KR100851615B1 - Chemical mechanical polishing composition - Google Patents

Abstract

The chemical and mechanical polishing compositions according to the invention comprise abrasive components, corrosion inhibitors, surfactants, discrete compounds, metal residue inhibitors and water. The metal residue inhibitor is selected from the group consisting of compounds having the formula and combinations thereof:

Wherein R ¹ , R ² , R ³ and R ⁴ are independently selected from the group consisting of H, C ₁ -C ₆ alkyl, C ₂ -C ₆ alkenyl, and C ₂ -C ₆ alkylidine; R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are independently selected from the group consisting of H and C ₁ -C ₆ alkyl.

Polishing compositions, abrasives, corrosion inhibitors, surfactants, discrete compounds, metal residue inhibitors

Description

Chemical and mechanical polishing compositions {CHEMICAL MECHANICAL POLISHING COMPOSITION}

FIELD OF THE INVENTION The present invention relates to chemical and mechanical polishing compositions, and more particularly to chemical and mechanical polishing compositions capable of preventing unwanted metal residues and dishing effects on the wafer surface.

Chemical and mechanical polishing is a technique for solving the focusing problem in the photolithography process by removing defects on the wafer surface to obtain the planarity of the surface. This chemical and mechanical polishing technique was originally used for the manufacture of microdevices having a size of less than 0.5 μm. However, with the trend toward miniaturization of devices today, chemical and mechanical polishing techniques are widely used in the industrial field.

In the process of manufacturing integrated circuits, polishing processes are used for the planarization of the metal wires used to connect the interlayers (eg, silicon oxide and silicon nitride) and active devices. The method for polishing metal wires such as tungsten, copper and aluminum includes placing a semiconductor wafer on a polishing stage equipped with a polishing head, and applying a slurry containing abrasive particles to the surface of the semiconductor wafer to improve polishing efficiency. It includes a step. Two mechanisms can be chosen to polish the metal wire using the slurry composition. In a first mechanism, the components in the slurry composition react with the metal wire to form an oxide layer continuously on the metal surface, and the abrasive particles in the slurry composition serve to polish and remove the oxide layer. The first mechanism generally requires an oxidant. In the second mechanism, no protective oxide layer is formed. Instead, the components in the slurry composition corrode and dissolve the metal, and the mechanical action of the abrasive particles speeds up the dissolution so that the thickness of the metal wire is reduced. Due to uneven polishing problems in the CMP process, unwanted dishing effects and metal residues on the wafer surface are likely to occur.

US 6,447,563 discloses a slurry system used for polishing a metal layer. The slurry system includes a first portion and a second portion, and has a pH value in the range of 2-11. The first portion comprises a dispersion solution consisting essentially of the abrasive, stabilizer and surfactant. The second part comprises an activator solution free of abrasives, which comprises an oxidizing agent, an acid, an amine, a chelating agent, a fluorine containing compound, a corrosion inhibitor, a biological material, a surfactant, a buffer, and mixtures thereof. It has two or more components selected from the group. The acid in the activator solution of the second part may be an organic acid such as formic acid, acetic acid, lactic acid or the like, or an inorganic acid such as hydrochloric acid, sulfuric acid or the like. Preferred acids are acids containing at least one carboxylic acid group substituted with a hydroxyl group, such as malic acid, tartaric acid, gluconic acid and citric acid. In addition, the surfactant may be a nonionic, anionic, cationic or zwitterionic surfactant. In an embodiment of this invention, a copper wafer was polished using a slurry system consisting of 4% by weight fumed silica, 1% by weight H ₂ O ₂ , and 0.1 mol propanoic acid. The removal rate was greater than 450 nm and the nonuniformity was less than 5%. This invention mainly focuses on the improvement of the polishing speed. The problem of metal residues on the wafer surface is not addressed in this patent.

U. S. Patent No. 6,846, 177 discloses a method for producing a metal wire contact plug of a semiconductor device by a chemical and mechanical polishing (CMP) process. The method comprises (1) 1 to 20 wt% abrasive, 0.1 to 15 wt% oxidant and 0.01 to 10 wt% complexing agent, based on gross weight, greater than 10 for a metal / insulating film. Performing a first CMP process using a first slurry solution having an etching selectivity and a pH in the range 2-9; And (2) a second slurry solution, comprising 5-30 wt% abrasive and 0.1-5 wt% oxidant, based on total weight, having an etching selectivity of less than 3 and a pH in the range of 6-12, for metal / insulating films Using a second CMP process. The complexing agent of the first slurry solution is selected from the group consisting of citric acid, tartaric acid, succinic acid, malic acid, maleic acid, fumaric acid, malonic acid, EDTA, glycolic acid, salts thereof, and mixtures thereof. This patent solves the problem of metal wire contact plugs not being easily disconnected. However, the problem caused by uneven polishing is not mentioned.

Taiwan patent application 574352 discloses a slurry composition for a chemical mechanical polishing (CMP) process and its use. The slurry composition comprises 70 to 99.5 weight percent aqueous solvent, 0.1 to 25 weight percent abrasive particles, 0.01 to 1 weight percent corrosion inhibitor, and 0.01 to 1 weight percent chemical. The chemical is selected from the group consisting of compounds having the formula and combinations thereof:

Wherein X, Y and Z are independently selected from the group consisting of H and C ₁ -C ₆ alkyl. The purpose of this reference patent is to prevent dishing of copper.

Since the components of the slurry composition for the CMP process have a great influence on the polishing rate, degree of dishing and metal residue on the wafer surface, it is desirable to provide a composition that can eliminate metal dishing and metal residue problems while maintaining the desired polishing rate. Required.

Accordingly, it is an object of the present invention to provide a chemical and mechanical polishing composition that can overcome at least one of the problems of the prior art described above.

According to the present invention, the chemical and mechanical polishing composition comprises an abrasive component, a corrosion inhibitor, a surfactant, a diacid compound, a metal residue inhibitor and water, wherein the metal residue inhibitor has the formula Compounds and combinations thereof:

Wherein R ¹ , R ² , R ³ and R ⁴ are independently selected from the group consisting of H, C ₁ -C ₆ alkyl, C ₂ -C ₆ alkenyl, and C ₂ -C ₆ alkylidine; R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are independently selected from the group consisting of H and C ₁ -C ₆ alkyl.

desirable Example  details

Preferred embodiments of the chemical and mechanical polishing compositions according to the invention include abrasive components, corrosion inhibitors, surfactants, diacid compounds, metal residue inhibitors and water. The metal residue inhibitor is selected from the group consisting of compounds having the formula and combinations thereof:

Wherein R ¹ , R ² , R ³ and R ⁴ are independently selected from the group consisting of H, C ₁ -C ₆ alkyl, C ₂ -C ₆ alkenyl, and C ₂ -C ₆ alkylidine; R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are independently selected from the group consisting of H and C ₁ -C ₆ alkyl.

The abrasive component is present in an amount ranging from 0.10 to 25.00 wt%, the corrosion inhibitor is present in an amount ranging from 0.01 to 1.00 wt%, the surfactant is present in an amount ranging from 0.01 to 1.00 wt%, and the discrete The compound is present in an amount ranging from 0.01 to 1.00% by weight, the metal residue inhibitor is present in an amount ranging from 0.01 to 1.00% by weight, with the remainder being water.

Preferably, when the metal residue inhibitor is selected from the group consisting of compound (I), compound (II), compound (III) and compound (IV), the content of each of the components is as follows: 0.50 to 10.00 weight percent, corrosion inhibitor is 0.01 to 0.50 weight percent, surfactant is 0.01 to 0.50 weight percent, diacid compound is 0.05 to 1.00 weight percent, metal residue inhibitor is 0.01 to 0.50 weight percent, the remainder is water. More preferably, the abrasive component is 0.50 to 5.00% by weight, the corrosion inhibitor is 0.01 to 0.20% by weight, the surfactant is 0.01 to 0.30% by weight, the diacid compound is 0.10 to 1.00% by weight, and the metal residue inhibitor is 0.01 to 0.30% by weight. %, The rest is water. In particular, when the metal residue inhibitor is compound (I), its content is in the range of 0.01 to 0.10% by weight.

In contrast, where the metal residue inhibitor is Compound (V), the content of each of the components is as follows: 0.50 to 10.00 weight percent of the abrasive component, 0.01 to 0.50 weight percent of the corrosion inhibitor, and 0.01 to 0.50 weight of the surfactant. %, Diacid compound is 0.05-1.00 wt%, metal residue inhibitor is 0.05-1.00 wt%, the remainder is water. More preferably, the abrasive component is 0.50 to 5.00% by weight, the corrosion inhibitor is 0.01 to 0.20% by weight, the surfactant is 0.01 to 0.30% by weight, the diacid compound is 0.10 to 1.00% by weight, and the metal residue inhibitor is 0.05 to 0.50% by weight. %, The rest is water.

Here, it should be noted that when the polishing rate is less than 3,000 mV / min, the polishing rate can be increased by increasing the amount of the diacid compound. The amount of surfactant can be increased to reduce the degree of dishing, and the metal residue inhibitor can be increased to solve metal residue problems.

Preferably, the pH of the composition is in the range of 2-5, more preferably in the range of 3-4.

Preferably, compound (II) is selected from the group consisting of 2,2-dimethylsuccinic acid, 2-ethyl-2-methylsuccinic acid and 2,3-dimethylsuccinic acid.

Compound (III) may be cis or trans. Preferably, compound (III) is selected from the group consisting of maleic acid, 2-methylmaleic acid, fumaric acid and 2-methylfumaric acid.

Preferably, compound (IV) is 2-hydroxyacetic acid, 2-methyl-2-hydroxyacetic acid, 2-ethyl-2-hydroxyacetic acid, 2,2-diethyl-2-hydroxyacetic acid and 2- Ethyl-2-methyl-2-hydroxyacetic acid.

Preferably, compound (V) is selected from the group consisting of acrylic acid, 2-methylacrylic acid, 2-ethylacrylic acid, 3-methylacrylic acid and 2,3-dimethylacrylic acid.

Suitable surfactants for use in the present invention vary with practical requirements. Preferably, the surfactant is anionic or nonionic.

The abrasive component is a commercially available product and varies with practical requirements. Preferably, the abrasive component is selected from the group consisting of SiO ₂ , Al ₂ O ₃ , ZrO ₂ , CeO ₂ , SiC, TiO ₂ , Si ₃ N ₄ , and combinations thereof. In addition, the particle size varies depending on the practical requirements. It is preferred that the particle size range from 15 nm to 30 nm.

Corrosion inhibitors may be any product commercially available that is used in the semiconductor art and has a corrosion protection effect. Preferably, the corrosion inhibitor is benzotriazole, 1,3,5-triazine-2,4,6-triol, 1,2,3-triazole, 3-amino-1,2,4-tria Sol, 3-nitro-1,2,4-triazole, 4-amino-3-hydrazino-1,2,4-triazole-5-thiol, benzotriazole-5-carboxylic acid, 3-amino-1 , 2,4-triazole-5-carboxylic acid, 1-hydroxybenzotriazole, nitrobenzotriazole, and combinations thereof.

The diacid compound may be linear or branched. Preferably, the diacid compound is selected from the group consisting of succinic acid, adipic acid, glutaric acid, and combinations thereof.

The water used in the present invention is preferably deionized water.

The method for preparing the chemical and mechanical polishing composition comprises the steps of mixing an abrasive component, a surfactant, a corrosion inhibitor, a diacid compound, a metal residue inhibitor and deionized water; And adjusting the pH of the mixture to 2 to 5, preferably 3 to 4, using a suitable acid or base. Suitable acids or bases are not limited. Preferably, the acid is hydrochloric acid or nitric acid. The base may be ammonia or tetramethylammonium hydroxide (TMAH).

Preferably, the CMP composition further comprises an oxidizing agent selected from the group consisting of hydrogen peroxide, ferric nitrate, potassium iodide, acetic hydroperoxide and potassium permanganate. The weight ratio of the oxidant to the mixture of the abrasive component, the corrosion inhibitor, the surfactant, the diacid compound, the metal residue inhibitor and the deionized water is from 1: 9 to 1:30.

Preferably, the chemical and mechanical polishing composition further comprises formic acid to increase the polishing rate and reduce the dishing effect on the wafer surface. The amount of formic acid can be adjusted according to practical requirements, preferably in the range of 0.01 to 1.00% by weight.

Example

The following metal residue inhibitor compounds were used to prepare the CMP compositions of Examples 1-9; 1,2,3,4-butanetetracarboxylic acid (hereinafter referred to as compound (I)), methylenesuccinic acid, fumaric acid, 2-hydroxyacetic acid, and acrylic acid (available from Aldrich Company). Each of these compounds was mixed with 2.00 wt% colloidal silica, 0.05 wt% benzotriazole, 0.4 wt% adipic acid, 0.2 wt% anionic surfactant, optional formic acid, and water to obtain a mixture. The CMP compositions of Examples 1-9 were formed by mixing hydrogen peroxide with each of the mixtures in a weight ratio of 1:11 and then adjusting the pH to a range of 3-4. Table 1 shows the types and amounts of metal residue inhibitors and diacid compounds and the amounts of formic acid used in Examples 1-9.

The CMP compositions of Comparative Examples 1 to 4 contain 2.00 wt% colloidal silica, 0.05 wt% benzotriazole, diacid compounds (0.4 wt% adipic acid, 0.4 wt% adipic acid and 0.1 wt% glutaric acid). And 0.4 wt% adipic acid and 0.2 wt% glutaric acid were used in Comparative Examples 1-4), 0.2 wt% anionic surfactant, optional formic acid and water. In the comparative example, no metal residue inhibitor was used.

Membrane pressure 1.0-1.5 psi, support ring pressure in a polishing apparatus (AMAT / Mirra, Applied Material, Inc.) using the composition in Examples 1-9 and the compositions in Comparative Examples 1-4 The wafer with the copper metal layer was polished under conditions of 1.8 psi, platen speed 70 rpm, carrier speed 74 rpm, 25 ° C., and slurry flow rate 200 ml / min. The polishing stage used in the examples is CUP 4410. Polishing time was determined by the End Point System coupled to the polishing apparatus. After polishing, further 20% polishing was performed. Subsequently, wafer cleaning and nitrogen drying were performed using a cleaning apparatus (Evergreen Model 10X, manufactured by Solid State Equipment Corp.).

The polishing rate was determined by the thickness of the copper metal removed per minute. The thickness of the removed copper metal was measured by KLA-Tencor RS-75 manufactured by KLA-TENCOR Company.

The degree of dishing was determined by a surface profiler (KLA-Tencor P-11, manufactured by KLA-TENCOR Company) in order to measure dishing between the barrier layer and a copper wire having a line width of 10 µm used as a measurement criterion.

Metal residues were visually observed.

TABLE 1

Discrete Compound / Content (wt%) Formic acid (% by weight) Metal residue inhibitor / content (% by weight) Polishing Speed (Å / min) Dicing accuracy (Å / Cu line width 100㎛) Metal residue Comparative Example 1 Adipic acid / 0.4 - - 4566 784 has exist Comparative Example 2 Glutaric acid / 0.1 adipic acid / 0.4 - - 6044 452 has exist Comparative Example 3 Glutaric Acid / 0.2 Adipic Acid / 0.4 - - 6438 440 has exist Comparative Example 4 Adipic acid / 0.4 0.1 - 6390 416 has exist Example 1 Adipic acid / 0.4 - Compound (I) /0.02 4882 468 none Example 2 Adipic acid / 0.4 - Compound (I) /0.06 5630 579 none Example 3 Adipic acid / 0.4 - Methylene succinic acid /0.1 5435 418 none Example 4 Adipic acid / 0.4 - Compound (I) /0.06 Methylene Succinic Acid / 0.1 5745 549 none Example 5 Adipic acid / 0.4 - Fumaric Acid / 0.06 5475 397 none Example 6 Adipic acid / 0.4 - 2-hydroxy acetic acid / 0.05 5127 397 none Example 7 Adipic acid / 0.4 - Compound (I) /0.06 2-hydroxyacetic acid /0.05 5945 692 none Example 8 Adipic acid / 0.4 - Acrylic acid / 0.5 5294 344 none Example 9 Adipic acid / 0.4 0.1 Compound (I) /0.02 6313 426 none

(Note) "-" means not added.

As can be seen from Table 1, no metal residue on the wafer surface was observed in Examples 1 to 9 of the present invention, the degree of dishing was less than 700 kPa, and the polishing rate was maintained at 4,800 kPa / min or more. However, metal residues were observed in the comparative examples. In addition, from Examples 1, 2, 3, 4, 6 and 7, an increase in compound (I), a combination of compound (I) and methylenesuccinic acid, and a combination of compound (I) and 2-hydroxyacetic acid were also included in the polishing process. It can be seen that the degree is improved. In addition, when comparing Example 9 with Comparative Example 1, the addition of formic acid improves the polishing rate and reduces the degree of dishing and the phenomenon of metal residue.

By including metal residue inhibitors, surfactants, corrosion inhibitors and discrete compounds in the CMP compositions of the present invention, the CMP compositions of the present invention not only reduce dishing and metal residue phenomena, but also maintain polishing rates above 4,800 kPa / min. You can.

Although what has been described as being the most practical and preferred embodiments as described above, the present invention is not limited to the disclosed embodiments, it is understood that the invention encompasses various modifications included in the spirit and scope and the equivalent range of the broadest interpretation Should be.

The present invention provides a CMP composition capable of reducing the degree of dishing and metal residue on the wafer surface while maintaining the polishing rate at the required level.

Claims (27)

A chemical and mechanical polishing composition comprising an abrasive component, a corrosion inhibitor, a surfactant, a diacid compound, a metal residue inhibitor of formula (I) and water:

The method of claim 1, The abrasive component is present in an amount ranging from 0.10 to 25.00 wt%, the corrosion inhibitor is present in an amount ranging from 0.01 to 1.00 wt%, the surfactant is present in an amount ranging from 0.01 to 1.00 wt%, and the discrete The compound is present in an amount ranging from 0.01 to 1.00% by weight, the metal residue inhibitor is present in an amount ranging from 0.01 to 1.00% by weight, and the remainder is water. The method of claim 2, Wherein said abrasive component is present in an amount ranging from 0.50 to 10.00% by weight. The method of claim 3, Wherein said abrasive component is present in an amount ranging from 0.50 to 5.00% by weight. The method of claim 2, Wherein the corrosion inhibitor is present in an amount ranging from 0.01 to 0.50% by weight. The method of claim 5, Wherein the corrosion inhibitor is present in an amount in the range of 0.01 to 0.20% by weight. The method of claim 2, Wherein said surfactant is present in an amount ranging from 0.01 to 0.50% by weight. The method of claim 7, wherein Wherein said surfactant is present in an amount ranging from 0.10 to 0.30% by weight. The method of claim 2, Wherein said diacid compound is present in an amount in the range of 0.05-1.00% by weight. The method of claim 9, Wherein said diacid compound is present in an amount ranging from 0.10 to 1.00% by weight. The method of claim 2, The metal residue inhibitor is present in an amount in the range of 0.01 to 0.50% by weight. The method of claim 11, Wherein said metal residue inhibitor is present in an amount ranging from 0.01 to 0.30% by weight. delete delete delete delete delete delete The method of claim 1, The corrosion inhibitor is benzotriazole, 1,3,5-triazine-2,4,6-triol, 1,2,3-triazole, 3-amino-1,2,4-triazole, 3 -Nitro-1,2,4-triazole, 4-amino-3-hydrazino-1,2,4-triazole-5-thiol, benzotriazole-5-carboxylic acid, 3-amino-1,2, A chemical and mechanical polishing composition, characterized in that it is selected from the group consisting of 4-triazole-5-carboxylic acid, 1-hydroxybenzotriazole, nitrobenzotriazole, and combinations thereof. The method of claim 1, The surfactant is selected from the group consisting of anionic surfactants and nonionic surfactants, chemical and mechanical polishing composition. The method of claim 1, The diacid compound is selected from the group consisting of succinic acid, adipic acid, glutaric acid, and combinations thereof. The method of claim 1, A chemical and mechanical polishing composition comprising a pH in the range of 2-5. The method of claim 22, A chemical and mechanical polishing composition characterized by having a pH in the range of 3-4. The method of claim 1, The abrasive component is selected from the group consisting of SiO ₂ , Al ₂ O ₃ , ZrO ₂ , CeO ₂ , SiC, TiO ₂ , Si ₃ N ₄ , and a combination thereof. The method of claim 1, A chemical and mechanical polishing composition further comprising an oxidizing agent selected from the group consisting of hydrogen peroxide, ferric nitrate, potassium iodide, acetic hydroperoxide and potassium permanganate. The method of claim 25, And wherein the weight ratio of said oxidant to a mixture of said abrasive component, said corrosion inhibitor, said surfactant, said diacid compound, said metal residue inhibitor and water is from 1: 9 to 1:30. The method of claim 2, A chemical and mechanical polishing composition further comprising 0.01 to 1.00% by weight of formic acid.