3,4-Dihydroxystyrene polymers, their preparation and photoresist compositions

Abstract

The present invention relates to the technical field of photoresist, and particularly to 3,4-dihydroxystyrene polymers, their preparation, and photoresist compositions. The raw materials of the above-mentioned 3,4-dihydroxystyrene polymers include: 3,4-diacetoxystyrene, styrene monomer, tert-butyl acrylate, and initiator; the mass ratio of 3,4-diacetoxystyrene, styrene monomer, tert-butyl acrylate, and initiator is 80-100:5-20:10-20:5-10. The preparation method of the above-mentioned 3,4-dihydroxystyrene polymer is to dissolve 3,4-diacetoxystyrene, styrene monomer, tert-butyl acrylate, and initiator in a polar organic solvent to obtain a mixed solution; preheat the polar organic solvent to 50-80 °C, drop the mixed solution into the preheated organic solvent, and carry out a constant temperature reflux reaction at 50-80 °C for 2-30 h to obtain an emulsion; decant the emulsion, then hydrolyze, filter, wash, and dry.

Description

Technical Field

[0001] The present invention relates to the technical field of photoresists, and particularly to 3,4-dihydroxystyrene polymers, their preparation, and photoresist compositions. Background Art

[0002] Lithography technology is an important means for fabricating micro-nano dimensions in the semiconductor industry. Among them, photoresist, as the core basic material of the lithography process, is the basis for pattern transfer.

[0003] Photoresist, also known as photoresist, refers to a corrosion-resistant thin film material whose solubility changes through irradiation or radiation by ultraviolet light, electron beam, ion beam, X-ray, etc. Photoresist is currently a key material for manufacturing advanced integrated circuits. Currently, it is widely used in microelectronics manufacturing fields such as discrete devices, LEDs, integrated circuits, TFT-LCDs, etc., profoundly affecting major fields such as information engineering, energy environmental protection, and national defense, and playing a very important role in the development of high-tech industries and the national economy.

[0004] Photoresist usually consists of a film-forming material, a photosensitizer, a solvent, and other additives. Through processes such as exposure, development, etching, and stripping, the pattern on the mask plate is transferred to a substrate such as a silicon wafer. Among them, the film-forming material is various photoresist resins. In the actual polymerization process, many factors will affect the molecular weight of the photoresist resin polymer. Generally, the main factors affecting the polymer molecular weight are: polymerization reaction temperature, monomer / catalyst ratio, co-catalyst dosage, molecular weight regulator, etc. For the adjustment of the molecular weight of the resin polymer, the molecular weight of the polymer is usually adjusted by changing the dosage of the initiator or chain transfer agent. With the increase of the initiator or chain transfer agent, although the control of the molecular weight is achieved, more impurities are introduced, which will not only affect the purity of the resin, thus contaminating the photoresist and causing material defects. At the same time, due to the serious acid diffusion problem of traditional photoresist after exposure, the edge roughness is large and the resolution is low.

[0005] Therefore, how to obtain a simple and effective method for controlling the molecular weight of the polymer without introducing other impurities, and improve the resolution of the photoresist and enhance the etching resistance performance has become a technical problem to be solved urgently at present. Summary of the Invention

[0006] The purpose of the present invention is to solve the disadvantages existing in the prior art, and to propose a 3,4-dihydroxystyrene polymer and its preparation method, and a photoresist composition and its preparation method.

[0007] A 3,4-dihydroxystyrene polymer, the raw materials of which include: 3,4-diacetoxystyrene, styrene monomer, tert-butyl acrylate, and initiator; the mass ratio of 3,4-diacetoxystyrene, styrene monomer, tert-butyl acrylate, and initiator is 80-100:5-20:10-20:5-10.

[0008] Its structural formula is as follows:

[0009] .

[0010] Preferably, the initiator is azobisisoheptonitrile or / and dimethyl 2,2'-azobis(2-methylpropionate).

[0011] The preparation method of the above 3,4-dihydroxystyrene polymer includes the following steps:

[0012] (1) Mix 3,4-diacetoxystyrene, styrene monomer, and tert-butyl acrylate evenly to obtain a monomer solution;

[0013] (2) Preheat the polar organic solvent to 50-80 °C, and simultaneously add the monomer solution and initiator obtained in step (1) to the preheated organic solvent, and carry out a constant-temperature reflux reaction at 50-80 °C for 2-30 h to obtain an emulsion;

[0014] (3) Purify the emulsion obtained in step (2), then hydrolyze, filter, wash, and dry.

[0015] Preferably, the specific operation of purification is as follows: Add the emulsion obtained in step (2) to a polar organic solvent at 30-80 °C, continue to stir for 1-10 h after complete dissolution, then cool down to 5-15 °C, and decant the upper layer solution; then add it to a non-polar organic solvent at 30-80 °C, continue to stir for 1-10 h after complete dissolution, then cool down to 5-15 °C, and decant the upper layer solution; then add it to a polar organic solvent at 30-80 °C, continue to stir for 1-10 h after complete dissolution, then cool down to 5-15 °C, and decant the upper layer solution.

[0016] Preferably, the specific operation of hydrolysis is as follows: Add the purified product to a polar organic solvent at 30-80 °C, stir after complete dissolution, and add ammonia water with a mass fraction of 20-28% during the stirring process, and react at 30-50 °C for 10-24 h.

[0017] Preferably, the specific operation of washing is as follows: Add the filtrate obtained by filtration to ethyl acetate, heat up to 20-30 °C, add deionized water after complete dissolution, heat up to 45-55 °C, stir and then layer, and discard the lower aqueous phase.

[0018] A photoresist composition, the raw materials of which include, by mass percentage: 10-30% of the above-mentioned 3,4-dihydroxystyrene polymer, 2-5% of nano titanium dioxide, 0.5-1% of carboxyl-terminated polyamidoamine, 1-2% of polyvinylpyrrolidone, 1-3% of 3-hydroxy-1-adamantyl methacrylate, 0.2-1% of photoacid generator, 0.01-0.2% of basic additive, 0.01-0.15% of leveling agent, and the balance is solvent.

[0019] Preferably, the photoacid generator is at least one of diphenyliodonium trifluoromethanesulfonate, diphenyliodonium camphorsulfonate, diphenyliodonium perfluoro-1-butanesulfonate, diphenyliodonium perfluorooctanesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium camphorsulfonate, triphenylsulfonium perfluoro-1-butanesulfonate, triphenylsulfonium perfluorooctanesulfonate.

[0020] Preferably, the basic additive is at least one of tetrabutylammonium hydroxide, tetrabutylammonium acetate, tri-n-octylamine, 2,6-diisopropylamine, diethanolamine.

[0021] Preferably, the solvent is at least one of propylene glycol monomethyl ether acetate, ethyl lactate, 2-heptanone, ethylene glycol monomethyl ether acetate, cyclohexanone.

[0022] The preparation method of the above-mentioned photoresist composition includes the following steps:

[0023] S1. Add nano titanium dioxide, carboxyl-terminated polyamidoamine, and polyvinylpyrrolidone into water, ultrasonically treat for 1-2 h, perform hydrothermal reaction at 200-230 °C for 2-6 h, the reaction pressure is 0.8-1 MPa, cool to room temperature, centrifuge, wash, vacuum dry, and pulverize to obtain grafted titanium dioxide;

[0024] S2. Add the grafted titanium dioxide into water and stir evenly, add the photoacid generator thereto and ultrasonically treat for 1-2 h, spray dry, add the above-mentioned 3,4-dihydroxystyrene polymer, 3-hydroxy-1-adamantyl methacrylate, basic additive, and leveling agent and mix evenly, then add the solvent and mix evenly.

[0025] The using method of the above-mentioned photoresist composition is characterized by including the following steps: Spin-coat the above-mentioned photoresist composition on a silicon wafer, and sequentially go through pre-baking, exposure, post-baking, and development to obtain a photolithography pattern; wherein, the pre-baking temperature is 70-120 °C, the exposure energy is 5-70 mJ / cm 2 , the post-baking temperature is 90-150 °C; the development time is 30-130 s.

[0026] Preferably, a tetramethylammonium hydroxide solution is used as the developer, and the mass fraction of the tetramethylammonium hydroxide solution is 2.38%.

[0027] Beneficial effects: The objective of the present invention is to provide a film-forming substance, which can conveniently and effectively control the molecular weight of the polymer without introducing other impurities. By selecting a solvent, the present invention can effectively promote the polymerization reaction, effectively control the molecular weight range of the resin, strictly control the introduction of metal ions during the reaction process, and use electronic-grade materials throughout, enabling the product to achieve a metal ion level below 10 ppb and the total metal ion content to reach below 50 ppb. At the same time, the polymerization conditions of the present invention are mild, the controllability of the polymer molecular weight and its distribution is strong, the performance of the polymer product is excellent, and the application performance of the product is good. After the feasibility reaction test in the laboratory, it is introduced into industrial production on this basis.

[0028] The present invention uses nano-titanium dioxide in combination with carboxyl-terminated polyamidoamine. Under the coordination of polyvinylpyrrolidone, a hydrothermal reaction is carried out to promote the grafting of the dendritic polyamidoamine structure on the surface of titanium dioxide. This not only causes steric hindrance to the nano-titanium dioxide particles, effectively overcomes the agglomeration phenomenon, and ensures the original light absorption performance of the nano-titanium dioxide, but also after grafting, the titanium dioxide is compounded with a photoacid generator and loaded with the photoacid generator, and the absorbed light energy can be quickly transferred to the photosensitizer, enabling the photoresist to have the characteristic of small line edge roughness during the lithography process and effectively improving the resolution.

[0029] Compared with the single nano-titanium dioxide material, the grafted nano-titanium dioxide obtained in the present invention is beneficial to reducing the surface tension of the photoresist, enhancing the infiltration of the substrate, and compounding with 3,4-dihydroxystyrene polymers and 3-hydroxy-1-adamantyl methacrylate, which can improve the adhesion between the photoresist film and the substrate, reduce the penetration of acid molecules, and at the same time, the photoresist film has high density, improving the resolution of the photoresist. Description of the Drawings

[0030] Figure 1 It is a physical photo of the 3,4-dihydroxystyrene polymer obtained in Example 4.

[0031] Figure 2 It is a solution photo of the 3,4-dihydroxystyrene polymer obtained in Example 4 dissolved in propylene glycol methyl ether acetate.

[0032] Figure 3 It is a comparison chart of the number average molecular weight (M w ) and the polymer dispersity index (PDI) of the 3,4-dihydroxystyrene polymers obtained in Examples 1-4.

[0033] Figure 4 It is a gel permeation chromatogram of the 3,4-dihydroxystyrene polymer obtained in Example 4.

[0034] Figure 5 It is an infrared spectrum diagram of the 3,4-dihydroxystyrene polymer obtained in Example 4.

[0035] Figure 6 It is the ultraviolet spectrum diagram of the 3,4-dihydroxystyrene polymer obtained in Example 4.

[0036] Figure 7 It is the comparison chart of resolution and sensitivity after lithography of the photoresist compositions obtained in Example 7 and Comparative Examples 1-3. Detailed implementation manners

[0037] The present invention will be further illustrated below in conjunction with specific embodiments.

[0038] All raw materials used below are electronic-grade products.

[0039] Example 1

[0040] 1.1 Polymerization reaction

[0041] Add 40 mL of methanol to a 1000 mL three-necked flask, stir mechanically, control the reaction temperature at 68 °C, and set the rotation speed at 350 rpm. In dropping funnel 1, add 90 g of 3,4-diacetoxystyrene, 25 g of styrene, and 18 g of tert-butyl acrylate and mix evenly; in dropping funnel 2, add an azobisisobutyronitrile solution (8 g of azobisisobutyronitrile dissolved in 220 mL of methanol); control the dropping time for both to be 6.5 h. After the dropping is completed, a blue-light-emitting emulsion appears.

[0042] After the dropping is completed, keep the temperature and continue to hold the polymerization for 8 h. The product in the flask is a viscous white emulsion.

[0043] 1.2 Purification

[0044] After the above polymerization reaction is completed, add 250 mL of methanol to the flask, heat up to 58 °C, dissolve the crude product, stir at 350 rpm for 1.5 h, stop stirring, cool down to 12 °C, and decant the upper-layer methanol solution; repeat the above methanol decantation step 2 times.

[0045] Add 220 mL of n-heptane to the flask, heat up to 58 °C, dissolve the crude product, stir at 350 rpm for 1.5 h, stop stirring, cool down to 12 °C, and decant the upper-layer n-heptane solution; repeat the above n-heptane decantation step 1 time.

[0046] Add 250 mL of methanol to the flask, heat up to 58 °C, dissolve the crude product, stir at 350 rpm for 1.5 h, stop stirring, cool down to 12 °C, and decant the upper-layer methanol solution.

[0047] 1.3 Hydrolysis

[0048] After the above decantation, 250 mL of methanol was added to the flask. After heating to 58 °C to dissolve the product, stirring was started, and 40 g of 28% ammonia water was added. The reaction time was controlled to be 12 h. After the reaction was completed, a brown viscous solution was formed.

[0049] 1.4 Filtration

[0050] Filter using a 0.2 μm filter membrane. The filtration rate was moderate and it took about 12 h.

[0051] 1.5 Washing

[0052] After the above filtration, 2 kg of ethyl acetate was added, the temperature was raised to 25 °C, after dissolution, 450 g of deionized water was added, heated to 55 °C, stirred for 15 min and then stopped, transferred to a separatory funnel, layered, and the lower aqueous phase was discarded. Continue to add deionized water and repeat the above steps 5 times. The total cumulative amount of deionized water used was 2.8 kg. Finally, most of the ethyl acetate in the ethyl acetate phase was removed by rotary evaporation to obtain a light brown solid.

[0053] Example 2

[0054] 2.1 Polymerization reaction

[0055] 35 mL of methanol was added to a 1000 mL three-necked flask, mechanically stirred, the reaction temperature was controlled to be 66 °C, and the set rotation speed was 280 rpm. 78 g of 3,4-diacetoxystyrene, 20 g of styrene, and 15 g of tert-butyl acrylate were mixed evenly in dropping funnel 1; 2,2'-azobis(2-methylpropionitrile) solution (6.5 g of 2,2'-azobis(2-methylpropionitrile) dissolved in 180 mL of methanol) was added to dropping funnel 2; the dropping time was controlled to be 6.2 h for both. After the dropping was completed, a blue-tinged emulsion appeared.

[0056] After the dropping was completed, the temperature was controlled and the polymerization was continued for 7.8 h while maintaining the temperature. The product in the flask was a viscous white emulsion.

[0057] 2.2 Purification

[0058] After the above polymerization reaction was completed, 220 mL of methanol was added to the flask, heated to 56 °C, after dissolving the crude product, stirred at 280 rpm for 1.2 h, after stopping stirring, cooled to 12 °C, and the upper methanol solution was decanted; the above methanol decantation step was repeated 2 times.

[0059] 190 mL of n-heptane was added to the flask, heated to 56 °C, after dissolving the crude product, stirred at 280 rpm for 1.5 h, after stopping stirring, cooled to 12 °C, and the upper n-heptane solution was decanted; the above n-heptane decantation step was repeated 1 time.

[0060] Add 220 mL of methanol to the flask, heat it up to 56 °C, dissolve the crude product, stir it at 280 rpm for 1.2 h. After stopping the stirring, cool it down to 12 °C and decant the upper layer of methanol solution.

[0061] 2.3 Hydrolysis

[0062] After the above decantation, add 210 mL of methanol to the flask, heat it up to 57 °C to dissolve the product, start stirring, and add 35 g of ammonia water with a mass fraction of 28%. Control the reaction time to be 11 h. After the reaction is completed, a brown viscous solution is formed.

[0063] 2.4 Filtration

[0064] Filter using a 0.2 μm filter membrane. The filtration rate is moderate and it takes about 14 h.

[0065] 2.5 Washing

[0066] After the above filtration, add 1.6 kg of ethyl acetate, raise the temperature to 22 °C, dissolve it, add 380 g of deionized water, heat it to 48 °C, stir for 15 min and then stop. Transfer it to a separatory funnel, let it separate into layers, and discard the lower aqueous phase. Continue to add deionized water and repeat the above steps 5 times. The total cumulative amount of deionized water used is 2.2 kg. Finally, most of the ethyl acetate in the ethyl acetate phase is removed by rotary evaporation to obtain a light brown solid.

[0067] Example 3

[0068] 3.1 Polymerization reaction

[0069] Add 40 mL of methanol to a 1000 mL three-necked flask, stir mechanically, control the reaction temperature at 65 °C, and set the rotation speed at 300 rpm. In dropping funnel 1, add 80 g of 3,4-diacetoxystyrene, 25 g of styrene, and 20 g of tert-butyl acrylate and mix them evenly; in dropping funnel 2, add an azobisisobutyronitrile solution (7.5 g of azobisisobutyronitrile dissolved in 200 mL of methanol); control the dropping time for both to be 6.5 h. After the dropping is completed, a blue-tinged emulsion appears.

[0070] After the dropping is completed, keep the temperature and continue to polymerize for 8 h while maintaining the temperature. The product in the flask is a viscous white emulsion.

[0071] 3.2 Purification

[0072] After the above polymerization reaction is completed, add 230 mL of methanol to the flask, heat it up to 55 °C, dissolve the crude product, stir it at 300 rpm for 1 h, stop stirring, cool it down to 10 °C, and decant the upper layer of methanol solution; repeat the above methanol decantation step 2 times.

[0073] Add 200 mL of n-heptane to the flask, heat it up to 55 °C, dissolve the crude product, stir it at 300 rpm for 1 h. After stopping the stirring, cool it down to 10 °C and decant the upper n-heptane solution; repeat the above n-heptane decantation step once.

[0074] Add 230 mL of methanol to the flask, heat it up to 55 °C, dissolve the crude product, stir it at 300 rpm for 1 h. After stopping the stirring, cool it down to 10 °C and decant the upper methanol solution.

[0075] 3.3 Hydrolysis

[0076] After the above decantation, add 200 mL of methanol to the flask, heat it up to 55 °C to dissolve the product, start stirring, and add 33 g of 28% ammonia water, control the reaction time to be 10 h. After the reaction is completed, a brown viscous solution is formed.

[0077] 3.4 Filtration

[0078] Filter using a 0.2 μm filter membrane. The filtration speed is moderate, taking about 10 h.

[0079] 3.5 Washing

[0080] After the above filtration, add 1.8 kg of ethyl acetate, raise the temperature to 25 °C, dissolve it, add 400 g of deionized water, heat it to 50 °C, stop stirring after 15 min, transfer it to a separatory funnel, layer it, and discard the lower aqueous phase. Continue to add deionized water and repeat the above steps 5 times. The total cumulative amount of deionized water used is 2.5 kg. Finally, most of the ethyl acetate in the ethyl acetate phase is removed by rotary evaporation to obtain a light brown solid.

[0081] Example 4

[0082] 4.1 Polymerization reaction

[0083] Add 39 mL of methanol to a 1000 mL three-necked flask, stir mechanically, control the reaction temperature to be 67 °C, and set the rotation speed to 310 rpm. Add 87 g of 3,4-diacetoxystyrene, 22.5 g of styrene, and 17.2 g of tert-butyl acrylate to dropping funnel 1 and mix evenly; add an azobisisobutyronitrile solution (7.6 g of azobisisobutyronitrile dissolved in 210 mL of methanol) to dropping funnel 2; control the dropping time for both to be 6.3 h. After the dropping is completed, a blue-emitting emulsion appears.

[0084] After the dropping is completed, keep the temperature and continue to polymerize for 7.5 h while maintaining the temperature. The product in the flask is a viscous white emulsion.

[0085] 4.2 Purification

[0086] After the above polymerization reaction was completed, 238 mL of methanol was added to the flask, and the temperature was raised to 57 °C. After dissolving the crude product, it was stirred at 310 rpm for 1 h. After stopping the stirring, the temperature was lowered to 11 °C, and the upper-layer methanol solution was decanted; the above methanol decantation step was repeated 2 times.

[0087] 205 mL of n-heptane was added to the flask, and the temperature was raised to 57 °C. After dissolving the crude product, it was stirred at 310 rpm for 1 h. After stopping the stirring, the temperature was lowered to 11 °C, and the upper-layer n-heptane solution was decanted; the above n-heptane decantation step was repeated 1 time.

[0088] 238 mL of methanol was added to the flask, and the temperature was raised to 57 °C. After dissolving the crude product, it was stirred at 310 rpm for 1 h. After stopping the stirring, the temperature was lowered to 11 °C, and the upper-layer methanol solution was decanted.

[0089] 4.3 Hydrolysis

[0090] After the above decantation, 238 mL of methanol was added to the flask. After dissolving the product by raising the temperature to 57 °C, stirring was started, and 39.5 g of 28% ammonia water was added. The reaction time was controlled for 11 h. After the reaction was completed, a brown viscous solution was formed.

[0091] 4.4 Filtration

[0092] Filtration was carried out using a 0.2 μm filter membrane. The filtration speed was slow and it took about 24 h.

[0093] 4.5 Washing

[0094] After the above filtration, 1.86 kg of ethyl acetate was added, the temperature was raised to 27 °C, and after dissolution, 430 g of deionized water was added. The temperature was raised to 54 °C, and after stirring for 11 min, it was stopped, transferred to a separatory funnel, and layered. The lower aqueous phase was discarded. Deionized water was continuously added, and the above steps were repeated 5 times. The total cumulative amount of deionized water used was 2.58 kg. Finally, most of the ethyl acetate in the ethyl acetate phase was removed by rotary evaporation to obtain a light brown solid (as Figure 1 shown). The light brown solid obtained in this example was dissolved in propylene glycol methyl ether acetate as Figure 2 shown.

[0095] Gel permeation chromatography analysis was carried out on the 3,4-dihydroxystyrene polymers obtained in Examples 1-4, and the results are as Figure 3 shown. The gel permeation chromatogram of the 3,4-dihydroxystyrene polymer obtained in Example 4 is as Figure 4 shown, and its infrared spectrum is as Figure 5 shown, and its ultraviolet spectrum is as Figure 6 shown.

[0096] From Figures 3 - 6It can be seen that the number-average molecular weight of the 3,4-dihydroxystyrene polymers obtained in Examples 1-4 is 18,000-22,000, and the polydispersity index of the polymers is 1.48-1.52, which confirms that the present invention effectively realizes the control of the polymer molecular weight range.

[0097] Example 5

[0098] A photoresist composition, the raw materials of which by mass percentage include: 10% of the 3,4-dihydroxystyrene polymer obtained in Example 4, 2% of P25 nano-titanium dioxide, 0.5% of carboxyl-terminated polyamidoamine, 1% of polyvinylpyrrolidone, 1% of 3-hydroxy-1-adamantyl methacrylate, 0.2% of triphenylsulfonium perfluoro-1-butanesulfonate, 0.01% of tri-n-octylamine, 0.01% of 3M fluorocarbon surfactant FC-4430, and the balance is propylene glycol methyl ether acetate.

[0099] The preparation method of the above photoresist composition includes the following steps:

[0100] S1. Add P25 nano-titanium dioxide, carboxyl-terminated polyamidoamine, and polyvinylpyrrolidone to water, ultrasonically treat for 1 h, the ultrasonic frequency is 5 kHz, carry out hydrothermal reaction at 200 °C for 2 h, the reaction pressure is 0.8 MPa, cool to room temperature, centrifuge, wash once with deionized water, dry in vacuum, and pulverize to obtain grafted titanium dioxide;

[0101] S2. Add the grafted titanium dioxide to deionized water and stir evenly, add triphenylsulfonium perfluoro-1-butanesulfonate thereto and ultrasonically treat for 1 h, the ultrasonic frequency is 3 kHz, spray dry, add the 3,4-dihydroxystyrene polymer obtained in Example 4, 3-hydroxy-1-adamantyl methacrylate, tri-n-octylamine, and 3M fluorocarbon surfactant FC-4430, mix evenly, add propylene glycol methyl ether acetate and mix evenly, and then filter through a 0.25 μm nylon membrane.

[0102] Example 6

[0103] A photoresist composition, the raw materials of which by mass percentage include: 30% of the 3,4-dihydroxystyrene polymer obtained in Example 4, 5% of P25 nano-titanium dioxide, 1% of carboxyl-terminated polyamidoamine, 2% of polyvinylpyrrolidone, 3% of 3-hydroxy-1-adamantyl methacrylate, 1% of triphenylsulfonium perfluoro-1-butanesulfonate, 0.2% of tri-n-octylamine, 0.15% of 3M fluorocarbon surfactant FC-4430, and the balance is propylene glycol methyl ether acetate.

[0104] The preparation method of the above photoresist composition includes the following steps:

[0105] S1. Add P25 nano-titanium dioxide, carboxyl-terminated polyamidoamine, and polyvinylpyrrolidone into water and ultrasonically treat for 2 h at an ultrasonic frequency of 15 kHz. Conduct a hydrothermal reaction at 230 °C for 6 h with a reaction pressure of 1 MPa. Cool to room temperature, centrifuge, wash 3 times with deionized water, dry in vacuum, and pulverize to obtain grafted titanium dioxide;

[0106] S2. Add the grafted titanium dioxide into deionized water and stir evenly. Add triphenylsulfonium perfluoro-1-butanesulfonate thereto and ultrasonically treat for 2 h at an ultrasonic frequency of 10 kHz. Spray dry, add the 3,4-dihydroxystyrene polymer obtained in Example 4, 3-hydroxy-1-adamantyl methacrylate, tri-n-octylamine, and 3M fluorocarbon surfactant FC-4430, mix evenly, add propylene glycol methyl ether acetate and mix evenly, and then filter through a 0.25-μm nylon membrane.

[0107] Example 7

[0108] A photoresist composition, the raw materials of which include, by mass percentage: 20% of the 3,4-dihydroxystyrene polymer obtained in Example 4, 3.5% of P25 nano-titanium dioxide, 0.8% of carboxyl-terminated polyamidoamine, 1.5% of polyvinylpyrrolidone, 2% of 3-hydroxy-1-adamantyl methacrylate, 0.6% of triphenylsulfonium perfluoro-1-butanesulfonate, 0.1% of tri-n-octylamine, 0.1% of 3M fluorocarbon surfactant FC-4430, and the balance is propylene glycol methyl ether acetate.

[0109] The preparation method of the above photoresist composition includes the following steps:

[0110] S1. Add P25 nano-titanium dioxide, carboxyl-terminated polyamidoamine, and polyvinylpyrrolidone into water and ultrasonically treat for 1.5 h at an ultrasonic frequency of 9 kHz. Conduct a hydrothermal reaction at 220 °C for 4 h with a reaction pressure of 0.9 MPa. Cool to room temperature, centrifuge, wash 2 times with deionized water, dry in vacuum, and pulverize to obtain grafted titanium dioxide;

[0111] S2. Add the grafted titanium dioxide into deionized water and stir evenly. Add triphenylsulfonium perfluoro-1-butanesulfonate thereto and ultrasonically treat for 1.5 h at an ultrasonic frequency of 6 kHz. Spray dry, add the 3,4-dihydroxystyrene polymer obtained in Example 4, 3-hydroxy-1-adamantyl methacrylate, tri-n-octylamine, and 3M fluorocarbon surfactant FC-4430, mix evenly, add propylene glycol methyl ether acetate and mix evenly, and then filter through a 0.25-μm nylon membrane.

[0112] Comparative Example 1

[0113] A photoresist composition, the raw materials of which by mass percentage include: 22% of the 3,4-dihydroxystyrene polymer obtained in Example 4, 3.5% of P25 nano-titanium dioxide, 0.8% of carboxyl-terminated polyamidoamine, 1.5% of polyvinylpyrrolidone, 0.6% of triphenylsulfonium perfluoro-1-butanesulfonate, 0.1% of tri-n-octylamine, 0.1% of 3M fluorocarbon surfactant FC-4430, and the balance is propylene glycol methyl ether acetate.

[0114] The preparation method of the above-mentioned photoresist composition includes the following steps:

[0115] S1. Add P25 nano-titanium dioxide, carboxyl-terminated polyamidoamine, and polyvinylpyrrolidone to water, ultrasonically treat for 1.5 h, the ultrasonic frequency is 9 kHz, carry out hydrothermal reaction at 220 °C for 4 h, the reaction pressure is 0.9 MPa, cool to room temperature, centrifuge, wash twice with deionized water, vacuum dry, and pulverize to obtain grafted titanium dioxide;

[0116] S2. Add the grafted titanium dioxide to deionized water and stir evenly, add triphenylsulfonium perfluoro-1-butanesulfonate thereto and ultrasonically treat for 1.5 h, the ultrasonic frequency is 6 kHz, spray dry, add the 3,4-dihydroxystyrene polymer obtained in Example 4, tri-n-octylamine, and 3M fluorocarbon surfactant FC-4430, mix evenly, add propylene glycol methyl ether acetate and mix evenly, and then filter through a 0.25 μm nylon membrane.

[0117] Comparative Example 2

[0118] A photoresist composition, the raw materials of which by mass percentage include: 20% of the 3,4-dihydroxystyrene polymer obtained in Example 4, 3.5% of P25 nano-titanium dioxide, 0.8% of carboxyl-terminated polyamidoamine, 1.5% of polyvinylpyrrolidone, 2% of 3-hydroxy-1-adamantyl methacrylate, 0.6% of triphenylsulfonium perfluoro-1-butanesulfonate, 0.1% of tri-n-octylamine, 0.1% of 3M fluorocarbon surfactant FC-4430, and the balance is propylene glycol methyl ether acetate.

[0119] The preparation method of the above-mentioned photoresist composition includes the following steps:

[0120] S1. Add P25 nano-titanium dioxide, carboxyl-terminated polyamidoamine, and polyvinylpyrrolidone to water, ultrasonically treat for 1.5 h, the ultrasonic frequency is 9 kHz, carry out hydrothermal reaction at 220 °C for 4 h, the reaction pressure is 0.9 MPa, cool to room temperature, centrifuge, wash twice with deionized water, vacuum dry, and pulverize to obtain grafted titanium dioxide;

[0121] S2. Mix grafted titanium dioxide, triphenylsulfonium perfluoro-1-butanesulfonate, the 3,4-dihydroxystyrene polymer obtained in Example 4, 3-hydroxy-1-adamantyl methacrylate, tri-n-octylamine, and 3M fluorocarbon surfactant FC-4430 evenly, add propylene glycol methyl ether acetate and mix evenly, and then filter through a 0.25 μm nylon membrane.

[0122] Comparative Example 3

[0123] A photoresist composition, the raw materials of which include, by mass percentage: 20% of the 3,4-dihydroxystyrene polymer obtained in Example 4, 3.5% of P25 nano-titanium dioxide, 0.8% of carboxyl-terminated polyamidoamine, 1.5% of polyvinylpyrrolidone, 2% of 3-hydroxy-1-adamantyl methacrylate, 0.6% of triphenylsulfonium perfluoro-1-butanesulfonate, 0.1% of tri-n-octylamine, 0.1% of 3M fluorocarbon surfactant FC-4430, and the balance is propylene glycol methyl ether acetate.

[0124] The preparation method of the above photoresist composition includes the following steps:

[0125] S1. Mix P25 nano-titanium dioxide and carboxyl-terminated polyamidoamine to obtain composite titanium dioxide;

[0126] S2. Add the composite titanium dioxide to deionized water and stir evenly, add triphenylsulfonium perfluoro-1-butanesulfonate thereto and perform ultrasonic treatment for 1.5 h, the ultrasonic frequency is 6 kHz, spray dry, add the 3,4-dihydroxystyrene polymer obtained in Example 4, 3-hydroxy-1-adamantyl methacrylate, tri-n-octylamine, and 3M fluorocarbon surfactant FC-4430 and mix evenly, add propylene glycol methyl ether acetate and mix evenly, and then filter through a 0.25 μm nylon membrane.

[0127] Perform photolithography using the photoresist compositions obtained in Example 7 and Comparative Examples 1-3 as follows: Spin-coat each photoresist composition on a silicon wafer, pre-bake at 100 °C for 90 s, then perform selective exposure using a KrF exposure machine, and then post-bake at 130 °C for 90 s. After the silicon wafer is cooled to room temperature, develop it with a 2.38% aqueous solution of tetramethylammonium hydroxide developer for 60 s, and finally rinse with deionized water for 45 s to obtain the required photolithography pattern.

[0128] Resolution evaluation: Observe using a scanning electron microscope and test its minimum resolution.

[0129] Sensitivity evaluation: Measure its photosensitivity using a scanning electron microscope. The sensitivity is the lowest exposure amount for clearly showing a pattern with a 150 nm line width (line: pitch = 1:1). The smaller the value of the exposure amount, the higher the sensitivity.

[0130] AsFigure 7 As shown, the photoresist composition obtained in Example 7 exhibited extremely high resolution and sensitivity, which were superior to those of Comparative Examples 1-3 (P < 0.05).

[0131] Meanwhile, the cross-sectional shape of the line pattern obtained at the minimum exposure amount in the above sensitivity test was observed using a scanning electron microscope. When the ratio of the top line width to the bottom line width of the line pattern ≥ 1.2, the cross-section of the line pattern was an inverted trapezoid, and the pattern quality was poor; when the ratio was within 1.1 - 1.2, the pattern quality was qualified; when the ratio < 1.1, the cross-section of the line pattern was a rectangle, and the pattern quality was good. The pattern quality of the photoresist compositions obtained in Example 7 and Comparative Examples 1-3 was good.

[0132] The applicant believes that: in the present invention, nano-titanium dioxide is combined with carboxyl-terminated polyamidoamine, and under the cooperation of polyvinylpyrrolidone, a hydrothermal reaction is carried out to promote the grafting of the dendritic polyamidoamine structure on the surface of titanium dioxide. This not only causes steric hindrance of the nano-titanium dioxide particles, effectively overcomes the agglomeration phenomenon, and ensures the original light absorption performance of the nano-titanium dioxide, but also after grafting, titanium dioxide is compounded with a photoacid generator and loaded with the photoacid generator, which can quickly transfer the absorbed light energy to the photosensitizer, making the photoresist have the characteristic of small line edge roughness during the lithography process and effectively improving the resolution. At the same time, the grafted nano-titanium dioxide obtained in the present invention is beneficial to reducing the surface tension of the photoresist, enhancing the wetting of the substrate, and when compounded with 3,4-dihydroxystyrene polymers and 3-hydroxy-1-adamantyl methacrylate, it can improve the adhesion between the photoresist film and the substrate, reduce the penetration of acid molecules, and at the same time, the photoresist film has high density, improving the resolution of the photoresist.

[0133] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A photoresist composition, characterized in that The raw materials include, by mass percentage: 10-30% of 3,4-dihydroxystyrene polymer, 2-5% of nano titanium dioxide, 0.5-1% of terminal carboxyl polyamide amine, 1-2% of polyvinyl pyrrolidone, 1-3% of 3-hydroxy-1-adamantyl methacrylate, 0.2-1% of photoacid generator, 0.01-0.2% of alkaline additive, 0.01-0.15% of leveling agent, and the balance is solvent; The photoacid generator is at least one of diphenyliodonium trifluoromethanesulfonate, diphenyliodonium camphorsulfonate, diphenyliodonium perfluoro-1-butanesulfonate, diphenyliodonium perfluorooctanesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium camphorsulfonate, triphenylsulfonium perfluoro-1-butanesulfonate, and triphenylsulfonium perfluorooctanesulfonate; The raw materials of the 3,4-dihydroxystyrene polymer include: 3,4-diacetoxystyrene, styrene monomer, tert-butyl acrylate, and initiator; The mass ratio of 3,4-diacetoxystyrene, styrene monomer, tert-butyl acrylate and initiator is 80-100:5-20:10-20:5-10; Prepared by the following steps: S1. Add nano titanium dioxide, carboxyl-terminated polyamidoamine and polyvinyl pyrrolidone to water for ultrasonic treatment for 1-2 hours, perform hydrothermal reaction at 200-230° C. for 2-6 hours, and the reaction pressure is 0.8-1 MPa. Then, the mixture is cooled to room temperature, centrifuged, washed, vacuum dried and crushed to obtain grafted titanium dioxide. S2. Add grafted titanium dioxide to water and stir evenly, add a photoacid generator thereto and ultrasonically treat for 1-2 hours, spray dry, add 3,4-dihydroxystyrene polymer, 3-hydroxy-1-adamantyl methacrylate, alkaline additive, and leveling agent and mix evenly, add a solvent and mix evenly.

2. The photoresist composition according to claim 1, characterized in that: The initiator is azobisisoheptanitrile or / and dimethyl azobisisobutyrate.

3. The photoresist composition according to claim 1, characterized in that: The 3,4-dihydroxystyrene polymer is prepared by the following steps: (1) 3,4-diacetoxystyrene, styrene monomer, and tert-butyl acrylate are uniformly mixed to obtain a monomer solution; (2) preheating the polar organic solvent to 50-80° C., adding the monomer solution and the initiator obtained in step (1) to the preheated organic solvent, and refluxing at 50-80° C. for 2-30 hours to obtain an emulsion; (3) The emulsion obtained in step (2) is purified, then hydrolyzed, filtered, washed and dried.

4. The photoresist composition according to claim 3, characterized in that: The specific operation of purification is as follows: add the emulsion obtained in step (2) to a polar organic solvent at a temperature of 30-80°C, continue stirring for 1-10 hours after complete dissolution, then cool to 5-15°C, and decant the upper solution; then add it to a non-polar organic solvent at a temperature of 30-80°C, continue stirring for 1-10 hours after complete dissolution, then cool to 5-15°C, and decant the upper solution; then add it to a polar organic solvent at a temperature of 30-80°C, continue stirring for 1-10 hours after complete dissolution, then cool to 5-15°C, and decant the upper solution.

5. The photoresist composition according to claim 3, characterized in that: The specific operation of hydrolysis is as follows: add the purified product to a polar organic solvent at a temperature of 30-80°C, stir after complete dissolution, add 20-28% ammonia water during stirring, and react at 30-50°C for 10-24h.

6. The photoresist composition according to claim 3, characterized in that: The specific operation of washing is as follows: add the filtrate obtained by filtration into ethyl acetate, heat it to 20-30°C, add deionized water after it is completely dissolved, heat it to 45-55°C, stir and separate the layers, and discard the lower aqueous phase.

7. The photoresist composition according to claim 1, characterized in that: The alkaline additive is at least one of tetrabutylammonium hydroxide, tetrabutylammonium acetate, tri-n-octylamine, 2,6-diisopropylamine and diethanolamine.

8. The photoresist composition according to claim 1, characterized in that: The solvent is at least one of propylene glycol methyl ether acetate, ethyl lactate, 2-heptanone, ethylene glycol monomethyl ether acetate and cyclohexanone.

9. A method for preparing a photoresist composition according to any one of claims 1 to 8, characterized in that: The steps include: S1. Add nano titanium dioxide, carboxyl-terminated polyamidoamine and polyvinyl pyrrolidone to water for ultrasonic treatment for 1-2 hours, perform hydrothermal reaction at 200-230° C. for 2-6 hours, and the reaction pressure is 0.8-1 MPa. Then, the mixture is cooled to room temperature, centrifuged, washed, vacuum dried and crushed to obtain grafted titanium dioxide. S2. Add grafted titanium dioxide to water and stir evenly, add a photoacid generator thereto and ultrasonically treat for 1-2 hours, spray dry, add 3,4-dihydroxystyrene polymer, 3-hydroxy-1-adamantyl methacrylate, alkaline additive, and leveling agent and mix evenly, add a solvent and mix evenly.

10. A method for using the photoresist composition according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: spin coating the photoresist composition according to any one of claims 1 to 8 on a silicon wafer, and sequentially performing pre-baking, exposure, post-baking and development to obtain a photolithographic pattern; The pre-baking temperature is 70-120°C and the exposure energy is 5-70mJ / cm 2 , post-baking temperature is 90-150℃; developing time is 30-130s.

Images