A thick film positive photoresist composition, its preparation method and use

Abstract

The application provides a thick film positive photoresist composition, a preparation method and application thereof. The thick film positive photoresist composition comprises 70-90 parts of a base resin, 10-30 parts of a photosensitive compound and 100-150 parts of a solvent A; the base resin comprises a benzophenone modified phenolic resin and optionally an unmodified phenolic resin; the mass percentage of benzophenone groups in the base resin is 0.8-7.5% based on 100% of the mass percentage of the base resin; the photosensitive compound comprises a non-benzophenone photosensitive compound and optionally a benzophenone compound; the mass percentage of the benzophenone compound is less than or equal to 3.0% based on 100% of the mass percentage of the photosensitive compound. The application improves the uniformity of the benzophenone structure in the thick film positive photoresist composition by designing the specific composition of the thick film positive photoresist composition, thereby improving the steepness of the photoresist and realizing the development of the pattern.

Description

Technical Field

[0001] This invention belongs to the field of thick film photoresist technology, specifically relating to a thick film positive photoresist composition, its preparation method, and its application. Background Technology

[0002] In advanced interconnect technologies, photoresist layers are needed for current transmission in wafer-level chip-scale packaging, including solder bumps, gold bumps, copper pillars, and copper wires. These layers are then electroplated to form the final metal structure. Thick-film photoresist is a crucial material in these packaging processes. For example, solder bumps typically have a pitch of only 150 μm, requiring a photoresist thickness of 50 to 100 μm. Gold bumps, mainly used in TAB and COG technologies, have a pitch as low as 40 μm, sometimes as low as 10 μm. However, the precision and sidewall angle of the photoresist layer are critical, as the shape of the photoresist layer determines the final shape of the metal bumps.

[0003] CN114667486A discloses a positive chemically amplified photoresist composition and its method of use that does not contain a photoacid-generating agent (PAG). The composition comprises a phenolic resin component, a photosensitizer (PAC) component, and a solvent component, and does not include or require the use of added photoacid-generating agent (PAG). The PAC is free PAC, coupled PAC (PACb), or a combination thereof, including substituted or unsubstituted 2,1,5-DNQ materials or compounds thereof with substituted or unsubstituted 2,1,5-DNQ materials attached thereto, which do not form sulfonic acid upon UV exposure. This composition can be used in the fabrication of thick-film (3-10 μm) or thin-film (1-3 μm) photoresist devices. In thick-film applications, the morphology of the photoresist slices is addressed by changing the PAC content and the structure of the phenolic resin, thereby solving the T-topping problem. It has advantages such as low cost, high resolution, and strong process adaptability. CN117784524A discloses a thick-film positive photoresist, a photoresist layer, and a method for preparing the same. The thick-film positive photoresist, by weight, comprises: 30-70 parts of phenolic resin, 20-40 parts of a silicon-containing copolymer film-forming resin, 10-20 parts of a photosensitive compound, 0.01-1 part of a leveling agent, and 80-150 parts of a solvent. This technical solution, by adding a silicon-containing copolymer film-forming resin, solves the problems of film cracking, pattern deformation, and insufficient sidewall perpendicularity that are common in traditional thick-film photoresists in thick-film applications. It also improves the photoresist's adhesion, thermal stability, mechanical strength, and chemical resistance, enabling it to maintain good performance in thick-film photolithography processes such as wafer-level chip-scale packaging and meeting the requirements for high-precision pattern forming.

[0004] With advancements in existing technology, the developability, etching resistance, and steepness of thick-film photoresists have been continuously improved. Therefore, providing a novel thick-film photoresist composition to meet market demands has become an urgent technical problem to be solved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a thick-film positive photoresist composition, its preparation method, and its applications. The present invention designs the specific composition of the thick-film positive photoresist composition and further improves the uniformity of the distribution of the benzophenone structure in the thick-film positive photoresist composition by using benzophenone-modified phenolic resin. Simultaneously, through the combination with other components, it improves the steepness, resolution, and etching resistance of the photoresist layer, while also enhancing the development effect of the photoresist layer pattern.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a thick-film positive photoresist composition, the thick-film positive photoresist composition comprising 70-90 parts of a matrix resin, 10-30 parts of a photosensitive compound, and 100-150 parts of solvent A; the matrix resin comprising benzophenone-modified phenolic resin, optionally unmodified phenolic resin; the mass percentage of benzophenone groups in the matrix resin is 0.8-7.5% based on 100% mass content of the matrix resin; the photosensitive compound comprising a non-benzophenone photosensitive compound, optionally a benzophenone compound, the mass percentage of the benzophenone compound being ≤3.0% based on 100% mass content of the photosensitive compound.

[0007] The use of small-molecule benzophenone compounds (i.e., free benzophenone) in thick-film positive photoresist compositions can absorb ultraviolet light and reduce substrate reflection. However, free benzophenone is prone to aggregation, affecting precision and deteriorating the steepness of the photoresist layer and the development pattern effect. This invention introduces benzophenone-modified phenolic resin into the thick-film positive photoresist composition. The benzophenone groups (… (The dashed line indicates the connection site) is grafted into the phenolic resin molecular chain, which not only retains the light absorption advantage of benzophenone, but also achieves molecular-level uniform dispersion of benzophenone groups in the thick film positive photoresist composition. This solves the problem of easy aggregation of free benzophenone compounds, so that the thick film positive photoresist composition obtained by this composition has good sidewall verticality and good etching resistance, as well as good development pattern effect.

[0008] In this invention, benzophenone-modified phenolic resin can be used alone as the matrix resin, or a combination of benzophenone-modified phenolic resin and unmodified phenolic resin can be used as the matrix resin, as long as the mass content of benzophenone groups in the matrix resin is 0.8-7.5%. If the mass content of benzophenone groups in the matrix resin is too small, it will result in high substrate reflectance of the thick-film positive photoresist, further leading to Top loss phenomenon (the phenomenon of narrowing of the pattern size of the surface photoresist layer) in the photoresist layer morphology. If the mass content of benzophenone groups in the matrix resin is too high, it will result in Footing phenomenon in the photoresist layer morphology prepared by the thick-film positive photoresist composition (i.e., insufficient exposure at the bottom of the photoresist layer, resulting in obvious photoresist composition residue at the bottom after development, ultimately leading to an increase in the width of the bottom of the photoresist layer).

[0009] In this invention, the mass percentage of benzophenone groups in the matrix resin is calculated as M1 ÷ M2 × 100%; where M1 represents the amount of benzophenone used in the preparation of the modified phenolic resin. The mass of the benzophenone group in M2 represents the mass of the phenolic resin used in the preparation of benzophenone-modified phenolic resin. The sum of the mass of the matrix resin and the mass of the unmodified phenolic resin in the matrix resin.

[0010] In this invention, a high-performance thick-film positive photoresist composition was prepared by designing the photosensitive compound as a non-benzophenone-based photosensitive compound, thereby obtaining a high-performance photoresist layer. Alternatively, this invention designs the photosensitive compound as a combination of a non-benzophenone-based photosensitive compound and a benzophenone compound, and controls the mass percentage of the benzophenone compound in the photosensitive compound to ≤3.0%, thus preparing a high-performance thick-film positive photoresist composition, thereby obtaining a high-performance photoresist layer. If the mass percentage of the benzophenone compound in the photosensitive compound is too high, i.e., too much benzophenone compound is used, the agglomeration of the benzophenone compound in the thick-film positive photoresist composition will affect its precision, resulting in a deterioration in the steepness of the photoresist layer and the development pattern effect.

[0011] In this invention, a high-performance thick-film positive photoresist composition is prepared by combining a specific matrix resin and a specific photosensitive compound, and by controlling the amount of both within a specific range, thereby obtaining a photoresist layer with excellent overall performance.

[0012] In this invention, the base resin in the thick film positive photoresist composition is 70 parts, 72 parts, 74 parts, 76 parts, 78 parts, 80 parts, 82 parts, 84 parts, 86 parts, 88 parts, or 90 parts by weight.

[0013] The photosensitive compound in the thick film positive photoresist composition is in the form of 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, or 30 parts by weight.

[0014] The solvent A in the thick film positive photoresist composition is 100 parts, 105 parts, 110 parts, 115 parts, 120 parts, 125 parts, 130 parts, 135 parts, 140 parts, 145 parts, or 150 parts by weight.

[0015] Based on the mass percentage of the matrix resin being 100%, the content of benzophenone groups in the matrix resin is 0.8-7.5%, for example, it can be 0.8%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7.0% or 7.5%, etc.

[0016] Based on the mass percentage of the photosensitive compound being 100%, the mass percentage of the benzophenone compound is ≤3.0%, for example, it can be 0%, 0.2%, 0.5%, 0.7%, 1.0%, 1.2%, 1.5%, 1.8%, 2.0%, 2.3%, 2.5%, 2.7%, or 3.0%, etc.

[0017] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0018] Preferably, based on the mass percentage content of the matrix resin being 100%, the mass percentage content of the benzophenone group in the matrix resin is 1.0-5.0%, for example, it can be 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, or 5.0%, etc.

[0019] The present invention further designs the benzophenone group in the matrix resin to have a mass content of 1.0-5.0%, which further improves the overall performance of the thick film positive photoresist composition and the photoresist layer prepared therefrom.

[0020] Preferably, the matrix resin is benzophenone-modified phenolic resin.

[0021] Preferably, the raw materials for preparing the benzophenone-modified phenolic resin include phenolic resin and... .

[0022] Preferably, the phenolic resin and The mass ratio is (10-100):1, for example, it can be 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1 or 100:1, etc.

[0023] Preferably, the weight-average molecular weight of the phenolic resin is 300-90000 g / mol, for example, it can be 300 g / mol, 500 g / mol, 1000 g / mol, 2000 g / mol, 5000 g / mol, 8000 g / mol, 10000 g / mol, 20000 g / mol, 30000 g / mol, 40000 g / mol, 50000 g / mol, 60000 g / mol, 70000 g / mol, 80000 g / mol, or 90000 g / mol.

[0024] Preferably, the molecular weight distribution (PDI) of the phenolic resin is ≤2.5, for example, it can be 1.2, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4 or 2.5, etc.

[0025] Preferably, the benzophenone-modified phenolic resin is prepared by the following method, which includes the following steps: mixing phenolic resin and solvent B, and then adding... The reaction yields the benzophenone-modified phenolic resin.

[0026] It should be noted that the phenolic resin used to prepare benzophenone-modified phenolic resin can be a commercially available product or a homemade product. If it is a homemade product, this invention does not impose any special restrictions on the method for synthesizing the phenolic resin, and commonly used synthesis methods in the art are applicable.

[0027] Preferably, solvent B comprises any one or a combination of at least two of N,N-dimethylformamide (DMF), propylene glycol methyl ether, propylene glycol methyl ether acetate, ethylene glycol monomethyl ether acetate, butyl acetate, methyl isobutyl ketone, γ-butyrolactone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, dimethylformamide, toluene, or isopropanol. Preferably, the reaction is carried out in a protective atmosphere, the protective atmosphere including nitrogen.

[0028] Preferably, the reaction temperature is 65-85℃ (e.g., it can be 65℃, 66℃, 68℃, 70℃, 72℃, 74℃, 76℃, 78℃, 80℃, 82℃, 84℃ or 85℃, etc.), and the time is 16-20 h (e.g., it can be 16 h, 16.5 h, 17 h, 17.5 h, 18 h, 18.5 h, 19 h, 19.5 h or 20 h, etc.).

[0029] Preferably, the reaction further includes a post-processing step, the post-processing method including cooling, filtration, washing, concentration, and recrystallization.

[0030] Preferably, the weight-average molecular weight of the unmodified phenolic resin is 300-90000 g / mol, for example, it can be 300 g / mol, 500 g / mol, 1000 g / mol, 2000 g / mol, 5000 g / mol, 8000 g / mol, 10000 g / mol, 20000 g / mol, 30000 g / mol, 40000 g / mol, 50000 g / mol, 60000 g / mol, 70000 g / mol, 80000 g / mol, or 90000 g / mol, etc.

[0031] It should be noted that the present invention does not impose any special restrictions on the specific type of phenolic resin used to prepare benzophenone-modified phenolic resin, or the unmodified phenolic resin used as the matrix resin; commonly used phenolic resins in the art are applicable.

[0032] Preferably, the non-benzophenone photosensitive compound includes resin-type non-benzophenone photosensitive compounds.

[0033] In this invention, there are no special restrictions on the specific selection of resin-type non-benzophenone photosensitive compounds. Commonly used resin-type non-benzophenone photosensitive compounds in the art are applicable, including but not limited to: non-benzophenone photosensitive compounds with the brand name PE-20 or PA-15 purchased from Kisco-Daito.

[0034] Preferably, solvent A is selected from any one or a combination of at least two of propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether, propylene glycol methyl ether acetate, ethylene glycol monomethyl ether acetate, butyl acetate, methyl isobutyl ketone, γ-butyrolactone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, dimethylformamide, toluene, or isopropanol.

[0035] Preferably, the thick-film positive photoresist composition further includes 0.1-3 parts by weight of an additive (e.g., 0.1, 0.2, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, or 3 parts, etc.).

[0036] Preferably, the additives include any one or a combination of at least two of the following: leveling agents, sensitizers, plasticizers and crack-resistant agents, and crosslinking agents.

[0037] It should be noted that the present invention does not impose any special restrictions on the specific selection of the above-mentioned additives, and all commonly used additives in the art are applicable. For example, the leveling agents include, but are not limited to, F-563, EFS321, and EFS-521 purchased from DIC Corporation; the sensitizers include, but are not limited to, TPPA purchased from Takeda Chemical; the plasticizers and crack-resistant agents include, but are not limited to, polyethylene glycol dimethyl ether purchased from Shanghai Nobipure; and the crosslinking agents include, but are not limited to, trimethoxy[3-(phenylamino)propyl]silane purchased from Aladdin.

[0038] In a second aspect, the present invention provides a method for preparing a thick-film positive photoresist composition as described in the first aspect, the method comprising the following steps: mixing the components in the thick-film positive photoresist composition to obtain the thick-film positive photoresist composition.

[0039] Preferably, the mixing method includes: mixing by shaking on a shaker.

[0040] Preferably, the mixing time is ≥48 h, for example, it can be 48 h, 49 h, 50 h, 51 h, 52 h, 53 h, 54 h, 55 h, 56 h, 57 h, 58 h, 59 h or 60 h, etc.

[0041] Preferably, the mixing process further includes a post-processing step, wherein the post-processing method includes filtration using a filter membrane.

[0042] This invention does not impose any special limitations on the pore size of the filter membrane or the number of filtration cycles; commonly used filter membranes in the art are applicable. For example, the filter membrane has a pore size of 0.45 μm; and the filtration cycle is 3 times.

[0043] Thirdly, the present invention provides a photoresist layer, wherein the raw materials for preparing the photoresist layer include the thick-film positive photoresist composition as described in the first aspect.

[0044] Compared with the prior art, the present invention has the following beneficial effects: (1) By using benzophenone-modified phenolic resin, the benzophenone groups are grafted into the molecular chain of phenolic resin, which not only retains the light absorption advantage of benzophenone, but also achieves molecular-level uniform dispersion of benzophenone groups in the thick film positive photoresist composition, solves the problem of easy aggregation of free benzophenone compounds, improves the steepness and etching resistance of the photoresist layer, and improves the development effect of the photoresist layer pattern.

[0045] (2) By controlling the mass content of benzophenone groups in the matrix resin to be 0.8-7.5%, the present invention prepared a high-performance thick film positive photoresist composition, and then prepared a photoresist layer with high steepness, high resolution, good etching resistance and good development effect.

[0046] (3) The present invention designs a photosensitive compound by specifically selecting the photosensitive compound, and by combining a specific matrix resin and a specific photosensitive compound and controlling the amount of both within a specific range, a high-performance thick film positive photoresist composition is prepared, and then a photoresist layer with excellent comprehensive performance is prepared. Attached Figure Description

[0047] Figure 1 This is a top-view CD-SEM image of the photoresist layer provided in Application Example 1 of the present invention at a resolution of 8 μm; Figure 2 This is a SEM image of the photoresist layer provided in Application Example 1 of the present invention at a resolution of 8 μm, with a scale bar of 10.0 μm; Figure 3 This is a top-view CD-SEM image of the photoresist layer provided in Comparative Application Example 7 of the present invention at a resolution of 8 μm; Figure 4 This is a SEM image of the photoresist layer provided in Comparative Application Example 7 of the present invention at a resolution of 8 μm, with a scale bar of 10.0 μm. Detailed Implementation

[0048] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be considered as specific limitations thereof.

[0049] Preparation Example 1 This preparation example provides benzophenone-modified phenolic resin 1 and its synthesis method, which is as follows: (1) Synthesis of phenolic resin 1 In a 2000 mL four-necked flask equipped with a mechanical stirrer, temperature sensor, reflux condenser, and nitrogen protection system, m-cresol (200 g), p-cresol (300 g), formaldehyde aqueous solution (300 g, formaldehyde concentration 37 wt%), and oxalic acid catalyst (6.4 g) were added sequentially. The reaction system was stirred and heated to 95 °C, and the reaction was maintained at a constant temperature under reflux for 3 h. Subsequently, the reflux condenser was replaced with a distillation apparatus, and gradient temperature distillation was carried out under atmospheric pressure to gradually separate unreacted monomers and water until the system temperature reached 130 °C. Then, the process was switched to vacuum distillation, and the vacuum level of the system was gradually adjusted to 6.0 kPa using a vacuum system, while the material temperature was increased to 180 °C at a heating rate of 0.5 °C / min, and this temperature and vacuum condition were maintained for 30 h. In the final stage, the material temperature is raised to 210℃ at a heating rate of 2℃ / min to complete the entire polycondensation reaction process. After heating is terminated, the vacuum system is released, and the molten resin is quickly transferred to a polytetrafluoroethylene mold or stainless steel tray for rapid cooling and solidification. After mechanical crushing, a light yellow powdered phenolic resin 1 (224g) is obtained. Gel permeation chromatography (GPC) analysis shows that its weight-average molecular weight (Mw) ranges from 30,000 to 45,000 g / mol, and the PDI is 1.8.

[0050] (2) Synthesis of benzophenone-modified phenolic resin 1 In a 1000 mL four-necked flask equipped with a mechanical stirrer, temperature sensor, reflux condenser, and nitrogen protection system, 100 g of phenolic resin 1 was first added, followed by 200 mL of N,N-dimethylformamide to completely dissolve it. Then, 1 g of [unspecified ingredient] was added to the system. Nitrogen gas was introduced into the system for 5 minutes under stirring to fully replace the air in the system. Then the reactants were heated to 75°C and refluxed for 18 hours while maintaining this temperature range. After the reaction was completed, the system was cooled to room temperature, and solid impurities were removed by filtration. The filtrate was washed with deionized water several times and then concentrated and recrystallized to obtain benzophenone-modified phenolic resin 1 with a benzophenone group content of 0.8 wt%.

[0051] Preparation Example 2 This preparation example provides benzophenone-modified phenolic resin 2 and its synthesis method, which is as follows: (1) Synthesis of phenolic resin 2 In a 2000 mL four-necked flask equipped with a mechanical stirrer, temperature sensor, reflux condenser, and nitrogen protection system, m-cresol (200 g), p-cresol (300 g), formaldehyde aqueous solution (300 g, formaldehyde concentration 37 wt%), and oxalic acid catalyst (6.4 g) were added sequentially. The reaction system was stirred and heated to 90 °C, and the reaction was maintained at a constant temperature under reflux for 3 h. Subsequently, the reflux condenser was replaced with a distillation apparatus, and gradient temperature distillation was carried out under atmospheric pressure to gradually separate unreacted monomers and water until the system temperature reached 125 °C. Then, the process was switched to vacuum distillation, and the vacuum level of the system was gradually adjusted to 6.0 kPa using a vacuum system, while the material temperature was increased to 180 °C at a heating rate of 0.5 °C / min, and this temperature and vacuum condition were maintained for 30 h. In the final stage, the material temperature is raised to 210℃ at a heating rate of 2℃ / min to complete the entire polycondensation reaction process. After heating is terminated, the vacuum system is released, and the molten resin is quickly transferred to a polytetrafluoroethylene mold or stainless steel tray for rapid cooling and curing. After mechanical crushing, a light yellow powdered phenolic resin 2 (235 g) is obtained. Gel permeation chromatography (GPC) analysis shows that its weight-average molecular weight (Mw) ranges from 30,000 to 35,000 g / mol, and the PDI is 1.7.

[0052] (2) Synthesis of benzophenone-modified phenolic resin 2 The synthesis method of benzophenone-modified phenolic resin 2 is the same as that in Preparation Example 1, except that the amount of phenolic resin 2 participating in the reaction is adjusted to 80 g, so as to obtain benzophenone-modified phenolic resin 2 with a benzophenone group content of 0.1 wt%.

[0053] Preparation Example 3 This preparation example provides benzophenone-modified phenolic resin 3 and its synthesis method, which is as follows: (1) Synthesis of phenolic resin 3 In a 2000 mL four-necked flask equipped with a mechanical stirrer, temperature sensor, reflux condenser, and nitrogen protection system, m-cresol (200 g), p-cresol (300 g), formaldehyde aqueous solution (300 g, formaldehyde concentration 37 wt%), and oxalic acid catalyst (6.4 g) were added sequentially. The reaction system was stirred and heated to 95 °C, and the reaction was maintained at a constant temperature under reflux for 3 h. Subsequently, the reflux condenser was replaced with a distillation apparatus, and gradient temperature distillation was carried out under atmospheric pressure to gradually separate unreacted monomers and water until the system temperature reached 130 °C. Then, the process was switched to vacuum distillation, and the vacuum level of the system was gradually adjusted to 6.0 kPa using a vacuum system, while the material temperature was increased to 180 °C at a heating rate of 0.5 °C / min, and this temperature and vacuum condition were maintained for 30 h. In the final stage, the material temperature is raised to 200℃ at a heating rate of 2℃ / min to complete the entire polycondensation reaction process. After heating is terminated, the vacuum system is released, and the molten resin is quickly transferred to a polytetrafluoroethylene mold or stainless steel tray for rapid cooling and curing. After mechanical crushing, a light yellow powdered phenolic resin 3 (235 g) is obtained. Gel permeation chromatography (GPC) analysis shows that its weight-average molecular weight (Mw) ranges from 45,000 to 50,000 g / mol, and the PDI is 1.9.

[0054] (2) Synthesis of benzophenone-modified phenolic resin 3 The synthesis method of benzophenone-modified phenolic resin 3 is the same as that in Preparation Example 1, except that the amount of phenolic resin 2 participating in the reaction is adjusted to 35 g, and benzophenone-modified phenolic resin 3 with a benzophenone group content of 2.2 wt% is obtained.

[0055] Preparation Example 4 This preparation example provides benzophenone-modified phenolic resin 4 and its synthesis method, which is as follows: In a 1000 mL four-necked flask equipped with a mechanical stirrer, temperature sensor, reflux condenser, and nitrogen protection system, 16 g of phenolic resin 4 (purchased from Asahi Organic Materials, brand name NT31B15G, number average molecular weight 31000 g / mol, PDI 1.4) was first added, followed by 200 mL of N,N-dimethylformamide to completely dissolve it. Then, 1 g of [unspecified ingredient] was added to the system. Nitrogen gas was introduced into the system for 5 minutes under stirring to fully replace the air in the system. Then the reactants were heated to 75°C and refluxed for 18 hours while maintaining this temperature range. After the reaction was completed, the system was cooled to room temperature, and solid impurities were removed by filtration. The filtrate was washed with deionized water several times and then concentrated and recrystallized to obtain benzophenone-modified phenolic resin 4 with a benzophenone group content of 4.8 wt%.

[0056] Preparation Example 5 This preparation example provides benzophenone-modified phenolic resin 5 and its synthesis method, which is as follows: (1) Synthesis of phenolic resin 5 In a 2000 mL four-necked flask equipped with a mechanical stirrer, temperature sensor, reflux condenser, and nitrogen protection system, m-cresol (200 g), p-cresol (300 g), formaldehyde aqueous solution (300 g, formaldehyde concentration 37 wt%), and oxalic acid catalyst (6.4 g) were added sequentially. The reaction system was stirred and heated to 90 °C, and the reaction was maintained at a constant temperature under reflux for 3 h. Subsequently, the reflux condenser was replaced with a distillation apparatus, and gradient temperature distillation was carried out under atmospheric pressure to gradually separate unreacted monomers and water until the system temperature reached 130 °C. Then, the process was switched to vacuum distillation, and the vacuum level of the system was gradually adjusted to 6.0 kPa using a vacuum system, while the material temperature was increased to 180 °C at a heating rate of 0.5 °C / min, and this temperature and vacuum condition were maintained for 30 h. In the final stage, the material temperature is raised to 210℃ at a heating rate of 2℃ / min to complete the entire polycondensation reaction process. After heating is terminated, the vacuum system is released, and the molten resin is quickly transferred to a polytetrafluoroethylene mold or stainless steel tray for rapid cooling and curing. After mechanical crushing, a light yellow powdered phenolic resin 5 (230 g) is obtained. Gel permeation chromatography (GPC) analysis shows that its weight-average molecular weight (Mw) ranges from 9000 to 11000 g / mol, and the PDI is 1.5.

[0057] (2) Synthesis of benzophenone-modified phenolic resin 5 The synthesis method of benzophenone-modified phenolic resin 5 is the same as that in Preparation Example 1, except that the amount of phenolic resin 5 participating in the reaction is adjusted to 10 g, and benzophenone-modified phenolic resin 5 with a benzophenone group content of 7.4 wt% is obtained.

[0058] Preparation Example 6 This preparation example provides benzophenone-modified phenolic resin 6 and its synthesis method, which is as follows: (1) Synthesis of phenolic resin 6 In a 2000 mL four-necked flask equipped with a mechanical stirrer, temperature sensor, reflux condenser, and nitrogen protection system, m-cresol (200 g), p-cresol (300 g), formaldehyde aqueous solution (300 g, formaldehyde concentration 37 wt%), and oxalic acid catalyst (6.4 g) were added sequentially. The reaction system was stirred and heated to 90-95 °C, and the reaction was maintained at a constant temperature under reflux for 3 hours. Subsequently, the reflux condenser was replaced with a distillation apparatus, and gradient temperature distillation was carried out under atmospheric pressure to gradually separate unreacted monomers and water until the system temperature reached 130 °C. Then, the process was switched to vacuum distillation, and the vacuum level of the system was gradually adjusted to 6.0 kPa using a vacuum system, while the material temperature was increased to 180 °C at a heating rate of 0.5 °C / min, and this temperature and vacuum condition were maintained for 30 hours. In the final stage, the material temperature is raised to 200℃ at a heating rate of 2℃ / min to complete the entire polycondensation reaction process. After heating is terminated, the vacuum system is released, and the molten resin is quickly transferred to a polytetrafluoroethylene mold or stainless steel tray for rapid cooling and curing. After mechanical crushing, a light yellow powdery phenolic resin 6 (212 g) is obtained. Gel permeation chromatography (GPC) analysis shows that its weight-average molecular weight (Mw) is 3000~3500 g / mol and its PDI is 1.4.

[0059] (2) Synthesis of benzophenone-modified phenolic resin 6 The synthesis method of benzophenone-modified phenolic resin 6 is the same as in Preparation Example 1, except that the amount of phenolic resin 5 participating in the reaction is adjusted to 37 g, and the amount of phenolic resin 5 participating in the reaction is adjusted... The amount of benzophenone modified phenolic resin 6 with a benzophenone group content of 4.2wt% was obtained by using 2 g of benzophenone.

[0060] Comparative Preparation Example 1 This comparative preparation example provides benzophenone-modified phenolic resin A and its synthesis method, which is as follows: The synthesis method of benzophenone-modified phenolic resin A is the same as that in Preparation Example 1, except that the amount of phenolic resin 1 participating in the reaction is adjusted to 120 g, and benzophenone-modified phenolic resin A with a benzophenone group content of 0.67 wt% is obtained.

[0061] Comparative Preparation Example 2 This comparative preparation example provides benzophenone-modified phenolic resin B and its synthesis method, which is as follows: The synthesis method of benzophenone-modified phenolic resin B is the same as that in Preparation Example 1, except that the amount of phenolic resin 1 participating in the reaction is adjusted to 8 g, and benzophenone-modified phenolic resin A with a benzophenone group content of 9.0 wt% is obtained.

[0062] The sources of some components in the following examples and comparative examples are described in Table 1 below: Table 1 Examples 1-9, Comparative Examples 1-5 Examples 1-9 and Comparative Examples 1-5 respectively provide a thick film positive photoresist composition and its preparation method. The thick film positive photoresist composition is composed of a matrix resin, a photosensitive compound, solvent A and a leveling agent. The specific selection and amount (parts by weight) of each component are detailed in Tables 2-3 below. The preparation method of the above-mentioned thick film positive photoresist composition is as follows: after mixing the components of the thick film positive photoresist composition, the mixture is placed on a shaker and shaken for 50 h, and filtered three times with a filter membrane with a pore size of 0.45 μm to obtain the thick film positive photoresist composition.

[0063] Table 2 Table 3 Application Example 1 This application example provides a photoresist layer, the preparation method of which is as follows: Using an 8-inch silicon wafer as a substrate, a thick-film positive photoresist composition provided in Example 1 is pre-spin-coated onto one side of the silicon wafer at a rotation speed of 800 rpm. Then, after homogenization at a main rotation speed of 2000 rpm for 30 seconds, it is baked at 100°C for 120 seconds to obtain the photoresist layer. The thickness of the photoresist layer is measured to be 12 μm using an F-50 film thickness gauge. Then, it is placed in an i-line stepper lithography machine at an exposure dose of 200 mJ / cm². 2 Expose and develop (using 2.38wt% TMAH developer) for 80 s to obtain the photoresist layer.

[0064] Application Examples 2-9, Comparison Application Examples 1-5 Application Examples 2-9 and Comparative Application Examples 1-5 each provide a photoresist layer. The only difference from Application Example 1 is that the thick film positive photoresist composition provided in Example 1 is replaced with the thick film positive photoresist composition provided in Examples 2-9 and Comparative Examples 1-5. All other conditions are the same as in Application Example 1.

[0065] The resolution and morphology of the photoresist layer pattern provided in Application Example 1 were observed using a feature-size scanning electron microscope (CD-SEM). The CD-SEM image of the photoresist layer pattern viewed from a top perspective (i.e., a top-view CD-SEM image of the photoresist layer pattern) is shown below. Figure 1 The morphology of the photoresist layer slice provided in Application Example 1 was observed using a scanning electron microscope (SEM), and the results are as follows. Figure 2 As shown. By Figure 1 and Figure 2 It can be seen that the thick-film positive photoresist composition prepared by the present invention through the use of benzophenone-modified phenolic resin and by controlling the benzophenone group in the matrix resin within a specific content has excellent comprehensive performance, thereby enabling the photoresist layer to open after development with little top loss and high steepness (i.e., high sidewall verticality), indicating good etching resistance.

[0066] The resolution and morphology of the photoresist layer pattern provided in Application Example 7 were observed using a feature-size scanning electron microscope (CD-SEM). The CD-SEM image of the photoresist layer pattern viewed from a top perspective (i.e., a top-view CD-SEM image of the photoresist layer pattern) is shown below. Figure 3 The morphology of the photoresist layer slice provided in Application Example 7 was observed using a scanning electron microscope (SEM), and the results are as follows. Figure 4 As shown. By Figure 3 and Figure 4 It is known that when the content of benzophenone groups in the matrix resin is high, the photoresist layer can be opened after development, but the footing difference is large and the steepness of the photoresist layer deteriorates.

[0067] The resolution and morphology of the photoresist layer patterns provided in other application examples and comparative application examples were observed using a feature-size scanning electron microscope (CD-SEM); then, the morphology of the sections was observed using a scanning electron microscope (SEM), and their performance was characterized as follows: Whether it can be opened after development: If there are clear morphological boundaries on the CD-SEM image, it indicates that it can be opened (e.g., Figure 1 If there are no obvious morphological boundaries (as shown), it means that the surface was not opened after development. Top loss phenomenon (white border width): The white border width on the image is measured using CD-SEM. If the white border width is large, it indicates that the top loss is more severe. In application example 1: white border width = (bottom width - top width) / 2; in application examples 2-9 and comparison application examples 1-5, white border width = (top width of application example 1 - top width of the corresponding application example or comparison application example) / 2. For example, the white border width of application example 2 = (top width of application example 1 - top width of application example 2) / 2. Footing difference: The footing difference is measured using SEM (scanning electron microscope). In Application Example 1, the footing difference = (bottom width - top width) / 2. In Application Examples 2-9 and Comparative Application Examples 1-5, the white border width = (bottom width of the corresponding application example or corresponding comparative application example - bottom width of Application Example 1) / 2. For example, the white border width of Application Example 2 = (bottom width of Application Example 2 - bottom width of Application Example 1) / 2. Sidewall vertical angle: Test the angle between the sidewall and the bottom plane: The above performance tests are detailed in Table 4 below: Table 4 As can be seen from the above, this invention, by designing the specific composition of the thick-film positive photoresist composition and further using benzophenone-modified phenolic resin, not only retains the light absorption advantage of benzophenone but also achieves molecular-level uniform dispersion of benzophenone in the thick-film positive photoresist composition, solving the problem of easy agglomeration of benzophenone and improving the uniformity of the distribution of the benzophenone structure in the thick-film positive photoresist composition. At the same time, through the combination with other components, it improves the steepness, resolution, and etching resistance of the photoresist layer, and also improves the development effect of the photoresist layer pattern.

[0068] By comparing Application Examples 1 and 3-7, and Comparative Application Examples 1-2, it can be seen that the present invention, by controlling the mass content of benzophenone groups in the matrix resin to 0.8-7.5%, prepared a high-performance thick-film positive photoresist composition, thereby obtaining a photoresist layer with high steepness, high resolution, good etching resistance, and good development effect. Furthermore, by comparing Application Examples 1 and 3-7, it can be seen that the present invention, by controlling the mass content of benzophenone groups in the matrix resin to 1.0-5.0%, further improved the overall performance of the thick-film positive photoresist composition and the photoresist layer.

[0069] By comparing Application Example 1 and Application Example 8, it can be seen that the preferred matrix resin of the present invention is benzophenone-modified phenolic resin, and the prepared photoresist layer has better steepness, etching resistance and development effect.

[0070] By comparing Application Examples 1 and 9 with Comparative Application Examples 4-5, it can be seen that the present invention has designed a high-performance thick-film positive photoresist composition and photoresist by specifically selecting photosensitive compounds.

[0071] In summary, this invention utilizes benzophenone-modified phenolic resin to graft benzophenone groups into the phenolic resin molecular chain. This retains the light absorption advantages of benzophenone while achieving molecular-level uniform dispersion of benzophenone groups in the thick-film positive photoresist composition. This solves the problem of benzophenone's tendency to agglomerate, improves the steepness and etching resistance of the photoresist layer, and enhances the development effect of the photoresist layer pattern.

[0072] The applicant declares that the detailed process flow of this invention is illustrated by the above embodiments, but this invention is not limited to the above detailed process flow, that is, it does not mean that this invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product of this invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. A thick-film positive photoresist composition, characterized in that, The thick-film positive photoresist composition comprises 70-90 parts of a matrix resin, 10-30 parts of a photosensitive compound, and 100-150 parts of solvent A; The matrix resin includes benzophenone-modified phenolic resin and optionally unmodified phenolic resin; based on the mass percentage of the matrix resin as 100%, the mass percentage of benzophenone groups in the matrix resin is 0.8-7.5%; The photosensitive compound includes non-benzophenone photosensitive compounds and optional benzophenone compounds, wherein the mass percentage of the benzophenone compound is ≤3.0% based on the mass percentage of the photosensitive compound being 100%.

2. The thick-film positive photoresist composition according to claim 1, characterized in that, Based on a matrix resin mass percentage of 100%, the mass percentage of benzophenone groups in the matrix resin is 1.0-5.0%. Preferably, the matrix resin is benzophenone-modified phenolic resin.

3. The thick-film positive photoresist composition according to claim 1 or 2, characterized in that, The raw materials for preparing the benzophenone-modified phenolic resin include phenolic resin and ; Preferably, the phenolic resin and The mass ratio is (10-100):1; Preferably, the weight-average molecular weight of the phenolic resin is 300-90000 g / mol; Preferably, the molecular weight distribution of the phenolic resin is ≤2.

5.

4. The thick-film positive photoresist composition according to any one of claims 1-3, characterized in that, The benzophenone-modified phenolic resin was prepared by the following method, which includes the following steps: After mixing phenolic resin and solvent B, add... The reaction yields the benzophenone-modified phenolic resin. Preferably, solvent B comprises any one or a combination of at least two of N,N-dimethylformamide, propylene glycol methyl ether, propylene glycol methyl ether acetate, ethylene glycol monomethyl ether acetate, butyl acetate, methyl isobutyl ketone, γ-butyrolactone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, dimethylformamide, toluene, or isopropanol. Preferably, the reaction is carried out in a protective atmosphere; Preferably, the reaction temperature is 65-85℃ and the time is 16-20 h; Preferably, the reaction further includes a post-processing step, wherein the post-processing method includes cooling, filtration, washing, concentration, and recrystallization.

5. The thick-film positive photoresist composition according to any one of claims 1-4, characterized in that, The weight-average molecular weight of the unmodified phenolic resin is 300-90000 g / mol.

6. The thick-film positive photoresist composition according to any one of claims 1-4, characterized in that, The non-benzophenone photosensitive compounds include resin-type non-benzophenone photosensitive compounds; Preferably, solvent A is selected from any one or a combination of at least two of propylene glycol methyl ether acetate, propylene glycol methyl ether, propylene glycol methyl ether acetate, ethylene glycol monomethyl ether acetate, butyl acetate, methyl isobutyl ketone, γ-butyrolactone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, dimethylformamide, toluene, or isopropanol.

7. The thick-film positive photoresist composition according to any one of claims 1-6, characterized in that, The thick-film positive photoresist composition also includes 0.1-3 parts by weight of an additive; Preferably, the additives include any one or a combination of at least two of the following: leveling agents, sensitizers, plasticizers and crack-resistant agents, and crosslinking agents.

8. A method for preparing a thick-film positive photoresist composition as described in any one of claims 1-7, characterized in that, The preparation method includes the following steps: The components of the thick film positive photoresist composition are mixed to obtain the thick film positive photoresist composition.

9. The preparation method according to claim 8, characterized in that, The mixing method includes: mixing by shaking on a shaker; Preferably, the mixing time is ≥48 h; Preferably, the mixing process further includes a post-processing step, wherein the post-processing method includes filtration using a filter membrane.

10. A photoresist layer, characterized in that, The raw materials for preparing the photoresist layer include the thick-film positive photoresist composition as described in any one of claims 1-7.

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