JP2009182301A - Metal-polishing composition and chemical mechanical polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal-polishing composition and a chemical mechanical polishing method excellent in polishing speed, capable of preventing the occurrence of erosion by improving selectivity of copper/tantalum and copper/titanium during polishing performance, and grading up evenness. <P>SOLUTION: The metal-polishing composition contains a compound, a peroxo disulfate, and an abrasive grain. In formula (I) of the compound, R<SP>1</SP>represents a 3-12C alicyclic or aliphatic alkyl group without a substitutional group, or 3-12C alicyclic or aliphatic alkyl group with an amino group as the substitutional group, or 3-10C alicyclic or aliphatic alkyl group with a hydroxyl group as the substitutional group. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a metal polishing composition used when performing chemical mechanical planarization in a semiconductor device manufacturing process, and a polishing method using the same.

In the development of semiconductor devices typified by semiconductor integrated circuits (hereinafter sometimes referred to as “LSI”), in order to increase the integration and speed of semiconductor devices, wiring miniaturization and lamination methods are studied. Has been.
For this purpose, various techniques such as chemical mechanical polishing (hereinafter sometimes referred to as “CMP”) are employed. CMP is used to polish an interlayer insulating film (such as SiO ₂ ) or a metal thin film used for wiring to smooth the substrate or remove an excess metal thin film during wiring formation (for example, patents). Reference 1).

A general method of CMP is as follows.
A polishing pad is affixed on a circular polishing platen (platen), and the surface of the polishing pad is immersed in a polishing liquid. The surface of the substrate (wafer) is pressed against the polishing pad, and both the polishing surface plate and the substrate are rotated with a predetermined pressure (polishing pressure) applied from the back surface.
In CMP, the surface of the substrate is flattened by mechanical friction generated by the above operation.

  Conventionally, tungsten and aluminum have been widely used in interconnect structures as wiring metals. However, LSIs using copper, which has lower wiring resistance than these metals, have been developed with the aim of achieving higher performance. As a method for wiring this copper, a damascene method is known (for example, see Patent Document 2). Further, a dual damascene method in which a contact hole and a wiring 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 is shipped.

  However, in recent years, in order to miniaturize the wiring in accordance with the demand for higher density, improvements in the conductivity and electronic characteristics of the copper wiring are required. On the other hand, the use of a copper alloy obtained by adding a third component to high-purity copper has begun to be studied.

  There is also a need for high-speed metal polishing means that can increase productivity without contaminating these high-definition and high-purity materials. In particular, since copper is a soft metal, when polishing copper or copper alloys, only the center is polished deeper, resulting in dish-like depressions (dishing), or the surface of multiple wiring metal surfaces is a dish. A phenomenon (erosion) that forms a concave-shaped recess and a polishing flaw (scratch) are likely to occur, and an increasingly accurate polishing technique is required.

  In recent years, wafers have become larger in order to improve productivity. Currently, wafers with a diameter of 200 mm or more are widely used, and the manufacture of wafers with a diameter of 300 mm or more has started. As the size of the wafer increases, the difference in polishing rate between the central portion and the peripheral portion of the wafer tends to increase, and there is a strong demand for uniform polishing within the wafer surface.

On the other hand, as a chemical polishing method in which mechanical polishing means is not applied to copper and a copper alloy, a chemical polishing method based only on a dissolving action is disclosed (for example, see Patent Document 3).
However, in the chemical polishing method, since polishing is performed only by a chemical dissolution action, problems such as dishing of recesses, that is, dishing, are likely to occur compared to CMP in which the metal film of the protrusions is selectively chemically and mechanically polished. Flatness has become an issue.

In addition, when copper wiring is used in LSI manufacturing, a diffusion prevention layer called a barrier layer is generally provided between the wiring portion and the insulating layer in order to prevent copper ions from diffusing into the insulating material. The barrier layer is formed of a barrier material such as TaN, TaSiN, Ta, TiN, Ti, Nb, W, WN, Co, Zr, ZrN, Ru, CuTa alloy, MnSixOy, and MnOx, and is provided with one or more layers. .
Since these barrier materials have a conductive property, the barrier material on the insulating layer must be completely removed in order to prevent an error such as a leakage current. For this removal processing, a method similar to that for polishing the bulk of the metal wiring material can be applied. This is what is called barrier CMP.

  Further, in the bulk polishing of copper, dishing is likely to occur particularly in a wide metal wiring portion. Therefore, it is desirable that the amount of polishing and removal can be adjusted between the wiring portion and the barrier portion in order to be finally flattened. For this reason, it is desired that the polishing liquid for barrier polishing has an optimal polishing selectivity of copper / barrier metal. Further, since the wiring pitch and the wiring density are different in each level of the wiring layer, it is further desirable that the polishing selectivity can be adjusted as appropriate.

  The metal polishing composition used for CMP generally contains solid abrasive grains (eg, alumina, silica) and an oxidizing agent (eg, hydrogen peroxide, peroxodisulfate). The basic mechanism of CMP using such a metal polishing composition is considered to be that the metal surface is oxidized by an oxidizing agent and the oxide film is removed by abrasive grains (for example, polishing) (Refer nonpatent literature 1.).

A polishing agent containing peroxodisulfate has a feature that a high polishing rate can be obtained, but has a problem that dishing and erosion are likely to proceed. As one means for solving the dishing, benzotriazoles are used as an anticorrosive agent that suppresses polishing of a metal film (see, for example, Patent Document 4).
According to these methods, a protective film is formed on the metal film of the semiconductor substrate, and the metal film is left in the concave portion while the convex portion is removed by the abrasive grains, thereby obtaining a desired conductor pattern. Occurrence of dishing is suppressed by the protective film of the recess, and high flatness is obtained.

However, even when these anticorrosives that provide high flatness are used, the occurrence of erosion due to the corrosion of the barrier film cannot be suppressed, and further improvement has been demanded regarding the flatness required for manufacturing the device.
US Pat. No. 4,944,836 JP-A-2-278822 JP 49-122432 A JP-A-2005-116987 Journal of Electrochemical Society, 1991, Vol. 11, No. 11, pages 3460-3464 Journal of Electrochemical Society, 2000, Vol. 147, No. 10, pages 3907-3913

  An object of the present invention is to improve the polishing rate of a conductor film made of copper or copper metal, and to improve the polishing selectivity of copper / tantalum and copper / titanium in polishing, thereby suppressing the occurrence of erosion and flatness. An object of the present invention is to provide a metal-polishing composition having an improved surface roughness.

In view of the above situation, the present inventors have conducted extensive research and have solved the above problems by using a metal polishing composition in which an amine compound having a specific structure, peroxodisulfate, and abrasive grains are used in combination. As a result, the present invention has been found.
That is, the object of the present invention is achieved by the following means.

<1> A metal polishing composition used for chemical mechanical polishing of a conductor film mainly composed of copper or a copper alloy in a semiconductor device manufacturing process, wherein (a) a compound represented by the following general formula (I) And (b) peroxodisulfate, and (c) abrasive grains.

In general formula (I), R ¹ is an alicyclic or aliphatic alkyl group having no substituent having 3 to 12 carbon atoms, or an alicyclic or aliphatic group having 3 to 12 carbon atoms having an amino group as a substituent. Or an alicyclic or aliphatic alkyl group having 3 to 12 carbon atoms having a hydroxyl group as a substituent.

<2> R ¹ in the general formula (I) is a linear alkyl group having 6 to 7 carbon atoms, a branched alkyl group having 4 to 5 carbon atoms, or an alicyclic group having 6 to 7 carbon atoms. The metal polishing composition according to <1>, which is an alkyl group.
<3> The metal polishing composition according to <1> or <2>, wherein R ¹ in the general formula (I) is an alkyl group having 3 to 10 carbon atoms having a hydroxyl group as a substituent.

<4> The metal polishing composition according to any one of <1> to <3>, wherein the compound represented by the general formula (I) is a compound represented by the following general formula (II).

In general formula (II), R ² represents an aliphatic alkylene group having 4 to 12 carbon atoms or an alicyclic alkylene group having 4 to 12 carbon atoms.
<5> The metal polishing composition according to <4>, wherein R ² in the general formula (II) is an aliphatic alkylene group having 4 to 6 carbon atoms.

<6> The metal polishing composition according to any one of <1> to <5>, further comprising a compound represented by the following general formula (III).

In general formula (III), R ³ represents a hydrogen atom or an optionally substituted alkyl group, R ⁴ represents a hydrogen atom, an alkyl group, an aryl group, an acyl group, a carbamoyl group, a carboxy group, or a hydroxy group, Further, it may have a substituent, and examples of the substituent that can be introduced include an alkyl group, a phenyl group, a hydroxy group, a carboxyl group, a sulfo group, a carbamoyl group, an amide group, an amino group, and an alkoxy group.

<7> The metal polishing composition according to any one of <1> to <6> is supplied to a polishing pad on a polishing plate, and the polishing pad is rotated to polish the polishing pad. A chemical mechanical polishing method comprising polishing by relative movement while contacting a surface to be polished of a body.

According to the present invention, the conductor film made of copper or copper metal is excellent in the polishing rate, and the selectivity of copper / tantalum and copper / titanium in polishing is improved, thereby suppressing the occurrence of erosion and the flatness. An improved metal polishing composition can be provided.
In addition, it is excellent in the polishing rate of the conductor film made of copper or copper metal, and is improved in the selectivity of copper / tantalum and copper / titanium in polishing, thereby suppressing the occurrence of erosion and improving the flatness. A mechanical polishing method can be provided.

[Metal polishing composition]
The metal polishing composition of the present invention is a metal polishing composition used for chemical mechanical polishing of a conductor film mainly composed of copper or a copper alloy in a semiconductor device manufacturing process, and comprises (a) a general formula (I ), (B) peroxodisulfate, and (c) abrasive grains.
Moreover, you may contain another component as needed.
The metal polishing composition of the present invention usually takes the form of a slurry obtained by dispersing (c) abrasive grains in an aqueous solution obtained by dissolving each component.
The metal polishing composition of the present invention is useful for chemical mechanical polishing of an object to be polished having a conductor film made of copper or a copper alloy in a semiconductor device manufacturing process.

  The metal polishing composition of the present invention uses (a) an amine compound represented by the general formula (I), and (b) a peroxodisulfate salt and (c) an abrasive grain in combination. The polishing rate of the barrier film can be reduced without reducing the polishing rate of the conductor film made of an alloy. Although this reason is not clear, it is considered that the amine compound represented by the general formula (I) is selectively adsorbed on the barrier film and suppresses polishing by the metal polishing composition. For this reason, the metal polishing composition of the present invention is excellent in the polishing rate of a conductor film made of copper or copper metal, and in particular, the generation of erosion is improved by improving the selectivity of copper / tantalum and copper / titanium in polishing This also has the effect that it can be suppressed. Furthermore, the flatness is also improved.

  Although each component which comprises the metal polishing composition of this invention is explained in full detail below, each component may use only 1 type and may use 2 or more types together.

  In the present invention, the metal polishing composition (hereinafter, also simply referred to as “polishing composition”) is used not only in the composition (concentration) used for polishing but also diluted as necessary during use. The aspect is also referred to as a metal polishing composition in the present invention unless otherwise specified. When the concentrated liquid is used for polishing, it is diluted with water or an aqueous solution and used for polishing, and the dilution ratio is generally 1 to 20 times by volume.

<(A) Compound represented by formula (I)>
The metal polishing composition of the present invention contains (a) a compound represented by the following general formula (I).

In general formula (I), R ¹ is an alicyclic or aliphatic alkyl group having no substituent having 3 to 12 carbon atoms, or an alicyclic or aliphatic group having 3 to 12 carbon atoms having an amino group as a substituent. An alicyclic or aliphatic alkyl group having 3 to 10 carbon atoms having an alkyl group or a hydroxyl group as a substituent is represented.
In addition, when R ¹ is a substituted alkyl group, examples of the introduced substituent include an alkyl group having 1 to 6 carbon atoms, an aryl group, and a hydroxyl group. When the carbon number of R ¹ is smaller than 3, handling becomes difficult due to evaporation or the like, and when it is larger than 12, the solubility in a solvent is decreased, which is not preferable.

  Preferred compounds of general formula (I) include hexylamine, heptylamine, isoamylamine, 1-methylbutylamine, 1-ethylpropylamine, 2-methylbutylamine, tert-amylamine, 1,2-dimethylpropylamine, 1, 4-diaminobutane, 1,2-diamino-2-methylpropane, diaminopentane, 1,5-diamino-2-methylpentane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,12-diaminododecane, ethylenediamine, DL-1-amino-2-propanol, 4-amino-1-butanol, 2-amino-1-butanol, 2-amino-2-methyl- 1-propanol, 5-amino-1-pentanol, DL-2-amino- -Pentanol, 2-amino-3-methyl-1-butanol, 6-amino-3-methyl-1-butanol, 6-amino-1-hexanol, DL-2-amino-1-hexanol, etc. it can. More preferably, hexylamine, heptylamine, isoamylamine, sec-butylamine, 1,4-diaminobutane, 1,5-diamino-2-methylpentane, DL-1-amino-2-propanol, 2-amino-1- Butanol, 2-amino-2-methyl-1-propanol, and the like.

In the general formula (I), when R ¹ is an alkyl group having an amino group as a substituent, the compound represented by the general formula (I) is an aminoalkylamine. Compounds represented by II) are preferred.

In the general formula (II), R ² represents an alicyclic or aliphatic alkylene group having 4 to 12 carbon atoms. Preferably, it has 4 to 6 carbon atoms, and specific examples thereof include a butylene group, a pentylene group, a hexylene group, a cyclopentylene group, and a cyclohexylene group. Moreover, you may have a substituent and specifically, an alkyl group, an aryl group, a hydroxyl group, a carboxyl group, an aminoalkyl group, an alicyclic alkyl group etc. can be mentioned. Among these, a hydroxylalkyl group, an aminoalkyl group, and an alicyclic alkyl group are more preferable. When the number of carbon atoms is in the range of 4 to 12, complex formation with copper is facilitated, which is preferable.

(A) The addition amount of the compound represented by the general formula (I) or the general formula (II) is based on the total amount of the polishing composition used for polishing from the viewpoint of sufficiently high CMP rate and erosion suppression. The content is preferably 0.1% by mass or more and 5.0% by mass or less, and more preferably 0.5% by mass or more and 2.0% by mass or less.
In the range of this content, both the polishing rate and erosion become favorable, which is preferable.

<(B) Peroxodisulfate>
Next, peroxydisulfate will be described.
The polishing composition of the present invention contains (b) peroxodisulfate as a compound (oxidant) capable of oxidizing a metal (copper or copper alloy) to be polished.
Among the peroxodisulfates, ammonium peroxodisulfate or potassium peroxodisulfate is preferable, and ammonium peroxodisulfate is most preferable.

  (B) The amount of peroxodisulfate added is preferably 0.003 mol to 0.5 mol, and preferably 0.03 mol to 0.2 mol, per liter of the polishing composition when used for polishing. More preferably, 0.03 mol to 0.1 mol is particularly preferable. That is, the amount of (b) peroxodisulfate added is preferably 0.003 mol or more from the viewpoint of sufficient metal oxidation and ensuring a high CMP rate, and 0.5 mol or less from the viewpoint of preventing roughening of the polished surface.

<(C) Abrasive grains>
The polishing composition of the present invention contains (c) abrasive grains, and the abrasive grains have an action of accelerating the CMP rate.
Preferable abrasive grains include, for example, silica (silicon oxide), ceria, alumina, titania, zirconia, germania, manganese oxide and the like, and silica (precipitated silica, fumed silica, colloidal silica, synthetic silica) is particularly preferable. Colloidal silica is more preferable.
As a method for producing colloidal silica particles that can be preferably used as abrasive grains, for example, Si (OC ₂ H ₅ ) ₄ , Si (sec-OC ₄ H ₉ ) ₄ , Si (OCH ₃ ) ₄ , Si (OC ₄ H ₉ ) _{And a} method of hydrolyzing a silicon alkoxide compound such as ₄ by a sol-gel method. The colloidal particles thus obtained have a very sharp particle size distribution.

  The primary particle size of the abrasive grains is a particle size cumulative curve showing the relationship between the particle size of the abrasive grains and the cumulative frequency obtained by integrating the number of particles having the particle size, and the cumulative frequency of this curve is the point at which the cumulative frequency is 50%. It means the particle diameter. For example, LB-500 manufactured by HORIBA, Ltd. is used as a measuring device for obtaining the particle size distribution.

  When the abrasive grains are spherical, the values measured as they are can be adopted. However, the particle size of the amorphous particles is expressed by the diameter of a sphere that is equal to the particle volume. The particle size can be measured by various known methods such as photon correlation method, laser diffraction method, Coulter counter method, etc. In the present invention, observation with a scanning microscope or transmission electron micrograph with a replica method is possible. Is used to obtain and calculate the shape and size of each particle.

  Specifically, the particle thickness is obtained from the projected area of the particle and the shadow of the replica with reference to a diffraction grating of a known length, and the volume of each particle is calculated from these. In this case, although it depends on the particle size distribution, it is desirable to measure and statistically measure 500 or more particles. This method is described in detail in paragraph No. [0024] of JP-A-2001-75222, and the description can be applied to the present invention.

  The average particle size (primary particle size) of (c) abrasive grains contained in the polishing composition of the present invention is preferably in the range of 20 to 70 nm, more preferably 20 to 50 nm. Particles of 20 nm or more are preferred for the purpose of achieving a sufficient polishing speed. The particle size is preferably 70 nm or less for the purpose of preventing excessive frictional heat during polishing.

  In addition, not only the general inorganic abrasive grains as described above but also organic polymer particles can be used in combination as long as the effects of the present invention are not impaired. In addition, colloidal silica surface-modified with aluminate ions or borate ions, colloidal silica with controlled surface potential, such as colloidal silica with various surface treatments, composite abrasive grains composed of multiple materials, etc. It is also possible to use it accordingly.

  The amount of (c) abrasive grains added in the present invention is appropriately selected according to the purpose, but in general, it can be used in the range of 0.001 to 20 mass% with respect to the total mass of the metal polishing composition. However, in the present invention, due to the effects of the addition of the components (a) and (b), excellent polishing characteristics can be exhibited even when the amount of abrasive grains added is less than 1.0% by mass. From the viewpoint of suppressing scratches and the like, the amount of abrasive grains added is preferably less than 1.0% by mass, and more preferably in the range of 0.01 to 0.5% by mass.

  The polishing composition of the present invention may contain the following components as necessary in addition to the above-described components. Hereinafter, optional components applicable to the polishing composition of the present invention will be described.

<(D) Organic acid and inorganic acid>
The metal polishing composition according to the present invention preferably further contains (d) one or more compounds selected from the group consisting of organic acids and inorganic acids. These acids are not metal oxidizers, but have the effect of promoting oxidation, adjusting pH, and buffering agents.
Examples of the inorganic acid include sulfuric acid, nitric acid, boric acid, phosphoric acid, and carbonic acid.

The organic acid is preferably water-soluble. In particular, those selected from the following group are more suitable.
That is, 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-methyl Hexanoic 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, apple Acid, tartaric acid, citric acid, lactic acid, hydroxyethyliminodiacetic acid, iminodiacetic acid, acedamidoiminodiacetic acid, nitrilotripropanoic acid, nitrilotrimethylphosphonic acid, dihydroxyethylglycine, tricine, and their ammonium salts and alkali metals Examples thereof include salts such as salts, ammonium salts, and mixtures thereof.

An amino acid is also preferably used as one of the organic acids. The amino acid is preferably water-soluble. In particular, those selected from the following group are more suitable.
That is, 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-diiodo-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- (carboxymethyl) -L-cysteine, 4-aminobutyric acid Acid, L-asparagine, L-glutamine, azaserine, L-arginine, L-canavanine, L-citrulline, δ-hydroxy-L-lysine, creatine, L-kynurenine, L-histidine, 1-methyl-L-histidine, Examples include 3-methyl-L-histidine, ergothioneine, L-tryptophan, actinomycin C1, apamin, angiotensin I, angiotensin II, and antipine.

In the present invention, the following organic acids are particularly desirable from the standpoint of sufficiently high CMP rate and dishing suppression.
Glycine, iminodiacetic acid, methyliminodiacetic acid, N-methylglycine, nitrilotripropanoic acid, hydroxyethyliminodiacetic acid, L-alanine, β-alanine, glycylglycine, dihydroxyethylglycine, acetamidoiminodiacetic acid, tricine Etc.

  (D) The amount of the organic acid or inorganic acid added is preferably 0.005 to 0.5 mol, preferably 0.01 to 0.3 mol, in 1 L of the metal polishing composition used for polishing. Is more preferable, and 0.05 to 0.3 mol is particularly preferable. That is, the organic acid or inorganic acid is preferably 0.005 mol or more from the viewpoint of improving the polishing rate, and preferably 0.5 mol or less from the viewpoint of not worsening dishing.

In the metal polishing composition of the present invention, the organic acid or inorganic acid may be used alone or in combination of two or more.
These organic acids can be synthesized according to a conventional method, or commercially available products may be used.

<(E) Surfactant and / or (f) Hydrophilic polymer>
The polishing composition of the present invention can contain (e) a surfactant and / or (f) a hydrophilic polymer.
Both the surfactant and the hydrophilic polymer have the action of reducing the contact angle to the surface to be polished and the action of promoting uniform polishing.

The surfactant that can be used in the present invention is selected from the group of anionic (anionic), cationic (cationic), nonionic (nonionic), and amphoteric (betaine) surfactants. Are preferred.
Examples of the anionic surfactant include carboxylic acid, sulfonic acid, sulfate ester, phosphate ester and salts thereof.
Carboxylic acids and salts thereof include fatty acid salts (for example, beef tallow fatty acid soda, sodium stearate, potassium oleate, castor oil potash), N-acyl amino acid salts (for example, palm oil fatty acid sarcosine triethanolamine), polyoxyethylene Or a polyoxypropylene alkyl ether carboxylate and an acylated peptide are mentioned.

  Examples of sulfonic acids and salts thereof include alkyl sulfonates (for example, dioctyl sulfosuccinate ester salts), alkyl benzene sulfonic acids (for example, dodecyl benzene sulfonic acid (soft), (hard), ammonium dodecyl benzene sulfonate (soft), ( Hard), dodecylbenzenesulfonic acid triethanolamine), alkyl diphenyl ether disulfonate (eg, sodium alkyldiphenyl ether disulfonate), alkyl naphthalene sulfonate (eg, monoisopropyl naphthalene sulfonic acid, diisopropyl naphthalene sulfonic acid, triisopropyl naphthalene sulfone) Acid ammonium), alkylsulfosuccinates (eg sodium dialkylsulfosuccinate, polyoxyethylene lauryl ether) Disodium sulfosuccinate), α-olefin sulfonates, N-acyl sulfonates (for example, coconut oil fatty acid methyl taurine sodium, polyoxyethylene coconut oil aliphatic monoethanolamide sodium sulfate), naphthalene and other aromatic sulfonic acids Formalin condensates (for example, sodium salt of β-naphthalenesulfonic acid formalin condensate, sodium salt of special aromatic sulfonic acid formalin condensate).

Sulfated ester salts such as sulfated oils, alkyl sulfates (for example, sodium lauryl sulfate, higher alcohol sodium sulfate, triethanolamine lauryl sulfate, ammonium lauryl sulfate), alkyl ether sulfates (for example, polyoxyethylene or polyoxypropylene alkyl ether) Examples thereof include sulfates (for example, sodium polyoxyethylene lauryl sulfate, polyoxyethylene lauryl ether sulfate triethanolamine) and alkylamide sulfates.
As phosphate ester salts, alkyl phosphates (eg, potassium octyl phosphate, potassium lauryl phosphate, potassium octyl ether phosphate), polyoxyethylene or polyoxypropylene alkylallyl ether phosphates (eg, polyoxyethylene alkylphenyl ether phosphate) Acid).

Nonionic surfactants include ether type, ether ester type, ester type, and nitrogen-containing type.
The ether type includes polyoxyalkylene alkyl and polyoxyalkylene alkyl phenyl ether (for example, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene higher alcohol ether, Polyoxyethylene myristel ether, polyoxyethylene octyldodecyl ether), polyoxyethylene derivatives (eg, polyoxyethylene disulfonated phenyl ether), polyoxyethylene polyoxypropylene glycol, alkylallyl formaldehyde condensed polyoxyethylene ether, polyoxy Ethylene polyoxypropylene block polymer, polyoxyethylene polyoxypropylene Ruki ether, and the like.

  Ether ester types include glycerin ester polyoxyethylene ether, polyoxyethylene fatty acid ester (eg, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol distearate, polyoxyethylene hydrogenated castor oil), polyoxy Ethylene sorbitan fatty acid ester (for example, polyoxyethylene sorbitan monococonut oil fatty acid ester, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene Oxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sol Tan triisostearate, polyoxyethylene sorbitan mono coconut fatty acid ester, polyoxyethylene sorbit tetraoleate), include polyoxyethylene ethers of sorbitol esters.

Examples of the ester type include sorbitan fatty acid esters (for example, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan sesquioleate), glycerin fatty acid ester ( Examples thereof include glycerol monostearate and glycerol monooleate), polyglycerol ester, sorbitan ester, propylene glycol ester, and sucrose ester.
Examples of the nitrogen-containing type include fatty acid alkanolamide (for example, coconut fatty acid diethanolamide), polyoxyethylene alkylamine (for example, polyoxyethylene laurylamine), polyoxyethylene alkylamide (for example, polyoxyethylene lauric acid amide), and the like. Can be mentioned. Moreover, a fluorine-type surfactant, an acetylene containing nonionic surfactant (For example, diisobutyl dimethyl butynediol polyoxyethylene glycol ether) etc. are mentioned.

  As cationic surfactants, alkylamine salts (for example, coconut amine acetate, stearylamine acetate), quaternary ammonium salts (for example, lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, cetyltrimethylammonium chloride, distearyldimethylammonium) Chloride, alkylbenzyldimethylammonium chloride), alkylpyridinium salts (for example, cetylpyridinium chloride) and the like.

  Amphoteric surfactants include alkylbetaine type (for example, lauric betaine (lauryldimethylaminoacetic acid betaine, stearylbetaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolium betaine), amine oxide type (for example, lauryl). Dimethylamine oxide) and the like.

The surfactant is preferably an anionic surfactant, more preferably a surfactant having a sulfo group, and still more preferably a surfactant having a phenyl group and a sulfo group at the same time. Examples of the surfactant having a phenyl group and a sulfo group at the same time include alkylbenzene sulfonic acid, alkyl diphenyl ether disulfonic acid, and salts thereof, and alkyl diphenyl ether disulfonic acid is particularly preferable.
Examples of the salt include ammonium salts (for example, salts with ammonia and triethanolamine), alkali metal salts (for example, lithium salts, sodium salts, potassium salts), halogens and the like.
However, when the substrate to be polished 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.

  (E) As the hydrophilic polymer, 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 ether, polypropylene glycol alkenyl ether, alkyl polypropylene glycol, alkyl polypropylene glycol alkyl ether, alkyl polypropylene glycol alk Ethers such as ruether, alkenyl polypropylene glycol, alkenyl polypropylene glycol alkyl ether and alkenyl polypropylene glycol alkenyl ether; polysaccharides such as alginic acid, pectic acid, carboxymethylcellulose, curdlan and pullulan; amino acid salts; polyaspartic acid, polyglutamic acid, polylysine, Polymalic acid, polymethacrylic acid, polymethacrylic acid ammonium salt, polymethacrylic acid sodium salt, polymaleic acid, polyitaconic acid, polyfumaric acid, poly (p-styrenecarboxylic acid), polyacrylic acid, polyacrylamide, aminopolyacrylamide, polyacrylic Ammonium salt, polyacrylic acid sodium salt, polyamic acid, polyamic acid ammonium salt, polyamic acid sodium salt Polycarboxylic acids and salts thereof such as potassium salt and polyglyoxylic acid; polyvinyl alcohol, vinyl polymers such as polyvinyl pyrrolidone and acrolein and the like.

However, when the substrate to be polished is a silicon substrate for a semiconductor integrated circuit or the like, contamination with alkali metal, alkaline earth metal, halide, etc. is not desirable. In the case of taking a structure, an ammonium salt is desirable. This is not the case when the substrate to be polished is a glass substrate or the like.
Among the above exemplified compounds, the hydrophilic polymer is preferably a hydrophilic polymer having an amide bond, and specifically, polyacrylic acid, polyacrylamide, polyvinyl pyrrolidone, polyvinyl alcohol and the like are preferable.

  The total amount of (e) surfactant and / or (f) hydrophilic polymer added is preferably 0.001 to 10 g in 1 L of the polishing composition when used for polishing. It is more preferable to set it as 01-5g, and it is especially preferable to set it as 0.01-3g. That is, the addition amount of the surfactant and / or the hydrophilic polymer is preferably 0.001 g or more for obtaining a sufficient effect, and is preferably 10 g or less from the viewpoint of preventing the CMP rate from being lowered.

Only one surfactant may be used, or two or more surfactants may be used in combination. As for the hydrophilic polymer, one kind may be used alone, or two or more kinds may be used in combination.
Moreover, as a weight average molecular weight of these surfactant and / or hydrophilic polymer, 500-100000 are preferable, and 2000-50000 are especially preferable.

In the present invention, in addition to the compound represented by the general formula (I), it is effective to use in combination with the following compounds conventionally used as anticorrosives for polishing compositions.
Anticorrosives that can be used in combination include 1,2,3,4-tetrazole, 5-amino-1,2,3,4-tetrazole, 5-methyl-1,2,3,4-tetrazole, 1H-tetrazole- 5-acetic acid, 1H-tetrazole-5-succinic acid, 1,2,3,4-tetrazole, 5-amino-1,2,3,4-tetrazole, 5-methyl-1,2,3,4-tetrazole 1H-tetrazole-5-acetic acid, 1H-tetrazole-5-succinic acid, 1,2,3-triazole, 4-amino-1,2,3-triazole, 4,5-diamino-1,2,3- Triazole, 4-carboxy-1H-1,2,3-triazole, 4,5-dicarboxy-1H-1,2,3-triazole, 1H-1,2,3-triazole-4-acetic acid, 4-carboxy -5-carboxyme 1H-1,2,3-triazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, 3-carboxy- 1,2,4-triazole, 3,5-dicarboxy-1,2,4-triazole, 1,2,4-triazole-3-acetic acid, 1H benzotriazole, 1H-benzotriazole-5-carboxylic acid, etc. Can be mentioned.

Particularly preferably, the compound represented by the general formula (III) is 0.001% by mass or more. Examples of such a compound include a compound represented by the general formula (III) in which R ³ is a hydrogen atom or an alkyl group which may have a substituent, R ⁴ is a hydrogen atom, an alkyl group, an aryl group, an acyl group, a carbamoyl group, a carboxy group Represents a hydroxy group, and may further have a substituent. Examples of the substituent that can be introduced include an alkyl group, a phenyl group, a hydroxy group, a carboxyl group, a sulfo group, a carbamoyl group, an amide group, an amino group, An alkoxy group and the like are preferable, and specific examples thereof include the following compounds. These compounds are preferable even in a small amount because of their high anticorrosive effect.

<PH of polishing composition>
In the polishing composition of the present invention, due to the reactivity and adsorptivity 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 appropriately set the kind of component, the amount added, or the pH.
The pH of the polishing composition of the present invention is preferably from 3.0 to 12.0, more preferably from 8.0 to 12.0, from the viewpoint of planarization performance. The pH can be easily adjusted by appropriately selecting and adding a buffer, an alkali agent, an inorganic acid, and the like.

[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 10% by mass or less, more preferably 1% by mass or less, most preferably in the range of 0.00001 to 0.1% by mass. Exhibits excellent effects.

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

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

[Polishing method]
The polishing composition of the present invention is a concentrated liquid, and when used, is diluted by adding water, or each component is mixed in the form of an aqueous solution described in the next section, and if necessary, In some cases, it is diluted with water to make a working solution or prepared as a working solution.
The polishing method using the polishing composition of the present invention (polishing method of the present invention) can be applied to any case, and has a conductor film made of copper or a copper alloy and a barrier film in a semiconductor device manufacturing process. This is a method of chemically and mechanically polishing a substrate.
In the polishing method of the present invention, the polishing composition of the present invention is supplied to a polishing pad on a polishing surface plate, and the polishing surface plate is rotated so that the polishing pad is made of a conductor film made of copper or a copper alloy. A mode in which polishing is carried out by relative movement while being in contact with a surface to be polished of a substrate having a barrier film is preferable.

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 20 kPa or less. In order to satisfy the uniformity of the polishing rate within the wafer surface and the flatness of the pattern, 6 More preferably, it is ˜15 kPa.

During polishing, the polishing composition is continuously supplied to the polishing pad with a pump or the like. Although the supply amount is not limited, it is preferable that the surface of the polishing pad is always covered with the polishing composition.
After the polishing, the semiconductor substrate 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. When the polishing composition of the present invention is used, polishing is performed. The subsequent detergency becomes good. This is presumed to be due to electrostatic repulsion between the abrasive grains and the wiring metal.
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 containing at least one of an oxidizing agent, an acid, an additive, and a surfactant in advance, and a component obtained by adding up the components contained in the aqueous solution and the components of the polishing composition to be diluted is polished. It becomes a component at the time of grind | polishing using the composition for water.
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 polishing liquid composition can be prepared.

As a method of diluting the concentrated polishing composition by adding water, the pipe for supplying the concentrated polishing composition and the pipe for supplying the water are mixed together and mixed, mixed and diluted for polishing. There is a method of supplying a composition to a 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 polishing composition can be appropriately selected within the range of 10 to 1000 ml / min, but considering the physical properties of the polishing composition of the present invention, it is preferably 400 ml / min or less, preferably 100 to 400 ml / min. A range of min is more preferable.

As a method of diluting and polishing the concentrated polishing composition with an aqueous solution or the like, a pipe for supplying the polishing composition and a pipe for supplying water or an aqueous solution are independently provided, and a predetermined amount of liquid is supplied from each of them. And polishing while 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 a concentrated polishing composition and water are mixed in one container and then mixed, and then the mixed polishing composition is supplied to a polishing pad for polishing.

In another polishing method of the present invention, the component to be contained in the polishing composition is divided into at least two components, and when these components are used, they are diluted by adding water and supplied to the polishing pad on the polishing platen. In this method, the surface to be polished and the polishing pad are moved relative to each other and brought into contact with the surface to be polished.
For example, an oxidant is one component (A), an acid, an additive, a surfactant, and water are one component (B), and when they are used, the component (A) and the component are made with water. Dilute (B) for 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 components are used, water is added to dilute the component (A) and the component (B).
In this example, three pipes for supplying the component (A), the component (B), and water are required, and dilution mixing is performed by combining the three pipes into one pipe that supplies the polishing pad. There is a method of mixing in the pipe. In this case, it is also possible to combine the two pipes and then connect the other one pipe.

For example, this is a method in which a constituent component containing an additive that is difficult to dissolve is mixed with another constituent component, a mixing path is lengthened to ensure a dissolution time, and then a water pipe is further coupled.
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. The diluted polishing composition is supplied to the polishing pad.

  In the above polishing method, one constituent component excluding the oxidizing agent is set to 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 are added. When diluting and using, it can also be made 40 degrees C or less after mixing. Since solubility becomes high when temperature is high, it is a preferable method for increasing the solubility of raw materials with low solubility of the polishing composition.

  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 the heated component solution dissolved and a means for stirring the liquid containing the precipitate, feeding the liquid and heating and dissolving the piping can be employed.

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

〔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.
Further, the surface that contacts the polished 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 polishing composition of the present invention preferably has a diameter of 200 mm or more, particularly preferably 300 mm or more. The effect of the present invention is remarkably exhibited when the thickness is 300 mm or more.

  Hereinafter, the present invention will be described by way of examples. The present invention is not limited to these examples. “Part” means “% by mass”.

[Example 1]
-Polishing composition-
(A) Amine compound (described in Table 1) 0.1 part (b) 1.0 part ammonium peroxodisulfate (APS) (c) Abrasive grains: colloidal silica particles (primary particle size 35 nm) 0 parts-pH adjuster (described in Table 1) Adjusted to pH 9.0-5-aminotetrazole 0.05 parts-Surfactant: 0.5 parts of potassium dodecylbenzenesulfonate

  A polishing composition (polishing liquid) was prepared in the same manner as in Example 1 except that the amine compound and pH adjuster of Example 1 were changed as shown in Table 1.

  The polishing rates of the copper film, the tantalum film, and the titanium film of the polishing compositions prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were evaluated by the following polishing method. The evaluation results are shown in Table 2.

<Evaluation method of polishing rate>
An apparatus “FREX-300” manufactured by Ebara Corporation was used as a polishing apparatus, and the film provided on each wafer was polished while supplying slurry under the following conditions, and the polishing rate was calculated.

The film thicknesses of the copper film, tantalum film, and titanium film were measured from the electrical resistance before and after polishing, and the polishing rate was calculated. Specifically, it calculated using the following formula.
Polishing rate (nm / min) = (thickness of copper film or barrier film before polishing−thickness of copper film or barrier film after polishing) / polishing time

(Polishing conditions)
-Base A commercially available copper film, tantalum, or titanium film wafer was used.
Table rotation speed 104rpm
・ Head speed: 105rpm
・ Polishing pressure 10.5kPa
・ Polishing pad Rodel Nitta Co., Ltd. Part No. IC-1400
・ Slurry supply rate 200ml / min

  From Table 2, Examples 1 to 5 using the amine compound of the present invention are excellent in selective polishing properties of copper and tantalum and copper and titanium. In particular, Example 1 corresponding to the general formula (II) has a copper polishing rate. It can be seen that the selective polishing properties of copper and tantalum and copper and titanium are further excellent.

Claims (7)

In a semiconductor device manufacturing process, a metal polishing composition used for chemical mechanical polishing of a conductor film mainly composed of copper or a copper alloy,
A metal polishing composition comprising: (a) a compound represented by the following general formula (I); (b) peroxodisulfate; and (c) abrasive grains.

In general formula (I), R ¹ is an alicyclic or aliphatic alkyl group having no substituent having 3 to 12 carbon atoms, or an alicyclic or aliphatic group having 3 to 12 carbon atoms having an amino group as a substituent. Or an alicyclic or aliphatic alkyl group having 3 to 10 carbon atoms having a hydroxyl group as a substituent. R ¹ in the general formula (I) is a linear alkyl group having 6 to 7 carbon atoms, an alkyl group having 4 to 5 carbon atoms having a branched chain, or an alicyclic alkyl group having 6 to 7 carbon atoms. The metal polishing composition according to claim 1. The metal polishing composition according to claim 1, wherein R ¹ in the general formula (I) is a C 3-10 alkyl group having a hydroxyl group as a substituent. The metal polishing composition according to any one of claims 1 to 3, wherein the compound represented by the general formula (I) is a compound represented by the following general formula (II).

In general formula (II), R ² represents an aliphatic alkylene group having 4 to 12 carbon atoms or an alicyclic alkylene group having 4 to 12 carbon atoms. The metal polishing composition according to claim 4, wherein R ² in the general formula (II) is an aliphatic alkylene group having 4 to 6 carbon atoms. Furthermore, the metal polishing composition of any one of Claims 1-5 containing the compound represented with the following general formula (III).

In general formula (III), R ³ represents a hydrogen atom or an optionally substituted alkyl group, R ⁴ represents a hydrogen atom, an alkyl group, an aryl group, an acyl group, a carbamoyl group, a carboxy group, or a hydroxy group, Further, it may have a substituent, and the substituent that can be introduced represents an alkyl group, a phenyl group, a hydroxy group, a carboxyl group, a sulfo group, a carbamoyl group, an amide group, an amino group, or an alkoxy group.   The metal polishing composition according to any one of claims 1 to 6 is supplied to a polishing pad on a polishing plate, and the polishing pad is rotated by rotating the polishing plate. A chemical mechanical polishing method, wherein polishing is performed by making relative movement while contacting with a polishing surface.