Photosensitive polyimide resin, polyimide composition and preparation method thereof

Abstract

The invention discloses photosensitive polyimide resin, a polyimide composition and a preparation method thereof. The photosensitive polyimide resin has a molecular structure as shown in a formula (1). According to the invention, an aminated hyperbranched polysiloxane unit with hydrophobic property is introduced into a polyimide molecule main chain to form an inter-molecular-chain micro-crosslinking structure, and the resolution of the photoresist is effectively improved and the thermal expansion coefficient of the patterned film is reduced through the crosslinking reaction of a photosensitive unit; the low polarity and hydrophobic characteristics of rich Si-O-Si units and CF3 units in hyperbranched polysiloxane can reduce the dielectric constant of the patterned film. The Si-O-Si network unit, the glass and the silicon wafer have better interfacial compatibility, so that stronger interfacial acting force is formed, and the bonding force between the photoresist and a substrate is improved. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of photoresist materials, and particularly relates to a photosensitive polyimide resin, a polyimide composition and a preparation method thereof. Background Art

[0002] Photosensitive polyimide (PSPI) is a type of polyimide that is sensitive to ultraviolet light, X-rays, electron beams or ion beams and can undergo photochemical reactions. When PSPI is used as a photoresist, a photochemical reaction occurs in the exposed area, resulting in a significant difference in the solubility of PSPI in the developer between the exposed area and the non-exposed area, and a photolithographic pattern is formed after development. Compared with traditional photoresists, PSPI photoresists directly form the dielectric insulation layer required for the device after photolithographic patterning, avoiding the cumbersome process of traditional photoresists that need to be repeatedly etched and removed after the pattern is transferred to the substrate material. Therefore, it has the advantages of saving costs, simplifying processes, and improving pattern accuracy. It is widely used in the surface planarization layer and support layer of flexible display thin film transistors (TFTs), pixel definition layers (PDLs), and rewiring layers and interlayer insulation in semiconductor manufacturing. It is one of the new materials urgently needed by the country.

[0003] According to the different photoreaction mechanisms, PSPI can be divided into negative and positive PSPI. The former undergoes cross-linking and curing after exposure to inhibit dissolution, dissolving the unexposed part, and is usually developed with organic solvents, while the latter promotes dissolution after exposure, and the unexposed part remains on the substrate surface after development, and is generally developed with alkaline aqueous solution. The earliest commercialized PSPI photoresist was mainly negative PSPI, which introduced methacrylate photosensitive groups on the macromolecular chain through esterification or ionization reactions to form polyamide esters or polyamide salts, which undergo cross-linking reactions after exposure. Compared with positive PSPI, negative PSPI has advantages such as strong adhesion to the substrate and high sensitivity, but it also has obvious disadvantages. For example, ester-type and salt-type negative PSPI need to undergo thermal imidization reaction (>350°C) after development to obtain a stable patterned film. The volatilization of a large amount of solvents and by-products in this heat treatment process can easily lead to low film retention rate (~50%) and mismatch between the thermal expansion coefficients of the PSPI film and the substrate. At the same time, with the development of technologies such as 5G communications, electronic materials are required to have low dielectric constants and dielectric losses to improve the communication quality of the equipment. In addition, when PSPI photoresist is used, the adhesion between PSPI resin and glass or silicon wafers is also one of the important technical indicators. However, the interface compatibility between polymer materials and inorganic materials such as glass or silicon wafers has always been one of the difficult problems that need to be broken through in this field. For example, the invention patent (CN 202111518790.9) discloses a method for reducing the dielectric constant and dielectric loss of PSPI resin by introducing a low-polarity alicyclic structural unit, and the invention patent (CN 202211061598.6) discloses a method for improving the adhesion between the resin and the silicon wafer or glass surface by adding a silane coupling agent to a photosensitive polyimide composition, but the disclosed technology does not provide a PSPI resin that can simultaneously improve the dielectric properties and the interfacial viscosity of the resin. Therefore, it is necessary to effectively design the structure of the polyimide resin and develop a PSPI resin with high resolution, low dielectric constant, low expansion coefficient and high adhesion. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a photosensitive polyimide resin, a polyimide composition and a preparation method thereof, so as to overcome the defect that the PSPI resin in the prior art cannot have high resolution, low dielectric constant, low expansion coefficient and high adhesion.

[0005] The present invention provides a photosensitive polyimide resin, the molecular structure of which is shown below:

[0006]

[0007] The X structure is derived from amino hyperbranched polysiloxane or its derivatives, the Y structure is derived from a diamine monomer containing a photosensitive unit, and the Ar structure is derived from a dianhydride monomer; and the molar ratio of the repeating units m:n is 0.5:9.5 to 3:7.

[0008] Preferably, the X structure is derived from one of an amino hyperbranched polysiloxane NH2-HBPSi and an amino hyperbranched polysiloxane containing trifluoromethyl group NH2-CF3-HBPSi.

[0009] Preferably, the branching degree of the amino hyperbranched polysiloxane is 0.5-0.9, and the surface amino group content is 0.1-0.4 mmol / g.

[0010] Preferably, the Y structure is one of the following structures:

[0011]

[0012] In the formula, the R group is one of the following structures:

[0013]

[0014] Preferably, the diamine monomer in the Y structure is one of 3,5-diaminobenzoic acid (DABA), 4,4'-diaminobiphenyl-2,2-dicarboxylic acid (2,2'-DCB), and 4,4'-diamino-3,3'-dicarboxy terphenyl (4,4'-DTDA).

[0015] Preferably, the Ar structure is one of the following structures:

[0016]

[0017] Preferably, the dianhydride monomer is one of cyclobutanetetracarboxylic dianhydride (CBDA), 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA), bisphenol A diether dianhydride (BPADA), pyromellitic anhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 4,4'-oxydiphthalic anhydride (ODPA), 3,3',4,4'-dibenzophenone tetracarboxylic dianhydride (BTDA), 3,3,4,4-diphenylsulfone tetracarboxylic dianhydride (DSDA) or hexafluorodianhydride (6FDA).

[0018] The present invention provides a method for preparing a photosensitive polyimide resin, comprising the following steps:

[0019] (1) Under nitrogen protection, dissolving the amino hyperbranched polysiloxane and the diamine monomer in a non-protonic polar solvent, stirring them thoroughly, and mixing them uniformly; then adding the dianhydride monomer in an amount equal to the sum of the amino hyperbranched polysiloxane and the diamine monomer to the reaction system, stirring them thoroughly at 0-5° C. for 20-28 hours to obtain a transparent viscous polyimide precursor solution;

[0020] (2) Under nitrogen protection, add a compound containing a photosensitive unit and a catalyst in an amount equimolar to the diamine monomer to the reaction solution of step (1), and react at 60-80° C. for 4-8 hours to synthesize a photosensitive polyimide resin.

[0021] Preferably, the solid content of the reactants in the reaction system in step (1) is 10 wt%-20 wt%.

[0022] Preferably, the aprotic polar solvent in step (1) is one of N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF) or dimethyl sulfoxide (DMSO).

[0023] Preferably, the compound containing the photosensitive unit in step (2) is one of glycidyl methacrylate, glycidyl acrylate or cinnamyl alcohol.

[0024] Preferably, the catalyst in step (2) is triethylenediamine, and the added amount is 1wt%-3wt%.

[0025] The invention provides a photosensitive polyimide resin composition, comprising the photosensitive polyimide resin, an initiator and an active diluent.

[0026] Preferably, the initiator is one of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (Irgacure 819), 2-hydroxy-2-methyl-1-phenyl-1-propanone (Irgacure 1173), and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO); and the active diluent is one of 1-vinyl-2-pyrrolidone (NVP), butyl acrylate (BA), 1,6-hexanediol diacrylate (HDDA), and tripropylene glycol diacrylate (TPGDA).

[0027] More preferably, the initiator is one of Irgacure 819 and Irgacure 1173.

[0028] More preferably, the reactive diluent is one of NVP and TPGDA.

[0029] Preferably, the content of the initiator in the photosensitive polyimide resin composition is 1wt%-5wt%, and the content of the reactive diluent is 10wt%-20wt%.

[0030] More preferably, the content of the initiator is 3 wt % and the content of the reactive diluent is 10 wt %.

[0031] The present invention also provides a method for preparing a photosensitive polyimide resin composition, comprising the following steps: adding an initiator and an active diluent to a photosensitive polyimide resin under nitrogen protection, and stirring the mixture sufficiently to obtain the photosensitive polyimide resin composition.

[0032] The present invention also provides a polyimide patterned film, which is prepared by the following steps: spin coating a photosensitive polyimide resin composition on a silicon wafer surface, soft baking at low temperature, exposing it under an exposure machine, developing it, and baking it at high temperature to obtain a film.

[0033] Preferably, the polyimide patterned film is prepared by the following steps: spin coating the photosensitive polyimide resin composition on the surface of the silicon wafer, soft baking at 80° C. for 10 min, and then exposing it to light (350 mJ / cm 2 ), and finally developed and high-temperature baked (300°C, 10min) to obtain a patterned film.

[0034] Beneficial Effects

[0035] (1) The present invention introduces an amino hyperbranched polysiloxane unit with hydrophobic properties into the main chain of the polyimide molecule by structurally designing the main chain of the polyimide resin. The micro-crosslinked structure between the molecular chains formed by the above structure and the crosslinking reaction of the photosensitive unit can effectively improve the resolution of the photoresist and reduce the thermal expansion coefficient of the patterned film.

[0036] (2) The present invention is based on the low polarity and hydrophobic properties of the rich Si-O-Si units in the hyperbranched polysiloxane, which can reduce the dielectric constant of the patterned film;

[0037] (3) In addition, the Si-O-Si network unit in the main chain of the polyimide of the present invention has better interface compatibility with glass and silicon wafers, thereby forming a stronger interface force, improving the adhesion between the photoresist and the substrate, thereby developing a high-adhesion photoresist material. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the photolithographic pattern of the photosensitive polyimide photoresist prepared in Example 1. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0040] Performance test conditions of polyimide photoresist and patterned film thereof in the embodiments and comparative examples of the present invention:

[0041] Photoresist exposure and development: using the HS-6200 fully automatic exposure machine of Suzhou HiSilicon Microelectronics Technology Co., Ltd., and the developer using N-methyl-pyrrolidone (NMP);

[0042] Thermal expansion coefficient test: Use the thermal mechanical analyzer (Q400) of TA Company of the United States for testing;

[0043] Dielectric performance test: The test was conducted using the Novocontrol concept 40 broadband dielectric impedance spectrometer from the German Novocontrol company;

[0044] Adhesion test: The photosensitive polyimide photoresist is scraped onto a smooth silicon wafer, and a patterned film is formed on the surface of the silicon wafer through processes such as exposure, development, drying, and post-baking. The test is conducted using the KJ-1065A peeling force tester produced by Kejian Instruments.

[0045] Example 1

[0046] Under nitrogen protection, the amino hyperbranched polysiloxane NH2-HBPSi and the diamine monomer DABA are dispersed in a three-necked flask containing N,N-dimethylacetamide (DMAc) solvent, wherein the molar ratio of NH2-HBPSi:DABA is 3:7. After being fully dissolved, the dianhydride monomer BTDA is added to the reaction system in an amount equal to the sum of NH2-HBPSi and DABA, the solid content of the reactants is controlled to be 15wt%, the reaction temperature is controlled to 5°C, and stirred for 24h to obtain a transparent viscous polyamic acid precursor solution. Under nitrogen protection, glycidyl methacrylate and catalyst triethylenediamine (1wt%) in an amount equal to DABA are added to the above reaction solution, the reaction temperature is controlled to 80°C, and the reaction is reacted for 5h to obtain a photosensitive polyimide resin.

[0047] 3 wt % of initiator Irgacure 819 and 10 wt % of active diluent NVP were added to the photosensitive polyimide resin and stirred thoroughly to obtain a photosensitive polyimide resin composition.

[0048] The polyimide photoresist was spin-coated on the clean silicon wafer surface and soft-baked at 80°C for 10 min. Then, it was exposed under an exposure machine (350 mJ / cm 2 ), and finally developed and baked at high temperature (300°C, 10 min) to obtain a patterned film, such as Figure 1 The photolithographic pattern of the photosensitive polyimide photoresist is shown.

[0049] Example 2

[0050] Under nitrogen protection, the amino hyperbranched polysiloxane NH2-HBPSi and the diamine monomer DABA are dispersed in a three-necked flask containing N,N-dimethylacetamide (DMAc) solvent, wherein the molar ratio of NH2-HBPSi:DABA is 1:9. After being fully dissolved, the dianhydride monomer BTDA is added to the reaction system in an amount equal to the sum of NH2-HBPSi and DABA, the solid content of the reactants is controlled to be 15wt%, the reaction temperature is controlled to 5°C, and stirred for 24h to obtain a transparent viscous polyamic acid precursor solution. Under nitrogen protection, methyl glycidyl methacrylate and catalyst triethylenediamine (1wt%) are added to the above reaction solution in an amount equal to the molar amount of DABA, the reaction temperature is controlled to 80°C, and the reaction is reacted for 5h to obtain a photosensitive polyimide resin.

[0051] 3 wt % of initiator Irgacure 819 and 10 wt % of active diluent NVP were added to the photosensitive polyimide resin and stirred thoroughly to obtain a photosensitive polyimide resin composition.

[0052] The polyimide photoresist was spin-coated on the clean silicon wafer surface and soft-baked at 80°C for 10 min. Then, it was exposed under an exposure machine (350 mJ / cm 2 ), and finally developed and high-temperature baked (300°C, 10min) to obtain a patterned film.

[0053] Example 3

[0054] Under nitrogen protection, the amino hyperbranched polysiloxane NH2-HBPSi and the diamine monomer 2,2'-DCB are dispersed in a three-necked flask containing N,N-dimethylacetamide (DMAc) solvent, wherein the molar ratio of NH2-HBPSi:2,2'-DCB is 3:7. After being fully dissolved, the dianhydride monomer BPDA is added to the reaction system in an amount equal to the sum of NH2-HBPSi and 2,2'-DCB, the solid content of the reactants is controlled to be 15wt%, the reaction temperature is controlled to be 5°C, and the reaction is stirred for 24h to obtain a transparent viscous polyamic acid precursor solution. Under nitrogen protection, methyl glycidyl methacrylate and catalyst triethylenediamine (1wt%) are added to the above reaction solution in an amount equal to the molar amount of 2,2'-DCB, the reaction temperature is controlled to be 80°C, and the reaction is reacted for 5h to obtain a photosensitive polyimide resin.

[0055] 3 wt % of initiator Irgacure 819 and 10 wt % of active diluent NVP were added to the photosensitive polyimide resin and stirred thoroughly to obtain a photosensitive polyimide resin composition.

[0056] The polyimide photoresist was spin-coated on the clean silicon wafer surface and soft-baked at 80°C for 10 min. Then, it was exposed under an exposure machine (350 mJ / cm 2 ), and finally developed and high-temperature baked (300°C, 10min) to obtain a patterned film.

[0057] Example 4

[0058] Under nitrogen protection, the trifluoromethyl-containing amino hyperbranched polysiloxane NH2-CF3-HBPSi and the diamine monomer DABA are dispersed in a three-necked flask containing N,N-dimethylacetamide (DMAc) solvent, wherein the molar ratio of NH2-CF3-HBPSi:DABA is 3:7. After being fully dissolved, the dianhydride monomer BTDA is added to the reaction system in an amount equal to the sum of NH2-CF3-HBPSi and DABA, the solid content of the reactants is controlled to be 15wt%, the reaction temperature is controlled to be 5°C, and the reaction is stirred for 24h to obtain a transparent viscous polyamic acid precursor solution. Under nitrogen protection, methyl glycidyl methacrylate and catalyst triethylenediamine (1wt%) are added to the above reaction solution in an amount equal to the molar amount of DABA, the reaction temperature is controlled to be 80°C, and the reaction is reacted for 5h to obtain a photosensitive polyimide resin.

[0059] 3 wt % of initiator Irgacure 819 and 10 wt % of active diluent NVP were added to the photosensitive polyimide resin and stirred thoroughly to obtain a photosensitive polyimide resin composition.

[0060] The polyimide photoresist was spin-coated on the clean silicon wafer surface and soft-baked at 80°C for 10 min. Then, it was exposed under an exposure machine (350 mJ / cm 2 ), and finally developed and high-temperature baked (300°C, 10min) to obtain a patterned film.

[0061] Example 5

[0062] Under nitrogen protection, the trifluoromethyl-containing amino hyperbranched polysiloxane NH2-CF3-HBPSi and the diamine monomer DABA are dispersed in a three-necked flask containing N,N-dimethylacetamide (DMAc) solvent, wherein the molar ratio of NH2-CF3-HBPSi:DABA is 3:7. After being fully dissolved, the dianhydride monomer BTDA is added to the reaction system in an amount equal to the sum of NH2-CF3-HBPSi and DABA, the solid content of the reactants is controlled to be 15wt%, the reaction temperature is controlled to be 5°C, and the reaction is stirred for 24h to obtain a transparent viscous polyamic acid precursor solution. Under nitrogen protection, methyl glycidyl methacrylate and catalyst triethylenediamine (1wt%) are added to the above reaction solution in an amount equal to the molar amount of DABA, the reaction temperature is controlled to be 80°C, and the reaction is reacted for 5h to obtain a photosensitive polyimide resin.

[0063] 3 wt % of initiator Irgacure 1173 and 10 wt % of active diluent TPGDA were added to the photosensitive polyimide resin and stirred thoroughly to obtain a photosensitive polyimide resin composition.

[0064] The polyimide photoresist was spin-coated on the clean silicon wafer surface and soft-baked at 80°C for 10 min. Then, it was exposed under an exposure machine (350 mJ / cm 2 ), and finally developed and high-temperature baked (300°C, 10min) to obtain a patterned film.

[0065] Comparative Example 1

[0066] Under nitrogen protection, the diamine monomer DABA is dispersed in a three-necked flask containing N,N-dimethylacetamide (DMAc) solvent. After being fully dissolved, the dianhydride monomer BTDA is added to the reaction system in an equal molar amount to DABA, the solid content of the reactants is controlled to 15wt%, the reaction temperature is controlled to 5°C, and stirred for 24h to obtain a viscous polyamic acid precursor solution. Under nitrogen protection, glycidyl methacrylate and catalyst triethylenediamine (1wt%) are added to the above reaction solution in an equal molar amount to DABA, the reaction temperature is controlled to 80°C, and the reaction is carried out for 5h to obtain a photosensitive polyimide resin.

[0067] 3 wt % of initiator Irgacure 819 and 10 wt % of active diluent NVP were added to the photosensitive polyimide resin and stirred thoroughly to obtain a photosensitive polyimide resin composition.

[0068] The polyimide photoresist was spin-coated on the clean silicon wafer surface and soft-baked at 80°C for 10 min. Then, it was exposed under an exposure machine (350 mJ / cm 2 ), and finally developed and high-temperature baked (300°C, 10min) to obtain a patterned film.

[0069] Comparative Example 2

[0070] Under nitrogen protection, the hyperbranched polysiloxane HBPSi without amino units and the diamine monomer DABA are dispersed in a three-necked flask containing N, N-dimethylacetamide (DMAc) solvent, wherein the molar ratio of HBPSi:DABA is 3:7. After being fully dissolved, the dianhydride monomer BTDA in an amount equal to the sum of HBPSi and DABA is added to the reaction system, the solid content of the reactants is controlled to be 15wt%, the reaction temperature is controlled to 5°C, and stirred for 24h to obtain a viscous polyamic acid precursor solution. Under nitrogen protection, glycidyl methacrylate and catalyst triethylenediamine (1wt%) in an amount equal to DABA are added to the above reaction solution, the reaction temperature is controlled to 80°C, and the reaction is reacted for 5h to obtain a photosensitive polyimide resin.

[0071] 3 wt % of initiator Irgacure 819 and 10 wt % of active diluent NVP were added to the photosensitive polyimide resin and stirred thoroughly to obtain a photosensitive polyimide resin composition.

[0072] The polyimide photoresist was spin-coated on the clean silicon wafer surface and soft-baked at 80°C for 10 min. Then, it was exposed under an exposure machine (350 mJ / cm 2 ), and finally developed and high-temperature baked (300°C, 10min) to obtain a patterned film.

[0073] Table 1 is a comparison of the properties of the photosensitive polyimide photoresists obtained in the examples of the present invention and the comparative examples.

[0074] Table 1

[0075]

[0076] It can be seen from Table 1 that the photosensitive polyimide photoresist prepared by the present invention has excellent properties of high resolution, low dielectric constant, low expansion coefficient and high adhesion compared with the polyimide photoresist without amino hyperbranched polysiloxane.

Claims

1. A photosensitive polyimide resin, characterized in that: The molecular structure is shown below: The X structure is derived from amino hyperbranched polysiloxane or its derivatives, the Y structure is derived from a diamine monomer containing a photosensitive unit, and the Ar structure is derived from a dianhydride monomer; and the molar ratio of the repeating units m:n is 0.5:9.5 to 3:

7.

2. The photosensitive polyimide resin according to claim 1, characterized in that: The X structure is derived from one of the amino hyperbranched polysiloxane NH2-HBPSi and the amino hyperbranched polysiloxane NH2-CF3-HBPSi containing trifluoromethyl.

3. The photosensitive polyimide resin according to claim 1, characterized in that: The Y structure is one of the following structures: In the formula, the R group is one of the following structures:

4. The photosensitive polyimide resin according to claim 1, characterized in that: The Ar structure is one of the following structures:

5. The method for preparing the photosensitive polyimide resin according to any one of claims 1 to 4, comprising the following steps: (1) Under nitrogen protection, dissolving the amino hyperbranched polysiloxane and the diamine monomer in a non-protonic polar solvent, stirring them thoroughly, and mixing them uniformly; then adding the dianhydride monomer in an amount equal to the sum of the amino hyperbranched polysiloxane and the diamine monomer to the reaction system, stirring them thoroughly at 0-5° C. for 20-28 hours to obtain a transparent viscous polyimide precursor solution; (2) Under nitrogen protection, add a compound containing a photosensitive unit and a catalyst in an amount equimolar to the diamine monomer to the polyimide precursor solution of step (1), and react at 60-80° C. for 4-8 hours to obtain a photosensitive polyimide resin.

6. A photosensitive polyimide resin composition, comprising the photosensitive polyimide resin according to claim 1, an initiator and a reactive diluent.

7. The photosensitive polyimide resin composition according to claim 6, characterized in that: The initiator is one of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide; the active diluent is one of 1-vinyl-2-pyrrolidone, butyl acrylate, 1,6-hexanediol diacrylate, and tripropylene glycol diacrylate.

8. The photosensitive polyimide resin composition according to claim 6, characterized in that: The content of the initiator is 1wt%-5wt%, and the content of the active diluent is 10wt%-20wt%.

9. The method for preparing the photosensitive polyimide resin composition according to any one of claims 6 to 8, characterized in that: The method comprises the following steps: adding an initiator and an active diluent to a photosensitive polyimide resin under nitrogen protection, and fully stirring the mixture to obtain a photosensitive polyimide resin composition.

10. A polyimide patterned film, prepared by the following steps: spin coating the photosensitive polyimide resin composition of claim 6 on a silicon wafer surface, soft baking at low temperature, exposing it under an exposure machine, developing it, and baking it at high temperature to obtain a film.

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