JP2008016678A - Composition for polishing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for polishing that has practical polishing speed, also has high polishing selectivity to copper that is a metal wiring material, tantalum used as a barrier layer, and an insulation film that is an underlayer, suppresses the occurrence of erosion, and is used suitably for a semiconductor CMP process. <P>SOLUTION: The slurry for polishing contains: a copolymer resin A containing at least one type of monomer selected from a group, comprising an amido group, a hydroxyl group, a carbonyl group, a nitrile group, a pyridyl group, a glycidyl group, an acetoacetyl group, a sulfonyl group, or an alkoxy group by 10-99 pts.wt. to 100 pts.wt. of the entire monomer; and an abrasive grain B where the modulus of elasticity is in the range of 0.01-300,000 MPa. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a wiring formation process, which is a process for manufacturing a semiconductor device, and polished without damaging the surface of an insulating film formed on a semiconductor wafer, a metal wiring such as aluminum and copper, a barrier layer such as tantalum, and the like. The present invention relates to a polishing composition capable of forming a flat semiconductor wafer surface.

  In recent years, in a wiring forming process, which is a process for manufacturing a semiconductor device, a groove for forming a wiring is dug on an insulating film formed on a semiconductor wafer, and a metal film for wiring is plated so as to cover the groove. A technique for embedding using a method or the like and forming a metal wiring by removing an excessive metal film is used. Here, a polishing method called CMP (Chemical and Mechanical Polishing) is used to remove the excessive metal film and planarize the surface of the semiconductor wafer. CMP is not a mechanical polishing using mere abrasive grains, but a method of mechanically polishing the surface to be polished that has been modified by applying a chemical action, and the cooperation between the chemical action and the mechanical action. Therefore, a controlled integration of chemical and mechanical action is important.

Conventionally, inorganic abrasive grains such as ceria, alumina, and silica have been used as abrasive grains for CMP. However, these inorganic abrasive grains have high hardness, and problems such as scratching, dishing, and erosion have not been solved when a metal having low hardness such as copper is used as a metal for wiring formation.
Scratches are caused when the abrasive grains are too hard with respect to the material to be polished or the abrasive grains aggregate to locally overpolish the surface to be polished, and there is a problem of breaking the wiring of the semiconductor device.
The dishing may be caused by distortion of the polishing pad during polishing, or the type and amount of the pH adjusting agent or complex forming agent for adjusting the liquid property of the metal polishing composition and compatibility with the surface to be polished. Poorly occurs when the chemical properties of the surface to be polished are mismatched with the mechanical polishing characteristics. The form is a concave shape that is generated when the metal film of the wiring portion is polished more excessively than the surroundings at the center of the wiring.
Erosion is a generation of a concave shape larger than dishing that occurs in densely packed wiring patterns, and is a barrier film that prevents excessive polishing due to excessively hard abrasive grains and diffusion of metal films, insulating films, and metals for wiring This is caused by low polishing selectivity for each object to be polished on a non-uniform polished surface made of, for example.
Dishing and erosion cause an increase and variation in wiring resistance, and further cause a short circuit between wiring layers formed in an upper layer.
When scratch, dishing, and erosion occur in this way, the reliability of the semiconductor device is significantly reduced, and the manufacturing yield is greatly reduced.

  In particular, in order to improve the performance of semiconductor devices, the 1/2 wiring width on the insulating film has been reduced from 130 nm to 90 nm, and further to 65 nm, and problems such as scratches, dishing, and erosion have become more serious. There is a need for a polishing composition that minimizes damage to the surface to be polished while ensuring a polishing rate within a practical range.

In order to solve these problems, a polishing composition has been developed in which the inorganic abrasive grains are made of silica softer than alumina, and the metal to be polished forms a passive state and the metal ions are not easily eluted, so that polishing is performed from the neutral to the alkaline side. ing. However, even if the inorganic abrasive grains are changed from alumina to silica, the generation of scratches due to the abrasive grains themselves is suppressed, but it has been possible to solve the occurrence of scratches and erosion due to the aggregates of abrasive grains and the shavings of the metal to be polished. Absent.
On the other hand, in Japanese Patent No. 3172008 (Patent Document 1), a polishing method using particles made of an organic polymer compound or particles mainly composed of carbon selected from the group consisting of amorphous carbon and carbon black as abrasive particles. Is disclosed. However, the problem is to completely remove the abrasive grains remaining on the surface to be polished after polishing, and the specifically disclosed organic polymer compounds are methacrylic resins and polystyrene resins having no functional groups, and Since an oxidizing agent that oxidizes the surface of the polishing metal is not added, the chemical action with the metal to be polished does not work at all, and as a result, an industrially meaningful polishing rate is not obtained.

Japanese Patent Application Laid-Open No. 2001-55559 (Patent Document 2) discloses an aqueous dispersion for chemical mechanical polishing containing organic particles having a functional group capable of reacting with a surface to be polished. Although improved, there has been no evaluation of dishing or erosion.
Japanese Patent Application Publication No. 2004-532521 (Patent Document 3) discloses a CMP polishing composition containing a water-soluble carboxylic acid polymer, but polishing is performed on the acid side in the case of a metal corrosion region, that is, copper. For this reason, there is a problem that a slit-shaped depression called a fang is easily formed when a copper corrosion reaction proceeds at the interface portion between the copper layer and the barrier metal layer and copper ions are eluted.
Japanese Patent No. 3337464 (Patent Document 4) discloses a metal polishing liquid containing two different types of protective film forming agents. Specifically, benzotriazoles are disclosed as the first protective film forming agent, and water-soluble polymers such as polyacrylic acid and polymethacrylic acid are disclosed as the second protective film forming agent. The effect of suppressing etching is low and it cannot be expected to suppress the occurrence of dishing. Further, there is a risk that the viscosity increases due to neutralization and the fluidity of the polishing liquid decreases, thereby reducing the polishing rate and the polishing quality. Further, since it does not substantially contain abrasive grains, an industrially meaningful polishing rate cannot be obtained.
JP 2003-313541 A (Patent Document 5) suppresses polishing of tantalum used as a barrier metal material by using resin particles having a lower elastic modulus than conventional inorganic abrasive grains, thereby polishing copper and tantalum. Although it is disclosed that the selectivity can be improved, the polishing rate of copper is slower than the conventional inorganic abrasive grains, so that a sufficient polishing selection ratio of copper and tantalum cannot be obtained, and erosion is completely prevented. It is expected to be difficult to suppress.
Japanese Patent No. 3172008 JP 2001-55559 A JP-T-2004-532521 Japanese Patent No. 3337464 Japanese Patent Laid-Open No. 2003-313541

  The present invention has a high polishing selectivity (hereinafter referred to as copper) with respect to copper as a metal wiring material, tantalum used as a barrier layer, and an insulating film as an underlayer while maintaining an industrially significant polishing rate. / Tantalum / insulating film polishing selectivity, etc.), and an object of the present invention is to provide a polishing composition suitable for use in a semiconductor CMP process that suppresses the occurrence of erosion to the limit.

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, the polishing composition of the present invention is at least one selected from the group consisting of amide group, hydroxyl group, carbonyl group, nitrile group, pyridyl group, glycidyl group, acetoacetyl group, amino group, sulfonyl group and alkoxy group. Copolymer resin (A) containing 10 to 99 parts by weight of the above monomers with respect to 100 parts by weight of all monomers, abrasive grains (B) having an elastic modulus in the range of 0.01 to 300000 MPa, It is polishing composition characterized by including.
Furthermore, the monomer contained in 10 to 99 parts by weight with respect to 100 parts by weight of the total monomers is acrylamide, methacrylamide, dimethyl (meth) acrylamide, 2-hydroxy (meth) acrylate, acetoacetoxyethyl (meth) acrylate. (Meth) acrylonitrile, glycidyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, at least one monomer selected from the group consisting of acryloylmorpholine and vinylpyrrolidone This is one of the preferred embodiments of the invention.
The abrasive grains (B) are at least one selected from the group consisting of acrylic resin, phenol resin, melamine resin, urethane resin, polyolefin resin, polyester resin, polyamide resin, polyimide resin, polysiloxane resin and colloidal silica. It is one of the preferable aspects of this invention that it is an abrasive grain.
Further, it is one of the preferred embodiments of the present invention that it further contains an oxidizing agent, a water-soluble compound capable of forming a complex with the metal to be polished, and an anticorrosive, and particularly the oxidizing agent is hydrogen peroxide. The water-soluble compound capable of forming a complex with the metal to be polished is at least one water-soluble compound selected from carboxylic acids, amines, amino acids and ammonia, which suppresses high polishing rate and dishing. From the viewpoint of

  Since the polishing composition of the present invention contains a copolymer resin having a specific functional group, an oxidizing agent, and a water-soluble compound capable of forming a complex with the metal to be polished, a high polishing rate and a high copper / tantalum / insulation Film polishing selectivity is obtained, and since the elastic modulus of the abrasive grains is limited to a range of 0.01 to 300,000 MPa, high copper / tantalum / insulating film polishing selectivity can be obtained and erosion can be minimized. It is possible to suppress.

The polishing composition of the present invention is at least one selected from the group consisting of amide group, hydroxyl group, carbonyl group, nitrile group, pyridyl group, glycidyl group, acetoacetyl group, amino group, sulfonyl group and alkoxy group. A copolymer resin (A) containing 10 to 99 parts by weight of the monomer, and abrasive grains (B) having an elastic modulus in the range of 0.01 to 300000 MPa. It is preferable that the composition further contains an additive such as a water-soluble compound and an anticorrosive capable of forming a complex with an oxidizing agent / metal to be polished.
Each component will be specifically described below.

(Copolymer resin (A))
In the monomer constituting the copolymer resin (A) used in the present invention, the functional group of the monomer contained in 10 to 99 parts by weight with respect to 100 parts by weight of all monomers forms an anion. It is preferable to have difficult characteristics. Examples of functional groups that are difficult to form anions include amide groups, hydroxyl groups, carbonyl groups, nitrile groups, pyridyl groups, glycidyl groups, acetoacetyl groups, amino groups, sulfonyl groups, and alkoxy groups.
Examples of vinyl monomers that are difficult to form anions contained in the monomer constituting the copolymer resin (A) used in the present invention include acrylamide, methacrylamide, acryloylmorpholine, dimethyl (meth) acrylamide, and 2-hydroxyethyl. (Meth) acrylate, vinyl alcohol, (meth) acrylonitrile, vinylpyrrolidone, acetoacetoxyethyl (meth) acrylate, glycidyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and the like.
The composition of the monomer constituting the copolymer resin (A) is such that the monomer having a functional group that hardly forms the anion with respect to 100 parts by weight of the total monomers constituting the copolymer resin (A). It is preferably 10 to 99 parts by weight and 1 to 90 parts by weight of other monomers from the viewpoint of obtaining a high polishing rate.
The content of the copolymer resin (A) with respect to the entire polishing composition is preferably 1 to 20% by weight, particularly preferably 3 to 10% by weight. When the content of the copolymer resin (A) is less than 1% by weight, the chemical interaction between the metal to be polished and the copolymer resin (A) does not proceed sufficiently, and the target polishing rate may not be achieved. . On the other hand, when the content of the copolymer resin (A) exceeds 20% by weight, the viscosity of the slurry increases, the fluidity decreases, and a sufficient polishing rate may not be achieved.
Other monomers contained in an amount of 1 to 90 parts by weight based on 100 parts by weight of the total monomers include styrene, alkyl (meth) acrylates such as methyl acrylate and methyl methacrylate, isobornyl (meth) acrylate, cyclohexyl (meta ) Functional group-containing vinyl monomers such as carboxyl group-containing vinyl monomers such as acrylate, benzyl (meth) acrylate, (meth) acrylic acid, sulfonic acid group-containing vinyl monomers such as sodium styrenesulfonate, 2- Phosphoric acid group-containing vinyl monomers such as methacroyloxyethyl acid phosphate, vinyl acetate and the like. If necessary, crosslinkable vinyl monomers may be used. Examples of such crosslinkable vinyl monomers include methylenebis (meth) acrylamide, divinylbenzene, polyethylene glycol chain-containing di (meth) acrylate, etc. Can be illustrated. Moreover, you may contain a 2 or more vinyl group as a crosslinkable vinyl monomer.

（文献１）Ｍａｒｋ、Ｊ．Ｅ．、Ｐｏｌｙｍｅｒ Ｄａｔａ Ｈａｎｄｂｏｏｋ、Ｏｘｆｏｒｄ Ｕｎｉｖｅｒｓｉｔｙ Ｐｒｅｓｓ，１９９９
（文献２）Ｂｉｃｅｒａｎｏ，Ｊ．，Ｐｒｅｄｉｃｔｉｏｎ ｏｆ Ｐｏｌｙｍｅｒ Ｐｒｏｐｅｒｔｉｅｓ，Ｍａｒｃｅｌ Ｄｅｋｋｅｒ，２００２
（文献３）Ｂｕｃｈｈｏｌｚ，Ｆ．Ｌ．，Ｔｈｅ Ｓｔｒｕｃｔｕｒｅ ａｎｄ Ｐｒｏｐｅｒｔｉｅｓ ｏｆ Ｓｕｐｅｒａｂｓｏｒｂｅｎｔ Ｐｏｌｙａｃｒｙｌａｔｅｓ．Ｉｎ：Ｍｏｄｅｒｎ Ｓｕｐｅｒａｂｓｏｒｂｅｎｔ Ｐｏｌｙｍｅｒ Ｔｅｃｈｎｏｌｏｇｙ，Ｗｉｌｅｙ，１９９８．Ｐａｇｅ １７２．
（文献４）Ｓｃｈｒｏｅｄｅｒ，Ｕ．Ｐ．，Ｏｐｐｅｒｍａｎｎ，Ｐｒｏｐｅｒｔｉｅｓ ｏｆ ＰｏｌｙｅｌｅｃｔｒｏｌｙｔｅＧｅｌｓ.Ｉｎ：Ｐｈｙｓｉｃａｌ Ｐｒｏｐｅｒｔｉｅｓ ｏｆ Ｐｏｌｙｍｅｒｉｃ Ｇｅｌｓ，Ｗｉｌｅｙ，１９９６．Ｐａｇｅ３０．

結晶性あるいはポリマー鎖の分子配列の方位を制御した有機材料を粉砕することによって、さらに高い弾性率の樹脂粒子を得ることができる。表２に、砥粒（B）として好ましい結晶性及び分子配列を制御した材料の弾性率の文献値を示す。
表２

砥粒（Ｂ）として有機粒子を用いる場合、特に好ましいものとしてはアクリルエマルション樹脂・不飽和ポリエステル樹脂・ポリイミド樹脂・ポリアミド樹脂・ポリウレタン樹脂・ポリオレフィン樹脂・フェノール樹脂・メラミン樹脂及びポリ酢酸ビニル樹脂等の樹脂の微粒子や、有機−無機複合粒子としては無機材料の弾性率を低下させるアルキル基等の官能基を有するポリシロキサンの微粒子等を例示することが出来る。これらを単独であるいは組み合わせて使用することが出来る。
本発明の砥粒（Ｂ）に用いる樹脂粒子は公知の水溶液重合・乳化重合・分散重合等により製造することができるが、これらに限定されるものではない。 (Abrasive grain (B))
The abrasive grains (B) used in the present invention are preferably abrasive grains having an elastic modulus in the range of 0.01 to 300,000 MPa from the viewpoint of obtaining a high polishing rate. Further, from the viewpoint of suppressing the occurrence of defects such as erosion, it is more preferable to use abrasive grains having an elastic modulus in the range of 0.01 to 10000 MPa. If the elastic modulus of the abrasive grains is less than 0.01 MPa, a sufficient polishing rate may not be obtained, and if it exceeds 300,000 MPa, the copper / tantalum polishing selectivity is lowered and erosion is likely to occur. .
Abrasive grains made of organic particles may be used as the abrasive grains, inorganic abrasive grains may be used if the elastic modulus is in the range of 0.01 to 300,000 MPa, and particles made of an organic-inorganic composite material are used. It doesn't matter.
If the abrasive grains are organic particles, the elastic modulus can be measured by using a dynamic viscoelasticity tester after evaporating moisture from the polishing composition and processing it into a film. The elastic modulus can also be calculated by calculation using the atomic group contribution method based on the molecular structure of the monomer constituting the resin and the glass transition point. “Polymer-Design Tools” can be exemplified as polymer property estimation software for performing such calculation.
Table 1 shows organic materials preferable as the abrasive grains (B), literature values of elastic modulus of these organic materials, and elastic modulus calculated using “Polymer-Design Tools”.


































Table 1

(Reference 1) Mark, J. et al. E. , Polymer Data Handbook, Oxford University Press, 1999
(Reference 2) Bicerano, J. et al. , Prediction of Polymer Properties, Marcel Dekker, 2002
(Reference 3) Buchholz, F .; L. The Structure and Properties of Superabsorbent Polyacrylates. In: Modern Supersorbent Polymer Technology, Wiley, 1998. Page 172.
(Reference 4) Schroeder, U. P. , Oppermann, Properties of PolyelectrolytesGels. In: Physical Properties of Polymeric Gels, Wiley, 1996. Page30.

By pulverizing an organic material in which the crystallinity or the orientation of the molecular arrangement of the polymer chain is controlled, resin particles having a higher elastic modulus can be obtained. Table 2 shows literature values of the elastic modulus of the material having controlled crystallinity and molecular arrangement preferable as the abrasive grains (B).
Table 2

When organic particles are used as the abrasive grains (B), particularly preferred are acrylic emulsion resin, unsaturated polyester resin, polyimide resin, polyamide resin, polyurethane resin, polyolefin resin, phenol resin, melamine resin, and polyvinyl acetate resin. Examples of the resin fine particles and organic-inorganic composite particles include polysiloxane fine particles having a functional group such as an alkyl group that lowers the elastic modulus of the inorganic material. These can be used alone or in combination.
The resin particles used for the abrasive grains (B) of the present invention can be produced by known aqueous solution polymerization / emulsion polymerization / dispersion polymerization, but are not limited thereto.

Vinyl monomers that can be used to obtain acrylic resins that form fine particles with an elastic modulus of 0.01 to 300,000 MPa include styrene, alkyl (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, and benzyl (meth). Hydrophobic vinyl monomers such as acrylate, cyano group-containing vinyl monomers such as (meth) acrylonitrile, amide group-containing vinyl monomers such as (meth) acrylamide, and carboxyl group-containing vinyl monomers such as (meth) acrylic acid A monomer, a hydroxyl group-containing vinyl monomer such as 2-hydroxyethyl (meth) acrylate, a glycidyl group-containing vinyl monomer such as glycidyl (meth) acrylate, and an acetoacetoxy group-containing vinyl monomer such as acetoacetoxyethyl (meth) acrylate. Mer, sulfone such as sodium styrenesulfonate Examples thereof include functional group-containing vinyl monomers such as acid-containing vinyl monomers, and phosphate group-containing vinyl monomers such as 2-methacryloxyethyl acid phosphate. If necessary, crosslinkable vinyl monomers may be used. Examples of such crosslinkable vinyl monomers include methylenebis (meth) acrylamide, divinylbenzene, polyethylene glycol chain-containing di (meth) acrylate, etc. Can be illustrated. Moreover, you may contain a 2 or more vinyl group as a crosslinkable vinyl monomer.
The content of the abrasive grains (B) in the polishing slurry is preferably 1 to 20% by weight, particularly preferably 1.5 to 10% by weight. If the content of the abrasive grains (B) is too small, the polishing rate may be reduced. On the other hand, if it exceeds 20% by weight, the polishing quality may be deteriorated, such as scratching or dishing.

(Molecular weight regulator)
When the copolymer resin (A) is polymerized, a mercaptan such as t-dodecyl mercaptan or n-dodecyl mercaptan, an alcohol such as isopropanol, or the like may be used as necessary.

(Polymerization initiator)
In order not to cause unnecessary damage to the metal wiring to be polished, it is desirable that no metal component is present in the polishing slurry. In addition to the monomers constituting the copolymer resin (A), the polymerization slurry, a surfactant, a water-soluble compound capable of forming a complex with the metal to be polished, a molecular weight adjusting agent, a pH adjusting agent, etc. are included in the polishing slurry. As the material that can be obtained, it is preferable to use a material that does not contain a metal.
Examples of the polymerization initiator not containing metal include organic peroxides such as hydrogen peroxide, ammonium persulfate, cumene hydroperoxide, t-butyl hydroperoxide, and benzoyl peroxide, azobiscyanovaleric acid, 2,2′- Examples include azo compounds such as azobis (2-aminodipropane) dibasic acid salt, and one or more of these can be selected and used.
The polymerization initiator is preferably water-soluble, and ammonium persulfate, azobiscyanovaleric acid, 2,2′-azobis (2-aminodipropane) dibasic acid salt is preferably used.
The amount of the polymerization initiator used is generally 0.1 to 5 parts by weight with respect to 100 parts by weight of the monomer to be polymerized.

(Water-soluble compound that can form a complex with the metal to be polished)
Water-soluble compounds that can form complexes with the metal to be polished include carboxylic acids such as acetic acid, oxalic acid, malonic acid, malic acid, tartaric acid, succinic acid, citric acid, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, and triethylamine. And the like, amino acids such as glycine, aspartic acid and glutamic acid, ketones such as acetylacetone, ammonia and the like.
Of these, carboxylic acids, amines, amino acids, and ammonia are preferable, and oxalic acid, malonic acid, tartaric acid, and glycine are more preferable.
The addition amount of the water-soluble compound capable of forming a complex with the metal to be polished is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the polishing slurry. If the amount is less than 0.1 parts by weight, the effect cannot be sufficiently exhibited and the intended polishing rate may not be achieved. On the other hand, when the amount is more than 10 parts by weight, the metal to be polished may be excessively complexed and eluted to promote dishing.

(Oxidant)
Examples of the oxidizing agent include hydrogen peroxide, ammonium persulfate, and potassium persulfate, and hydrogen peroxide is preferably used.
The addition amount of the oxidizing agent is preferably in the range of 0.1 to 15 parts by weight, particularly preferably in the range of 0.5 to 5 parts by weight with respect to 100 parts by weight of the polishing slurry. If the addition amount of the oxidizing agent is less than 0.1 parts by weight, the chemical reaction between the metal to be polished and the copolymer resin (A) does not proceed and the intended polishing rate may not be achieved. On the other hand, if the addition amount of the oxidizing agent exceeds 15 parts by weight, an oxide film may be formed on the surface of the metal to be polished and passivated, and polishing may not proceed.

(PH of slurry for polishing)
The pH of the polishing slurry is preferably in the range of 7-11, more preferably in the range of 7-9. When the polishing slurry has a pH of less than 7, corrosion of the metal to be polished proceeds and metal ions are likely to elute, so that the formation of defects such as dishing and fangs may not be sufficiently suppressed. If the pH exceeds 11, the insulating film may be dissolved or partially decomposed when the semiconductor insulating film, which is the end point of polishing, and the metal film to be polished are on the same plane.

(PH adjuster)
As the pH adjuster used for adjusting the pH of the polishing slurry, conventionally known ones can be used. Metal-free basic substances are preferably used, and amines such as ammonia, methylamine, dimethylamine, triethylamine, ethylamine, dimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, tetramethylammonium hydroxide, water One or more pH adjusting agents selected from alkyl ammonium salts such as tetraethylammonium oxide can be particularly preferably used.
As the pH adjuster, the same substance as the water-soluble compound capable of forming a complex with the metal to be polished is used for the two purposes of adjusting the pH of the polishing slurry and forming a complex with the metal to be polished. You may do it.

(Other additives)
Other additives include anticorrosives, wetting agents, antistatic agents, preservatives, UV absorbers, light stabilizers, penetrants, antifoaming agents, antifoaming agents, antifoaming agents, fluidity improving agents, etc. An additive may be added. As an additive used in the polishing slurry of the present invention, it is preferable to appropriately select an additive that does not contain a metal. For example, as an anticorrosive agent, nitrogen-containing heterocyclic compounds such as benzotriazole, quinaldic acid, and quinolinic acid, and aromatic amino acids such as phenylalanine may be added alone or in combination.
The additive can be added at any time before, during, or after polymerization of the copolymer resin (A). The amount and type are not particularly limited as long as the object of the present invention can be achieved.

(Method for preparing slurry for polishing)
The copolymer resin (A) and abrasive grains (B) described so far were dispersed in water, and prepared by adding an oxidizing agent, a water-soluble compound capable of forming a complex with the metal to be polished, and an anticorrosive. A slurry can be suitably used as the polishing slurry of the present invention.
A method for preparing the slurry of the present invention is not particularly limited, but a small amount of an aqueous solution of a water-soluble compound capable of forming a complex with the metal to be polished and a copolymer resin (A) each having a pH adjusted. Stir and mix each to form a stable slurry, and then mix the abrasive grains (B) and other additives so as not to destabilize the dispersed state of the slurry, and finally adjust the pH to make it insoluble It is preferable to remove the objects and aggregates to obtain a polishing slurry.

表４

５．研磨用スラリーの調製
研磨用スラリーは、共重合樹脂（Ａ）１０重量部を水に分散させたスラリーに、アンモニアを用いてｐＨを中和した被研磨金属と錯体を形成しうる水溶性化合物を滴下混合し、研磨する直前に過酸化水素水と防食剤ベンゾトリアゾールとをそれぞれ２％と０．０４％となるように添加して調製した。各実施例と各比較例に用いた研磨用スラリーの組成を表５に示す。
表５

６．実施例と比較例の研磨用スラリーの研磨能力
各実施例と各比較例で得られた、銅とタンタルの研磨速度、及び銅とタンタルの研磨速度比、エロージョンの発生状況を表６に示す。エロージョンの発生が確認されなかったものを○、エロージョンの発生が確認されたものを×として示した。
表６

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.
Evaluation of the slurry for polishing and preparation of the slurry were carried out by the methods described below.
1. Polishing conditions for calculating the polishing rate Polishing slurry: Polishing slurry of the present invention Polishing object: Si thermal oxide film 500 nm on silicon wafer / formed by sputtering method
Seed copper for plating formed by Ta film 30nm / CVD method
150nm film / copper film 1500nm formed by plating
8 inch silicon wafer, SEM with wiring pattern
Product name # 854 silicon wafer and silicon manufactured by ATECH
Si thermal oxide film 500nm / wafer formed on wafer by sputtering method
Wafer polishing machine: MAT-ARW-681M
Polishing pad: IC-1000 / suba400
Polishing load: 3.0 psi
Polishing time: 1 min.
Slurry supply amount: 200 ml / min.
Plate rotation speed: 100rpm
Substrate side rotation speed: 96rpm
2. Method for calculating polishing rate The object to be polished was washed with ultrapure water and subjected to ultrasonic cleaning, then dried, and the film thickness before and after polishing was measured by sheet resistance measurement using a four-terminal probe. The average polishing rate was calculated from the change in film thickness and the polishing time.
3. Observation of erosion After polishing the product name # 854 manufactured by SEMATECH on which a wiring pattern is formed under the above conditions using the polishing slurry of the present invention, a cross section of a region where the wiring width (line / space) is 9/1 μm Was observed using a scanning electron microscope, and erosion was evaluated from the shape of the Ta film.
4). Synthesis of copolymer resin (A) and abrasive grains (B) (Production Examples 1 to 6 of copolymer resin (A))
A separable flask equipped with a stirrer and a reflux condenser was charged with 200 parts by weight of distilled water, replaced with nitrogen gas, and heated to 75 ° C. Next, 2.0 parts by weight of ammonium persulfate was added and dissolved. Thereafter, a mixture of the monomer having the composition shown in Table 3 and 200 parts by weight of distilled water was continuously added over 2 hours with stirring, and further aged for 2 hours to complete the polymerization reaction.
(Production Example 1 of abrasive grains (B); acrylic resin abrasive grains)
A separable flask equipped with a stirrer and a reflux condenser was charged with 260 parts by weight of distilled water and 100 parts by weight of copolymer resin (A) synthesized in Example 1 of copolymer resin (A), and the atmosphere was replaced with nitrogen gas. Then, the temperature was raised to 80 ° C. Next, 2.0 parts by weight of ammonium persulfate was added, and then the emulsion described in Table 4 Production Example 1 was emulsified in distilled water and continuously dropped into the flask over 4 hours while stirring. The polymerization reaction was completed by further aging for 4 hours.
(Production Example 2 of Abrasive Grain (B); Acrylic Resin Abrasive Grain)
A separable flask equipped with a stirrer and a reflux condenser was charged with 360 parts by weight of distilled water, and the atmosphere was replaced with nitrogen gas. Next, 2.0 parts by weight of ammonium persulfate was added, and then the monomer and distilled water emulsion described in Table 4 Production Example 2 were continuously dropped into the flask over 4 hours while stirring, and further aged for 4 hours. The polymerization reaction was formulated.
(Production Example 3 of Abrasive Grain (B); Acrylic Resin Abrasive Grain)
A separable flask equipped with a stirrer and a reflux condenser was charged with 360 parts by weight of distilled water, and the atmosphere was replaced with nitrogen gas. Next, 2.0 parts by weight of ammonium persulfate was added, and then the emulsion described in Production Example 3 in Table 4 and the emulsion of distilled water were continuously dropped into the flask over 4 hours while stirring, and further aged for 4 hours. The polymerization reaction was formulated.
(Production Example 4 of abrasive grains (B); polyimide resin abrasive grains)
Acetone solution (50 ml) containing 3,3,4,4-benzophenonetetracarboxylic dianhydride (BDTA, 1 mmol), methanol containing 3,5-diaminobenzoic acid (3,5 DBA, 0.05 mmol) Three liquids of an acetone mixed solution (25 mL) and an acetone solution (25 mL) containing 4,4′-diaminodiphenyl ether (DPE, 0.5 mmol) were prepared. Next, the above-mentioned two liquids were mixed at 25 ° C. and stirred for 10 minutes with an ultrasonic wave having a frequency of 38 kHz to cause polyamic acid fine particles to precipitate. The precipitate was collected by centrifugation and washed with xylene. The recovered polyamic acid fine particles (0.3 g) were dispersed in xylene (200 mL), and then imidized by heating at 135 ° C. for 4 hours under reflux. The imidized fine particles were collected by centrifugation, washed with xylene and purified.
(Abrasive grain (B) production example 5; polyamide resin abrasive grains)
An acetone solution (50 mL) in which 0.5 mmol of terephthalic acid dichloride was dissolved and an acetone solution (50 mL) in which 0.5 mmol of 4,4′-diaminodiphenyl ether was dissolved were prepared and cooled to 4 ° C. Next, ion-exchanged water (25 mL) was added to the 4,4′-diaminodiphenyl ether / acetone solution and stirred. Further, both solutions were mixed in an ice bath and stirred for 20 minutes with an ultrasonic wave having a frequency of 28 kHz to precipitate polyamide particles.
(Production Example 6 of abrasive grains (B); polyester resin abrasive grains)
25 parts by weight of isophthalic acid, 30 parts by weight of maleic anhydride, 26 parts by weight of propylene glycol and 9 parts by weight of ethylene glycol were mixed, and this was subjected to an esterification reaction at a temperature of 180 to 210 ° C. in a nitrogen atmosphere. A saturated polyester was obtained. Next, 100 parts by weight of the obtained unsaturated polyester was dissolved in 50 parts by weight of styrene, and 1.5 parts by weight of azoisobutyronitrile was further mixed. This mixed solution was liquefied and dispersed with stirring in an aqueous solution in which 1.5 parts by weight of polyvinyl alcohol was dissolved in 450 parts by weight of water, and the mixture was heated and stirred at 70 ° C. for 2 hours and further at 80 ° C. for 3 hours to conduct a polymerization reaction. Was completed.
(Production Example 7 of abrasive grains (B); phenol resin abrasive grains)
100 parts by weight of resorcin, 1000 parts by weight of water and 0.3 part by weight of sodium carbonate were added and stirred until completely dissolved. Next, 147 parts by weight of 37% formaldehyde aqueous solution was added and stirred, and then allowed to stand in a thermostatic bath at 80 ° C. for 72 hours, and then particles were obtained by a centrifugal separation method.
(Abrasive (B) Production Example 8; polysiloxane particle abrasive)
In a separable flask equipped with a stirrer and a reflux condenser, tetramethoxysilane 144.5 parts by weight, γ-methacryloxypropyltrimethoxysilane 23.6 parts by weight, water 19 parts by weight, methanol 30 parts by weight, cationic exchange 5 parts by weight of a resin (trade name Amberlyst 15 manufactured by Rohm & Haas Japan Co., Ltd.) was added and stirred at 65 ° C. for 2 hours. After cooling the reaction product, replace the reflux condenser with a distillation column and a condenser connected to the distillation column and an outlet, raise the temperature to 80 ° C. under normal pressure, and maintain at 80 ° C. until methanol no longer flows out. did. After methanol stopped flowing out, the pressure was reduced to 200 mmHg and the temperature was raised to 90 ° C. to advance the reaction, and then the cation exchange resin was separated to obtain siloxane particles.
Table 3

Table 4

5. Preparation of Polishing Slurry Polishing slurry is a slurry in which 10 parts by weight of copolymer resin (A) is dispersed in water, and a water-soluble compound capable of forming a complex with the metal to be polished, which has been neutralized with ammonia. The mixture was added dropwise, and immediately before polishing, hydrogen peroxide water and the anticorrosive benzotriazole were added to 2% and 0.04%, respectively. Table 5 shows the composition of the polishing slurry used in each Example and each Comparative Example.
Table 5

6). Polishing Ability of Polishing Slurries of Examples and Comparative Examples Table 6 shows the polishing rate of copper and tantalum, the polishing rate ratio of copper and tantalum, and the occurrence of erosion obtained in each example and each comparative example. The case where the occurrence of erosion was not confirmed was shown as ◯, and the case where the occurrence of erosion was confirmed was shown as x.
Table 6

  ADVANTAGE OF THE INVENTION According to this invention, the grinding | polishing slurry used for CMP used in the wiring process which manufactures a semiconductor device which suppressed generation | occurrence | production of erosion while expressing high polishing rate can be provided.

Claims (4)

  A monomer containing at least one functional group selected from the group consisting of amide group, hydroxyl group, carbonyl group, nitrile group, pyridyl group, glycidyl group, acetoacetyl group, amino group, sulfonyl group and alkoxy group A copolymer resin (A) containing 10 to 99 parts by weight with respect to 100 parts by weight of all monomers, and abrasive grains (B) having an elastic modulus in the range of 0.01 to 300,000 MPa. Polishing composition.   The polishing composition according to claim 1, wherein the monomer contained in the copolymer resin (A) in an amount of 10 to 99 parts by weight is acrylamide, methacrylamide, dimethyl (meth) acrylamide, 2-hydroxy (meth). At least one selected from the group consisting of acrylate, acetoacetoxyethyl (meth) acrylate, (meth) acrylonitrile, glycidyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, acryloylmorpholine and vinylpyrrolidone A polishing composition, which is a monomer.   3. The polishing composition according to claim 1, wherein the abrasive grains (B) are acrylic resin, phenol resin, melamine resin, urethane resin, polyolefin resin, polyester resin, polyamide resin, polyimide resin, polysiloxane resin. And at least one abrasive selected from the group consisting of colloidal silica. The polishing composition according to claim 1, further comprising an oxidizing agent, a water-soluble compound capable of forming a complex with the metal to be polished, and an anticorrosive agent. Composition.