Low-corrosion alkaline photoresist stripping solution, preparation method and application thereof

Abstract

The application provides a low-corrosion alkaline photoresist stripping liquid and a preparation method and application thereof, the low-corrosion alkaline photoresist stripping liquid comprises the following components in proportion by weight: a metal protective agent 0.1-5 parts; an organic alkali 5-25 parts; a polar solvent 10-40 parts; ultrapure water 15-45 parts; the metal protective agent comprises water-soluble carbon dots and alkyl phosphate ester. The application further discloses a preparation method of the low-corrosion alkaline photoresist stripping liquid: first, dissolving the water-soluble carbon dots in the ultrapure water, then adding the alkyl phosphate ester and the polar solvent, stirring at room temperature until the solution is clear, adding the organic alkali and stirring uniformly to obtain the low-corrosion alkaline photoresist stripping liquid. The low-corrosion alkaline photoresist stripping liquid has almost no corrosion to copper and its alloy, and has a good application prospect and large-scale promotion potential in the field of display panel photoresist stripping.

Description

TECHNICAL FIELD

[0001] The present application relates to photoresist stripping liquid technology, in particular to a low-corrosion alkaline photoresist stripping liquid and its preparation method and application. BACKGROUND

[0002] In order to reduce the wiring line width in high generation panel, in order to save space, copper wiring which has better resistivity can be used to replace aluminum wiring. The adhesion of copper wiring to glass substrate is poor, and usually an auxiliary material selected from molybdenum or molybdenum alloy is used. After the substrate of copper wiring layer and molybdenum / molybdenum alloy layer is subjected to coating-development-etching process, the required lines are etched on the underlying metal material, and then the residual photoresist must be removed without damaging any base material, so as to proceed to the next process. At present, in order to increase the stripping capacity, the content of organic base in the stripping liquid is gradually increased, which will cause serious corrosion to the base material and metal wiring, and affect the yield of the product. Among them, copper has poor chemical resistance, and when the photoresist film is stripped in the cleaning process, copper is exposed to photoresist stripping liquid, which is easy to be oxidized or corroded, resulting in poor conductivity and large impedance.

[0003] In order to solve the problem that copper and its alloy are easily oxidized or corroded in alkaline stripping liquid, copper protective agent such as benzotriazole (BTA) is usually added in the stripping liquid. BTA not only has great toxicity, but also has the best pH value for corrosion inhibition of copper at 5-10, and its corrosion inhibition effect will decrease sharply in alkaline medium with pH>10; at the same time, there is a potential difference between copper and molybdenum, and copper will be preferentially corroded during alkaline stripping liquid treatment, resulting in pattern line width distortion. SUMMARY

[0004] The purpose of the present application is to solve the problem that copper and its alloy are easily corroded in alkaline stripping liquid, and to provide a low-corrosion alkaline photoresist stripping liquid which has almost no corrosion to copper and its alloy, and has good application prospect and large-scale promotion potential in the field of display panel photoresist stripping.

[0005] It should be noted that in the present application, unless otherwise specified, the specific meaning of "including" involved in the composition limitation and description includes both open-ended "including", "containing" and the like, and closed-ended "consisting of", "consisting essentially of" and the like.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows: a low-corrosion alkaline photoresist stripping liquid, which comprises the following components in a weight ratio:

[0007]

[0008] The metal protective agent comprises water-soluble carbon dots and alkyl phosphate.

[0009] Further, the pH of the low-corrosion alkaline photoresist stripping solution is 11.5-13.

[0010] Further, the mass ratio of the water-soluble carbon dots and the alkyl phosphate is 1-5:1.

[0011] Further, the preferred mass ratio of the water-soluble carbon dots and the alkyl phosphate is 3:1.

[0012] Further, the water-soluble carbon dots can be commercially available water-soluble carbon dots or prepared by the following method:

[0013] The carbon source and distilled water are mixed uniformly, then the N-containing compound is added and mixed again to obtain a mixed solution, the mixed solution is transferred to a high-pressure kettle with a polytetrafluoroethylene liner, heated to 150-180℃, and the reaction is continued for 5-7h, after the reaction is completed, the reaction is naturally cooled to room temperature to obtain the product, at this time, the product is dialyzed in a dialysis bag for 24-48h, and a brown carbon dot solution is obtained by dialysis, and the powder state water-soluble carbon dots are obtained by evaporation and drying.

[0014] Further, the carbon source is one or more of citric acid, amino acid, oxalic acid, and glucose.

[0015] Further, the N-containing compound is one or more of ethylenediamine, polyethyleneimine, amino acid, and urea.

[0016] Further, the amino acid is one or more of tryptophan, threonine, serine, and tyrosine.

[0017] Further, the N-containing compound is preferably ethylenediamine.

[0018] Further, the mass ratio of the N-containing compound and the carbon source is 1:1-5.

[0019] Further, the preferred mass ratio of the N-containing compound and the carbon source is 1:5.

[0020] Further, the amount of distilled water is not limited as long as it can dissolve the N-containing compound and the carbon source.

[0021] Further, the molecular weight of the dialysis bag is 1000-3000.

[0022] Further, the alkyl phosphate is one or more of tributyl phosphate, dodecyl phosphate, and octadecyl phosphate.

[0023] Further, the alkyl phosphate is preferably dodecyl phosphate.

[0024] Further, the metal protection agent is 0.1-3.6 parts.

[0025] Further, the organic base is one or more of ethanolamine, diethanolamine, N-ethylformamide, 3-methylpiperidine and aminoethylpiperazine.

[0026] Further, the organic base is preferably ethanolamine and / or diethanolamine.

[0027] Further, the organic base is 20-25 parts.

[0028] Further, the polar solvent is one or more of diethylene glycol monobutyl ether, dimethyl sulfoxide and diethylene glycol methyl ether.

[0029] Further, the polar solvent is preferably diethylene glycol monobutyl ether.

[0030] Further, the polar solvent is 15-35 parts.

[0031] Another object of the present application also discloses a preparation method of a low-corrosion alkaline photoresist stripping liquid, comprising the following steps:

[0032] First, the water-soluble carbon dots are dissolved in ultrapure water, then alkyl phosphate and polar solvent are added, and the solution is stirred at room temperature until it is clear, then the organic base is added and stirred uniformly to obtain the low-corrosion alkaline photoresist stripping liquid.

[0033] Another object of the present application also discloses the application of a low-corrosion alkaline photoresist stripping liquid in the field of stripping display panel photoresist.

[0034] Further, the low-corrosion alkaline photoresist stripping liquid is particularly suitable for stripping copper and copper alloy substrate photoresist.

[0035] Further, the steps of stripping the panel photoresist using the low-corrosion alkaline photoresist stripping liquid are as follows:

[0036] Step 1: heat the low-corrosion alkaline photoresist stripping liquid to 50-70℃, put the substrate into the low-corrosion alkaline photoresist stripping liquid and continuously oscillate, and strip the photoresist.

[0037] Step 2: rinse the substrate after stripping the photoresist with ultrapure water to remove the residual stripping liquid, and dry it with nitrogen to obtain the substrate without photoresist.

[0038] Further, the oscillation time is 0.5-2min, and the stripping time required for photoresist of different thicknesses is different, and the oscillation time is adjusted according to the thickness of the photoresist.

[0039] Further, the substrate after stripping the photoresist is rinsed with ultrapure water at least twice.

[0040] The low-corrosion alkaline photoresist stripping liquid of the present application, its preparation method and application have the following advantages compared with the prior art:

[0041] 1) The low-corrosion alkaline photoresist stripping liquid of the present application uses a combination of water-soluble carbon dots and alkyl phosphate as a metal protective agent. The carbon dots (CDs) synthesized by using acidic substances such as citric acid as a carbon source exhibit weak acidity. The carbon dots and alkyl phosphate are added first during preparation. The alkyl phosphate is partially hydrolyzed under weak acid conditions, and the hydrolysis product is the corresponding alkyl alcohol and phosphoric acid. The alkyl alcohol increases the polarity of the alkaline photoresist stripping liquid, thereby increasing the stripping rate of the photoresist. The phosphoric acid further reacts in the alkaline photoresist stripping liquid system to form a phosphate film, which can react with metal ions on the metal surface to form a dense phosphate film, thereby slowing down the corrosion of the metal and increasing the corrosion resistance of the alkaline photoresist stripping liquid.

[0042] 2) The low-corrosion alkaline photoresist stripping liquid of the present application adds a metal protective agent instead of the traditional benzotriazole corrosion inhibitor in the photoresist stripping liquid. Copper and its alloys have a positive charge on the surface after corrosion. The metal protective agent of the present application is physically adsorbed on the positively charged area of the alloy surface, and the carbon dots contain rich nitrogen and oxygen atoms, whose lone pair electrons can form a coordination bond with the empty orbit of copper to occur chemical adsorption, thereby forming a molecular adsorption layer on the copper and Mo / Cu alloy layer to inhibit the corrosion of the metal.

[0043] The low-corrosion alkaline photoresist stripping liquid of the present application has good application prospects and large-scale promotion potential in the field of display panel photoresist stripping. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 is a 25000x SEM image of a Mo / Cu substrate after the photoresist stripping liquid of Example 1 was used. Figure 1 Figure 2 is a 25000x SEM image of a Mo / Cu substrate after the photoresist stripping liquid of Example 2 was used.

[0045] Figure 2 Figure 3 is a 25000x SEM image of a Mo / Cu substrate after the photoresist stripping liquid of Example 3 was used. DETAILED DESCRIPTION

[0046] Hereinafter, the present application will be further described in conjunction with the examples and the accompanying drawings of the specification. The description of the technical features described below is based on representative embodiments, specific examples of the present application, but the present application is not limited to these embodiments, specific examples. It should be noted that:

[0047] Unless otherwise stated, the units used in this specification are international standard units, and the numerical values and numerical value ranges appearing in the present application should be understood to include the systematic errors that are unavoidable in industrial production.

[0048] ​In the present specification, a numerical range indicated using "numerical value A to numerical value B" means a range including the end point values A and B.

[0049] In the present specification, a numerical range indicated using "above" or "below" means a range including the present number.

[0050] In the present specification, the meaning indicated using "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0051] In the present specification, "optionally" or "optional" indicates that a certain substance, component, execution of a step, application of a condition, and the like is used or not used.

[0052] In the present specification, when "room temperature" is used, the temperature thereof can be 15-25°C.

[0053] In the present specification, when a manufacturer is not indicated for a reagent or an instrument, it is a general product that can be obtained by purchase on the market.

[0054] Examples 1-7

[0055] Examples 1-7 disclose various low-corrosion alkaline photoresist stripping liquids, which include the components and weight ratios as shown in Table 1, and the preparation method is as follows: first, dissolving water-soluble carbon dots in ultrapure water, then adding alkyl phosphate and polar solvent, stirring at room temperature until the solution is clear, then adding organic base and stirring uniformly to obtain the low-corrosion alkaline photoresist stripping liquid.

[0056] Table 1 Components and weight ratios of low-corrosion alkaline photoresist stripping liquids in Examples 1-7

[0057]

[0058]

[0059] The carbon dots CQD-420 used in Example 7 were purchased from Xiamen Bolite Science and Technology Co., Ltd., with a luminescence wavelength of 420±10 nm and a half-peak width ≦65 nm.

[0060] The preparation method of the water-soluble carbon dots used in the above-described Examples 1-6 is as follows: mixing carbon source and distilled water uniformly, then adding N-containing compound and mixing again, transferring the mixed solution to a polytetrafluoroethylene-lined autoclave with a volume of 30 ml, then placing the autoclave in an oven and heating to 150°C, and continuing the reaction for 5 h, after the reaction is completed, allowing the reaction to cool to room temperature naturally, which will obtain a black-brown, transparent product, at this time, the obtained product is dialyzed in a dialysis bag with a molecular weight of 1000 for 48 h, and after dialysis, a carbon dot solution is obtained, and finally, continuous evaporation drying is performed to obtain powder state carbon dots.

[0061] The amount of the N-containing compound and the carbon source is shown in Table 2; the amount of the distilled water is determined according to the solubility of the N-containing compound and the carbon source.

[0062] Table 2 Water-soluble carbon dots

[0063]

[0064] Comparative Examples 1-4

[0065] Comparative Examples 1-4 disclose various photoresist stripping liquids, which contain components and weight ratios as shown in Table 3. Comparative Example 2 and Comparative Example 4 use the same CDs1 as Example 1, and the preparation method of the water-soluble carbon dots and the preparation method of the photoresist stripping liquid are the same as those of Example 1.

[0066] Table 3 Components and weight ratios of photoresist stripping liquids in Comparative Examples 1-4

[0067]

[0068] The photoresist stripping liquids of Example 1-7 and Comparative Examples 1-4 were tested respectively, and the test results are shown in Table 4.

[0069] Table 4 Test data

[0070] Examples / Comparative Examples Substrate erosion, photoresist residue Example 1 No significant Cu erosion, no photoresist residue Example 2 No significant Cu erosion, no photoresist residue Example 3 No significant Cu erosion, no photoresist residue Example 4 No significant Cu erosion, no photoresist residue Example 5 Light Cu erosion, no photoresist residue Example 6 No significant Cu erosion, slight photoresist residue Example 7 Light Cu erosion, no photoresist residue Comparative Example 1 Significant Cu erosion, no photoresist residue Comparative Example 2 Significant Cu erosion, no photoresist residue Comparative Example 3 Significant Cu erosion, no photoresist residue Comparative Example 4 Significant Cu erosion, no photoresist residue

[0071] As can be seen from Table 4, Example 5 has a slight Cu corrosion phenomenon due to the too low content of the metal corrosion inhibitor; Example 6 has a slightly reduced stripping ability and is prone to photoresist residue due to the excessive addition of dodecyl phosphate, which reduces the alkalinity of the stripping liquid;

[0072] Comparative Example 1 does not add water-soluble carbon dots, and the hydrolysis rate of dodecyl phosphate under alkaline conditions decreases sharply, and the degree of hydrolysis usually stops at the diester stage, so the metal corrosion resistance is low, and obvious copper corrosion occurs;

[0073] Comparative Example 2 does not add alkyl phosphate, which reduces the metal corrosion resistance of the stripping liquid, and obvious copper corrosion occurs;

[0074] Comparative Example 3 uses a combination of graphene oxide and dodecyl phosphate as a metal protection agent, and since graphene oxide cannot effectively promote the hydrolysis of dodecyl phosphate, the corrosion resistance is reduced, and obvious copper corrosion occurs;

[0075] Comparative Example 4 uses CDs1 carbon dots and polyacrylamide as a combination of metal protection agents, polyacrylamide mainly prevents corrosion medium from directly contacting the metal by forming a protective film on the metal surface, the polymer is relatively stable in acidic medium, and the corrosion inhibition effect is good, but in alkaline environment, its corrosion resistance is weak, and obvious copper corrosion phenomenon occurs.

[0076] From Figure 1 It can be seen that the copper metal layer produces obvious corrosion, and after the copper is corroded, the Mo of the bottom layer is displayed; from Figure 2 It can be seen that the copper metal layer does not produce corrosion phenomenon; by Figure 1 and Figure 2 It can be seen that the low-corrosion alkaline photoresist stripping liquid provided by the present application has good copper corrosion inhibition ability.

[0077] Among them:

[0078] The performance test method is:

[0079] The same thickness of the substrate is used for testing. The stripping liquid temperature is raised to 60℃, and after the temperature is stable, the substrate is put into the stripping liquid for stripping, and the stripping time is the same, which is 2min. After the substrate is taken out, washed and dried, the substrate is cracked, sampled and detected by SEM, and the test results are shown in Figures 1-2 and Table 4.

[0080] Finally, it should be pointed out that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present 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 present application.

Claims

1. A low-corrosion alkaline photoresist stripping solution, characterized in that, The components include the following weight proportions: Metal protectant 0.1-5 parts; 5-25 parts of organic base; 10-40 parts of polar solvent; 15-45 parts ultrapure water; The metal protectant includes water-soluble carbon dots and alkyl phosphates; The water-soluble carbon dots are prepared using one or more of citric acid, amino acids, oxalic acid, and glucose as carbon sources.

2. The low-corrosion alkaline photoresist stripping solution according to claim 1, characterized in that, The mass ratio of the water-soluble carbon dots to the alkyl phosphate ester is 1-5:

1.

3. The low-corrosion alkaline photoresist stripping solution according to claim 1 or 2, characterized in that, The water-soluble carbon dots are prepared by the following method: a carbon source and distilled water are mixed evenly, then a nitrogen-containing compound is added and mixed evenly again to obtain a mixture. The mixture is transferred to a high-pressure reactor with a polytetrafluoroethylene liner, heated to 150-180°C, and reacted for 5-7 hours. After the reaction is completed, the reactants are naturally cooled to room temperature to obtain the product. The product is dialyzed through a dialysis bag for 24-48 hours and evaporated to obtain water-soluble carbon dots.

4. The low-corrosion alkaline photoresist stripping solution according to claim 3, characterized in that, The mass ratio of the nitrogen-containing compound to the carbon source is 1:1-5; And / or, the N-containing compound is one or more of ethylenediamine, polyethyleneimine, amino acids, and urea; And / or, the molecular weight of the dialysis bag is 1000-3000.

5. The low-corrosion alkaline photoresist stripping solution according to claim 1, characterized in that, The alkyl phosphate is one or more of tributyl phosphate, dodecyl phosphate, and octadecyl phosphate.

6. The low-corrosion alkaline photoresist stripping solution according to claim 1, characterized in that, The organic base is one or more of ethanolamine, diethanolamine, N-ethylformamide, 3-methylpiperidine, and aminoethylpiperazine.

7. The low-corrosion alkaline photoresist stripping solution according to claim 1, characterized in that, The polar solvent is one or more of diethylene glycol monobutyl ether, dimethyl sulfoxide, and diethylene glycol methyl ether.

8. A method for preparing the low-corrosion alkaline photoresist stripping solution according to any one of claims 1-7, characterized in that, Includes the following steps: First, water-soluble carbon dots are dissolved in ultrapure water. Then, alkyl phosphate and polar solvent are added. The mixture is stirred at room temperature until the solution is clear. Finally, an organic base is added and stirred until homogeneous to obtain the low-corrosion alkaline photoresist stripping solution.

9. The application of the low-corrosion alkaline photoresist stripping solution according to any one of claims 1-7 in the field of stripping photoresist from display panels.

10. The application according to claim 9, characterized in that, The steps for removing the photoresist from the display panel using a low-corrosion alkaline photoresist stripping solution are as follows: Step 1: Heat the low-corrosion alkaline photoresist stripping solution to 50-70℃, immerse the substrate in the low-corrosion alkaline photoresist stripping solution and continuously agitate to peel off the photoresist. Step 2: Rinse the substrate after photoresist stripping with ultrapure water to remove residual stripping solution, and dry it with nitrogen to obtain a substrate with photoresist removed.

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