JP4521058B2 - Surface-modified colloidal silica and polishing composition for CMP containing the same - Google Patents

Description

  The present invention relates to a surface-modified colloidal silica and a polishing composition for CMP (Chemical Mechanical Polishing) containing the same, and particularly when forming a wiring by a damascene method or the like in manufacturing a semiconductor device. The present invention relates to a polishing composition for CMP that is preferably used in the above.

  In the CMP technology, a wafer to be planarized is placed on a rotating plate, a pad is brought into contact with the wafer surface, and both the rotating disk and the pad are supplied while supplying a polishing composition between the wafer and the pad. Rotate to polish. The surface of the object to be polished is polished by the mechanical action of the abrasive grains in the polishing composition for CMP and the pad surface, and at the same time, the wafer surface is flattened by the chemical reaction between the compound in the polishing composition for CMP and the surface of the object to be polished. It becomes.

  In manufacturing a semiconductor device, when wiring is formed by a damascene method, CMP is performed to remove a surplus wiring layer and a barrier metal layer. In this two-stage polishing method, which is often performed in CMP, the wiring layer at the outermost layer is removed by polishing in the first stage polishing, and in the second stage polishing, the wiring layer, barrier metal layer, and insulation remaining in the first stage polishing are removed. A method of polishing the layer and flattening the surface is used.

  In CMP, it is required to provide a flat polishing surface that suppresses dishing and erosion, to have no polishing residue, to provide a polishing surface that suppresses scratching, and to provide a sufficient polishing rate that does not cause problems in productivity. It has been. In the case of the first stage polishing, the wiring layer made of a copper-based material such as copper or copper alloy is efficiently removed to suppress the polishing of the barrier metal layer made of a tantalum-based material such as tantalum or tantalum nitride as much as possible. Polishing is required, and in the case of the second stage polishing, non-selective polishing with a small difference in polishing rate for different materials of insulating layers made of a silica-based material such as a wiring material, a barrier metal layer, silica, or organic silica is required.

  As polishing abrasive grains used in the polishing composition for CMP, silica whose surface has been modified with an organic group has been studied. For example, Patent Document 1 discloses that a surface-modified silica represented by a removal rate modifying group represented by a dimethylsilanol group is used in a CMP slurry. As a compound for introducing a dimethylsilanol group, dimethyldichlorosilane is used. It is disclosed. Patent Document 2 discloses colloidal silica surface-modified with an aminosilane coupling agent. Patent Document 3 discloses a polishing composition for CMP containing a silane-modified abrasive in which a metal oxide abrasive having a surface metal hydroxide and a silane compound having a non-hydrolyzable substituent are combined. ing.

  The polishing composition for CMP is designed to satisfy the required characteristics by selecting and blending various components such as abrasive grains and oxidizing agents, but there is still room for improvement in various required performances. . Particularly in the first stage polishing, it is difficult to eliminate the polishing residue while suppressing dishing because of the CMP mechanism. That is, to suppress dishing, it is effective to increase the polishing suppression effect, but if the polishing suppression effect is increased, polishing residue of the object to be polished is likely to occur. In the second stage polishing, the barrier metal layer and the insulating layer are excessively polished at the boundary portion between the wiring layer, the barrier metal layer, and the insulating layer, and the barrier metal layer and the insulating layer are on the inner side as compared with the surface of the wiring layer. There is a problem that a fang that retreats to the side occurs.

JP-T-2004-534396 JP 2007-273910 A JP 2007-088499 A

  An object of the present invention is to provide a polishing composition for CMP in which the deterioration of dishing is suppressed and the polishing residue does not remain in the first stage polishing in the CMP, particularly the CMP polishing in the copper-based wiring formation by the damascene method. It is another object of the present invention to provide a polishing composition for CMP that can improve fang in the second stage polishing.

  As a result of intensive studies to solve the above problems, the present inventors have found that colloidal silica having a specific surface modification is effective in solving the above problems, and as a result, have reached the present invention. That is, the present invention provides a surface-modified colloidal silica characterized in that the surface is modified with at least one group represented by the following general formulas (1), (2) and (3). It is.

（式中、Ａ¹は、下記式（ａ１１）〜（ａ１３）、（ａ３１）〜（ａ３３）および（ａ５１）〜（ａ５３）から選ばれる基を表し、Ａ²は、下記式（ａ２１）〜（ａ２３）、（ａ４１）〜（ａ４３）および（ａ６１）〜（ａ６３）から選ばれる基を表し、Ｒ³は、水素原子または炭素数１〜３０の炭化水素基を表し、ＹはＡ²またはＲ³を表し、ＥＯはエチレンオキサイド基を表し、ＰＯはプロピレンオキサイド基を表し、ｍ、ｎ、ｐは、ｍが０〜１７０、ｎが０〜１２０、ｐが０〜１７０であり、ｍ＋ｐが０ではない数を表す。）

(In the formula, A ¹ represents a group selected from the following formulas (a11) to (a13), (a31) to (a33) and (a51) to (a53), and A ² represents the following formula (a21) to Represents a group selected from (a23), (a41) to (a43) and (a61) to (a63), R ³ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and Y represents A ² or Represents R ³ , EO represents an ethylene oxide group, PO represents a propylene oxide group, m, n, and p are m is 0 to 170, n is 0 to 120, p is 0 to 170, and m + p is Represents a non-zero number.)

（式中、Ｒ¹、Ｒ²は、炭素数１〜４のアルキル基、フェニル基または水酸基を表し、Ｘは、炭素原子数１〜１８のアルキレン基を表し、Ｒは水素原子またはメチル基を表す。）

(Wherein R ¹ and R ² represent an alkyl group having 1 to 4 carbon atoms, a phenyl group or a hydroxyl group, X represents an alkylene group having 1 to 18 carbon atoms, and R represents a hydrogen atom or a methyl group. To express.)

  The present invention also provides a polishing composition for CMP, comprising the surface-modified colloidal silica.

  ADVANTAGE OF THE INVENTION According to this invention, in CMP at the time of forming copper wiring by CMP, especially a damascene method, the dishing can be controlled and the polishing composition for CMP with no polishing residue can be provided. Further, it is possible to provide a polishing composition for CMP that can improve fang in the second stage polishing.

First, the surface-modified colloidal silica of the present invention will be described.
In the surface-modified colloidal silica of the present invention, the silanol group present on the surface of the colloidal silica serves as a reaction site, and forms a siloxane bond with the surface modifier compound, whereby the above general formulas (1) and (2 ) Or (3) is provided, or it may be modified with at least two groups selected from the above general formulas (1), (2) and (3). The groups represented by the general formulas (a11), (a21), (a31), (a41), (a51) and (a61) are formed by reacting with one silanol group present on the surface of colloidal silica. The surface modifier compound having at least one group represented by the general formula (1), (2) or (3) is bonded to silicon on colloidal silica to form a siloxane bond. To form.

  The groups represented by the general formulas (a12), (a22), (a32), (a42), (a52) and (a62) are two silanol groups present on the surface of colloidal silica and a surface modifier compound. The groups represented by the general formulas (a13), (a23), (a33), (a43), (a53) and (a63) are formed on the surface of colloidal silica. It is formed by the reaction between the three existing silanol groups and the surface modifier compound. Further, the surface-modified colloidal silica of the present invention may be surface-modified with a group other than the group represented by the general formula (1), (2) or (3). When the surface modifying group is a group represented by the general formula (1) or (3), the terminal silyloxy group may be bonded to the same colloidal silica particle, or may be bonded to different colloidal silica particles. The colloidal silica particles may be crosslinked. Whether the colloidal silica is non-cross-linked or cross-linked can be selected depending on the concentration of the colloidal silica to be modified and the modifier compound for introducing the surface modifying group and the reaction conditions. When the surface-modified colloidal silica of the present invention is used as a polishing abrasive grain of a polishing composition for CMP, when a crosslinked product is used, the particle size of the colloidal silica increases due to crosslinking, and the particle size distribution is non-uniform. It will become. Therefore, since the crosslinked product deteriorates the dispersion stability of the polishing composition for CMP, the use of the crosslinked product is not preferable.

(A11), (a12), (a13), (a21), (a22), (a23), (a31), (a) in the group represented by the general formula (1), (2) or (3) a32), (a33), (a41), (a42), (a43), (a51), (a52), (a53), (a61), (a62) and (a63) with R ¹ and R ² Examples of the alkyl group having 1 to 4 carbon atoms include methyl, ethyl, propyl, 2-propyl, butyl, secondary butyl, isobutyl, and tertiary butyl. The alkylene group may be linear, branched or may contain an alicyclic group. Specifically, methylene, ethylene, propylene, methylethylene, butylene, 1-methylpropylene, 2-methylpropylene, 1,2-dimethylpropylene, 1,3-dimethylpropylene, 1-methylbutylene, 2-methylbutylene, 3-methylbutylene, 2,4-dimethylbutylene, 1,3-dimethylbutylene, pentylene, hexylene, heptylene, octylene, ethane-1,1-diyl, propane-2,2-diyl, decane-1,10- Diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, Heptadecane-1,17-diyl, octadecane-1,18-diyl, cyclopenta -1,2-diyl, cyclopentane-1,3-diyl, cyclohexane-1,1-diyl, cyclohexane-1,2-diyl, cyclohexane-1,3-diyl, cyclohexane-1,4-diyl, methylcyclohexane -1,4-diyl, cyclohexane-1,4-dimethylene and the like. Examples of the hydrocarbon group having 1 to 30 carbon atoms represented by R ³ include methyl, ethyl, propyl, isopropyl, butyl, secondary butyl, tertiary butyl, isobutyl, amyl, isoamyl, tertiary amyl, hexyl, Cyclohexyl, cyclohexylmethyl, 2-cyclohexylethyl, heptyl, isoheptyl, tertiary heptyl, n-octyl, isooctyl, tertiary octyl, 2-ethylhexyl, nonyl, isononyl, decyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, Alkyl groups such as octadecyl; vinyl, 1-methylethenyl, 2-methylethenyl, propenyl, butenyl, isobutenyl, pentenyl, hexenyl, heptenyl, octenyl, decenyl, pentadecenyl, 1-phenylpropene-3 Alkenyl groups such as yl; phenyl, naphthyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-vinylphenyl, 3-isopropylphenyl, 4-isopropylphenyl, 4-butylphenyl, 4-isobutylphenyl, 4-tert-butylphenyl, 4-hexylphenyl, 4-cyclohexylphenyl, 4-octylphenyl, 4- (2-ethylhexyl) phenyl, 4-stearylphenyl, 2,3-dimethylphenyl, 2,4-dimethylphenyl, Alkylaryl groups such as 2,5-dimethylphenyl, 2,6-dimethylphenyl, 3,4-dimethylphenyl, 3,5-dimethylphenyl, 2,4-ditertiarybutylphenyl, cyclohexylphenyl; benzyl, phenethyl, 2-phenylpropan-2-yl, di Arylalkyl groups such as phenylmethyl, triphenylmethyl, styryl, cinnamyl and the like can be mentioned.

  In the group represented by the general formula (1), (2) or (3), when m + p is a value of n or more, the dispersion stability of the surface-modified colloidal silkworm in the CMP polishing composition is good. Yes, it is preferable because the performance can be easily controlled by the amount of the surface-modified colloidal silk in the polishing composition for CMP. Further, if m + p is small, dishing may be large, and if m + p is large, a polishing residue may be generated. Therefore, m + p is preferably 2 to 340, more preferably 2 to 250.

In the group represented by the general formula (2) or (3), when R ³ is highly hydrophobic, the dispersion stability of the surface-modified colloidal silkworm in the CMP polishing composition may deteriorate. In addition, dishing may become large. A preferred group for R ³ is an alkyl group having 1 to 8 carbon atoms, and a methyl group is more preferred.

In the group represented by the general formula (1), (2) or (3) according to the present invention, R ¹ and R ² can be easily obtained as a hydroxyl group, and the surface in the polishing composition for CMP It is preferable because the dispersion stability of the modified colloidal silkworm is good.

  As one method for producing the surface-modified colloidal silica of the present invention, for example, from a silane coupling agent having an isocyanate group and a hydroxy compound having EO or EO and PO, the general formulas (a11) and (a12 ), (A13), (a21), (a22), (a23), (a31), (a32), (a33), (a41), and (a43) having the group selected from (a43) A silane coupling agent having an isocyanate group and a colloidal may be prepared by previously synthesizing a modifier compound which gives a group represented by the formula (1), (2) or (3) and reacting the compound with colloidal silica. A method may be employed in which after reacting with silica, EO or a hydroxy compound having EO and PO is further reacted. The former method is preferably used because the reaction can be easily controlled and the production cost is low.

  Examples of the silane coupling agent having an isocyanate group include a compound represented by the following general formula (4), a hydroxy compound having EO or EO and PO, a compound represented by the general formula (5), and a modified compound. Examples of the material compound include compounds represented by general formulas (6) and (7).

(In the formula, Z represents a group that reacts with a silanol group to form a siloxane bond, R ^{4 to} R ⁷ represent Z, an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a hydroxyl group, and X represents Represents an alkylene group having 1 to 18 carbon atoms, and R ³ , EO, PO, m, n, and p are the same as those in the group represented by the general formula (1), (2), or (3). .)

  Moreover, as a method other than the method for producing the surface-modified colloidal silica, for example, from a silane coupling agent having an amino group and a (meth) acrylic compound having EO or EO and PO, the general formula (a51) , (A52), (a53), (a61), (a62) and (a63) having a group selected from the general formula (1), (2) or (3) A method of synthesizing a compound in advance and reacting it with colloidal silica may be used. After reacting a silane coupling agent having an amino group with colloidal silica, a (meth) acrylic compound having EO or EO and PO is prepared. Further, a reaction method may be used. The former method is preferably used because the reaction can be easily controlled and the production cost is low.

  The silane coupling agent having an amino group is a compound represented by the following general formula (8), and a (meth) acrylic compound having EO or EO and PO is represented by the general formula (9). Examples of the compound and the modifier compound include compounds represented by the general formula (10).

(In the formula, Z represents a group that reacts with a silanol group to form a siloxane bond, R ^{4 to} R ⁷ represent Z, an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a hydroxyl group, and X represents Represents an alkylene group having 1 to 18 carbon atoms, R represents a hydrogen atom or a methyl group, and EO, PO, m, n, and p are represented by the general formula (1), (2), or (3). As in the case of the group represented.)

  Z in the above general formulas (4), (6), (7), (8) and (10) is methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, s-butoxy group, isobutoxy group. Alkoxy groups such as t-butoxy group and phenoxy group; halogen groups such as chlorine, bromine and iodine; hydrogen; hydroxyl groups.

In order to obtain a surface-modified colloidal silica in which R ¹ and R ² , which are preferred forms of the present invention, are hydroxyl groups, those in which Z, R ⁴ , R ⁵ , R ⁶ and R ⁷ are alkoxy groups are used as raw materials Then, the reaction with colloidal silica may be performed. A ¹ is at least one group of (a11), (a12), (a13), (a31), (a32), (a33), (a51), (a52), and (a53). the it is difficult selectively controlled to, a ² likewise (a21), (a22), (a23), (a41), (a42), (a43), (a61), (a62) and ( a63) at least one group.

  In addition, it is usually difficult to modify all of the reactive silanol groups on the colloidal silica surface to a group represented by the general formula (1), (2) or (3). On the silica surface, an unreacted silanol group and / or a surface modifying group other than the group represented by the general formula (1), (2) or (3) may be present.

  When obtaining a material in which colloidal silica is modified with a surface modifying group other than the group represented by the general formula (1), (2) or (3), the material is previously modified with such a group. The group represented by the general formula (1), (2) or (3) may be introduced into the colloidal silica using the colloidal silica, which is represented by the general formula (1), (2) or (3). After introducing the group, a group other than the group represented by the general formula (1), (2) or (3) may be introduced. Examples of the compound for introducing a group other than the group represented by the general formula (1), (2) or (3) include halogenated alkylsilanes such as chlorotrimethylsilane, chlorodimethyloctadecylsilane, dichlorodimethylsilane, and trichloromethylsilane. Alkoxyalkylsilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyltriethoxysilane, methoxydimethyloctadecylsilane, dimethyloctadecylsilane; 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- ( 2-aminoethyl) aminopropylmethyldimethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, 3-isocyanate pro Le triethoxysilane, silane coupling agents such as 3-isocyanate propyl trimethoxysilane; boric acid, such as aluminate and the like.

  Although it is difficult to directly and accurately measure the degree of surface modification in the surface-modified colloidal silica of the present invention, the ratio of the surface modifier (or silane coupling agent) and colloidal silica is changed during synthesis. In this way, control becomes possible. For example, when the surface-modified colloidal silica of the present invention is used in a polishing composition for CMP, the modifier compound may be used in a proportion of 1 to 100 parts by mass with respect to 100 parts by mass of colloidal silica. In order to sufficiently suppress dishing, the amount of the modifier compound used is preferably 1 to 20 parts by mass and more preferably 1 to 10 parts by mass with respect to 100 parts by mass of colloidal silica.

  In the surface-modified colloidal silica of the present invention, the particle size of the colloidal silica subjected to surface modification is not particularly limited as long as it can be stably dispersed in water as a dispersion medium. When the colloidal silica is used in the polishing composition for CMP of the present invention, the particle diameter is preferably in the range of 1 to 400 nm, more preferably in the range of 10 to 300 nm.

  Applications other than the polishing composition for CMP of the surface-modified colloidal silica of the present invention include polymer material modifiers, polymer flocculants, adsorbents, paint additives, hard coat agents, anti-slip agents, and optical films. Antireflective agent, metal surface treatment agent, heat resistance agent, inorganic filler, inorganic binder, antistatic agent, catalyst carrier, organosol, and the like.

Next, the CMP polishing composition of the present invention will be described.
The polishing composition for CMP of the present invention contains the above-mentioned surface-modified colloidal silica as abrasive grains, and other components contained therein include an oxidant component and a heterocyclic compound component. , Organic acid component, aqueous polymer component, pH adjuster component, surfactant component, solubilizer component and the like. Since the polishing composition for CMP of the present invention has a property of giving good polishing for residual film, dishing, and scratches for removal of copper-based materials such as copper and copper alloys, it is based on the damascene method in the manufacture of semiconductor devices. Suitable for wiring formation process. In addition, the polishing composition for CMP of the present invention can be used for both the first stage polishing and the second stage polishing, and has a selective polishing property with respect to a copper-based material. Therefore, it is particularly suitable for the first stage polishing. is there.

  The content of the surface-modified colloidal silica in the polishing composition for CMP of the present invention is preferably 0.01 to 10% by mass. If the content of the surface-modified colloidal silica is less than the lower limit, the polishing rate may be slow. If the content of the surface-modified colloidal silica is higher than the upper limit, it may be difficult to suppress dishing. The content of the surface-modified colloidal silica is more preferably in the range of 0.05 to 5% by mass.

  The polishing composition for CMP of the present invention may contain a polishing abrasive component other than the surface-modified colloidal silica of the present invention. The amount used in the case of containing these is preferably 100 parts by mass or less, and more preferably 50 parts by mass or less, with respect to 100 parts by mass of the surface-modified colloidal silica of the present invention. Examples of the abrasive grains to be contained include colloidal silica, amorphous silicon dioxide, aluminum oxide, cerium oxide, silicon nitride, zirconium oxide, silicon carbide, and manganese dioxide other than the present invention. A mixture of more than one can be used.

  As the oxidant used in the above oxidant component, nitric acid, periodic acid, potassium periodate, lithium periodate, sodium periodate, potassium permanganate, lithium permanganate, sodium permanganate, Dichromic acid, potassium dichromate, lithium dichromate, sodium dichromate, hydrogen peroxide, perchloric acid, perchlorates (alkali metal salts, ammonium salts, etc.), hypochlorous acid, hypochlorous acid Examples include salts (alkali metal salts, ammonium salts, etc.), persulfuric acid, persulfates (alkali metal salts, ammonium salts, etc.), peracetic acid, t-butyl hydroperoxide, perbenzoic acid, ozone, etc. Used in one kind or a mixture of two or more kinds.

  The preferable content of the oxidant component in the polishing composition for CMP of the present invention is 0.01 to 10% by mass. If the content of the oxidizer component is less than the lower limit, a sufficient polishing rate may not be obtained, and if the content of the oxidizer component is more than the upper limit, etching cannot be controlled, which may cause problems such as dishing. is there.

  A suitable oxidizing agent for use in the first-stage polishing of the CMP polishing composition of the present invention is a persulfate that allows easy control of polishing rate and etching suppression, and ammonium persulfate is used for chemical polishing. It is more preferable because it promotes and improves the flatness of the polished surface. Further, when the polishing composition for CMP of the present invention is used for the second stage polishing, it is preferable to use hydrogen peroxide having an effect of suppressing polishing residue as an oxidizing agent.

  The above-mentioned heterocyclic compound component mainly functions as a rust preventive having an anticorrosive action on copper wiring or barrier metal, and 1,2,4-triazole, 3-amino-1H-1,2, 4-triazole, 4-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, 3-mercapto-1,2,4-triazole, 1H-tetrazole, 5-methyl- Azole monocycles such as 1H-tetrazole, 5-phenyltetrazole, 1H-tetrazol-1-acetic acid, 5-amino-1H-tetrazole; 2-mercaptobenzothiazole, 2- [2- (benzothiazolyl)] thiopropionic acid 2- [2- (benzothiazolyl)] thiobutyric acid, benzimidazole, benzotriazole, benzothiazole, 2-aminoben Thiazole, 2-amino-6-methylbenzothiazole, 1-hydroxybenzotriazole, 1-dihydroxybenzotriazole, 1-dihydroxypropylbenzotriazole, 2,3-dicarboxypropylbenzotriazole, 4-hydroxybenzotriazole, 5-hexyl Benzotriazole, [1,2,3-benzotriazolyl-1-methyl] [1,2,4-triazolyl-1-methyl] [2-ethylhexyl] amine, 4-methyl-1H-benzotriazole, 5- Examples include azole type complex rings such as methyl-1H-benzotriazole, naphthotriazole, bis [(1-benzotriazolyl) methyl] phosphonic acid, 1,5-pentamethylenetetrazole, and thiabendazole. Two or more types It is used in the compound.

  The content of the heterocyclic compound in the polishing composition for CMP of the present invention is preferably 0.0001 to 1% by mass. When the content of the heterocyclic compound is less than the lower limit, it is difficult to suppress dishing and erosion, which are the effects of use, and when the content of the heterocyclic compound is higher than the upper limit, the polishing rate is slow. Among these, benzotriazole is preferable because it is inexpensive and easily controls the anticorrosive action.

  The organic acid component is an organic acid or a salt of an organic acid, and the effect of use varies depending on the structure. For example, aliphatic organic acids, aliphatic sulfonic acids and their salts have the effect of increasing the stability of the polishing composition for CMP, and the effect of improving the polishing rate by eluting the polished metal such as copper. There is. Aromatic sulfonic acids and aromatic sulfonates have the effect of suppressing excessive etching of the metal and the like and improving the flatness of the polished surface.

  Examples of organic acids include 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, Aliphatic organics such as glycolic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, fumaric acid, lactic acid, malic acid, tartaric acid, citric acid, gluconic acid, acetic anhydride Carboxylic acid; benzoic acid, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, o-phthalic acid, m-phthalic acid, p-phthalic acid, quinaldic acid, naphthalene-1-carboxylic acid, naphthalene Aromatic carboxylic acids such as -2-carboxylic acid; methane sulfonic acid, ethane sulfonic acid, propane sulfonic acid, butane sulfonic acid, pentane sulfone Aliphatic acids such as acid, hexanesulfonic acid, heptanesulfonic acid, octanesulfonic acid, norbornenesulfonic acid, adamantanesulfonic acid, cyclohexanesulfonic acid, camphorsulfonic acid, trifluoromethanesulfonic acid, pentafluoroethanesulfonic acid, heptafluoropropanesulfonic acid Sulfonic acid; benzenesulfonic acid, p-toluenesulfonic acid, octylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, naphthalene-1-sulfonic acid, naphthalene-2-sulfonic acid, anthracenesulfonic acid, acenaphthenesulfonic acid , Aromatic sulfonic acids such as phenanthrenesulfonic acid; glycine, L (D) -alanine, L (D) -2-aminobutyric acid, L (D) -norvaline, L (D) -valine, L (D) -ro Syn, L (D) -norleucine, L (D) -isoleucine, L (D) -alloisoleucine, L (D) -phenylalanine, L (D) -proline, sarcosine, L (D) -ornithine, L (D ) -Lysine, taurine, L (D) -serine, L (D) -threonine, L (D) -allothreonine, L (D) -homoserine, L (D) -tyrosine, β- (3,4-dihydroxy) Phenyl) -L (D) -alanine, L (D) -thyroxine, 4-hydroxy-L (D) -proline, L (D) -cysteine, L (D) -methionine, L (D) -ethionine, L (D) -Lanthionine, L (D) -cystathionine, L (D) -cystine, L (D) -cysteic acid, L (D) -aspartic acid, L (D) -glutamic acid, S- (carboxymethyl)- L (D) -cis In, 4-aminobutyric acid, L (D) -asparagine, L (D) -glutamine, L (D) -arginine, δ-hydroxy-L (D) -lysine, L (D) -histidine, L (D) -Amino acids such as tryptophan; and alkali metal salts of organic acids (lithium salts, potassium salts, sodium salts), ammonium salts, amine salts, which are used in one kind or a mixture of two or more kinds.

  The content of the organic acid component in the polishing composition for CMP of the present invention is preferably 0.0001 to 10% by mass. If the content of the organic acid component is less than 0.0001% by mass, the effect of use may not be obtained. If the content of the organic acid component exceeds 10% by mass, the effect of use becomes excessive, flatness, polishing efficiency In some cases, the polishing selectivity may be lowered.

  As the water-based polymer component, water dispersion used as a water-soluble polymer, polishing abrasive grains, and polishing abrasive auxiliary agents that act to improve polishing selectivity by suppressing barrier layer polishing and stabilize the dispersion of polishing abrasive grains. Functional polymer compounds.

  The polishing composition for CMP of the present invention may contain an aqueous polymer component. Examples of the water-soluble polymer to be contained include polysaccharides such as alginic acid, pectic acid, carboxymethyl cellulose, agar, curdlan and pullulan; polyaspartic acid, polyglutamic acid, polylysine, polymalic acid, polymethacrylic acid, polyamic acid, Polycarboxylic acids such as polymaleic acid, polyitaconic acid, polyfumaric acid, poly (p-styrenecarboxylic acid), polyacrylic acid, and polyglyoxylic acid, polymethacrylic acid ammonium salt, polymethacrylic acid sodium salt, polyacrylamide, polyaminoacrylamide, Polycarboxylic acid salts, esters and derivatives exemplified by polyacrylic acid ammonium salt, polyacrylic acid sodium salt, polyamic acid ammonium salt, polyamic acid sodium salt; , Polyvinyl pyrrolidone, polyacrolein, vinyl polymers such as copolymers of polyvinyl pyrrolidone and α-olefins (ethylene, propylene, 1-butene, 1-pentene, etc.); polyethylene glycol, polypropylene glycol, alkylene glycol or polyalkylene glycol Polyalkylene glycols such as random or block adducts of ethylene oxide and propylene oxide are listed. Examples of water-dispersible polymers include polyurethane resins, polyurethane polyurea resins, acrylic resins, methacrylic resins, phenol resins, urea resins, and melamine resins. , Polystyrene resin, polyacetal resin, and polycarbonate resin. These aqueous polymers are used in one kind or a mixture of two or more kinds.

  The preferable content of the aqueous polymer component is 0.001 to 10% by mass. If the content of the aqueous polymer component is less than the lower limit, a sufficient use effect may not be obtained, and if the content of the aqueous polymer component is more than the upper limit, a sufficient polishing rate may not be obtained. Moreover, the preferable number average molecular weight (GPC measurement, standard polystyrene conversion) of water-soluble polymer changes with kinds, and there exists an appropriate value, respectively.

  One suitable water-soluble polymer contained in the CMP polishing composition of the present invention is polyvinylpyrrolidone, polyvinylpyrrolidone and 1-butene copolymer. These have the effect of suppressing barrier layer polishing compared to other water-soluble polymers, and have the advantage of improving the selective polishing properties of copper. Also, the effect of improving the dispersion stability of the abrasive grains is great. The preferable content of these polyvinyl pyrrolidone or polyvinyl pyrrolidone and 1-butene copolymer in the polishing composition for CMP of the present invention is 0.001 to 5% by mass, which is effective for suppressing polishing of the barrier layer. Moreover, as a number average molecular weight, 5000-100000 are preferable.

  One of the water-soluble polymers suitable for the CMP polishing composition of the present invention is polyalkylene glycols. Polyalkylene glycol exhibits an excellent polishing rate as compared with other water-soluble polymers, and has a large effect of improving the dispersion stability of abrasive grains. The preferable content of the polyalkylene glycols in the polishing composition for CMP of the present invention is 0.001 to 5% by mass, which is effective for suppressing the polishing of the barrier layer. The number average molecular weight of the polyalkylene glycol is preferably 200 to 3000.

  One of the water-dispersible polymers suitable for use in the polishing composition for CMP of the present invention is a polyurethane resin or a polyurethane polyurea resin. These are effective as an auxiliary agent for the abrasive grains and the abrasive grains because they enhance the selective polishability or the nonselective polishability with respect to the selective polishability. The polyurethane resin or the polyurethane polyurea resin is preferably self-emulsifying because the emulsifier for dispersing the polyurethane resin may affect the CMP performance.

  A cationic water-dispersed polyurethane having a cationic group introduced therein has a strong etching action on copper and may be difficult to control. Therefore, nonionic water-dispersed polyurethane or anionic water-dispersed polyurethane is more preferable. Anionic water-dispersed polyurethane is more preferred because of its high polishing rate. In the case of an anionic water-dispersed polyurethane, the acid value (mgKOH / g) is preferably 1 to 200, more preferably 10 to 150.

  The average particle size of the water-dispersed polyurethane is preferably 5 to 200 nm, more preferably 10 to 150 nm, which functions as abrasive grains and can be stably dispersed in the CMP polishing composition. The preferable content of these resins in the polishing composition for CMP of the present invention is 0.01 to 10% by mass.

  The polishing composition for CMP of the present invention may be used acidic or basic so that the oxidizing agent functions, and a pH adjuster may be used for this purpose.

  Examples of the pH adjuster component used in the polishing composition for CMP of the present invention include a water-soluble basic compound and a water-soluble acidic compound. Examples of water-soluble basic compounds include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, alkaline earth metals such as calcium hydroxide, strontium hydroxide and barium hydroxide, ammonium carbonate Alkali metal carbonates such as lithium carbonate, sodium carbonate and potassium carbonate, quaternary ammonium hydroxides such as tetramethylammonium hydroxide and choline, organic amines such as ethylamine, diethylamine, triethylamine and hydroxyethylamine, and ammonia These are used in one kind or a mixture of two or more kinds. Of these, ammonia and alkali metal hydroxides are preferred because they are inexpensive and easy to handle.

  Examples of the water-soluble acidic compound include water-soluble compounds exemplified by organic acids, and inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid.

  The pH of the polishing composition for CMP of the present invention is preferably 8-12. If the pH is less than 8 and 6 or more, a sufficient polishing rate may not be obtained. On the other hand, when the pH is less than 6, the barrier layer is polished, and the selective polishing property may be lowered. Moreover, if pH is larger than 12, dishing will occur and the surface state may deteriorate.

  The polishing composition for CMP of the present invention may contain a surfactant in order to impart polishing suppression, dissolution or dispersion stability of each component, antifoaming property, and the like. Examples of the surfactant to be contained include nonionic surfactants, anionic surfactants, cationic surfactants, and betaine surfactants, which are used in one kind or a mixture of two or more kinds. .

  The preferable content when using the surfactant component in the polishing composition for CMP of the present invention is 0.0001 to 10% by mass. If the content of the surfactant component is less than the lower limit, a sufficient use effect may not be obtained, and if the content of the surfactant component is higher than the upper limit, the polishing rate may be reduced.

  Suitable as the surfactant contained in the CMP polishing composition of the present invention is an anionic surfactant. Examples of the anionic surfactant include higher fatty acid salts, higher alcohol sulfate esters, sulfurized olefin salts, higher alkyl sulfonates, α-olefin sulfonates, sulfated fatty acid salts, sulfonated fatty acid salts, and phosphate esters. Salt, sulfate ester of fatty acid ester, glyceride sulfate ester salt, sulfonate salt of fatty acid ester, α-sulfo fatty acid methyl ester salt, polyoxyalkylene alkyl ether sulfate ester salt, polyoxyalkylene alkyl phenyl ether sulfate ester salt, polyoxy Alkylene alkyl ether carboxylates, acylated peptides, sulfate esters of fatty acid alkanolamides or alkylene oxide adducts thereof, sulfosuccinates, alkylbenzene sulfonates, alkylnaphthalene sulfones Sulfonate, alkyl benzimidazole sulfonate, polyoxyalkylene sulfosuccinate, N-acyl-N-methyltaurine salt, N-acyl glutamic acid or salt thereof, acyloxyethane sulfonate, alkoxy ethane sulfonate, N -Acyl-β-alanine or salts thereof, N-acyl-N-carboxyethyltaurine or salts thereof, N-acyl-N-carboxymethylglycine or salts thereof, acyl lactates, N-acyl sarcosine salts, and alkyl or alkenyl Mention may be made of one kind or a mixture of two or more kinds such as aminocarboxymethyl sulfate.

  The CMP polishing composition of the present invention may contain a metal eluent component that elutes the polished metal. For example, in the case of CMP of copper, examples of the metal (copper) eluent contained include ammonium salts and alkali metal salts of organic acids exemplified as the organic acid component, and these include one kind or two or more kinds. Used in a mixture.

  A preferable content when using the copper eluent is 0.01 to 10% by mass. If the copper eluent content is less than the lower limit, a sufficient polishing rate may not be obtained, and if the copper eluent content is higher than the upper limit, excessive etching may not be controlled.

  Also suitable as the copper eluent is an ammonium salt of an aliphatic organic carboxylic acid, particularly oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, fumaric acid, oxalic acid, Preference is given to ammonium salts of malic acid, tartaric acid and citric acid. When using these, the compounding quantity in the polishing composition for CMP is preferably 0.05 to 2% by mass, and more preferably 0.1 to 1% by mass.

  The polishing composition for CMP of the present invention may contain a solubilizer component in order to stably dissolve the organic component described above. Examples of solubilizers include alcohols such as methanol and ethanol; ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether, tetrahydrofuran and dioxane; alkylene glycol mono such as ethylene glycol monomethyl ether and ethylene glycol monobutyl ether Alkyl ethers; polyalcohols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, glycerin, pentaerythritol, dipentaerythritol, tetramethylolpropane; Examples include pyrrolidones such as N-methylpyrrolidone, and these are used in one kind or a mixture of two or more kinds.

  When using a solubilizer, the preferable content in the polishing composition for CMP is 0.01 to 10% by mass. When the content of the solubilizer is less than the lower limit, a sufficient use effect may not be obtained. When the content of the solubilizer is higher than the upper limit, the surface of the polished surface may be roughened.

  The polishing composition for CMP of the present invention may contain other additive components as necessary in addition to those exemplified above. As an additive component, a pH buffer; an inclusion compound such as α-, β-, or γ-cyclodextrin that includes an organic compound effective to reduce organic contamination of the wafer; imparts surface smoothness to the polished surface Hydroxyalkanesulfonic acid fatty acid esters such as isethionic acid fatty acid esters; monoethanolamine, diethanolamine, triethanolamine, 2 which improve the dispersion stability and polishing ability of the abrasive grains by imparting a cleaning action on the abrasive grain surface -Alkanolamines such as dimethylaminoethanol, 2- (2-aminoethylamino) ethanol, N-methyldiethanolamine and the like. When these other additive components are used, they are blended in the polishing composition for CMP in a range of 0.0001 to 10% by mass, preferably 0.0005 to 5% by mass, respectively.

  The polishing composition for CMP of the present invention comprises the above-described components in the above-described contents, but the rest is water. Therefore, water is added to make the whole 100 mass% so as to obtain a polishing composition for CMP containing the above-mentioned components in prescribed amounts.

  Preparation of the polishing composition for CMP of this invention should just mix each component demonstrated above and water, and should disperse and dissolve uniformly. When using a water-soluble polymer or a water-dispersible polymer, these may be added in the form of a composition previously dissolved or dispersed in water. In addition, the CMP polishing composition of the present invention may be a one-component type composition by mixing all components, or a two-component type composition. Examples of the two-component type composition include a two-component type in which only the oxidizing agent component is a separate component and a mixture of all other components. When a peroxide is used as the oxidizing agent, it is usually a two-component type composition.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited by the following examples. In the text, “part” or “%” is based on mass unless otherwise specified.

[Production Example 1] Production of surface modifier compounds a to q As a silane coupling agent having an isocyanate group, 3-isocyanatopropyltrimethoxysilane is used, and as a hydroxy compound having EO or EO and PO, a diol compound Alternatively, an alcohol compound is used, and the molar ratio of hydroxyl group to isocyanate group is blended at a ratio of OH: NCO = 1.1: 1 and stirred at 100 ° C. for 2 hours, and then tetraisopropoxy titanium is added to the total mass of the raw material. 0.005% was added and further stirred at 100 ° C. for 2 hours to obtain various surface modifier compounds. The completion of the reaction was confirmed by disappearance of the isocyanate group using IR. The obtained surface modifier compounds are shown in Tables 1 and 2. In addition, although m, p, and n of the said General formula (6) and General formula (7) are shown in a table | surface, this is the value computed from the molecular weight of the diol compound and alcohol compound which are raw materials.

[Production Example 2] Production of surface modifier compounds r and s As a silane coupling agent having an amino group, 3-aminopropyltrimethoxysilane is used, and as a hydroxy compound having EO, acrylic at the end of a polyethylene glycol chain. NK ester A-600 with groups was used. The molar ratio of acrylic group to amino group was blended at a ratio of 1.2: 1, and the mixture was stirred at 60 ° C. for 5 hours to obtain surface modifier compound r. The completion of the reaction was confirmed by disappearance of the starting material 3-aminopropyltrimethoxysilane using gas chromatography. The obtained surface modifier compound r is of the general formula (10) type, and m + p = 13 (calculated value) and n = 0 (calculated value).

  Further, 3- [methoxypoly (ethyleneoxy)] propyltrimethoxysilane was used as the surface modifier compound s. m + p = 6 to 9 (calculated value) and n = 0 (calculated value).

[Examples 1 to 5] Surface-modified colloidal silica No. 1 1-No. 5: Average particle diameter obtained by the hydrolysis method of tetraethoxysilane: 120.6 nm, particle size distribution: cumulative 10% value; 95.3 nm, cumulative 50% value; 117.4 nm, cumulative 90% value; 5 nm colloidal silica dispersion (hereinafter referred to as colloidal silica A before surface modification, 10% silicon dioxide content) was heated to 60 ° C., and each of the surface modifier compounds a to e obtained in the above production examples. A mixed solution of 10 parts, 50 parts of water and 1 part of a 0.1 mol / liter nitric acid aqueous solution was added dropwise. The amount of dripping is 3 parts of the surface modifier compound with respect to 100 parts of silicon dioxide of colloidal silica. After the dropwise addition, the mixture was stirred at 60 ° C. for 2 hours to obtain surface modified colloidal silica No. 1-5 were obtained. About each obtained surface modification colloidal silica, X-ray photoelectron spectroscopy (XPS) analysis was performed and surface modification was confirmed compared with colloidal silica A before surface modification. The particle size distribution was measured with a laser diffraction particle size analyzer.

[Examples 6 to 13] Surface-modified colloidal silica No. 6 6-No. Production of No. 13 Obtained by the hydrolysis method of tetraethoxysilane, average particle size: 155.9 nm, particle size distribution: cumulative 10% value; 114.3 nm, cumulative 50% value; 153.7 nm, cumulative 90% value; 6 nm colloidal silica dispersion (hereinafter referred to as pre-surface-modified colloidal silica B, 10% silicon dioxide content) was heated to 60 ° C., and surface modifier compounds b, i, j obtained in the above production examples were used. A mixed solution of 10 parts of ~ p, 50 parts of water and 1 part of a 0.1 mol / liter nitric acid aqueous solution was added dropwise. The amount of dripping is 10 parts of the surface modifier compound with respect to 100 parts of silicon dioxide of colloidal silica. After the dropwise addition, the mixture was stirred at 60 ° C. for 2 hours to obtain surface modified colloidal silica No. 6-13 were obtained. About each obtained surface modification colloidal silica, the particle size distribution was measured by the X-ray photoelectron spectroscopy (XPS) analysis and the laser diffraction type particle size analyzer similarly to the said Example.

(Result of XPS analysis)
About surface modification colloidal silica, all of Examples 1-13 brought the following results.
(1) A CO-derived peak was confirmed at 282.8 eV of carbon atoms. This peak is not observed in colloidal silica before surface modification.
(2) Oxygen atom A peak of 530.6 eV was confirmed. The colloidal silica before the surface modification was 531.0 eV, and a chemical shift due to bonding was confirmed.
(3) Nitrogen atom A peak of 398.0 eV was confirmed. This peak is not confirmed in the colloidal silica before the surface modification.
(4) Silicon atom A peak of 101.0 eV was confirmed. The colloidal silica before the surface modification was 101.7 eV, and a chemical shift due to bonding was observed.

[Example 14] Surface modified colloidal silica no. 14 The above Examples 1 to 5 except that the surface modifier compound c was used as the surface modifier compound and the amount of the surface modifier compound used was 1 part with respect to 100 parts of silicon dioxide of colloidal silica. In the same manner, the surface-modified colloidal silica No. 14 was obtained.

[Example 15] Surface modified colloidal silica no. Production of 15 The above Examples 1 to 5 except that the surface modifier compound c was used as the surface modifier compound and the amount of the surface modifier compound used was 10 parts relative to 100 parts of silicon dioxide of colloidal silica. In the same manner, the surface-modified colloidal silica No. 15 was obtained.

[Comparative Example 1] Production of surface-modified colloidal silica comparative 1 Methyltriethoxysilane was used as the surface modifier compound, 10 parts of the surface modifier compound, 50 parts of water, 0.1 mol / liter nitric acid aqueous solution Was added dropwise to a dispersion of colloidal silica B heated to 60 ° C. The amount of methyltriethoxysilane used is 4 parts per 100 parts of colloidal silica silicon dioxide. Except this, surface-modified colloidal silica comparison 1 was obtained in the same manner as in Examples 6 to 13 above.

[Comparative Example 2] Production of surface-modified colloidal silica comparative 2 The same method as in Comparative Example 1 except that the amount of methyltriethoxysilane used was 10 parts with respect to 100 parts of silicon dioxide of colloidal silica. The surface-modified colloidal silica comparison 2 was obtained.

[Examples 16 to 24] Polishing composition Nos. 1-No. 9 Preparation of surface modified colloidal silica 1% described in Table 5, ammonium persulfate 1.5%, glycine 1%, benzotriazole 0.001%, dodecylbenzenesulfonic acid 0.02%, potassium hydroxide 0.3% And a polishing composition No. for CMP comprising water (residue). 1-No. 9 was obtained.

[Comparative Example 4] Production of polishing composition for comparison 1 for CMP Colloidal silica B 1% before surface modification, ammonium persulfate 1.5%, glycine 1%, benzotriazole 0.001%, dodecylbenzenesulfonic acid 0.02% A polishing composition for CMP comparison 1 comprising 0.3% potassium hydroxide and water (residue) was obtained.

[Comparative Example 5] Production of CMP polishing composition comparison 2 Colloidal silica B 1% before surface modification, ammonium persulfate 1.5%, glycine 1%, benzotriazole 0.001%, dodecylbenzenesulfonic acid 0.02% A polishing polishing composition for CMP 2 comprising 0.3% potassium hydroxide, 0.1% polyethylene glycol monomethyl ether (MePEG400) having a number average molecular weight of 400 and water (residue) was obtained.

[Comparative Example 6] Production of polishing composition for comparison 3 for CMP 1% surface-modified colloidal silica 1%, 1.5% ammonium persulfate, 1% glycine, 0.001% benzotriazole, 0. 1% dodecylbenzenesulfonic acid A polishing composition for CMP comparison 3 comprising 02%, potassium hydroxide 0.3% and water (residue) was obtained.

[Comparative Example 7] Manufacture of polishing composition for comparison 4 for CMP 1% of surface-modified colloidal silica, 1.5% of ammonium persulfate, 1% of glycine, 0.001% of benzotriazole, 0. 1% of dodecylbenzenesulfonic acid A polishing composition composition for CMP 4 comprising 02%, potassium hydroxide 0.3% and water (residue) was obtained.

[Evaluation Example 1]
Polishing composition No. for CMP of Table 5 above. 1-No. 7. For Comparative Example 1 and Comparative Example 2, a copper blanket test piece obtained by cutting a copper film of 1500 nm on a silicon substrate by electrolytic plating to a 3 cm × 3 cm square and 200 nm of tantalum on the silicon substrate by sputtering. Using a tantalum blanket test piece obtained by cutting a film-formed wafer into 3 cm × 3 cm squares, the polishing rate was evaluated under the following polishing conditions. The results are shown in Table 6. The polishing amount was measured from the difference in film thickness before and after polishing using Loresta GP (manufactured by Mitsubishi Chemical).
Polishing machine: NF-300 (manufactured by Nano Factor)
Polishing pad: IC1400 (with XY groove) (Rohm and Haas)
Polishing time: 1 minute Surface plate rotation speed: 60 rpm
Carrier rotation speed: 60rpm
Polishing pressure: 2 psi
Polishing liquid supply rate: 35 ml / min

  From Table 6 above, polishing composition Nos. For CMP using the surface-modified colloidal silica of the present invention as abrasive grains were used. 1-No. No. 7 showed a good polishing rate for copper, and it was confirmed that polishing was suppressed for tantalum. On the other hand, polishing composition No. 1 for CMP using colloidal silica not surface-modified and polishing composition No. 1 for CMP using colloidal silica not surface-modified. The surface modified colloidal silica No. 4 used in No. 4 was used. In Comparative Example 2 in which MePEG400 corresponding to 10 surface modifying group equivalents was added separately, polishing suppression against tantalum was insufficient. From this, it can confirm that the improvement of the selective polishing property with respect to copper is the effect by the surface modification | reformation of the colloidal silica which is an abrasive grain.

[Examples 25 to 27] Polishing composition No. 10-No. Production of 12 Surface modified colloidal silica 1% described in Table 7, 1.5% ammonium persulfate, 1% glycine, 0.001% benzotriazole, 0.02% dodecylbenzenesulfonic acid, polyvinylpyrrolidone and number average molecular weight 17000 1-butene copolymer (P-904LC; manufactured by ISP) 0.03%, potassium hydroxide 0.3% and water (residue). 10-No. 12 was obtained.

[Comparative Example 8] Production of CMP polishing composition comparative sample 5 The same composition as in Examples 25 to 27 except that 1 part of pre-surface-modified colloidal silica was used instead of 1% of surface-modified colloidal silica. A polishing composition comparative sample 5 for CMP was obtained.

[Evaluation Example 2]
With respect to the polishing composition for CMP described in Table 7 above, evaluation of the polishing rate as a copper blanket 8-inch wafer polished body in which a copper film was formed to 1500 nm on a silicon substrate by electrolytic plating, and tetrakisethoxysilane was used. After forming a hard silica layer of 250 nm deep and 50 μm wide on the hard silica layer of the wafer on which the hard silica film was formed by plasma CVD method with a space of 50 μm, a tantalum / tantalum nitride film was formed at 15 nm / 15 nm by sputtering. After depositing and depositing a 100 nm copper seed layer by sputtering, dishing evaluation and copper polishing residual evaluation were performed using a patterned 8-inch wafer on which a copper film of 1000 nm was formed by electrolytic plating.

  The polishing conditions are as follows. The polishing rate was measured from the difference in film thickness before and after polishing using Loresta GP (manufactured by Mitsubishi Chemical). Dishing was measured using an atomic force microscope (AFM) Nanopics (manufactured by Seiko Instruments Inc.) at the step of the 50 μm copper wiring portion. The copper polishing residue was checked with an optical microscope for the presence of a copper residual film when 20% overpolishing (overpolishing). The results are shown in Table 8.

Polishing machine: AVANTI472 (manufactured by IPEC)
Polishing pad: IC1400 (with XY groove) (Rohm and Haas)
Polishing time: 1 minute Surface plate rotation speed: 93 rpm
Carrier rotation speed: 87rpm
Polishing pressure: 2 psi
Polishing liquid supply rate: 200 ml / min

  From Table 8 above, polishing composition Nos. For CMP using the surface-modified colloidal silica of the present invention as abrasive grains were used. 10-No. No. 12 has been confirmed to have an effect of suppressing copper polishing residue. The effect of suppressing the copper polishing residue increases as the degree of surface modification of the colloidal silica used increases. On the other hand, it was also confirmed that the dishing was less effective as the degree of surface modification of the colloidal silica was increased. It turns out that the polishing composition for CMP which does not have a copper grinding | polishing residue can be provided, suppressing dishing with the surface modification amount of surface modification colloidal silica.

[Examples 28 to 30] Polishing composition No. 13-No. 15: Surface modified colloidal silica 1% listed in Table 9, 1.5% ammonium persulfate, 1% glycine, 0.001% benzotriazole, 0.02% dodecylbenzenesulfonic acid, polyvinylpyrrolidone and number average molecular weight 17000 1-butene copolymer (P-904LC; manufactured by ISP) 0.03%, potassium hydroxide 0.3% and water (residue). 13-No. 15 was obtained.

[Evaluation Example 3]
Regarding the polishing composition for CMP described in Table 9 above, a copper blanket 8-inch wafer in which a copper film was formed on a silicon substrate by an electrolytic plating method with a thickness of 1500 nm, and a tantalum blanket 8 in which a tantalum film was formed on a silicon substrate by a sputtering method. Evaluation of polishing rate using inch wafer as the object to be polished, and 500nm deep and 50μm wide groove on the hard silica layer of 500nm hard silica film formed by plasma CVD method using tetrakisethoxysilane space of 50μm After forming a tantalum film, a tantalum film having a thickness of 25 nm is deposited by sputtering, a copper seed layer having a thickness of 100 nm is further deposited by sputtering, and then an 8-inch wafer having a copper film having a thickness of 1000 nm formed by electrolytic plating is used as a dishing dish. Evaluation and copper polishing residual evaluation were performed.

  The polishing conditions are as follows. The polishing rate was measured from the difference in film thickness before and after polishing using Loresta GP (manufactured by Mitsubishi Chemical). Dishing was measured using an atomic force microscope (AFM) Nanopics (manufactured by Seiko Instruments Inc.) at the step of the 50 μm copper wiring portion. Regarding the copper polishing residue, the presence or absence of a copper residual film was confirmed with an optical microscope when copper was overpolished by 20%. The results are shown in Table 10.

Polishing machine: AVANTI472 (manufactured by IPEC)
Polishing pad: IC1400 (with XY groove) (Rohm and Haas)
Polishing time: 1 minute Surface plate rotation speed: 93 rpm
Carrier rotation speed: 87rpm
Polishing pressure: 2 psi
Polishing liquid supply rate: 200 ml / min

  From Table 10 above, the polishing composition No. 1 for CMP using the surface-modified colloidal silica of the present invention as abrasive grains was used. 13-No. No. 15 has been confirmed to have an effect of suppressing copper polishing residue. It was also confirmed that the effect of suppressing the copper polishing residue was better as the molecular weight of polyethylene glycol used as a raw material for the surface modifier of the colloidal silica used was smaller. It can be seen that a polishing composition for CMP that does not have a copper polishing residue can be provided while suppressing dishing by the molecular weight of the polyether chain of the surface modifier of the surface-modified colloidal silica.

[Evaluation Example 4]
Polishing evaluation similar to the evaluation example 3 was performed on the polishing composition comparison samples 3 and 4 obtained in Comparative Examples 6 and 7. The results are shown in Table 11.

  From Table 11 above, the polishing composition for CMP comparison 3 and the comparison 4 using colloidal silica surface-modified with methyltriethoxysilane have no effect of suppressing copper polishing residue, and the surface modification of colloidal silica. There is no correlation between the degree and the dishing suppression effect. In addition, it was confirmed that the polishing rate of copper greatly decreased as the degree of surface modification of colloidal silica increased. It can be seen that the effect of use is different from the surface-modified colloidal silica of the present invention.

[Examples 31 to 38] Surface-modified colloidal silica No. 16-No. The average particle size obtained by the hydrolysis method of tetraethoxysilane; 120.6 nm, particle size distribution: cumulative 10% value; 84.7 nm, cumulative 50% value; 112.7 nm, cumulative 90% value; A dispersion of 0 nm colloidal silica (hereinafter referred to as colloidal silica C before surface modification, 10% silicon dioxide content) was heated to 60 ° C., and each of the surface modifier compounds a to h obtained in the above production examples A mixed solution of 10 parts, 50 parts of water and 1 part of a 0.1 mol / liter nitric acid aqueous solution was added dropwise. The amount of dripping is 3 parts of the surface modifier compound with respect to 100 parts of silicon dioxide of colloidal silica. After the dropwise addition, the mixture was stirred at 60 ° C. for 2 hours to obtain surface modified colloidal silica No. 16-23 were obtained. About each obtained surface modification colloidal silica, the X-ray photoelectron spectroscopy (XPS) analysis was performed like Examples 1-13, and surface modification was confirmed compared with the colloidal silica C before surface modification.

[Examples 39 to 46] Polishing composition Nos. 16-No. Production of No. 23 Polishing composition No. for CMP comprising 1% surface-modified colloidal silica described in Table 12, 1.5% ammonium persulfate, 0.3% ammonium sulfate, 0.4% potassium hydroxide and water (residue) . 16-No. 23 was obtained.

[Comparative Example 9] Production of polishing composition for comparison for CMP 6 Colloidal silica C1% before surface modification, 1.5% ammonium persulfate, 0.3% ammonium sulfate, 0.4% potassium hydroxide and water (residue) A polishing composition for CMP 6 for comparison was obtained.

[Evaluation Example 5]
Polishing composition Nos. For CMP described in Table 12 above. 16-No. 23 and Comparative Example 6, a copper blanket test piece obtained by cutting a wafer having a copper film of 1500 nm formed on a silicon substrate by an electrolytic plating method into a 3 cm × 3 cm square, and a tantalum film of 150 nm formed on a silicon substrate by a sputtering method Using a tantalum blanket test piece obtained by cutting a wafer into a 3 cm × 3 cm square as an object to be polished, the polishing rate was evaluated under the following polishing conditions. The results are shown in Table 13. The polishing amount was measured from the difference in film thickness before and after polishing using Loresta GP (manufactured by Mitsubishi Chemical).
Polishing machine: NF-300 (manufactured by Nano Factor)
Polishing pad: IC1000 (with XY groove) (Rohm and Haas)
Polishing time: 2 minutes Surface plate rotation speed: 60 rpm
Carrier rotation speed: 60rpm
Polishing pressure: 3 psi
Polishing liquid supply rate: 30 ml / min

  From Table 13 above, there was a tendency that as the molecular weight of polyethylene glycol used as the raw material for the surface modifier of the colloidal silica used increased, the copper polishing rate decreased slightly while the tantalum polishing rate decreased significantly. . That is, it was confirmed that the higher the molecular weight of the surface modifier compound, the better the copper / tantalum polishing selectivity.

[Examples 47 and 48] Surface-modified colloidal silica no. 24, no. In the same manner as in Examples 31 to 38, the surface modified colloidal silica No. 25 was prepared by using the surface modifier compounds q and s as the surface modifier compounds, respectively. 24, no. 25 was obtained.

[Example 49] Surface modified colloidal silica no. Production of No. 26 A dispersion of colloidal silica C using a surface modifier compound r as a surface modifier compound, and heating a mixed solution comprising 10 parts of the surface modifier compound r and 50 parts of water to 60 ° C. It was dripped in. The amount of dripping is 3 parts of the surface modifier compound with respect to 100 parts of silicon dioxide of colloidal silica. After the dropwise addition, the mixture was stirred at 60 ° C. for 2 hours, and surface-modified colloidal silica no. 26 was obtained.

[Examples 50 to 52] Polishing composition No. 24-No. 26 No. 26 above. 24-26 surface-modified colloidal silica 1%, ammonium persulfate 1.5%, glycine 1%, benzotriazole 0.001%, dodecylbenzenesulfonic acid 0.02%, polyvinylpyrrolidone and 1-butene having a number average molecular weight of 17,000 Polishing composition No. for CMP (P-904LC; made by ISP) 0.03%, potassium hydroxide 0.3% and water (residue). 24-No. 26 was obtained.

[Comparative Example 10] Production of polishing composition for comparison 7 for CMP Colloidal silica C 1% before surface modification, 1.5% ammonium persulfate, 1% glycine, 0.001% benzotriazole, 0.02% dodecylbenzenesulfonic acid Polishing composition for CMP, comprising 0.03% of a copolymer of polyvinylpyrrolidone and 1-butene having a number average molecular weight of 17000 (P-904LC; manufactured by ISP), 0.3% of potassium hydroxide and water (residue) Comparative 7 was obtained.

[Evaluation Example 6]
Regarding the polishing compositions for CMP of Examples 50 to 52 and Comparative Example 10 described above, a copper blanket 8-inch wafer in which a copper film was formed on a silicon substrate by an electrolytic plating method to a thickness of 1500 nm, and tantalum 150 nm was formed on the silicon substrate by a sputtering method. Evaluation of polishing speed using a coated tantalum blanket 8-inch wafer as an object to be polished and a hard silica layer of 500 nm in thickness and 50 μm in width on the hard silica layer of the wafer formed by plasma CVD using tetrakisethoxysilane. After forming a groove with a space of 50 μm, a tantalum film having a thickness of 25 nm is deposited by sputtering, a copper seed layer having a thickness of 100 nm is deposited by sputtering, and then an 8-inch wafer on which a 1000 nm copper film is formed by electrolytic plating is covered. Evaluation of dishing and polished copper as a polished body The price was done.

  The polishing conditions are as follows. The polishing rate was measured from the difference in film thickness before and after polishing using Loresta GP (manufactured by Mitsubishi Chemical). Dishing was measured using an atomic force microscope (AFM) Nanopics (manufactured by Seiko Instruments Inc.) at the step of the 50 μm copper wiring portion. Regarding the copper polishing residue, the presence or absence of a copper remaining film when copper was overpolished by 40% was confirmed with an optical microscope. The results are shown in Table 14.

Polishing machine: AVANTI472 (manufactured by IPEC)
Polishing pad: IC1400 (with XY groove) (Rohm and Haas)
Polishing time: 1 minute Surface plate rotation speed: 93 rpm
Carrier rotation speed: 87rpm
Polishing pressure: 2 psi
Polishing liquid supply rate: 200 ml / min

  From Table 14 above, polishing composition Nos. For CMP using the surface-modified colloidal silica of the present invention as abrasive grains were used. 24-No. No. 26 has been confirmed to have an effect of suppressing copper polishing residue. From this, it was found that the polyethylene glycol structure of the surface modifier compound contributes to the suppression effect of the copper polishing residue. In addition, the polishing composition no. 24-No. No. 26 could be polished without greatly losing flatness.

[Comparative Example 11] Production of surface-modified colloidal silica comparative 3 Glycidopropyltriethoxysilane was used as the surface modifier compound, the surface modifier compound was 10 parts, water was 50 parts, and 0.1 mol / liter. A mixed solution composed of 5 parts of an aqueous nitric acid solution was dropped into a dispersion of colloidal silica C heated to 60 ° C. The amount of glycidpropyltriethoxysilane used is 3 parts per 100 parts of colloidal silica silicon dioxide. After dropping, the mixture was stirred at 60 ° C. for 2 hours to obtain surface-modified colloidal silica comparison 3.

[Comparative Example 12] Production of surface-modified colloidal silica comparative 4 3-ureidopropyltriethoxysilane was used as the surface modifier compound, the surface modifier compound was 10 parts, water was 50 parts, 0.1 mol / A mixed solution consisting of 1 part of a liter nitric acid aqueous solution was dropped into a dispersion of colloidal silica C heated to 60 ° C. The amount of 3-ureidopropyltriethoxysilane used is 3 parts per 100 parts of colloidal silica silicon dioxide. After dropping, the mixture was stirred at 60 ° C. for 2 hours to obtain surface-modified colloidal silica comparison 4.

[Comparative Example 13] Production of surface-modified colloidal silica comparative 5 (3-mercaptopropyl) triethoxysilane was used as the surface modifier compound, the surface modifier compound was 10 parts, water was 50 parts, 0.1 A mixed solution consisting of 2 parts of a mol / liter nitric acid aqueous solution was dropped into a dispersion of colloidal silica C heated to 60 ° C. The amount of (3-mercaptopropyl) triethoxysilane used is 3 parts with respect to 100 parts of silicon dioxide of colloidal silica. After dropping, the mixture was stirred at 60 ° C. for 2 hours to obtain surface-modified colloidal silica comparison 5.

[Comparative Examples 14 to 16] Production of CMP polishing compositions for comparison 8 to 10 Surface-modified colloidal silica 1%, ammonium persulfate 1.5%, glycine 1%, benzotriazole 0.001 of Comparative Examples 11 to 13 above %, Dodecylbenzenesulfonic acid 0.02%, polyvinylpyrrolidone and 1-butene copolymer having a number average molecular weight of 17,000 (P-904LC; manufactured by ISP) 0.03%, potassium hydroxide 0.3% and water ( 8 to 10 for comparison with polishing compositions for CMP consisting of the remainder).

[Evaluation Example 7]
Regarding the polishing compositions for CMP of Comparative Examples 14 to 16, a copper blanket 8-inch wafer in which a copper film was formed on a silicon substrate by an electrolytic plating method with a thickness of 1500 nm, and a tantalum blanket in which a tantalum 150 nm film was formed on a silicon substrate by a sputtering method. Evaluation of polishing rate using an 8-inch wafer as an object to be polished, and a hard silica layer of 500 nm in thickness formed by a plasma CVD method using tetrakisethoxysilane on a hard silica layer of a wafer having a depth of 500 nm and a width of 50 μm is 50 μm. After creating a space, a tantalum film having a thickness of 25 nm was deposited by a sputtering method, a copper seed layer having a thickness of 100 nm was deposited by sputtering, and then an 8-inch wafer having a copper film having a thickness of 1000 nm formed by an electrolytic plating method was used as a polishing target. Dishing evaluation and copper polishing residual evaluation were performed.

  The polishing conditions are as follows. The polishing rate was measured from the difference in film thickness before and after polishing using Loresta GP (manufactured by Mitsubishi Chemical). Dishing was measured using an atomic force microscope (AFM) Nanopics (manufactured by Seiko Instruments Inc.) at the step of the 50 μm copper wiring portion. Regarding the copper polishing residue, the presence or absence of a copper remaining film when copper was overpolished by 40% was confirmed with an optical microscope. The results are shown in Table 15.

Polishing machine: AVANTI472 (manufactured by IPEC)
Polishing pad: IC1400 (with XY groove) (Rohm and Haas)
Polishing time: 1 minute Surface plate rotation speed: 93 rpm
Carrier rotation speed: 87rpm
Polishing pressure: 2 psi
Polishing liquid supply rate: 200 ml / min

  From Table 15 above, the polishing composition for CMP comparison 8 using colloidal silica surface-modified with glycidpropyl propyltriethoxysilane has no dishing suppression effect, and after polishing by the CMP polishing composition comparison 8 It turns out that flatness was also bad. Moreover, although the polishing composition comparison 9 for CMP using the colloidal silica surface-modified with 3-ureidopropyltriethoxysilane showed the polishing suppression with respect to tantalum, the suppression effect with respect to the copper polishing residue was not seen. . The polishing composition for CMP comparison 10 using colloidal silica surface-modified with (3-mercaptopropyl) triethoxysilane showed polishing suppression for tantalum but did not show a sufficient polishing rate for copper.

[Example 53] Surface modified colloidal silica no. Production of No. 27 The same as in Examples 1 to 5, except that the surface modifier compound b was used as the surface modifier compound and the amount of the surface modifier compound used was 7 parts relative to 100 parts of silicon dioxide in colloidal silica. Surface modified colloidal silica no. 27 was obtained.

[Examples 54 to 58] Polishing composition Nos. 28-No. No. 32 above. 25-No. 27 surface modified colloidal silica 6.5%, hydrogen peroxide 1%, benzotriazole 0.02%, dodecylbenzenesulfonic acid 0.02%, potassium bicarbonate 0.1%, potassium hydroxide 1.2%, Polishing composition No. for CMP which consists of 0.1% of polyethylene glycol (PEG400) and water (residue). 28-No. 32 was obtained.

[Comparative Example 17] Production of CMP polishing composition for comparison 11 Colloidal silica A 6.5% before surface modification, hydrogen peroxide 1%, benzotriazole 0.02%, dodecylbenzenesulfonic acid 0.02%, hydrogen carbonate A comparative polishing composition for CMP 11 comprising 0.1% potassium, 1.2% potassium hydroxide, 0.1% polyethylene glycol (PEG 400) and water (residue) was obtained.

[Evaluation Example 8]
Regarding the polishing compositions for CMP of Examples 54 to 58 and Comparative Example 17 described above, a copper blanket 8-inch wafer in which a copper film was formed on a silicon substrate by an electrolytic plating method to a thickness of 1500 nm, and tantalum 150 nm was formed on the silicon substrate by a sputtering method. A tantalum blanket 8-inch wafer, a PE-TEOS blanket 8-inch wafer with PE-TEOS 800 nm deposited on a silicon substrate by plasma CVD, and a BD1 with Black Diamond 1 (BD1) 1000 nm deposited on a silicon substrate by plasma CVD Evaluation of the polishing rate using a blanket 8-inch wafer as an object to be polished and fang evaluation using an 854 pattern wafer including a 450 nm BD1 insulating film from which the plated copper film was removed under the same conditions as the object to be polished were performed.

  The polishing conditions are as follows. The polishing rate of copper film and tantalum film is Loresta GP (Mitsubishi Chemical), and the polishing rate of PE-TEOS film and BD1 film is F20-2 (FILMETRICS). Measured from The fang was confirmed with an atomic force microscope (AFM) Nanopics (manufactured by Seiko Instruments Inc.). The results are shown in Tables 16 and 17.

Polishing machine: AVANTI472 (manufactured by IPEC)
Polishing pad: IC1400 (with K groove) (Rohm and Haas)
Surface plate rotation speed: 140 rpm
Carrier rotation speed: 125rpm
Polishing pressure: 1.5 psi
Polishing liquid supply rate: 130 ml / min Blanket wafer polishing time: 1 minute Pattern wafer polishing time: Time required for polishing BD1 by 20 nm

  From Table 17 above, the fang was improved by surface modification. In addition, from Table 16 above, it was also confirmed that the polishing rate was not impaired by surface modification as compared with unmodified colloidal silica.

Claims (5)

Surface-modified colloidal silica, which is surface-modified with at least one group represented by the following general formulas (1), (2) and (3).

(In the formula, A ¹ represents a group selected from the following formulas (a11) to (a13), (a31) to (a33) and (a51) to (a53), and A ² represents the following formula (a21) to Represents a group selected from (a23), (a41) to (a43) and (a61) to (a63), R ³ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and Y represents A ² or Represents R ³ , EO represents an ethylene oxide group, PO represents a propylene oxide group, m, n, and p are m is 0 to 170, n is 0 to 120, p is 0 to 170, and m + p is Represents a non-zero number.)

(Wherein R ¹ and R ² represent an alkyl group having 1 to 4 carbon atoms, a phenyl group or a hydroxyl group, X represents an alkylene group having 1 to 18 carbon atoms, and R represents a hydrogen atom or a methyl group. To express.)   2. The surface-modified colloidal silica according to claim 1, wherein in the general formula (1), (2) or (3), m + p is a numerical value of n or more.   The surface-modified colloidal silica according to claim 2, wherein m + p is in the range of 2 to 340 in the general formula (1), (2) or (3).   A polishing composition for CMP, comprising the surface-modified colloidal silica according to claim 1.   The polishing composition for CMP according to claim 4, further comprising a persulfate.