Developing photoresist-removing alkali-soluble photoresist and preparation method thereof

Abstract

The invention belongs to the technical field of photoresists, and particularly relates to an alkali-soluble photoresist capable of developing and removing photoresist and a preparation method of the alkali-soluble photoresist. The invention aims to solve the problem that complete alkali dissolution of the existing photoresist cannot be realized in two processes of developing and photoresist removing. The preparation method comprises the following steps: preparing a carboxyl filler precursor into a carboxylic filler through microemulsion polymerization, modifying a phenolic filler precursor with a coupling agent to obtain a phenolic filler, and carrying out copolymerization treatment on the carboxylic filler and the phenolic filler to generate an alkali-soluble filler; the water-soluble precursor is subjected to graft copolymerization to form a water-soluble polymeric monomer, the photoinitiator is pre-mixed with the water-soluble polymeric monomer at 10-20 DEG C after being subjected to surface functionalization modification, then the pre-mixed photoinitiator and the alkali-soluble filler are subjected to crosslinking copolymerization at 70 DEG C, and finally, the developing, photoresist-removing and alkali-soluble photoresist is obtained through decompression and defoaming. The developing and photoresist-removing alkali-soluble photoresist prepared by the invention can be completely alkali-soluble in developing and photoresist-removing links of a semiconductor etching process, so that the risk caused by organic pollutants in the etching process is reduced, and the developing and photoresist-removing alkali-soluble photoresist has a good application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of photoresists, and particularly relates to a photoresist that can be alkali-soluble during development and stripping, and a preparation method thereof. Background Art

[0002] Photoresist is an important raw material in the semiconductor industry. With the rapid development of the semiconductor industry, the development of photoresist technology has realized the transformation from traditional solvent-based to environmentally friendly alkali-soluble systems.

[0003] Although the existing alkali-soluble photoresists can be dissolved during the stripping stage by introducing hydroxyl or carboxyl functional groups, the removal of uncured photoresist during the development process still relies on organic solvents or mechanical stripping, resulting in the generation of oil stains and suspended solids or stripping residues in the process. This problem is particularly prominent in the bath circulation system, because the suspended hydrophobic residues are difficult to remove by conventional filtration, which not only pollutes the bath but also easily adheres to the surface of the silicon wafer, causing pattern defects.

[0004] At present, the inability of existing photoresists to achieve complete alkali solubility in both the development and stripping processes remains an important problem faced by the industry.

[0005] Therefore, a photoresist that can be alkali-soluble during development and stripping, and a preparation method thereof are proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a photoresist that can be alkali-soluble during development and stripping, and a preparation method thereof. In the present invention, a carboxyl filler precursor is prepared into a carboxylic acid-based filler through microemulsion polymerization, and a phenolic filler precursor is modified with a coupling agent to obtain a phenolic filler. The two are copolymerized to generate an alkali-soluble filler; a water-soluble precursor is subjected to graft copolymerization to form a water-soluble polymer monomer. After the photoinitiator is surface-functionalized and modified, it is premixed with the water-soluble polymer monomer at 10-20°C, and then cross-linked and copolymerized with the alkali-soluble filler at 70°C. Finally, a photoresist that can be alkali-soluble during development and stripping is obtained through reduced-pressure defoaming.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] A preparation method of a photoresist that can be alkali-soluble during development and stripping, comprising the following steps:

[0009] Unless otherwise specified, the parts in the present invention all refer to parts by mass, and the average molecular weight all refers to the number-average molecular weight.

[0010] Subject the carboxyl filler precursor to microemulsion polymerization to obtain a carboxylic acid-based filler;

[0011] Modify the phenolic filler precursor with a coupling agent to obtain a phenolic filler;

[0012] Subject the carboxylic acid-based filler and the phenolic filler to copolymerization treatment to obtain an alkali-soluble filler;

[0013] A water-soluble precursor is subjected to graft copolymerization to obtain a water-soluble polymer monomer;

[0014] Ethyl 2,4,6-trimethylbenzoyl phenylphosphonate is surface-functionalized to obtain a modified photoinitiator;

[0015] The modified photoinitiator and the water-soluble polymer monomer are premixed at 10-20 °C to obtain a prepolymer monomer;

[0016] The prepolymer monomer is mixed with an alkali-soluble filler, and after heating to 70 °C, crosslinking copolymerization is carried out to obtain a photoresist precursor;

[0017] After the photoresist precursor is degassed under reduced pressure, a photoresist that can be developed and de-gummed and is alkali-soluble is obtained.

[0018] Preferably, the carboxyl group filler includes: polyacrylate and polystyrene, wherein the number-average molecular weight of polyacrylate is 3000-5000, and the molecular weight of polystyrene is 2000-2500; the process of microemulsion polymerization is: 40 parts of polyacrylate, 5 parts of polystyrene and 1.2 parts of cetyltrimethylammonium bromide (CTAB) are dissolved in 200 parts of tetrahydrofuran, stirred and reacted at 50 °C at a rotation speed of 300-500 rpm for 30 min, then 0.4 part of ammonium persulfate is added, and the reaction is carried out at a reaction temperature of 85 °C and a reaction pH of 5.5-6.5 for 4 hours under nitrogen protection. After cooling to 25 °C, a carboxyl group filler is obtained.

[0019] Preferably, the phenolic group filler is bisphenol A novolac resin, its hydroxymethyl content is 42%, and its molecular weight is 2500-3500; the process of coupling agent modification is: 20 parts of bisphenol A novolac resin is dissolved in 100 parts of ethanol, 3 parts of KH550 is added, stirred at 60 °C for 2 hours, the ethanol is removed by rotary evaporation, and then vacuum dried at 80 °C for 2-4 hours to obtain a phenolic group filler.

[0020] Among them, KH550 refers to 3-aminopropyltriethoxysilane, and its CAS number is 919-30-2.

[0021] Preferably, the process of copolymerization treatment is: 58-63 parts of carboxyl group filler and 33-40 parts of phenolic group filler are jointly dispersed in 200 parts of tetrahydrofuran, maintaining a rotation speed of 270-350 rpm, 0.45 part of azobisisobutyronitrile is added, and the reaction is carried out at 120 °C and a reaction pressure of 1.5 MPa for 3 hours. The obtained product is washed with acetone and then dried to obtain an alkali-soluble filler.

[0022] Preferably, the water-soluble precursor includes hydroxyethyl acrylate and ethoxy acrylate; the process of graft copolymerization is as follows: 70 parts of hydroxyethyl acrylate and 30 parts of ethoxy acrylate are mixed evenly, deoxygenated with nitrogen for 30 min, then 200 parts of dichloromethane and 5 parts of methoxypolyethylene glycol are added. At a temperature of 80 °C, 0.07 part of EDTA and 0.03 part of sodium persulfate are added, and the mixture is stirred and reacted at a rotation speed of 400 - 700 rpm for 5 hours. After removing the solvent by vacuum distillation, a water-soluble monomer is obtained.

[0023] Among them, the average molecular weight of methoxypolyethylene glycol is 500.

[0024] Preferably, the process of surface functionalization is as follows: 50 parts of ethyl 2,4,6-trimethylbenzoyl phenylphosphonate and 57 - 61 parts of methacryloyl chloride are dissolved in 100 parts of DMF, and the mixture is stirred and reacted at a rotation speed of 500 rpm at 50 °C for 8 hours. After the obtained product is precipitated in n-hexane, it is dried in vacuum to obtain a modified photoinitiator.

[0025] Preferably, the process of premixing is as follows: the temperature is controlled at 10 - 20 °C, and 1.5 parts of the modified photoinitiator are added to 100 parts of the water-soluble polymer monomer in 3 portions at intervals of 5 min, and the mixture is stirred in the dark at a rotation speed of 200 rpm for 40 min to obtain a prepolymerized monomer.

[0026] Preferably, the process of crosslinking copolymerization is as follows: 100 parts of the prepolymerized monomer and 45 - 115 parts of alkali-soluble filler are uniformly dispersed at 25 °C, and the temperature is raised to 70 °C at a heating rate of 3 °C / min. Then, the mixture is kept warm at a stirring speed of 200 rpm for 2 hours. After adding 0.05 part of tetramethylethylenediamine, the temperature is lowered to 60 °C and the mixture is stirred and reacted at a rotation speed of 300 rpm for 40 min. After cooling to 25 °C, the organic solvent is removed by rotary evaporation to obtain a photoresist precursor.

[0027] Preferably, the process of vacuum degassing is as follows: the photoresist precursor is heated to 45 °C under an operating pressure of 0.2 atm, kept warm for 30 min, then the operating pressure is reduced to 0.05 - 0.1 atm, and the mixture is treated with ultrasonic waves at a frequency of 40 kHz for 15 min. After filtration, it is encapsulated to obtain an alkali-soluble photoresist for developing and removing photoresist.

[0028] An alkali-soluble photoresist for developing and removing photoresist includes: a modified initiator, a water-soluble polymer monomer, and an alkali-soluble filler.

[0029] The alkali-soluble photoresist for developing and removing photoresist provided by the present invention has the following characteristics: the acid value is 51 - 56 mg KOH / g, the viscosity is 242 - 257 cP, and the residual amount of bubbles < 0.05 vol%.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] 1. By compounding carboxylic acid-based fillers and phenolic fillers and controlling the molecular weight of the raw materials within a specific range, the good alkali solubility of the photoresist product in the development and stripping processes is achieved through segmented copolymerization treatment and crosslinked copolymerization process.

[0032] 2. Surface-functionalize the photoinitiator, and through step-by-step premixing and the design of the crosslinked copolymerization process, control the crosslinking density of the photoresist, synergistically improve the light response efficiency of the photoresist product, and ensure its good alkali solubility in both cured and uncured states.

[0033] 3. Through microemulsion polymerization treatment of the carboxyl filler precursor, coupling agent modification of the phenolic filler precursor, and graft copolymerization of the water-soluble precursor, jointly regulate the branch density of the polymer network in the photoresist product, and achieve the balance of product viscosity and fluidity.

[0034] 4. Through two-stage vacuum degassing treatment and controlling the addition amount of alkali-soluble fillers, effectively improve the purity and stability of the photoresist product at different application ratios, still ensure good alkali solubility after long-term storage, and have a low attenuation degree of light response efficiency. Description of the Drawings

[0035] Figure 1 It is the process flow chart of the preparation of the alkali-soluble photoresist for development and stripping in the present invention. Detailed Embodiments

[0036] The technical solutions of the present invention will be clearly and completely described below through some examples and experimental examples. Obviously, the described examples are only a part of the examples of the present invention, rather than all the examples. All other examples obtained by those of ordinary skill in the art based on the examples of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] Refer to Figure 1 As shown in the process flow chart, the present invention provides an alkali-soluble photoresist for development and stripping and its preparation method. The technical solutions are as follows:

[0038] Example 1

[0039] Dissolve 40 parts of polyacrylate, 5 parts of polystyrene and 1.2 parts of cetyltrimethylammonium bromide in 200 parts of tetrahydrofuran. After stirring and reacting at 50 °C at a speed of 300 rpm for 30 min, add 0.4 part of ammonium persulfate, and react at a reaction temperature of 85 °C and a reaction pH of 5.5 for 4 hours under nitrogen protection. After cooling to 25 °C, a carboxylic acid-based filler is obtained.

[0040] Dissolve 20 parts of bisphenol A phenolic resin in 100 parts of ethanol, add 3 parts of KH550, stir at 60 °C for 2 hours, remove the ethanol by rotary evaporation, and then vacuum dry at 80 °C for 2 hours to obtain the phenolic filler.

[0041] Disperse 58 parts of carboxyl group filler and 33 parts of phenolic filler in 200 parts of tetrahydrofuran together, maintain a rotation speed of 270 rpm, add 0.45 parts of azobisisobutyronitrile, react at 120 °C and a reaction pressure of 1.5 MPa for 3 hours, wash the obtained product with acetone and then dry it to obtain the alkali-soluble filler.

[0042] Mix 70 parts of hydroxyethyl acrylate and 30 parts of ethoxy acrylate evenly, purge with nitrogen to remove oxygen for 30 min, then add 200 parts of dichloromethane and 5 parts of polyethylene glycol monomethyl ether, add 0.07 parts of EDTA and 0.03 parts of sodium persulfate at 80 °C, and stir and react at a rotation speed of 400 rpm for 5 hours. After removing the solvent by vacuum distillation, a water-soluble polymer monomer is obtained.

[0043] Dissolve 50 parts of ethyl 2,4,6-trimethylbenzoyl phenylphosphinate (TPO-L) and 57 - 61 parts of methacryloyl chloride in 100 parts of DMF, stir and react at 50 °C at a rotation speed of 500 rpm for 8 hours. After the obtained product is precipitated in n-hexane, it is vacuum dried to obtain the modified photoinitiator.

[0044] Control the temperature at 10 - 20 °C, add 1.5 parts of the modified photoinitiator to 100 parts of the water-soluble polymer monomer in 3 portions at intervals of 5 min, stir in the dark at a rotation speed of 200 rpm for 40 min to obtain the prepolymerized monomer.

[0045] Disperse 100 parts of the prepolymerized monomer and 45 parts of the alkali-soluble filler evenly at 25 °C, heat up to 70 °C at a heating rate of 3 °C / min, then keep the temperature at 200 rpm for 2 hours, add 0.05 parts of tetramethylethylenediamine (TEMED), cool down to 60 °C and stir and react at a rotation speed of 300 rpm for 40 min. After cooling to 25 °C, remove the organic solvent by rotary evaporation to obtain the photoresist precursor.

[0046] Heat the photoresist precursor to 45 °C under an operating pressure of 0.2 atm, keep the temperature for 30 min, then reduce the operating pressure to 0.05 atm, treat it at an ultrasonic frequency of 40 kHz for 15 minutes, filter and then encapsulate to obtain the alkali-soluble photoresist for developing and removing the photoresist.

[0047] The acid value of the prepared photoresist product is 51 mg KOH / g, the viscosity is 242 cP, and the residual amount of bubbles is 0.2 vol%.

[0048] Example 2-20 is different from Example 1 in terms of operating parameters, and there are slight differences in the physical properties of the obtained photoresist products. The specific parameter and property changes are summarized in Tables 1 and 2.

[0049] Table 1 Changes in Operating Parameters of Examples 1-20 (I)

[0050]

[0051]

[0052] Table 2 Changes in Operating Parameters of Examples 1-20 (II) and Changes in Physical Properties

[0053]

[0054]

[0055] Different addition amounts of alkali-soluble fillers will affect the viscosity and acid value of the photoresist product, but they are within a reasonable range of a small scale. Alkali-soluble fillers exceeding the reasonable addition amount range will affect other key properties of the photoresist product.

[0056] Comparative Example 1

[0057] Different from Example 1, no carboxylic acid group filler is added, and an equal amount of unmodified phenolic filler is used instead, and other process parameters are the same.

[0058] Comparative Example 2

[0059] Different from Example 1, the average molecular weight of polyacrylate in the raw materials is 8000, and other process parameters are the same.

[0060] Comparative Example 3

[0061] Different from Example 1, the reaction pressure in the copolymerization reaction stage is reduced to 101.325 kPa, and other process parameters are the same.

[0062] Comparative Example 4

[0063] Different from Example 6, un-surface-functionalized TPO-L is used as the photoinitiator, and other process parameters are the same.

[0064] Comparative Example 5

[0065] Different from Example 6, all the modified photoinitiator is added once in the premixing stage, and other process parameters are the same.

[0066] Comparative Example 6

[0067] Different from Example 6, TEMED is not added in the crosslinking copolymerization stage, and other process parameters are the same.

[0068] Comparative Example 7

[0069] Different from Example 11, the amount of CTAB used in the microemulsion polymerization of the carboxylic acid group filler was reduced to 0.2 parts, and other process parameters were the same.

[0070] Comparative Example 8

[0071] Different from Example 11, polyethylene glycol monomethyl ether was not added, and other process parameters were the same.

[0072] Comparative Example 9

[0073] Different from Example 11, during the graft copolymerization process, the reaction temperature was changed to 50 °C, and other process parameters were the same.

[0074] Comparative Example 10

[0075] Different from Example 16, in the vacuum degassing stage, it was only kept warm at 0.2 atm and 45 °C for 30 min without ultrasonic assistance, and other process parameters were the same.

[0076] Comparative Example 11

[0077] Different from Example 16, the addition amount of the alkali-soluble filler was increased to 200 parts, and other process parameters were the same.

[0078] Experimental Example 1

[0079] The alkali solubility of the photoresists prepared in Examples 1-5 and Comparative Examples 1-3 was tested in the development and stripping processes, and the relevant results are summarized in Table 3.

[0080] In the development stage, the uncured part of the negative photoresist provided by the present invention can be quickly dissolved in a weakly alkaline environment; in the stripping stage, the cured negative photoresist provided by the present invention can be quickly dissolved in a strongly alkaline environment under heating.

[0081] The test method for the alkali solubility of the photoresist in the development process is as follows: The photoresist product is coated on a silicon wafer substrate, and the coating thickness is maintained at 2 μm. After baking at 90 °C for 1 min, exposure dose treatments of 0, 10, 20, 30, 40, and 50 mJ / cm 2 are carried out respectively. After developing with a 0.26 N tetramethylammonium hydroxide solution for 40 s, the thickness loss corresponding to each exposure dose is recorded. The dissolution rate is used to represent the alkali solubility of the photoresist in the development process. The dissolution rate DR = (initial thickness - thickness after development) / development time. The larger the value of DR, the better the alkali solubility of the corresponding treated photoresist in the development process. The negative photoresist provided by the present invention should have the lowest alkali solubility after exposure treatment, and the highest alkali solubility for the unexposed photoresist.

[0082] The method for testing the alkali solubility of photoresist in the ashing process is as follows: coat the photoresist product on a silicon wafer substrate, keep the coating thickness at 2 μm, bake it at 90 °C for 1 min, and then use an exposure dose of 50 mJ / cm 2 . After treatment, develop it with a 0.26 N tetramethylammonium hydroxide solution for 40 s, soak it in N-methylpyrrolidone (NMP) at 80 °C, and record the time when the cured photoresist is completely dissolved. The shorter the complete dissolution time, the better the alkali solubility in the ashing process.

[0083] Table 3 Alkali solubility of the photoresists prepared in Examples 1-5 and Comparative Examples 1-3 in the developing and ashing processes

[0084]

[0085]

[0086] As shown by the alkali solubility data in Table 3, the photoresists prepared in Examples 1-5 can be quickly dissolved in a low-alkali environment at a low curing degree. As the curing degree increases, it becomes increasingly difficult for the low-alkalinity solvent to dissolve the photoresist product. After curing is completed, the sample photoresist will not be dissolved in the low-alkalinity environment. That is, in the developing process, the uncured photoresist is completely soluble, and the cured photoresist is completely insoluble; under the ashing process conditions, the completely cured photoresist can also be quickly dissolved. Therefore, Examples 1-5 have good alkali solubility in both the developing and ashing processes.

[0087] In Comparative Example 1, due to the absence of carboxylic acid-based fillers, the DR showed a cliff-like drop after exposure, indicating that the presence of carboxylic acid groups accelerates the dissolution of the uncured area through hydrophilic carboxyl groups, resulting in insufficient solubility in the developing process; and in the ashing process, it takes a longer dissolution time to be completely dissolved. In Comparative Example 2, due to the relatively large molecular weight of polyacrylate, it had similar experimental phenomena to Comparative Example 1, and the solubility decreased in both processes. Comparative Example 3 changed the copolymerization temperature, resulting in a loose internal polymer structure of the formed photoresist. It did not have significant selectivity in the developing process, the uncured photoresist could not be quickly dissolved, and the cured photoresist could not be completely insoluble either. It also took more time to be completely dissolved in the ashing process.

[0088] In summary, the alkali solubility of photoresist needs to be differentially regulated at different process stages. The carboxyl group fillers construct a rapid dissolution channel through acid value regulation, and with the precise molecular weight control of the polymer raw materials in the fillers, the dispersion of the fillers is optimized, and a crosslinked network with a suitable density is obtained through high-pressure reaction copolymerization, thereby achieving the effects that the cured photoresist is insoluble in the development stage, the uncured photoresist is soluble, and the cured photoresist can be rapidly dissolved in the stripping stage. That is, through the compounding of carboxyl group fillers and phenolic group fillers and controlling the molecular weight of the raw materials within a specific range, the good alkali solubility of the photoresist product in the development and stripping processes is jointly achieved through segmented copolymerization treatment and crosslinked copolymerization process.

[0089] Experimental Example 2

[0090] The alkali solubility of the photoresists prepared in Examples 6-10 and Comparative Examples 4-6 in the development and stripping processes was tested, and the relevant results are summarized in Table 4.

[0091] The test method refers to Experimental Example 1.

[0092] Table 4 Alkali solubility of the photoresists prepared in Examples 6-10 and Comparative Examples 4-6 in the development and stripping processes

[0093]

[0094] As shown by the alkali solubility data in Table 4, the photoresists prepared in Examples 6-10 have similar characteristics to those in Examples 1-5. In the development process, the uncured photoresist is completely soluble, and the cured photoresist is completely insoluble; under the stripping process conditions, the fully cured photoresist can also be rapidly dissolved, and Examples 6-10 also have good alkali solubility in both the development and stripping processes.

[0095] In Comparative Example 4, due to the lack of surface functionalization of the photoinitiator, it has a high solubility regardless of curing in the development process, resulting in a significant decline in the performance of the product photoresist. In Comparative Example 5, due to the single addition of the photoinitiator, the dispersion is significantly reduced, resulting in the agglomeration of the dispersant during the curing process, the decline of the development effect, and the deterioration of the photo-responsiveness of the photoresist, making it impossible to effectively distinguish between cured and uncured photoresists in a low-alkali environment, and it takes a longer time to completely dissolve in the stripping process. In Comparative Example 6, due to the absence of TEMED, the crosslinking density is too low, and the alkali solubility is too high during the development process, which cannot ensure that the cured photoresist is not dissolved by alkali, and it takes a longer process to completely dissolve in the stripping process.

[0096] In summary, functionalized TPO-L can effectively anchor polymer chains, keeping the segment distance appropriate. While maintaining a sensitive photoinitiation responsiveness, the cured photoresist has an appropriate crosslinking density. Through stepwise premixing and crosslinking copolymerization processes, the crosslinking density of the photoresist is further controlled, synergistically enhancing the photo-response efficiency of the photoresist product and ensuring good alkali solubility in both cured and uncured states.

[0097] Experimental Example 3

[0098] The viscosities and fluidities of the photoresists prepared in Examples 11 - 15 and Comparative Examples 7 - 9 were tested, and the relevant results are summarized in Table 5.

[0099] The test method for viscosity is as follows: Place the photoresist sample in a constant temperature water bath, keep the temperature stable at 25°C, and measure it with a rotational viscometer at 60 rpm. The RV-1 rotor is selected. Record the viscosity (cP) data.

[0100] The test method for fluidity is as follows: Drop 0.1 mL of the photoresist sample onto a silicon wafer placed at a 30° inclination, and record the flow distance (cm) of the photoresist sample after natural flow for 60 s at 25°C. The larger the flow distance, the better the fluidity of the photoresist.

[0101] Table 6 Viscosities and Fluidities of the Photoresists Prepared in Examples 11 - 15 and Comparative Examples 7 - 9

[0102] Viscosity (cP) Flow distance (cm) Example 11 255 7.8 Example 12 247 8.2 Example 13 256 8.6 Example 14 249 7.5 Example 15 253 8.0 Comparative Example 7 178 13.2 Comparative Example 8 362 5.1 Comparative Example 9 154 12.1

[0103] As shown in the viscosity and fluidity data in Table 6, the photoresists prepared in Examples 11 - 15 have appropriate viscosities and fluidities, and can complete coating, curing, and development well. In Comparative Example 7, due to the reduction in the amount of CTAB, the crosslinking density decreased, resulting in a decrease in viscosity and an increase in fluidity. In Comparative Example 8, because polyethylene glycol monomethyl ether was not added, the viscosity of the product increased and the fluidity became poor. In Comparative Example 9, due to the decrease in the reaction temperature during the graft copolymerization process, the crosslinking density of the photoresist product decreased significantly, the viscosity decreased accordingly, and the fluidity was too high.

[0104] In summary, through the microemulsion polymerization of carboxyl filler precursors, the coupling agent modification of phenolic filler precursors, and the graft copolymerization process of water-soluble precursors, the crosslinking degree and interaction of polymer segments inside the photoresist are synergistically regulated, and a three-dimensional crosslinking network with an appropriate density is controlled to form, making the product photoresist have appropriate viscosities and fluidities, and achieving the balance of product viscosity and fluidity.

[0105] Experimental Example 4

[0106] The storage stabilities of the photoresists prepared in Examples 16-20 and Comparative Examples 10-11 are summarized in Table 7.

[0107] The test method for storage stability is as follows: referring to the test methods of Experimental Example 1 and Experimental Example 3, the alkali solubility test and viscosity test in the photoresist stripping process are carried out on the sample photoresist. After storing the sample at 60 °C for 14 days, the alkali solubility test and viscosity test in the photoresist stripping process are repeated, and the obtained results are recorded.

[0108] Table 7 Storage Stabilities of the Photoresists Prepared in Examples 16-20 and Comparative Examples 10-11

[0109]

[0110] As shown in the storage stability data in Table 7, the photoresists prepared in Examples 16-20 had good alkali solubility and moderate viscosity before the storage test. After the storage test, the alkali solubility decreased slightly, but still had good performance. The viscosities also decreased slightly, but did not significantly affect their performance. In Comparative Example 10, since only one-stage vacuum degassing treatment was carried out, the viscosity before the storage test increased slightly, the alkali solubility decreased significantly after the storage test, and the viscosity increased significantly. In Comparative Example 11, due to the excessive addition of the alkali-soluble filler, the viscosity increased significantly, the increase in viscosity after the storage test was greater, and the alkali solubility also decreased significantly.

[0111] In summary, the alkali-soluble filler within a reasonable addition range improves the alkali solubility of the photoresist product while ensuring that key physical parameters such as the viscosity of the photoresist product are within a reasonable range. Combining the vacuum degassing treatment in two stages effectively improves the purity and stability of the photoresist product at different application ratios. After long-term storage, good alkali solubility can still be ensured, and the attenuation degree of the light response efficiency is low.

[0112] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation method of a photoresist that can be developed, de-glued, and alkali-soluble, characterized in that: The preparation method is as follows: The carboxyl filler precursor is subjected to microemulsion polymerization to obtain a carboxyl group filler; The phenolic filler precursor is modified with a coupling agent to obtain a phenolic filler; The carboxyl group filler and the phenolic filler are subjected to copolymerization treatment to obtain an alkali-soluble filler; The water-soluble precursor is subjected to graft copolymerization to obtain a water-soluble polymer monomer; 2,4,6-Trimethylbenzoyl diphenylphosphine ethyl ester is surface-functionalized to obtain a modified photoinitiator; The modified photoinitiator and the water-soluble polymer monomer are premixed at 10-20 °C to obtain a prepolymer monomer; 100 parts of the prepolymer monomer and 45-115 parts of the alkali-soluble filler are uniformly dispersed and then subjected to crosslinking copolymerization to obtain a photoresist precursor; The photoresist precursor is degassed under reduced pressure to obtain the developable and alkali-soluble photoresist.

2. The preparation method of a developable and alkali-soluble photoresist according to claim 1, characterized in that: The carboxyl filler precursor includes: polyacrylate and polystyrene, wherein the number average molecular weight of the polyacrylate is 3000-5000; the process of microemulsion polymerization is: the polyacrylate, the polystyrene and cetyltrimethylammonium bromide are dissolved in tetrahydrofuran, stirred and reacted at a speed of 300-500 rpm for 30 min, ammonium persulfate is added, and the reaction is carried out at a reaction temperature of 85 °C and a reaction pH of 5.5-6.5 for 4 hours under nitrogen protection, and the carboxyl group filler is obtained after cooling.

3. The preparation method of a developable and alkali-soluble photoresist according to claim 1, characterized in that: The phenolic filler precursor is bisphenol A novolac resin, and the hydroxymethyl content of the bisphenol A novolac resin is 42%; the process of coupling agent modification is: by mass, 20 parts of the bisphenol A novolac resin is dissolved in 100 parts of ethanol, 3 parts of KH550 is added, stirred at 60 °C for 2 hours, the ethanol is removed by rotary evaporation, and then vacuum dried at 80 °C for 2-4 hours to obtain the phenolic filler.

4. The preparation method of a developable and alkali-soluble photoresist according to claim 1, characterized in that: The process of copolymerization treatment is: by mass, 58-63 parts of the carboxyl group filler and 33-40 parts of the phenolic filler are jointly dispersed in 200 parts of tetrahydrofuran, the rotation speed is maintained at 270-350 rpm, 0.45 part of azobisisobutyronitrile is added, and the reaction is carried out at 120 °C and a reaction pressure of 1.5 MPa for 3 hours. The obtained product is washed with acetone and dried to obtain the alkali-soluble filler.

5. The preparation method of a developable and alkali-soluble photoresist according to claim 1, characterized in that: The water-soluble precursor includes hydroxyethyl acrylate and ethoxy acrylate; the process of graft copolymerization is: by mass, the hydroxyethyl acrylate and ethoxy acrylate are mixed evenly, nitrogen is introduced to remove oxygen, dichloromethane and polyethylene glycol monomethyl ether are added, EDTA and sodium persulfate are added at a temperature of 80 °C, and the reaction is stirred at a speed of 400-700 rpm for 5 hours, and the solvent is removed by vacuum distillation to obtain the water-soluble polymer monomer.

6. The preparation method of a developable and alkali-soluble photoresist according to claim 1, characterized in that: The process of surface functionalization is: by mass, 50 parts of 2,4,6-trimethylbenzoyl diphenylphosphine ethyl ester and 57-61 parts of methacryloyl chloride are dissolved in 100 parts of DMF, stirred and reacted at 50 °C at a speed of 500 rpm for 8 hours. The obtained product is precipitated in n-hexane and then vacuum dried to obtain the modified photoinitiator.

7. The preparation method of a developable and alkali-soluble photoresist according to claim 1, characterized in that: The process of the pre-mixing is as follows: by mass parts, controlling the temperature at 10 - 20 °C, adding 1.5 parts of the modified photoinitiator into 100 parts of the water-soluble polymer monomer in three times at intervals of 5 minutes, and stirring in the dark at a rotation speed of 200 rpm for 40 minutes to obtain a prepolymer monomer.

8. The preparation method of a developable and alkali-soluble photoresist according to claim 1, characterized in that: The process of the reduced-pressure defoaming is as follows: heating the photoresist precursor to 45 °C under an operating pressure of 0.2 atm, keeping the temperature for 30 minutes, then reducing the operating pressure to 0.05 - 0.1 atm, treating with an ultrasonic frequency of 40 kHz for 15 minutes, and filtering and encapsulating to obtain the alkali-soluble photoresist for developing and removing the photoresist.

9. A photoresist that is developable, strippable, and alkali-soluble, characterized in that: The alkali-soluble photoresist for developing and removing the photoresist is prepared by the preparation method according to any one of claims 1 - 8; The alkali-soluble photoresist for developing and removing the photoresist comprises: a modified photoinitiator, a water-soluble polymer monomer, and an alkali-soluble filler.

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