A polyamide acid salt, a negative photosensitive polyimide, a preparation method thereof, and an electronic product

Abstract

The application provides a kind of polyamide acid salt, negative photosensitive polyimide and its preparation method and electronic product, it is related to microelectronic technology field.The structure general formula of polyamide acid salt is: the preparation method of polyamide acid salt includes: under the protection atmosphere, diamine monomer and dianhydride monomer are carried out first reaction to obtain polyamide acid solution, then join photosensitive vinylpyridine compound, and carry out second reaction to obtain the polyamide acid salt.The polyamide acid salt provided in the application is the core raw material for obtaining low dielectric, alkali developable negative photosensitive polyimide, and the obtained negative photosensitive polyimide has good thermal stability, mechanical property, lower dielectric constant and can be developed in alkaline solution.

Description

TECHNICAL FIELD

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

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

[0003] Photosensitive polyimide (PSPI) promotes 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 not only has excellent performance of polyimide, but also can be used as a photoresist material, solving the complexity of the previous photoresist process and accelerating the rapid development of photosensitive polyimide. Negative polyimide is the earliest commercialized product, but most of them are developed with organic solvents, which is harmful to the environment. Documents CN114957662 A and CN114907567 A are developed with alkaline solution, which greatly reduces environmental pollution.

[0004] Therefore, negative photosensitive polyimide capable of being developed with alkaline solution is the development mode in the future, and negative photosensitive polyimide and its raw materials have become a research hotspot. SUMMARY

[0005] The present application aims 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 purpose, the present application adopts the following technical solutions:

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

[0008]

[0009] 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, n are each independently positive integers.

[0020] m, n are preferably controlled so that the weight average molecular weight of the polyamic acid salt is 10,000 to 200,000.

[0021] The 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 vinylpyridine compound is added and subjected to a second reaction in the dark to obtain the polyamic acid salt.

[0023] Preferably, the method for preparing the polyamic acid salt satisfies 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 monomer comprises a hydroxyl-containing diamine monomer and a fatty-containing diamine monomer, and the dianhydride monomer comprises a fatty-containing dianhydride monomer and a fluorine-containing dianhydride monomer;

[0026] (3) the molar ratio of the dianhydride monomer to the photosensitive vinylpyridine 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 8-24h;

[0028] (5) the temperature of the second reaction is room temperature, and the time is 2-6h;

[0029] (6) the photosensitive vinylpyridine compound comprises one or more of 4-vinylpyridine, 3-vinylpyridine, and methylvinylpyridine;

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

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

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

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

[0034] (3) the hydroxyl-containing diamine monomer includes one or more of 3,3'-diamino-4,4'-dihydroxydiphenyl, 3,3'-dihydroxybenzidine, and 3-hydroxybenzidine, the aliphatic diamine monomer includes one or more of 1,4-cyclohexanediamine, 4,4'-diaminodicyclohexylmethane, and 2,2'-dimethyl-4,4'-diaminodiphenyl, the aliphatic dianhydride monomer includes one or more of 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 1,3-dimethyl-cyclobutane tetracarboxylic dianhydride, and the fluorine-containing dianhydride monomer includes one or more of 4,4'-(hexafluoroisopropyl) bisphthalic anhydride and 3,4-dicarboxy-1,2,3,4-tetrahydro-6-trifluoromethyl-1-naphthalene butane dicarboxylic dianhydride.

[0035] The application also provides a negative photosensitive polyimide, which is prepared from the polyamic acid salt.

[0036] The application also provides a preparation method of the negative photosensitive polyimide, which comprises:

[0037] mixing the polyamic acid salt and a photoinitiator to obtain a photosensitive polyamic acid solution;

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

[0039] sequentially performing ultraviolet exposure and alkaline development on the polymer film to obtain a negative film with a target pattern;

[0040] performing heat imidization on the negative film 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-aminalkyl phenone.

[0042] and / or,

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

[0044] Preferably, the mixing time is 2-6h.

[0045] and / or,

[0046] The heating imidization is performed by programmed temperature, specifically including: heating from room temperature to 60-100℃ for no more than 4h, then heating to 100-140℃ for no more than 4h, then heating to 150-250℃ for no more than 4h, and finally heating to 250-350℃ for no more than 4h.

[0047] Preferably, the thickness of the polymer film is 5-150μm.

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

[0049] Compared with the prior art, the application has the following beneficial effects:

[0050] The application designs Ar group and takes vinylpyridine group as photosensitive group, and grafts it to polyamide acid chain to generate polyamide acid salt, the molecular polarizability of fluorine atom and aliphatic group in Ar group is low, which can reduce the dielectric constant of the polymer, and the hydroxyl-containing diamine can be used as synthetic monomer, and can realize alkaline development, therefore, the alkali-developable, low-dielectric negative photosensitive polyimide has important significance in the development of semiconductor. BRIEF DESCRIPTION OF DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments, and it should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as limiting the scope of the application.

[0052] Figure 1 The photoetching effect diagram of different line widths obtained in Example 1. DETAILED DESCRIPTION

[0053] The embodiments of the application will be described in detail below with specific examples, but those skilled in the art will understand that the following examples are only used to illustrate the application, and should not be regarded as limiting the scope of the application. The specific conditions are not specified in the examples, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be purchased on the market.

[0054] Example 1

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

[0056] Under N2 atmosphere, 15 mmol 3,3'-dihydroxybenzidine and 15 mmol 1,4-cyclohexanediamine were added into a three-neck flask, 100 ml N-methylpyrrolidone was added, after the diamine was completely dissolved, 15 mmol hexafluorodiphthalic anhydride and 15 mmol cyclobutane tetracarboxylic dianhydride were slowly added, then 60 mmol photosensitive 4-vinylpyridine was added, and the reaction was carried out for 2 h in the dark to obtain a polyamic acid salt solution.

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

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

[0059] 5 g of the photosensitive polyamic acid solution was uniformly coated on a clean and smooth silicon wafer or glass plate, most of the solvent was removed in a vacuum oven at 80°C to obtain a polymer film with a non-sticky surface; the film was exposed to a LED ultraviolet lamp with a center emission wavelength of 365 nm for a certain time, and then developed at room temperature with a tetramethylammonium hydroxide (TMAH) aqueous solution, followed by washing with deionized water to obtain a negative pattern.

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

[0061] Figure 1 A photoetching effect diagram of different line widths obtained from Example 1.

[0062] Example 2

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

[0064] Under N2 atmosphere, 15 mmol 3,3'-dihydroxybenzidine and 15 mmol 4,4'-diaminodicyclohexylmethane were added into a three-neck flask, 100 ml N,N-dimethylformamide was added, after the diamine was completely dissolved, 15 mmol hexafluorodiphthalic anhydride and 15 mmol 1,2,4,5-cyclohexane tetracarboxylic dianhydride were slowly added, then 60 mmol photosensitive 4-vinylpyridine was added, and the reaction was carried out for 2 h in the dark to obtain a polyamic acid salt solution.

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

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

[0067] 5g of the photosensitive polyamic acid solution was uniformly coated on a clean and smooth silicon wafer or glass plate, most of the solvent was removed in a vacuum oven at 80°C to obtain a polymer film with a non-sticky surface; the film was placed under a LED ultraviolet lamp with a center emission wavelength of 365 nm for a certain period of time, then developed at room temperature with a tetramethylammonium hydroxide (TMAH) aqueous solution, and then washed with deionized water to obtain a negative pattern.

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

[0069] Example 3

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

[0071] Under N2 atmosphere, 15 mmol of 3-hydroxyphenylamine and 15 mmol of 4,4'-diaminodicyclohexyl methane were added to a three-necked flask, 100 ml of N,N-dimethylacetamide was added, after the diamine was completely dissolved, 15 mmol of hexafluoro dianhydride and 15 mmol of 1,2,4,5-cyclohexane tetracarboxylic dianhydride were slowly added, then 60 mmol of photosensitive 4-vinylpyridine was added, and the reaction was carried out for 2h in the dark to obtain a polyamic acid salt solution.

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

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

[0074] 5g of the photosensitive polyamic acid solution was uniformly coated on a clean and smooth silicon wafer or glass plate, most of the solvent was removed in a vacuum oven at 80°C to obtain a polymer film with a non-sticky surface; the film was placed under a LED ultraviolet lamp with a center emission wavelength of 365 nm for a certain period of time, then developed at room temperature with a tetramethylammonium hydroxide (TMAH) aqueous solution, and then washed with deionized water to obtain a negative pattern.

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

[0076] Comparative Example 1

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

[0078] Under N2 atmosphere, 5 mmol 3,3'-dihydroxybenzidine and 15 mmol 1,4-cyclohexanediamine were added into a three-necked flask, 100 ml N-methylpyrrolidone was added, after the diamine was completely dissolved, 15 mmol hexafluorodiphthalic anhydride and 5 mmol cyclobutane tetracarboxylic dianhydride were slowly added, then 40 mmol photosensitive 4-vinylpyridine was added, and the reaction was carried out for 2 h in the dark to obtain a polyamic acid salt solution.

[0079] This comparative example provides a negative photosensitive polyimide, which is prepared as follows:

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

[0081] 5 g of the photosensitive polyamic acid solution was uniformly coated on a clean and smooth silicon wafer or glass plate, most of the solvent was removed in a vacuum oven at 80°C to obtain a polymer film with a non-sticky surface; the film was exposed to a LED ultraviolet lamp with a center emission wavelength of 365 nm for a certain time, and then developed at room temperature with a tetramethylammonium hydroxide (TMAH) aqueous solution, followed by washing with deionized water to obtain a negative pattern.

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

[0083] Comparative Example 2

[0084] This comparative example provides a polyamic acid salt, which is prepared as follows:

[0085] Under N2 atmosphere, 15 mmol 3,3'-dihydroxybenzidine and 5 mmol 4,4'-diaminodicyclohexylmethane were added into a three-necked flask, 100 ml N,N-dimethylformamide was added, after the diamine was completely dissolved, 15 mmol hexafluorodiphthalic anhydride and 5 mmol 1,2,4,5-cyclohexane tetracarboxylic dianhydride were slowly added, then 40 mmol photosensitive 4-vinylpyridine was added, and the reaction was carried out for 2 h in the dark to obtain a polyamic acid salt solution.

[0086] This comparative example provides a negative photosensitive polyimide, which is prepared as follows:

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

[0088] 5g of the photosensitive polyamic acid solution was uniformly coated on a clean and smooth silicon wafer or glass plate, most of the solvent was removed in a vacuum oven at 80°C to obtain a polymer film with a non-sticky surface; the film was placed under a LED ultraviolet lamp with a center emission wavelength of 365 nm for a certain period of time, then developed at room temperature with a tetramethylammonium hydroxide (TMAH) aqueous solution, and then washed 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, 300°C / 2h, and finally a negative photosensitive polyimide pattern was obtained.

[0090] Comparative Example 3

[0091] This comparative example provides a polyamic acid salt, which is prepared as follows:

[0092] Under N2 atmosphere, 15 mmol of 3-hydroxyphenylamine and 15 mmol of 4,4'-diaminodicyclohexyl methane were added to a three-necked flask, 100 ml of N,N-dimethylacetamide was added thereto, after the diamine was completely dissolved, 15 mmol of hexafluoro dianhydride and 15 mmol of 1,2,4,5-cyclohexane tetracarboxylic dianhydride were slowly added, then 60 mmol of photosensitive dimethylaminoethyl methacrylate was added, and the reaction was carried out for 2h in the dark to obtain a polyamic acid salt solution.

[0093] This comparative example provides a negative photosensitive polyimide, which is prepared as follows:

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

[0095] 5g of the photosensitive polyamic acid solution was uniformly coated on a clean and smooth silicon wafer or glass plate, most of the solvent was removed in a vacuum oven at 80°C to obtain a polymer film with a non-sticky surface; the film was placed under a LED ultraviolet lamp with a center emission wavelength of 365 nm for a certain period of time, then developed at room temperature with a tetramethylammonium hydroxide (TMAH) aqueous solution, and then washed 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, 300°C / 2h, and finally a negative photosensitive polyimide pattern was obtained.

[0097] The photosensitive sensitivity, 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 Photosensitivity (mJ / cm 2 ) Resolution (pm) 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 application has more excellent performance, increasing the content of hydroxyl groups is beneficial to alkaline development, the photosensitive sensitivity can reach 460 mJ / cm 2 , the resolution can reach 20 mu m, increasing the content of fat and fluorine groups can reduce the dielectric constant of PI, and the minimum is 2.68.

[0101] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A polyamic acid salt, characterized in that, Its general structural formula is: ； Ar1 is selected from any of the following structures: , Ar2 is selected from any of the following structures: 、 ； Ar3 is selected from any of the following structures: 、 ； Ar4 is selected from the following structure: ； R3N is selected from any one or more of the following structures: ； m and n are independent positive integers; The method for preparing the polyamate includes: A first reaction is carried out on diamine monomer and dianhydride monomer under a protective atmosphere to obtain a polyamic acid solution. Then, a photosensitive vinylpyridine compound is added, and a second reaction is carried out in the dark to obtain the polyamic acid salt. The molar ratio of the diamine monomer to the dianhydride monomer is 1:(1.05~1.10); the diamine monomer includes hydroxyl-containing diamine monomers and alicyclic diamine monomers, and the dianhydride monomer includes alicyclic dianhydride monomers and fluorine-containing dianhydride monomers; the molar ratio of the dianhydride monomer to the photosensitive vinylpyridine compound is 1:(2.0-2.1); the photosensitive vinylpyridine compound includes one or more of 4-vinylpyridine, 3-vinylpyridine, and methylvinylpyridine; In the diamine monomer, the molar content of the hydroxyl-containing diamine monomer is 10%~25%; in the dianhydride monomer, the molar content of the fluorine-containing dianhydride monomer is 10%~25%; the hydroxyl-containing diamine monomer is selected from 3,3'-dihydroxybenzidine or 3-hydroxybenzidine; the alicyclic diamine monomer is selected from 1,4-cyclohexanediamine or 4,4'-diaminodicyclohexylmethane; the alicyclic dianhydride monomer is selected from 1,2,4,5-cyclohexanetetracarboxylic dianhydride or cyclobutanetetracarboxylic dianhydride; and the fluorine-containing dianhydride monomer is 4,4'-(hexafluoroisopropyl)bisphthalic anhydride.

2. The polyamic acid salt according to claim 1, characterized in that, One or more of the following conditions must be met: (1) The temperature of the first reaction is -5℃ to 25℃, and the time is 8 to 24 h; (2) The second reaction is carried out at room temperature for 2 to 6 hours; (3) The system of the first reaction further includes an organic solvent, which includes one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.

3. A negatively photosensitive polyimide, characterized in that, Its raw materials include the polyamic acid salts described in claim 1 or 2.

4. A method for preparing the negatively photosensitive polyimide according to claim 3, characterized in that, include: The polyamic acid salt and the photoinitiator are mixed to obtain a photosensitive polyamic acid solution; The photosensitive polyamic acid solution is applied to a substrate and dried to obtain a polymer film. The polymer film is subjected to UV exposure and alkaline development in sequence to obtain a negative film with the target pattern; The negative film is heated and imidized to obtain the negative photosensitive polyimide.

5. The method for preparing negatively photosensitive polyimide according to claim 4, characterized in that, The photoinitiator includes one or more of the following: bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, Michlechone, benzophenone, 2,4-dihydroxybenzophenone, benzoin, benzoin dimethyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, α,α-diethoxyacetophenone, α-hydroxyalkylphenyl ketone, and α-aminealkylbenzene; And / or, The amount of photoinitiator is 0.2 to 10 wt% of the polyamic acid salt.

6. The method for preparing negatively photosensitive polyimide according to claim 4, characterized in that, The mixing time is 2-6 hours; And / or, The heating imidization is carried out using a programmed temperature increase, specifically including: heating from room temperature to 60~100℃ and holding for no more than 4 hours, then heating to 100~140℃ and holding for no more than 4 hours, then heating to 150~250℃ and holding for no more than 4 hours, and finally heating to 250~350℃ and holding for no more than 4 hours.

7. The method for preparing negatively photosensitive polyimide according to any one of claims 4-6, characterized in that, The thickness of the polymer film is 5-150 μm.

8. An electronic product, characterized in that, Includes the negative photosensitive polyimide as described in claim 3.

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