A polyimide film stripping solution, a preparation method and application thereof

Abstract

The present application relates to a kind of polyimide film stripping liquid and its preparation method and application, the component of the polyimide film stripping liquid includes by mass percentage: strong polar solvent 60-80%, alcohol ether solvent 10-30%, organic strong base 3-10%, surfactant 0.001-0.1%, metal resist 0.1-1%.Wherein organic strong base can be split into small fragments by polyimide polymer, help to speed up stripping speed and improve stripping effect;Wherein strong polar solvent and alcohol ether solvent are used in combination, mixed solvent has better swelling and demolding effect to polyimide film;Wherein surfactant can reduce the surface tension of solvent with very low addition amount, improve stripping effect of stripping liquid;Metal resist reduces the damage and corrosion situation of stripping liquid to metal on substrate.The above-mentioned components are synergized with specific mass ratio, and can quickly and completely strip polyimide film on substrate at room temperature, and will not cause damage and corrosion situation to metal on substrate.

Description

Technical Field

[0001] This invention belongs to the field of stripping liquid technology, and relates to a polyimide film (PI film) stripping liquid, its preparation method and application, and in particular to a polyimide film (PI film) stripping liquid with fast stripping speed, warm stripping conditions and no adhesive residue, its preparation method and application. Background Technology

[0002] PI film, or polyimide film, is usually obtained by polycondensation of aromatic dianhydride and aromatic diamine in a strongly polar solvent, followed by casting / coating to form a film, and then imidization. It has excellent high and low temperature resistance, and can withstand high temperatures above 350°C for short periods of time. In addition, its dielectric constant is about 3.4, which provides good insulation properties.

[0003] In the semiconductor field, PI films are often used as dielectric layers to meet the requirements of high temperature resistance and reliable isolation between circuits during manufacturing processes. In the display panel field, PI materials are used as alignment films to guide the alignment of liquid crystal molecules. In the aerospace field, polyimide possesses excellent high temperature resistance, high strength, and chemical corrosion resistance, meeting the requirements of aerospace equipment operating in extreme environments such as high temperature, high pressure, and strong radiation, thus improving the reliability and durability of the equipment. It is evident that PI materials have mature applications in multiple fields.

[0004] Because defects (such as insufficient adhesive, particle contamination, or bubbles after curing) may occur during the coating and subsequent curing processes of PI liquid, it is necessary to peel off the defective PI film in order to reduce substrate loss. Existing stripping solutions have problems such as slow stripping speed and harsh stripping conditions, and may corrode the contacted metal circuits or introduce metal ions that lead to insulation failure. In addition, in the more specialized field of temporary bonding in advanced semiconductor packaging, specially modified PI films can be used as laser release materials. After debonding, there are usually adhesive residues, which can interfere with the normal operation of subsequent processes.

[0005] CN117369226A discloses a corrosion-resistant modified PI film stripping solution and its preparation method. The PI film stripping solution comprises the following components by mass percentage: 5-10% N-methylpyrrolidone, 5-10% N,N-dimethylformamide, 30-50% diethylene glycol butyl ether, 5-10% monoethanolamine, 0.1-0.5% potassium hydroxide, 1-2% metal protectant, 0.5-1% additives, and the balance being pure water. The addition of potassium hydroxide in this stripping solution allows potassium ions to penetrate into the substrate during the PI film stripping process, which are difficult to remove by water washing, posing a risk to the insulation reliability of the substrate's dielectric layer.

[0006] CN113741159A discloses a PI membrane stripping solution, which, by weight percentage, is composed of the following components: 10-20% organic alcohol amines, 4-12% quaternary ammonium bases, 45-60% alcohol organic solvents, 0.5-2.0% nonionic surfactants, and the balance being pure water. This PI membrane stripping solution requires harsh stripping conditions, necessitating heating at 45-65°C and a long stripping time, requiring immersion for 25-35 minutes.

[0007] Therefore, it is essential to develop a stripping solution that can rapidly peel off PI films at room temperature without damaging or corroding materials such as metals, and without leaving any metal ions after the stripping process. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a polyimide film (PI film) release agent, its preparation method, and its application, particularly a polyimide film (PI film) release agent with fast release speed, warm release conditions, and no adhesive residue, as well as its preparation method and application.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a polyimide film stripping solution, wherein the components of the polyimide film stripping solution, by mass percentage, include: 60-80% strong polar solvent, 10-30% alcohol ether solvent, 3-10% strong organic base, 0.001-0.1% surfactant, and 0.1-1% metal resist.

[0011] This invention develops a novel polyimide film release solution formulation. A strong organic base attacks specific imide bonds, breaking the polyimide polymer into smaller fragments, thus accelerating the release speed and improving the release effect. A combination of a highly polar solvent and an alcohol ether solvent provides better swelling and release properties for the polyimide film. A surfactant, added in extremely low amounts, reduces the surface tension of the solvent, enhancing the release effect. A metal resist reduces damage and corrosion to the metal on the substrate. These components, in specific mass ratios, work synergistically to rapidly and completely release the polyimide film from the substrate at room temperature without damaging or corroding the metal.

[0012] The mass percentage of the strongly polar solvent can be selected from 60%, 63%, 65%, 68%, 70%, 75%, 78%, 80%, etc.; the mass percentage of the alcohol ether solvent can be selected from 10%, 13%, 15%, 18%, 20%, 25%, 28%, 30%, etc.; the mass percentage of the organic strong base can be selected from 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.; the mass percentage of the surfactant... The content can be selected from 0.001%, 0.003%, 0.005%, 0.008%, 0.01%, 0.05%, 0.08%, 0.1%, etc.; the mass percentage content of the metal corrosion resist can be selected from 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc.; other specific values ​​within the above ranges can also be selected, and will not be elaborated here.

[0013] Preferably, the highly polar solvent includes any one or a combination of at least two of N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropionamide, dimethyl sulfoxide, N-methylpyrrolidone or 1,3-dimethyl-2-imidazolone.

[0014] Preferably, the alcohol ether solvent includes any one or a combination of at least two of ethylene glycol monobutyl ether, ethylene glycol tert-butyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether, propylene glycol methyl ether acetate, or propylene glycol methyl ether propionate; preferably, a combination of propylene glycol methyl ether and propylene glycol methyl ether acetate.

[0015] Based on the potential interaction between highly polar solvents and alcohol ether solvents in swelling and removing polyimide films, the effect is better when the specific types of solvents mentioned above are selected. Furthermore, the removal efficiency of the polyimide film is further improved when the alcohol ether solvent is a combination of propylene glycol methyl ether and propylene glycol methyl ether acetate.

[0016] Preferably, the strong organic base includes any one or a combination of at least two of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetramethylguanidine, tetraethylguanidine, or tetrapropylguanidine; more preferably, a combination of tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetramethylguanidine.

[0017] The aforementioned specific types of strong organic bases are superior in splitting polyimide polymers, accelerating the peeling speed, and improving the peeling effect. Among them, the combined use of tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetramethylguanidine further enhances the peeling efficiency compared to other types.

[0018] Preferably, the surfactant comprises any one or a combination of at least two of the following: sodium fatty acid methyl ester ethoxylate sulfonate, monolauryl phosphate, hexadecyltrimethylammonium bromide, dodecyl dimethyl benzyl ammonium chloride, dioctadecyl dimethyl ammonium chloride, or glyceryl monostearate.

[0019] Preferably, the metal resist comprises any one or a combination of at least two of benzotriazole, ethylenediaminetetraacetic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, or aminetrimethylenephosphonic acid.

[0020] Preferably, the polyimide film stripping solution comprises, by mass percentage: 65-75% strong polar solvent, 16-24% alcohol ether solvent, 5-8% strong organic base, 0.01-0.05% surfactant, and 0.3-0.8% metal resist.

[0021] Preferably, the polyimide film stripping solution further comprises, by mass percentage, 0.1-0.5% of a penetration enhancer; the mass percentage of the penetration enhancer can be selected from 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, etc.; other specific values ​​within this range can also be selected, and will not be elaborated here.

[0022] Furthermore, adding a penetration enhancer to the stripping solution formulation can improve the penetration effect of each component in the polyimide membrane, enhance the effectiveness of each component, and ultimately improve the stripping performance of the polyimide membrane. A more preferred combination of polyethyleneimine, hexamethylenetetramine, and polyethylene glycol as a penetration enhancer yields the best results.

[0023] Preferably, the penetration enhancer comprises any one or a combination of at least two of polyethyleneimine, hexamethylenetetramine, or polyethylene glycol; more preferably, a combination of polyethyleneimine, hexamethylenetetramine, and polyethylene glycol.

[0024] In a second aspect, the present invention provides a method for preparing the polyimide film stripping solution according to the first aspect, the method comprising:

[0025] The highly polar solvent, alcohol ether solvent, strong organic base, surfactant, metal resist and optional penetration enhancer are stirred and mixed at 10-50℃ (e.g. 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃, 50℃, etc.) for 3-8 hours (e.g. 3h, 4h, 5h, 6h, 7h, 8h, etc.), and then filtered to obtain the final product.

[0026] The preparation method of the polyimide film stripping liquid involved in this invention is simple and easy to operate, and can achieve industrial-scale production.

[0027] Thirdly, the present invention provides the application of the polyimide film stripping liquid according to the first aspect in stripping polyimide films on the surface of a substrate.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] This invention develops a novel polyimide film release solution formulation. A strong organic base attacks specific imide bonds, breaking the polyimide polymer into smaller fragments, thus accelerating the release speed and improving the release effect. A combination of a highly polar solvent and an alcohol ether solvent provides better swelling and release properties for the polyimide film. A surfactant, added in extremely low amounts, reduces the surface tension of the solvent, enhancing the release effect. A metal resist reduces damage and corrosion to the metal on the substrate. These components, in specific mass ratios, work synergistically to rapidly and completely release the polyimide film from the substrate at room temperature without damaging or corroding the metal. Detailed Implementation

[0030] To further illustrate the technical means and effects of the present invention, the following describes the technical solution of the present invention in conjunction with preferred embodiments of the present invention. However, the present invention is not limited to the scope of the embodiments.

[0031] Example 1

[0032] This embodiment provides a polyimide film stripping solution, the components of which, by mass percentage, include: 71.45% N,N-dimethylacetamide, 10% propylene glycol methyl ether, 10% propylene glycol methyl ether acetate, 3% tetramethylguanidine, 2% tetramethylammonium hydroxide, 3% tetraethylammonium hydroxide, 0.05% monolauryl phosphate, 0.3% benzotriazole, and 0.2% ethylenediaminetetraacetic acid. Its preparation method is as follows:

[0033] Start the reactor stirring and set the speed to 600 rpm; add the above components according to the ratio, stir and mix at 25°C for 5 hours, and transfer the above liquid to a special filtration vessel for filtration to obtain the final product.

[0034] Example 2

[0035] This embodiment provides a polyimide film stripping solution, the components of which, by weight percentage, include: 65.17% dimethyl sulfoxide, 12% propylene glycol methyl ether, 12% propylene glycol methyl ether acetate, 4% tetrapropylguanidine, 4% tetramethylammonium hydroxide, 2% tetrapropylammonium hydroxide, 0.03% dodecyl dimethyl benzyl ammonium chloride, and 0.8% ethylenediaminetetraacetic acid. Its preparation method is as follows:

[0036] Start the reactor stirring and set the speed to 600 rpm; add the above components according to the ratio, stir and mix at 30°C for 4 hours, and transfer the above liquid to a special filtration vessel for filtration to obtain the final product.

[0037] Example 3

[0038] This embodiment provides a polyimide film stripping solution, the components of which, by mass percentage, include: 41.16% N,N-dimethylformamide, 30% N,N-dimethylacetamide, 10% propylene glycol methyl ether, 8% propylene glycol methyl ether acetate, 10% tetrapropylguanidine, 0.04% glyceryl monostearate, and 0.8% ethylenediaminetetramethylenephosphoric acid. Its preparation method is as follows:

[0039] Start the stirring in the reactor and set the speed to 600 rpm; add the above components according to the ratio, stir and mix at 20°C for 7 hours, and transfer the above liquid to a special filtration vessel for filtration to obtain the final product.

[0040] Example 4

[0041] This embodiment provides a polyimide film stripping solution, the only difference from Example 1 being that 10% propylene glycol methyl ether and 10% propylene glycol methyl ether acetate are replaced with 20% propylene glycol methyl ether, while other components and contents remain unchanged. The preparation method is the same as in Example 1.

[0042] Example 5

[0043] This embodiment provides a polyimide film stripping solution, the only difference from Example 1 being that 10% propylene glycol methyl ether and 10% propylene glycol methyl ether acetate are replaced with 20% propylene glycol methyl ether acetate, while other components and contents remain unchanged. The preparation method is the same as in Example 1.

[0044] Example 6

[0045] This embodiment provides a polyimide film stripping solution, the only difference from that of Example 1 being the replacement of 3% tetramethylguanidine, 2% tetramethylammonium hydroxide, and 3% tetraethylammonium hydroxide with 5% tetramethylguanidine and 3% tetramethylammonium hydroxide, while the other components and their contents remain unchanged. The preparation method is the same as in Example 1.

[0046] Example 7

[0047] This embodiment provides a polyimide film stripping solution, the only difference from that of Example 1 being the replacement of 3% tetramethylguanidine, 2% tetramethylammonium hydroxide, and 3% tetraethylammonium hydroxide with 4% tetramethylguanidine and 4% tetraethylammonium hydroxide, while the other components and their contents remain unchanged. The preparation method is the same as in Example 1.

[0048] Example 8

[0049] This embodiment provides a polyimide film stripping solution, the only difference from that of Example 1 being the replacement of 3% tetramethylguanidine, 2% tetramethylammonium hydroxide, and 3% tetraethylammonium hydroxide with 5% tetramethylammonium hydroxide and 3% tetraethylammonium hydroxide, while the other components and their contents remain unchanged. The preparation method is the same as in Example 1.

[0050] Example 9

[0051] This embodiment provides a polyimide film stripping solution, the only difference from that of Example 1 being the replacement of 0.3% benzotriazole and 0.2% ethylenediaminetetraacetic acid with 0.5% benzotriazole, while the other components and their contents remain unchanged. The preparation method is the same as in Example 1.

[0052] Example 10

[0053] This embodiment provides a polyimide film stripping solution, the only difference from Example 1 being that 0.3% benzotriazole and 0.2% ethylenediaminetetraacetic acid are replaced with 0.5% ethylenediaminetetraacetic acid, while other components and contents remain unchanged. The preparation method is the same as in Example 1.

[0054] Example 11

[0055] This embodiment provides a polyimide film stripping solution, the only difference from Example 1 being the addition of 0.5% polyethylene glycol 200, with a corresponding reduction of 0.5% in the content of N,N-dimethylacetamide, while other components and their contents remain unchanged. The preparation method is the same as in Example 1.

[0056] Comparative Example 1

[0057] This comparative example provides a polyimide film stripping solution, the only difference from Example 1 being the absence of a strongly polar solvent. Specifically, 71.45% N,N-dimethylacetamide, 10% propylene glycol methyl ether, and 10% propylene glycol methyl ether acetate are replaced with 46.45% propylene glycol methyl ether and 45% propylene glycol methyl ether acetate, while other components and their contents remain unchanged. The preparation method is the same as in Example 1.

[0058] Comparative Example 2

[0059] This comparative example provides a polyimide film stripping solution, the only difference from Example 1 being the absence of alcohol ether solvents. Specifically, 71.45% N,N-dimethylacetamide, 10% propylene glycol methyl ether, and 10% propylene glycol methyl ether acetate are replaced with 91.45% N,N-dimethylacetamide, while other components and their contents remain unchanged. The preparation method is the same as in Example 1.

[0060] Comparative Example 3

[0061] This comparative example provides a polyimide film stripping solution, the only difference between which is the composition of Example 1 is the absence of a strong organic base. The reduced amount is made up by N,N-dimethylacetamide, while the other components and their contents remain unchanged. The preparation method is the same as in Example 1.

[0062] Comparative Example 4

[0063] This comparative example provides a polyimide film stripping solution, the only difference from Example 1 being the absence of a surfactant. The reduced amount is compensated by N,N-dimethylacetamide, while the other components and their contents remain unchanged. The preparation method is the same as in Example 1.

[0064] Comparative Example 5

[0065] This comparative example provides a polyimide film stripping solution, the only difference between which is the metal resist agent and that of Example 1; the other components and their contents remain unchanged. The preparation method is the same as in Example 1.

[0066] Test case

[0067] Glass substrates (4-inch circular glass) coated with a 1μm thick PI film (made from laser emission material WLPRL420 provided by Shenzhen Huaxun Semiconductor Materials Co., Ltd., through coating, pre-baking at 90℃, and high-temperature curing at 380℃), and 10mm×10mm×0.4mm copper and aluminum sheets (both polished sheets with an initial roughness of 5nm) were immersed in the stripping solutions prepared in Examples 1-11 and Comparative Examples 1-5, respectively. After immersion at 25℃ for 10min or 25min, they were rinsed with pure water for 3min and then dried with nitrogen. The maximum remaining thickness of the PI film and the surface roughness of the copper and aluminum sheets were measured using a profilometer. The test results for 25min are shown in Table 1, and the test results for 10min are shown in Table 2.

[0068] Table 1

[0069]

[0070]

[0071] As shown in Table 1, compared with Comparative Examples 1-4, the stripping liquids involved in Examples 1-11 have significantly better stripping effects on polyimide films at room temperature, with no or almost no residual adhesive. Compared with Comparative Example 5, the stripping liquids involved in Examples 1-11 do not cause corrosion of the metal substrate when stripping polyimide films on metal substrates at room temperature.

[0072] Table 2

[0073]

[0074]

[0075] As shown in Table 2, compared with the data in Table 1, the stripping solutions involved in Examples 1-11 exhibit significantly superior stripping effects on polyimide films at room temperature compared to Comparative Examples 1-4, even with shorter soaking times. Example 11 showed the best stripping effect with no residual adhesive. The data comparison between different examples also indicates that the formulation of alcohol ether solvents and organic strong alkalis also affect the stripping efficiency of polyimide films to some extent. Furthermore, even with shorter soaking times, the stripping solutions involved in Examples 1-11, compared to Comparative Example 5, do not cause corrosion of the metal substrate when stripping polyimide films from metal substrates at room temperature.

[0076] The applicant declares that the technical solution of this invention is illustrated by the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

[0077] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0078] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A polyimide film stripping solution, characterized in that, The polyimide film stripping solution comprises, by weight percentage: 60-80% strong polar solvent, 10-30% alcohol ether solvent, 3-10% strong organic base, 0.001-0.1% surfactant, and 0.1-1% metal corrosion inhibitor; The alcohol ether solvents include a combination of propylene glycol methyl ether and propylene glycol methyl ether acetate; The organic strong base includes a combination of tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetramethylguanidine.

2. The polyimide film stripping solution according to claim 1, characterized in that, The strongly polar solvent includes any one or a combination of at least two of N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropionamide, dimethyl sulfoxide, N-methylpyrrolidone, or 1,3-dimethyl-2-imidazolone.

3. The polyimide film stripping solution according to claim 1, characterized in that, The surfactant includes any one or a combination of at least two of the following: sodium fatty acid methyl ester ethoxylate sulfonate, monolauryl phosphate, hexadecyltrimethylammonium bromide, dodecyl dimethyl benzyl ammonium chloride, dioctadecyl dimethyl ammonium chloride, or glyceryl monostearate.

4. The polyimide film stripping solution according to claim 1, characterized in that, The metal corrosion inhibitor includes any one or a combination of at least two of benzotriazole, ethylenediaminetetraacetic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, or aminetrimethylenephosphonic acid.

5. The polyimide film stripping solution according to claim 1, characterized in that, The polyimide film stripping solution comprises, by mass percentage: 65-75% strong polar solvent, 16-24% alcohol ether solvent, 5-8% strong organic base, 0.01-0.05% surfactant, and 0.3-0.8% metal resist.

6. The polyimide film stripping solution according to claim 1, characterized in that, The polyimide membrane stripping solution further comprises, by weight percentage: 0.1-0.5% penetration enhancer.

7. The polyimide film stripping solution according to claim 6, characterized in that, The penetration enhancer includes any one or a combination of at least two of polyethyleneimine, hexamethylenetetramine, or polyethylene glycol.

8. The method for preparing the polyimide film stripping solution according to any one of claims 1-5, characterized in that, The preparation method includes: The highly polar solvent, alcohol ether solvent, strong organic base, surfactant, and metal resist are stirred and mixed at 10-50℃ for 3-8 hours, and then filtered to obtain the final product.

9. The method for preparing the polyimide film stripping solution according to claim 6 or 7, characterized in that, The preparation method includes: stirring and mixing a strong polar solvent, an alcohol ether solvent, a strong organic base, a surfactant, a metal corrosion inhibitor, and a penetration enhancer at 10-50°C for 3-8 h, and then filtering to obtain the final product.

10. The use of the polyimide film stripping solution according to any one of claims 1-7 in stripping polyimide films from substrate surfaces.

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