A photosensitive polyimide precursor material with dual functions and its preparation method and application in photolithography

Abstract

The present invention provides a photosensitive polyimide precursor material with dual functions, a preparation method thereof and an application thereof in photolithography. The photosensitive polyimide precursor material with dual functions of the present invention is obtained by polymerizing a diamine and a dianhydride to obtain a precursor PAA polymer, and then esterifying the precursor with a compound having a hydrophobic and cross-linkable group. The polyimide material of the present invention can be used for positive photoresist and negative photoresist, and the polyimide material can be mixed with different photosensitizers, additives, etc. for coating, development and exposure to obtain a patterned polyimide film with good resolution.

Description

Technical Field

[0001] The invention relates to a photosensitive polyimide precursor material with dual functions, a preparation method thereof and application in photolithography, and belongs to the technical field of polymer photosensitive imaging. Background Art

[0002] Polyimide (PI) is a high-performance polymer material developed in the 1950s to meet the needs of aerospace for heat-resistant, lightweight and high-strength materials. It raises the use temperature of polymer materials to above 200°C. Polyimide monomers are abundant in source and have diverse synthetic routes. They show excellent structural and performance designability and flexible molding and processing. They have been widely used in many fields such as power and electrical, printed circuits, new displays and energy conversion. In the early semiconductor industry, the patterning of polyimide was achieved with the help of photoresist, that is, a layer of photoresist was coated on the surface of polyimide, and after it was patterned by photolithography, the underlying polyimide was treated by chemical etching and other methods, so that the pattern of the photoresist was transferred to the polyimide layer. In order to simplify the patterning process of polyimide, researchers gave polyimide photosensitivity, that is, synthetic photosensitive polyimide (PSPI), and used photolithography technology to directly make the pattern on the photosensitive polyimide layer to achieve its self-patterning. Therefore, photosensitive polyimide has the functions of both photoresist and dielectric insulation layer.

[0003] There are two types of PSPI. Most commercially available PSPI are prepared from polyamic acid (PAA): one is negative PSPI, which has pendant and photosensitive cross-linking groups on the main chain. The polymer is cross-linked in the exposed area and is insoluble in the developer, while the unexposed area is not cross-linked and is dissolved in the developer to form a pattern; the other type is positive PSPI. Due to the high acidity of carboxylic acid in PAA, the dissolution rate of PAA in tetramethylammonium hydroxide (TMAH) aqueous solution is too high, and it is impossible to obtain sufficient dissolution contrast between the unexposed area and the exposed area. This requires the introduction of hydrophobic groups in the PAA polymer to achieve high dissolution contrast (DC). The introduction of hydrophobic structures (such as aromatic groups and fluorine-containing groups) in the PAA polymer is beneficial to inhibit the dissolution of PAA in alkaline aqueous solutions, so that the synthesized PSPI has suitable photosensitivity and good image resolution.

[0004] If hydrophobic and cross-linkable groups are introduced into the PAA polymer, it can be cross-linked under light and has a hydrophobic effect, reducing the dissolution rate in the TMAH developer. The modified polyimide precursor can be mixed with a cross-linking agent and a photosensitive agent to form a negative photoresist, and can also be mixed with a DNQ-type photosensitive agent to form a positive photoresist, both of which can obtain patterns with good resolution. Therefore, the introduction of hydrophobic and cross-linkable groups into the PAA polymer can improve the performance of PAA and synthesize a polyimide precursor material with dual functions, which is of great significance in the field of photolithography. For this reason, the present invention is proposed. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a photosensitive polyimide precursor material with dual functions, a preparation method thereof, and an application thereof in photolithography. The photosensitive polyimide precursor material with dual functions of the present invention is obtained by polymerizing a diamine and a dianhydride to obtain a precursor PAA polymer, and then esterifying it with a compound having a hydrophobic and cross-linkable group. The polyimide precursor material of the present invention can be used for positive photoresist and negative photoresist, and is mixed with different photosensitizers, additives, etc. for coating, development, and exposure to obtain a patterned polyimide film with good resolution.

[0006] Terminology explanation:

[0007] Room temperature: has the well-known meaning in the art, referring to 25±5°C.

[0008] The technical solution of the present invention is as follows:

[0009] A photosensitive polyimide precursor material with dual functions is obtained by polymerizing diamine and dianhydride to obtain a precursor PAA polymer, which is then subjected to an esterification reaction with a compound having a hydrophobic and cross-linkable group.

[0010] Preferably according to the present invention, the diamine is 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP), 2,2-bis(3-amino-4-hydroxyphenyl)propane (BAP), 4,4'-diaminodiphenyl ether, 4,4'-diaminobiphenyl, p-phenylenediamine or m-phenylenediamine.

[0011] According to the preferred embodiment of the present invention, the dianhydride is 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), pyromellitic dianhydride, 4,4'-(hexafluoroisopropylene) diphthalic anhydride, 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride or 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride.

[0012] Preferably according to the present invention, the compound having a hydrophobic and cross-linkable group is acryloyl chloride, tert-butyl acrylate, methyl methacrylate, glycidyl methacrylate, methacryloyl chloride or p-hydroxystyrene; further preferably glycidyl methacrylate, methacryloyl chloride or p-hydroxystyrene.

[0013] According to the present invention, the method for preparing the above-mentioned photosensitive polyimide precursor material having dual functions comprises the following steps:

[0014] (1) under nitrogen protection, diamine and dianhydride are added to a solvent and reacted at room temperature to obtain a reaction solution A;

[0015] (2) Under nitrogen protection, a compound having a hydrophobic and cross-linkable group is added to the reaction solution A obtained in step (1) to react to obtain a reaction solution B; the reaction solution B is added to deionized water to precipitate, and the precipitate is filtered and dried to obtain a photosensitive polyimide precursor material having dual functions.

[0016] Preferably according to the present invention, the molar ratio of the diamine to the dianhydride in step (1) is 0.5 to 2:1.

[0017] Preferably according to the present invention, the solvent in step (1) is N-methylpyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide; the ratio of the volume of the solvent to the mass of the diamine is 5-10 mL:1 g.

[0018] According to a preferred embodiment of the present invention, the reaction time in step (1) is 5 to 24 hours, more preferably 10 to 15 hours.

[0019] Preferably according to the present invention, the molar ratio of the compound having a hydrophobic and cross-linkable group to the diamine in step (2) is 0.1 to 1.5:1, and more preferably 0.2 to 0.5:1.

[0020] Preferably according to the present invention, when the compound having a hydrophobic and cross-linkable group in step (2) is tert-butyl acrylate, methyl methacrylate, glycidyl methacrylate or p-hydroxystyrene, triphenylphosphine and 4-methoxyphenol are also added to the system; the molar ratio of the triphenylphosphine to the compound having a hydrophobic and cross-linkable group is 0.01 to 0.05:1, more preferably 0.02 to 0.03:1; the molar ratio of the 4-methoxyphenol to the compound having a hydrophobic and cross-linkable group is 0.005 to 0.02:1.

[0021] Preferably according to the present invention, when the compound having a hydrophobic and cross-linkable group in step (2) is acryloyl chloride or methacryloyl chloride, triethylamine is also added to the system; the molar ratio of the triethylamine to the compound having a hydrophobic and cross-linkable group is 1:1; the compound having a hydrophobic and cross-linkable group is added to the system at 0-5°C.

[0022] Preferably according to the present invention, when the compound having a hydrophobic and cross-linkable group in step (2) is tert-butyl acrylate, methyl methacrylate, glycidyl methacrylate or p-hydroxystyrene, the reaction temperature is 95-105°C; when the compound having a hydrophobic and cross-linkable group is acryloyl chloride or methacryloyl chloride, the reaction temperature is room temperature.

[0023] Preferably according to the present invention, the reaction time in step (2) is 8 to 12 hours.

[0024] Preferably, according to the present invention, the mass ratio of the reaction solution B to deionized water in step (2) is 1:15-30.

[0025] Preferably, according to the present invention, the drying in step (2) is vacuum drying at 40° C. for 24 hours.

[0026] According to the present invention, the above-mentioned bifunctional photosensitive polyimide precursor material is used in a positive photoresist system and a negative photoresist system.

[0027] The technical features and beneficial effects of the present invention are as follows:

[0028] 1. Since there are many kinds of raw materials diamine and dianhydride for synthesizing polyimide materials, and different diamines and dianhydrides have different physical and chemical properties for synthesizing imide materials. The present invention screened and obtained specific types of diamines and dianhydrides as the main materials for condensation through a large number of experiments, and then carried out esterification reaction with specific compounds having both hydrophobic effect and cross-linkable groups (such as "double bonds") to obtain a photosensitive polyimide precursor with bifunctionality, which can be used for both positive and negative resist preparation of resin materials. The bifunctionality of this resin material has certain innovation.

[0029] 2. The present invention obtains a polyimide precursor material by esterifying the carboxyl group (or phenolic hydroxyl group) in polyamic acid (PAA) with a hydrophobic and cross-linkable group. By esterifying polyamic acid and a small molecule with a hydrophobic and cross-linkable group, the generated polyimide precursor material has dual functionality, which is unique in concept and novel in method, and expands the concept for the application of polyimide materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1This is the H-NMR spectrum of the bifunctional photosensitive polyimide precursor material prepared in Example 1.

[0031] Figure 2 This is an infrared characterization diagram of the changes in functional groups of GMA and PAA before and after grafting GMA in Example 2.

[0032] Figure 3 This is an optical microscope photograph of the photoresist obtained in Experimental Example 1 after patterning.

[0033] Figure 4 This is an optical microscope photograph of the photoresist obtained in Experimental Example 2 after patterning. DETAILED DESCRIPTION

[0034] The present invention is further described below with reference to specific embodiments, but is not limited thereto.

[0035] Meanwhile, the experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0036] Example 1

[0037] A method for preparing a photosensitive polyimide precursor material with dual functions comprises the following steps:

[0038] Take 132g of NMP pre-dried with 4A molecular sieve for 24h in a three-necked flask, add 18.3g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP), stir until completely dissolved, add 14.7g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) under N2 and stirring conditions, and react at room temperature for 10h. Then add 0.0246g of 4-methoxyphenol, 0.1036g of triphenylphosphine and 2.808g of glycidyl methacrylate (GMA) to the three-necked flask, raise the temperature to 100℃ and react for 10h. After the reaction stopped, it was naturally cooled to room temperature, and the reaction solution was slowly poured into 2L of deionized water under stirring, and filtered. The solid product was washed three times with deionized water to obtain a white solid, which was vacuum dried at 40°C for 24 hours to obtain a bifunctional photosensitive polyimide precursor material in the form of white powder.

[0039] The nuclear magnetic hydrogen spectrum of the photosensitive polyimide precursor material with dual functions prepared in this example is as follows: Figure 1 As shown in the figure, the hydroxyl peak at 5.25ppm and the double bond peaks at 5.65ppm and 6.00ppm indicate the success of grafting. The grafting ratio was calculated by NMR, and the expected grafting rate of GMA was 10%, the actual grafting rate was 6%, and the grafting success rate was 60%.

[0040] Example 2

[0041] A method for preparing a photosensitive polyimide precursor material with dual functions comprises the following steps:

[0042] Take 110.4g of NMP pre-dried with 4A molecular sieve for 24h in a three-necked flask, add 12.9g of 2,2-bis(3-amino-4-hydroxyphenyl)propane (BAP), stir until completely dissolved, add 14.7g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) under N2 and stirring conditions, and react at room temperature for 10h. Then add 0.0861g of 4-methoxyphenol, 0.3626g of triphenylphosphine and 9.828g of glycidyl methacrylate (GMA) to the three-necked flask, raise the temperature to 100℃ and react for 10h. After the reaction stopped, it was naturally cooled to room temperature, and the reaction solution was slowly poured into 2L of deionized water under stirring, and filtered. The solid product was washed three times with deionized water to obtain a white solid, which was vacuum dried at 40°C for 24 hours to obtain a bifunctional photosensitive polyimide precursor material in the form of white powder.

[0043] The infrared spectrum of the bifunctional photosensitive polyimide precursor material prepared in this example is as follows: Figure 2 As shown, 3411cm -1 The carboxyl peak of the grafted nanostructured carbonyl group was significantly reduced, proving that the grafting was successful.

[0044] Example 3

[0045] A method for preparing a photosensitive polyimide precursor material with dual functions comprises the following steps:

[0046] Take 132g of NMP pre-dried with 4A molecular sieves for 24h in a three-necked flask, add 18.3g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP), stir until completely dissolved, add 14.7g, 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) under N2 and stirring conditions, and react at room temperature for 10h. Then lower the temperature to 5°C, add 2.0238g of triethylamine to the three-necked flask, and then drop 2.0906g of methacryloyl chloride for 15min. Raise the temperature to room temperature and react for 10h. After the reaction stops, pour the reaction solution into 2L of deionized water under stirring, filter, and wash the solid product with deionized water 3 times to obtain a white solid, which is vacuum dried at 40°C for 24h to obtain a photosensitive polyimide precursor material with dual functions, which is a white powder.

[0047] Test Example 1

[0048] A method for preparing a positive photoresist system based on a photosensitive polyimide precursor material having dual functions comprises the following steps:

[0049] Add 1.6 g of the bifunctional photosensitive polyimide precursor material prepared in Example 1 to 8 g of cyclopentanone, stir at room temperature until completely dissolved, add 0.4 g of photosensitizer PAC320, stir evenly at room temperature, and filter with a 0.22 μm polytetrafluoroethylene filter to obtain.

[0050] The obtained photoresist system was spin-coated on the surface of a two-inch silicon wafer, and the specific process flow was spin-coating, pre-baking, 365nm ultraviolet exposure, and development to obtain a silicon wafer coated with a pattern. The specific process parameters are shown in Table 1 below, and 0.238wt% tetramethylammonium hydroxide developer was used for development.

[0051] Table 1

[0052]

[0053] The optical microscope image of the obtained photoresist pattern is as follows Figure 3 As shown, the obtained photoresist surface is relatively smooth and the pattern is clear.

[0054] Test Example 2

[0055] A method for preparing a negative photoresist system based on a photosensitive polyimide precursor material having dual functions comprises the following steps:

[0056] To 8 g of cyclopentanone, add 1.3 g of the bifunctional photosensitive polyimide precursor material prepared in Example 1, and stir at room temperature until completely dissolved. Then, add 0.2 g of CA-60, 0.4 g of 59HW, 0.06 g of 3D, and 0.04 g of PB01 respectively, stir evenly at room temperature, and filter with a 0.22-micron polytetrafluoroethylene filter to obtain.

[0057] The obtained photoresist system was spin-coated on the surface of a two-inch silicon wafer, and the specific process flow was spin-coating, pre-baking, 365nm ultraviolet exposure, post-baking, and development to obtain a silicon wafer coated with a pattern. The specific process parameters are shown in Table 2 below, and a 2.38wt% tetramethylammonium hydroxide developer was used for development.

[0058] Table 2

[0059]

[0060] The optical microscope image of the obtained photoresist pattern is as follows Figure 4 As shown, the pattern is clear.

Claims

1. A photosensitive polyimide precursor material with dual functions, characterized in that: The photosensitive polyimide precursor material is obtained by polymerizing diamine and dianhydride to obtain a precursor PAA polymer, and then esterifying it with a compound having a hydrophobic and cross-linkable group; The diamine is 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane or 2,2-bis(3-amino-4-hydroxyphenyl)propane; The dianhydride is 3,3',4,4'-biphenyltetracarboxylic dianhydride; The compound having a hydrophobic and cross-linkable group is acryloyl chloride, tert-butyl acrylate, methyl methacrylate, glycidyl methacrylate, methacryloyl chloride or p-hydroxystyrene; the molar ratio of the compound having a hydrophobic and cross-linkable group to the diamine is 0.2-0.5:

1.

2. The method for preparing the bifunctional photosensitive polyimide precursor material according to claim 1, comprising the following steps: (1) under nitrogen protection, diamine and dianhydride are added to a solvent and reacted at room temperature to obtain a reaction solution A; (2) Under nitrogen protection, a compound having a hydrophobic and cross-linkable group is added to the reaction solution A obtained in step (1) to react to obtain a reaction solution B; the reaction solution B is added to deionized water to precipitate, and after filtering and drying, a photosensitive polyimide precursor material having dual functions is obtained.

3. The method for preparing a bifunctional photosensitive polyimide precursor material according to claim 2, characterized in that: The molar ratio of the diamine to the dianhydride in step (1) is 0.5 to 2:1; the solvent is N-methylpyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide, and the ratio of the volume of the solvent to the mass of the diamine is 5 to 10 mL: 1 g; and the reaction time is 5 to 24 h.

4. The method for preparing a bifunctional photosensitive polyimide precursor material according to claim 2, characterized in that: When the compound having a hydrophobic and cross-linkable group in step (2) is tert-butyl acrylate, methyl methacrylate, glycidyl methacrylate or p-hydroxystyrene, triphenylphosphine and 4-methoxyphenol are also added to the system; the molar ratio of the triphenylphosphine to the compound having a hydrophobic and cross-linkable group is 0.01 to 0.05:1; the molar ratio of the 4-methoxyphenol to the compound having a hydrophobic and cross-linkable group is 0.005 to 0.02:1; When the compound having a hydrophobic and cross-linkable group is acryloyl chloride or methacryloyl chloride, triethylamine is also added to the system; the molar ratio of the triethylamine to the compound having a hydrophobic and cross-linkable group is 1:1; the compound having a hydrophobic and cross-linkable group is added to the system at 0-5°C.

5. The method for preparing a bifunctional photosensitive polyimide precursor material according to claim 2, characterized in that: When the compound having a hydrophobic and cross-linkable group in step (2) is tert-butyl acrylate, methyl methacrylate, glycidyl methacrylate or p-hydroxystyrene, the reaction temperature is 95-105° C.; when the compound having a hydrophobic and cross-linkable group is acryloyl chloride or methacryloyl chloride, the reaction temperature is room temperature; The reaction time is 8 to 12 hours; the mass ratio of the reaction solution B to deionized water is 1:15 to 30; and the drying is vacuum drying at 40° C. for 24 hours.

6. Use of the bifunctional photosensitive polyimide precursor material according to claim 1 in a positive photoresist system and a negative photoresist system.

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