Polyamic acid salt, negative photosensitive polyimide, preparation method of negative photosensitive polyimide and electronic product

Abstract

The invention provides polyamic acid salt, negative photosensitive polyimide, a preparation method of the negative photosensitive polyimide and an electronic product, and relates to the technical field of microelectronics. The structural general formula of the polyamide acid salt is # imgabs0 #, and the preparation method of the polyamide acid salt comprises the following steps: performing a first reaction on a diamine monomer and a dianhydride monomer in a protective atmosphere to obtain a polyamide acid solution, then adding a photosensitive vinylpyridine compound, and performing a second reaction in a dark place to obtain the polyamide acid salt. The polyamic acid salt provided by the invention is a core raw material for obtaining the negative photosensitive polyimide which is low in dielectric constant and can be developed in an alkaline solution, and the obtained negative photosensitive polyimide has good thermal stability and mechanical properties and relatively low dielectric constant and can be developed in an alkaline solution.

Description

Technical Field

[0001] The present application relates to the field of microelectronic technology, and in particular to a polyamic acid salt, a negative photosensitive polyimide, a preparation method thereof, and an electronic product. Background Art

[0002] With the rapid development of miniaturization of electronic products, the selection of materials is becoming more and more important in the microelectronics industry. In order to achieve high-efficiency production and reliability of insulation layers in microelectronics manufacturing, polymer materials used to manufacture flexible substrates must have excellent mechanical properties, good thermal stability and low dielectric properties.

[0003] Photosensitive polyimide (PSPI) has promoted the development of large-scale integrated circuit semiconductors (LSI) and is widely used as a buffer coating, insulating coating and insulating layer in microelectronic devices. Photosensitive polyimide has the excellent performance of polyimide and can be used as a photolithography material, which solves the complexity of the previous photolithography process and accelerates the rapid development of photosensitive polyimide. Negative polyimide is the earliest commercial product, but most of them use organic solvents for development, which is not good for the environment. Documents CN114957662 A and CN114907567A both use alkaline solution development, which greatly reduces environmental pollution.

[0004] Therefore, negative photosensitive polyimide that can be developed using alkaline is the future development method, and negative photosensitive polyimide and its raw materials have become research hotspots. Summary of the invention

[0005] The purpose of the present application is to provide a polyamic acid salt, a negative photosensitive polyimide, a preparation method thereof and an electronic product to solve the above problems.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] A polyamic acid salt, the general structural formula of which is:

[0008]

[0009] Wherein, Ar1 is selected from one or more of the following structures:

[0010]

[0011] Ar2 is selected from one or more of the following structures:

[0012]

[0013] Ar3 is selected from one or more of the following structures:

[0014]

[0015] Ar4 is selected from one or more of the following structures:

[0016]

[0017] R3N is selected from any one or more of the following structures:

[0018]

[0019] m and n are each independent positive integers.

[0020] By preferably selecting m and n, the weight average molecular weight of the polyamic acid salt is controlled to be 10,000 to 200,000.

[0021] The present application also provides a method for preparing the polyamic acid salt, comprising:

[0022] The diamine monomer and the dianhydride monomer are subjected to a first reaction under a protective atmosphere to obtain a polyamic acid solution, and then a photosensitive vinyl pyridine compound is added thereto, and a second reaction is carried out in the dark to obtain the polyamic acid salt.

[0023] Preferably, the preparation method of polyamic acid salt meets one or more of the following conditions:

[0024] (1) The molar ratio of the diamine monomer to the dianhydride monomer is 1:(1.05-1.10);

[0025] (2) The diamine monomers include hydroxyl-containing diamine monomers and fat-containing diamine monomers, and the dianhydride monomers include fat-containing dianhydride monomers and fluorine-containing dianhydride monomers;

[0026] (3) the molar ratio of the dianhydride monomer to the photosensitive vinyl pyridine compound is 1:(2.0-2.1);

[0027] (4) The temperature of the first reaction is -5°C to 25°C, and the time is 8 to 24 hours;

[0028] (5) The temperature of the second reaction is room temperature and the time is 2 to 6 hours;

[0029] (6) The photosensitive vinyl pyridine compound includes one or more of 4-vinyl pyridine, 3-vinyl pyridine, and methyl vinyl pyridine;

[0030] (7) The system of the first reaction further includes an organic solvent, and the organic solvent includes one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.

[0031] Preferably, the preparation method of the polyamic acid salt satisfies one or more of the following conditions:

[0032] (1) In the diamine monomer, the molar content of the hydroxyl-containing diamine monomer is 10% to 25%;

[0033] (2) In the dianhydride monomer, the molar content of the fluorine-containing dianhydride monomer is 10% to 25%;

[0034] (3) The hydroxyl diamine monomer includes one or more of 3,3'-diamino-4,4'-dihydroxybiphenyl, 3,3'-dihydroxybenzidine, and 3-hydroxybenzidine; the fatty diamine monomer includes one or more of 1,4-cyclohexanediamine, 4,4'-diaminodicyclohexylmethane, and 2,2'-dimethyl-4,4'-diaminobiphenyl; the fatty dianhydride monomer includes one or more of 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, and 1,3-dimethyl-cyclobutanetetracarboxylic acid dianhydride; the fluorine-containing dianhydride monomer includes one or more of 4,4'-(hexafluoroisopropyl)diphthalic anhydride and 3,4-dicarboxy-1,2,3,4-tetrahydro-6-trifluoromethyl-1-naphthalenesuccinic acid dianhydride.

[0035] The present application also provides a negative photosensitive polyimide, the raw materials of which include the polyamic acid salt.

[0036] The present application also provides a method for preparing the negative photosensitive polyimide, comprising:

[0037] The polyamic acid salt and the photoinitiator are mixed to obtain a photosensitive polyamic acid solution;

[0038] placing the photosensitive polyamic acid solution on a substrate and drying it to obtain a polymer film;

[0039] The polymer film is sequentially subjected to ultraviolet exposure and alkaline development to obtain a negative film having a target pattern;

[0040] The negative film is heated and imidized to obtain the negative photosensitive polyimide.

[0041] Preferably, the photoinitiator includes one or more of bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, Michler's ketone, benzophenone, 2,4-dihydroxybenzophenone, benzoin, benzoin dimethyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, α,α-diethoxyacetophenone, α-hydroxyalkyl phenone, and α-aminoalkylbenzene;

[0042] and / or,

[0043] The amount of the photoinitiator used is 0.2-10 wt % of the polyamic acid salt.

[0044] Preferably, the mixing time is 2 to 6 hours;

[0045] and / or,

[0046] The heating imidization is carried out by programmed temperature increase, specifically including: heating from room temperature to 60-100° C. and keeping the temperature for no more than 4 hours, then heating to 100-140° C. and keeping the temperature for no more than 4 hours, then heating to 150-250° C. and keeping the temperature for no more than 4 hours, and finally heating to 250-350° C. and keeping the temperature for no more than 4 hours.

[0047] Preferably, the polymer film has a thickness of 5 to 150 μm.

[0048] The present application also provides an electronic product, comprising the negative photosensitive polyimide.

[0049] Compared with the prior art, the beneficial effects of this application include:

[0050] The present application designs an Ar group and uses a vinyl pyridine group as a photosensitive group, and grafts it onto a polyamic acid chain to generate a polyamic acid salt. The molecular polarizability of the fluorine atoms and the fatty groups in the Ar group is low, which can reduce the dielectric constant of the polymer. Hydroxyl diamine is used as a synthetic monomer to achieve alkaline development. Therefore, alkaline-developable, low-dielectric negative photosensitive polyimide is of great significance in the development of semiconductors. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0052] Figure 1 This is a photolithography effect diagram of different line widths obtained in Example 1. DETAILED DESCRIPTION

[0053] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0054] Example 1

[0055] This embodiment provides a polyamic acid salt, and the preparation method thereof is as follows:

[0056] Under N2 atmosphere, 15mmol 3,3'-dihydroxybenzidine and 15mmol 1,4-cyclohexanediamine were added into a three-necked flask, and 100ml N-methylpyrrolidone was added thereto. After the diamine was completely dissolved, 15mmol hexafluorodianhydride and 15mmol cyclobutanetetracarboxylic dianhydride were slowly added, and then 60mmol photosensitive 4-vinylpyridine was added. The mixture was reacted for 2h in the dark to obtain a polyamic acid salt solution.

[0057] This embodiment provides a negative photosensitive polyimide, and the preparation method thereof is as follows:

[0058] 5 wt % of photoinitiator Michler's ketone was added to the polyamic acid salt solution, and the mixture was stirred for 2 h to obtain a photosensitive polyamic acid solution.

[0059] Take 5g of photosensitive polyamic acid solution and evenly coat it on a clean and smooth silicon wafer or glass plate, remove most of the solvent in a vacuum oven at 80°C to obtain a polymer film with a non-sticky surface; expose the film to an LED ultraviolet lamp with a central emission wavelength of 365nm for a certain period of time, then develop it with a tetramethylammonium hydroxide (TMAH) aqueous solution at room temperature, and then wash it with deionized water to obtain a negative pattern.

[0060] The pattern was placed in a temperature rising program of 80°C / 2h, 120°C / 2h, 200°C / 2h, and 300°C / 2h to finally obtain a negative photosensitive polyimide pattern.

[0061] Figure 1 This is a photolithography effect diagram of different line widths obtained in Example 1.

[0062] Example 2

[0063] This embodiment provides a polyamic acid salt, and the preparation method thereof is as follows:

[0064] Under N2 atmosphere, 15mmol 3,3'-dihydroxybenzidine and 15mmol 4,4'-diaminodicyclohexylmethane were added into a three-necked flask, and 100ml N,N-dimethylformamide was added thereto. After the diamine was completely dissolved, 15mmol hexafluorodianhydride and 15mmol 1,2,4,5-cyclohexanetetracarboxylic dianhydride were slowly added, and then 60mmol photosensitive 4-vinylpyridine was added. The mixture was reacted for 2h in the dark to obtain a polyamic acid salt solution.

[0065] This embodiment provides a negative photosensitive polyimide, and the preparation method thereof is as follows:

[0066] 5 wt % of photoinitiator Michler's ketone was added to the polyamic acid salt solution, and the mixture was stirred for 2 h to obtain a photosensitive polyamic acid solution.

[0067] Take 5g of photosensitive polyamic acid solution and evenly coat it on a clean and smooth silicon wafer or glass plate, remove most of the solvent in a vacuum oven at 80°C to obtain a polymer film with a non-sticky surface; expose the film to an LED ultraviolet lamp with a central emission wavelength of 365nm for a certain period of time, then develop it with a tetramethylammonium hydroxide (TMAH) aqueous solution at room temperature, and then wash it with deionized water to obtain a negative pattern.

[0068] The pattern was placed in a temperature rising program of 80°C / 2h, 120°C / 2h, 200°C / 2h, and 300°C / 2h to finally obtain a negative photosensitive polyimide pattern.

[0069] Example 3

[0070] This embodiment provides a polyamic acid salt, and the preparation method thereof is as follows:

[0071] Under N2 atmosphere, 15mmol 3-hydroxybenzidine and 15mmol 4,4'-diaminodicyclohexylmethane were added into a three-necked flask, and 100ml N,N-dimethylacetamide was added thereto. After the diamine was completely dissolved, 15mmol hexafluorodianhydride and 15mmol 1,2,4,5-cyclohexanetetracarboxylic dianhydride were slowly added, and then 60mmol photosensitive 4-vinylpyridine was added. The mixture was reacted for 2h in the dark to obtain a polyamic acid salt solution.

[0072] This embodiment provides a negative photosensitive polyimide, and the preparation method thereof is as follows:

[0073] 5 wt % of photoinitiator Michler's ketone was added to the polyamic acid salt solution, and the mixture was stirred for 2 h to obtain a photosensitive polyamic acid solution.

[0074] Take 5g of photosensitive polyamic acid solution and evenly coat it on a clean and smooth silicon wafer or glass plate, remove most of the solvent in a vacuum oven at 80°C to obtain a polymer film with a non-sticky surface; expose the film to an LED ultraviolet lamp with a central emission wavelength of 365nm for a certain period of time, then develop it with a tetramethylammonium hydroxide (TMAH) aqueous solution at room temperature, and then wash it with deionized water to obtain a negative pattern.

[0075] The pattern was placed in a temperature rising program of 80°C / 2h, 120°C / 2h, 200°C / 2h, and 300°C / 2h to finally obtain a negative photosensitive polyimide pattern.

[0076] Comparative Example 1

[0077] This comparative example provides a polyamic acid salt, and its preparation method is as follows:

[0078] Under N2 atmosphere, 5mmol 3,3'-dihydroxybenzidine and 15mmol 1,4-cyclohexanediamine were added into a three-necked flask, and 100ml N-methylpyrrolidone was added thereto. After the diamine was completely dissolved, 15mmol hexafluorodianhydride and 5mmol cyclobutanetetracarboxylic dianhydride were slowly added, and then 40mmol photosensitive 4-vinylpyridine was added. The mixture was reacted for 2h in the dark to obtain a polyamic acid salt solution.

[0079] This comparative example provides a negative photosensitive polyimide, and the preparation method thereof is as follows:

[0080] 5 wt % of photoinitiator Michler's ketone was added to the polyamic acid salt solution, and the mixture was stirred for 2 h to obtain a photosensitive polyamic acid solution.

[0081] Take 5g of photosensitive polyamic acid solution and evenly coat it on a clean and smooth silicon wafer or glass plate, remove most of the solvent in a vacuum oven at 80°C to obtain a polymer film with a non-sticky surface; expose the film to an LED ultraviolet lamp with a central emission wavelength of 365nm for a certain period of time, then develop it with a tetramethylammonium hydroxide (TMAH) aqueous solution at room temperature, and then wash it with deionized water to obtain a negative pattern.

[0082] The pattern was placed in a temperature rising program of 80°C / 2h, 120°C / 2h, 200°C / 2h, and 300°C / 2h to finally obtain a negative photosensitive polyimide pattern.

[0083] Comparative Example 2

[0084] This comparative example provides a polyamic acid salt, and its preparation method is as follows:

[0085] Under N2 atmosphere, 15mmol 3,3'-dihydroxybenzidine and 5mmol 4,4'-diaminodicyclohexylmethane were added into a three-necked flask, and 100ml N,N-dimethylformamide was added thereto. After the diamine was completely dissolved, 15mmol hexafluorodianhydride and 5mmol 1,2,4,5-cyclohexanetetracarboxylic dianhydride were slowly added, and then 40mmol photosensitive 4-vinylpyridine was added. The mixture was reacted for 2h in the dark to obtain a polyamic acid salt solution.

[0086] This comparative example provides a negative photosensitive polyimide, and the preparation method thereof is as follows:

[0087] 5 wt % of photoinitiator Michler's ketone was added to the polyamic acid salt solution, and the mixture was stirred for 2 h to obtain a photosensitive polyamic acid solution.

[0088] Take 5g of photosensitive polyamic acid solution and evenly coat it on a clean and smooth silicon wafer or glass plate, remove most of the solvent in a vacuum oven at 80°C to obtain a polymer film with a non-sticky surface; expose the film to an LED ultraviolet lamp with a central emission wavelength of 365nm for a certain period of time, then develop it with a tetramethylammonium hydroxide (TMAH) aqueous solution at room temperature, and then wash it with deionized water to obtain a negative pattern.

[0089] The pattern was placed in a temperature rising program of 80°C / 2h, 120°C / 2h, 200°C / 2h, and 300°C / 2h to finally obtain a negative photosensitive polyimide pattern.

[0090] Comparative Example 3

[0091] This comparative example provides a polyamic acid salt, and its preparation method is as follows:

[0092] Under N2 atmosphere, 15mmol 3-hydroxybenzidine and 15mmol 4,4'-diaminodicyclohexylmethane were added into a three-necked flask, and 100ml N,N-dimethylacetamide was added thereto. After the diamine was completely dissolved, 15mmol hexafluorodianhydride and 15mmol 1,2,4,5-cyclohexanetetracarboxylic dianhydride were slowly added, and then 60mmol photosensitive dimethylaminoethyl methacrylate was added. The mixture was reacted for 2h in the dark to obtain a polyamic acid salt solution.

[0093] This comparative example provides a negative photosensitive polyimide, and the preparation method thereof is as follows:

[0094] 5 wt % of photoinitiator Michler's ketone was added to the polyamic acid salt solution, and the mixture was stirred for 2 h to obtain a photosensitive polyamic acid solution.

[0095] Take 5g of photosensitive polyamic acid solution and evenly coat it on a clean and smooth silicon wafer or glass plate, remove most of the solvent in a vacuum oven at 80°C to obtain a polymer film with a non-sticky surface; expose the film to an LED ultraviolet lamp with a central emission wavelength of 365nm for a certain period of time, then develop it with a tetramethylammonium hydroxide (TMAH) aqueous solution at room temperature, and then wash it with deionized water to obtain a negative pattern.

[0096] The pattern was placed in a temperature rising program of 80°C / 2h, 120°C / 2h, 200°C / 2h, and 300°C / 2h to finally obtain a negative photosensitive polyimide pattern.

[0097] The photosensitivity, negative pattern resolution and imidization temperature of the polymers obtained in the above examples and comparative examples are shown in Table 1 below.

[0098] Table 1 Performance test data

[0099] PSPI <![CDATA[Photosensitivity (mJ / cm 2 )]]> Resolution(μm) Dielectric constant Example 1 460 20 2.83 Example 2 460 20 2.68 Example 3 455 20 2.72 Comparative Example 1 420 32 3.23 Comparative Example 2 420 31 3.10 Comparative Example 3 410 30 3.16

[0100] From the above data, it can be seen that the negative photosensitive polyimide provided by the present invention has better performance, increases the content of hydroxyl groups, is conducive to alkaline development, and the photosensitivity can reach 460mJ / cm 2 , the resolution can reach 20μm, and increasing the content of fat and fluorine-containing groups can reduce the dielectric constant of PI, with a minimum of 2.68.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A polyamic acid salt, characterized in that: Its general structural formula is: Wherein, Ar1 is selected from one or more of the following structures: Ar2 is selected from one or more of the following structures: Ar3 is selected from one or more of the following structures: Ar4 is selected from one or more of the following structures: R3N is selected from any one or more of the following structures: m and n are each independent positive integers.

2. A method for preparing the polyamic acid salt according to claim 1, characterized in that: include: The diamine monomer and the dianhydride monomer are subjected to a first reaction under a protective atmosphere to obtain a polyamic acid solution, and then a photosensitive vinyl pyridine compound is added thereto, and a second reaction is carried out in the dark to obtain the polyamic acid salt.

3. The method for preparing a polyamic acid salt according to claim 2, characterized in that: One or more of the following conditions are met: (1) The molar ratio of the diamine monomer to the dianhydride monomer is 1:(1.05-1.10); (2) The diamine monomers include hydroxyl-containing diamine monomers and fat-containing diamine monomers, and the dianhydride monomers include fat-containing dianhydride monomers and fluorine-containing dianhydride monomers; (3) the molar ratio of the dianhydride monomer to the photosensitive vinyl pyridine compound is 1:(2.0-2.1); (4) The temperature of the first reaction is -5°C to 25°C, and the time is 8 to 24 hours; (5) The temperature of the second reaction is room temperature and the time is 2 to 6 hours; (6) The photosensitive vinyl pyridine compound includes one or more of 4-vinyl pyridine, 3-vinyl pyridine, and methyl vinyl pyridine; (7) The system of the first reaction further includes an organic solvent, and the organic solvent includes one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.

4. The method for preparing a polyamic acid salt according to claim 3, characterized in that: One or more of the following conditions are met: (1) In the diamine monomer, the molar content of the hydroxyl-containing diamine monomer is 10% to 25%; (2) In the dianhydride monomer, the molar content of the fluorine-containing dianhydride monomer is 10% to 25%; (3) The hydroxyl diamine monomer includes one or more of 3,3'-diamino-4,4'-dihydroxybiphenyl, 3,3'-dihydroxybenzidine, and 3-hydroxybenzidine; the fatty diamine monomer includes one or more of 1,4-cyclohexanediamine, 4,4'-diaminodicyclohexylmethane, and 2,2'-dimethyl-4,4'-diaminobiphenyl; the fatty dianhydride monomer includes one or more of 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, and 1,3-dimethyl-cyclobutanetetracarboxylic acid dianhydride; the fluorine-containing dianhydride monomer includes one or more of 4,4'-(hexafluoroisopropyl)diphthalic anhydride and 3,4-dicarboxy-1,2,3,4-tetrahydro-6-trifluoromethyl-1-naphthalenesuccinic acid dianhydride.

5. A negative photosensitive polyimide, characterized in that: The raw materials include the polyamic acid salt described in claim 1.

6. A method for preparing the negative photosensitive polyimide according to claim 5, characterized in that: include: The polyamic acid salt and the photoinitiator are mixed to obtain a photosensitive polyamic acid solution; placing the photosensitive polyamic acid solution on a substrate and drying it to obtain a polymer film; The polymer film is sequentially subjected to ultraviolet exposure and alkaline development to obtain a negative film having a target pattern; The negative film is heated and imidized to obtain the negative photosensitive polyimide.

7. The method for preparing a negative photosensitive polyimide according to claim 6, characterized in that: The photoinitiator includes one or more of bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, Michler's ketone, benzophenone, 2,4-dihydroxybenzophenone, benzoin, benzoin dimethyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, α,α-diethoxyacetophenone, α-hydroxyalkyl phenone, and α-aminoalkylbenzene; and / or, The amount of the photoinitiator used is 0.2-10 wt % of the polyamic acid salt.

8. The method for preparing a negative photosensitive polyimide according to claim 6, characterized in that: The mixing time is 2 to 6 hours; and / or, The heating imidization is carried out by programmed temperature increase, specifically including: heating from room temperature to 60-100° C. and keeping the temperature for no more than 4 hours, then heating to 100-140° C. and keeping the temperature for no more than 4 hours, then heating to 150-250° C. and keeping the temperature for no more than 4 hours, and finally heating to 250-350° C. and keeping the temperature for no more than 4 hours.

9. The method for preparing a negative photosensitive polyimide according to any one of claims 6 to 8, characterized in that: The polymer film has a thickness of 5-150 μm.

10. An electronic product, characterized in that: The negative photosensitive polyimide according to claim 5 is included.

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