Chemically amplified positive photoresist and its application
By using a specific combination of polymer resins and photoacid generators, the transparency of chemically amplified positive photoresist to short-wavelength light sources is enhanced, solving the problem of low resolution in existing technologies and achieving high-resolution and high-contrast photolithographic patterns.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUZHOU KAIXIN SEMICONDUCTOR MATERIALS CO LTD
- Filing Date
- 2024-12-31
- Publication Date
- 2026-05-29
Smart Images
Figure QLYQS_1 
Figure QLYQS_2 
Figure QLYQS_3
Abstract
Description
Technical Field
[0001] This application relates to the field of photolithography materials technology, and in particular to a chemically amplified positive photoresist and its applications. Background Technology
[0002] Positive photoresist belongs to the field of advanced semiconductor manufacturing materials technology and is widely used in the fabrication of micro-patterned circuits in the optoelectronic information industry. It is a key material in the electronics manufacturing field. After exposure, development, etching and other processes, positive photoresist can transfer the pattern on the photomask onto the substrate to form a geometric pattern that completely corresponds to the photomask.
[0003] Positive photoresists can be divided into two categories based on their chemical principles: chemical amplification and non-chemical amplification. Chemical amplification positive photoresists include polymer resins, photoacid generators, additives, and solvents. The principle behind this is that the acid generated by the photoacid generator under light irradiation catalyzes the chemical change of the acid-sensitive groups on the polymer resin, thereby amplifying the performance of the positive photoresist. This type of photoresist is widely used in the field of short-wavelength lithography.
[0004] Currently, the polymer resin commonly used in chemically amplified positive photoresists is usually poly(p-hydroxystyrene) resin. However, this type of chemically amplified positive photoresist has strong absorption for lower wavelength light sources, resulting in lower resolution (i.e., poor resolution) in processes using such light sources. Summary of the Invention
[0005] This application provides a chemically amplified positive photoresist and its application to solve the technical problems existing in related technologies. It includes the following technical solutions:
[0006] In a first aspect, this application provides a chemically amplified positive photoresist, the chemically amplified positive photoresist comprising the following components in weight percentages: 5%-20% polymer resin, 0.05%-1% photoacid generator, 0.01%-0.05% alkaline quencher, 100ppm-1000ppm leveling agent, and the balance being solvent; wherein the polymer resin comprises a first copolymer and a second copolymer, the polymer monomers of the first copolymer comprising: polycycloalkyl-protected methacrylate, long-chain alkyl-protected methacrylate, α-oxygen-containing group-protected methacrylate, and methacrylic acid, and the polymer monomers of the second copolymer comprising hydroxystyrene, styrene, and tert-butyl acrylate.
[0007] In some possible embodiments, the polycyclic protected methacrylate is selected from at least one of the following compounds:
[0008]
[0009] The long-chain alkyl-protected methacrylate is selected from at least one of the following compounds:
[0010]
[0011] The α-oxygen-containing protected methacrylate is selected from at least one of the following compounds:
[0012]
[0013] In some possible embodiments, the polymeric monomers of the first copolymer satisfy the following molar percentages: polycyclic alkyl-protected methacrylate compounds, 10% to 30%; long-chain alkyl-protected methacrylate compounds, 5% to 25%; α-oxygen-containing methacrylate compounds, 30% to 70%; and methacrylic acid, 1% to 15%.
[0014] In some possible implementations, the mass ratio of the first copolymer to the second copolymer is 1.5-9:1.
[0015] In some possible implementations, the first copolymer satisfies at least one of the following physical properties: a weight-average molecular weight of 8K-15K and a molecular weight distribution coefficient (PDI) < 3.
[0016] In some possible embodiments, the polymeric monomers of the second copolymer satisfy the following molar percentages: hydroxystyrene compound, 60%–70%; styrene compound, 10%–30%; tert-butyl acrylate compound, 10%–30%.
[0017] In some possible implementations, the photoacid generator is a nonionic photoacid generator.
[0018] In some possible embodiments, the photoacid-producing agent comprises a first nonionic photoacid-producing agent and a second nonionic photoacid-producing agent; the first nonionic photoacid-producing agent is selected from at least one of the following compounds:
[0019]
[0020]
[0021] The structure of the second nonionic photoacid-generating agent is shown below:
[0022]
[0023] Wherein, R is selected from one of the following structures:
[0024]
[0025] In some possible implementations, the alkaline quencher is selected from aliphatic amine quenchers.
[0026] In some possible embodiments, the aliphatic amine quencher is selected from at least one of monoalkylamines, dialkylamines, trialkylamines, alkanolamines, and tetramethylammonium hydroxide.
[0027] In a second aspect, this application provides a method for preparing a chemically amplified positive photoresist as described in the first aspect of this application, comprising the following steps: Step 1: mixing a first copolymer and a second copolymer to obtain a polymer resin. The polymer monomers of the first copolymer may include, for example, polycyclic alkyl-protected methacrylates, long-chain alkyl-protected methacrylates, α-oxygen-containing group-protected methacrylates, and methacrylic acid; the polymer monomers of the second copolymer may include, for example, hydroxystyrene, styrene, and tert-butyl acrylate; Step 2: mixing the following components in mass percentages: 5%-20% polymer resin, 0.05%-1% photoacid generator, 0.01%-0.05% alkaline quencher, 100ppm-1000ppm leveling agent, and solvent to make up the mass percentage, to obtain the chemically amplified positive photoresist as described in this application.
[0028] In a third aspect, this application provides an application of the chemically amplified positive photoresist as described in the first aspect of this application in a photolithography process, comprising the following steps: Step 1: uniformly applying the chemically amplified positive photoresist provided in this application onto a surface-modified silicon wafer; Step 2: performing soft baking on the silicon wafer coated with the chemically amplified positive photoresist; Step 3: exposing the soft-baked silicon wafer using a projection exposure machine; Step 4: performing post-baking on the exposed silicon wafer; Step 5: developing the post-baked silicon wafer using a developing solution.
[0029] The beneficial effects of the technical solution provided in this application include at least the following:
[0030] The chemically amplified positive photoresist provided in this application embodiment uses a combination of a first copolymer and a second copolymer as its polymer resin. The first copolymer's monomers include: polycyclic alkyl-protected methacrylate, long-chain alkyl-protected methacrylate, α-oxygen-containing group-protected methacrylate, and methacrylic acid, making the first copolymer a polyacrylate resin. The second copolymer's monomers include hydroxystyrene, styrene, and tert-butyl acrylate, making the second copolymer a poly(p-hydroxystyrene) resin. The combined effect of these two monomers, while meeting the basic performance requirements of the chemically amplified positive photoresist, effectively utilizes the optical property of polyacrylate resin's transparency to short-wavelength light sources, enhancing the transparency of the chemically amplified positive photoresist to short-wavelength light sources. This improves the resolution of the chemically amplified positive photoresist during processing under such light sources, achieving good resolution, high contrast, and low linewidth roughness in the photolithographic pattern. Detailed Implementation
[0031] In view of this, this application discloses a chemically amplified positive photoresist and its application. A series of acrylic resins are designed, utilizing the optical properties of acrylic resins that are transparent to short-wavelength light sources. By using acrylic resin and poly(p-hydroxystyrene) resin in combination as chemically amplified positive photoresist resins, along with other additives, the raw materials of the chemically amplified positive photoresist are organically combined, resulting in a pattern with low line width roughness, good resolution, and high contrast after development.
[0032] The first aspect of this application discloses a chemically amplified positive photoresist, which comprises the following components in weight percentage:
[0033] Polymer resin 5%-20%, photoacid generator 0.05%-1%, alkaline quencher 0.01%-0.05%, leveling agent 100ppm-1000ppm, solvent as balance.
[0034] The polymer resin may include, for example, a first copolymer and a second copolymer. The polymer monomers of the first copolymer may include, for example, polycyclic alkyl-protected methacrylates, long-chain alkyl-protected methacrylates, α-oxygen-containing group-protected methacrylates, and methacrylic acid. The polymer monomers of the second copolymer may include, for example, hydroxystyrene, styrene, and tert-butyl acrylate.
[0035] The chemically amplified positive photoresist provided in this application embodiment uses a combination of a first copolymer and a second copolymer as its polymer resin. The first copolymer's monomers include: polycyclic alkyl-protected methacrylate, long-chain alkyl-protected methacrylate, α-oxygen-containing group-protected methacrylate, and methacrylic acid, making the first copolymer a polyacrylate resin. The second copolymer's monomers include hydroxystyrene, styrene, and tert-butyl acrylate, making the second copolymer a poly(p-hydroxystyrene) resin. The combined effect of these two monomers, while meeting the basic performance requirements of the chemically amplified positive photoresist, effectively utilizes the optical property of polyacrylate resin's transparency to short-wavelength light sources, enhancing the transparency of the chemically amplified positive photoresist to short-wavelength light sources. This improves the resolution of the chemically amplified positive photoresist during processing under such light sources, achieving good resolution, high contrast, and low linewidth roughness in the photolithographic pattern.
[0036] In some embodiments, polycyclic alkyl-protected methacrylates may be selected from at least one of the following compounds:
[0037]
[0038]
[0039] Long-chain alkyl-protected methacrylates may be selected from at least one of the following compounds:
[0040]
[0041] α-Oxygen-containing protected methacrylates may be selected from at least one of the following compounds:
[0042]
[0043] In some embodiments, the polymeric monomers of the first copolymer may, for example, satisfy the following molar percentages: The molar percentage of polycycloalkyl-protected methacrylate compounds may, for example, include 10% to 30%, specifically including but not limited to 10%, 12%, 14%, 16%, 18%, 20%, 30%, etc.; The molar percentage of long-chain alkyl-protected methacrylate compounds may, for example, include 5% to 25%, specifically including but not limited to 5%, 7%, 9%, 11%, 13%, 15%, 17%, 19%, 20%, 25%, etc.; The molar percentage of α-oxygen-containing methacrylate compounds may, for example, include 30% to 70%, specifically including but not limited to 30%, 40%, 50%, 55%, 60%, 65%, 70%, etc.; The molar percentage of methacrylic acid may, for example, include 1% to 15%, specifically including but not limited to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, etc.
[0044] In some embodiments, the first copolymer may satisfy at least one of the following physical properties: a weight-average molecular weight of 8K-15K, specifically 8K, 9K, 10K, 11K, 12K, 13K, 14K, 15K, or other values within the above range; and a molecular weight distribution coefficient (PDI) < 3, specifically 2.8, 2.6, 2.4, 2.2, 2, 1.8, 1.6, 1.4, 1.2, 1, or other values within the above range.
[0045] In one embodiment, the polymeric monomers of the first copolymer may include, for example, isobornyl methacrylate, n-butyl methacrylate, γ-butyrolactone methacrylate, and methacrylic acid; the molar percentage of the polymeric monomers of the first copolymer may include, for example, 15% isobornyl methacrylate, 10% n-butyl methacrylate, 65% γ-butyrolactone methacrylate, and 10% methacrylic acid; the weight-average molecular weight of the first copolymer may be, for example, 10501 g / mol; and the molecular weight distribution coefficient (PDI) of the first copolymer may be, for example, 2.22.
[0046] In some embodiments, the polymeric monomers of the second copolymer may satisfy the following molar percentages, for example: the molar percentage of the hydroxystyrene compound may be 60% to 70%, specifically 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, etc., or other values within the above range; the molar percentage of the styrene compound may be 10% to 30%, specifically 10%, 15%, 20%, 25%, 30%, etc., or other values within the above range; the molar percentage of the tert-butyl acrylate compound may be 10% to 30%, specifically 10%, 15%, 20%, 25%, 30%, etc., or other values within the above range.
[0047] In some embodiments, the second copolymer may satisfy at least one of the following physical properties: a weight-average molecular weight of 8K-15K, specifically 8K, 9K, 10K, 11K, 12K, 13K, 14K, 15K, or other values within the above range; and a molecular weight distribution coefficient (PDI) < 3, specifically 2.8, 2.6, 2.4, 2.2, 2, 1.8, 1.6, 1.4, 1.2, 1, or other values within the above range.
[0048] In one embodiment, the monomers of the second copolymer may include, for example, p-hydroxystyrene, styrene, and tert-butyl acrylate; the molar percentage of the monomers of the second copolymer may include, for example, 15% p-hydroxystyrene, 65% styrene, and 20% tert-butyl acrylate; the weight-average molecular weight of the second copolymer may be, for example, 11000 g / mol; and the molecular weight distribution coefficient (PDI) of the first copolymer may be, for example, 1.81.
[0049] In some embodiments, the mass ratio of the first copolymer and the second copolymer of the polymer resin can be, for example, 1.5-9:1, specifically 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 2.5:1, 1.5:1, or other conditions within the above range.
[0050] In some embodiments, the photoacid generator may include, for example, a first nonionic photoacid generator and a second nonionic photoacid generator. The mass fraction of the first nonionic photoacid generator may include, for example, 10%-90%, specifically, but not limited to, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, etc.; the mass fraction of the second nonionic photoacid generator may include, for example, 10%-90%, specifically, but not limited to, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, etc. By using two different nonionic photoacid generators, the chemically amplified positive photoresist can generate acids with different structures after exposure. While maintaining high exposure sensitivity, it can also shorten the diffusion distance of the photoacid, thereby improving the resolution of the chemically amplified positive photoresist.
[0051] In some embodiments, the first nonionic photoacid generator may be selected from at least one of the following compounds:
[0052]
[0053]
[0054] In some embodiments, the structure of the second nonionic photoacid generator is shown below:
[0055]
[0056] R can be selected from one of the following structures:
[0057]
[0058] In some embodiments, the alkaline quencher may be selected from aliphatic amine quenchers; further, the aliphatic amine quencher may be selected from at least one of monoalkylamines, dialkylamines, trialkylamines, alkanolamines, and tetramethylammonium hydroxide; even further, the alkaline quencher may be selected from aliphatic amine quenchers with 12 or fewer carbon atoms. In some embodiments, monoalkylamines may include, but are not limited to, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and n-decylamine; dialkylamines may include, but are not limited to, diethylamine, di-n-propylamine, di-n-heptylamine, di-n-octylamine, and dicyclohexylamine; trialkylamines may include, but are not limited to, trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, and tri-n-dodecylamine; and alkanolamines may include, but are not limited to, diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, and tri-n-octanolamine.
[0059] In some embodiments, the leveling agent may be selected from at least one of 3M fluorocarbon surfactant FC-4430 and Troysol S366.
[0060] In some embodiments, the solvent may be selected from at least one of propylene glycol methyl ether acetate, propylene glycol methyl ether, ethyl lactate, anisole, propylene glycol monoacetate, propylene glycol monoethyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol methyl ethyl ether, butyl acetate, neopentyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, diacetone alcohol, or γ-butyrolactone.
[0061] A second aspect of this application provides a method for preparing the chemically amplified positive photoresist as described above, comprising the following steps:
[0062] Step 1: Mix the first copolymer and the second copolymer to obtain a polymer resin. The monomers of the first copolymer may include, for example, polycyclic alkyl-protected methacrylates, long-chain alkyl-protected methacrylates, α-oxygen-containing group-protected methacrylates, and methacrylic acid. The monomers of the second copolymer may include, for example, hydroxystyrene, styrene, and tert-butyl acrylate.
[0063] In some embodiments, the preparation process of the first copolymer may include, for example, the following steps: (1) dissolving isobornyl methacrylate, n-butyl methacrylate, γ-butyrolactone methacrylate, methacrylic acid, and azobisisobutyronitrile in propylene glycol methyl ether acetate at room temperature to obtain a first mixed solution. (2) heating the first mixed solution to 70°C and reacting for 8 hours under a nitrogen atmosphere. (3) cooling the reacted first mixed solution to room temperature and precipitating the first mixed solution after cooling to room temperature using the methanol precipitation method, washing and drying the obtained precipitate to obtain a solid sample of the first copolymer.
[0064] In some embodiments, the first mixed solution may include, for example, 33.35 g isobornyl methacrylate, 14.22 g n-butyl acrylate, 110.61 g γ-butyrolactone methacrylate, 8.61 g methacrylic acid, 3.5 g azobisisobutyronitrile and 70 g propylene glycol methyl ether acetate.
[0065] In some embodiments, the preparation process of the second copolymer may include the following steps: (1) Take a 500 mL four-necked flask, continuously introduce dry N2, turn on the stirrer, add 200 g of dry tetrahydrofuran solvent to the reaction flask using a peristaltic pump, and then cool the reaction flask using a liquid nitrogen / ethanol bath. (2) When the temperature drops to -40°C, use a syringe to add 0.9 mL of n-butyllithium hexane solution (concentration of 1.3 M) to the reaction flask, continue to cool to -70°C to -80°C, and use a peristaltic pump to add 67.7 g of styrene, 18 g of p-hydroxystyrene, and 25.63 g of tert-butyl acrylate to the reaction flask at a flow rate of 60 drops / min using a 10 mm diameter feeding tube to obtain the second mixed solution. (3) Maintain the temperature at -70°C to -80°C, continue the reaction for 1 h, and then add deoxygenated methanol to the reaction flask to terminate the reaction. (4) The second mixed solution after the termination reaction was precipitated using methanol precipitation. The precipitate was washed and dried to obtain the protected polymer of the second copolymer. (5) The protected polymer was deprotected using hydrobromic acid with acetone as solvent. The deprotected polymer was then precipitated with water, filtered, and dried to obtain a monodisperse solid sample of the second copolymer.
[0066] Step 2: Mix the following components in the indicated mass percentages: 5%-20% polymer resin, 0.05%-1% photoacid generator, 0.01%-0.05% alkaline quencher, 100ppm-1000ppm leveling agent, and solvent to make up the mass percentages to obtain the chemically amplified positive photoresist described in this application.
[0067] In some embodiments, the chemically amplified positive photoresist obtained in step two can also be filtered. For example, it can be filtered using a fluoropolymer filter with a pore size of 0.2 μm.
[0068] A third aspect of this application provides the application of the chemically amplified positive photoresist described above in a photolithography process, comprising the following steps:
[0069] Step 1: Apply the chemically amplified positive photoresist provided in this application uniformly onto a substrate, such as a surface-modified silicon wafer.
[0070] Step 2: Perform soft baking on the silicon wafer coated with chemically amplified positive photoresist.
[0071] In some embodiments, the softening temperature may include, for example, 105°C-115°C, and more particularly, 110°C; the softening time may include, for example, 80s-100s, and more particularly, 90s.
[0072] Step 3: Expose the softened silicon wafer using a projection exposure machine.
[0073] Step 4: Post-bake the exposed silicon wafer.
[0074] In some embodiments, the temperature of the post-baking process may include, for example, 95°C-105°C, and more specifically, 100°C; the time of the post-baking process may include, for example, 115s-125s, and more specifically, 120s.
[0075] Step 5: Develop the post-baked silicon wafer using a developing solution.
[0076] The chemically amplified positive photoresist provided in this application embodiment is suitable for exposure under short-wavelength light sources, such as 193nm wavelength and shorter wavelength light sources, while avoiding absorption under such light sources, thus making its process resolution higher under such light sources.
[0077] In some embodiments, the developer may include, for example, a 2.38% aqueous solution of tetramethylammonium hydroxide.
[0078] Exemplary embodiments of the present invention will now be described in more detail. While exemplary embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with techniques or conditions described in the literature in the art or according to product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.
[0079] Example 1
[0080] Example 1 provides a chemically amplified positive photoresist with the following formulation: 20 wt% polymer resin, 0.4 wt% photoacid generator, 0.008 wt% triethanolamine, 200 ppm FC-443, and the balance being propylene glycol methyl ether acetate. The composition of the polymer resin is shown in Table 1.
[0081] The first copolymer involved in the chemically amplified positive photoresist was prepared by the following method: 33.35 g of isobornyl methacrylate, 14.2 g of n-butyl methacrylate, 110.61 g of γ-butyrolactone methacrylate, 8.61 g of methacrylic acid, and 3.5 g of azobisisobutyronitrile were dissolved in 70 g of propylene glycol methyl ether acetate at room temperature to obtain a first mixed solution; then, the first mixed solution was heated to 70 °C and reacted for 8 h under a nitrogen atmosphere; then, the reacted first mixed solution was cooled to room temperature, and the first mixed solution cooled to room temperature was precipitated using the methanol precipitation method. The obtained precipitate was washed and dried to obtain the first copolymer, denoted as PA-1. The weight-average molecular weight of PA-1 was 10501 g / mol, and the PDI was 2.22.
[0082] The second copolymer involved in the chemically amplified positive photoresist was prepared using the following method: A 500mL four-necked flask was continuously purged with dry N2, and stirring was started. 200g of dry tetrahydrofuran solvent was added to the reaction flask using a peristaltic pump. The reaction flask was then cooled using a liquid nitrogen / ethanol bath. When the temperature dropped to -40℃, 0.9mL of a 1.3M hexane solution of n-butyllithium was added to the reaction flask using a syringe. The temperature was further lowered to -70℃ to -80℃. Using a peristaltic pump and a 10mm diameter feeding tube, 67.7g of styrene and 18g of p-hydroxystyrene were added dropwise to the reaction flask sequentially at a flow rate of 60 drops / min. 25.63 g of tert-butyl acrylate was used to obtain a second mixed solution. The temperature was then maintained at -70℃ to -80℃, and the reaction was continued for 1 hour. Then, methanol that had been deoxygenated was added to the reaction flask to terminate the reaction. The second mixed solution after the termination of the reaction was then precipitated using methanol precipitation. The precipitate was washed and dried to obtain the protected polymer of the second copolymer. Then, the protected polymer was deprotected using hydrobromic acid with acetone as solvent. The deprotected protected polymer was then precipitated with water, filtered, and dried to obtain a monodisperse second copolymer, denoted as PA-2. The weight average molecular weight of PA-2 was 11000 g / mol, and the PDI was 1.81.
[0083] Step 1: Mix the first copolymer and the second copolymer to obtain the polymer resin. The mass fractions of the first copolymer and the second copolymer in the polymer resin are detailed in Table 1.
[0084] Step 2: Dissolve 20 wt% polymer resin, 0.4 wt% photoacid generator, 0.008 wt% triethanolamine, and 200 ppm FC-443 in propylene glycol methyl ether acetate (the mass fraction of propylene glycol methyl ether acetate is the balance), and then filter using a 0.2 μm fluoropolymer filter to obtain a chemically amplified positive photoresist. See Table 1 for details of the types of photoacid generators.
[0085] Example 2
[0086] The difference between Example 2 and Example 1 is that the mass fractions of the first copolymer and the second copolymer in the polymer resin in step (1) are different (see Table 1 for details).
[0087] Example 3
[0088] The difference between Example 3 and Example 1 is that the mass fractions of the first copolymer and the second copolymer in the polymer resin in step (1) are different (see Table 1 for details).
[0089] Example 4
[0090] The difference between Example 4 and Example 1 is that the mass fractions of the first copolymer and the second copolymer in the polymer resin in step (1) are different (see Table 1 for details).
[0091] Example 5
[0092] The difference between Example 5 and Example 2 is that the proportion of photoacid-producing agent in step (2) is different (see Table 1 for details).
[0093] Example 6
[0094] The difference between Example 6 and Example 2 is that the proportion of photoacid-producing agent in step (2) is different (see Table 1 for details).
[0095] Comparative Example 1
[0096] The difference between Comparative Example 1 and Example 1 is that the mass fractions of the first copolymer and the second copolymer in the polymer resin in step (1) are different (see Table 1 for details).
[0097] Comparative Example 2
[0098] The difference between Comparative Example 2 and Example 1 is that the mass fractions of the first copolymer and the second copolymer in the polymer resin in step (1) are different (see Table 1 for details).
[0099] Comparative Example 3
[0100] The difference between Comparative Example 3 and Example 2 is that the type of photoacid-generating agent in step (2) is different (see Table 1 for details).
[0101] Comparative Example 4
[0102] The difference between Comparative Example 4 and Example 2 is that the type of photoacid-generating agent in step (2) is different (see Table 1 for details).
[0103] The composition of the polymer resin in the chemically amplified positive photoresist involved in the above embodiments and comparative examples can be found in Table 1.
[0104] Table 1
[0105]
[0106]
[0107]
[0108] Test case
[0109] Using the chemically amplified positive photoresist of Examples 1-6 and Comparative Examples 1-4 described above, photolithography was performed. The procedure is as follows: The chemically amplified positive photoresist was applied to a silicon wafer treated with hexamethyldisilazane and heated on a hot plate at 110°C for 90 seconds, resulting in a dried chemically amplified positive photoresist film thickness of 8 μm. Exposure was then performed using a projection exposure machine [“NSR-2005i9C”, manufactured by Nikon Crop., NA = 0.57, σ = 0.8] with an exposure wavelength of 365 (i-line), while gradually changing the exposure intensity. After exposure, the silicon wafer was heated on a hot plate at 100°C for 120 seconds, followed by single-wafer development using a 2.38% tetramethylammonium hydroxide aqueous solution.
[0110] The developed pattern was observed using a scanning electron microscope, and the following parameters were tested. The test results are shown in Table 2.
[0111] Effective photosensitivity: expressed as the exposure at a 1:1 ratio between 1.0μm lines and line spacing;
[0112] Resolution: The smallest size that distinguishes lines and gaps at the effective exposure level.
[0113] Table 2
[0114] NO. <![CDATA[Effective photosensitivity [mj / cm 2 > Resolution [μm] Example 1 41 2.2 Example 2 80 0.9 Example 3 129 1.4 Example 4 187 1.9 Example 5 102 1.1 Example 6 179 1.3 Comparative Example 1 40 3.5 Comparative Example 2 300 2.8 Comparative Example 3 90 2.1 Comparative Example 4 129 2.5
[0115] As shown in Table 2, when the polymer resin in the chemically amplified positive photoresist only includes the first copolymer, the resolution of the chemically amplified positive photoresist is poor; when the polymer resin in the chemically amplified positive photoresist only includes the second copolymer, both the effective photosensitivity and resolution of the chemically amplified positive photoresist are poor.
[0116] This application prepares chemically amplified positive photoresist by simultaneously using a first copolymer and a second copolymer, thereby achieving good line morphology while maintaining high resolution.
[0117] In the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" refers to two or more unless otherwise expressly defined.
[0118] The above description is only for the purpose of enabling those skilled in the art to understand the technical solution of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application shall be included within the scope of protection of this application.
Claims
1. A chemically amplified positive photoresist, characterized in that, The chemically amplified positive photoresist comprises the following components by weight percentage: The composition includes 5%-20% polymer resin, 0.05%-1% photoacid-producing agent, 0.01%-0.05% alkaline quencher, 100ppm-1000ppm leveling agent, and the balance being solvent; among which, The polymer resin includes a first copolymer and a second copolymer. The polymer monomers of the first copolymer include: polycyclic alkyl-protected methacrylate, long-chain alkyl-protected methacrylate, α-oxygen-containing group-protected methacrylate and methacrylic acid. The polymer monomers of the second copolymer include hydroxystyrene, styrene and tert-butyl acrylate. The monomers of the first copolymer satisfy the following molar percentages: Polycyclic-protected methacrylate compounds: 10%–30% Long-chain alkyl-protected methacrylate compounds: 5%–25% 30%-70% of methacrylate compounds are protected by α-oxygen groups. Methacrylic acid 1%-15%.
2. The chemically amplified positive photoresist according to claim 1, characterized in that, The polycyclic protected methacrylate is selected from at least one of the following compounds: 、 、 ； The long-chain alkyl-protected methacrylate is selected from at least one of the following compounds: 、 、 ； The α-oxygen-containing protected methacrylate is selected from at least one of the following compounds: 、 、 、 、 。 3. The chemically amplified positive photoresist according to claim 1, characterized in that, The mass ratio of the first copolymer to the second copolymer is 1.5-9:
1.
4. The chemically amplified positive photoresist according to claim 1, characterized in that, The first copolymer satisfies at least one of the following physical properties: weight-average molecular weight of 8K-15K and molecular weight distribution coefficient PDI < 3.
5. The chemically amplified positive photoresist according to claim 1, characterized in that, The polymeric monomers of the second copolymer satisfy the following molar percentages: Hydroxystyrene compounds account for 60%~70% Styrene compounds 10%~30% 10%-30% of tert-butyl acrylate compounds.
6. The chemically amplified positive photoresist according to claim 1, characterized in that, The photoacid-producing agent is a nonionic photoacid-producing agent.
7. The chemically amplified positive photoresist according to claim 6, characterized in that, The photo-induced acid-producing agent includes a first nonionic photo-induced acid-producing agent and a second nonionic photo-induced acid-producing agent; The first nonionic photoacid-generating agent is selected from at least one of the following compounds: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 ； The structure of the second nonionic photoacid-generating agent is shown below: Wherein, R is selected from one of the following structures: 、 、 、 。 8. The chemically amplified positive photoresist according to claim 1, characterized in that, The alkaline quencher is selected from aliphatic amine quenchers.
9. The chemically amplified positive photoresist according to claim 8, characterized in that, The aliphatic amine quencher is selected from at least one of monoalkylamines, dialkylamines, trialkylamines, alkanolamines, and tetramethylammonium hydroxide.
10. The application of the chemically amplified positive photoresist according to any one of claims 1-9 in photolithography processes.