Polyimide film stripping liquid as well as preparation method and application thereof

Abstract

The invention relates to a polyimide film stripping liquid as well as a preparation method and application thereof. The polyimide film stripping liquid comprises the following components in percentage by mass: 60-80% of a strong polar solvent, 10-30% of an alcohol ether solvent, 3-10% of organic strong alkali, 0.001-0.1% of a surfactant and 0.1-1% of a metal resist. Wherein the organic strong base can be used for splitting polyimide macromolecules into small fragments, so that the stripping speed is increased and the stripping effect is improved; wherein the strong polar solvent and the alcohol ether solvent are combined for use, and the mixed solvent has better swelling and demolding effects on the polyimide film; wherein the surface tension of the solvent can be reduced and the stripping effect of the stripping liquid can be improved by an extremely low addition amount of the surfactant; the metal resist reduces the damage and corrosion of the stripping liquid to the metal on the substrate. The components are matched with one another according to a specific mass ratio and have a synergistic effect, a polyimide film on a base material can be rapidly and completely stripped under the condition of normal temperature, and metal on the base material cannot be damaged or corroded.

Description

Technical Field

[0001] The present invention belongs to the technical field of stripping fluids, and relates to a polyimide film (PI film) stripping fluid, a preparation method and an application thereof, and in particular to a polyimide film (PI film) stripping fluid with fast stripping speed, warm stripping conditions and no residual adhesive, and a preparation method and an application thereof. Background Art

[0002] PI film, or polyimide film, is usually obtained by polycondensing aromatic dianhydrides and aromatic diamines in a strong polar solvent and casting / coating them into films, followed by imidization. It has excellent high and low temperature resistance and can withstand high temperatures above 350°C for a short time. In addition, its dielectric constant is about 3.4, and it has good insulation properties.

[0003] In the semiconductor field, PI film is often used as a dielectric layer to meet the requirements of high temperature resistance and reliable isolation between lines in the process. In the display panel field, PI material needs to be used as an alignment film to guide the arrangement direction of liquid crystal molecules. In the aerospace field, polyimide has excellent high temperature resistance, high strength and chemical corrosion resistance, which can meet the use requirements of aerospace equipment in extreme environments such as high temperature, high pressure, and strong radiation, and improve the reliability and durability of the equipment. It can be seen that PI materials have mature applications in many fields.

[0004] Since the PI liquid has a probability of having defects (such as lack of glue, particle contamination or bubbles after curing, etc.) during the coating and subsequent curing process, in order to reduce the loss of the substrate, the bad PI film needs to be stripped off. The existing stripping liquid has a slow stripping speed and harsh stripping conditions, and may corrode the metal circuits it contacts, or introduce metal ions to cause insulation failure. In addition, in the more subdivided temporary bonding field of semiconductor advanced packaging, specifically modified PI films can be used as laser release materials. After debonding, there will usually be residual glue left, and the presence of residual glue will interfere with the normal progress of subsequent processes.

[0005] CN117369226A discloses a corrosion-resistant modified PI film stripping solution and a preparation method thereof, wherein 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 protective agent, 0.5-1% additive, and the balance is pure water. Potassium hydroxide is added to the stripping solution, and during the stripping process of the PI film, potassium ions will penetrate into the substrate and are difficult to be removed by water washing, which poses a risk to the insulation reliability of the substrate dielectric layer.

[0006] CN113741159A discloses a PI film stripping solution, which is prepared from the following components by weight percentage: 10-20% organic alcohol amine, 4-12% quaternary ammonium base, 45-60% alcohol organic solvent, 0.5-2.0% non-ionic surfactant and pure water to make up the balance. The stripping conditions of the PI film stripping solution are harsh, and it needs to be heated at 45-65°C, and the stripping time is long, requiring immersion for 25-35 minutes.

[0007] Therefore, it is very necessary to develop a stripping solution that can quickly strip the PI film at room temperature without damaging or corroding metals and other materials and without leaving any metal ions after stripping. Summary of the invention

[0008] In view of the deficiencies in the prior art, the object of the present invention is to provide a polyimide film (PI film) stripping solution and a preparation method and application thereof, and in particular to provide a polyimide film (PI film) stripping solution with a fast stripping speed, warm stripping conditions and no residual adhesive and a preparation method and application thereof.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

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

[0011] The present invention has developed a new polyimide film stripping solution formula, in which the organic strong base can attack specific imide bonds and split the polyimide polymer into small fragments, which helps to speed up the stripping speed and improve the stripping effect; the strong polar solvent and alcohol ether solvent are used in combination, and the mixed solvent has a better swelling and demolding effect on the polyimide film; the surfactant can reduce the surface tension of the solvent with a very low addition amount, and improve the stripping effect of the stripping solution; the metal anti-corrosion agent reduces the damage and corrosion of the stripping solution to the metal on the substrate. The above components cooperate with each other in a specific mass ratio, and synergistically enhance the effect, and can quickly and completely strip the polyimide film on the substrate under normal temperature conditions, and will not cause damage and corrosion to the metal on the substrate.

[0012] The mass percentage of the strong 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 can be selected from 10%, 13%, 15%, 18%, 20%, 25%, 28%, 30%, etc. The percentage content can be selected from 0.001%, 0.003%, 0.005%, 0.008%, 0.01%, 0.05%, 0.08%, 0.1% and the like; the mass percentage content of the metal anti-corrosion agent can be selected from 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% and the like; other specific point values ​​within the above numerical ranges can be selected, and they will not be described one by one here.

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

[0014] Preferably, the alcohol ether solvent includes any one 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, or a combination of at least two thereof; preferably, a combination of propylene glycol methyl ether and propylene glycol methyl ether acetate.

[0015] Based on the potential interaction between strong polar solvents and alcohol ether solvents in swelling and removing polyimide membranes, when the two are selected from the above specific types, the effect is better. And when the alcohol ether solvent is a combination of propylene glycol methyl ether and propylene glycol methyl ether acetate, the removal efficiency of the polyimide membrane is further improved.

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

[0017] The above-mentioned specific types of organic strong bases are better at splitting polyimide polymers, accelerating the stripping speed and improving the stripping effect. Among them, when tetramethylammonium hydroxide, tetraethylammonium hydroxide and tetramethylguanidine are used in combination, their stripping efficiency is further improved compared with other types.

[0018] Preferably, the surfactant includes any one or a combination of at least two of fatty acid methyl ester ethoxylate sodium sulfonate, monolauryl phosphate, hexadecyltrimethylammonium bromide, dodecyldimethylbenzylammonium chloride, dioctadecyldimethylammonium chloride or glyceryl monostearate.

[0019] Preferably, the metal resist comprises any one of benzotriazole, ethylenediaminetetraacetic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepenta(methylenephosphonic acid) or aminetri(methylenephosphonic acid) or a combination of at least two thereof.

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

[0021] Preferably, the components of the polyimide film stripping solution also include, in terms of 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 point values ​​within this numerical range can be selected, and they will not be described one by one here.

[0022] Furthermore, adding a penetration enhancer to the stripping solution formula can improve the penetration effect of each component in the polyimide film, improve the efficacy of each component, and ultimately improve the stripping effect of the polyimide film. More preferably, a combination of polyethyleneimine, hexamethylenetetramine and polyethylene glycol is used as a penetration enhancer, which has the best effect.

[0023] Preferably, the penetration enhancer comprises any one of polyethyleneimine, hexamethylenetetramine or polyethylene glycol, or a combination of at least two thereof; 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 preparation method comprising:

[0025] A strong polar solvent, an alcohol ether solvent, a strong organic base, a surfactant, a metal anti-corrosion agent and an optional penetration enhancer are stirred and mixed at 10-50°C (for example, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 50°C, etc.) for 3-8h (for example, 3h, 4h, 5h, 6h, 7h, 8h, etc.), and filtered to obtain.

[0026] The preparation method of the polyimide film stripping solution of the present invention is simple and easy to operate, and can realize industrialized large-scale production.

[0027] In a third aspect, the present invention provides use of the polyimide film stripping solution according to the first aspect in stripping a polyimide film from a surface of a substrate.

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

[0029] The present invention has developed a new polyimide film stripping solution formula, in which the organic strong base can attack specific imide bonds and split the polyimide polymer into small fragments, which helps to speed up the stripping speed and improve the stripping effect; the strong polar solvent and alcohol ether solvent are used in combination, and the mixed solvent has a better swelling and demolding effect on the polyimide film; the surfactant can reduce the surface tension of the solvent with a very low addition amount, and improve the stripping effect of the stripping solution; the metal anti-corrosion agent reduces the damage and corrosion of the stripping solution to the metal on the substrate. The above components cooperate with each other in a specific mass ratio, and synergistically enhance the effect, and can quickly and completely strip the polyimide film on the substrate under normal temperature conditions, and will not cause damage and corrosion to the metal on the substrate. DETAILED DESCRIPTION

[0030] In order to further explain the technical means and effects adopted by the present invention, the technical solution of the present invention is further described below in conjunction with the preferred embodiments of the present invention, but the present invention is not limited to the scope of the embodiments.

[0031] Example 1

[0032] This embodiment provides a polyimide film stripping solution, whose components, 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. The preparation method is as follows:

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

[0034] Example 2

[0035] This embodiment provides a polyimide film stripping solution, whose components, by mass 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% dodecyldimethylbenzyl ammonium chloride, and 0.8% ethylenediaminetetraacetic acid. The preparation method is as follows:

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

[0037] Example 3

[0038] This embodiment provides a polyimide film stripping solution, whose components, 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. The preparation method is as follows:

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

[0040] Example 4

[0041] This embodiment provides a polyimide film stripping solution, the components of which are different from those of embodiment 1 only in that 10% propylene glycol methyl ether and 10% propylene glycol methyl ether acetate are replaced with 20% propylene glycol methyl ether, and the other components and contents remain unchanged.

[0042] Example 5

[0043] This embodiment provides a polyimide film stripping solution, the components of which are different from those of embodiment 1 only in that 10% propylene glycol methyl ether and 10% propylene glycol methyl ether acetate are replaced with 20% propylene glycol methyl ether acetate, and the other components and contents remain unchanged.

[0044] Example 6

[0045] This embodiment provides a polyimide film stripping solution, the components of which are different from those of embodiment 1 only in that 3% tetramethylguanidine, 2% tetramethylammonium hydroxide, and 3% tetraethylammonium hydroxide are replaced with 5% tetramethylguanidine and 3% tetramethylammonium hydroxide, and the other components and contents remain unchanged. The preparation method is the same as that of embodiment 1.

[0046] Example 7

[0047] This embodiment provides a polyimide film stripping solution, the components of which differ from those of embodiment 1 only in that 3% tetramethylguanidine, 2% tetramethylammonium hydroxide, and 3% tetraethylammonium hydroxide are replaced with 4% tetramethylguanidine and 4% tetraethylammonium hydroxide, and the other components and contents remain unchanged. The preparation method is the same as that of embodiment 1.

[0048] Example 8

[0049] This embodiment provides a polyimide film stripping solution, the components of which are different from those of embodiment 1 only in that 3% tetramethylguanidine, 2% tetramethylammonium hydroxide, and 3% tetraethylammonium hydroxide are replaced with 5% tetramethylammonium hydroxide and 3% tetraethylammonium hydroxide, and the other components and contents remain unchanged. The preparation method is the same as that of embodiment 1.

[0050] Example 9

[0051] This embodiment provides a polyimide film stripping solution, the components of which are different from those of embodiment 1 only in that 0.3% benzotriazole and 0.2% ethylenediaminetetraacetic acid are replaced with 0.5% benzotriazole, and the other components and contents remain unchanged.

[0052] Example 10

[0053] This embodiment provides a polyimide film stripping solution, the components of which are different from those of embodiment 1 only in that 0.3% benzotriazole and 0.2% ethylenediaminetetraacetic acid are replaced with 0.5% ethylenediaminetetraacetic acid, and the other components and contents remain unchanged.

[0054] Embodiment 11

[0055] This embodiment provides a polyimide film stripping solution, the components of which are different from those of embodiment 1 only in that 0.5% polyethylene glycol 200 is further added, the content of N,N-dimethylacetamide is correspondingly reduced by 0.5%, and other components and contents remain unchanged. The preparation method is the same as that of embodiment 1.

[0056] Comparative Example 1

[0057] This comparative example provides a polyimide film stripping solution, the components of which differ from those of Example 1 only in the lack of a strong polar solvent, that is, 71.45% of N,N-dimethylacetamide, 10% of propylene glycol methyl ether, and 10% of propylene glycol methyl ether acetate are replaced with 46.45% of propylene glycol methyl ether and 45% of propylene glycol methyl ether acetate, and the other components and contents remain unchanged. The preparation method is referred to Example 1.

[0058] Comparative Example 2

[0059] This comparative example provides a polyimide film stripping solution, the components of which differ from those of Example 1 only in the lack of alcohol ether solvents, that is, 71.45% of N,N-dimethylacetamide, 10% of propylene glycol methyl ether, and 10% of propylene glycol methyl ether acetate are replaced with 91.45% of N,N-dimethylacetamide, and the other components and contents remain unchanged. The preparation method is referred to Example 1.

[0060] Comparative Example 3

[0061] This comparative example provides a polyimide film stripping solution, the components of which differ from those of Example 1 only in that an organic strong base is missing, the reduced amount of which is supplemented by N,N-dimethylacetamide, and the other components and contents remain unchanged. The preparation method is the same as that of Example 1.

[0062] Comparative Example 4

[0063] This comparative example provides a polyimide film stripping solution, the components of which differ from those of Example 1 only in the lack of surfactant, the reduced amount of which is supplemented by N,N-dimethylacetamide, and the other components and contents remain unchanged. The preparation method is the same as that of Example 1.

[0064] Comparative Example 5

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

[0066] Test Case

[0067] A glass substrate (4-inch round glass) coated with a 1 μm thick PI film (made by coating, pre-baking at 90°C and curing at 380°C with the laser release material WLPRL420 provided by Shenzhen Huaxun Semiconductor Materials Co., Ltd.), a 10mm×10mm×0.4mm copper sheet and an aluminum sheet (both polished sheets, with an initial roughness of 5nm) were immersed in the stripping solution prepared in Examples 1-11 and Comparative Examples 1-5, respectively, and then rinsed with pure water for 3 minutes after being immersed at 25°C for 10 minutes or 25 minutes, and then dried with nitrogen. The maximum remaining thickness of the PI film and the surface roughness of the copper sheet and the aluminum sheet were tested using a step profiler. The test results for 25 minutes are shown in Table 1, and the test results for 10 minutes are shown in Table 2.

[0068] Table 1

[0069]

[0070]

[0071] It can be seen from the data results in Table 1 that, compared with comparative examples 1-4, the stripping liquid involved in Examples 1-11 has a significantly excellent stripping effect on the polyimide film at room temperature, with no residual glue or basically no residual glue; compared with comparative example 5, when the stripping liquid involved in Examples 1-11 is used to strip the polyimide film on the metal substrate at room temperature, the metal substrate will not be corroded.

[0072] Table 2

[0073]

[0074]

[0075] It can be seen from the data results in Table 2 that, compared with the data in Table 1, under a shorter immersion time, the stripping liquids involved in Examples 1-11 also have significantly superior stripping effects on the polyimide film at room temperature compared to Comparative Examples 1-4, among which Example 11 has the best stripping effect without residual glue; the data comparison results of different embodiments also show that the formula of alcohol ether solvents and the formula of strong organic bases also affect the stripping efficiency of the polyimide film to a certain extent; under a shorter immersion time, the stripping liquids involved in Examples 1-11, compared to Comparative Example 5, will not cause corrosion to the metal substrate when stripping the polyimide film on the metal substrate at room temperature.

[0076] The applicant declares that the present invention illustrates the technical solution of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0077] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to 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 further describe various possible combinations.

Claims

1. A polyimide film stripping solution, characterized in that: The components of the polyimide film stripping solution include, by mass percentage, 60-80% of a strong polar solvent, 10-30% of an alcohol ether solvent, 3-10% of an organic strong base, 0.001-0.1% of a surfactant, and 0.1-1% of a metal resist.

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

3. The polyimide film stripping solution according to claim 1 or 2, characterized in that: The alcohol ether solvent includes any one 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, or a combination of at least two thereof; preferably, a combination of propylene glycol methyl ether and propylene glycol methyl ether acetate.

4. The polyimide film stripping solution according to any one of claims 1 to 3, characterized in that: The organic strong base includes any one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetramethylguanidine, tetraethylguanidine or tetrapropylguanidine, or a combination of at least two thereof; preferably, a combination of tetramethylammonium hydroxide, tetraethylammonium hydroxide and tetramethylguanidine.

5. The polyimide film stripping solution according to any one of claims 1 to 4, characterized in that: The surfactant includes any one of sodium fatty acid methyl ester ethoxylate sulfonate, monolauryl phosphate, hexadecyltrimethylammonium bromide, dodecyldimethylbenzylammonium chloride, dioctadecyldimethylammonium chloride or glyceryl monostearate, or a combination of at least two thereof.

6. The polyimide film stripping solution according to any one of claims 1 to 5, characterized in that: The metal resist comprises any one of benzotriazole, ethylenediaminetetraacetic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepenta(methylenephosphonic acid) or aminetri(methylenephosphonic acid) or a combination of at least two thereof.

7. The polyimide film stripping solution according to any one of claims 1 to 6, characterized in that: The components of the polyimide film stripping solution include, by mass percentage, 65-75% of a strong polar solvent, 16-24% of an alcohol ether solvent, 5-8% of an organic strong base, 0.01-0.05% of a surfactant, and 0.3-0.8% of a metal resist.

8. The polyimide film stripping solution according to any one of claims 1 to 7, characterized in that: The components of the polyimide film stripping solution further include, by weight percentage: 0.1-0.5% of a penetration enhancer; Preferably, the penetration enhancer comprises any one of polyethyleneimine, hexamethylenetetramine or polyethylene glycol, or a combination of at least two thereof.

9. The method for preparing a polyimide film stripping solution according to any one of claims 1 to 8, characterized in that: The preparation method comprises: A strong polar solvent, an alcohol ether solvent, an organic strong base, a surfactant, a metal anti-corrosion agent and an optional penetration promoter are stirred and mixed at 10-50° C. for 3-8 hours, and filtered to obtain the product.

10. Use of the polyimide film stripping solution according to any one of claims 1 to 8 in stripping a polyimide film from a substrate surface.

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