JP2006100550A - Polishing solution material for metals, and polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing solution material for metals for manufacturing an LSI which has rapid CMP velocity, ensures uniformity on a wafer surface and generates less corrosion, scratch, thinning, dishing, erosion or the like. <P>SOLUTION: The polishing solution material is used for chemomechanical polishing in manufacturing a semiconductor device, and comprises an oxidant, an abrasive grain and a surfactant for absorption to the abrasive grain. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to the manufacture of a semiconductor device, and more particularly to a metal polishing liquid material and a polishing method using the same in a wiring process of a semiconductor device.

In the development of semiconductor devices typified by semiconductor integrated circuits (hereinafter referred to as LSIs), in order to achieve higher integration and higher speed, in recent years, higher density and higher integration have been demanded by miniaturization and lamination of wiring. . Chemical mechanical polishing (hereinafter referred to as CMP) has been used as a technique for this purpose. This is used for polishing an insulating thin film (such as SiO ₂ ) and a metal thin film used for wiring, and smoothes the substrate. This is a method of removing an excess metal thin film at the time of forming or wiring, and is disclosed in, for example, Patent Document 1.

A metal polishing solution used in CMP generally contains abrasive grains (for example, alumina) and an oxidizing agent (for example, hydrogen peroxide). The basic mechanism is considered to oxidize the metal surface with an oxidizing agent and remove the oxide film with abrasive grains, and is described in Non-Patent Document 1, for example.
However, when CMP is performed using a metal polishing liquid containing such solid abrasive grains, polishing scratches, a phenomenon in which the entire polishing surface is polished more than necessary (thinning), and the polishing metal surface on the plate In some cases, a phenomenon of bending (dishing), a phenomenon in which an insulator between metal wirings is polished more than necessary, and a metal surface of the wiring bends on a plate (erosion) may occur.
In addition, in a cleaning process usually performed to remove the polishing liquid remaining on the semiconductor surface after polishing, the cleaning process becomes complicated by using a polishing liquid containing solid abrasive grains. In order to treat (waste liquid), there is a problem in terms of cost, for example, it is necessary to settle and separate solid abrasive grains.

  As one means for solving these problems, for example, a metal surface polishing method using a combination of a polishing solution not containing abrasive grains and dry etching is disclosed in Non-Patent Document 2, and Patent Document 2 discloses hydrogen peroxide. Disclosed is a metal polishing fluid comprising: / malic acid / benzotriazole / ammonium polyacrylate and water. According to these methods, the metal film on the convex portion of the semiconductor substrate is selectively CMPed, and the metal film is left in the concave portion to obtain a desired conductor pattern. Since CMP proceeds by friction with a polishing pad that is much mechanically softer than that containing conventional solid abrasive grains, the occurrence of scratches is reduced.

  On the other hand, tungsten and aluminum have been widely used for interconnect structures as wiring metals. For example, Patent Document 3 and Patent Document 4 describe a polishing liquid and a method for polishing tungsten or aluminum. However, LSIs using copper, which has lower wiring resistance than these metals, have been developed with the aim of achieving higher performance. As a method of wiring this copper, for example, a damascene method described in Patent Document 5 is known. Further, a dual damascene method in which a contact hole and a wiring groove are simultaneously formed in an interlayer insulating film and a metal is embedded in both has been widely used. As a target material for copper wiring, a high-purity copper target of five nines or more has been shipped. However, in recent years, with the miniaturization of wiring aiming at further higher density, it has become necessary to improve the conductivity and electronic characteristics of copper wiring, and accordingly, a copper alloy in which a third component is added to high-purity copper is required. It is also beginning to be considered for use. At the same time, there is a need for high-speed metal polishing means that can exhibit high productivity without contaminating these high-definition and high-purity materials. These copper wirings are more likely to cause scratches called scratches than conventional aluminum wirings. On the other hand, there is a problem that the polishing rate does not increase because of the ductility.

Recently, in order to improve productivity, the diameter of a wafer at the time of manufacturing an LSI has been increased. Currently, a diameter of 200 mm or more is widely used, and manufacture of a diameter of 300 mm or more has started. With such an increase in size, the difference in polishing rate between the wafer central portion and the peripheral portion has increased, and the demand for improvement in in-plane uniformity has increased.
In addition, various abrasives are also introduced in Patent Documents 7 to 10 and the like. For example, Patent Document 8 discloses a metal polishing composition containing a compound that forms a polymer film on the surface of the metal film, and Patent Document 10 discloses. CMP polishing liquids containing abrasive grains with an amine or ammonium salt of a polycarboxylic acid type polymer are introduced. However, a product with sufficient performance has not been obtained.

US Pat. No. 4,944,836 JP 2001-127019 A JP 11-349926 A Japanese Patent Laid-Open No. 9-22887 JP-A-2-278822 JP-A-2-278822 JP 2004-134751 A JP 2004-153086 A JP 2004-179909 A Japanese Patent No. 3525824 Journal of Electrochemical Society, 138, 11 (1991), 3460-3464 Journal of Electrochemical Society; Volume 147, Issue 10 (2000), pages 3907-3913

  According to the present invention, in a CMP technique for flattening a metal, it is possible to realize a characteristic of selectively polishing a convex portion of a polishing surface in order to eliminate a step due to dishing and improve in-plane uniformity. A metal polishing aqueous solution is provided.

  As a result of intensive studies on the problems associated with the above-described metal polishing liquid, the present inventors have found that the problem can be solved by using the following metal polishing liquid, and have achieved the object. That is, the present invention is as follows.

(1) A metal-polishing liquid comprising an oxidizing agent, abrasive grains, and a compound adsorbed on the abrasive grains.

(2) The amount of adsorption of the compound adsorbed on the abrasive grains to the abrasive grains is 1.0 × ^{10 −30} to 1.0 × ^{10 −10} mol adsorbed per 1 nm ^{2 of the} abrasive grain surface area. The polishing liquid for metals of description.

(3) The abrasive grains and the compound adsorbed on the abrasive grains contain at least one of ester, ether, polysaccharide, amino acid salt, polycarboxylic acid, polycarboxylate, vinyl polymer, sulfonic acid, sulfonate, and amide. The metal-polishing liquid as described in (1) or (2) above.

(4) Further comprising at least one of a compound represented by the following general formula (I) and a compound represented by the general formula (I), any one of the above (1) to (3) The polishing liquid for metal as described.

In formula (I), R ₁ and R ₂ each independently represents a hydrogen atom or a substituent. R ₁ and R ₂ may be bonded to each other to form a ring. In addition, when R < ₁ > and R < ₂ > are hydrogen atoms simultaneously, the compound represented with general formula (I) may be the tautomer.
In formula (II), R _{3 to} R ₈ each independently represents a hydrogen atom or a substituent. Two adjacent ones of R _{3 to} R ₆ may be bonded to each other to form a ring. M ⁺ represents a cation.

(5) A chemical characterized in that the metal polishing liquid according to any one of the above (1) to (4) is brought into contact with the surface to be polished, and the surface to be polished and the polishing surface are moved relative to each other for polishing. Mechanical polishing method.

  With the metal polishing liquid of the present invention, the polishing speed depends on the polishing pressure, and it is possible to realize the characteristic of selectively polishing the convex part of the polishing surface where high pressure is applied during polishing, improving the uniformity in the wafer surface Is done.

Hereinafter, specific embodiments of the present invention will be described.
In addition, in the description of the group (atomic group) in this specification, the description which does not describe substitution and non-substitution includes what does not have a substituent and what has a substituent. . For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

The metal polishing liquid of the present invention (hereinafter also simply referred to as metal polishing liquid) contains at least an oxidizing agent, abrasive grains, and a compound that adsorbs to the abrasive grains as constituent components, and is usually an aqueous solution.
The metal polishing slurry of the present invention may further contain other components, and preferred surfactants and other water-soluble polymers, compounds represented by general formula (I) and (II) are preferred components. At least one of the compounds to be prepared, acid, chelating agent, alkaline agent / acid agent, and other additives.
Each component contained in the metal polishing slurry may be used alone or in combination of two or more.

In addition, among the components added when preparing the concentrate of the metal polishing liquid, the blending amount of water having a solubility in water at room temperature of less than 5% is to prevent precipitation when the concentrate is cooled to 5 ° C. The solubility in water at room temperature is preferably within 2 times, more preferably within 1.5 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 physical concentration operations such as evaporation are performed. It is used in a different way from the meaning of the general terms involved.

That is, 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 when used for polishing, water or an aqueous solution is used. It is diluted and used for polishing. The dilution factor is generally 1 to 20 volume times.
In the present invention, the “metal 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 metal polishing liquid.

  Hereinafter, each component will be described.

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

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

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

Among them, hydrogen peroxide, iodate, hypochlorite, chlorate, and an organic complex salt of iron (III) are preferable, and a preferable complex-forming compound in the case of using an organic complex salt of iron (III) is citric acid, Tartaric acid, aminopolycarboxylic acid (specifically, ethylenediamine-N, N, N ′, N′-tetraacetic acid, diethylenetriaminepentaacetic acid, 1,3-diaminopropane-N, N, N ′, N′-tetraacetic acid , Ethylenediamine-N, N′-disuccinic acid (racemic), ethylenediamine disuccinic acid (SS), N- (2-carboxylateethyl) -L-aspartic acid, N- (carboxymethyl) -L-aspartic acid , Β-alanine diacetate, methyliminodiacetic acid, nitrilotriacetic acid, iminodiacetic acid).
Among the oxidizing agents, hydrogen peroxide and iron (III) ethylenediamine-N, N, N ′, N′-tetraacetic acid, 1,3-diaminopropane-N, N, N ′, N′-tetraacetic acid and ethylenediaminedi A succinic acid (SS body) complex is most preferable.

  The addition amount of the oxidizing agent is preferably 0.003 mol to 8 mol, more preferably 0.03 mol to 6 mol, and more preferably 0.1 mol to 4 mol in 1 liter of the metal polishing liquid used for polishing. It is particularly preferable to do this. That is, the addition amount of the oxidizing agent is preferably 0.003 mol or more from the viewpoint of sufficient metal oxidation and ensuring a high CMP rate, and is preferably 8 mol or less from the viewpoint of preventing roughening of the polished surface.

[Abrasive grain]
The metal polishing liquid of the present invention contains abrasive grains. Examples of the abrasive grains include silica (precipitated silica, fumed silica, colloidal silica, synthetic silica), ceria, alumina, titania, zirconia, germania, manganese oxide, silicon carbide, polystyrene, polyacryl, polyterephthalate, and the like. .
The average grain size of the abrasive grains is preferably 5 to 1000 nm, particularly preferably 10 to 200 nm.
Of these abrasive grains, silica-based abrasive grains whose surface is negatively charged at a neutral pH range are more preferable, and colloidal silica is particularly preferable.

  As addition amount of an abrasive grain, it is preferable that an abrasive grain is 0.01-20 mass% with respect to the total mass of the polishing liquid for metals at the time of use, and is the range of 0.05-5 mass%. It is more preferable. In order to obtain a sufficient effect, the content is preferably 0.01% by mass or more, and since the polishing rate by CMP is saturated, 20% by mass or less is preferable.

[Compound adsorbed on abrasive grains]
The metal polishing slurry of the present invention contains a compound that adsorbs to abrasive grains. When the compound adsorbing to the abrasive grains is adsorbed to the abrasive grains, the degree of dependence of the polishing rate on the polishing pressure when using the polishing liquid is increased, and the characteristic of selectively polishing the convex portion of the polishing surface is obtained.

  The compounds that adsorb to the abrasive grains are usually surfactants, for example, anionic surfactants such as hexadecyltrimethylammonium chloride (HDMAC), lauryltrimethylammonium chloride, hexadecylpyridinium chloride, laurylpolydinium chloride, Nonionic surfactants such as polyoxyethylene distyrene phenyl ether are suitable.

The mode of adsorption between the compound adsorbed on the abrasive grains and the abrasive grains is not particularly limited, and examples include chemical adsorption, electrochemical adsorption, physical adsorption, etc., but the surface charge of the abrasive grains and the compound adsorbed on the abrasive grains The electrochemical adsorption utilizing the electric charge of is more preferable. The combination of the compound adsorbed to the abrasive grains and the pH environment, etc. are appropriately selected depending on the desired mode of adsorption, but in the present invention, in the state where the abrasive grain surface is positively charged, an anionic surface activity In the state where the surface of the agent and the abrasive grains is negatively charged, it is preferable to use a cationic surfactant. Specifically, it is usually preferable to combine silica abrasive grains whose surface is easily negatively charged with a cationic surfactant and use them in the pH range of 3 to 13, more preferably pH 6 to pH 11.
In particular, abrasive grains of colloidal silica, anionic surfactants such as hexadecyltrimethylammonium chloride (HDMAC), lauryltrimethylammonium chloride, hexadecylpyridinium chloride, laurylpolydinium chloride, and nonions such as polyoxyethylene distyrene phenyl ether It is preferable to use in combination with any of the surfactants.

In the present invention, the amount of the compound adsorbed to the abrasive grains adsorbs to the abrasive grains of 1.0 × ^{10 −30 to} 1.0 × ^{10 −10} mol per 1 nm ^{2 of} the abrasive surface area. preferable. Here, the amount of the compound adsorbed on the abrasive grains adsorbs on the abrasive grains is the concentration difference between CMC (CMC (w / abrasive)) when the abrasive grains are added and CMC (CMC (w / oabrasive)) when the abrasive grains are not added. It can be obtained from the following formula by measuring.
[CMC (w / abrasive) -CMC (w / o abrasive)]
Number of moles adsorbed = ----------------------------------------------
Abrasive grain concentration x surface area x adsorbed compound molecular weight (Mw)
More specifically, the adsorption amount of the compound adsorbed to the abrasive grains in the present invention to the abrasive grains is a value measured by the method described in Examples of the present application.
The total amount of the compound adsorbed to the abrasive grains is preferably 0.0001 to 10 g, more preferably 0.001 to 3 g in 1 L of the metal polishing liquid used for polishing. It is especially preferable to set it as 0.01-1g. That is, the amount of the compound adsorbed to the abrasive grains is preferably 0.0001 g or more for obtaining a sufficient effect, and preferably 10 g or less from the viewpoint of preventing the CMP rate from being lowered. Moreover, as a weight average molecular weight of the compound which adsorb | sucks to these abrasive grains, 50-100,000 are preferable, and 200-50000 are especially preferable.

[Other surfactants and / or hydrophilic polymers]
The metal polishing slurry of the present invention may contain other surfactant and / or hydrophilic polymer in addition to the surfactant as a compound adsorbed on the abrasive grains. Both the surfactant and the hydrophilic polymer have the action of reducing the contact angle of the surface to be polished and the action of promoting uniform polishing.
As other surfactants and / or hydrophilic polymers, the following can be used.
Examples of the anionic surfactant include carboxylate, sulfonate, sulfate ester salt and phosphate ester salt. As the carboxylate salt, soap, N-acyl amino acid salt, polyoxyethylene or polyoxypropylene alkyl ether carboxyl Acid salt, acylated peptide; as sulfonate, alkyl sulfonate, alkyl benzene and alkyl naphthalene sulfonate, naphthalene sulfonate, sulfosuccinate, α-olefin sulfonate, N-acyl sulfonate; sulfate ester Salts include sulfated oil, alkyl sulfates, alkyl ether sulfates, polyoxyethylene or polyoxypropylene alkyl allyl ether sulfates, alkyl amide sulfates; phosphate ester salts such as alkyl phosphates, polyoxyethylene or polyoxy B pyrene alkyl allyl ether phosphate can be exemplified.

As cationic surfactant, aliphatic amine salt, aliphatic quaternary ammonium salt, benzalkonium chloride salt, benzethonium chloride, pyridinium salt, imidazolinium salt; carboxybetaine type, aminocarboxylate as amphoteric surfactant And imidazolinium betaine, lecithin, and alkylamine oxide.
Nonionic surfactants include ether type, ether ester type, ester type and nitrogen-containing type. Ether type includes polyoxyethylene alkyl and alkylphenyl ether, alkylallyl formaldehyde condensed polyoxyethylene ether, polyoxyethylene poly Examples include oxypropylene block polymer, polyoxyethylene polyoxypropylene alkyl ether, ether ester type, glycerin ester polyoxyethylene ether, sorbitan ester polyoxyethylene ether, sorbitol ester polyoxyethylene ether, ester type, Polyethylene glycol fatty acid ester, glycerin ester, polyglycerin ester, sorbitan ester, propylene glycol ester Le, sucrose esters, nitrogen-containing type, fatty acid alkanolamides, polyoxyethylene fatty acid amides, polyoxyethylene alkyl amide, and the like.
Moreover, a fluorine-type surfactant etc. are mentioned.

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

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

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

  The total amount of other surfactants and / or hydrophilic polymers added is preferably 0.0001 to 10 g in 1 L of a metal polishing liquid used for polishing, and 0.001 to 3 g. More preferably, it is particularly preferably 0.01 to 1 g. That is, the addition amount of the surfactant and / or the hydrophilic polymer is preferably 0.0001 g or more for obtaining a sufficient effect, and is preferably 10 g or less from the viewpoint of preventing the CMP rate from being lowered. Moreover, as a weight average molecular weight of these surfactant and / or hydrophilic polymer, 50-100000 are preferable, and 200-50000 are especially preferable.

[Compound represented by general formula (I) and compound represented by general formula (II)]
The metal polishing slurry of the present invention preferably contains at least one of a compound represented by general formula (I) and a compound represented by general formula (II).

In formula (I), R ₁ and R ₂ each independently represents a hydrogen atom or a substituent. R ₁ and R ₂ may be bonded to each other to form a ring. In addition, when R < ₁ > and R < ₂ > are hydrogen atoms simultaneously, the compound represented with general formula (I) may be the tautomer.
In formula (II), R _{3 to} R ₈ each independently represents a hydrogen atom or a substituent. Two adjacent ones of R _{3 to} R ₆ may be bonded to each other to form a ring. M ⁺ represents a cation.

[Compound represented by formula (I)]

Although the substituent as R < ₁ > and R < ₂ > in Formula (I) is not specifically limited, For example, the following are mentioned.

  Halogen atom (fluorine atom, chlorine atom, bromine atom or iodine atom), alkyl group (straight chain, branched or cyclic alkyl group, and active methine group even if it is a polycyclic alkyl group such as a bicycloalkyl group) ), Alkenyl group, alkynyl group, aryl group, heterocyclic group (regarding the position of substitution), acyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, carbamoyl group (substituent) Examples of the carbamoyl group having an N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group), carbazoyl group, carboxy Group or a salt thereof, oxalyl group, oxamoy Group, cyano group, carbonimidoyl group (Carbonimidoyl group), formyl group, hydroxy group, alkoxy group (including groups containing ethyleneoxy group or propyleneoxy group unit), aryloxy group, heterocyclic oxy group, acyloxy group , (Alkoxy or aryloxy) carbonyloxy group, carbamoyloxy group, sulfonyloxy group, amino group, (alkyl, aryl, or heterocyclic) amino group, acylamino group, sulfonamido group, ureido group, thioureido group, N-hydroxy Ureido group, imide group, (alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (a Alkyl or aryl) sulfonylureido group, N-acylureido group, N-acylsulfamoylamino group, hydroxyamino group, nitro group, heterocyclic group containing a quaternized nitrogen atom (eg, pyridinio group, imidazolio group, quinolinio group) Group, isoquinolinio group), isocyano group, imino group, mercapto group, (alkyl, aryl, or heterocyclic) thio group, (alkyl, aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or Aryl) sulfinyl group, sulfo group or a salt thereof, sulfamoyl group (the sulfamoyl group having a substituent is, for example, an N-acylsulfamoyl group or an N-sulfonylsulfamoyl group) or a salt thereof, a phosphino group, a phosphinyl group, Phosphinyloxy group A sufinylamino group, a silyl group, etc. are mentioned.

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

  Among these, preferable substituents include, for example, halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, or iodine atoms), alkyl groups (straight chain, branched or cyclic alkyl groups, and polycyclic groups such as bicycloalkyl groups). An alkyl group or an active methine group), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (regarding the position of substitution), an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, hetero Ring oxycarbonyl group, carbamoyl group, N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group, carbazoyl group, oxalyl group, Oxamoyl group, cyano group, carboximide Group (Carbonimide group), formyl group, hydroxy group, alkoxy group (including groups containing ethyleneoxy group or propyleneoxy group unit), aryloxy group, heterocyclic oxy group, acyloxy group, (alkoxy or aryloxy) Carbonyloxy group, carbamoyloxy group, sulfonyloxy group, (alkyl, aryl, or heterocyclic) amino group, acylamino group, sulfonamide group, ureido group, thioureido group, N-hydroxyureido group, imide group, (alkoxy or aryl) Oxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfonylurei Group, N-acylureido group, N-acylsulfamoylamino group, hydroxyamino group, nitro group, quaternized heterocyclic group containing nitrogen atom (for example, pyridinio group, imidazolio group, quinolinio group, isoquinolinio group), Isocyano group, imino group, mercapto group, (alkyl, aryl, or heterocyclic) thio group, (alkyl, aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group Groups or salts thereof, sulfamoyl groups, N-acylsulfamoyl groups, N-sulfonylsulfamoyl groups or salts thereof, phosphino groups, phosphinyl groups, phosphinyloxy groups, phosphinylamino groups, silyl groups, etc. It is done. Here, the active methine group means a methine group substituted with two electron-withdrawing groups, and the electron-withdrawing group here means an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an alkyl group. Examples thereof include a sulfonyl group, an arylsulfonyl group, a sulfamoyl group, a trifluoromethyl group, a cyano group, a nitro group, and a carbonimidoyl group (Carbonimidoyl group).

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

The ring formed by combining R ₁ and R ₂ together with the —C—N— bond in formula (I) may be monocyclic or polycyclic, preferably a 5- to 6-membered ring. Or a polycyclic ring composed of a 5- to 6-membered ring.

  The above substituent may be further substituted with the above substituent.

  The molecular weight of the compound represented by the general formula (I) is preferably 20 to 600, more preferably 40 to 400.

  Specific examples of the compound represented by the general formula (I) are shown below, but are not limited thereto.

Among the compounds represented by the general formula (I), preferred are compounds I-1, I-3, I-4, I-10, I-15, I-21, I-22, I-23. , I-41 and I-48, and compounds I-1, I-4, I-15, I-22 and I-23 are more preferable. Particularly preferred is tetrazole of compound I-1.
Moreover, the compound represented by general formula (I) may be used independently, and may be used together 2 or more types.

  The compound represented by the general formula (I) can be synthesized according to a conventional method, or a commercially available product may be used.

The total amount of the compound represented by formula (I) is the metal polishing liquid used for polishing (that is, the metal polishing liquid after dilution when diluted with water or an aqueous solution. In 1 liter of “a metal polishing liquid for use in polishing”, 0.0001 to 1.0 mol is preferable, 0.001 to 0.5 mol is more preferable, and 0.01 to 0 is more preferable. .1 mol. That is, the addition amount of the compound represented by the general formula (I) is 1. in the metal polishing liquid 1L from the viewpoint of preventing deterioration (ineffective, decomposition) of the oxidant and the compound represented by the general formula (I). 0 mol or less is preferable, and 0.0001 mol or more is preferable for obtaining a sufficient effect.
A thiocyanate, a thioether, a thiosulfate, or a mesoionic compound may be used in combination in an amount smaller than the amount of the compound represented by the general formula (I).

[Compound represented by formula (II)]

(In formula, R < ₃ > -R < ₈ > represents a hydrogen atom or a substituent each independently. Two adjacent ones of R < ₃ > -R < ₆ > may couple | bond together and may form a ring. M ⁺ represents a cation.)

Although the substituent as R < ₃ > -R < ₈ > in Formula (II) is not specifically limited, For example, the following are mentioned.

  Halogen atom (fluorine atom, chlorine atom, bromine atom or iodine atom), alkyl group (straight chain, branched or cyclic alkyl group, and active methine group even if it is a polycyclic alkyl group such as a bicycloalkyl group) ), Alkenyl group, alkynyl group, aryl group, heterocyclic group (regarding the position of substitution), acyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, carbamoyl group (substituent) Examples of the carbamoyl group having an N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group), carbazoyl group, carboxy Group or a salt thereof, oxalyl group, oxamoy Group, cyano group, carbonimidoyl group (Carbonimidoyl group), formyl group, hydroxy group, alkoxy group (including groups containing ethyleneoxy group or propyleneoxy group unit), aryloxy group, heterocyclic oxy group, acyloxy group , (Alkoxy or aryloxy) carbonyloxy group, carbamoyloxy group, sulfonyloxy group, amino group, (alkyl, aryl, or heterocyclic) amino group, acylamino group, sulfonamido group, ureido group, thioureido group, N-hydroxy Ureido group, imide group, (alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (a Alkyl or aryl) sulfonylureido group, N-acylureido group, N-acylsulfamoylamino group, hydroxyamino group, nitro group, heterocyclic group containing a quaternized nitrogen atom (eg, pyridinio group, imidazolio group, quinolinio group) Group, isoquinolinio group), isocyano group, imino group, mercapto group, (alkyl, aryl, or heterocyclic) thio group, (alkyl, aryl, or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or Aryl) sulfinyl group, sulfo group or a salt thereof, sulfamoyl group (the sulfamoyl group having a substituent is, for example, an N-acylsulfamoyl group or an N-sulfonylsulfamoyl group) or a salt thereof, a phosphino group, a phosphinyl group, Phosphinyloxy group A sufinylamino group, a silyl group, etc. are mentioned.

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

  These substituents may be further substituted with these substituents.

Among these, as preferred substituents, at least one of R _{3 to} R ₆ is a substituent other than an alkyl group having no substituent, and more preferably, each of R _{7 to} R ₈ is a hydrogen atom. . Particularly preferably, at least one of R _{3 to} R ₆ is the above-described electron-withdrawing group, and each of R _{7 to} R ₈ is a hydrogen atom.

The cation as M ⁺ is not particularly limited. For example, hydrogen ion, alkali metal ion (eg, Na ⁺ , K ⁺ , Li ^+, etc.), ammonium ion (eg, NH ₄ ⁺ , quaternary ammonium ion, etc.) Can be mentioned.

  The molecular weight of the compound represented by the general formula (II) is preferably 20 to 600, more preferably 40 to 400.

Specific examples of the compound represented by the general formula (II) are shown below, but are not limited thereto.

  Among the above compounds, II-2, II-5, II-9, II-27, II-29, II-30, II-33, II-35 and II-37 are preferred, and II-5, II -9, II-27, II-29 and II-33 are particularly preferred.

Furthermore, examples include salts obtained by substituting the hydrogen atom of the carboxy group in the above exemplified compounds with alkali metal ions such as Na ⁺ , K ⁺ and Li ^+, and ammonium ions such as NH ₄ ⁺ and quaternary ammonium ions. .

  Moreover, the compound represented by general formula (II) may be used independently, and may be used together 2 or more types.

The compound represented by the general formula (II) may be a commercially available product or may be synthesized according to a conventional method.
For example, Compound II-29 can be synthesized according to the synthesis method described in Synthesis (8), 654-659 (1983). Compound II-37 can be synthesized according to the methods described in Tetrahedron Letters, 51 (7), 1861-1866 (1995) and Tetrahedron Letters, 44 (25), 4741-4745 (2003). Other compounds can also be synthesized according to the methods described therein.

The total amount of the compound represented by formula (II) is the metal polishing liquid used for polishing (that is, the metal polishing liquid after dilution when diluted with water or an aqueous solution. In 1 liter of “a metal polishing liquid for use in polishing”, 0.0001 to 1.0 mol is preferable, 0.001 to 0.5 mol is more preferable, and 0.01 to 0 is more preferable. .1 mol. That is, the addition amount of the compound represented by the general formula (II) is 1. in the metal polishing liquid 1L from the viewpoint of preventing deterioration (ineffective, decomposition) of the compound represented by the oxidizing agent and the general formula (II). 0 mol or less is preferable, and 0.0001 mol or more is preferable for obtaining a sufficient effect.
A thiocyanate, a thioether, a thiosulfate, or a mesoionic compound may be used in combination in an amount smaller than the amount of the compound represented by the general formula (II).

[acid]
The metal polishing slurry of the present invention preferably further contains an acid. The acid here is a compound having a structure different from that of the oxidizing agent for oxidizing the metal, and does not include an acid that functions as the above-mentioned oxidizing agent. The acid here has an action of promoting oxidation, adjusting pH, and buffering agent. Examples of acids include inorganic acids, organic acids, and amino acids in that range.
Examples of the inorganic acid include sulfuric acid, nitric acid, boric acid, phosphoric acid, etc. Among the inorganic acids, phosphoric acid is preferable.
In the present invention, organic acids and amino acids are particularly preferably present, and amino acids are more preferable.
The organic acid is preferably water-soluble. Those selected from the following group are more suitable. Formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid , N-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, Examples thereof include tartaric acid, citric acid, lactic acid, and salts thereof such as ammonium salt and alkali metal salt, sulfuric acid, nitric acid, ammonia, ammonium salts, or a mixture thereof. Among these, formic acid, malonic acid, malic acid, tartaric acid, and citric acid are suitable for a laminated film including at least one metal layer selected from copper, a copper alloy, and an oxide of copper or a copper alloy.

The amino acid is preferably water-soluble. Those selected from the following group are more suitable.
Glycine, L-alanine, β-alanine, L-2-aminobutyric acid, L-norvaline, L-valine, L-leucine, L-norleucine, L-isoleucine, L-alloisoleucine, L-phenylalanine, L-proline, Sarcosine, L-ornithine, L-lysine, taurine, L-serine, L-threonine, L-allothreonine, L-homoserine, L-tyrosine, 3,5-diodo-L-tyrosine, β- (3 4-dihydroxyphenyl) -L-alanine, L-thyroxine,

4-hydroxy-L-proline, L-cystine, L-methionine, L-ethionine, L-lanthionine, L-cystathionine, L-cystine, L-cysteic acid, L-aspartic acid, L-glutamic acid, S- (carboxy Methyl) -L-cysteine, 4-aminobutyric acid, L-asparagine, L-glutamine, azaserine, L-arginine, L-canavanine, L-citrulline, δ-hydroxy-L-lysine, creatine, L-quinurenin, L- Amino acids such as histidine, 1-methyl-L-histidine, 3-methyl-L-histidine, ergothioneine, L-tryptophan, actinomycin C1, apamin, angiotensin I, angiotensin II and antipine.
In particular, malic acid, tartaric acid, citric acid, glycine, and glycolic acid are preferable in that the etching rate can be effectively suppressed while maintaining a practical CMP rate.

  The amount of acid added is preferably 0.0005 to 0.5 mol, more preferably 0.005 mol to 0.3 mol, in 1 L of the metal polishing liquid used for polishing, and 0.01 mol. It is especially preferable to set it to -0.1 mol. That is, the amount of acid added is preferably 0.5 mol or less from the viewpoint of suppressing etching, and 0.0005 mol or more is preferable for obtaining a sufficient effect.

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

Two or more chelating agents may be used in combination as required.
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 in 1 L of a metal polishing liquid used for polishing. 0.07 mol is added.

[Alkaline agent]
The metal polishing slurry of the present invention may contain an alkali agent for pH adjustment, and further a buffer from the viewpoint of suppressing pH fluctuation.

  Alkaline agents (and buffering agents) include non-metallic alkaline agents such as organic ammonium hydroxides such as ammonium hydroxide and tetramethylammonium hydroxide, alkanolamines such as diethanolamine, triethanolamine and triisopropanolamine, Alkali metal hydroxide such as sodium hydroxide, potassium hydroxide, lithium hydroxide, carbonate, phosphate, borate, tetraborate, hydroxybenzoate, glycyl salt, N, N-dimethylglycine salt , Leucine salt, norleucine salt, guanine salt, 3,4-dihydroxyphenylalanine salt, alanine salt, aminobutyrate, 2-amino-2-methyl-1,3-propanediol salt, valine salt, proline salt, trishydroxyamino Use methane salt, lysine salt, etc. wear.

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

The addition amount of the alkaline agent 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 metal polishing liquid used for polishing. It is more preferable to set it as 003 mol-0.5 mol.
2-14 are preferable and, as for pH of the metal polishing liquid at the time of using for grinding | polishing, 3-12 are especially preferable. Within this range, the metal liquid of the present invention exhibits particularly excellent effects.

[Other additives]
Moreover, it is preferable to use the following additives for the metal polishing slurry of the present invention.
Ammonia; alkylamines such as dimethylamine, trimethylamine, triethylamine and propylenediamine; amines such as ethylenediaminetetraacetic acid (EDTA), sodium diethyldithiocarbamate and chitosan; dithizone, cuproin (2,2′-biquinoline), neocuproin (2, Imines such as 9-dimethyl-1,10-phenanthroline), bathocuproine (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and cuperazone (biscyclohexanone oxalylhydrazone); benzimidazole-2-thiol, 2- [2- (benzothiazolyl)] thiopropionic acid, 2- [2- (benzothiazolyl)] thiobutyric acid, 2-mercaptobenzothiazole, 1,2,
3-triazole, 1,2,4-triazole, 3-amino-1H-1,2,4-triazole, benzotriazole, 1-hydroxybenzotriazole, 1-dihydroxypropylbenzotriazole, 2,3-dicarboxypropylbenzo Triazole, 4-hydroxybenzotriazole, 4-carboxyl-1H-benzotriazole,

4-methoxycarbonyl-1H-benzotriazole, 4-butoxycarbonyl-1H-benzotriazole, 4-octyloxycarbonyl-1H-benzotriazole, 5-hexylbenzotriazole, N- (1,2,3-benzotriazolyl Azoles such as -1-methyl) -N- (1,2,4-triazolyl-1-methyl) -2-ethylhexylamine, tolyltriazole, naphthotriazole, bis [(1-benzotriazolyl) methyl] phosphonic acid ; Mercaptans such as nonyl mercaptan, dodecyl mercaptan, triazine thiol, triazine dithiol, triazine trithiol, and others, tetrazole, and quinaldic acid. Among these, chitosan, ethylenediaminetetraacetic acid, L-tryptophan, cuperazone, triazinedithiol, benzotriazole, 4-hydroxybenzotriazole, 4-carboxyl-1H-benzotriazole butyl ester, tolyltriazole, naphthotriazole have high CMP rate and low etching It is preferable for achieving both speeds.

  The addition amount of these additives is preferably 0.0001 mol to 0.5 mol, more preferably 0.001 mol to 0.2 mol, in 1 L of the metal polishing liquid used for polishing. It is especially preferable to set it as 005 mol-0.1 mol. That is, the addition amount of the additive is preferably 0.0001 mol or more from the viewpoint of suppressing etching, and preferably 0.5 mol or less from the viewpoint of preventing a decrease in CMP rate.

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

[Raw metal materials]
In the present invention, the semiconductor to be polished is preferably an LSI having wiring made of copper metal and / or copper alloy, and particularly preferably a copper alloy. Furthermore, the copper alloy containing silver is preferable among copper alloys. The silver content contained in the copper alloy is preferably 40% by mass or less, particularly preferably 10% by mass or less, more preferably 1% by mass or less, and most preferably in the range of 0.0001 to 0.1% by mass. Exhibits excellent effects.

[Wiring thickness]
In the present invention, the semiconductor to be polished is, for example, a DRAM device system having a half pitch of 0.15 μm or less, particularly 0.10 μm or less, more preferably 0.08 μm or less, while MPU device system is 0.12 μm or less. In particular, an LSI having wiring of 0.09 μm or less, more preferably 0.07 μm or less is preferable. The polishing liquid of the present invention exhibits particularly excellent effects on these LSIs.

[Barrier metal]
In the present invention, it is preferable to provide a barrier layer for preventing diffusion of wiring metal between the metal wiring and the interlayer insulating film. As the barrier layer, a low-resistance metal material is preferable, and TiN, TiW, Ta, TaN, W, and WN are particularly preferable, and Ta and TaN are particularly preferable.

[Polishing method]
The metal polishing liquid is a concentrated liquid, and when used, it is diluted with water to make a working liquid, or each component is mixed in the form of an aqueous solution described in the next section, and water is added if necessary. In some cases, it is used as a working solution after dilution. The polishing method using the metal polishing liquid of the present invention can be applied to any case, and the polishing liquid is supplied to a polishing surface or the like on a polishing surface plate and brought into contact with the surface to be polished to be polished. This is a polishing method in which polishing is carried out by relatively moving the particles.
As an apparatus for polishing, there is a general polishing apparatus having a polishing surface plate with a holder for holding a semiconductor substrate having a surface to be polished and a polishing pad attached (a motor etc. capable of changing the number of rotations is attached). Can be used. 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 substrate does not jump out. The pressure applied to the polishing pad of the semiconductor substrate having the surface to be polished (film to be polished) is preferably ⁵ to 500 g / cm ² in order to satisfy the uniformity of the polishing rate within the wafer surface and the flatness of the pattern. Is more preferably 12 to 300 g / cm ² .

  During polishing, a polishing liquid for metal is continuously supplied to the polishing pad with a pump or the like. Although there is no restriction | limiting in this supply amount, it is preferable that the surface of a polishing pad is always covered with polishing liquid. The semiconductor substrate after polishing is thoroughly washed in running water, and then dried after removing water droplets adhering to the semiconductor substrate using a spin dryer or the like. In the polishing method of the present invention, the aqueous solution to be diluted is the same as the aqueous solution described below. The aqueous solution is water that contains at least one of an oxidizing agent, an acid, an additive, and a surfactant in advance, and the total amount of the components contained in the aqueous solution and the components of the metal polishing liquid to be diluted is a metal. It becomes the component at the time of grinding | polishing using the polishing liquid. When diluted with an aqueous solution and used, components that are difficult to dissolve can be blended in the form of an aqueous solution, and a more concentrated metal polishing liquid can be prepared.

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

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

  As a method of diluting and polishing the concentrated metal polishing liquid with water or an aqueous solution, a pipe for supplying the metal polishing liquid and a pipe for supplying water or an aqueous solution are provided independently, and a predetermined amount of liquid is supplied from each. This is a method of polishing while supplying to the polishing pad and mixing by the relative movement of the polishing pad and the surface to be polished. Alternatively, there is a method in which a predetermined amount of concentrated metal polishing liquid and water or an aqueous solution are mixed in one container, and then the mixed metal polishing liquid is supplied to a polishing pad for polishing.

According to another polishing method of the present invention, a component to be contained in a metal polishing liquid is divided into at least two components, and when using them, a water or aqueous solution is added to dilute the polishing pad on a polishing platen. The surface to be polished is brought into contact with the surface to be polished, and the surface to be polished and the polishing pad are moved relative to each other for polishing.
For example, an oxidizing agent is one component (A), an acid, an additive, a surfactant, and water are one component (B), and when they are used, the component (A) The component (B) is diluted before use.
In addition, the low-solubility additive is divided into two components (A) and (B), and the oxidizing agent, additive and surfactant are one component (A), and the acid, additive, surfactant and Water is used as one component (B), and when these are used, water or an aqueous solution is added to dilute the component (A) and the component (B). In the case of this example, three pipes for supplying the component (A), the component (B), and water or an aqueous solution are required, and dilution mixing is performed on one pipe that supplies the three pads to the polishing pad. There is a method of combining and mixing in the pipe. In this case, it is also possible to combine two pipes and then connect another pipe.

For example, it is a method in which a component containing an additive that is difficult to dissolve is mixed with another component, a mixing path is lengthened to ensure a dissolution time, and then a pipe for water or an aqueous solution is further combined. Other mixing methods are as described above, in which the three pipes are each guided directly to the polishing pad and mixed by the relative movement of the polishing pad and the surface to be polished, and the three components are mixed in one container. A method for supplying a diluted metal polishing liquid to a polishing pad. In the above polishing method, one constituent component containing an oxidizing agent is made 40 ° C. or lower, the other constituent components are heated in the range of room temperature to 100 ° C., and one constituent component and another constituent component or water or an aqueous solution When the mixture is diluted and used, it can be adjusted to 40 ° C. or lower after mixing. Since the solubility increases when the temperature is high, this is a preferable method for increasing the solubility of the raw material having a low solubility in the metal polishing slurry.

  A raw material in which other components not containing an oxidizing agent are heated and dissolved in the range of room temperature to 100 ° C. is precipitated in the solution when the temperature is lowered. It is necessary to dissolve what is deposited by heating. For this, a means for feeding a heated component solution and a means for stirring the liquid containing the precipitate, feeding the liquid, and heating and dissolving the pipe can be employed. When the temperature of one component containing an oxidant is increased to 40 ° C. or higher, the oxidant may be decomposed. Therefore, the heated component and the oxidation for cooling the heated component When mixed with one component containing an agent, the temperature is set to 40 ° C. or lower.

  In the present invention, as described above, the component of the metal polishing liquid may be divided into two or more parts and supplied to the polishing surface. In this case, it is preferable to divide and supply the component containing an oxide and the component containing an acid. Alternatively, the metal polishing liquid may be a concentrated liquid, and the diluted water may be separately supplied to the polishing surface.

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

[Wafer]
The target wafer to be subjected to CMP with the metal polishing liquid of the present invention 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 polishing apparatus used in the process in which the polishing liquid of the present invention is used is not particularly limited. For example, Mirra Mesa CMP, Reflexion CMP (Applied Materials), FREX200, FREX300 (Ebara Corporation), NPS3301, NPS2301 (Nikon), A-FP-310A, A-FP-210A (Tokyo Seimitsu), 2300TERES (Ram Research), Momentum (SpeedfamIPEC), etc. can be mentioned.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to the following examples.

<Adsorption evaluation>
First, in order to investigate the adsorption of the compound adsorbed on the abrasive grains to the abrasive grains, the metal polishing liquid material having a concentration of hexadecyltrimethylammonium chloride (Mw: 319.3 or less HDMAC) and the HDMAC concentration were varied. A sample of a non-abrasive metal polishing liquid material was prepared and its surface tension was measured. Colloidal silica (surface area: 78 m ² / g (manufacturer value)) was used as the abrasive.
-Preparation of metal polishing liquid material First, 10 parts by mass of glycine as an acid (organic acid), 0.03 parts by mass of tetrazole as a protective film forming agent, and HDAMC designated amount were added to 600 parts by mass of water and dissolved. Solution A was obtained. Next, 256 parts by mass of colloidal silica PL-3 (19.5% aqueous solution) manufactured by Fuso Science Co., Ltd. was dissolved in Solution A to obtain Solution B. The solution B was adjusted to pH 7.2 using 25% aqueous ammonia, and pure water was added to make the total amount 1000 ml, whereby a metal polishing liquid material was obtained.
The surface tension was measured using a CBVP-Z type automatic surface tension meter manufactured by Kyowa Surfactant Science Co., Ltd. The measurement results are shown in FIG.

Since the samples showed different values of CMC (critical micelle concentration), it was confirmed that the compounds adsorbed on the abrasive grains were adsorbed on the abrasive grains. That is, the HDMAC adsorbed on the abrasive grains of 4.8 wt% was 0.12 wt% due to the difference in concentration between CMC (CMC (w / abrasive)) when the abrasive grains were added and CMC (CMC (w / oabrasive)) when the abrasive grains were not added. It was.
The amount of the compound adsorbed on the abrasive grains to the abrasive grains was determined by calculating the HDPC adsorption amount from the difference in CMC concentration determined by measurement.
[CMC (w / abrasive) -CMC (w / o abrasive)] / (Mw _HDMAC )
Number of moles adsorbed = ----------------------------------------------
From the calculation of abrasive concentration x surface area, it was confirmed that 1.35 x 10 ^-24 mol of HDPC molecules were adsorbed to 1 nm ^{2 of the} abrasive grain surface area.

  Next, for the purpose of comparison, an adsorption amount confirmation test was conducted in the same manner as in Example 1 except that laurylbetaine (hereinafter referred to as LB) was used instead of hexadecyltrimethylammonium chloride. It was confirmed that there was no difference in CMC concentration with and without abrasive grains, and there was no adsorption to abrasive grains.

<CMP performance evaluation>
Next, in order to evaluate the actual CMP characteristics, a trench having a depth of 5000 nm is formed in the insulating layer, a copper film is formed by a known sputtering method, and a silicon substrate embedded by a known heat treatment is used as a substrate. CMP was performed. The planarization characteristics of the substrate after CMP were examined. The level difference measurement was performed using Dektak V320-Si manufactured by Veeco.

The polishing conditions are as follows.
Polishing conditions The substrate to be polished was polished under the following polishing conditions by rotating the polishing pad and the substrate while supplying the metal polishing liquid to the polishing pad on the polishing surface plate in the polishing apparatus using a quantitative pump. . The polishing liquid was prepared in advance before polishing and held in one container (polishing liquid reservoir) and supplied to a metering pump unless otherwise specified. The polishing work was performed using BC-15 manufactured by MTT.

Base substrate Silicon substrate on which a copper film having a thickness of 1000 nm is formed Polishing pad: IC1400 (trade name, manufactured by Rodel) Polishing pressure: 1.2, 2.4, 3.6 (psi) Relative speed between the substrate and the polishing platen: 1.0 m / min
Polishing Product Evaluation Item Metal Polishing Liquid Flow Rate 50 ml / min Polishing Time: 60 sec. CMP Rate: The film thickness difference between before and after the CMP of the copper film was converted from the electrical resistance value. The film thickness difference measurement was performed using VR-120S manufactured by Kokusai Denki Alpha Co., Ltd.

Example 1
-Preparation of metal polishing liquid material First, 10 parts by mass of glycine, which is an acid (organic acid), 0.03 parts by mass of tetrazole, and a compound adsorbed on the abrasive grains shown in Table 1 were added to 600 parts by mass of water and dissolved. Thus, a solution A was obtained. Next, 256 parts by mass of colloidal silica PL-3 (19.5% aqueous solution) manufactured by Fuso Science Co., Ltd. was dissolved in Solution A to obtain Solution B. The solution B was adjusted to pH 7.2 using 25% aqueous ammonia, and pure water was added to make the total amount 1000 ml, whereby a metal polishing liquid material was obtained.
-Preparation of metal polishing liquid To the obtained metal polishing liquid material, 30 parts by mass of hydrogen peroxide solution (special grade, 30% aqueous solution) as an oxidizing agent was added to obtain a metal polishing liquid.

Polishing speed pressure dependency evaluation Using the obtained metal polishing liquid, the polishing pressure was 1.2, 2.4, 3.6 (psi), CMP was performed under the above polishing conditions, and the polishing speed was measured. .
-Dishing evaluation Using the obtained metal polishing liquid, polishing pressure is 1.2 psi, polishing time is [1000 (nm) x 60 / polishing rate (nm / min)] time (sec.), Etc. The CMP was performed under the above polishing conditions. The step of the polished wiring (line 100 μ, space 100 μ) portion was measured with a fine shape measuring device.

  Examples 2 and 3 and Comparative Examples 1 and 2 in which the compounds adsorbed on the abrasive grains were changed as shown in Table 1 were similarly evaluated. The results are shown in Table 1.

  As shown in Table 1, the polishing liquid containing the compound that adsorbs to the abrasive grains of the present invention has a polishing rate greatly dependent on the polishing pressure, and a remarkable improvement effect in the anti-dicing performance was recognized.

The graph which evaluates adsorptivity.

Claims (5)

  A metal-polishing liquid comprising an oxidizing agent, abrasive grains, and a compound that adsorbs to the abrasive grains. The metal polishing liquid material according to claim 1, wherein the amount of the surfactant adsorbed on the abrasive grains is 1.0 × ^{10 −30} to 1.0 × ^{10 −10} mol adsorbed per 1 nm ^{2 of the} abrasive grain surface area.   The compound adsorbed on the abrasive grains contains at least one of ester, ether, polysaccharide, amino acid salt, polycarboxylic acid, polycarboxylate, vinyl polymer, sulfonic acid, sulfonate, and amide. The metal polishing slurry according to 1 or 2. The metal polishing slurry according to any one of claims 1 to 3, further comprising at least one of a compound represented by the following general formula (I) and a compound represented by the general formula (II): .

In formula (I), R ₁ and R ₂ each independently represents a hydrogen atom or a substituent. R ₁ and R ₂ may be bonded to each other to form a ring. In addition, when R < ₁ > and R < ₂ > are hydrogen atoms simultaneously, the compound represented with general formula (I) may be the tautomer.
In formula (II), R _{3 to} R ₈ each independently represents a hydrogen atom or a substituent. Two adjacent ones of R _{3 to} R ₆ may be bonded to each other to form a ring. M ⁺ represents a cation.   5. A chemical mechanical polishing method comprising polishing the metal polishing liquid according to claim 1 in contact with the surface to be polished, and moving the surface to be polished and the polishing surface relative to each other.

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