solution at 25 ° C., and 100 mol of ammonium peroxodisulfate was added dropwise as an aqueous solution to the solution while stirring the solution. After completion of dropping, the mixture was further stirred at 25 ° C. for 12 hours. The reaction product was separated by filtration, washed, and dried to obtain 15 kg of a conductive polymer (B) -1 powder.
The volume resistance value of the conductive polymer (B) -1 is 9.0 Ω · cm, the introduction ratio of the sulfonic acid group is 100%, the number average molecular weight is 3,100, the mass average molecular weight is 18,000, and the molecular weight distribution is 6. there were.

Conductive polymer (B) -2: Espacer 100 (sulfonic acid group-containing soluble polythiophene derivative) manufactured by TA Chemical Co., Ltd.
The volume resistance value of the conductive polymer (B) -2 was 1 Ω · cm, the introduction ratio of sulfonic acid groups was 100%, the number average molecular weight was 5,000, the mass average molecular weight was 100,000, and the molecular weight distribution was 20. .

Conductive polymer (B) -3: manufactured by TA Chemical Co., Ltd., Espacer 300 (a sulfonic acid group-containing soluble polyisothianaphthene derivative).
The volume resistance value of the conductive polymer (B) -3 was 1 Ω · cm, the introduction ratio of sulfonic acid groups was 100%, the number average molecular weight was 12,300, the mass average molecular weight was 302,000, and the molecular weight distribution was 26. .

Conductive polymer (B) -4: A polymer synthesized by the following procedure.
100 mmol of 2-aminoanisole-4-carboxylic acid was dissolved in a 4 mol / L aqueous ammonia solution at 25 ° C. with stirring, and 100 mmol of ammonium peroxodisulfate was added dropwise to the solution as the solution was stirred. After completion of the dropwise addition, the mixture was further stirred at 25 ° C. for 12 hours, and then the reaction product was filtered off, washed and dried to obtain 10 g of a conductive polymer (B) -4 powder.
The volume resistance value of the conductive polymer (B) -4 was 100 Ω · cm, the introduction ratio of carboxy groups was 100%, the number average molecular weight was 2,100, the mass average molecular weight was 10,000, and the molecular weight distribution was 5.

Conductive polymer (B) -5: poly (2-sulfo-1,4-iminophenylene) synthesized according to “J. Chem. Soc., Chem. Commun., (1990), 180”).
The volume resistance value of the conductive polymer (B) -5 was 1000 Ω · cm, the introduction ratio of sulfonic acid groups was 33%, the number average molecular weight was 25,000, the mass average molecular weight was 90,000, and the molecular weight distribution was 4. .

Conductive polymer (B) -6: Polyaniline synthesized by a known method.
The volume resistance value of the conductive polymer (B) -6 was 0.1 Ω · cm, the introduction ratio of sulfonic acid groups was 0%, and the molecular weight could not be measured because polyaniline was not dissolved in an aqueous solvent.

<Production Examples 1 to 5: Production of conductive substrate (A ′)>
Substrate (A) -1 is immersed in the treatment liquid (1) having the composition shown in Table 1 under the immersion conditions shown in Table 1, and conductive substrates (A ′)-1 to (A ′)-5. Got.

<Examples 1 to 14, Comparative Example 1, Example 15>
In the treatment liquid (2) having the composition shown in Table 2, the conductive substrate (A ′) shown in Table 2 is immersed at the immersion temperature shown in Table 2 while being stirred for the immersion time shown in Table 2. It dried at 80 degreeC for 30 minute (s) in the hot air dryer, and the polishing pads 1-16 were obtained.
In addition, the usage-amount of the process liquid (2) was 2000 mass parts with respect to 100 mass parts of electroconductive base materials (A ') at this time.
About the obtained polishing pads 1-16, the surface resistance value (initial surface resistance value) was measured. The results are shown in Table 4.

<Examples 16 to 23>
In the treatment liquid (2) having the composition shown in Table 3, the substrate (A) -1 was immersed with stirring under immersion conditions of an immersion temperature of 20 to 25 ° C. (room temperature) and an immersion time of 1 hour. This was dried at the drying temperature and drying time shown in Table 3 to obtain polishing pads (C) -17 to (C) -24.
In addition, the usage-amount of the process liquid (2) was 2000 mass parts with respect to 100 mass parts of base material (A) -1 at this time.
The surface resistance value (initial surface resistance value) of the obtained polishing pads (C) -17 to (C) -24 was measured. The results are shown in Table 4.

<Comparative example 2>
A polishing pad 25 having a thickness of 2 mm was obtained by injection-molding 100 parts by mass of Elastollan S 90A (thermoplastic polyurethane elastomer, manufactured by BASF Polyurethane Elastomers) with 35 parts by mass of carbon black uniformly dispersed therein.
A surface resistance value (initial surface resistance value) of the polishing pad 25 was measured. The results are shown in Table 4.

  Each of the obtained polishing pads 1 to 25 was used to perform a polishing test by the CMP polishing test method. After the test, measurement of the surface resistance value (surface resistance value after the polishing test) of each polishing pad and evaluation of scratch properties Went. The results are shown in Table 4.

As is clear from the above results, the polishing pads of Examples 1 to 23 had a surface resistance value smaller than 1 × 10 ¹³ Ω both in the initial stage and after the polishing test, and it was confirmed that the polishing pads had good conductivity. Further, these polishing pads had little change in the surface resistance value before and after the polishing test, and had good scratch properties.
On the other hand, the polishing pad of Comparative Example 1 using a polymer having no sulfonic acid group and / or carboxyl group as the conductive polymer had a surface resistance value larger than 1 × 10 ¹³ Ω.
Further, the polishing pad of Comparative Example 2 made conductive by physically mixing the conductive material into the base material for the polishing pad has a low surface resistance, but the base material (A) which is the current CMP polishing pad The scratch property was worse than when -1 was used.

As described above in detail, the conductive polishing pad of the present invention greatly reduces wiring scratches compared to a polishing pad that is made conductive by physically mixing a conductive material into a base material for the polishing pad. Can be reduced.
Therefore, the conductive polishing pad of the present invention is not only useful as a polishing pad for CMP performed in a wiring formation process or the like in semiconductor manufacturing, but further, by applying current as necessary, ECMP ( It can also be used as a polishing pad for performing electrolytic polishing and CMP at the same time in a combined process of electrolytic polishing and CMP polishing.

Claims (4)

  A conductive polishing pad having a conductive member (C) formed by attaching a conductive polymer (B) having a sulfonic acid group and / or a carboxy group to a substrate (A) for a polishing pad.   A conductive polymer (B) having a sulfonic acid group and / or a carboxy group is formed on a substrate (A ′) formed by adhering a compound (D) having two or more amino groups to a substrate (A) for a polishing pad. A conductive polishing pad having a conductive member (C) attached thereto.   The proportion of the structural unit having a sulfonic acid group and / or a carboxy group in the conductive polymer (B) is 20 mol% or more with respect to all the structural units constituting the conductive polymer (B). 3. The conductive polishing pad according to 1 or 2.   A substrate (A) for polishing pad is immersed in a solution containing a compound (D) having two or more amino groups, and the obtained substrate (A ′) is a solution containing a conductive polymer (B). A method for producing a conductive polishing pad, comprising a step of obtaining a conductive member (C) by immersing in an aqueous solution.