KrF photoresist composition and preparation method thereof

Abstract

The invention relates to the technical field of photoresist, and particularly discloses a KrF photoresist composition and a preparation method thereof. The KrF photoresist composition comprises KrF resin, organic alkali, a surfactant, a photoacid generator and an organic solvent, wherein the KrF resin is prepared by copolymerizing four monomers with a structural general formula A-D; the specific preparation method comprises the following steps: uniformly mixing the KrF resin, the organic alkali, the surfactant, the photoacid generator and the organic solvent in a nitrogen atmosphere according to a ratio to obtain the KrF photoresist composition. The KrF photoresist composition obtained by the invention has the advantages of high light sensitivity and high resolution.

Description

Technical Field

[0001] This invention belongs to the field of photoresist technology, specifically relating to a KrF photoresist composition and its preparation method. Background Technology

[0002] Photolithography and etching are key technologies in semiconductor chip manufacturing, and photoresist is a core material in modern semiconductor chip photolithography. In the photolithography process of semiconductor chip manufacturing, a photomask pattern is projected onto the photoresist using a light source of a specific wavelength from an exposure machine. The photoresist undergoes a photochemical reaction, and the desired lithographic pattern is finally obtained through baking and development under set conditions. In semiconductor processes, photoresist serves as the process mask layer, and the quality of the resulting pattern and the physicochemical properties of the film play a crucial role in subsequent processes, directly affecting the chip's device performance. However, traditional photoresist materials may have resolution limitations or insufficient photosensitivity at high resolutions. Therefore, given the urgent need for higher resolution and higher performance microelectronic devices, finding a high-resolution, high-sensitivity photoresist resin and photoresist composition is of great significance. Summary of the Invention

[0003] To address the shortcomings of existing photoresist resins in terms of photosensitivity and resolution, this invention provides a KrF photoresist composition and its preparation method that can improve photosensitivity and resolution. To achieve the above-mentioned objectives, the technical solution of this invention is as follows:

[0004] In a first aspect, the present invention provides a KrF photoresist composition, wherein the mass percentage comprises:

[0005] KrF resin: 5%–50%, preferably 10%–30%;

[0006] Organic base: 0.01–10%, preferably 0.05–5%;

[0007] Surfactant: 0.01-10%, preferably 0.1-5%;

[0008] Photo-induced acid-producing agent: 0.1-15%, preferably 0.5-5%;

[0009] Organic solvent: 15-90%, preferably 55-85%.

[0010] In this invention, the KrF resin is obtained by copolymerization of monomers having general formulas A to D:

[0011]

[0012] Where R1~R 11Alkyl or cycloalkanyl groups, which are independently derived from H or C1-C20 straight-chain or branched-chain, hydroxyl-substituted alkyl groups, or halogen-substituted alkyl groups, respectively.

[0013] Preferably, R1 to R 11 Alkyl or cycloalkanyl groups, which are independently derived from H or C1-C8 straight-chain or branched-chain alkane groups, hydroxyl-substituted alkane groups of C1-C8, or halogen-substituted alkane groups of C1-C8.

[0014] More preferably, R1~R 11 Alkyl groups or cycloalkanes that are independently derived from H or C1-C6 straight-chain or branched alkane groups, or alkane groups substituted with hydroxyl groups from C1-C3.

[0015] In this invention, the molar ratio of monomers A to D is 1:(4-8):(1-3):(0.5-1).

[0016] In this invention, the KrF resin is copolymerized by free radical polymerization, and prepared according to the method of patent US2008 / 0193878 A1.

[0017] In this invention, the KrF resin has a molecular weight of 5,000 to 30,000, preferably 8,000 to 15,000.

[0018] In this invention, the surfactant is selected from one or more of fluorinated surfactants, silicone surfactants, and nonionic surfactants, and preferably from one or more of perfluorooctanoic acid ammonium, perfluorooctyl sulfonate ammonium, perfluorohexanoate ammonium, hexadecyltrimethylsiloxane, methyltriethoxysilane, vinyltriethoxysilane, γ-aminopropyltriethoxysilane, phenyltriethoxysilane, polyethylene glycol octylphenyl ether, polyethylene glycol dodecyl ether, polyethylene glycol octyl ether, polyethylene glycol stearate, polyethylene glycol laurate, sorbitan monooleate, polyvinylpyrrolidone, polyethylene glycol monomethyl ether, polyethylene glycol monoethyl ether, and polyethylene glycol monopropyl ether.

[0019] In this invention, the organic base is selected from one or more of tripropylamine, tributylamine, triisobutylamine, trioctylamine, triethanolamine, triethoxyethanolamine, trimethoxymethoxyethylamine, and tetramethylammonium hydroxide.

[0020] In this invention, the photo-induced acid-producing agent is selected from one or more of onium salts, triazines, sulfonyl diazomethanes, oxime esters, and nitrobenzyl sulfonates, preferably from perfluorobutyltriphenylthionium salt, trifluoromethyltriphenylthionium salt, o-trifluorotolyltriphenylthionium salt, p-trifluorotolyltriphenylthionium salt, perfluorobutyl diphenyliodoium salt, trifluoromethyl diphenyliodoium salt, o-trifluorotolyl diphenyliodoium salt, p-trifluorotolyl diphenyliodoium salt, bis(4-tert-butylphenyl)iodocamphor sulfonate, bis(4-tert-butylphenyl)iodotrifluoromethanesulfonate, trichloroacetophenone, tribromomethylphenyl sulfone, and 4-phenoxydichloroacetophenone. One or more of 4,6-bis(trichloromethyl)-1,3,5-triazine, α,α-bis(arylsulfonyl)diazomethane, α-carbonyl-α-sulfonyldiazomethane, N-trifluoromethylsulfonyloxyphthalimide, N-trifluoromethylsulfonyloxy-1,8-naphthalenediamide, succinimide arylsulfonate, N-hydroxyphthalimide p-toluenesulfonate, o-nitrobenzylsulfonate, α-aromatic sulfonate, α-sulfone acetophenone, and aryl phosphate esters, more preferably one or more of perfluorobutyltriphenylthioonium salt, o-trifluorotoluyltriphenylthioonium salt, and α,α-bis(arylsulfonyl)diazomethane.

[0021] In this invention, the organic solvent is selected from one or more of ketone solvents, polyols, alkyl ethers, alkyl acid ester solvents, and amide solvents, preferably acetone, methyl ethyl ketone, cyclohexanone, methyl isopentyl ketone, 2-heptanone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monobutyl ether, and methoxyacetic acid. Ethyl acetate, ethoxyethyl acetate, propylene glycol methyl ether acetate, propylene glycol propyl ether acetate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone, more preferably one or more of diethylene glycol methyl ethyl ether, propylene glycol monomethyl ether, propylene glycol methyl ether acetate, and ethyl lactate.

[0022] In another aspect, the present invention provides a method for preparing a KrF photoresist composition, the steps of which include: mixing KrF resin, organic base, surfactant, photoacid generator and organic solvent uniformly in a nitrogen atmosphere according to the specified ratio, and then filtering to obtain a photoresist mixture.

[0023] Preferably, the filtration is micron filtration with a filtration accuracy of 0.1 to 2 μm, more preferably 0.1 to 0.5 μm.

[0024] In summary, the present invention has the following beneficial effects:

[0025] 1. The key to this invention lies in the free radical polymerization reaction of monomers A, B, C, and D, thereby obtaining a bridge-structured photoresist resin and KrF photoresist composition with high photosensitivity and high resolution.

[0026] 2. The proportions of KrF resin, organic base, surfactant, photoacid-generating agent and organic solvent used in this invention can effectively suppress acid diffusion after exposure, improve the pattern resolution and photolithography performance under traditional cross-linking conditions, and obtain high-resolution and well-shaped photolithographic patterns. Detailed Implementation

[0027] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0028] Main raw material sources

[0029] Unless otherwise specified, the main raw materials and reagents used in the embodiments and comparative examples of this invention were all purchased through ordinary commercial channels.

[0030] KrF resin: The copolymerization method used is free radical polymerization, which is prepared with reference to the method of patent US2008 / 0193878 A1. The monomer can be obtained through ordinary commercial channels.

[0031] Photo-induced acid-producing agents: α,α-bis(arylsulfonyl)diazomethane and N-hydroxyphthalimide p-toluenesulfonate are prepared according to the method of patent US5344742A; perfluorobutyltriphenylthionium salt, o-trifluorotoluyltriphenylthionium salt, bis(4-tert-butylphenyl)iodotrifluoromethanesulfonate, and bis(4-tert-butylphenyl)iodocamphorsulfonate are prepared according to US6200728B1; the reaction monomers can be purchased through ordinary commercial channels.

[0032] Example 1

[0033] A KrF photoresist composition comprising:

[0034] KrF resin: 20wt% KrF copolymer resin (tert-butyl acrylate, p-hydroxystyrene, styrene, 4-vinyl eugenol in a mass ratio of 1:5:1.6:1), with a molecular weight of 12000;

[0035] Organic base: 0.05 wt% trioctylamine;

[0036] Surfactants: 0.05 wt% ammonium perfluorooctanoate, 0.1 wt% polyethylene glycol dodecyl ether;

[0037] Photo-induced acid-producing agent: 0.2 wt% α,α-bis(arylsulfonyl)diazomethane, 0.3 wt% perfluorobutyltriphenylthionium salt, 0.3 wt% o-trifluorotolyltriphenylthionium salt;

[0038] Organic solvents: 30 wt% diethylene glycol methyl ether, 20 wt% propylene glycol monomethyl ether, and 29 wt% ethyl lactate.

[0039] The preparation method is as follows: KrF resin, organic base, surfactant, photoacid generator and organic solvent are mixed in a one-pot manner under ultra-clean conditions in a nitrogen atmosphere and mechanically stirred at 500 rpm for 5 hours. Then, the mixture is filtered using a 0.11 μm organic filter (the filter element is made of nylon) to obtain the KrF photoresist composition.

[0040] Example 2

[0041] A KrF photoresist composition comprising:

[0042] KrF resin: 15wt% KrF copolymer resin (cyclopentyl acrylate, p-hydroxystyrene, styrene, and mustard alcohol in a mass ratio of 1:4:2.7:0.9), with a molecular weight of 10000;

[0043] Organic bases: 1.5 wt% tripropylamine, 0.5 wt% triethanolamine;

[0044] Surfactant: 0.5wt% ammonium perfluorooctyl sulfonate;

[0045] Photoacid-producing agent: 5 wt% bis(4-tert-butylphenyl)iodotrifluoromethanesulfonate;

[0046] Organic solvent: 77.5 wt% propylene glycol methyl ether acetate.

[0047] The preparation method is the same as in Example 1.

[0048] Example 3

[0049] A KrF photoresist composition comprising:

[0050] KrF resin: 15wt% KrF copolymer resin (tert-butyl acrylate, p-hydroxystyrene, styrene, (E)-2,6-dimethoxy-4-(prop-1-en-1-yl)phenol in a mass ratio of 1:7:2.2:0.7), with a molecular weight of 12000;

[0051] Organic base: 0.4 wt% triisobutylamine;

[0052] Surfactants: 0.05 wt% hexadecyltrimethylsiloxane, 0.05 wt% ammonium perfluorohexanoate;

[0053] Photo-induced acid-producing agent: 0.3 wt% perfluorobutyltriphenylthionium salt, 0.3 wt% o-trifluorotolyltriphenylthionium salt, 0.4 wt% α,α-bis(arylsulfonyl)diazomethane;

[0054] Organic solvents: 40 wt% propylene glycol methyl ether acetate, 43.5 wt% ethyl lactate.

[0055] The preparation method is the same as in Example 1.

[0056] Example 4

[0057] A KrF photoresist composition comprising:

[0058] KrF resin: 25wt% KrF copolymer resin (cyclohexane acrylate, p-hydroxystyrene, styrene, 4-vinyl eugenol in a mass ratio of 1:8:1.1:1), with a molecular weight of 11000;

[0059] Organic bases: 1 wt% triethoxyethanolamine, 1 wt% tripropylamine;

[0060] Surfactant: 1 wt% polyethylene glycol octylphenyl ether;

[0061] Photoacid generator: 5 wt% perfluorobutyltriphenylthionium salt;

[0062] Organic solvents: 20 wt% diethylene glycol methyl ether, 20 wt% propylene glycol monomethyl ether, 27 wt% ethyl lactate.

[0063] The preparation method is the same as in Example 1.

[0064] Example 5

[0065] A KrF photoresist composition comprising:

[0066] KrF resin: 15wt% KrF copolymer resin (tert-butyl acrylate, p-hydroxystyrene, styrene, 1,2,3-trimethoxy-5-vinylbenzene in a mass ratio of 1:6:1:0.7), with a molecular weight of 15000;

[0067] Organic base: 1 wt% tributylamine;

[0068] Surfactants: 0.7 wt% sorbitan monooleate, 0.3 wt% methyltriethoxysilane;

[0069] Photo-induced acid production agent: 1 wt% bis(4-tert-butylphenyl)iodocamphor sulfonate, 1 wt% N-hydroxyphthalimide p-toluenesulfonate;

[0070] Organic solvents: 40 wt% diethylene glycol methyl ethyl ether, 41 wt% ethyl lactate.

[0071] The preparation method is the same as in Example 1.

[0072] Example 6

[0073] A KrF photoresist composition comprising:

[0074] KrF resin: 30wt% KrF copolymer resin (tert-butyl acrylate, p-hydroxystyrene, styrene, 1,2,3-trimethoxy-5-vinylbenzene in a mass ratio of 1:4:2.3:0.8), with a molecular weight of 9000;

[0075] Organic base: 0.5 wt% triethanolamine;

[0076] Surfactant: 1.5wt% ammonium perfluorooctanoate;

[0077] Photo-induced acid-producing agent: 0.4 wt% α,α-bis(arylsulfonyl)diazomethane, 0.3 wt% perfluorobutyltriphenylthionium salt, 0.3 wt% o-trifluorotolyltriphenylthionium salt;

[0078] Organic solvent: 67 wt% ethyl lactate.

[0079] The preparation method is the same as in Example 1.

[0080] Comparative Example 1

[0081] The KrF photoresist composition was prepared according to Example 1, except that the KrF copolymer resin was replaced with an equal mass of a ternary copolymer resin consisting of tert-butyl acrylate, p-hydroxystyrene, and styrene in a mass ratio of 1:5:1.6, with a molecular weight of 12000; other conditions remained unchanged.

[0082] Comparative Example 2

[0083] The KrF photoresist composition was prepared according to Example 1, except that the KrF copolymer resin was replaced with an equal mass of a ternary copolymer resin consisting of tert-butyl acrylate, styrene, and 4-vinyl eugenol in a mass ratio of 1:1.6:1, with a molecular weight of 12000; other conditions remained unchanged.

[0084] Comparative Example 3

[0085] The KrF photoresist composition was prepared according to Example 1, except that the KrF copolymer resin was replaced with an equal mass of a ternary copolymer resin consisting of tert-butyl acrylate, p-hydroxystyrene, and 4-vinyl eugenol in a mass ratio of 1:5:1, with a molecular weight of 12000; other conditions remained unchanged.

[0086] Comparative Example 4

[0087] The KrF photoresist composition was prepared according to Example 1, except that no organic base was added and ethyl lactate was used to make up 100%, while other conditions remained unchanged.

[0088] Test case

[0089] The KrF photoresist compositions of the above examples and comparative examples were spin-coated onto silicon wafers treated with hexamethyldisilazane (1200 rpm, 300 nm thickness). The wafers were pre-baked at 100°C for 60 s to remove solvent, then exposed at 248 nm. After exposure, the wafers were baked at 120°C for 60 s, then developed in 2.38 wt% tetramethylammonium hydroxide (TMAH) developer, and finally hardened on a 120°C hot stage for 60 s. The sensitivity, film thickness changes before and after development, and development resolution patterns were tested at the same resolution. The results are shown in Table 1. The morphology of the sample sections was observed using a scanning electron microscope.

[0090] Table 1

[0091]

[0092] As shown in Table 1, compared to the comparative examples, the KrF photoresist composition prepared in the embodiments of the present invention exhibits higher sensitivity at the same resolution. A comparison of the morphologies of the patterns obtained in the embodiments and comparative examples shows that the patterns obtained in the embodiments have better morphology. Specifically, a comparison of Example 1 and Comparative Examples 1-4 shows that when using the KrF resin of the present invention, the KrF photoresist forms patterns with better morphology and no pattern defects. Examples 1 and Comparative Example 4 show that the appropriate addition of organic base can effectively reduce acid diffusion and significantly improve the pattern morphology. In summary, the KrF photoresist composition provided by the present invention has high resolution and high sensitivity, and also exhibits small changes in film thickness before and after development, demonstrating good chemical stability.

[0093] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A KrF photoresist composition, characterized in that, Includes the following components by mass percentage: KrF resin: 5%–50%, preferably 10%–30%; Organic base: 0.01–10%, preferably 0.05–5%; Surfactant: 0.01-10%, preferably 0.1-5%; Photo-induced acid-producing agent: 0.1-15%, preferably 0.5-5%; Organic solvent: 15-90%, preferably 55-85%.

2. The KrF photoresist composition according to claim 1, characterized in that, The KrF resin is obtained by copolymerization of monomers having general formulas A to D: Where R1~R 11 Each group is independently derived from a straight-chain or branched alkane or cycloalkane group of H or C1-C20, a hydroxyl-substituted alkane group of C1-C20, or a halogen-substituted alkane group of C1-C20; preferably, R1-R 11 Alkyl or cycloalkanyl groups, which are independently derived from H or C1-C8 straight-chain or branched-chain alkane groups, hydroxyl-substituted alkane groups of C1-C8, or halogen-substituted alkane groups of C1-C8.

3. The KrF resin according to claim 2, characterized in that, The molar ratio of monomers A to D is 1:(4-8):(1-3):(0.5-1).

4. The KrF photoresist composition according to claim 2, characterized in that, The KrF resin has a molecular weight of 5,000 to 30,000, preferably 8,000 to 15,000.

5. The KrF photoresist composition according to claim 1, characterized in that, The surfactant is selected from one or more of fluorinated surfactants, silicone surfactants, and nonionic surfactants, and preferably from one or more of perfluorooctanoic acid ammonium, perfluorooctyl sulfonate ammonium, perfluorohexanoate ammonium, hexadecyltrimethylsiloxane, methyltriethoxysilane, vinyltriethoxysilane, γ-aminopropyltriethoxysilane, phenyltriethoxysilane, polyethylene glycol octylphenyl ether, polyethylene glycol dodecyl ether, polyethylene glycol octyl ether, polyethylene glycol stearate, polyethylene glycol laurate, sorbitan monooleate, polyvinylpyrrolidone, polyethylene glycol monomethyl ether, polyethylene glycol monoethyl ether, and polyethylene glycol monopropyl ether.

6. The KrF photoresist composition according to claim 1, characterized in that, The organic base is selected from one or more of tripropylamine, tributylamine, triisobutylamine, trioctylamine, triethanolamine, triethoxyethanolamine, trimethoxymethoxyethylamine, and tetramethylammonium hydroxide.

7. The KrF photoresist composition according to claim 1, characterized in that, The photoacid-producing agent is selected from one or more of onium salts, triazines, sulfonyl diazomethanes, oxime esters, and nitrobenzyl sulfonates, preferably perfluorobutyltriphenylthionium salt, trifluoromethyltriphenylthionium salt, o-trifluorotolyltriphenylthionium salt, p-trifluorotolyltriphenylthionium salt, perfluorobutyl diphenyliodoium salt, trifluoromethyl diphenyliodoium salt, o-trifluorotolyl diphenyliodoium salt, p-trifluorotolyl diphenyliodoium salt, bis(4-tert-butylphenyl)iodocamphor sulfonate, bis(4-tert-butylphenyl)iodotrifluoromethanesulfonate, trichloroacetophenone, tribromomethylphenyl sulfone, 4-phenoxydichloroacetophenone, 4,6- One or more of the following: di(trichloromethyl)-1,3,5-triazine, α,α-bis(arylsulfonyl)diazomethane, α-carbonyl-α-sulfonyldiazomethane, N-trifluoromethylsulfonyloxyphthalimide, N-trifluoromethylsulfonyloxy-1,8-naphthalenediamide, succinimide aryl sulfonate, N-hydroxyphthalimide p-toluenesulfonate, o-nitrobenzyl sulfonate, α-aryl sulfonate, α-sulfone acetophenones, and aryl phosphate esters; more preferably, one or more of perfluorobutyltriphenylthioonium salt, o-trifluorotoluyltriphenylthioonium salt, and α,α-bis(arylsulfonyl)diazomethane.

8. The KrF photoresist composition according to claim 1, characterized in that, The organic solvent is selected from one or more of ketone solvents, polyols, alkyl ethers, alkyl acid ester solvents, and amide solvents, preferably acetone, methyl ethyl ketone, cyclohexanone, methyl isopentyl ketone, 2-heptanone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monobutyl ether, methoxyethyl acetate, etc. Ethoxyethyl acetate, propylene glycol methyl ether acetate, propylene glycol propyl ether acetate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone, more preferably one or more of diethylene glycol methyl ethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and ethyl lactate.

9. A method for preparing a KrF photoresist composition according to any one of claims 1-8, comprising the following steps: under a nitrogen atmosphere, mixing KrF resin, organic base, surfactant, photoacid generator and organic solvent in a specified ratio until homogeneous, and filtering to obtain a photoresist mixture.

10. The preparation method according to claim 9, characterized in that, The filtration is micron filtration with a filtration accuracy of 0.1–2 μm, preferably 0.1–0.5 μm.

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