A method for developing a photoresist which is alkali-soluble after removal of a photoresist

Abstract

The present application belongs to the technical field of photoresist, and particularly relates to a preparation method of a photoresist which can be alkali-dissolved in development and removal processes. The present application aims to solve the problem that the existing photoresist cannot be completely alkali-dissolved in the development and removal processes. In the present application, a carboxyl filler precursor is prepared into a carboxylic acid filler through microemulsion polymerization, a phenolic filler precursor is modified by a coupling agent to obtain a phenolic filler, and the two are copolymerized to obtain an alkali-soluble filler; a water-soluble precursor is grafted and copolymerized to form a water-soluble polymer monomer, a photoinitiator is surface-functionalized and modified, and then is premixed with the water-soluble polymer monomer at 10-20 DEG C, and then is crosslinked and copolymerized with the alkali-soluble filler at 70 DEG C, and finally is deaerated under reduced pressure to obtain the photoresist which can be alkali-dissolved in development and removal processes. The photoresist prepared by the present application can be completely alkali-dissolved in the development and removal processes of the semiconductor etching process, reduces the risk caused by organic pollutants in the etching process, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photoresist and particularly relates to a preparation method of a developing and debinding alkali-soluble photoresist. BACKGROUND

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

[0003] Although the existing alkali-soluble photoresist can realize the debinding stage by introducing hydroxyl or carboxyl functional groups, the removal of the unhardened photoresist in the developing stage still depends on organic solvents or mechanical stripping, resulting in oil stains, suspended substances or stripping residues in the process. This problem is particularly prominent in the tank liquid circulation system, because the suspended hydrophobic residues are difficult to remove by conventional filtration, which not only pollutes the tank liquid but also easily adheres to the surface of the silicon wafer to cause pattern defects.

[0004] At present, the existing photoresist cannot realize complete alkali-solubility in the developing and debinding processes, which is still an important problem faced by the industry.

[0005] Therefore, a preparation method of a developing and debinding alkali-soluble photoresist is provided. SUMMARY

[0006] The application aims to provide a preparation method of a developing and debinding alkali-soluble photoresist. In the application, the carboxyl filler precursor is prepared into a carboxylic acid filler by microemulsion polymerization, the phenolic filler precursor is modified by a coupling agent to obtain a phenolic filler, and the two are copolymerized to obtain an alkali-soluble filler; the water-soluble precursor is grafted and copolymerized to form a water-soluble polymer monomer, the photoinitiator is surface-functionalized and modified, and then is premixed with the water-soluble polymer monomer at 10-20 DEG C, and then is crosslinked and copolymerized with the alkali-soluble filler at 70 DEG C, and finally is deaerated under reduced pressure to obtain the developing and debinding alkali-soluble photoresist.

[0007] To achieve the above-mentioned purpose, the application provides the following technical scheme:

[0008] A preparation method of a developing and debinding alkali-soluble photoresist, comprising the following steps:

[0009] Unless otherwise specified, the parts in the application refer to mass parts, and the average molecular weight refers to the average molecular weight.

[0010] The carboxyl filler precursor is subjected to microemulsion polymerization to obtain a carboxylic acid filler;

[0011] The phenolic filler precursor is modified by a coupling agent to obtain a phenolic filler;

[0012] The carboxylic acid filler and the phenolic filler are subjected to copolymerization treatment to obtain an alkali-soluble filler;

[0013] The water-soluble precursor is obtained by graft copolymerization to obtain a water-soluble polymer monomer;

[0014] The 2,4,6-trimethylbenzoyl phenyl ethyl phosphonate is surface functionalized to obtain a modified photoinitiator;

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

[0016] The pre-polymer monomer is mixed with an alkali-soluble filler, heated to 70°C, and then cross-linked copolymerization to obtain a photoresist precursor;

[0017] The photoresist precursor is deaerated under reduced pressure to obtain a photoresist that can be developed and removed with alkali.

[0018] Preferably, the carboxyl filler includes polyacrylate and polystyrene, wherein the number average molecular weight of the polyacrylate is 3000-5000, and the molecular weight of the polystyrene is 2000-2500; the microemulsion polymerization process is as follows: 40 parts of polyacrylate, 5 parts of polystyrene, and 1.2 parts of cetyltrimethylammonium bromide (CTAB) are dissolved in 200 parts of tetrahydrofuran, stirred at 50°C at a speed of 300-500 rpm for 30 min, then 0.4 parts 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, and then cooled to 25°C to obtain the carboxyl filler.

[0019] Preferably, the phenolic filler is bisphenol A phenolic resin, the hydroxymethyl content of which is 42%, and the molecular weight is 2500-3500; the coupling agent modification process is as follows: 20 parts of bisphenol A phenolic 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.

[0020] KH550 refers to 3-aminopropyl triethoxysilane, and the CAS number is 919-30-2.

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

[0022] Preferably, the water-soluble precursor comprises hydroxyethyl acrylate and ethoxy acrylate; the graft copolymerization process is as follows: 70 parts of hydroxyethyl acrylate and 30 parts of ethoxy acrylate are uniformly mixed, oxygen is removed by nitrogen for 30 min, 200 parts of dichloromethane and 5 parts of polyethylene glycol monomethyl ether are added, 0.07 parts of EDTA and 0.03 parts of sodium persulfate are added at a temperature of 80℃, stirring is carried out at a speed of 400-700 rpm for 5 hours, and then the solvent is removed by distillation under reduced pressure to obtain a water-soluble monomer.

[0023] Preferably, the average molecular weight of the polyethylene glycol monomethyl ether is 500.

[0024] Preferably, the surface functionalization process is as follows: 50 parts of 2,4,6-trimethyl benzoyl phenyl phosphonic acid ethyl ester and 57-61 parts of methacryloyl chloride are dissolved in 100 parts of DMF, stirring is carried out at a speed of 500 rpm at a temperature of 50℃ for 8 hours, the obtained product is precipitated in n-hexane, and then vacuum drying is carried out to obtain a modified photoinitiator.

[0025] Preferably, the premixing process is as follows: the temperature is controlled at 10-20℃, 1.5 parts of the modified photoinitiator is added into 100 parts of the water-soluble polymerized monomer in three times with an interval of 5 min, and then stirring is carried out in the dark at a speed of 200 rpm for 40 min to obtain a pre-polymerized monomer.

[0026] Preferably, the crosslinking copolymerization process is as follows: 100 parts of the pre-polymerized monomer and 45-115 parts of the alkali-soluble filler are uniformly dispersed at a temperature of 25℃, the temperature is raised to 70℃ at a raising rate of 3℃ / min, and then the temperature is kept for 2 hours at a stirring speed of 200 rpm, 0.05 parts of tetramethyl ethylenediamine is added dropwise, the temperature is lowered to 60℃, stirring is carried out at a speed of 300 rpm for 40 min, and then the organic solvent is removed by rotary evaporation after the temperature is lowered to 25℃ to obtain a photoresist precursor.

[0027] Preferably, the process of degassing under reduced pressure is as follows: the photoresist precursor is raised to a temperature of 45℃ under an operating pressure of 0.2 atm, the temperature is kept for 30 min, the operating pressure is lowered to 0.05-0.1 atm, and then ultrasonic treatment is carried out at a frequency of 40 kHz for 15 min, and then the photoresist precursor is filtered and packaged to obtain a photoresist which can be developed and removed by alkali.

[0028] A photoresist which can be developed and removed by alkali, comprising: a modified initiator, a water-soluble polymerized monomer and an alkali-soluble filler.

[0029] The photoresist which can be developed and removed by alkali provided by the application 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 is <0.05 vol%.

[0030] Compared with the prior art, the photoresist which can be developed and removed by alkali provided by the application has the following beneficial effects:

[0031] By compounding the carboxylic acid-based filler and the phenolic-based filler, and controlling the molecular weight of the raw material in a specific range, the good alkali solubility of the photoresist product in the development and stripping process is realized by the segmented copolymerization process and the crosslinking copolymerization process.

[0032] The surface of the photoinitiator is functionalized, and by step-by-step premixing and the design of the crosslinking copolymerization process, the crosslinking density of the photoresist is controlled, which cooperatively improves the light response efficiency of the photoresist product, and ensures that it has good alkali solubility in the cured and uncured states.

[0033] By microemulsion polymerization treatment of the carboxyl filler precursor, and coupling agent modification of the phenolic filler precursor, and graft copolymerization of the water-soluble precursor, the branch density of the polymer network in the photoresist product is cooperatively adjusted, and the balance of the product viscosity and fluidity is realized.

[0034] By two-stage vacuum degassing treatment and controlling the addition amount of the alkali-soluble filler, the purity and stability of the photoresist product under different application ratios are effectively improved, and after long-term storage, the alkali solubility is still good, and the light response efficiency decay degree is low. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The process flow chart for preparing the alkali-soluble photoresist for development and stripping in the present application is shown. DETAILED DESCRIPTION

[0036] The technical solutions of the present application will be described below by some embodiments and experimental examples, obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0037] Referring to Figure 1 The process flow chart is shown, the present application provides a preparation method of an alkali-soluble photoresist for development and stripping, the technical scheme is as follows:

[0038] Example 1

[0039] 40 parts of polyacrylate, 5 parts of polystyrene and 1.2 parts of cetyltrimethylammonium bromide were dissolved in 200 parts of tetrahydrofuran, and after stirring at 50℃ for 30min at a speed of 300rpm, 0.4 parts of ammonium persulfate was added, and the reaction was carried out at a reaction temperature of 85℃ and a reaction pH of 5.5 for 4 hours, and then cooled to 25℃ to obtain the carboxylic acid-based filler.

[0040] The phenolic filler was prepared by dissolving 20 parts of bisphenol A novolac resin in 100 parts of ethanol, adding 3 parts of KH550, stirring at 60°C for 2 hours, removing the ethanol by rotary evaporation, and vacuum drying at 80°C for 2 hours.

[0041] The alkali-soluble filler was prepared by dispersing 58 parts of carboxyl-based filler and 33 parts of phenolic filler in 200 parts of tetrahydrofuran, adding 0.45 parts of azobisisobutyronitrile at a stirring speed of 270 rpm, and reacting at 120°C and a reaction pressure of 1.5 MPa for 3 hours. The product was washed with acetone and dried to obtain the alkali-soluble filler.

[0042] The water-soluble polymerized monomer was prepared by uniformly mixing 70 parts of hydroxyethyl acrylate and 30 parts of ethoxy acrylate, purging oxygen with nitrogen for 30 minutes, adding 200 parts of dichloromethane and 5 parts of polyethylene glycol monomethyl ether, adding 0.07 parts of EDTA and 0.03 parts of sodium persulfate at 80°C, stirring at a speed of 400 rpm for 5 hours, and removing the solvent by distillation under reduced pressure.

[0043] The modified photoinitiator was prepared by dissolving 50 parts of 2,4,6-trimethylbenzoyl phenyl ethyl phosphonate (TPO-L) and 57-61 parts of methacryloyl chloride in 100 parts of DMF, stirring at 50°C and a speed of 500 rpm for 8 hours, precipitating the product in n-hexane, and vacuum drying to obtain the modified photoinitiator.

[0044] The pre-polymerized monomer was prepared by adding 1.5 parts of the modified photoinitiator to 100 parts of the water-soluble polymerized monomer at intervals of 5 minutes, stirring at a speed of 200 rpm for 40 minutes in the dark at a temperature of 10-20°C, and then cooling to room temperature.

[0045] The photoresist precursor was prepared by uniformly dispersing 100 parts of the pre-polymerized monomer and 45 parts of the alkali-soluble filler at 25°C, heating to 70°C at a heating rate of 3°C / min, stirring at a speed of 200 rpm for 2 hours, adding 0.05 parts of tetramethyl ethylenediamine (TEMED), stirring at a speed of 300 rpm for 40 minutes after cooling to 60°C, and then removing the organic solvent by rotary evaporation after cooling to 25°C.

[0046] The alkali-soluble photoresist was prepared by heating the photoresist precursor to 45°C at an operating pressure of 0.2 atm, maintaining the temperature for 30 minutes, reducing the operating pressure to 0.05 atm, treating with ultrasonic waves at a frequency of 40 kHz for 15 minutes, and then filtering and packaging.

[0047] The prepared photoresist product had an acid value of 51 mg KOH / g, a viscosity of 242 cP, and a residual bubble content of 0.2 vol%.

[0048] Example 2-20 has different operating parameters from Example 1, and the obtained photoresist products have slight differences in physical properties. The specific parameter and property changes are summarized in Table 1 and Table 2.

[0049] Table 1 Changes in operating parameters of Examples 1-20 (I)

[0050]

[0051] Table 2 Changes in operating parameters and physical properties of Examples 1-20 (II)

[0052]

[0053] Different amounts of alkali-soluble filler affect the viscosity and acid value of the photoresist product, but within a small range of reasonable intervals. Alkali-soluble fillers exceeding the reasonable addition amount range will affect other key properties of the photoresist product.

[0054] Comparative Example 1

[0055] Unlike Example 1, no carboxyl-based filler is added, and an equal amount of unmodified phenolic filler is used instead. Other process parameters are the same.

[0056] Comparative Example 2

[0057] Unlike Example 1, the average molecular weight of the polyacrylate in the raw material is 8000. Other process parameters are the same.

[0058] Comparative Example 3

[0059] Unlike Example 1, the reaction pressure drop during the copolymerization stage is 101.325 kPa. Other process parameters are the same.

[0060] Comparative Example 4

[0061] Unlike Example 6, TPO-L without surface functionalization is used as a photoinitiator. Other process parameters are the same.

[0062] Comparative Example 5

[0063] Unlike Example 6, all the modified photoinitiators are added at once during the premixing stage. Other process parameters are the same.

[0064] Comparative Example 6

[0065] Unlike Example 6, no TEMED is added during the crosslinking copolymerization stage. Other process parameters are the same.

[0066] Comparative Example 7

[0067] Different from example 11, the amount of CTAB in the microemulsion polymerization of carboxyl group filler is reduced to 0.2 parts, and other process parameters are the same.

[0068] Comparative example 8

[0069] Different from example 11, no polyethylene glycol monomethyl ether is added, and other process parameters are the same.

[0070] Comparative example 9

[0071] Different from example 11, the reaction temperature in the graft copolymerization process is changed to 50℃, and other process parameters are the same.

[0072] Comparative example 10

[0073] Different from example 16, the vacuum defoaming stage is only incubated at 0.2 atm and 45℃ for 30 min, and no ultrasonic auxiliary treatment is performed, and other process parameters are the same.

[0074] Comparative example 11

[0075] Different from example 16, the amount of alkali-soluble filler is increased to 200 parts, and other process parameters are the same.

[0076] Experimental example 1

[0077] The alkali solubility of the photoresists prepared in examples 1-5 and comparative examples 1-3 in the development and stripping process is tested, and the related results are summarized in table 3.

[0078] In the development stage, the uncured part of the negative photoresist provided by the application can be quickly dissolved in a weak alkaline environment; in the stripping stage, the cured negative photoresist provided by the application is quickly dissolved in a strong alkaline environment under heating.

[0079] 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, the coating thickness is kept at 2μm, after baking at 90℃ for 1 min, 0, 10, 20, 30, 40, 50mJ / cm 2 of exposure dose treatment is performed, and after 0.26N tetramethylammonium hydroxide solution is developed for 40s, 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 photoresist in the development process. The negative photoresist provided by the application should have the lowest alkali solubility after exposure treatment, and the photoresist without exposure treatment has the highest alkali solubility.

[0080] The test method for alkali solubility of photoresist in the stripping process is as follows: the photoresist product is coated on a silicon wafer substrate, the coating thickness is kept at 2 μm, after baking at 90 °C for 1 min, after treatment with an exposure dose of 50 mJ / cm 2 , development treatment with 0.26N tetramethylammonium hydroxide solution for 40 s, soaking treatment with N-methyl pyrrolidone (NMP) at 80 °C, and the time for complete dissolution of the cured photoresist is recorded. The shorter the complete dissolution time, the better the alkali solubility in the stripping process.

[0081] Table 3 Alkali solubility of photoresists prepared in Examples 1-5 and Comparative Examples 1-3 in development and stripping processes

[0082]

[0083] As shown in the alkali solubility data in Table 3, the photoresists prepared in Examples 1-5 can be quickly dissolved in a low-alkalinity environment at a low degree of curing, and as the degree of curing increases, it becomes more and more difficult for low-alkalinity solvents to dissolve the photoresist product. When curing is complete, the sample photoresist cannot be dissolved in a low-alkalinity environment, i.e. in the development process, the uncured photoresist is completely soluble, and the cured photoresist is completely insoluble; in the stripping process, the completely cured photoresist can also be quickly dissolved. Therefore, Examples 1-5 have good alkali solubility in both development and stripping processes.

[0084] Comparative Example 1 has a sharp drop in DR after exposure due to the absence of carboxylic acid-based fillers, 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 development process; and in the stripping process, a long dissolution time is required for complete dissolution. Comparative Example 2 has similar experimental phenomena as Comparative Example 1 due to the large molecular weight of the polyacrylate, and the solubility in both processes decreases. Comparative Example 3 changes the copolymerization temperature, resulting in a loose internal polymer structure of the photoresist, which does not have significant selectivity in the development process, the uncured photoresist cannot be quickly dissolved, the cured photoresist is not completely insoluble, and more time is required for complete dissolution in the stripping process.

[0085] In summary, the alkali solubility of photoresist in different process stages needs to be differentiated and regulated. The carboxylic acid-based filler controls the construction of a fast-dissolving channel through acid value, and the dispersion of the filler is optimized through precise control of the molecular weight of the high-molecular-weight raw material in the filler, and a crosslinked network with appropriate density is obtained through high-pressure reaction copolymerization, thereby achieving the effect of difficult dissolution of the cured photoresist, easy dissolution of the uncured photoresist in the development stage, and quick dissolution of the cured photoresist in the stripping stage. That is, by compounding carboxylic acid-based fillers and phenolic fillers and controlling the molecular weight of the raw material within a specific range, the good alkali solubility of the photoresist product in the development and stripping processes is achieved through segmented copolymerization and crosslinking copolymerization processes.

[0086] Experimental Example 2

[0087] The alkali solubility of the photoresist prepared from Examples 6-10 and Comparative Examples 4-6 in the developing and stripping process was tested, and the related results are summarized in Table 4.

[0088] The test method refers to Experimental Example 1.

[0089] Table 4 Alkali solubility of photoresist prepared from Examples 6-10 and Comparative Examples 4-6 in the developing and stripping process

[0090]

[0091] As shown in the alkali solubility data of Table 4, the photoresist prepared from Examples 6-10 has similar properties to Examples 1-5, in the developing process, the uncured photoresist is completely soluble, and the cured photoresist is completely insoluble; under the stripping process conditions, the completely cured photoresist can also be quickly dissolved, and Examples 6-10 also have good alkali solubility in the developing and stripping process.

[0092] Comparative Example 4 does not surface functionalize the photoinitiator, and has high solubility in the developing process regardless of whether it is cured or not, resulting in a significant decrease in the performance of the product photoresist. Comparative Example 5 has a single addition of the photoinitiator, which significantly reduces the dispersibility, resulting in the aggregation of the dispersant during the curing process, which reduces the developing effect and also makes the photoresponse of the photoresist worse, so that the low alkaline environment cannot effectively distinguish between the cured and uncured photoresist, and it takes a longer time to completely dissolve in the stripping process. Comparative Example 6 has too low a crosslinking density due to the absence of TEMED, which has too high an alkali solubility in the developing process, and cannot guarantee that the cured photoresist will not be alkali soluble, and it takes a longer process to completely dissolve in the stripping process.

[0093] In summary, the functionalized TPO-L can effectively anchor the polymer chains, making the segment distance moderate, while maintaining a sensitive photo-initiated response, and making the cured photoresist have a moderate crosslinking density. Through the step-by-step premixing and crosslinking copolymerization process, the crosslinking density of the photoresist is further controlled, which synergistically improves the photoresponse efficiency of the photoresist product and ensures that it has good alkali solubility in the cured and uncured states.

[0094] Experimental Example 3

[0095] The viscosity and flowability of the photoresist prepared from Examples 11-15 and Comparative Examples 7-9 were tested, and the related results are summarized in Table 5.

[0096] The viscosity test method is as follows: the photoresist sample is placed in a constant temperature water bath, and the temperature is kept stable at 25°C, and the measurement is carried out using a rotary viscometer at 60 rpm, and the RV-1 rotor is selected. Record the viscosity (cP) data.

[0097] The test method for flowability is as follows: 0.1 mL of the photoresist sample is dropped on a silicon wafer placed at an angle of 30°, and the flow distance (cm) of the photoresist sample is recorded after the sample is allowed to flow naturally at 25°C for 60 s. The greater the flow distance, the better the flowability of the photoresist.

[0098] Table 6 Viscosity and flowability of photoresists prepared in Examples 11-15 and Comparative Examples 7-9

[0099]

[0100] As shown in the viscosity and flowability data in Table 6, the photoresists prepared in Examples 11-15 have moderate viscosity and flowability, and can be well coated and developed. In Comparative Example 7, the crosslinking density is reduced due to the reduced amount of CTAB, resulting in reduced viscosity and increased flowability. In Comparative Example 8, the viscosity of the product is increased and the flowability is poor because polyethylene glycol monomethyl ether is not added. In Comparative Example 9, the crosslinking density of the photoresist product is significantly reduced due to the reduced reaction temperature during the graft copolymerization, resulting in reduced viscosity and excessively high flowability.

[0101] In summary, by microemulsion polymerization of the carboxyl filler precursor and modification of the phenolic filler precursor with a coupling agent, and by graft copolymerization of the water-soluble precursor, the crosslinking density and interaction of the polymer chains in the photoresist are synergistically controlled, and a three-dimensional crosslinking network with moderate density is formed, so that the photoresist product has appropriate viscosity and flowability, and the balance between viscosity and flowability is achieved.

[0102] Experimental Example 4

[0103] The storage stability of the photoresists prepared in Examples 16-20 and Comparative Examples 10-11 is summarized in Table 7.

[0104] The test method for storage stability is as follows: the alkali solubility test and viscosity test in the stripping process are performed on the sample photoresist according to the test methods in Experimental Examples 1 and 3, and after the sample is stored at 60°C for 14 days, the alkali solubility test and viscosity test in the stripping process are repeated, and the results are recorded.

[0105] Table 7 Storage stability of photoresists prepared in Examples 16-20 and Comparative Examples 10-11

[0106]

[0107] As shown in the storage stability data of Table 7, the photoresists prepared in Examples 16-20 have good alkali solubility and moderate viscosity before storage test, and after storage test, the alkali solubility slightly decreases, but still has good performance, and the viscosity also decreases slightly, but does not greatly affect its performance. Comparative Example 10, due to only one stage of vacuum defoaming treatment, the viscosity slightly increases before storage test, and the alkali solubility significantly decreases after storage test, and the viscosity greatly increases. Comparative Example 11, due to the excessive addition of alkali-soluble fillers, the viscosity significantly increases, the viscosity increases more greatly after storage test, and the alkali solubility also significantly decreases.

[0108] In summary, the reasonable amount of alkali-soluble fillers added improves the alkali solubility of the photoresist product while ensuring that the key physical parameters such as the viscosity of the photoresist product are within a reasonable range, and in combination with two stages of vacuum defoaming treatment, effectively improves the purity and stability of the photoresist product under different application ratios, and after long-term storage, the alkali solubility can still be good, and the light response efficiency decay degree is low.

[0109] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A process for the preparation of a developer-removable alkali-soluble photoresist, characterized by: The preparation method is as follows: The carboxyl filler precursor is subjected to microemulsion polymerization to obtain a carboxyl filler; The carboxyl filler precursor comprises polyacrylate and polystyrene. The microemulsion polymerization process is as follows: the polyacrylate, the polystyrene and cetyltrimethylammonium bromide are dissolved in tetrahydrofuran, stirred at a rotation speed of 300-500 rpm for 30 min, then ammonium persulfate is added, and the reaction is carried out at a reaction temperature of 85 ℃ and a reaction pH of 5.5-6.5 for 4 h under nitrogen protection, and the carboxyl filler is obtained after cooling. The phenolic filler precursor is modified by a coupling agent to obtain a phenolic filler; The phenolic filler precursor is bisphenol A phenolic resin. The coupling agent modification process is as follows: 20 parts of the bisphenol A phenolic resin is dissolved in 100 parts of ethanol, 3 parts of KH550 is added, and stirring is carried out at 60 ℃ for 2 h, then the ethanol is removed by rotary evaporation, and vacuum drying is carried out at 80 ℃ for 2-4 h. The carboxyl filler and the phenolic filler are subjected to copolymerization treatment to obtain an alkali-soluble filler. The copolymerization treatment process is as follows: 58-63 parts of the carboxyl filler and 33-40 parts of the phenolic filler are dispersed in 200 parts of tetrahydrofuran, stirring is carried out at a rotation speed of 270-350 rpm, 0.45 parts of azobisisobutyronitrile is added, and the reaction is carried out at 120 ℃ and a reaction pressure of 1.5 MPa for 3 h, and the obtained product is washed with acetone and dried. A water-soluble precursor is subjected to graft copolymerization to obtain a water-soluble polymer monomer. 2,4,6-trimethylbenzoyl phenyl ethyl phosphonate is subjected to surface functionalization to obtain a modified photoinitiator. The modified photoinitiator and the water-soluble polymer monomer are premixed at 10-20 ℃ to obtain a pre-polymer monomer. 100 parts of the pre-polymer monomer and 45-115 parts of the alkali-soluble filler are uniformly dispersed, and crosslinking copolymerization is carried out to obtain a photoresist precursor. The photoresist precursor is subjected to vacuum degassing to obtain the alkali-soluble photoresist.

2. The method for preparing an alkali-soluble photoresist according to claim 1, characterized in that: The number average molecular weight of the polyacrylate is 3000-5000.

3. The method for preparing an alkali-soluble photoresist according to claim 1, characterized in that: The hydroxymethyl content of the bisphenol A phenolic resin is 42%.

4. The method of claim 1, wherein the method is characterized by: The water-soluble precursor comprises hydroxyethyl acrylate and ethoxy acrylate; the graft copolymerization process is as follows: the hydroxyethyl acrylate and the ethoxy acrylate are mixed uniformly, oxygen is removed by nitrogen purging, dichloromethane and polyethylene glycol monomethyl ether are added, EDTA and sodium persulfate are added at a temperature of 80 ℃, stirring is carried out at a rotation speed of 400-700 rpm for 5 h, and the water-soluble polymer monomer is obtained after removing the solvent by vacuum distillation.

5. The method of claim 1, wherein the method is characterized by: The surface functionalization process is as follows: 50 parts of the 2,4,6-trimethylbenzoyl phenyl ethyl phosphonate and 57-61 parts of methacryloyl chloride are dissolved in 100 parts of DMF, stirring is carried out at a rotation speed of 500 rpm at 50 ℃ for 8 h, the obtained product is precipitated in n-hexane, and vacuum drying is carried out to obtain the modified photoinitiator.

6. The method of claim 1, wherein the method further comprises: adding a base to the solution to form a basic solution; and adding a base to the solution to form a basic solution. The pre-mixed process is as follows: 1.5 parts of the modified photoinitiator is added into 100 parts of the water-soluble polymerization monomer at 10-20 ℃ in 3 times with an interval of 5 min, and the mixture is stirred at a speed of 200 rpm in the dark for 40 min to obtain a pre-polymerization monomer.

7. The method of claim 1, wherein the method further comprises: adding a base to the solution to form a basic solution; and adding a base to the solution to form a basic solution. The process of the reduced-pressure defoaming is as follows: the photoresist precursor is heated to 45 ℃ under an operating pressure of 0.2 atm, and then the operating pressure is reduced to 0.05-0.1 atm after 30 min of incubation; the photoresist precursor is treated at an ultrasonic frequency of 40 kHz for 15 min, filtered, and then packaged to obtain the alkali-soluble photoresist capable of being developed and removed by a photoresist.

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