Low-corrosion alkaline photoresist stripping liquid as well as preparation method and application thereof

Abstract

The invention provides low-corrosion alkaline photoresist stripping liquid as well as a preparation method and application thereof. The low-corrosion alkaline photoresist stripping liquid comprises the following components in parts by weight: 0.1-5 parts of a metal protective agent; 5-25 parts of an organic base; 10-40 parts of a polar solvent; 15 to 45 parts of ultrapure water; the metal protective agent comprises water-soluble carbon dots and alkyl phosphate. The invention also discloses a preparation method of the low-corrosion alkaline photoresist stripping liquid, which comprises the following steps: dissolving the water-soluble carbon dots in ultrapure water, then adding the alkyl phosphate and the polar solvent, stirring at room temperature until the solution is clear, adding the organic alkali, and uniformly stirring to obtain the low-corrosion alkaline photoresist stripping liquid. The low-corrosion alkaline photoresist stripper almost has no corrosion to copper and alloys thereof, and has good application prospects and large-scale popularization potential in the field of photoresist stripping of display panels.

Description

Technical Field

[0001] The present invention relates to the technology of photoresist stripper, and particularly to a low-corrosion alkaline photoresist stripper and its preparation method and application. Background Art

[0002] In order to reduce the wiring line width in high-generation panels to save space, copper wiring with better resistivity can be used to replace aluminum wiring. The adhesion between copper wiring and the glass substrate is poor, and usually a material selected from molybdenum and molybdenum alloy is used as an auxiliary in the lower layer. After the copper wiring layer and the substrate of the molybdenum / molybdenum alloy layer go through the processes of coating - developing - etching, after etching the required lines on the bottom metal material, it is necessary to ensure that no substrate is damaged while removing the residual photoresist before proceeding to the next process. Currently, in order to increase the stripping ability, the content of organic base in the stripper is gradually increasing, which will cause relatively serious corrosion to the substrate and metal wiring, affecting the product yield. Among them, copper has poor chemical resistance. When stripping the photoresist film in the cleaning process, copper is exposed to the photoresist stripper and is easily oxidized or corroded, resulting in poor conductivity and increased impedance.

[0003] In order to solve the problem that copper and its alloys are easily oxidized or corroded in alkaline strippers, currently, copper protectants such as benzotriazoles (BTA) are usually added to the stripper. BTA not only has high toxicity, but also its optimal pH value for inhibiting copper corrosion is 5 - 10. In an alkaline medium with pH > 10, its corrosion inhibition effect will drop sharply; at the same time, there is a potential difference between copper and molybdenum. When treated with an alkaline stripper, copper will be preferentially corroded, resulting in distortion of the pattern line width. Summary of the Invention

[0004] The purpose of the present invention is to propose a low-corrosion alkaline photoresist stripper for the problem that current alkaline strippers are prone to corrode copper and its alloys. This photoresist stripper has almost no corrosion to copper and its alloys and has good application prospects and large-scale popularization potential in the field of photoresist stripping in display panels.

[0005] It should be noted that in the present invention, unless otherwise specified, the specific meaning of "including" related to composition limitation and description includes both the open "including", "containing" and their similar meanings, and also the closed "consisting of", "composed of" and their similar meanings.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is: a low-corrosion alkaline photoresist stripper, comprising the following components in weight ratio:

[0007]

[0008] The metal protectant includes water-soluble carbon dots and alkyl phosphate esters.

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

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

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

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

[0013] Mix the carbon source and distilled water evenly, then add the N-containing compound and mix evenly again to obtain a mixed solution. Transfer the mixed solution to an autoclave with a polytetrafluoroethylene liner, heat it to 150 - 180 °C, and continuously react for 5 - 7 h. After the reaction is completed, naturally cool the reactant to room temperature to obtain a product. At this time, dialyze the product with a dialysis bag for 24 - 48 h to obtain a brown carbon dot solution, and evaporate and dry it to obtain water-soluble carbon dots in powder form.

[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 to the carbon source is 1:1 - 5.

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

[0020] Further, the amount of distilled water used is determined by the ability to dissolve the N-containing compound and the carbon source, and there is no limitation.

[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 protectant 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 amount of 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 amount of the polar solvent is 15-35 parts.

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

[0032] First, dissolve the water-soluble carbon dots in ultrapure water, then add alkyl phosphate and a polar solvent, stir at room temperature until the solution is clear, and then add an organic base and stir evenly to obtain the low-corrosion alkaline photoresist stripper.

[0033] Another object of the present invention also discloses an application of the low-corrosion alkaline photoresist stripper in the field of stripping photoresist of display panels.

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

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

[0036] Step 1: Heat the low-corrosion alkaline photoresist stripper to 50-70 °C, place the substrate in the low-corrosion alkaline photoresist stripper and continuously oscillate to strip the photoresist;

[0037] Step 2: Rinse the substrate after stripping the photoresist with ultrapure water to remove the residual stripper, and dry it with nitrogen to obtain the substrate with the photoresist removed.

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

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

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

[0041] 1) The low-corrosion alkaline photoresist stripper of the present invention uses a combination of water-soluble carbon dots and alkyl phosphate esters as metal protectants. The carbon dots (CDs) synthesized using acidic substances such as citric acid as carbon sources show weak acidity. During preparation, carbon dots and alkyl phosphate esters are added first. The alkyl phosphate esters are partially hydrolyzed under weak acid conditions, and the hydrolysis products are the corresponding alkyl alcohols and phosphoric acid. The alkyl alcohols increase the polarity of the alkaline photoresist stripper, thereby enhancing the stripping rate of the photoresist. The phosphoric acid further reacts in the alkaline photoresist stripper system to form phosphates, which can react with metal ions on the metal surface to form a dense phosphate film, thereby slowing down metal corrosion and increasing the corrosion resistance of the alkaline photoresist stripper.

[0042] 2) The low-corrosion alkaline photoresist stripper of the present invention adds a metal protectant to replace the benzotriazole-based corrosion inhibitor in the traditional photoresist stripper. After corrosion, the surface of copper and its alloys is positively charged. On the one hand, the metal protectant of the present invention is adsorbed on the positively charged region of the alloy surface in the form of physical adsorption. On the other hand, the carbon dots contain abundant nitrogen and oxygen atoms, and their lone pair electrons can form coordination bonds with the empty orbitals of copper to undergo chemical adsorption, thereby forming a molecular adsorption layer on the copper and Mo / Cu alloy layers to inhibit metal corrosion.

[0043] The low-corrosion alkaline photoresist stripper of the present invention has good application prospects and great potential for large-scale promotion in the field of photoresist stripping for display panels. Description of the Drawings

[0044] Attached Figure 1 is a 25,000-fold magnified SEM image of the Mo / Cu substrate after using the photoresist stripper of Comparative Example 2.

[0045] Attached Figure 2 is a 25,000-fold magnified SEM image of the Mo / Cu substrate after using the photoresist stripper of Example 1. Detailed Embodiments

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

[0047] Unless otherwise specified, the units used in this specification are all international standard units, and the numerical values and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0048] In this specification, the numerical range expressed as "numerical value A to numerical value B" means a range including the endpoint numerical values A and B.

[0049] In this specification, the numerical range expressed as "above" or "below" means a numerical range including this number.

[0050] In this specification, the meaning expressed by "may" includes both the meaning of performing a certain treatment and not performing a certain treatment.

[0051] In this specification, "optional" or "optionally" means that certain substances, components, execution steps, applied conditions and other factors are used or not used.

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

[0053] In this specification, for the reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0054] Examples 1 - 7

[0055] Examples 1 - 7 disclose a variety of low - corrosion alkaline photoresist strippers. The components and weight ratios thereof are shown in Table 1, and the involved preparation method is as follows: First, dissolve water - soluble carbon dots in ultrapure water, then add alkyl phosphate and polar solvent, stir at room temperature until the solution is clear, and then add organic base and stir evenly to obtain the low - corrosion alkaline photoresist stripper.

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

[0057]

[0058]

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

[0060] The preparation method of the water - soluble carbon dots used in the photoresist strippers of the above Examples 1 - 6 is as follows: Mix the carbon source and distilled water evenly, then add the N - containing compound and mix evenly again. Transfer the mixed solution to a high - pressure autoclave with a polytetrafluoroethylene liner. The volume of the high - pressure autoclave is 30 ml. Then place the high - pressure autoclave in an oven and heat it to 150 °C, and continuously react for 5 h. After the reaction is completed, let the reactants cool naturally to room temperature, and a black - brown and transparent product will be obtained. At this time, dialyze the obtained product with a dialysis bag with a molecular weight of 1000 for 48 h to obtain a carbon dot solution, and finally continuously evaporate and dry to obtain carbon dots in powder form.

[0061] The dosages of the N-containing compound and the carbon source are shown in Table 2; the dosage of the distilled water is such that it can dissolve 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 a variety of photoresist stripping liquids, and the components and weight ratios thereof are shown in Table 3. The CDs1 used in Comparative Examples 2 and 4 are the same as those in Example 1, and the preparation methods of the water-soluble carbon dots and the photoresist stripping liquid are the same as those in Example 1.

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

[0067]

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

[0069] Table 4 Test data

[0070] Examples / Comparative Examples Substrate corrosion and photoresist residue Example 1 No obvious Cu corrosion and no photoresist residue Example 2 No obvious Cu corrosion and no photoresist residue Example 3 No obvious Cu corrosion and no photoresist residue Example 4 No obvious Cu corrosion and no photoresist residue Example 5 Slight Cu corrosion and no photoresist residue Example 6 No obvious Cu corrosion and slight photoresist residue Example 7 Slight Cu corrosion and no photoresist residue Comparative Example 1 Obvious Cu corrosion and no photoresist residue Comparative Example 2 Obvious Cu corrosion and no photoresist residue Comparative Example 3 Obvious Cu corrosion and no photoresist residue Comparative Example 4 Obvious Cu corrosion and no photoresist residue

[0071] As can be seen from Table 4, in Example 5, due to the too low content of the metal corrosion inhibitor, a slight Cu corrosion phenomenon occurred; in Example 6, the addition of excessive dodecyl phosphate reduced the alkalinity of the stripping liquid, and its stripping ability was slightly reduced, and photoresist residues were easily generated;

[0072] In Comparative Example 1, water-soluble carbon dots were not added, and the hydrolysis rate of dodecyl phosphate decreased sharply under alkaline conditions, and the hydrolysis degree usually stopped at the diester stage, and its metal anti-corrosion performance was low, and an obvious copper corrosion phenomenon occurred;

[0073] In Comparative Example 2, alkyl phosphate was not added, resulting in a reduction in the metal corrosion resistance of the stripping liquid, and an obvious copper corrosion phenomenon occurred;

[0074] In Comparative Example 3, a combination of graphene oxide and dodecyl phosphate was used as a metal protection agent. Since graphene oxide could not effectively promote the hydrolysis of dodecyl phosphate, its corrosion resistance decreased, and an obvious copper corrosion phenomenon occurred;

[0075] Comparative Example 4 used a combination of CDs1 carbon dots and polyacrylamide as a metal protectant. Polyacrylamide mainly forms a protective film on the metal surface to prevent the corrosive medium from directly contacting the metal. This polymer is relatively stable in acidic media and has a good effect on inhibiting corrosion. However, its corrosion resistance is weak in an alkaline environment, and obvious copper corrosion occurs.

[0076] From Figure 1 it can be seen that obvious corrosion occurred on the copper metal layer. After the copper was corroded, the underlying Mo was revealed; from Figure 2 it can be seen that no corrosion occurred on the copper metal layer; by Figure 1 and Figure 2 comparison, it can be seen that the low-corrosion alkaline photoresist stripper provided by the present invention has good ability to inhibit copper corrosion.

[0077] Wherein:

[0078] The test method for performance is as follows:

[0079] Substrates with the same thickness specification were used for testing. The temperature of the stripper was raised to 60 °C. After the temperature stabilized, the substrates were respectively placed in the stripper for stripping, and the stripping time was the same, both being 2 min. After the substrates were taken out, washed, dried, cracked, and prepared for SEM detection, the test results are shown in Figures 1 - 2 and Table 4.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some 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 invention.

Claims

1. A low-corrosive alkaline photoresist stripping solution, characterized in that: The composition includes the following components in weight ratio: The metal protective agent includes water-soluble carbon dots and alkyl phosphate.

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 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, and then a N-containing compound is added and mixed evenly again to obtain a mixed solution, the mixed solution is transferred to an autoclave with a polytetrafluoroethylene liner, heated to 150-180° C., and the reaction is continued for 5-7 hours. After the reaction is completed, the reactant is naturally cooled to room temperature to obtain a product; the product is dialyzed with a dialysis bag for 24-48 hours, and evaporated and dried to obtain water-soluble carbon dots.

4. The low-corrosion alkaline photoresist stripping solution according to claim 3, characterized in that: The carbon source is one or more of citric acid, amino acids, oxalic acid and glucose; And / or, the mass ratio of the N-containing compound to the carbon source is 1:1-5; and / or, the N-containing compound is one or more of ethylenediamine, polyethyleneimine, amino acid 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 to 7, characterized in that: The following steps are involved: Firstly, water-soluble carbon dots are dissolved in ultrapure water, then alkyl phosphate and polar solvent are added, stirred at room temperature until the solution is clear, and then organic base is added and stirred evenly to obtain the low-corrosion alkaline photoresist stripping solution.

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

10. The use according to claim 9, characterized in that: The steps of stripping the display panel photoresist using a low-corrosive alkaline photoresist stripping solution are as follows: Step 1: Heat the low-corrosive alkaline photoresist stripping solution to 50-70° C., place the substrate in the low-corrosive alkaline photoresist stripping solution and continuously shake to strip the photoresist; Step 2: Rinse the substrate after the photoresist is stripped with ultrapure water to remove the stripping liquid residue, and blow dry with nitrogen to obtain a substrate with the photoresist removed.

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