Positive chemical amplification photoresist composition, micro-pattern structure and preparation method

Abstract

The invention discloses a positive chemical amplification photoresist composition, a micro-pattern structure and a preparation method, and the positive chemical amplification photoresist composition at least comprises the following components: acrylic resin containing an acid unstable group; a photoacid generator; and an organic solvent. The composition aims to solve the problems of single thick film coating, high aspect ratio patterning and high residual film rate by optimizing a chemical system and rheological properties. After the composition is subjected to exposure (the dosage is 200mJ / cm < 2 >-600mJ / cm < 2 >), post-exposure baking (PEB 90-120 DEG C) and alkaline development, a high-precision micro-graphic mold with a vertical side wall and an aspect ratio of not less than 6: 1 can be efficiently prepared, and the residual film rate of an unexposed area after development is not less than 90%.

Description

Technical Field

[0001] This invention belongs to the field of photolithography materials technology, specifically relating to a positive chemical amplification photoresist composition, micro-pattern structure, and preparation method. Background Technology

[0002] In the fields of printed circuit board (PCB), micro-electro-mechanical systems (MEMS), and especially advanced wafer-level packaging (WLP), such as fan-out wafer-level packaging (FOWLP) and 2.5D / 3D heterogeneous integration, the demand for high-density, high-performance metal interconnect structures is increasingly urgent. To meet the requirements of next-generation electronic products for high current carrying capacity and low signal loss (e.g., reduced RC delay), it is necessary to fabricate metal conductive lines with high thickness (typically tens of micrometers) and high aspect ratio (AR≥6:1). These thick-film metal structures are typically achieved through a "patterning plating" process, which requires first using photolithography to precisely form a photoresist mold on a substrate with a thickness ranging from 50 to 80 micrometers. This mold must have steep sidewall profiles and excellent mechanical stability to withstand subsequent long-duration, highly corrosive metal electrodeposition processes (e.g., copper plating). Therefore, the performance of photoresist materials directly determines the final electrical performance and manufacturing yield of advanced electronic components.

[0003] However, existing technologies face multiple challenges in materials science and process engineering for fabricating high-quality thick-film photoresist molds for patterned electroplating. While traditional non-chemically amplified photoresists (such as those based on DNQ / phenolic resin systems) exhibit good adhesion and electroplating resistance, their inherent low sensitivity results in excessively long exposure times and extremely low production efficiency when forming films thicker than 50 micrometers, and makes it difficult to ensure light penetration across the entire thickness. To improve production efficiency, chemically amplified photoresists (CARs) have been introduced, significantly reducing the exposure dose through a catalytic amplification mechanism. However, existing positive CAR systems still have fundamental limitations in thick-film applications.

[0004] First, in order to achieve a thickness of 50μm to 80μm in a single spin coating, the photoresist composition must have an extremely high concentration of solid components (solid content is usually above 30%) and a high viscosity (e.g., above 1000cP). This greatly increases the difficulty of the spin coating process and easily leads to defects such as radial stripes, comet tails or edge bead during the coating process, affecting the uniformity of the film.

[0005] Secondly, during thick film exposure, the absorption of exposure light by the photoresist material, according to the Beer-Lambert Law, inevitably leads to a decrease in light intensity along the thickness direction. If this difference in light intensity is not properly controlled, the top and bottom of the photoresist layer will receive different effective exposure doses. Consequently, in the post-exposure baking (PEB) step, the non-uniformity of acid diffusion will cause severe distortion of the final pattern sidewall contour, such as "T-top" caused by overexposure at the top or "undercut" caused by underexposure at the bottom. This will fail to meet the strict requirements of electroplating for sidewall perpendicularity (usually required to be better than 85 degrees).

[0006] Finally, high aspect ratio photoresist structures (AR≥6:1) are highly susceptible to mechanical failure during alkaline development and electroplating due to factors such as internal stress, solvent penetration, and interfacial reactions. Existing CAR resins, lacking sufficient glass transition temperature (Tg) and strong adhesion to substrates (especially copper-clad substrates), will struggle to resist swelling during development or thermal stress during electroplating, ultimately resulting in pattern collapse or complete peeling, severely limiting the application of high-performance micropatterning technology.

[0007] Therefore, there is an urgent need in the field for a novel positive chemical amplification photoresist composition that can achieve synergistic optimization of rheological properties, exposure penetration depth and pattern mechanical stability while ensuring high sensitivity and high yield, so as to efficiently prepare micro-pattern molds with a thickness of 500μm-80μm, high aspect ratio (AR≥6:1) and no defects. Summary of the Invention

[0008] The purpose of this invention is to provide a positive chemical amplification photoresist composition, micro-pattern structure and preparation method. This composition solves the problems of single-pass thick film coating, high aspect ratio patterning and high residual film rate by optimizing the chemical system and rheological properties. It can be applied to pattern electroplating processes for advanced packaging, microelectromechanical systems (MEMS) and high-density printed circuit boards (HD-PCB) that require high precision and high integration.

[0009] To achieve the above objectives, a specific embodiment of the present invention provides the following technical solution:

[0010] A positive chemical amplification photoresist composition, the positive chemical amplification photoresist composition comprising at least the following components: acrylic resin, the acrylic resin containing acid-indestabilizing groups; a photoacid-generating agent; and an organic solvent.

[0011] In one or more embodiments of the present invention, the raw materials of the acrylic resin include monomer A, which contains acid-instable groups; monomer B, which contains ester groups; and monomer C, which contains cyclic structural groups.

[0012] Based on the total molar amount of the acrylic resin, the molar percentage of monomer A is 20%-40%, the molar percentage of monomer B is 40%-60%, and the molar percentage of monomer C is 5%-20%.

[0013] In one or more embodiments of the present invention, monomer A is at least one selected from tert-butyl methacrylate, cyclohexyl ethyl methacrylate, tetrahydrofuran methacrylate, tetrahydropyran methacrylate, and adamantyl methacrylate.

[0014] The monomer B is methyl methacrylate;

[0015] The monomer C is glycidyl methacrylate.

[0016] In one or more embodiments of the present invention, the acrylic resin is prepared as follows:

[0017] Mix monomers A, B, and C, add solvent and initiator under a nitrogen atmosphere, heat to 70℃-80℃, react for 13-15 hours, and then cool to room temperature.

[0018] The reaction solution was mixed with pure water to precipitate the precipitate, which was then filtered. The precipitate was dissolved in tetrahydrofuran, and then pure water was added again to precipitate the precipitate. This process was repeated several times to obtain the precipitate.

[0019] The precipitate was dried to obtain acrylic resin.

[0020] In one or more embodiments of the present invention, the acrylic resin has a number-average molecular weight of 5,000-50,000, a weight-average molecular weight of 20,000-60,000, and a molecular weight distribution index of 1.5-2.5.

[0021] In one or more embodiments of the present invention, the solid content of the positive chemical amplification photoresist composition is 30wt%-50wt%; and / or,

[0022] The viscosity of the positive chemical amplification photoresist composition at 25°C is 500cp-2000cp.

[0023] In one or more embodiments of the present invention, the photoacid-producing agent is at least one of a sulfonium salt compound and an iodonium salt compound; and / or,

[0024] Based on the solid components in the positive chemical amplification photoresist composition, the photoacid-generating agent accounts for 1wt%-5wt% by mass; and / or,

[0025] The organic solvent is at least one of propylene glycol monomethyl ether acetate, γ-butyrolactone, and ethyl lactate.

[0026] In one or more embodiments of the present invention, the positive chemical amplification photoresist composition further includes at least one of an alkaline quencher, a leveling agent, and an adhesion promoter, wherein the alkaline quencher is an organic amine compound, the leveling agent is a fluorinated leveling agent and / or a silicon-containing leveling agent, and the adhesion promoter is a silane group compound.

[0027] Based on the solid components in the positive chemical amplification photoresist composition, the alkaline quencher accounts for 0.1wt%-2wt% by mass, the leveling agent accounts for 0.1wt%-1wt% by mass, and the adhesion promoter accounts for 0.1wt%-1wt% by mass.

[0028] Another specific embodiment of the present invention provides the following technical solution:

[0029] A method for preparing a positive chemical amplification photoresist composition, comprising mixing at least acrylic resin, photoacid generator and organic solvent in a specified ratio to obtain a positive chemical amplification photoresist composition.

[0030] Another specific embodiment of the present invention provides the following technical solution:

[0031] A micropattern structure, wherein the raw material of the micropattern structure comprises at least a positive chemical amplification photoresist composition;

[0032] The thickness of the micro-patterned structure is 50μm-80μm, the aspect ratio is greater than or equal to 6:1, and the residual film rate is greater than or equal to 90%.

[0033] Another specific embodiment of the present invention provides the following technical solution:

[0034] A method for fabricating a micro-patterned structure, the method comprising the following steps:

[0035] Coating: A positive chemical amplification photoresist composition is coated onto a substrate to form a photoresist layer;

[0036] Soft baking;

[0037] exposure;

[0038] Baking after exposure;

[0039] Development yields micro-patterned structures.

[0040] In one or more embodiments of the present invention, in the coating step, the coating thickness is 50 μm-80 μm; and / or,

[0041] In the softening step, the temperature is 120℃-140℃, and the time is 2min-5min; and / or,

[0042] In the exposure step, the wavelength of the exposure light source is 300nm-450nm, and the exposure dose is 200mJ / cm². 2 -600mJ / cm 2 ; and / or,

[0043] In the post-exposure baking step, the temperature is 90℃-110℃, and the time is 1min-3min; and / or,

[0044] In the developing step, the developing solution is an aqueous solution of 2wt%-3wt% tetramethylammonium hydroxide, and the time is 1min-3min.

[0045] Compared with existing technologies, this invention, through synergistic optimization of the molecular weight and acid-labile group content of acrylic resin, the type and amount of photoacid-generating agent, and the solvent system and solid content, can achieve at least the following beneficial effects:

[0046] 1. High-efficiency thick film forming: The photoresist composition has optimized rheological properties and high solid content, which can stably form a uniform thick film of 50μm-80μm through a single spin coating process, which significantly simplifies the production process and improves production efficiency.

[0047] 2. Excellent patterning performance: The thick film pattern formed by the composition has steep sidewalls and high resolution, with an aspect ratio of over 6:1. At the same time, the residual film rate in the unexposed area after development is over 90%, indicating that it has excellent adhesion and mechanical strength, which can effectively prevent the pattern from collapsing or peeling off, providing a solid foundation for subsequent high-quality electroplating copper processes.

[0048] 3. Excellent process compatibility: The composition has good sensitivity to standard i-line (365nm) exposure equipment, a wide process window, is easy to implement on existing production lines, and is well compatible with subsequent copper plating processes, making it suitable for manufacturing high-density printed circuit boards. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a micro-pattern structure diagram prepared using the positive chemical amplification photoresist composition in Example 1 of this invention;

[0051] Figure 2This is a diagram of the micro-pattern structure prepared using the positive chemical amplification photoresist composition in Comparative Example 1. Detailed Implementation

[0052] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0053] One specific embodiment of the present invention provides a positive chemical amplification photoresist composition, comprising at least the following components: acrylic resin, wherein the acrylic resin contains acid-instable groups; a photoacid-generating agent; and an organic solvent.

[0054] Furthermore, acrylic resin serves as the film-forming matrix in the composition, and its properties directly determine the adhesion, mechanical strength, etch resistance, and patterning capability of the photoresist. Acrylic resin contains acid-insecure groups, which are stable under normal conditions but undergo chemical decomposition (i.e., "deprotection") under the action of acidic catalysts (generated by photoacid-generating agents) and heat (baking after exposure), thereby altering the resin's solubility in the developer.

[0055] The number-average molecular weight (Mn) of the acrylic resin is controlled within the range of 5,000-50,000, preferably 10,000-30,000. If the molecular weight is below 5,000, the film-forming properties of the resin will deteriorate, resulting in insufficient mechanical strength of the formed thick film, and pattern collapse is likely to occur during development. If the molecular weight is above 50,000, the solubility of the resin will decrease, leading to excessively high photoresist viscosity, making uniform spin coating difficult, and potentially reducing the development rate. The weight-average molecular weight (Mw) of the acrylic resin is preferably 20,000-60,000, and the molecular weight distribution index (Mw / Mn) is in the range of 1.5-2.5.

[0056] Furthermore, the acrylic resin is a copolymer of monomers A, B, and C. Monomer A contains an acid-labile group, specifically at least one of t-butyl methacrylate (tBMA), cyclohexyl methacrylate, tetrahydrofuran methacrylate, tetrahydropyran methacrylate, and adamantyl methacrylate. For example, t-butyl methacrylate provides an acid-labile group, namely a tert-butyloxycarbonyl group, which, under acid catalysis, loses isobutylene and transforms into a basic-loving carboxyl group, thereby making the resin soluble in alkaline developing solution in the exposure area.

[0057] Monomer B is methyl methacrylate (MMA), used to adjust the overall physical properties of the resin, such as glass transition temperature (Tg), mechanical strength, and adhesion to the substrate.

[0058] Monomer C is glycidyl methacrylate (GMA), which contains epoxy groups that can significantly enhance the adhesion of the resin to metal substrates (such as copper), which is crucial for preventing the thick film pattern from peeling off during development and electroplating.

[0059] The content of acid-labile groups has a decisive impact on the performance of photoresist. In this invention, the content of monomers containing acid-labile groups (such as tBMA) accounts for 20%-40% of the total molar amount of the resin. If the content is less than 20%, the solubility difference between the exposed and unexposed areas is not large enough, resulting in a decrease in pattern contrast. If the content is greater than 40%, the resin is too hydrophobic, which may affect its dissolution rate in alkaline developer and may cause excessive volume shrinkage due to deprotection reaction, leading to pattern defects.

[0060] Further, the preparation of acrylic resin is as follows: monomers A, B, and C are mixed, and under a nitrogen atmosphere, a solvent (such as methanol) and an initiator (such as azobisisobutyronitrile) are added. The mixture is heated to 70℃-80℃ and reacted for 13-15 hours. The reaction is then stopped and cooled to room temperature. The reaction solution is mixed with pure water to precipitate the precipitate, which is then filtered. The precipitate is dissolved in an equal mass of tetrahydrofuran, and then pure water is added again to precipitate the precipitate. This process is repeated several times to obtain the precipitate. The precipitate is then placed in a vacuum oven and dried at a low temperature for 45-50 hours to obtain acrylic resin.

[0061] Furthermore, the photoacid generator (PAG) is a core component of chemically amplified photoresists. When exposed to light of a specific wavelength (such as ultraviolet light), it decomposes to produce a strong acid. This strong acid acts as a catalyst in the subsequent baking process, initiating a deprotection reaction of a large number of acid-unstable groups on the acrylic resin, thereby achieving a "chemical amplification" effect and greatly improving the sensitivity of the photoresist.

[0062] Photoacid generators should have absorption in the wavelength range of 300-450 nm to match commonly used photolithography exposure light sources, such as g-line (436 nm), h-line (405 nm), and i-line (365 nm). For thick-film photoresists, to ensure that light can penetrate the entire film layer, PAGs with good absorption at longer wavelengths (such as i-line) and high transparency of the photoresist host resin in this band are generally preferred.

[0063] Photoacid generators can be selected from sulfonium salts or iodonium salts, such as triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium perfluorobutylsulfonate or combinations thereof, diphenyliodonium perfluorooctylsulfonate, and diphenyliodonium hexafluoroantimonate. These PAGs have advantages such as high acid generation efficiency, good thermal stability, and excellent compatibility with resins. The dosage can be 1wt%-5wt% of the total mass of the solid components (resin, PAG, and other solid additives), preferably 1.5wt%-3wt%. Too low a dosage will result in insufficient acid concentration, leading to decreased sensitivity and incomplete deprotection; too high a dosage may cause excessive acid diffusion, reducing pattern resolution and potentially affecting the storage stability of the photoresist.

[0064] Furthermore, organic solvents are used to dissolve all solid components in the photoresist, forming a homogeneous solution. The viscosity of the photoresist is controlled by adjusting its content to suit coating processes such as spin coating. For preparing thick films, high-solids-content photoresist solutions are required; therefore, the solvent must have excellent solubility for components such as resins and PAG.

[0065] The organic solvent can be selected from propylene glycol monomethyl etheracetate (PGMEA), gamma-butyrolactone (GBL), ethyl lactate (EL), or mixtures thereof. These solvents have high boiling points and suitable evaporation rates, which helps to form a smooth, uniform, and pinhole-free thick film after spin coating and soft baking.

[0066] To form a 50μm-80μm thick film in a single spin coating process, the concentration (solid content) of the solid components in the photoresist composition is usually high, ranging from 30wt% to 50wt%, preferably 35wt% to 45wt%. By precisely controlling the solid content and the spin coating speed, the target thickness of the film can be stably obtained.

[0067] Furthermore, one or more additives may be optionally added to further optimize the performance of the photoresist composition.

[0068] Furthermore, the additive can be an alkaline quencher. In chemically amplified photoresists, the acid generated in the exposed areas diffuses during the post-exposure bake (PEB) process. Moderate diffusion helps smooth the standing wave effect, but excessive diffusion blurs the pattern lines and reduces resolution. Alkaline quenchers can neutralize a small amount of acid that diffuses into the unexposed areas, thereby precisely controlling the catalytic reaction range of the acid and improving the clarity of the pattern outline and the accuracy of dimensional control. The alkaline quencher can be an organic amine compound, such as triethanolamine (TEA) or triisopropanolamine (TIPA), and its amount can be 0.1wt%-2wt% of the total mass of the solid components.

[0069] Furthermore, the additive can be a leveling agent (or surfactant). In the coating process of thick films with high solid content and high viscosity, the leveling agent helps to reduce the surface tension of the solution, improve its spreadability on the substrate, and reduce defects such as streaks and comet tails that may occur during the coating process, thereby obtaining a film layer with a smoother surface and more uniform thickness. The leveling agent can be a fluorinated or silicone-containing surfactant, such as polyether-modified polydimethylsiloxane, fluoropolymers, or combinations thereof, and its amount can be 0.1wt%-1wt% of the total mass of the solid components.

[0070] Furthermore, the additive can be an adhesion promoter, and its amount can be 0.1wt%-1wt% of the total mass of the solid components. The adhesion promoter is preferably a compound containing silane groups, such as methacryloxypropyltrimethoxysilane, to enhance the interfacial bonding strength between the photoresist and the copper-clad substrate during development and electroplating.

[0071] Furthermore, the viscosity of the positive chemical amplification photoresist composition at 25°C is 500 cP-2000 cP. The viscosity can be adjusted by changing the type and solid content of the organic solvent, thereby adapting to the process requirements of high-speed single spin coating.

[0072] Another specific embodiment of the present invention provides a method for preparing a positive chemical amplification photoresist composition, which includes the following steps: mixing at least acrylic resin, photoacid generator and organic solvent in a certain proportion to obtain a positive chemical amplification photoresist composition.

[0073] Another specific embodiment of the present invention provides a micro-pattern structure, the raw materials of which include at least a positive chemical amplification photoresist composition.

[0074] Specifically, a uniform film layer with a thickness of 50μm-80μm is formed on a substrate using a positive chemical amplification photoresist composition. After exposure, post-exposure baking (PEB), and alkaline development, the aspect ratio of the obtained micro-pattern is not less than 6:1, and the residual film rate in the unexposed area is not less than 90%.

[0075] Another specific embodiment of the present invention provides a method for preparing a micro-patterned structure, which specifically includes the following steps:

[0076] Step 1, coating process.

[0077] Specifically, a positive chemical amplification photoresist composition is spin-coated onto a substrate to form a photoresist layer. The substrate can be a copper-clad laminate, silicon wafer, glass substrate, polyimide film, etc. By adjusting the spin coater speed and time, and utilizing the high solids content of the composition, a uniform photoresist layer with a thickness of 50μm-80μm can be formed in a single spin coating process.

[0078] Step 2, softening and baking.

[0079] Specifically, a soft bake (or pre-bake) is performed on the coated substrate to remove most of the solvent from the photoresist layer, allowing it to solidify into a stable film and enhancing its adhesion to the substrate. The soft bake can be performed on a hot plate at a temperature of 120℃-140℃ for 2-5 minutes. The baking temperature and time need to be precisely controlled to ensure sufficient solvent evaporation without thermal decomposition of the PAG. Specifically, the residual solvent content in the photoresist should be kept below 5wt% to minimize potential film shrinkage and stress during subsequent exposure and PEB steps.

[0080] Step 3, the exposure step.

[0081] Specifically, the photoresist layer after soft baking is selectively exposed using an ultraviolet light source through a photomask with a predetermined pattern. The wavelength of the exposure light source can be 300nm-450nm, for example, i-line (365nm). In the exposed area, PAG absorbs light energy and decomposes to produce strong acid. The exposure dose can be 200mJ / cm². 2 -600mJ / cm 2 The exposure dose is set to ensure that the effective exposure dose at the bottom of the photoresist layer is not less than 50% of that at the top, in order to achieve a vertical sidewall profile. For thick films, sufficient exposure energy is required to ensure that a sufficient photochemical reaction can also occur at the bottom of the photoresist layer.

[0082] Step 4, post-exposure baking.

[0083] Specifically, after exposure, the substrate undergoes post-exposure baking (PEB). In this step, the strong acid generated in the exposed area acts as a catalyst, initiating a deprotection reaction of numerous acid-labile groups on the acrylic resin under thermal drive. This step is crucial for achieving chemical scale-up. The PEB temperature can be 90℃-110℃, and the time can be 1-3 minutes. PEB conditions have a significant impact on the size and contour of the final pattern. By optimizing the temperature and time to control the acid diffusion length (Ld) in the exposed area within the range of 50nm to 150nm, a balance between sensitivity and pattern resolution can be achieved.

[0084] Step 5, Development Step.

[0085] Specifically, an alkaline developer is used to develop the baked substrate. In the exposed areas, the resin becomes soluble in the alkaline developer due to the deprotection reaction and is thus dissolved and removed; while in the unexposed areas, the resin structure remains unchanged and remains insoluble, thus being retained to form the desired photoresist pattern. The alkaline developer can be a metal ion-free developer, such as a 2wt%-3wt% aqueous solution of tetramethylammonium hydroxide (TMAH), specifically 2.38wt%. The development time can be 1-3 minutes, and the development process uses spraying or immersion, with the solution temperature maintained at 20℃-25℃ to ensure uniform thick film development rate. After development, a high-quality micro-pattern with steep sidewalls and an aspect ratio of not less than 6:1 can be obtained.

[0086] Furthermore, the micro-patterning preparation method of the present invention can be used to form thick-film copper conductive lines and printed circuit boards containing such lines (L / S≤10μm / 10μm). Specifically, after completing steps 1-5, steps 6 and 7 are performed. Step 6 is: electroplating, performing pattern electroplating on the substrate with micro-patterns, depositing a metal layer in the grooves of the micro-patterns to form conductive lines.

[0087] Specifically, a substrate with a photoresist pattern is used as the cathode, and electroplating is performed in a copper plating solution. This solution can be commercially available or prepared using conventional methods. The plating process can be either pulse plating or direct current plating. Copper is selectively deposited on the exposed substrate areas defined by the photoresist pattern, forming a copper plating layer. The current density of the electroplating process can be 1 A / dm³. 2 -5A / dm 2 The plating bath temperature can be 20℃-30℃. The electroplating time is determined according to the required copper layer thickness (40μm-60μm).

[0088] Step 7, the peeling step.

[0089] Specifically, after electroplating, the remaining photoresist pattern can be removed using a suitable solvent (such as acetone or a special stripping solution), ultimately leaving the required thick-film copper conductive lines on the substrate to produce a printed circuit board. The line thickness is 50μm-80μm, and the line width / spacing is ≤10μm / 10μm.

[0090] The present invention will be further described in detail below with reference to specific embodiments.

[0091] Example 1

[0092] The preparation method of the positive chemical amplification photoresist composition in this embodiment is as follows:

[0093] (1) Add methyl methacrylate (40g), glycidyl methacrylate (28.4g) and tert-butyl methacrylate (56.8g) to a nitrogen-filled reactor, then add 125g of methanol and 5.5g of azobisisobutyronitrile. After stirring evenly, start heating. Set the heating temperature to 75℃. After the reflux in the reactor begins to stabilize, start the reaction for 14 hours, then stop the reaction and cool the reaction solution to room temperature.

[0094] (2) Add the reaction solution to pure water, precipitate out, filter, and add the filtered solid to an equal mass of tetrahydrofuran and stir until completely dissolved.

[0095] (3) After repeating step (2) three times, a solid precipitate is obtained.

[0096] (4) The solid precipitate was placed in a vacuum oven and dried at low temperature for 48 hours to obtain the desired acrylic resin.

[0097] (5) Take 100g of acrylic resin and add it to PGMEA. Stir at 30°C under a nitrogen atmosphere until the acrylic resin is completely dissolved to form a uniform resin mother liquor.

[0098] (6) Add 1g of diphenyliodonium hexafluoroantimonate to the resin mother liquor, stir until all solid components are completely dissolved to form a homogeneous solution with a solid content of 50wt%, and filter to obtain a positive chemical amplification photoresist composition.

[0099] Examples 2-8

[0100] The preparation methods of the positive chemical amplification photoresist compositions in Examples 2-8 are basically the same as those in Example 1, except that the types and amounts of raw materials used are different, as shown in Tables 1 and 2.

[0101] Table 1 Raw materials used in acrylic resin

[0102]

[0103] Table 2 Raw materials used in the positive chemical amplification photoresist compositions of each embodiment

[0104]

[0105] Comparative Example 1

[0106] The preparation method of the positive chemical amplification photoresist composition in this comparative example is as follows:

[0107] (1) Add methyl methacrylate (40g), glycidyl methacrylate (28.4g) and methoxyethyl methacrylate (58g) to a nitrogen-filled reactor, then add 125g of methanol and 5.5g of azobisisobutyronitrile. After stirring evenly, start heating. Set the heating temperature to 75℃. After the reflux in the reactor begins to stabilize, start the reaction for 14 hours, then stop the reaction and cool the reaction solution to room temperature.

[0108] (2) Add the reaction solution to pure water, precipitate out, filter, and add the filtered solid to an equal mass of tetrahydrofuran and stir until completely dissolved.

[0109] (3) After repeating step (2) three times, a solid precipitate is obtained.

[0110] (4) The solid precipitate was placed in a vacuum oven and dried at low temperature for 48 hours to obtain the desired acrylic resin.

[0111] (5) Take 100g of acrylic resin and add it to PGMEA. Stir at 30°C under a nitrogen atmosphere until the acrylic resin is completely dissolved to form a uniform resin mother liquor.

[0112] (6) Add 1g of diphenyliodonium hexafluoroantimonate to the resin mother liquor, stir until all solid components are completely dissolved to form a homogeneous solution with a solid content of 50wt%, and filter to obtain a positive chemical amplification photoresist composition.

[0113] Comparative Examples 2-3

[0114] The preparation methods of the positive chemical amplification photoresist compositions in Comparative Examples 2-3 are basically the same as those in Comparative Example 1, except that the types and amounts of raw materials used are different, as shown in Tables 3 and 4.

[0115] Table 3 Raw materials used in acrylic resins

[0116]

[0117] Table 4. Raw materials used in the positive chemical amplification photoresist compositions of each comparative example.

[0118]

[0119] Micro-patterned structures were prepared using the positive chemical amplification photoresist compositions from each example and comparative example. The preparation methods are as follows:

[0120] (1) Take a silicon wafer substrate and apply a positive chemical amplification photoresist composition onto the silicon wafer substrate to form a film layer with a thickness of 80 μm.

[0121] (2) The coated substrate is softened at 130°C for 3 minutes.

[0122] (3) Expose the softened film layer with a mask bearing a predetermined precision pattern using i-line (365nm) exposure at an exposure dose of 300mJ / cm. 2 .

[0123] (4) After exposure, bake at 100℃ for 3 minutes.

[0124] (5) Develop the microstructure using a 2.38 wt% tetramethylammonium hydroxide (TMAH) aqueous solution for 180 seconds.

[0125] Observe the micropatterned structures prepared using the positive chemical amplification photoresist compositions in each example and comparative example. The micropatterned structure in Example 1 is as follows: Figure 1 As shown, the micro-graphic structure in Comparative Example 1 is as follows: Figure 2 As shown, observation reveals that the film thickness of the micro-patterns in the embodiment reaches 80 μm, the pore size meets the requirement of 15-20 μm, no "T-topping" structure is observed at the top, and no "footing" is generated in the unexposed areas. However, the microstructures in the comparative examples exhibit top T-topping and bottom footing, and some of the comparative examples have problems with incomplete development, which does not meet the requirements.

[0126] In summary, the positive chemical amplification photoresist composition of this invention addresses the high efficiency and high quality requirements for patterning thick-film photoresists in the 50μm to 80μm range in high-precision semiconductor packaging, microelectromechanical systems (MEMS), and high-density printed circuit boards (HD-PCB) manufacturing by synergistically optimizing the polymerization system, the content of acid stabilizing groups, photoacid generators, and solvent rheological properties.

[0127] The compositions and related methods disclosed in this invention focus on overcoming the technical challenges of traditional thick-film photoresists in terms of single-coat application, exposure penetration depth, and high aspect ratio pattern sidewall perpendicularity. The compositions possess optimized rheological properties and high solids content, enabling the stable formation of uniform films with thicknesses of 50 μm to 80 μm on substrates such as copper-clad laminates, silicon wafers, or glass substrates via a single spin-coating process.

[0128] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from the spirit or essential characteristics of this disclosure. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this disclosure.

[0129] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A positive chemical amplification photoresist composition, characterized in that, The positive chemical amplification photoresist composition includes at least the following components: acrylic resin containing acid-indestabilized groups; photoacid-generating agent; and organic solvent.

2. The positive chemical amplification photoresist composition according to claim 1, characterized in that, The raw materials of the acrylic resin include monomer A, which contains acid-instable groups; monomer B, which contains ester groups; and monomer C, which contains cyclic structural groups. Based on the total molar amount of the acrylic resin, the molar percentage of monomer A is 20%-40%, the molar percentage of monomer B is 40%-60%, and the molar percentage of monomer C is 5%-20%.

3. The positive chemical amplification photoresist composition according to claim 2, characterized in that, The monomer A is at least one of tert-butyl methacrylate, cyclohexyl ethyl methacrylate, tetrahydrofuran methacrylate, tetrahydropyran methacrylate, and adamantyl methacrylate. The monomer B is methyl methacrylate; The monomer C is glycidyl methacrylate.

4. The positive chemical amplification photoresist composition according to claim 2, characterized in that, The acrylic resin is prepared as follows: Mix monomers A, B, and C, add solvent and initiator under a nitrogen atmosphere, heat to 70℃-80℃, react for 13-15 hours, and then cool to room temperature. The reaction solution was mixed with pure water to precipitate the precipitate, which was then filtered. The precipitate was dissolved in tetrahydrofuran, and then pure water was added again to precipitate the precipitate. This process was repeated several times to obtain the precipitate. The precipitate was dried to obtain acrylic resin.

5. The positive chemical amplification photoresist composition according to claim 1, characterized in that, The acrylic resin has a number-average molecular weight of 5,000-50,000, a weight-average molecular weight of 20,000-60,000, and a molecular weight distribution index of 1.5-2.

5.

6. The positive chemical amplification photoresist composition according to claim 1, characterized in that, The solid content of the positive chemical amplification photoresist composition is 30wt%-50wt%; and / or, The positive chemical amplification photoresist composition has a viscosity of 500 cP-2000 cP at 25°C.

7. The positive chemical amplification photoresist composition according to claim 1, characterized in that, The photoacid-producing agent is at least one of a sulfonium salt compound and an iodonium salt compound; and / or, Based on the solid components in the positive chemical amplification photoresist composition, the photoacid-generating agent accounts for 1wt%-5wt% by mass; and / or, The organic solvent is at least one of propylene glycol monomethyl ether acetate, γ-butyrolactone, and ethyl lactate.

8. The positive chemical amplification photoresist composition according to claim 1, characterized in that, The positive chemical amplification photoresist composition further includes at least one of an alkaline quencher, a leveling agent, and an adhesion promoter, wherein the alkaline quencher is an organic amine compound, the leveling agent is a fluorinated leveling agent and / or a silicon-containing leveling agent, and the adhesion promoter is a silane group compound. Based on the solid components in the positive chemical amplification photoresist composition, the alkaline quencher accounts for 0.1wt%-2wt% by mass, the leveling agent accounts for 0.1wt%-1wt% by mass, and the adhesion promoter accounts for 0.1wt%-1wt% by mass.

9. A method for preparing the positive chemical amplification photoresist composition according to claim 1, characterized in that, At least the acrylic resin, photoacid generator and organic solvent are mixed in the specified proportions to obtain a positive chemical amplification photoresist composition.

10. A micro-graphic structure, characterized in that, The raw materials for the micro-patterned structure include at least the positive chemical amplification photoresist composition as described in claim 1; The thickness of the micro-patterned structure is 50μm-80μm, the aspect ratio is greater than or equal to 6:1, and the residual film rate is greater than or equal to 90%.

11. A method for preparing the micro-patterned structure according to claim 10, characterized in that, The preparation method includes the following steps: Coating: A positive chemical amplification photoresist composition is coated onto a substrate to form a photoresist layer; Soft baking; exposure; Baking after exposure; Development yields micro-patterned structures.

12. The method for preparing a micro-patterned structure according to claim 11, characterized in that, In the coating step, the coating thickness is 50μm-80μm; and / or, In the softening step, the temperature is 120℃-140℃, and the time is 2min-5min; and / or, In the exposure step, the wavelength of the exposure light source is 300nm-450nm, and the exposure dose is 200mJ / cm². 2 -600mJ / cm 2 ; and / or, In the post-exposure baking step, the temperature is 90℃-110℃, and the time is 1min-3min; and / or, In the developing step, the developing solution is an aqueous solution of 2wt%-3wt% tetramethylammonium hydroxide, and the time is 1min-3min.

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