Etching-resistant ArF photoresist and preparation method thereof

Abstract

The invention belongs to the technical field of photoresist materials, and particularly relates to an etching-resistant ArF photoresist and a preparation method thereof. The etching-resistant ArF photoresist is prepared from the following raw materials in parts by weight: 90 to 100 parts of film-forming resin, 5 to 15 parts of a photoacid generator, 0.5 to 2 parts of organic alkali, 3 to 10 parts of an etching-resistant additive and 3000 to 5000 parts of a photoresist solvent, and the etching-resistant additive is a cholic acid derivative; the film-forming resin comprises metacrylic acid ester with a side chain containing lactone, metacrylic acid ester with a side chain containing an aliphatic ring protecting group and metacrylic acid ester with a side chain containing a polar group; according to the etching-resistant ArF photoresist disclosed by the invention, the photoresist with a relatively high-resolution pattern can be formed; the photoresist has high resolution and etching resistance, and the application range of the photoresist can be widened.

Description

Technical Field

[0001] The present application belongs to the technical field of photoresist materials, and in particular relates to an etching-resistant ArF photoresist and a preparation method thereof. Background Art

[0002] The progress of photolithography technology and photolithography materials is an important factor in promoting the development of the semiconductor industry. With the continuous improvement of the integration of integrated circuits, according to the Relay formula, the resolution of photoresist is inversely proportional to the exposure wavelength, so reducing the exposure wavelength has become the main way to improve the resolution. The resolution of photoresist has developed from micrometers and submicrometers to nanometers, which requires the wavelength of the exposure light source to be continuously reduced, and at the same time, the photoresist has a higher transmittance in the corresponding wavelength band. According to the different photolithography accuracy and light source wavelength, photoresist can be divided into g-line photoresist, i-line photoresist, KrF photoresist, ArF photoresist and EUV photoresist. Among them, the light source wavelength of ArF photoresist is 193nm, which belongs to deep ultraviolet photoresist. Due to its high photolithography accuracy, this photoresist is the dominant photolithography process of advanced processes. Combined with multiple exposure processes, the resolution covers 90-7nm. With the development of high-end processes, the demand for ArF photoresist is increasing.

[0003] At present, the commercial photoresist materials independently developed by my country mainly include phenolic resin, poly(p-hydroxystyrene), etc., which are mainly used in G-line (436nm) and I-line (365nm) photolithography processes. This type of photoresist material has the disadvantages of low photosensitivity when used in the 193nm process, low graphic resolution, poor etching resistance, poor etching uniformity due to different etching rates, and poor graphic contrast. The domestic substitution rate of ArF photoresist is low. Therefore, how to design and develop ArF photoresist with high sensitivity, high etching resistance, thermal stability and good storage performance is the focus of current photoresist product development, which is of great significance to the improvement of the comprehensive performance of photoresist. Summary of the invention

[0004] In order to overcome the defect of insufficient etching resistance of ArF photoresist in the prior art, the present application provides an etching-resistant ArF photoresist and a preparation method thereof.

[0005] In a first aspect, the present application provides an etch-resistant ArF photoresist and a preparation method thereof, which adopts the following technical solution: An etching-resistant ArF photoresist comprises the following raw materials in parts by weight: 90-100 parts of a film-forming resin, 5-15 parts of a photoacid generator, 0.5-2 parts of an organic base, 3-10 parts of an etching-resistant additive, and 3000-5000 parts of a photoresist solvent, wherein the etching-resistant additive is a bile acid derivative; the film-forming resin comprises methacrylate containing lactone in the side chain, methacrylate containing aliphatic ring protecting groups in the side chain, and methacrylate containing polar groups in the side chain.

[0006] By adopting the above technical scheme, by adding a methacrylate film-forming resin containing a side chain and an aliphatic ring protecting group, the photoresist has better photosensitivity and improves the resolution of the photolithographic pattern; the composition and structure of different side chains can enhance the etching resistance of the photoresist, and can be used for ArF photoresist, wherein, by using the methacrylate with a side chain lactone and an aliphatic ring protecting group, not only can the carbon content of the side chain group be increased to improve the etching resistance of the film-forming resin, but the lactone ring can be hydrolyzed and opened in an alkaline environment, which can improve the solubility of the developer, improve the photosensitivity, and enhance the resolution; after acidification, the lactone ring can be closed, so as to enhance the cross-linking degree of the film-forming resin and improve the stability and etching performance of the photoresist. On this basis, the resin with a side chain polar group can react with a bile acid derivative and the like to further improve the adhesion of the photoresist, reduce the roughness of the surface of the photoresist pattern, and improve the resolution and etching resistance.

[0007] By introducing cholic acid derivatives into film-forming resins, steric hindrance can be further improved, and the density and etching resistance of photoresists can be improved. The cholic acid group can also reduce the diffusion rate of acid, thereby improving the uniformity of the development process, so that the ester structure of the high-carbon film-forming resin decomposes under the action of acid, improving the acid sensitivity, leaving no residue after exposure, reducing the edge roughness of the pattern, and thus improving the resolution of the photolithographic pattern. When used in conjunction with photoresist raw materials, the light transmittance of the photoresist exposure can be increased. When used in conjunction with photoacid generators, the photolithography rate, sensitivity and resolution of the photoresist can be significantly improved.

[0008] In a specific embodiment, the molar percentages of the methacrylate containing lactone on the side chain, the methacrylate containing aliphatic ring protecting group on the side chain and the methacrylate containing polar group on the side chain are (40-53):(40-27):20.

[0009] By adopting the above technical scheme, the present application discloses the ratio of methacrylate containing lactone in the side chain, aliphatic ring protecting group in the side chain, and polar group in the side chain, thereby further improving the photolithographic performance and etching resistance of the photoresist. The methacrylate containing aliphatic ring protecting group in the side chain can be decomposed into carboxyl group under acid catalysis, and the exposed photoresist resin is dissolved in the developer, thereby increasing the developing speed, greatly improving the resolution without affecting the etching performance, and then combining with the methacrylate resin with polar group, so that a large number of hydrophilic polar groups are introduced into the system, which can further adjust the structure and steric hindrance of the resin, improve the solubility of the resin and the uniformity of the developer, thereby increasing the storage time of the photoresist, and can also enhance the adhesion between the photoresist and the wafer, thereby enhancing the etching resistance.

[0010] If the content of methacrylate containing lactone is too low, the adhesion of the photoresist will be reduced. If the content is too high, the etching performance will be poor and the etching rate will be reduced. If the content of methacrylate containing aliphatic ring protecting groups is too low, the etching stability will be reduced to a certain extent, thereby affecting the resolution of the etched pattern and increasing the roughness of the pattern after etching. If the content of methacrylate containing polar groups in the side chain is too low, the adhesion to the wafer will be reduced, and the interaction performance with the etching resistance additive will be poor, which will reduce the etching resistance.

[0011] In a specific embodiment, the bile acid derivative is one or more of bile acid, lithocholic acid, and deoxycholic acid.

[0012] The mass ratio of the bile acid derivative to the film-forming resin is 1:(10-25).

[0013] By adopting the above technical scheme, the bile acid derivatives can be combined with the film-forming resin through the rigid concave structure of the steroid nucleus, the high stability and the reactivity of the side chains, the amphiphilic acidity and alkalinity, etc., to improve the stability and heat resistance of the film-forming resin. The bile acid group is introduced to improve the steric hindrance of the side chain, which can play a plasticizing role, improve the adhesion of the photoresist, and reduce the diffusion rate of the acid, thereby reducing the edge roughness of the pattern after etching. The side chain derivatives with rich reactivity can also form intermolecular forces with the photoacid generator to increase the etching resistance of the photoresist.

[0014] In a specific embodiment, the photoacid generator is one or more of diazonium salts, sulfonium salts, iodonium salts, sulfonyldiazomethane, N-hydroxyimide sulfonate, imide sulfonate, nitrobenzylbenzenesulfonate, and sulfonic acid oxime esters.

[0015] Preferably, the photoacid generator is 2-(adamantane-1-carbonyl)oxy)-1,1-difluoroethanesulfonic acid (4-methylphenyl) diphenylsulfonium salt, 4-methoxyphenylphenyl iodonium trifluoromethanesulfonate, bis(4-tert-butylphenyl) iodonium trifluoromethanesulfonate, bis(4-tert-butylphenyl) iodonium perfluoro-1-butanesulfonate, bis(4-tert-butylphenyl) iodonium camphorsulfonate, bis(4-tert-butylphenyl) iodonium perfluorooctanesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium triphenylsulfonium perfluoro-1-butanesulfonate, triphenylsulfonium perfluorooctanesulfonate, 4-methoxyphenylphenyliodonium trifluoromethanesulfonate, p-tolyldiphenylsulfonium trifluoromethanesulfonate, p-tolyldiphenylsulfonium perfluorooctanesulfonate, p-tolyldiphenylsulfonium perfluoro-1-butanesulfonate, p-tolyldiphenylsulfonium camphorsulfonate, 2,4,6-trimethylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-tert-butylphenyldiphenylsulfonium trifluoromethanesulfonate, 1-(2-naphthoylmethyl)thiolate trifluoromethanesulfonate, 4-hydroxy-1-naphthyldimethylsulfonium trifluoromethanesulfonate, N-(phenylsulfonyloxy)succinimide, N-(trifluoromethylsulfonyloxy)succinimide, N-(perfluoro-1-butanesulfonic acid)succinimide, N-(perfluorooctanesulfonic acid)succinimide, N-(trifluoromethylsulfonyloxy)phthalimide, N-(perfluorooctanesulfonic acid)phthalimide, N-(trifluoromethylsulfonyloxy) -5-norbornene-2,3-dicarboxylic acid imide, N-(perfluoro-1-butanesulfonic acid)-5-norbornene-2,3-dicarboxylic acid imide, N-(perfluorooctanesulfonic acid)-5-norbornene-2,3-dicarboxylic acid imide, N-(trifluoromethylsulfonyloxy)naphthyl methaneimide, N-(perfluoro-1-butanesulfonic acid)naphthyl methaneimide, N-(perfluorooctanesulfonic acid)naphthyl methaneimide, any one or more of N-(10-camphorsulfonyloxy)naphthyl methaneimide.

[0016] By adopting the above technical scheme, the photoacid generator selects diazo and sulfonate, which have abundant lone pair electrons around the film-forming resin. During the exposure process, the electrons are transferred, which can also improve the sensitivity of the film-forming resin to short-wave light and improve the photolithography accuracy of the photoresist.

[0017] In a specific embodiment, the organic base is one or more of tetra-n-butylammonium hydroxide, tetra-butylammonium acetate, tri-n-octylamine, 2,6-diisopropylaniline, and triethanolamine.

[0018] In a specific embodiment, the photoresist solvent is one or more of propylene glycol methyl ether acetate, ethyl lactate, ethyl acetate, 2-heptanone, ethylene glycol monomethyl ether acetate, cyclohexanone, methyl pentanol, γ-butyrolactone, and 3-ethoxypropionic acid.

[0019] By adopting the above technical scheme, the organic base can adjust the photosensitivity, accelerate the chemical reaction, and improve the reaction rate and yield. The photoresist solvent can increase the dissolution rate of each component in the photoresist raw material, thereby improving the development speed of the photoresist and the storage stability of the photoresist.

[0020] In a second aspect, the present application provides a method for preparing an etch-resistant ArF photoresist, which adopts the following technical scheme: a method for preparing an etch-resistant ArF photoresist, comprising the following steps: heating the photoresist solvent to 30-50°C in proportion, then adding a film-forming resin and an etch-resistant additive, stirring and mixing, adding a photoacid generator and an organic base, and continuously stirring and mixing to obtain a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1-0.3μm to obtain a finished photoresist.

[0021] The stirring and mixing conditions are 300-500 rpm and the stirring time is 2-4 hours.

[0022] In summary, the present application includes at least one of the following beneficial technical effects: 1. By adding a methacrylate film-forming resin containing a side chain, the photoresist has better photosensitivity and improves the resolution of the photolithographic pattern; the composition and structure of different side chains can enhance the etching resistance of the photoresist and can be used for ArF photoresist, wherein, by using methacrylate with side chain lactone and aliphatic ring protecting group, not only can the carbon content of the side chain group be increased to improve the etching resistance of the film-forming resin, but also the lactone ring can be hydrolyzed and opened in an alkaline environment, which can improve the solubility of the developer, improve the photosensitivity, and enhance the resolution; after acidification, the lactone ring can be closed, so as to enhance the cross-linking degree of the film-forming resin and improve the stability and etching performance of the photoresist. On this basis, the resin with side chain polar groups can react with bile acid derivatives, etc., to further improve the adhesion of the photoresist, reduce the roughness of the surface of the photoresist pattern, and improve the resolution and etching resistance.

[0023] By introducing cholic acid derivatives into film-forming resins, steric hindrance can be further increased, the density and etching resistance of photoresists can be improved, and the cholic acid group can also reduce the diffusion rate of acid, thereby improving the uniformity of the development process, reducing the edge roughness of the pattern, and thus improving the resolution of the photolithographic pattern. When used in conjunction with photoresist raw materials, the light transmittance of the photoresist exposure can be increased. When used in conjunction with photoacid generators, the photolithography rate, sensitivity and resolution of the photoresist can be significantly improved.

[0024] 2. The present application discloses the ratio of methacrylate containing lactone in the side chain, aliphatic ring protecting group in the side chain, and polar group in the side chain, thereby further improving the photolithographic performance and etching resistance of the photoresist. The methacrylate resin containing lactone in the side chain provides a skeleton effect during the acidification process to improve the steric hindrance, reduce the shrinkage rate of the photoresist, and improve the resolution; and the methacrylate containing aliphatic ring in the side chain can be decomposed into carboxyl groups under acid catalysis, and the exposed photoresist resin is dissolved in the developer, thereby increasing the development speed, greatly improving the resolution without affecting the etching performance, and combining with the methacrylate resin with polar groups, so that a large number of hydrophilic polar groups are introduced into the system, which can further adjust the structure and steric hindrance of the resin, improve the solubility of the resin and the uniformity of the developer, thereby increasing the storage time of the photoresist, and can also enhance the adhesion between the photoresist and the wafer, thereby enhancing the etching resistance. DETAILED DESCRIPTION

[0025] Some of the raw materials used in the preparation examples and embodiments: 2-Carboxyl-4-norbornyl lactone-5-methacrylate: purchased from Shanghai Qiaomu Chemical Technology Co., Ltd.; 2-Carbonyl-tetrahydrofuran-3-hydroxy-methacrylate was purchased from Jiangsu Pules Biotechnology Co., Ltd.; triphenylsulfonium chloride was purchased from Shanghai Mairui Biochemical Technology Co., Ltd.; The raw materials used in the examples and comparative examples that are not otherwise specified are all conventional products that can be purchased from the market. Example

[0026] Example 1 An etch-resistant ArF photoresist comprises the following raw materials in parts by weight: 4 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, 0.2 g of an etch-resistant additive, and 150 g of a photoresist solvent, wherein the etch-resistant additive is bile acid; the film-forming resin is 2-carbonyl-tetrahydrofuran-3-hydroxy-methylacrylate, 2-methyl-2-adamantyl methacrylate, and 3-hydroxy-1-adamantyl methacrylate in a molar mass ratio of 45:35:20; the photoacid generator is triphenylsulfonium chloride, and the organic base is trioctylamine; the photoresist solvent is propylene glycol methyl ether acetate; The preparation method comprises the following steps: heating a photoresist solvent to 30° C. in proportion, then adding a film-forming resin and an etching-resistant additive, stirring for 4 hours at a speed of 300 rpm to mix evenly; then adding a photoacid generator and an organic base, continuously stirring for 2 hours to obtain a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0027] Example 2 An etch-resistant ArF photoresist comprises the following raw materials in parts by weight: 4 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, 0.2 g of an etch-resistant additive, and 150 g of a photoresist solvent, wherein the etch-resistant additive is lithocholic acid; the film-forming resin is 2-carboxy-4-norbornyl lactone-5-methylacrylate, 2-methyl-2-adamantyl methacrylate, and 3-hydroxy-1-adamantyl methacrylate in a molar mass ratio of 40:40:20; the photoacid generator is triphenylsulfonium chloride, and the organic base is triethanolamine; and the photoresist solvent is ethyl lactate; The preparation method comprises the following steps: heating a photoresist solvent to 50° C. in proportion, then adding a film-forming resin and an etching-resistant additive, stirring at a speed of 500 rpm for 2 hours, and mixing evenly; then adding a photoacid generator and an organic base, continuously stirring for 2 hours, obtaining a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0028] Example 3 An etch-resistant ArF photoresist comprises the following raw materials in parts by weight: 4 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, 0.2 g of an etch-resistant additive, and 150 g of a photoresist solvent, wherein the etch-resistant additive is deoxycholic acid; the film-forming resin is 2-carboxy-4-norbornyl lactone-5-methylacrylate, 1-methylcyclopentyl methacrylate, and 3-hydroxy-1-adamantyl methacrylate in a molar mass ratio of 53:27:20; the photoacid generator is triphenylsulfonium chloride, and the organic base is triethanolamine; and the photoresist solvent is ethyl lactate; The preparation method comprises the following steps: heating a photoresist solvent to 50° C. in proportion, then adding a film-forming resin and an etching-resistant additive, stirring at a speed of 500 rpm for 2 hours, and mixing evenly; then adding a photoacid generator and an organic base, continuously stirring for 2 hours, obtaining a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0029] Example 4 An etch-resistant ArF photoresist comprises the following raw materials in parts by weight: 4 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, 0.2 g of an etch-resistant additive, and 150 g of a photoresist solvent, wherein the etch-resistant additive is deoxycholic acid; the film-forming resin is 2-carboxy-4-norbornyl lactone-5-methylacrylate, 1-methylcyclopentyl methacrylate, and 3-hydroxy-1-adamantyl methacrylate in a molar mass ratio of 35:27:38; the photoacid generator is triphenylsulfonium chloride, and the organic base is triethanolamine; and the photoresist solvent is ethyl lactate; The preparation method comprises the following steps: heating a photoresist solvent to 50° C. in proportion, then adding a film-forming resin and an etching-resistant additive, stirring at a speed of 500 rpm for 2 hours, and mixing evenly; then adding a photoacid generator and an organic base, continuously stirring for 2 hours, obtaining a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0030] Example 5 An etch-resistant ArF photoresist comprises the following raw materials in parts by weight: 4 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, 0.2 g of an etch-resistant additive, and 150 g of a photoresist solvent, wherein the etch-resistant additive is deoxycholic acid; the film-forming resin is 2-carboxy-4-norbornyl lactone-5-methylacrylate, 1-methylcyclopentyl methacrylate, and 3-hydroxy-1-adamantyl methacrylate in a molar mass ratio of 53:24:23; the photoacid generator is triphenylsulfonium chloride, and the organic base is triethanolamine; and the photoresist solvent is ethyl lactate; The preparation method comprises the following steps: heating a photoresist solvent to 50° C. in proportion, then adding a film-forming resin and an etching-resistant additive, stirring at a speed of 500 rpm for 2 hours, and mixing evenly; then adding a photoacid generator and an organic base, continuously stirring for 2 hours, obtaining a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0031] Example 6 An etch-resistant ArF photoresist comprises the following raw materials in parts by weight: 4 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, 0.2 g of an etch-resistant additive, and 150 g of a photoresist solvent, wherein the etch-resistant additive is deoxycholic acid; the film-forming resin is 2-carboxy-4-norbornyl lactone-5-methylacrylate, 1-methylcyclopentyl methacrylate, and 3-hydroxy-1-adamantyl methacrylate in a molar mass ratio of 53:32:15; the photoacid generator is triphenylsulfonium chloride, and the organic base is triethanolamine; and the photoresist solvent is ethyl lactate; The preparation method comprises the following steps: heating a photoresist solvent to 50° C. in proportion, then adding a film-forming resin and an etching-resistant additive, stirring at a speed of 500 rpm for 2 hours, and mixing evenly; then adding a photoacid generator and an organic base, continuously stirring for 2 hours, obtaining a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0032] Example 7 An etch-resistant ArF photoresist comprises the following raw materials in parts by weight: 4.05 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, 0.15 g of an etch-resistant additive, and 150 g of a photoresist solvent, wherein the etch-resistant additive is deoxycholic acid; the film-forming resin is 2-carboxy-4-norbornyl lactone-5-methylacrylate, 1-methylcyclopentyl methacrylate, and 3-hydroxy-1-adamantyl methacrylate in a molar mass ratio of 53:27:20; the photoacid generator is triphenylsulfonium chloride, and the organic base is triethanolamine; and the photoresist solvent is ethyl lactate; The preparation method comprises the following steps: heating a photoresist solvent to 50° C. in proportion, then adding a film-forming resin and an etching-resistant additive, stirring at a speed of 500 rpm for 2 hours, and mixing evenly; then adding a photoacid generator and an organic base, continuously stirring for 2 hours, obtaining a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0033] Example 8 An etch-resistant ArF photoresist comprises the following raw materials in parts by weight: 3.75 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, 0.45 g of an etch-resistant additive, and 150 g of a photoresist solvent, wherein the etch-resistant additive is deoxycholic acid; the film-forming resin is 2-carboxy-4-norbornyl lactone-5-methylacrylate, 1-methylcyclopentyl methacrylate, and 3-hydroxy-1-adamantyl methacrylate in a molar mass ratio of 53:27:20; the photoacid generator is triphenylsulfonium chloride, and the organic base is triethanolamine; and the photoresist solvent is ethyl lactate; The preparation method comprises the following steps: heating a photoresist solvent to 50° C. in proportion, then adding a film-forming resin and an etching-resistant additive, stirring at a speed of 500 rpm for 2 hours, and mixing evenly; then adding a photoacid generator and an organic base, continuously stirring for 2 hours, obtaining a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0034] Comparative Example 1 An etch-resistant ArF photoresist comprises the following raw materials in parts by weight: 4 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, 0.2 g of an etch-resistant additive, and 150 g of a photoresist solvent, wherein the etch-resistant additive is deoxycholic acid; the film-forming resin is 2-carboxy-4-norbornyl lactone-5-methylacrylate and 1-methylcyclopentyl methacrylate in a molar mass ratio of 53:47; the photoacid generator is triphenylsulfonium chloride, and the organic base is triethanolamine; and the photoresist solvent is ethyl lactate; The preparation method comprises the following steps: heating a photoresist solvent to 50° C. in proportion, then adding a film-forming resin and an etching-resistant additive, stirring at a speed of 500 rpm for 2 hours, and mixing evenly; then adding a photoacid generator and an organic base, continuously stirring for 2 hours, obtaining a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0035] Comparative Example 2 An etch-resistant ArF photoresist comprises the following raw materials in parts by weight: 4 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, 0.2 g of an etch-resistant additive, and 150 g of a photoresist solvent, wherein the etch-resistant additive is deoxycholic acid; the film-forming resin is 2-carboxyl-4-norbornyl lactone-5-methylacrylate and 3-hydroxy-1-adamantyl methacrylate in a molar mass ratio of 53:47; the photoacid generator is triphenylsulfonium chloride, and the organic base is triethanolamine; and the photoresist solvent is ethyl lactate; The preparation method comprises the following steps: heating a photoresist solvent to 50° C. in proportion, then adding a film-forming resin and an etching-resistant additive, stirring at a speed of 500 rpm for 2 hours, and mixing evenly; then adding a photoacid generator and an organic base, continuously stirring for 2 hours, obtaining a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0036] Comparative Example 3 The invention discloses an ArF photoresist resistant to etching, comprising the following raw materials in parts by weight: 4 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, 0.2 g of an etching-resistant additive, and 150 g of a photoresist solvent, wherein the etching-resistant additive is deoxycholic acid; the film-forming resin is 1-methylcyclopentyl methacrylate and 3-hydroxy-1-adamantyl methacrylate in a molar mass ratio of 80:20; the photoacid generator is triphenylsulfonium chloride, and the organic base is triethanolamine; the photoresist solvent is ethyl lactate; and the preparation method comprises the following steps: heating the photoresist solvent to 50° C. in proportion, then adding the film-forming resin and the etching-resistant additive, stirring at a speed of 500 rpm for 2 hours to mix evenly; then adding the photoacid generator and the organic base, stirring continuously for 2 hours to obtain a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0037] Comparative Example 4 An etch-resistant ArF photoresist comprises the following raw materials in parts by weight: 4 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, 0.2 g of an etch-resistant additive, and 150 g of a photoresist solvent, wherein the etch-resistant additive is deoxycholic acid; the film-forming resin is 2-carboxy-4-norbornyl lactone-5-methylacrylate; the photoacid generator is triphenylsulfonium chloride, the organic base is triethanolamine; and the photoresist solvent is ethyl lactate; The preparation method comprises the following steps: heating a photoresist solvent to 50° C. in proportion, then adding a film-forming resin and an etching-resistant additive, stirring at a speed of 500 rpm for 2 hours, and mixing evenly; then adding a photoacid generator and an organic base, continuously stirring for 2 hours, obtaining a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0038] Comparative Example 5 An etch-resistant ArF photoresist comprises the following raw materials in parts by weight: 4 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, 0.2 g of an etch-resistant additive, and 150 g of a photoresist solvent, wherein the etch-resistant additive is deoxycholic acid; the film-forming resin is 1-methylcyclopentyl methacrylate; the photoacid generator is triphenylsulfonium chloride, the organic base is triethanolamine; and the photoresist solvent is ethyl lactate; The preparation method comprises the following steps: heating a photoresist solvent to 50° C. in proportion, then adding a film-forming resin and an etching-resistant additive, stirring at a speed of 500 rpm for 2 hours, and mixing evenly; then adding a photoacid generator and an organic base, continuously stirring for 2 hours, obtaining a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0039] Comparative Example 6 An etch-resistant ArF photoresist comprises the following raw materials in parts by weight: 4 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, 0.2 g of an etch-resistant additive, and 150 g of a photoresist solvent, wherein the etch-resistant additive is deoxycholic acid; the film-forming resin is 3-hydroxy-1-adamantyl methacrylate; the photoacid generator is triphenylsulfonium chloride, the organic base is triethanolamine; and the photoresist solvent is ethyl lactate; The preparation method comprises the following steps: heating a photoresist solvent to 50° C. in proportion, then adding a film-forming resin and an etching-resistant additive, stirring at a speed of 500 rpm for 2 hours, and mixing evenly; then adding a photoacid generator and an organic base, continuously stirring for 2 hours, obtaining a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0040] Comparative Example 7 An etch-resistant ArF photoresist comprises the following raw materials in parts by weight: 4.2 g of a film-forming resin, 0.3 g of a photoacid generator, 0.05 g of an organic base, and 150 g of a photoresist solvent, wherein the film-forming resin is 2-carboxy-4-norbornyl lactone-5-methylacrylate, 1-methylcyclopentyl methacrylate, and 3-hydroxy-1-adamantyl methacrylate in a molar mass ratio of 53:27:20; the photoacid generator is triphenylsulfonium chloride, and the organic base is triethanolamine; and the photoresist solvent is ethyl lactate; The preparation method comprises the following steps: heating a photoresist solvent to 50° C. in proportion, then adding a film-forming resin, stirring at a speed of 500 rpm for 2 hours, and mixing evenly; then adding a photoacid generator and an organic base, continuously stirring for 2 hours, obtaining a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1 μm to obtain a finished photoresist.

[0041] Performance Testing The photoresist performance test of the embodiment and comparative example was carried out by the following method: The ArF photoresists obtained in the embodiments and comparative examples were respectively spin-coated on different test pieces with anti-reflection layers using an ACT-8 spin coater at a spin coating speed of 1000 r / min, and then baked at 110°C for 150s. After cooling to room temperature, the thickness of the photoresist film layer was measured. The test pieces were then placed in a LAM EXELAN HPT etching machine and etched for 20s under the process conditions of 60Mt / 1000W / 500W / 45CF4 / 180Ar / 10002, and the thickness of the remaining photoresist film layer was measured and the etching rate of the film layer was calculated.

[0042] Resolution method: Use a scanning electron microscope to examine the photoresist pattern to compare the resolution of the photoresist. The resolution is based on the minimum achievable line width. The smaller the line width, the higher the resolution, which is expressed as the minimum feature size observed; Adhesion: The adhesion was observed using scanning electron microscopy.

[0043] The test results are shown in Table 1: Table 1 Performance test results The etch-resistant ArF photoresist obtained in Examples 1-8 has good performance, high resolution and excellent anti-dry etching performance. The etch-resistant ArF photoresist obtained in the examples has uniform independent line edges, and no peeling and glue inversion occurs. The minimum line width that can be separated by the photoresist obtained in each example is no more than 100nm, showing good photolithography accuracy. At the same time, the etching speed of the photoresist obtained in each example of the present application is no more than Shows ideal etch resistance.

[0044] By comparing Examples 3-6 and Comparative Examples 1-6, it can be seen that the composition and structure of different side chains can enhance the etching resistance of the photoresist and can be used for ArF photoresist. The methyl acrylate of the side chain lactone and the aliphatic ring protecting group can not only increase the carbon content of the side chain group to improve the etching resistance of the film-forming resin, but also the lactone ring can be hydrolyzed and opened in an alkaline environment, which can improve the solubility of the developer, improve the photosensitivity, and enhance the resolution; after acidification, the lactone ring can be closed again, thereby enhancing the cross-linking degree of the film-forming resin and improving the stability and etching performance of the photoresist. On this basis, the resin with side chain polar groups can react with bile acid derivatives, etc. to further improve the adhesion of the photoresist, reduce the roughness of the surface of the photoresist pattern, and improve the resolution and etching resistance. If the content of lactone-containing methacrylate resin is too low, the adhesion is poor. If the content is too high, the etching uniformity is poor and the etching rate is reduced. If the content of methacrylate with aliphatic ring protecting group is too low, the etching stability can be reduced to a certain extent, thereby affecting the resolution of the etched pattern and increasing the roughness of the pattern after etching. If the content of methacrylate with polar groups in the side chain is too low, the adhesion to the wafer can be reduced, thereby reducing the etching resistance.

[0045] By comparing Example 3 with Examples 7-8 and Comparative Example 7, it can be seen that the performance of the photoresist prepared in Example 3 is better than that of Examples 7-8. Analysis shows that the rigid concave structure of the steroid nucleus of the cholic acid derivative, the high stability and the reactivity of the side chains, the amphiphilic acidity and alkalinity, etc., can be combined with the film-forming resin to improve the stability and heat resistance of the film-forming resin, and the introduction of cholic acid groups to improve the steric hindrance of the side chains can play a plasticizing role, improve the adhesion of the photoresist, and reduce the diffusion rate of the acid, thereby reducing the edge roughness of the pattern after etching and improving the etching efficiency. The side-chain derivatives with rich reactivity can also form intermolecular forces with the photoacid generator to increase the etching resistance of the photoresist.

[0046] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An ArF photoresist resistant to etching, characterized in that: The invention comprises the following raw materials in parts by weight: 90-100 parts of film-forming resin, 5-15 parts of photoacid generator, 0.5-2 parts of organic base, 3-10 parts of etching resistance additive and 3000-5000 parts of photoresist solvent, wherein the etching resistance additive is a bile acid derivative; the film-forming resin comprises methacrylate containing lactone in the side chain, methacrylate containing aliphatic ring protecting group in the side chain and methacrylate containing polar group in the side chain.

2. The etching-resistant ArF photoresist according to claim 1, characterized in that: The molar percentages of the methacrylate containing lactone on the side chain, the methacrylate containing aliphatic ring protecting groups on the side chain and the methacrylate containing polar groups on the side chain are (40-53):(40-27):

20.

3. The etching-resistant ArF photoresist according to claim 1, characterized in that: The bile acid derivative is one or more of bile acid, lithocholic acid and deoxycholic acid.

4. The etching-resistant ArF photoresist according to claim 1, characterized in that: The photoacid generator is one or more of diazonium salt, sulfonium salt, iodonium salt, sulfonyldiazomethane, N-hydroxyimide sulfonate, imide sulfonate, nitrobenzylbenzenesulfonate, and sulfonic acid oxime ester.

5. The etching-resistant ArF photoresist according to claim 1, characterized in that: The organic base is one or more of tetra-n-butylammonium hydroxide, tetra-butylammonium acetate, tri-n-octylamine, 2,6-diisopropylaniline and triethanolamine.

6. The etching-resistant ArF photoresist according to claim 1, characterized in that: The photoresist solvent is one or more of propylene glycol methyl ether acetate, ethyl lactate, ethyl acetate, 2-heptanone, ethylene glycol monomethyl ether acetate, cyclohexanone, methyl pentanol, γ-butyrolactone, and 3-ethoxypropionic acid.

7. The method for preparing the etching-resistant ArF photoresist according to claims 1-6, characterized in that: The method comprises the following steps: heating a photoresist solvent to 30-50° C. in proportion, then adding a film-forming resin and an etching-resistant additive, stirring and mixing, adding a photoacid generator and an organic base, continuously stirring and mixing to obtain a crude photoresist, and then filtering through a polytetrafluoroethylene membrane with a pore size of 0.1-0.3 μm to obtain a finished photoresist.

8. The method for preparing the etching-resistant ArF photoresist according to claim 7, characterized in that: The stirring and mixing conditions are 300-500 rpm and the stirring time is 2-4 hours.

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