A pag key type photosensitive photoresist resin and a preparation method thereof

Abstract

The application discloses a PAG bonding type photosensitive photoresist resin and a preparation method and application thereof. The photoresist resin is as follows: formula. The PAG bonding type resin is prepared through the following reaction process: 1) performing a RAFT polymerization reaction on p-acetoxystyrene, p-styrene sulfonamide trifluoromethyl potassium salt and a RAFT chain transfer agent under the action of an initiator to obtain an intermediate I, 2) performing a hydrolysis reaction on the intermediate I to obtain an intermediate II, 3) performing a protection group introduction reaction on the intermediate II and di-tert-butyl dicarbonate to obtain an intermediate III; and 4) performing an ion exchange reaction on the intermediate III and triphenylsulfonium bromide. The application realizes the bonding of the PAG into the resin skeleton, and improves the problems of poor compatibility between the PAG and the resin, phase separation, uneven distribution of the PAG and the like. Therefore, the photoresist prepared from the resin has the photo-generated acid bound by the polymer main chain and limited diffusion, the resolution is improved, and the photoetching effect is excellent.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of photolithography in microfabrication, in particular to the field of photosensitive photoresist resin, preparation method and application in photolithography. BACKGROUND

[0002] Photolithography is a process technology that transfers the pattern on the mask to the wafer by using the photochemical reaction principle and chemical and physical etching methods of photoresist. Photoresist, also known as photoresist, is a kind of etching-resistant photosensitive material whose solubility changes significantly after irradiation or radiation by ultraviolet light, electron beam, etc. Photolithography is an important factor in limiting the size of integrated circuit devices, and photoresist materials play a decisive role in realizing the next generation of photolithography.

[0003] According to the chemical reaction mechanism, photoresist can be divided into two categories: positive photoresist and negative photoresist. Positive photoresist refers to a photoresist in which the exposed part is dissolved in the developing solution and the unexposed part remains to form an image after exposure and development in the photolithography process; negative photoresist is the opposite of positive photoresist, in which the unexposed part is dissolved, and the exposed part forms an image.

[0004] The resolution of traditional photolithography follows the Rayleigh formula: d = kλ / NA, where d is the minimum line width of photolithography, k is the process coefficient, λ is the exposure wavelength in the photolithography process, and NA is the aperture size. The minimum line width in the traditional photolithography process can be improved by increasing the lens aperture of the photolithography equipment or by reducing the exposure wavelength used in the photolithography process. According to the wavelength of the exposure light source, photoresist can be divided into ultraviolet, deep ultraviolet and extreme ultraviolet photoresist.

[0005] Compared with ultraviolet light, the intensity of deep ultraviolet light is lower, and in order to meet the photosensitivity requirements, deep ultraviolet photoresist is generally a chemical amplification type photoresist. The working mechanism of chemical amplification type photoresist is that during the exposure process, the photoacid generator decomposes to produce acid, and in the post-baking process, the acid catalyzes the chemical reaction of the acid-labile groups in the polymer resin, and the catalytic reaction releases the acid again to continue to catalyze the reaction of other acid-labile groups, until all the acid-labile groups in the polymer resin in the exposed area are completely removed. Therefore, a small amount of photoacid generator can make all the acid-labile groups of the polymer resin be removed after exposure, so that the solubility of the polymer resin in the developing solution changes, achieving the effect of chemical amplification. Thus reducing the requirements for the content of photoacid generator in the photoresist and the exposure energy.

[0006] Chemical amplification photoresist is mainly composed of polymer resin, photoacid generator and solvent. The polymer resin as the skeleton of photoresist determines the basic properties of photoresist such as hardness, flexibility, adhesion, etc.; the photoacid generator (PAG) generates a small amount of acid in the exposure process to cause deprotection reaction with the main resin, thereby increasing the solubility difference between the exposed area and the non-exposed area in the developing solution; the solvent is the largest component in the photoresist, which makes the photoresist in liquid state and has little influence on the chemical properties of the photoresist.

[0007] The traditional photoresist system is a PAG and polymer resin blending system. Since PAG is usually a small molecule compound, there is an inherent incompatibility between PAG and polymer resin, which may cause problems such as phase separation, uneven distribution of PAG in the photoresist film, segregation of PAG to the upper layer of the photoresist film during pre-baking, and photo-generated acid migration during post-baking, thereby causing uneven acid-catalyzed photochemical reaction in the exposed area, resulting in larger line edge roughness of the photoetching pattern and lower resolution. The photoresist polymer resin is mainly synthesized by traditional free radical polymerization, and the traditional free radical polymerization is prone to free radical coupling, disproportionation, chain transfer and other side reactions during polymerization. In addition, due to the large difference in reactivity between PAG and other monomers, the composition and molecular weight of the synthesized polymer are difficult to control. SUMMARY

[0008] In order to overcome the above problems, the present application provides a PAG-attached photoresist resin and a preparation method thereof. The photoresist prepared by using the PAG-attached photoresist resin of the present application has excellent photoetching effect.

[0009] The present application is achieved by the following technical solutions.

[0010] The present application first provides a PAG-attached photoresist resin, whose structural formula is as follows:

[0011]

[0012] In the formula, x:y:z=(1-70):(20-80):(1-30).

[0013] The present application further provides a preparation method of the above-mentioned PAG-attached photoresist resin, and the synthetic route of the preparation method is as follows:

[0014]

[0015] In the formula, n=x+y; n:z=(2-99):1, x:y=(0.01-3.5):1.

[0016] The method comprises the following steps:

[0017] (1) Disperse p-acetoxystyrene, p-styrene sulfonamide trifluoromethyl potassium salt and a RAFT chain transfer agent in a first solvent, add an initiator to undergo a RAFT polymerization reaction, after the reaction is completed, drop the reaction solution into a second solvent, filter to obtain a solid precipitate, then disperse the solid precipitate in the first solvent, and drop the solution into a third solvent, filter and dry to obtain an intermediate I;

[0018] (2) Disperse the intermediate I and a first base in a first solvent and a second solvent to undergo a hydrolysis reaction, after the reaction is completed, add an acid to adjust the PH of the reaction solution, stand until the solution is layered, then drop the organic phase of the reaction solution into a second solvent, filter and dry to obtain an intermediate II; assuming that the molar ratio of the acetoxystyrene and the p-styrene sulfonamide trifluoromethyl potassium salt added in step (1) is n and z respectively, then the molar ratio here satisfies intermediate I: first base = 1: (n~3n);

[0019] (3) Disperse the intermediate II, a second base and di-tert-butyl dicarbonate in a first solvent to undergo a protection group introduction reaction; the molar ratio here satisfies intermediate II: second base: di-tert-butyl dicarbonate = 1: (0.05n~0.2n): (0.2~0.99n);

[0020] (4) Drop the reaction solution into a third solvent, filter to obtain a solid precipitate, then disperse the solid precipitate in a first solvent;

[0021] (5) Repeat the operation of step (4) 2 times, then drop the solution into a third solvent, filter and dry to obtain an intermediate III;

[0022] (6) Disperse the intermediate III and triphenylsulfonium bromide in a first solvent and a second solvent to undergo an ion exchange reaction, the molar ratio here satisfies intermediate III: triphenylsulfonium = 1: (z~2z);

[0023] (7) After the reaction is completed, stand until the solution is layered, wash the organic phase of the reaction solution with a second solvent 3 times;

[0024] (8) Drop the organic phase of the reaction solution into a third solvent, filter to obtain a solid precipitate, then disperse the solid precipitate in a first solvent;

[0025] (9) Repeat the operation of step (8) 2 times, then drop the solution into a third solvent, filter and dry to obtain a PAG bond type photosensitive photoresist resin.

[0026] Further, the molar ratio of p-acetoxystyrene to potassium trifluoromethylsulfonimide in step (1) is (2-99):1, the molar ratio of p-acetoxystyrene to RAFT chain transfer agent is (30-100):1, and the molar ratio of p-acetoxystyrene to initiator is (30-300):1.

[0027] Further, the RAFT chain transfer agent in step (1) is any one of 2-(((dodecylsulfanyl)thioxoacetyl)-sulfanyl)propanoic acid, 2-(dodecyltrithiocarbonato)-2-methylpropanoic acid, 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid, 4-cyano-4-(phenylcarbonylthio)pentanoic acid, 2-phenyl-2-propyl benzo dithiole, 2-cyano-2-propyl benzo dithiole, 2-cyano-2-propyl dodecyltrithiocarbonate, or ethyl 1-(methoxycarbonyl)benzodithioate.

[0028] Further, the initiator in step (1) is an azo-based radical initiator or a peroxide radical initiator, wherein the azo initiator is any one of azobis isobutyronitrile, azobis isohexyl nitrile, or dimethyl azobis isobutyrate, and the peroxide radical initiator is any one of dibenzoyl peroxide, tert-butyl hydroperoxide, or benzoic acid hydroperoxide.

[0029] Further, the first solvent is one or more of dichloromethane, trichloromethane, dioxane, tetrahydrofuran, N,N-dimethylformamide, propylene glycol methyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, ethyl acetate, ethylene glycol monomethyl ether acetate, acetone, cyclohexanone, or methanol, the second solvent is water, and the third solvent is any one of n-hexane, petroleum ether, or cyclohexane.

[0030] Further, the first base is any one of sodium hydroxide, lithium hydroxide, potassium hydroxide, or aqueous ammonia, and the second base is any one of 4-dimethylaminopyridine, lithium carbonate, calcium carbonate, sodium carbonate, potassium carbonate, potassium tert-butoxide, or sodium methoxide; and the acid used to adjust the pH of the reaction solution in step (2) is any one of hydrochloric acid, phosphoric acid, formic acid, acetic acid, or aminoacetic acid.

[0031] Further, the RAFT polymerization reaction temperature in step (1) is 40-100°C, and the reaction time is 5-24h; the hydrolysis reaction temperature in step (2) is 20-70°C, and the reaction time is 2-24h; the reaction temperature for introducing a protecting group in step (3) is 20-60°C, and the reaction time is 2-24h; and the ion exchange reaction temperature in step (6) is 20-60°C, and the reaction time is 2-24h.

[0032] The present invention also provides a photoresist, which is formed by mixing the above-mentioned PAG-bonded photosensitive photoresist resin and a solvent, wherein the mass fraction of the resin is 5%-30%. The solvent is selected from any one or more of propylene glycol methyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, ethyl acetate, ethylene glycol monomethyl ether acetate, tetrahydrofuran, acetone, cyclohexanone, N,N-dimethylformamide, or methanol.

[0033] The present invention also provides a method for forming a photolithographic pattern, wherein the above-mentioned photoresist is applied to a substrate to be photolithographically etched, such as a silicon wafer, and after pre-baking, a mask is placed on the photoresist, and after exposure, post-baking and development, the photolithographic pattern is obtained.

[0034] More specifically, the method for forming the photolithographic pattern is as follows: spin-coating the above-mentioned photoresist onto the substrate to be photolithographically etched, pre-baking at 100°C for 60 seconds, covering the baked photoresist with a mask, exposing the mask with 254nm ultraviolet light, after exposure, post-baking at 100°C for 60 seconds, and then developing in a 2.38% tetramethylammonium hydroxide developer, followed by washing away the developer with deionized water to obtain the photolithographic pattern.

[0035] The beneficial effects of this invention are mainly reflected in the following aspects.

[0036] 1. This invention prepares photoresist resin by reversible addition-fragmentation chain transfer (RAFT) polymerization. It involves adding a RAFT chain transfer agent with a high chain transfer coefficient to traditional free radical polymerization. Reversible addition-fragmentation chain transfer continuously occurs between the growing chain free radical and the dormant chain, keeping the concentration of active free radicals in the reaction system at a low level. This reduces side reactions such as coupling or disproportionation termination between molecular chains, thereby achieving controllable active free radical polymerization, controllable composition and molecular weight of the synthesized polymer, and uniform and controllable composition of the polymer resin.

[0037] 2. Furthermore, this invention also achieves the integration of PAG bonds into the resin, attaching photoacid generator (PAG) units to the photoresist polymer resin backbone, effectively improving problems such as poor compatibility between PAG and resin, phase separation, and uneven PAG distribution. Moreover, the diffusion of the photoacid generated after exposure is restricted due to the constraint of the polymer backbone, thereby reducing the edge roughness of the imaged pattern and improving the photoresist resolution. Attached Figure Description

[0038] Figure 1 The infrared spectrum of the PAG-bonded photosensitive photoresist resin in Example 1 of this invention is shown.

[0039] Figure 2 This is the 1H NMR spectrum of the PAG-bonded photosensitive photoresist resin in Example 1 of the present invention.

[0040] Figure 3 A photoresist sensitivity curve prepared for the PAG-attached type photosensitive photoresist resin in Example 1 of the present application.

[0041] Figure 4 A photoresist acid diffusion length curve prepared for the PAG-attached type photosensitive photoresist resin in Example 1 of the present application.

[0042] Figure 5 A photoresist topography optical microscope pattern obtained for the photoresist prepared for the PAG-attached type photosensitive photoresist resin in Example 1 of the present application.

[0043] Figure 6 A photoresist topography atomic force microscope pattern obtained for the photoresist prepared for the PAG-attached type photosensitive photoresist resin in Example 1 of the present application. DETAILED DESCRIPTION

[0044] The present application will be further described in the following by way of examples, but the present application is not limited to the scope of the examples. The experimental methods in the following examples, for which no specific conditions are indicated, are selected according to the conventional methods and conditions, or according to the instructions of the commercial products.

[0045] The PAG-attached type photosensitive photoresist resin is prepared according to the synthetic route of the following reaction formula in each embodiment of the present application. The preparation process mainly includes: the RAFT polymerization reaction of p-acetoxystyrene, p-styrene sulfonamide trifluoromethyl potassium salt and RAFT chain transfer agent under the action of an initiator to form intermediate I; the hydrolysis reaction of intermediate I in lye to obtain intermediate II; the introduction of a protecting group reaction of intermediate II and di-tert-butyl dicarbonate in lye to obtain intermediate III; the ion exchange reaction of intermediate III and triphenylsulfonium bromide to obtain the PAG-attached type photosensitive photoresist resin. By this method, the PAG is attached to the polymer chain, so that the generated photoacid is no longer randomly dispersed when photoetching, and the photoacid diffusion is limited within a certain distance, which is conducive to improving the photoetching resolution and reducing the edge roughness.

[0046]

[0047] The present application will be further described in the following by way of examples, but the present application is not limited to the scope of the examples. The experimental methods in the following examples, for which no specific conditions are indicated, are selected according to the conventional methods and conditions, or according to the instructions of the commercial products.

[0048] Example 1

[0049] The specific steps for preparing the PAG-attached type photosensitive photoresist resin in this embodiment are as follows:

[0050] (1) 5.42 g of p-acetoxystyrene, 2.31 g of p-styrene sulfonamide trifluoromethyl potassium salt and 0.24 g of RAFT chain transfer agent 2-(((dodecane sulfanyl)thioacetyl)-sulfanyl) propanoic acid were dispersed in 8.70 g of solvent N,N-dimethylformamide, protected by nitrogen, heated to 70°C, 0.06 g of initiator azobisisobutyronitrile dispersed in 3.30 g of N,N-dimethylformamide was added, and the reaction was carried out at 70°C for 8 h; after the reaction was completed, the reaction solution was added dropwise into 500 ml of water, and a solid precipitate was obtained by filtration, then the solid precipitate was dissolved in 50 ml of tetrahydrofuran, and then added dropwise into 500 ml of n-hexane, and the solid precipitate was obtained by filtration and dried under reduced pressure to obtain intermediate I; in this step, the addition ratio of each main material satisfies: the molar ratio of p-acetoxystyrene to p-styrene sulfonamide trifluoromethyl potassium salt is (5.10:1), the molar ratio of p-acetoxystyrene to RAFT chain transfer agent is (48:1), and the molar ratio of p-acetoxystyrene to initiator is (96:1).

[0051] (2) 5.90 g of intermediate I and 2.17 g of sodium hydroxide were dispersed in 39.0 g of tetrahydrofuran and 26.9 g of water, and the reaction was carried out at 40°C for 6 h; after the reaction was completed, hydrochloric acid was added to adjust the PH of the reaction solution to 7, and the solution was allowed to stand until the organic phase was separated, then the reaction solution was added dropwise into 500 ml of n-hexane, and the solid precipitate was obtained by filtration and dried under reduced pressure to obtain intermediate II;

[0052] (3) 2.36 g of intermediate II, 0.15 g of 4-dimethylaminopyridine and 1.79 g of di-tert-butyl dicarbonate were dispersed in 25.69 g of acetone, and the reaction was carried out at 25°C for 6 h;

[0053] (4) The reaction solution was added dropwise into 200 ml of n-hexane, and the solid precipitate was obtained by filtration, then the solid precipitate was dissolved in 20 ml of acetone;

[0054] (5) The operation of step (4) was repeated twice, then the reaction solution was added dropwise into 200 ml of n-hexane, and the solid precipitate was obtained by filtration and dried under reduced pressure to obtain intermediate III;

[0055] (6) 2.48 g of intermediate III and 0.65 g of triphenylsulfonium bromide were dispersed in 37.60 g of dichloromethane and 15.20 g of water, and the reaction was carried out at 25°C for 6 h;

[0056] (7) After the reaction was completed, the solution was allowed to stand until the organic phase was separated, and the reaction solution was washed with 25 ml of water for 3 times;

[0057] (8) The reaction solution was added dropwise into 200 ml of n-hexane, and the solid precipitate was obtained by filtration, then the solid precipitate was dissolved in 20 ml of dichloromethane;

[0058] (9) Repeat the operation of step (8) 2 times, then drop the reaction solution into 200 ml of n-hexane, filter and dry under reduced pressure to obtain the PAG bond type photosensitive photoresist resin.

[0059] Example 2

[0060] The specific steps for preparing the PAG bond type photosensitive photoresist resin in this example are as follows:

[0061] (1) Disperse 8.33 g of p-acetyloxy styrene, 3.20 g of p-styrene sulfonimide trifluoromethyl potassium salt and 0.38 g of RAFT chain transfer agent 2-(((dodecane sulfanyl)thioacyl)-sulfanyl) propanoic acid in 14.10 g of solvent N,N-dimethylformamide, protect with nitrogen, heat to 70°C, add 0.09 g of initiator azobisisobutyronitrile dispersed in 3.90 g of N,N-dimethylformamide, and react at 70°C for 8 h; after the reaction is completed, drop the reaction solution into 500 ml of water, filter to obtain solid precipitate, dissolve the solid precipitate in 50 ml of tetrahydrofuran, then drop into 500 ml of n-hexane, filter and dry under reduced pressure to obtain intermediate I; in this step, the addition ratio of each main material satisfies: the molar ratio of p-acetyloxy styrene and p-styrene sulfonimide trifluoromethyl potassium salt is (5.67:1), the molar ratio of p-acetyloxy styrene and RAFT chain transfer agent is (48:1), and the molar ratio of p-acetyloxy styrene and initiator is (96:1).

[0062] (2) Disperse 9.23 g of intermediate I and 3.46 g of sodium hydroxide in 36.2 g of tetrahydrofuran and 28.0 g of water, and react at 40°C for 6 h; after the reaction is completed, add hydrochloric acid to adjust the PH of the reaction solution to 7, stand still until the solution is layered, then drop the organic phase of the reaction solution into 500 ml of n-hexane, filter and dry under reduced pressure to obtain intermediate II;

[0063] (3) Disperse 2.74 g of intermediate II, 0.19 g of 4-dimethylaminopyridine and 2.23 g of di-tert-butyl dicarbonate in 30.10 g of acetone, and react at 25°C for 6 h;

[0064] (4) Drop the reaction solution into 200 ml of n-hexane, filter to obtain solid precipitate, then dissolve the solid precipitate in 20 ml of acetone;

[0065] (5) Repeat the operation of step (4) 2 times, then drop the reaction solution into 200 ml of n-hexane, filter and dry under reduced pressure to obtain intermediate III;

[0066] (6) Disperse 2.88 g of intermediate III and 0.69 g of triphenylsulfonium bromide in 20.10 g of dichloromethane and 7.10 g of water, and react at 25°C for 6 h;

[0067] (7) After the reaction is completed, stand and wait for the solution to separate into layers, and wash the organic phase of the reaction solution with 25 ml of water three times;

[0068] (8) Add the organic phase of the reaction solution dropwise into 200 ml of n-hexane, filter to obtain a solid precipitate, and then dissolve the solid precipitate into 20 ml of dichloromethane;

[0069] (9) Repeat the operation of step (8) two times, and then add the reaction solution dropwise into 200 ml of n-hexane, filter, and dry under reduced pressure to obtain the PAG bond type photosensitive photoresist resin.

[0070] Example 3

[0071] The specific steps for preparing the PAG bond type photosensitive photoresist resin in this example are as follows:

[0072] (1) Disperse 9.46 g of p-acetyloxy styrene, 2.02 g of p-styrene sulfonimide trifluoromethyl potassium salt, and 0.43 g of a RAFT chain transfer agent 2-(((dodecane sulfanyl)thioacyl)-sulfanyl) propanoic acid in 12.80 g of a solvent N,N-dimethylformamide, protect with nitrogen, heat to 70 °C, add 0.10 g of an initiator azobisisobutyronitrile dispersed in 5.20 g of N,N-dimethylformamide, and react at 70 °C for 8 h; after the reaction is completed, add the reaction solution dropwise into 500 ml of water, filter to obtain a solid precipitate, dissolve the solid precipitate into 50 ml of tetrahydrofuran, then add dropwise into 500 ml of n-hexane, filter, and dry under reduced pressure to obtain the intermediate I; in this step, the addition ratio of each main material satisfies: the molar ratio of p-acetyloxy styrene and p-styrene sulfonimide trifluoromethyl potassium salt is (120:11.77), the molar ratio of p-acetyloxy styrene and the RAFT chain transfer agent is (120:2.5), and the molar ratio of p-acetyloxy styrene and the initiator is (120:1.25).

[0073] (2) Disperse 5.90 g of the intermediate I and 2.58 g of sodium hydroxide in 28.4 g of tetrahydrofuran and 20.9 g of water, and react at 40 °C for 6 h; after the reaction is completed, add hydrochloric acid to adjust the PH of the reaction solution to 7, stand and wait for the solution to separate into layers, then add the organic phase of the reaction solution dropwise into 500 ml of n-hexane, filter, and dry under reduced pressure to obtain the intermediate II;

[0074] (3) Disperse 3.08 g of the intermediate II, 0.25 g of 4-dimethylaminopyridine, and 2.89 g of di-tert-butyl dicarbonate in 21.80 g of acetone, and react at 25 °C for 6 h;

[0075] (4) Add the reaction solution dropwise into 200 ml of n-hexane, filter to obtain a solid precipitate, and then dissolve the solid precipitate into 20 ml of acetone;

[0076] (5) Repeat the operation of step (4) twice, then drop the reaction solution into 200 ml of n-hexane, filter and dry under reduced pressure to obtain the intermediate III;

[0077] (6) Disperse 3.78 g of the intermediate III and 0.60 g of triphenylsulfonium bromide in 46.00 g of dichloromethane and 18.90 g of water, and react at 25°C for 6 h;

[0078] (7) After the reaction is completed, stand still until the solution is layered, then wash the organic phase of the reaction solution with 25 ml of water for 3 times;

[0079] (8) Drop the organic phase of the reaction solution into 200 ml of n-hexane, filter to obtain a solid precipitate, then dissolve the solid precipitate in 20 ml of dichloromethane;

[0080] (9) Repeat the operation of step (8) twice, then drop the reaction solution into 200 ml of n-hexane, filter and dry under reduced pressure to obtain the PAG-linked photosensitive photoresist resin.

[0081] Example 4

[0082] The specific steps for preparing the PAG-linked photosensitive photoresist resin in this example are as follows:

[0083] (1) Disperse 8.75 g of p-acetoxystyrene, 2.76 g of p-styrene sulfonimide trifluoromethyl potassium salt and 0.39 g of the RAFT chain transfer agent 2-(((dodecylsulfanyl)thioacetyl)-sulfanyl)propanoic acid in 14.00 g of the solvent N,N-dimethylformamide, protect with nitrogen, heat to 70°C, add 0.09 g of the initiator azobisisobutyronitrile dispersed in 4.00 g of N,N-dimethylformamide, and react at 70°C for 8 h; after the reaction is completed, drop the reaction solution into 500 ml of water, filter to obtain a solid precipitate, then dissolve the solid precipitate in 50 ml of tetrahydrofuran, drop into 500 ml of n-hexane, filter and dry under reduced pressure to obtain the intermediate I; in this step, the addition proportions of the main materials satisfy: the molar ratio of p-acetoxystyrene and p-styrene sulfonimide trifluoromethyl potassium salt is (120:17.39), the molar ratio of p-acetoxystyrene and the RAFT chain transfer agent is (120:2.5), and the molar ratio of p-acetoxystyrene and the initiator is (120:1.25).

[0084] (2) Disperse 5.61 g of the intermediate I and 2.24 g of sodium hydroxide in 28.1 g of tetrahydrofuran and 21.1 g of water, and react at 40°C for 6 h; after the reaction is completed, add hydrochloric acid to adjust the PH of the reaction solution to 7, stand still until the solution is layered, then drop the organic phase of the reaction solution into 500 ml of n-hexane, filter and dry under reduced pressure to obtain the intermediate II;

[0085] (3) 2.47 g of intermediate II, 0.18 g of 4-dimethylaminopyridine and 2.08 g of di-tert-butyl dicarbonate were dispersed in 17.30 g of acetone, and reacted at 25°C for 6 h;

[0086] (4) The reaction solution was added dropwise into 200 ml of n-hexane, and a solid precipitate was obtained by filtration. The solid precipitate was dissolved in 20 ml of acetone;

[0087] (5) The operation of step (4) was repeated twice, and then the reaction solution was added dropwise into 200 ml of n-hexane, and filtered and dried under reduced pressure to obtain intermediate III;

[0088] (6) 2.31 g of intermediate III, 0.54 g of triphenylsulfonium bromide were dispersed in 43.80 g of dichloromethane and 27.70 g of water, and reacted at 25°C for 6 h;

[0089] (7) After the reaction was completed, the solution was allowed to stand until the layers were separated, and the organic phase of the reaction solution was washed with 25 ml of water three times;

[0090] (8) The organic phase of the reaction solution was added dropwise into 200 ml of n-hexane, and a solid precipitate was obtained by filtration. The solid precipitate was dissolved in 20 ml of dichloromethane;

[0091] (9) The operation of step (8) was repeated twice, and then the reaction solution was added dropwise into 200 ml of n-hexane, and filtered and dried under reduced pressure to obtain a PAG-bonded photosensitive photoresist resin.

[0092] The PAG-bonded photosensitive photoresist resin prepared in each of the above examples was used to prepare a photoresist: the PAG-bonded photosensitive photoresist resin and a solvent were stirred and mixed to form a photoresist. In the inventor's test of the photoresist, it was found that when the mass fraction of the resin was 5% to 30%, the photoresist obtained had equivalent photoetching performance, and had characteristics such as clear photoetching morphology and few defects. Only some application examples of the present application are listed below for illustration.

[0093] Application Example 1

[0094] In this application, the PAG-bonded photosensitive photoresist resin prepared in Example 1 was used to prepare a photoresist, and the preparation steps were as follows: 100 parts by weight of the PAG-bonded photoresist resin, 600 parts by weight of propylene glycol monomethyl ether acetate and 300 parts by weight of ethyl lactate were uniformly mixed, and a 0.22 μm filter was used for filtration to prepare the photoresist of this application example.

[0095] Application Example 2

[0096] The difference from Application Example 1 is that the PAG-bonded photosensitive photoresist resin prepared in Example 2 was used to prepare a photoresist. Other aspects are the same as those of Application Example 1.

[0097] Application Example 3

[0098] Example 4 was used instead of Example 1. Other than that, the same as in Application Example 1.

[0099] Application Example 4

[0100] Example 4 was used instead of Example 1. Other than that, the same as in Application Example 1.

[0101] Performance test and evaluation

[0102] The PAG-bound photosensitive dry film resist resins prepared in the above examples were structurally characterized by infrared spectroscopy and nuclear magnetic hydrogen spectroscopy. In addition, the following tests were performed on the dry film resists of the application examples. The tests included dry film resist sensitivity test, dry film resist acid diffusion length test, and photolithography test. Details are as follows.

[0103] 1) Infrared spectroscopy and nuclear magnetic hydrogen spectroscopy characterization of PAG-bound photosensitive dry film resist resins

[0104] 2) Dry film resist sensitivity test

[0105] The dry film resists of the application examples were spin-coated on silicon wafers to form dry film resist films with a thickness of 200 nm. After pre-baking at 100°C for 60 s, exposure was performed using 254 nm ultraviolet light, and then post-exposure baking was performed at 100°C for 60 s. Then, development was performed using 2.38 wt% aqueous tetramethylammonium hydroxide solution at 23°C for 10 s. The change in thickness of the dry film resist film was measured.

[0106] 3) Dry film resist acid diffusion length test

[0107] First, the base polymer resin solution was spin-coated on a silicon wafer as a first layer film, and its thickness was measured. After pre-baking at 100°C for 60 s, the dry film resist prepared in the application examples was spin-coated on the first layer film. After pre-baking at 100°C for 60 s, exposure was performed using 254 nm ultraviolet light, and then post-exposure baking was performed at 100°C for 60 s. Then, development was performed using 2.38 wt% aqueous tetramethylammonium hydroxide solution at 23°C for 10 s. The thickness of the film on the silicon wafer after development was measured, and the acid diffusion length was the difference in thickness between the first layer film and the film after development.

[0108] The base polymer resin solution used to prepare the first layer film was prepared as follows:

[0109] (a) Base polymer resin preparation:

[0110] (1) About 22.74 g of p-acetoxystyrene and about 1.02 g of 2-(((dodecylsulfanyl)thioacyl)-sulfanyl)propanoic acid were added to a nitrogen-filled flask, then 31 g of dioxane was added to the flask, and the flask was stirred and heated to 70°C, then a mixture of dioxane (5 g) and azobisisobutyronitrile (0.24 g) was slowly injected into the flask. The reaction was carried out at 70°C for 8 hours, and then stopped;

[0111] (2) The reaction solution was then added dropwise to a beaker containing n-hexane (500 ml) while stirring, and a precipitate was produced. The dropwise addition was completed in 30 minutes. After 1 hour, the stirring was stopped, and the solid precipitate was filtered, and the solid precipitate was placed in a vacuum drying oven at 100°C for 24 hours to obtain polymeric p-acetoxystyrene;

[0112] (3) About 14.00 g of poly-p-acetoxystyrene and about 7.26 g of sodium hydroxide were added to a flask, then 60 ml of tetrahydrofuran and 45 ml of deionized water were added to the flask, and the flask was stirred and heated to 40°C. The reaction was carried out at 40°C for 6 hours, and then stopped, and hydrochloric acid was added dropwise to adjust the pH of the solution to 7, and the solution was allowed to separate;

[0113] (4) The organic phase of the reaction solution was then added dropwise to a beaker containing deionized water (500 ml) while stirring, and a precipitate was produced. The dropwise addition was completed in 30 minutes. After 1 hour, the stirring was stopped, and the solid precipitate was filtered, and the solid precipitate was placed in a vacuum drying oven at 65°C for 24 hours to obtain poly-p-hydroxystyrene.

[0114] (5) About 9.00 g of poly-p-hydroxystyrene and about 0.92 g of 4-dimethylaminopyridine and about 10.63 g of di-tert-butyl dicarbonate were added to a flask, then 120 ml of acetone was added to the flask, and the flask was stirred and heated to 25°C. The reaction was carried out at 25°C for 6 hours, and then stopped;

[0115] (6) The reaction solution was then added dropwise to a beaker containing n-hexane (500 ml) while stirring, and a precipitate was produced. The dropwise addition was completed in 30 minutes. After 1 hour, the stirring was stopped, and the solid precipitate was filtered, and the solid precipitate was dissolved in 50 ml of acetone;

[0116] (7) The operation of step (6) was repeated twice, and then the reaction solution was added dropwise to a beaker containing n-hexane (500 ml) while stirring, and a precipitate was produced. The dropwise addition was completed in 30 minutes. After 1 hour, the stirring was stopped, and the solid precipitate was filtered, and the solid precipitate was placed in a vacuum drying oven at 65°C for 24 hours to obtain a base polymer resin. The base polymer resin finally prepared has the following structural formula:

[0117]

[0118] (b) Preparation of basic polymer resin solution: Dissolve 100 parts by weight of the basic polymer resin prepared above in 600 parts by weight of propylene glycol monomethyl ether acetate and 300 parts by weight of ethyl lactate, mix evenly, and filter using a 0.22 μm filter to obtain the basic polymer resin solution.

[0119] 4) Photoresist photolithography test

[0120] Photoresists for various applications were spin-coated onto a silicon wafer to prepare a 200 nm thick photoresist film. After pre-baking at 100 °C for 60 s, the film was exposed to 254 nm ultraviolet light through a mask, followed by another 60 s exposure at 100 °C and baking. Then, development was performed at 23 °C for 10 s using a 2.38 wt% tetramethylammonium hydroxide aqueous solution. The pattern shape was observed.

[0121] The specific test and evaluation results of the synthesis of PAG bonding photoresist resin and the corresponding photoresist effect test results are as follows.

[0122] (1) As Figure 1 The image shown is the infrared spectrum of the PAG-bonded photosensitive photoresist resin in Example 1. (3450 cm⁻¹) -1 The broad absorption peak nearby is the -OH stretching vibration peak; 1760 cm⁻¹ -1 The absorption peak at 1150 cm⁻¹ corresponds to the C=O stretching vibration peak; -1 The absorption peak at 1370 cm⁻¹ is the -COC- stretching vibration peak; -1 The nearby absorption peak is the bending vibration peak of the methyl group in the tert-butyl group; 1325 cm⁻¹ -1 The absorption peak at 1660-1700 cm⁻¹ is the stretching vibration peak of S=O; -1 The absence of obvious C=C double bond absorption peaks within the range confirms the successful synthesis of PAG-bonded photosensitive photoresist resin with no residual monomers.

[0123] (2) Figure 2 The image shows the 1H NMR spectrum of the PAG-bonded photosensitive photoresist resin in Example 1. The signal peak at δ = 9.00 ppm is the hydrogen in the hydroxyl group, the signal peak at δ = 7.69-7.91 ppm is the hydrogen in the triphenylsulfide ion, the signal peak at δ = 6.00-7.40 ppm is the hydrogen on the benzene ring of the polymer side chain, the signal peak at δ = 1.4-1.5 ppm is the hydrogen in the tert-butyl group, and the remaining peaks mainly come from the hydrogen in the polymer backbone.

[0124] (3) Figures 3-4 The figures shown are the photoresist sensitivity curve and acid diffusion length curve in Application Example 1, respectively. Figure 3 As can be seen, the photoresist prepared by PAG bonding type photoresist resin has high sensitivity.Figure 4 The acid diffusion length curve of the photoresist shows that the acid diffusion length is small. By binding the anionic part of the photoacid to the polymer, the free volume of PAG can be reduced, effectively reducing the migration rate of photoacid and limiting the diffusion range of proton acid. This effectively controls the acid diffusion length, which is beneficial for reducing line edge roughness (LER) and improving resolution.

[0125] (4) Figure 5 This is an optical microscope image showing the morphology of the photolithographic pattern created using the photoresist in Example 1. Figure 6 The images show the atomic force microscopy (AFM) patterns of the photoresist prepared from the PAG-bonded photosensitive photoresist resin in Example 1 of this invention. As can be seen from the two images, the line patterns formed after photolithography exhibit clear line morphology, few defects, and excellent photolithography effect. This further confirms that PAG bonding to the resin polymer chain effectively reduces the migration rate of photoacids, limits the diffusion range of protic acids, and thus effectively controls the acid diffusion length, which is beneficial for reducing line edge roughness and improving resolution.

[0126] The above embodiments are intended to illustrate the essential content of the present invention, but are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of protection of the present invention.

Claims

1. A PAG-linkage type photosensitive photoresist resin characterized by comprising: The structure of the PAG key type photosensitive photoresist resin is as follows: Wherein, X:Y:Z=(1-70):(20-80):(1-30).

2. The method for preparing a PAG-bonded photosensitive photoresist resin according to claim 1, characterized in that, The synthetic route of the preparation method is as follows: Wherein, n=X+Y; n:Z=(2~99):1, X:Y=(0.01-3.5):

1.

3. The method for preparing a PAG-bonded photosensitive photoresist resin according to claim 2, characterized in that, The method comprises the following steps: (1) dispersing p-acetoxystyrene, potassium p-styrenesulfonate (trifluoromethylsulfonyl) imide and a RAFT chain transfer agent in a first solvent, adding an initiator to carry out a RAFT polymerization reaction, after the reaction is completed, dropping the reaction solution into a second solvent, filtering to obtain a solid precipitate, then dispersing the solid precipitate in the first solvent, dropping into a third solvent, and filtering and drying to obtain an intermediate I; (2) dispersing the intermediate I and a first base in a first solvent and a second solvent respectively to carry out a hydrolysis reaction, after the reaction is completed, adding an acid to adjust the PH of the reaction solution, standing until the solution is layered, then dropping the organic phase of the reaction solution into a second solvent, and filtering and drying to obtain an intermediate II; (3) dispersing the intermediate II, a second base and di-tert-butyl dicarbonate in a first solvent to carry out a protection group introduction reaction; (4) dropping the reaction solution into a third solvent, filtering to obtain a solid precipitate, and then dispersing the solid precipitate in a first solvent; (5) repeating the operation of step (4) multiple times, then dropping the reaction solution into a third solvent, and filtering and drying to obtain an intermediate III; (6) dispersing the intermediate III and triphenylsulfonium bromide in a first solvent and a second solvent respectively to carry out an ion exchange reaction; (7) after the reaction is completed, standing until the solution is layered, washing the organic phase of the reaction solution with a second solvent multiple times; (8) dropping the organic phase of the reaction solution into a third solvent, filtering to obtain a solid precipitate, and then dispersing the solid precipitate in a first solvent; (9) repeating the operation of step (8) multiple times, then dropping the reaction solution into a third solvent, and filtering and drying to obtain a PAG key type photosensitive photoresist resin; Wherein, the first solvent is one or more of dichloromethane, trichloromethane, dioxane, tetrahydrofuran, N,N-dimethylformamide, propylene glycol methyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, ethyl acetate, ethylene glycol monomethyl ether acetate, acetone, cyclohexanone or methanol, the second solvent is water, and the third solvent is any one of n-hexane, petroleum ether or cyclohexane.

4. The method for preparing the PAG-bonded photosensitive photoresist resin according to claim 3, characterized in that: In step (1), the molar ratio of p-acetoxystyrene to potassium p-styrenesulfonate (trifluoromethylsulfonyl) imide is (2-99):1, the molar ratio of p-acetoxystyrene to the RAFT chain transfer agent is (30-100):1, and the molar ratio of p-acetoxystyrene to the initiator is (30-300):

1.

5. The method for preparing the PAG-bonded photosensitive photoresist resin according to claim 3, characterized in that: In step (1), the initiator is an azo free radical initiator or a peroxide free radical initiator, wherein the azo free radical initiator is any one of azobisisobutyronitrile, azobisisoheptyl nitrile or dimethyl azobis isobutyrate, and the peroxide free radical initiator is any one of dibenzoyl peroxide or tert-butyl hydroperoxide.

6. The method for preparing the PAG-bonded photosensitive photoresist resin according to claim 3, characterized in that: The first base is any one of sodium hydroxide, lithium hydroxide, potassium hydroxide or ammonia water, and the second base is any one of 4-dimethylaminopyridine, lithium carbonate, sodium carbonate, potassium carbonate, potassium tert-butoxide or sodium methoxide; the acid used for adjusting the PH of the reaction solution in step (2) is any one of hydrochloric acid, phosphoric acid, formic acid or acetic acid.

7. The method for preparing the PAG-bonded photosensitive photoresist resin according to claim 3, characterized in that: The RAFT polymerization reaction temperature in step (1) is 40-100℃, and the time is 5-24h; the hydrolysis reaction temperature in step (2) is 20-70℃, and the time is 2-24h; the reaction temperature for introducing the protecting group in step (3) is 20-60℃, and the time is 2-24h; the ion exchange reaction temperature in step (6) is 20-60℃, and the time is 2-24h.

8. A photoresist, characterized by, The photoresist is formed by stirring and mixing the PAG bond type photosensitive photoresist resin of claim 1 and a solvent, wherein the mass fraction of the resin in the photoresist is 5%-30%; and the solvent is any one or more selected from propylene glycol methyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, ethyl acetate, ethylene glycol monomethyl ether acetate, tetrahydrofuran, acetone, cyclohexanone, N,N-dimethylformamide or methanol.

9. A method of forming a lithographic pattern, characterized by, The photoresist of claim 8 is used to coat a substrate to be photoetched, pre-baked, covered with a mask, exposed, post-baked, developed and obtained the photoetching pattern. The first base is any one of sodium hydroxide, lithium hydroxide, potassium hydroxide or ammonia water, and the second base is any one of 4-dimethylaminopyridine, lithium carbonate, sodium carbonate, potassium carbonate, potassium tert-butoxide or sodium methoxide; the acid used for adjusting the PH of the reaction solution in step (2) is any one of hydrochloric acid, phosphoric acid, formic acid or acetic acid.

Images