Highly transparent photosensitizer and polyimide photoresist and polyimide film comprising the same

Abstract

The present application relates to the technical field of photosensitizer materials. More particularly, it relates to a high-transparency photosensitizer, a polyimide photoresist containing the same and a polyimide film. The structural general formula of the high-transparency photosensitizer is shown as formula I, wherein R represents one of an alkyl group with 1-10 carbon atoms or a cycloalkyl group with 3-10 carbon atoms; D represents H or a group shown as formula II, and at least one D represents a group shown as formula II. The high-transparency photosensitizer can effectively inhibit the yellowing reaction, significantly improve the optical transmittance of the cured glue layer, increase the transmittance at a wavelength of 400 nm from 80% to 90%, and maintain the original photoetching sensitivity and the residual film rate after curing, thereby achieving a good balance between optical performance and process performance.I; II

Description

Technical Field

[0001] This invention relates to the field of photosensitizer materials technology. More specifically, it relates to a highly transparent photosensitizer and a polyimide photoresist and a polyimide film containing the same. Background Technology

[0002] The photosensitive polyimide (PSPI) photoresist material, which is currently widely used in the planarization layer and pixel definition layer of display panels, generally has a low transmittance in the visible light area after thermal curing. It is also usually accompanied by the inherent pale yellow appearance of polyimide material, which is characterized by a high yellowness value.

[0003] With the continuous advancement of display technology, especially the promotion of new technologies such as under-display cameras, more stringent requirements have been placed on the transmittance and yellowness of display materials in the visible light band (400–780nm). Traditional PSPI photoresists are no longer sufficient to meet the demands of current high-end applications, necessitating the development of a PSPI photoresist with higher transmittance and lower yellowness in the visible light range to support the development of more advanced display technologies. Many factors contribute to the yellowing of PSPI photoresists after curing. One key reason is that the non-photosensitive portion of commonly used photosensitizers reacts with photosensitive resins, functional additives, and other components during the curing process, causing yellowing and thus reducing the transmittance of the cured film in the visible light band. Summary of the Invention

[0004] To address the aforementioned problems, the first objective of this invention is to provide a highly transparent photosensitizer. This invention proposes a novel photosensitizer structure that significantly improves the visible light transmittance at 400 nm after photoresist curing, while maintaining its original photolithographic sensitivity and residual film yield after curing, thereby achieving a good balance between optical and process performance.

[0005] The second objective of this invention is to provide a highly transparent polyimide photoresist.

[0006] A third objective of this invention is to provide a photosensitive polyimide film.

[0007] To achieve the first objective mentioned above, the present invention adopts the following technical solution: This invention discloses a highly transparent photosensitizer, the general structural formula of which is shown in Formula I: I; II; In this case, R represents one of the following: an alkyl group with 1-10 carbon atoms or a cycloalkyl group with 3-10 carbon atoms. D represents H or the group shown in Formula II, and at least one D represents the group shown in Formula II.

[0008] Furthermore, each occurrence of R represents one of an alkyl group having 1-4 carbon atoms or a cycloalkyl group having 3-8 carbon atoms; for example, each occurrence of R represents methyl, ethyl, tert-butyl, cyclopentane or cyclohexane, etc.; preferably, R represents tert-butyl or cyclohexyl.

[0009] Furthermore, D represents the group shown in Formula II.

[0010] Furthermore, in Formula I, the three R's represent the same group.

[0011] Furthermore, the highly transparent photosensitizer is selected from the following structures: , , , , , , , . To achieve the second objective mentioned above, the present invention adopts the following technical solution: This invention discloses a high-transparency polyimide photoresist, which, by weight, comprises... 90-100 parts of polyimide resin; 10-25 parts of photosensitizer composition; 15-25 parts of crosslinking agent; 0.05-2 parts adhesive; Leveling agent 0.05-3 parts; The photosensitizer composition includes at least two highly transparent photosensitizers as described above.

[0012] Furthermore, the solid content of the polyimide photoresist is 5-25%; for example, the solid content of the polyimide photoresist can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 24%, etc.

[0013] Furthermore, the photosensitizer composition is a mixture, and its effect in inhibiting the yellowing reaction is also affected by the composition of the photosensitizer composition. In one specific embodiment, the composition of the photosensitizer composition is limited according to the ratio of different groups. When the ratio of the number of groups of formula II to H is 1:1-5:1, the effect of inhibiting the yellowing reaction is significant. For example, the ratio of the number of groups of formula II to H can be 1:1, 2:1, 3:1, 4:1, 5:1, etc.

[0014] The high-temperature yellowing of the Formula II structure molecule originates from the thermal decomposition of the azide group and the conjugated reconstruction of the naphthoquinone ring. The steric hindrance effect is used to hinder the contact between the azide group and oxygen, while reducing the electron cloud density of the N atom, which significantly increases the thermal decomposition temperature of the Formula II structure molecule. The introduction of hydrophobic groups reduces the catalytic effect of water molecules on the azide bond by utilizing the hydrophobic effect, and can also reduce intermolecular forces, improve the dispersibility in the resin matrix, and the membrane still maintains a high permeability after high-temperature baking.

[0015] Furthermore, the composition of the photosensitizer composition can also be limited according to the preparation method. The following is an exemplary method for preparing the photosensitizer composition, including the following steps: Under a nitrogen atmosphere, compound I-1 and 1,2-naphthoquinone diazido-5-sulfonyl chloride were dissolved in an organic solvent. An organic solvent containing triethylamine was added dropwise at room temperature, and the temperature of the reaction system was controlled not to exceed 30°C during the dropwise addition. After the dropwise addition was completed, the mixture was stirred at room temperature for 1.5-2.5 hours, filtered, and dried to obtain the final product. The compound of formula I-1 is selected from the following structures: I-1; Each time R appears, it indicates one of the following: an alkyl group with 1-10 carbon atoms or a cycloalkyl group with 3-10 carbon atoms.

[0016] In the above-mentioned method for preparing photosensitizer compositions, changing the structure of compound I-1 mainly affects the selection of the R group in the structure of compound I, and adjusting the molar ratio of compound I-1 and 1,2-naphthoquinone diazido-5-sulfonyl chloride mainly affects the ratio of the number of groups of formula II to H in the photosensitizer composition.

[0017] Furthermore, the molar ratio of compound I-1 to 1,2-naphthoquinone diazido-5-sulfonyl chloride is 1:1.5-1:7; exemplaryly, the molar ratio of compound I-1 to 1,2-naphthoquinone diazido-5-sulfonyl chloride can be 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, etc.

[0018] Furthermore, the molar ratio of triethylamine to 1,2-naphthoquinone diazido-5-sulfonyl chloride is 1:1.

[0019] Furthermore, the organic solvent is selected from 1,4-dioxane and dioxane.

[0020] Furthermore, as the alkali-soluble resin in this invention, the polyimide resin can be selected from polymers containing imide groups, such as polyimide, polyimide precursors, polyamide-imide, polyamide-imide precursors, and polyisoimide, and their precursors, but is not limited to the above categories; one or more of these can be used in combination. To achieve the solubility of the exposed portion in the alkaline developer, the resin structure must contain acidic groups that can combine with alkaline compounds, such as hydroxyl, carboxyl, and sulfonic acid groups. The solubility is usually controlled by adjusting the content of acidic groups in the resin. Specific methods include introducing hydroxyl groups, adjusting the degree of imidization of the polyimide (to control the carboxyl content), or introducing ester groups.

[0021] Polyimide resins can be synthesized by known and universal methods. For example, by reacting tetracarboxylic dianhydride with a diamine compound at low temperature; or by reacting the two at low temperature followed by partial esterification with N,N-dimethylformamide methyl acetal in an N-methylpyrrolidone solvent; or by reacting tetracarboxylic dianhydride with an alcohol to generate a diester, which is then reacted with a diamine in the presence of a condensing agent; or by reacting tetracarboxylic dianhydride with an alcohol to obtain a diester, followed by acyl chloride of the residual carboxyl group, and then reacting with a diamine.

[0022] Examples of acid dianhydrides used as polyimides, polyimide precursors, and copolymers include cyclohexanetetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,3,3',4'-biphenyltetracarboxylic acid dianhydride, pyromellitic acid dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride, 2,2',3,3'-benzophenone tetracarboxylic acid dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, and bis(3,4-dicarboxyphenyl)propane dianhydride. The dianhydride can be one or more of the following: aromatic tetracarboxylic acid dianhydrides such as alkyl dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorenic acid dianhydride, 9,9-bis{4-(3,4-dicarboxyphenoxy)phenyl}fluorenic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 2,3,5,6-pyridinetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride; and aliphatic tetracarboxylic acid dianhydrides such as butanetetracarboxylic acid dianhydride and 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride. Two or more of the above-mentioned dianhydrides may also be used.

[0023] Specific examples of diamine compounds include 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, benzidine, m-phenylenediamine, p-phenylenediamine, 1,5-naphthylenediamine, 2,6-naphthylenediamine, bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl] ether, 1,4-bis(4-aminophenoxy)benzene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2 Compounds such as 2'-diethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-diethyl-4,4'-diaminobiphenyl, 2,2',3,3'-tetramethyl-4,4'-diaminobiphenyl, 3,3',4,4'-tetramethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 9,9-bis(4-aminophenyl)fluorene, or compounds obtained by substituting at least some of the hydrogen atoms in their aromatic rings with alkyl and / or halogen atoms. Two or more of the above diamines may also be used.

[0024] Furthermore, the crosslinking agent in this invention is a thermally crosslinking compound, referring to a compound having at least two thermally reactive functional groups within its molecule, represented by alkoxymethyl, benzoxazine, or epoxy groups. The crosslinking agent can crosslink resins or other additives, improving the heat resistance, chemical resistance, and hardness of the thermocured film. Preferably, compounds with a benzoxazine structure are preferred because they undergo crosslinking reactions based on ring-opening addition reactions, thus avoiding degassing during curing and exhibiting minimal heat-induced shrinkage, thereby suppressing warping.

[0025] Preferred examples of compounds having a benzoxazine structure include Ba-type benzoxazine, Bm-type benzoxazine (the above are trade names manufactured by Shikoku Chemical Industry), benzoxazine adducts of polyhydroxystyrene resin, and linear phenolic dihydrobenzoxazine compounds. They can be used alone or in combination of two or more.

[0026] Preferred examples of crosslinking agents for compounds having at least two epoxy groups include, for example, Epolight 40E, Epolight 100E, Epolight 200E, Epolight 400E, Epolight 70P, Epolight 200P, Epolight 400P, Epolight 1500NP, Epolight 80MF, Epolight 4000, Epolight 3002 (all manufactured by Kyoeisha Chemical Co., Ltd.), Denacol EX-212L, Denacol EX-214L, Denacol EX-216L, Denacol EX-850L (all manufactured by Nagase ChemteX Co., Ltd.), GAN, GOT (all manufactured by Nippon Kayaku Co., Ltd.), Epikote 828, Epikote 1002, Epikote 1750, Epikote... 1007, YX8100-BH30, E1256, E4250, E4275 (all manufactured by Japan Epoxy Resins Co., Ltd.), EPICLON EXA-9583, HP4032 (all manufactured by Dai Nippon Ink Chemical Industry Co., Ltd.), VG3101 (manufactured by Mitsui Chemicals Co., Ltd.), TEPIC S, TEPIC G, TEPIC P (all manufactured by Nissan Chemical Industry Co., Ltd.), Denacol EX-321L (manufactured by Nagase ChemteX Co., Ltd.), NC6000 (manufactured by Nippon Kayaku Co., Ltd.), EPOTOHTOYH-434L (manufactured by Toto Kasei Co., Ltd.), EPPN502H, NC3000 (manufactured by Nippon Kayaku Co., Ltd.), EPICLON N695, HP7200 (all manufactured by Dai Nippon Ink Chemical Industry Co., Ltd.), etc. These can be used individually or in combination of two or more.

[0027] Preferred examples of compounds having an alkoxymethyl group include, for example, DML-PC, DML-PEP, DML-OC, DML-OEP, DML-34X, DML-PTBP, DML-PCHP, DML-OCHP, DML-PFP, DML-PSBP, DML-POP, DML-MBOC, DML-MBPC, DML-MTrisPC, DML-BisOC-Z, DML-BisOCHP-Z, DML-BPC, DML-BisOC-P, DMOM-PC, DMOM-PTBP, and DMOM-M. BPC, TriML-P, TriML-35XL, TML-HQ, TML-BP, TML-pp-BPF, TML-BPE, ML-BPA, TML-BPAF, TML-BPAP, TMOM-BP, TMOM-BPE, TMOM-BPA, TMOM-BPAF, TMOM-BPAP, HML-TPPHBA, HML-TPHAP, HMOM-TPPHBA, HMOM-TPHAP (all trade names, manufactured by Honshu Chemical Industry), NIKALAC (registered trademark) MX-290, NIKALAC MX-280, NIKALAC MX-270, NIKALAC MX-279, NIKALAC MW-100LM, NIKALAC MX-750LM (all trade names, manufactured by Sanwa Chemical). These can be used alone or in combination of two or more.

[0028] Furthermore, in order to improve the wettability of the photoresist on the substrate, improve the smoothness of the photoresist film surface, and suppress the generation of film defects, a certain amount of leveling agent needs to be added to the formulation. The type of leveling agent can be selected from acrylic, organosilicon, or fluorocarbon compounds, such as the SH series, SD series, and ST series of Dow Corning Toray Co., Ltd., the BYK series of BYK Japan KK, the KP series of Shin-Etsu Chemical Co., Ltd., the disk Home series of Nippon Yushi Co., Ltd., and the TSF series of Toshiba Silicones Ltd., etc.

[0029] Furthermore, in order to improve the adhesion between the photoresist film and the substrate and prevent warping or peeling of the film under high temperature and high humidity conditions, a certain amount of adhesive needs to be added to the formulation, preferably 0.02-3 parts. The type of adhesive is preferably a siloxane, such as: γ-glycidoxypropyltrimethoxysilane (KH560), γ-aminopropyltriethoxysilane (KH550), γ-aminopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, p-aminophenyltrimethoxysilane, 3-(m-aminophenoxy)trimethoxysilane, 3-mercaptomethyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, etc.

[0030] Furthermore, as needed, compounds with phenolic hydroxyl groups may be included, within a range that does not reduce the shrinkage rate of the cured film. The inclusion of these compounds allows for adjustment of the development time and improvement of scum formation. Examples of compounds with phenolic hydroxyl groups include, for instance, Bis-Z, BisP-EZ, TekP-4HBPA, TrisP-HAP, TrisP-PA, BisOCHP-Z, BisP-MZ, BisP-PZ, BisP-IPZ, BisOCP-IPZ, BisP-CP, BisRS-2P, BisRS-3P, BisP-OCHP, Methylenetris-FR-CR, BisRS-26X (all trade names, manufactured by Honshu Chemical Industry Co., Ltd.), BIP-PC, BIR-PC, BIR-PTBP, BIR-BIPC-F (all trade names, manufactured by Asahi Organic Materials Co., Ltd.), phenolic varnish resins, etc., and more than two of the aforementioned compounds may be included.

[0031] To achieve the third objective mentioned above, the present invention adopts the following technical solution: This invention discloses a photosensitive polyimide film, which is obtained by dissolving the polyimide photoresist as described above, coating it onto a substrate, and then curing it.

[0032] The beneficial effects of this invention are as follows: This invention provides a highly transparent photosensitizer and a polyimide photoresist and a polyimide film containing the same. This highly transparent photosensitizer effectively inhibits the aforementioned yellowing reaction, significantly improves the optical transmittance of the cured adhesive layer, increasing the transmittance at a wavelength of 400 nm from 80% to 90%, while maintaining excellent photolithographic performance despite a significant reduction in yellowness. Attached Figure Description

[0033] Figure 1 This is the liquid phase spectrum of the photosensitizer composition P1. Detailed Implementation

[0034] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0035] Photosensitizer composition P1 II or H; The reaction vessel was purged with nitrogen beforehand. 27.24 g (0.05 mol) of 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane (CAS: 1843-03-4) and 81.2 g (0.30 mol) of 1,2-naphthoquinone diazide-5-sulfonyl chloride (CAS: 3770-97-6) were dissolved in 450 ml of dioxane and allowed to return to room temperature. Then, a mixed solution of 30.36 g (0.30 mol) of triethylamine in 100 ml of dioxane was slowly added dropwise, with the temperature controlled below 30°C. After the addition was complete, the solution was kept at 30°C for 2 hours. The triethylamine salt was filtered, and the filtrate was added to water and washed three times each with dilute hydrochloric acid and deionized water. The precipitate was then collected by filtration. Finally, the precipitate was dried using a vacuum dryer to obtain the photosensitizer composition P1.

[0036] The prepared photosensitizer composition was subjected to liquid phase testing. The testing conditions and equipment information are as follows: Equipment: Agilent 1290 Infinity II high performance liquid chromatograph.

[0037] Chromatographic column: Discovery C18 250mm*4.6mm, 5μm.

[0038] Wavelength: 206nm.

[0039] Mobile phase: Acetonitrile: Water = 1:1 (15 min).

[0040] Injection volume: 9 μL.

[0041] Flow rate: 1.0 ml / min.

[0042] Figure 1 The liquid phase spectrum of photosensitizer composition P1 is shown. Testing revealed that the photosensitizer composition contains one monosubstituted product selected from formula II, two disubstituted products selected from formula II, and three trisubstituted products selected from formula II, with their specific proportions shown in Table 1. Ultimately, the ratio of formula II groups to H groups in the photosensitizer composition was determined to be approximately 4:1.

[0043] Table 1

[0044] Photosensitizer composition P2 II or H; The reaction vessel was purged with nitrogen beforehand. 31.15 g (0.05 mol) of 4,4',4''-(1-methylpropyl-1-yl-3-ylidene)tris(2-cyclohexyl-5-methylphenol) (CAS: 111850-25-0) and 94.00 g (0.35 mol) of 1,2-naphthoquinone diazido-5-sulfonyl chloride (CAS: 3770-97-6) were dissolved in 1200 ml of dioxane and allowed to return to room temperature. Then, a mixed solution of dioxane (120 ml) containing 35.42 g (0.35 mol) triethylamine was slowly added dropwise, maintaining the temperature below 30°C. After the addition was complete, the solution was kept at 30°C for 2 hours. The triethylamine salt was filtered, and the filtrate was added to water and washed three times each with dilute hydrochloric acid and deionized water. The precipitate was then collected by filtration. Finally, the precipitate was dried using a vacuum dryer to obtain the photosensitizer composition P2. Following the aforementioned testing method, the ratio of Formula II groups to H in the photosensitizer composition was ultimately determined to be approximately 5:1.

[0045] Comparison photosensitizer composition P3 TPPA-PAC (purchased from Toyo Kasei Corporation, Japan, CAS No.: 137902-98-8) has the following general formula structure, wherein in this comparative composition, D represents formula II group or H, and the ratio of formula II group to H is 5:1.

[0046] II or H.

[0047] Resin R1 Under a dry nitrogen stream, 9 mmol of the diamine monomer 2,2-bis(4-aminophenyl)hexafluoropropane (6FAP) was added to a three-necked flask, followed by the sequential addition of 150 mL of N-methylpyrrolidone (NMP). After the 6FAP was completely dissolved, 10 mmol of 4,4'-oxophthalic anhydride (ODPA) was added. The mixture was stirred at room temperature for 2 h, followed by the addition of 2 mmol of m-aminophenol (MAP). Stirring was continued for 30 min to obtain a viscous reaction solution. Then, 18 mmol of N,N-dimethylformamide diethyl acetal (DMF-DEA) diluted in 50 mL was slowly added dropwise. The mixture was stirred at 40 °C for 4 h. After stirring, the solution was cooled to room temperature, and the reaction solution was slowly poured into 5 L of rapidly stirred deionized water to obtain a white precipitate. The precipitate was collected by filtration, washed three times with water, and dried at 60 °C for 72 h to obtain polyamic acid ester (R1) resin with a molecular weight of 2000-200000.

[0048] Resin R2 The synthesis route of resin R2 is the same as that of resin R1. The difference is that 4,4'-oxydiphthalic anhydride (ODPA) in the preparation of resin R1 is replaced with pyromellitic dianhydride (PMDA). The molecular weight of the resulting resin R2 is 2000-200000.

[0049] Resin R3 The synthesis route of resin R3 is the same as that of resin R1. The difference is that 2,2-bis(4-aminophenyl)hexafluoropropane (6FAP) in the preparation of resin R1 is replaced with diaminodiphenyl ether (ODA), and the molecular weight of the resulting resin R3 is 2000-200000.

[0050] Photoresist Examples 1-9 This example provides a method for preparing photoresist. The material feeding details for each embodiment are shown in Table 2. The specific preparation steps are as follows: This example provides a method for preparing polyimide photoresist. The material feeding details for each embodiment are shown in Table 2. The specific preparation steps are as follows: Under N2 protection, the amount of resin formulated according to Table 2 was added to 1200 parts by weight of a mixed solution of propylene glycol methyl ether (PGME), ethyl lactate (EL), and γ-butyrolactone (GBL) (the mass ratio of PGME, EL, and GBL was 7:2:1). Then, the photosensitizer composition, crosslinking agent, leveling agent, and adhesive were added in sequence and stirred until completely dissolved and clear. After the overall solution turned rose red, stirring was stopped, and the sample was placed in a light-proof, clean packaging bottle and stored at low temperature.

[0051] Table 2

[0052] Note: The CAS number of compound CL1 is 161679-94-3, the CAS number of compound CL2 is 672926-26-0, the CAS number of compound CL3 is 53091-58-0, the CAS number of compound SL1 is BYK333, the CAS number of compound SL2 is BYK345, the CAS number of compound SL3 is BYK370, the CAS number of compound H1 is KH550, the CAS number of compound H2 is KH560, the CAS number of compound H3 is KH570, and the number of parts is the mass parts.

[0053] Comparative Example This example provides a method for preparing photoresist. The material feeding details for each comparative example are shown in Table 3. The specific preparation steps are the same as those in Examples 1-9.

[0054] Table 3

[0055] Note: The CAS number of compound CL1 is 161679-94-3, the CAS number of compound CL2 is 672926-26-0, the CAS number of compound CL3 is 53091-58-0, the CAS number of compound SL1 is BYK333, the CAS number of compound SL2 is BYK345, the CAS number of compound SL3 is BYK370, the CAS number of compound H1 is KH550, the CAS number of compound H2 is KH560, the CAS number of compound H3 is KH570, and the CAS number of compound P3 is TPPA-PAC (CAS number: 137902-98-8). The number of parts is the mass parts.

[0056] Performance testing The photoresists prepared in Examples 1-9 and Comparative Examples 1-9 were tested as follows, and the test conditions for the prepared photoresists were as follows: 1) Imaging capability evaluation: The photoresists obtained in Examples 1-9 and Comparative Examples 1-9 were applied to glass substrates using an ACT-8 coating and developing apparatus (manufactured by Tokyo Electron Limited) via spin coating. After drying, the coatings were obtained. Next, the coatings were exposed to light using an i-line stepper under the cover of a photomask, followed by development in 2.38 wt% tetramethylammonium hydroxide (TMAH) for 60 s, and then rinsed with pure water. The etched lines or trenches were inspected using a scanning electron microscope (SEM). The following criteria were considered excellent: lines or trenches with a width less than 3 μm were clearly etched without bending or defects; lines or trenches with a width between 3 and 10 μm were clearly etched without bending or defects; and lines or trenches with a width greater than 10 μm were clearly etched without bending or defects.

[0057] 2) Sensitivity assessment: Using an ACT-8 coating apparatus (manufactured by Tokyo Electron Limited), the photoresists obtained in Examples 1-9 and Comparative Examples 1-9 were coated onto glass substrates using a spin coating method, and pre-baked at 120°C for 2 min. The coatings were then exposed using an i-line stepper exposure machine. Subsequently, a 2.38 wt% tetramethylammonium hydroxide (TMAH) aqueous solution was sprayed onto the substrate using an automatic developing apparatus for 60 s, followed by rinsing with pure water, and finally the surface moisture of the coating was dried by spin drying. The minimum necessary exposure for complete dissolution of the photosensitive components was used as the sensitivity.

[0058] 3) Evaluation of residual film rate: Using an ACT-8 coating apparatus (manufactured by Tokyo Electron Limited), the photoresists obtained in Examples 1-9 and Comparative Examples 1-9 were coated onto a glass substrate using a spin coating method. The substrate was pre-baked at 120°C for 2 minutes, resulting in a film thickness of d1. The film was then exposed using an i-line stepper, sprayed with a 2.38 wt% tetramethylammonium hydroxide (TMAH) aqueous solution for 60 seconds using an automatic developing apparatus, and subsequently heat-treated to obtain a cured film with a thickness of d2. The residual film yield was calculated as (d2 / d1)*100%.

[0059] 4) Transmission rate evaluation: Using an ACT-8 coating apparatus (manufactured by Tokyo Electron Limited), the photoresists obtained in Examples 1-9 and Comparative Examples 1-9 were coated onto a glass substrate using a spin coating method. The substrate was pre-baked at 120°C for 2 minutes, resulting in a film thickness of d1. The corresponding films were then exposed, developed, and heat-treated to obtain cured films. The wavelengths of the cured films from 300 to 800 nm were measured and evaluated using a spectrophotometer (Hitachi, Ltd.'s "Dual-Beam Spectrophotometer U-2900"). The transmittance at 400 nm was used as the criterion for evaluating visible light transmittance.

[0060] 5) Yellowness value measurement: The polyimide photoresist was coated onto a glass substrate using an ACT-8 coating and developing apparatus (manufactured by Tokyo Electron Limited) via spin coating. The substrate was pre-baked at 120°C for 2 minutes. The yellowness value of the resulting film was determined according to the Yellowness Index ASTM E313-2015 test standard. The yellowness value testing equipment was a CM-36dG spectrometer from KONICAMINILTA.

[0061] The test results are shown in Table 4.

[0062] Table 4

[0063] The results in Table 4 show that the photoresist prepared by this invention contains a self-developed photosensitizer composition, which can significantly improve the yellowing problem of the film. Its improvement effect is better than that of the comparative example containing TPPA-PAC (CAS No.: 137902-98-8). It was also found that the photoresist can maintain its photolithographic sensitivity and residual film rate while improving transmittance.

[0064] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A highly transparent photosensitizer, characterized in that, The general structural formula of the highly transparent photosensitizer is shown in Formula I: I； Ⅱ； In this case, R represents one of the following: an alkyl group with 1-10 carbon atoms or a cycloalkyl group with 3-10 carbon atoms. D represents H or the group shown in Formula II, and at least one D represents the group shown in Formula II.

2. The highly transparent photosensitizer according to claim 1, characterized in that, R represents tert-butyl or cyclohexyl.

3. The highly transparent photosensitizer according to claim 1, characterized in that, The D represents the group shown in Formula II.

4. The highly transparent photosensitizer according to claim 1, characterized in that, The highly transparent photosensitizer is selected from the following structures: 、 、 、 、 、 、 、 。 5. A highly transparent polyimide photoresist, characterized in that, The high-transparency polyimide photoresist comprises, by weight parts 90-100 parts of polyimide resin; 10-25 parts of photosensitizer composition; 15-25 parts of crosslinking agent; 0.05-2 parts adhesive; Leveling agent 0.05-3 parts; The photosensitizer composition comprises at least two highly transparent photosensitizers as described in any one of claims 1-4.

6. The polyimide photoresist according to claim 5, characterized in that, In the photosensitizer composition, the ratio of Formula II groups to H is 1:1 to 5:

1.

7. The polyimide photoresist according to claim 5, characterized in that, The photosensitizer composition was prepared according to the following steps: Under a nitrogen atmosphere, compound I-1 and 1,2-naphthoquinone diazido-5-sulfonyl chloride were dissolved in an organic solvent. An organic solvent containing triethylamine was added dropwise at room temperature, and the temperature of the reaction system was controlled not to exceed 30°C during the dropwise addition. After the dropwise addition was completed, the mixture was stirred at room temperature for 1.5-2.5 hours, filtered, and dried to obtain the final product. The compound of formula I-1 is selected from the following structures: I-1； Each time R appears, it indicates one of the following: an alkyl group with 1-10 carbon atoms or a cycloalkyl group with 3-10 carbon atoms.

8. The polyimide photoresist according to claim 7, characterized in that, The molar ratio of compound I-1 and 1,2-naphthoquinone diazido-5-sulfonyl chloride is 1:1.5-1:7; The molar ratio of triethylamine to 1,2-naphthoquinone diazido-5-sulfonyl chloride is 1:

1.

9. The polyimide photoresist according to claim 5, characterized in that, The polyimide resin is selected from one or more of polyimide, polyimide precursor, polyamide imide, polyamide imide precursor, and polyether imide; The crosslinking agent is selected from one or more of compounds having a benzoxazine structure, compounds having at least two epoxy structures, and compounds having an alkoxymethyl group; The leveling agent is selected from one or more of acrylic leveling agents, silicone leveling agents, and fluorocarbon leveling agents; The adhesive is selected from one or more of γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, p-aminophenyltrimethoxysilane, 3-(m-aminophenoxy)trimethoxysilane, 3-mercaptomethyltrimethoxysilane, and 3-mercaptopropyltriethoxysilane.

10. A photosensitive polyimide film, characterized in that, The photosensitive polyimide film is obtained by dissolving the polyimide photoresist according to any one of claims 5-10, coating it onto a substrate, and then curing it.

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