Chemical mechanical polishing solution as well as preparation method and application thereof

Abstract

The invention discloses a chemical mechanical polishing solution. The chemical mechanical polishing solution comprises the following components in percentage by mass: 0.8%-10% of grinding particles, 0.001%-0.5% of an accelerating agent, 0.001%-0.5% of an acylamino Gemini quaternary ammonium salt cationic surfactant, 0.001%-1% of a cyclic oligosaccharide compound and the balance of water. The invention also discloses a preparation method and application of the chemical mechanical polishing solution. The chemical mechanical polishing solution can adjust the selection ratio of polycrystalline silicon to silicon dioxide, and avoids or reduces the generation of defects such as recesses, scratches and the like in the polishing process.

Description

Technical Field

[0001] The invention relates to the technical field of polishing liquid, and in particular to a chemical mechanical polishing liquid and a preparation method and application thereof. Background Art

[0002] In integrated circuit manufacturing, as the technology nodes continue to shrink, the complexity of the interconnect structure has increased significantly, and multi-layer deposition processes have become the norm, which directly leads to extreme irregularities in the surface morphology of the substrate. Chemical mechanical polishing is usually used in the prior art to achieve a high degree of flatness on the surface of a silicon wafer. The chemical mechanical polishing process is to use a mixture containing an abrasive and a polishing pad to polish a silicon wafer surface. In a typical chemical mechanical polishing method, the substrate is directly contacted with a rotating polishing pad, and a load is used to apply pressure to the back of the substrate. During polishing, the pad and the operating table rotate while maintaining a downward force on the back of the substrate, and a polishing liquid or polishing slurry is applied to the pad, and the polishing liquid chemically reacts with the film being polished to start the polishing process.

[0003] However, in a multi-layer structure where polysilicon and silicon dioxide coexist, the CMP process faces two major problems: First, the high polishing rate selectivity between polysilicon and silicon dioxide makes it inevitable that there will be dishing of polysilicon when the final polishing process stops on the silicon dioxide layer; second, during the shallow trench isolation (STI) chemical mechanical polishing process, dishing forms on the silicon dioxide surface, causing polysilicon to remain in the silicon dioxide dishing during the subsequent step of polishing after covering the polysilicon layer.

[0004] Therefore, it is extremely important to solve the problem of dish-shaped concave defects on the surface of polysilicon during polishing, and to remove the dish-shaped concave defects of silicon dioxide with residual polysilicon. US2003 / 0153189A1 discloses a chemical mechanical polishing liquid and method for polishing polysilicon, the polishing liquid includes a polymer surfactant and a grinding particle selected from aluminum oxide and cerium oxide, the polymer surfactant is a polycarboxylate surfactant, and the use of the slurry can make the polishing rate of large areas on the surface of polysilicon much higher than the polishing rate in the groove, thereby reducing the concave. US2003 / 0216003A1 and US2004 / 0163324A1 disclose a method for manufacturing Flash. It includes a polishing liquid for polishing polysilicon, the polishing liquid contains at least one compound containing -N(OH), -NH(OH), -NH2(OH) groups, and the polishing selectivity ratio of polysilicon to silicon dioxide using the slurry is greater than 50. US2004 / 0123528A1 discloses an acidic polishing liquid containing abrasive particles and an anionic compound, wherein the anionic compound can reduce the removal rate of the protective layer film and improve the removal rate selection ratio of polysilicon and the protective layer film. US2005 / 0130428A1 and CN1637102A disclose a slurry for chemical mechanical polishing of polysilicon, wherein the slurry composition includes one or more non-ionic surfactants that form a passivation layer on the polysilicon layer and a second surfactant that can form a second passivation layer to reduce the removal rate of silicon nitride or silicon oxide. Patent document US6191039 discloses a chemical mechanical polishing method that can reduce the time and cost of chemical polishing and has a good flattening effect.

[0005] However, although the above technologies have achieved a certain flattening effect to a certain extent and shortened the polishing time and cost, they are either operated in two steps or simply suppress the polishing rate of polysilicon, which is not conducive to the removal of polysilicon in the silicon dioxide butterfly depression. In addition, the operation is complicated and the polishing effect is limited. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the present invention provides a chemical mechanical polishing liquid, a preparation method and an application thereof. By adjusting the amount of an accelerator, an amide-based quaternary ammonium salt cationic surfactant and a cyclic oligosaccharide compound, a polishing liquid with a suitable polysilicon to silicon dioxide selectivity can be obtained, while avoiding or reducing the occurrence of defects such as dents and scratches during the polishing process.

[0007] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0008] A chemical mechanical polishing liquid, wherein the mass percentage of each component of the chemical mechanical polishing liquid is as follows: 0.8% to 10% of abrasive particles, 0.001% to 0.5% of a speed increasing agent, 0.001% to 0.5% of an amide-based quaternary ammonium salt cationic surfactant, 0.001% to 1% of a cyclic oligosaccharide compound, and the balance is water.

[0009] According to one aspect of the present invention, the molecular structure of the amido-based quaternary ammonium salt cationic surfactant is: Wherein R1, R2, R3, R4, and R5 are alkyl groups with a carbon chain of 1 to 18; and X is one of hydroxide ion, chloride ion, bromide ion, and iodide ion.

[0010] According to one aspect of the present invention, the speed increasing agent is a polyacid compound.

[0011] According to one aspect of the present invention, the polyacid compound is a dibasic acid, a tribasic acid, a tetrabasic acid compound and an addition salt thereof.

[0012] According to one aspect of the present invention, the polyacid compound is one or a combination of oxalic acid, tricarballylic acid, citric acid, malic acid, oxalic acid, succinic acid, L-tartaric acid, D-tartaric acid, dicarboxymethylalanine, butanetetracarboxylic acid, tricarballylic acid, 1,3,5-pentanetricarboxylic acid, ethylenediaminetetraacetic acid, diethyltriaminepentaacetic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1,2,4-butanetricarboxylic acid, nitrilotriacetic acid and / or 1,2-propylenediamine-N,N,N',N'-tetraacetic acid.

[0013] According to one aspect of the present invention, the cyclic oligosaccharide compound is one or more of α-cyclodextrin, β-cyclodextrin and / or γ-cyclodextrin.

[0014] According to one aspect of the present invention, the abrasive particles are one or more of silicon dioxide, aluminum oxide, cerium dioxide and / or titanium dioxide abrasive particles.

[0015] According to one aspect of the present invention, the particle size of the abrasive particles is 80-120 nm.

[0016] According to one aspect of the present invention, the method for preparing the chemical mechanical polishing solution comprises the following steps:

[0017] Configure the required components;

[0018] Mix all ingredients well.

[0019] According to one aspect of the present invention, the chemical mechanical polishing liquid is used in the polishing process of single crystal silicon and polycrystalline silicon.

[0020] Advantages of the implementation of the present invention: the amido-Jimic quaternary ammonium salt cationic surfactant in the chemical mechanical polishing liquid can significantly reduce the removal rate of polysilicon without reducing the removal rate of silicon dioxide, thereby significantly reducing the selectivity of polysilicon to silicon dioxide; the polyacid accelerator can significantly increase the removal rate of polysilicon. The cyclic polysaccharide compound, the polyacid accelerator, and the amido-Jimic quaternary ammonium salt cationic surfactant form a compounding effect, which can significantly increase the removal rate of polysilicon and greatly improve the selectivity of polysilicon to silicon dioxide. The chemical mechanical polishing liquid adjusts the polysilicon / silicon dioxide selectivity of the polishing liquid by controlling the content of the amido-Jimic quaternary ammonium salt cationic surfactant, the polyacid accelerator, and the cyclic polysaccharide compound, while avoiding or reducing the generation of defects such as depressions and scratches during the polishing process. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] A chemical mechanical polishing liquid, wherein the mass percentage of each component of the chemical mechanical polishing liquid is as follows: 0.8% to 10% of abrasive particles, 0.001% to 0.5% of a speed increasing agent, 0.001% to 0.5% of an amide-based quaternary ammonium salt cationic surfactant, 0.001% to 1% of a cyclic oligosaccharide compound, and the balance is water.

[0023] In practical applications, the molecular structure of the amide-based quaternary ammonium salt cationic surfactant is:

[0024]

[0025] Wherein R1, R2, R3, R4, and R5 are alkyl groups with a carbon chain of 1 to 18; and X is one of hydroxide ion, chloride ion, bromide ion, and iodide ion.

[0026] Specifically, the amido-based quaternary ammonium salt cationic surfactant can be N, N'-bis (acetylaminomethyl) -N, N, N', N'-tetramethylmethane dichloride, N- (acetylaminomethyl) -N, N, N', N'-tetramethyl-N- (propionylaminomethyl) methane dibromide, N, N'-bis (propionylaminomethyl) -N, N, N', N'-tetramethylmethane dichloride, N- (2-acetylaminoethyl) -N- (acetylaminomethyl) -N, N, N', N'-tetramethylmethane Ammonium dibromide, N1-N2-bis(acetylaminomethyl)-N1,N1,N2,N2-tetramethylethane-1,2-dibromide, N,N'-bis(butyrylamidemethyl)-N,N,N',N'-tetramethylmethylammonium dibromide, N,N'-bis(pentanamidomethyl)-N,N,N',N'-tetramethylmethylammonium dibromide, N,N'-bis(hexanamidomethyl)-N,N,N',N'-tetramethylmethylammonium dichloride, N,N'-bis(heptylamidomethyl)-N,N,N',N'-tetramethyl N,N'-bis(octanamidomethyl)-N,N,N',N'-tetramethylammonium dibromide, N,N'-bis(octanamidomethyl)-N,N,N',N'-tetramethylammonium diiodide, N,N'-bis(nonanamidomethyl)-N,N,N',N'-tetramethylammonium dibromide, N,N'-bis(decanamidomethyl)-N,N,N',N'-tetramethylammonium dibromide, N,N'-bis(undecanamidomethyl)-N,N,N',N'-tetramethylammonium dibromide , N,N'-bis(dodecanoylaminomethyl)-N,N,N',N'-tetramethylammonium dibromide, N,N'-bis(tridecaproylaminomethyl)-N,N,N',N'-tetramethylammonium dichloride, N,N'-bis(tetradecanoylaminomethyl)-N,N,N',N'-tetramethylammonium dibromide, N,N'-bis(pentadecanoylaminomethyl)-N,N,N',N'-tetramethylammonium dibromide, N,N'-bis(hexadecanoylaminomethyl)-N,N,N',N'-tetramethylammonium dibromide, etc.

[0027] In practical applications, the speed increasing agent is a polyacid compound, and the polyacid compound is a dibasic acid, a tribasic acid, a tetrabasic acid compound and an addition salt thereof.

[0028] In practical applications, the polyacid compound is one or a combination of oxalic acid, tricarballylic acid, citric acid, malic acid, oxalic acid, succinic acid, L-tartaric acid, D-tartaric acid, dicarboxymethylalanine, butanetetracarboxylic acid, tricarballylic acid, 1,3,5-pentanetricarboxylic acid, ethylenediaminetetraacetic acid, diethyltriaminepentaacetic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1,2,4-butanetricarboxylic acid, nitrilotriacetic acid and / or 1,2-propylenediamine-N,N,N',N'-tetraacetic acid.

[0029] In practical applications, the cyclic oligosaccharide compound is one or more of α-cyclodextrin, β-cyclodextrin and / or γ-cyclodextrin.

[0030] In practical applications, the abrasive particles are commonly used abrasive particles in the art, such as one or more of silicon dioxide, aluminum oxide, cerium dioxide, and titanium dioxide abrasive particles. The particle size of the abrasive particles is preferably 20 to 150 nm, preferably 80 to 120 nm.

[0031] In practical applications, the polishing liquid further includes a pH adjuster, and the pH adjuster can be selected from hydrochloric acid, phosphoric acid, nitric acid, acetic acid or sulfuric acid, etc. Preferably, the pH value of the polishing liquid is adjusted to 7-12 by the pH adjuster.

[0032] In practical applications, the chemical mechanical polishing liquid further includes a viscosity regulator and / or a defoamer. Specifically, the viscosity regulator and the defoamer can be selected from conventional viscosity regulator and defoamer products on the market.

[0033] In practical applications, the amido-Jimic quaternary ammonium salt cationic surfactant in the chemical mechanical polishing liquid can significantly reduce the removal rate of polysilicon without reducing the removal rate of silicon dioxide, thereby significantly reducing the selectivity of polysilicon to silicon dioxide; the accelerator can significantly increase the removal rate of polysilicon. The cyclic polysaccharide compound, polyacid, and amido-Jimic quaternary ammonium salt cationic surfactant form a compounding effect, which can significantly increase the removal rate of polysilicon and greatly improve the selectivity of polysilicon to silicon dioxide. The mechanical polishing liquid controls the content of amido-Jimic quaternary ammonium salt cationic surfactant, polyacid compound, and cyclic polysaccharide to adjust the polysilicon / silicon dioxide selectivity of the polishing liquid, while avoiding or reducing the generation of defects such as depressions and scratches during the polishing process.

[0034] In practical applications, the preparation method of the chemical mechanical polishing liquid comprises the following steps:

[0035] Configure the required components;

[0036] Mix all ingredients well.

[0037] In practical applications, the chemical mechanical polishing liquid is used in the polishing process of single crystal silicon and polycrystalline silicon.

[0038] The advantages of the present invention are further described below through more specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0039] Table 1 shows the formulas of Examples 1 to 19 and Comparative Examples 1 to 18 of the chemical mechanical polishing solution of the present invention. The polishing solution can be obtained by mixing the components and their contents given in the table evenly, and water is added to make up to 100% by mass and adjusted to the required pH value. An oxidant is added before use and mixed evenly.

[0040] Table 1

[0041]

[0042]

[0043]

[0044]

[0045] In order to verify the use effect of the chemical mechanical polishing liquid of the present invention, effect verification example 1 is set up for illustration.

[0046] Effect verification example 1:

[0047] The polishing liquids of comparative examples 1 to 18 and the polishing liquids of embodiments 17 to 19 of the present invention were used to perform chemical mechanical polishing experiments on polysilicon and silicon dioxide (Teos). The polishing conditions were as follows: the polishing machine was Logitech PM5 Polisher, 12-inch politex polishing pad, 4cm*4cm square wafer, grinding pressure was 3psi, grinding table speed was 70 rpm, grinding head rotation speed was 150 rpm, and polishing liquid drop speed was 100mL / min. TEOS scratch evaluation and dent (Dishing) defect evaluation were performed respectively. Specifically, TEOS scratch evaluation was to observe scratches on TEOS under an optical microscope after polishing; dent (Dishing) defect evaluation was to use SKW company to manufacture STI3 mode wafers for dent defect evaluation polishing experiments, and the dent defect depth was evaluated by AFM analysis. At the same time, the removal rate values ​​of each polishing liquid for polysilicon and silicon dioxide were measured, and the selectivity of polysilicon to silicon dioxide was calculated to obtain Table 2.

[0048] Table 2

[0049]

[0050]

[0051] As can be seen from Table 2, compared with Comparative Examples 1 to 18, the scratches and dents of Examples 17 to 19 are greatly reduced.

[0052] Compared with comparative examples 13 to 15 in which amide-based quaternary ammonium salt cationic surfactants were not added, embodiments 17 to 19 in which amide-based quaternary ammonium salt cationic surfactants were added significantly reduced the removal rate of polysilicon while having little effect on the removal rate of silicon dioxide, thereby reducing the selectivity of polysilicon to silicon dioxide.

[0053] Compared with comparative examples 7 to 9 without adding an accelerating agent, examples 17 to 19 added an accelerating agent. When other components and their contents were the same, the addition of the polyacid compound as an accelerating agent significantly increased the removal rate of polysilicon.

[0054] Compared with Comparative Examples 16 to 18 in which no cyclic polysaccharide compound is added, Examples 17 to 19 add cyclic polysaccharide compounds. When other components and their contents are the same, the addition of cyclic polysaccharide compounds, the speed increaser, and the amide-based quaternary ammonium salt cationic surfactant form a complex effect, which significantly increases the removal rate of polysilicon and greatly improves the selectivity of polysilicon to silicon dioxide.

[0055] Therefore, the chemical mechanical polishing liquid adjusts the polysilicon / silicon dioxide selectivity of the polishing liquid by controlling the content of the amido-gimmick quaternary ammonium salt cationic surfactant, the polyacid compound and the cyclic polysaccharide, thereby avoiding or reducing the generation of defects such as depressions and scratches during the polishing process.

[0056] Advantages of the implementation of the present invention: the amido-Jimic quaternary ammonium salt cationic surfactant in the chemical mechanical polishing liquid can significantly reduce the removal rate of polysilicon without reducing the removal rate of silicon dioxide, thereby significantly reducing the selectivity of polysilicon to silicon dioxide; the speed-increasing agent can significantly increase the removal rate of polysilicon. The cyclic polysaccharide compound, the polyacid speed-increasing agent, and the amido-Jimic quaternary ammonium salt cationic surfactant form a compounding effect, which can significantly increase the removal rate of polysilicon, and greatly improve the selectivity of polysilicon to silicon dioxide. The chemical mechanical polishing liquid adjusts the polysilicon / silicon dioxide selectivity of the polishing liquid by controlling the content of the amido-Jimic quaternary ammonium salt cationic surfactant, the polyacid speed-increasing agent, and the cyclic polysaccharide compound, while avoiding or reducing the generation of defects such as depressions and scratches during the polishing process.

[0057] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the art within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A chemical mechanical polishing liquid, characterized in that: The mass percentages of the components of the chemical mechanical polishing solution are as follows: The invention comprises 0.8% to 10% of abrasive particles, 0.001% to 0.5% of a speed increasing agent, 0.001% to 0.5% of an amido-Gemilk quaternary ammonium salt cationic surfactant, 0.001% to 1% of a cyclic oligosaccharide compound, and the balance is water.

2. A chemical mechanical polishing solution according to claim 1, characterized in that: The molecular structure of the amido-based quaternary ammonium salt cationic surfactant is: Wherein R1, R2, R3, R4, and R5 are alkyl groups with a carbon chain of 1 to 18; and X is one of hydroxide ion, chloride ion, bromide ion, and iodide ion.

3. A chemical mechanical polishing solution according to claim 2, characterized in that: The speed increasing agent is a polyacid compound.

4. A chemical mechanical polishing solution according to claim 3, characterized in that: The polyacid compounds are dibasic acid, tribasic acid, tetrabasic acid compounds and addition salts thereof.

5. A chemical mechanical polishing solution according to claim 4, characterized in that: The polyacid compound is one of oxalic acid, tricarballylic acid, citric acid, malic acid, oxalic acid, succinic acid, L-tartaric acid, D-tartaric acid, dicarboxymethylalanine, butanetetracarboxylic acid, 1,3,5-pentanetricarboxylic acid, ethylenediaminetetraacetic acid, diethyltriaminepentaacetic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, 1,2,4-butanetricarboxylic acid, nitrilotriacetic acid and / or 1,2-propylenediamine-N,N,N',N'-tetraacetic acid or a combination thereof.

6. A chemical mechanical polishing solution according to claim 2, characterized in that: The cyclic oligosaccharide compound is one or more of α-cyclodextrin, β-cyclodextrin and / or γ-cyclodextrin.

7. The chemical mechanical polishing solution according to claim 2, characterized in that: The abrasive particles are one or more of silicon dioxide, aluminum oxide, cerium dioxide and / or titanium dioxide.

8. The chemical mechanical polishing solution according to claim 7, characterized in that: The particle size of the abrasive particles is 80-150 nm.

9. The method for preparing a chemical mechanical polishing solution according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: Configure the required components; Mix all ingredients well.

10. Use of the chemical mechanical polishing liquid according to any one of claims 1 to 8 in the polishing process of single crystal silicon and polycrystalline silicon.

Images