A negative photoresist stripping solution and a preparation method thereof

Abstract

This application relates to the field of electronic chemicals, and more specifically to a negative photoresist stripping solution and its preparation method. The negative photoresist stripping solution, by mass percentage, comprises: 4-7% main alkali agent, 10-20% organic amine, 35-50% organic medium, 2-6% combined functional agent, 0.3-0.6% wetting and penetrating agent, 0.2-0.4% defoamer, 0.2-0.3% dispersing and suspending agent, with deionized water to make up the balance. The negative photoresist stripping solution prepared in this application not only precisely balances stripping and dissolving properties and provides excellent metal protection, but also effectively reduces the copper corrosion rate. Furthermore, it significantly reduces the amount of stripping solution used during application, overcoming the cost problem of needing to add new solution due to the evaporation of traditional formulations. This application uses water to replace part of the new solution, and new solution can be added by adjusting the liquid level, greatly reducing the amount of stripping solution used.

Description

Technical Field

[0001] This application relates to the field of electronic chemicals, and more specifically to a negative photoresist stripping solution and its preparation method. Background Technology

[0002] In the manufacturing field of thin-film transistor liquid crystal displays (TFT-LCDs), with the advancement of panel generation lines and the refinement of display technology, COA (Color Filter on Array) technology has become the mainstream high-end process solution. This technology directly fabricates the color filter on the array substrate, effectively improving the aperture ratio and display accuracy. However, in this highly integrated process, defects inevitably occur in the upper alignment film and color filter during coating and curing. To ensure the yield of the final product, it is necessary to selectively remove and repair the defective film layers using specific rework solutions. Negative photoresist stripping solution is the key chemical material that undertakes this rework repair function.

[0003] Existing negative photoresist stripping solutions typically use tetramethylammonium hydroxide as the main alkali, supplemented with organic amines, organic solvents, and small amounts of additives. These traditional formulations face a series of severe challenges when applied to the precision rework of high-generation panels. First, the synergistic control between stripping efficiency and dissolution rate is a critical challenge. An ideal rework solution needs to completely peel the defective film layer from the substrate within a short time and rapidly dissolve the peeled solid fragments in the stripping solution system. If the stripping speed is too fast and the dissolution rate is too slow, a large amount of undissolved strip-shaped or block-shaped residue will accumulate in the circulating filtration system, easily causing filter clogging, increasing maintenance costs, and potentially leading to poor stripping solution circulation and secondary pollution. Conversely, if the stripping speed itself is too slow, it will directly drag down the production efficiency of the entire rework process, resulting in lost production capacity.

[0004] Secondly, the rework process is crucial for protecting the various functional films on the substrate. In particular, the copper metal traces and indium tin oxide transparent electrodes on the substrate are highly susceptible to chemical corrosion in the strongly alkaline stripping solution environment, leading to trace damage, increased resistance, and even rendering the entire expensive array substrate unusable. Therefore, although existing technologies commonly add corrosion inhibitors, their corrosion inhibition efficiency is often insufficient to meet the near-stringent requirements of high-generation lines for trace integrity. Summary of the Invention

[0005] In summary, from the perspectives of production operation and economics, traditional stripping fluids suffer from high volatility and poor stability in continuous operation. The volatile components, such as organic amines and solvents, are continuously lost during production, leading to a decrease in the concentration of effective ingredients and the level of the fluid, necessitating frequent replenishment. This directly increases material costs and causes the composition within the stripping fluid tank to fluctuate, threatening process stability and product yield consistency. Therefore, developing a negative photoresist stripping fluid that can precisely balance stripping and dissolving performance and provide excellent metal protection has become an urgent technical problem to be solved in this field. Through in-depth research in this technical field, the applicant has ultimately proposed a negative photoresist stripping fluid and its preparation method in this application to solve these technical problems.

[0006] A negative photoresist stripping solution, by mass percentage, comprises: 4-7% main alkali agent, 10-20% organic amine, 35-50% organic medium, 2-6% combined functional agent, 0.3-0.6% wetting and penetrating agent, 0.2-0.4% defoamer, 0.2-0.3% dispersing and suspending agent, and deionized water to make up the balance.

[0007] Preferably, the mass ratio of the main alkali agent, organic amine and combined functional agent is (4~6):(12~16):(3.5~5).

[0008] Preferably, the mass ratio of the main alkali agent, organic amine and combined functional agent is (4.5~5.5):(13~15):(3.5~4).

[0009] Preferably, the primary alkali is an aqueous solution of tetramethylammonium hydroxide.

[0010] Preferably, the mass concentration of the tetramethylammonium hydroxide aqueous solution is 20-30%.

[0011] Preferably, the mass concentration of the tetramethylammonium hydroxide aqueous solution is 24-28%.

[0012] Preferably, the organic amine is at least one of diethylenetriamine, hydroxyethyl ethylenediamine, and aminoethyl ethanolamine.

[0013] Preferably, the organic amine is diethylenetriamine or hydroxyethylethylenediamine.

[0014] Preferably, the organic amine is diethylenetriamine.

[0015] Preferably, the organic medium is at least one of diethylene glycol butyl ether, dipropylene glycol methyl ether, N-methylpyrrolidone, and propylene glycol methyl ether acetate.

[0016] Preferably, the organic medium is diethylene glycol butyl ether or dipropylene glycol methyl ether.

[0017] Preferably, the organic medium is diethylene glycol butyl ether.

[0018] Preferably, the combined functional agent is a combination of sodium dodecyl diphenyl ether disulfonate, potassium perfluorobutyl sulfonate, and polyvinyl imidazole copolymer.

[0019] Preferably, the mass ratio of sodium dodecyl diphenyl ether disulfonate, potassium perfluorobutyl sulfonate, and polyvinyl imidazole copolymer is (1~1.5):(0.5~0.8):(0.6~1).

[0020] Preferably, the mass ratio of sodium dodecyl diphenyl ether disulfonate, potassium perfluorobutyl sulfonate, and polyvinyl imidazole copolymer is (1.1~1.2):(0.6~0.7):(0.8~1).

[0021] Preferably, the polyvinyl imidazole copolymer is VPI-55K, sourced from BASF, Germany.

[0022] The combined functional agents incorporated in this application effectively address the systemic problems of existing stripping solutions. Sodium dodecyl diphenyl ether disulfonate and potassium perfluorobutyl sulfonate work together to enhance the penetration and stripping efficiency of the stripping solution. The former ensures that the stripping solution fully wets the substrate surface, while the latter, with its excellent spreading ability, promotes rapid penetration of the stripping solution to the bottom of the film layer to be removed, creating conditions for efficient stripping. While achieving rapid stripping, the composition also considers subsequent processing and equipment protection. Sodium dodecyl diphenyl ether disulfonate effectively disperses the solid residue generated during stripping; the polyvinyl imidazole copolymer, by adsorbing onto the particle surface, prevents its aggregation and deposition, thereby avoiding filter clogging and ensuring production continuity.

[0023] On the other hand, this composition also provides reliable metal protection, forming a protective layer on the surface of metals such as copper. It works synergistically with other components to construct a corrosion-inhibiting barrier, ensuring the safety of the substrate circuitry while achieving efficient stripping, thereby significantly limiting the copper corrosion rate. This complementary functionality achieves a synergistic improvement in stripping efficiency, anti-clogging capability, and metal protection performance.

[0024] Preferably, the wetting and penetrating agent is at least one selected from nonylphenol polyoxyethylene ether, sorbitan monooleate, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and sodium lauryl sulfate.

[0025] Preferably, the wetting and penetrating agent is nonylphenol polyoxyethylene ether or sorbitol monooleate.

[0026] Preferably, the wetting and penetrating agent is nonylphenol polyoxyethylene ether.

[0027] Preferably, the defoamer is at least one of acetylenic diols, fluorocarbons, and organosilicones.

[0028] Preferably, the defoamer is an acetylenic diol or an organosilicon.

[0029] Preferably, the defoamer is an acetylenic diol.

[0030] Preferably, the dispersing suspending agent is at least one of sodium polyacrylate, hydroxyethyl cellulose, polyurethane, fumed silica, and bentonite.

[0031] Preferably, the dispersing suspending agent is sodium polyacrylate or hydroxyethyl cellulose.

[0032] Preferably, the dispersing suspending agent is sodium polyacrylate.

[0033] Preferably, the mass ratio of the combined functional agent, wetting and penetrating agent and dispersing and suspending agent is (3.5~5):(0.4~0.5):(0.2~0.25).

[0034] A method for preparing a negative photoresist stripping solution includes the following steps: S1: In a mixing vessel, a combination of functional agents and 10-20 wt% deionized water are mixed, heated to 50-60℃ and stirred until completely homogeneous to obtain a pre-prepared solution; S2: The remaining deionized water is added to a reaction vessel, stirred at 120-150 rpm, and the main alkali agent is added, followed by the organic amine. At this time, the temperature of the reaction vessel is controlled at 35-40℃. After the addition is completed, the stirring speed is increased to 250-350 rpm and stirred continuously for 15-30 minutes to obtain the main solution; S3: The pre-prepared solution is added to the main solution, the stirring speed is adjusted to 150-200 rpm, and the remaining raw materials are added slowly in sequence. After the addition is completed, the stirring speed is increased to 350-450 rpm and stirred continuously for 20-30 minutes to ensure that all components are completely dissolved and mixed evenly to form a uniform and transparent solution. Then, the temperature of the solution is lowered to 20-25℃, and it is matured under these mild stirring conditions for 2-4 hours. The solution is then obtained.

[0035] The beneficial effects of this application are:

[0036] 1. The negative photoresist stripping solution prepared in this application can not only accurately balance the stripping and dissolving performance and provide excellent metal protection, but also effectively reduce the copper corrosion rate. In addition, it significantly reduces the amount of stripping solution used during use, which makes up for the cost problem of needing to add new solution due to the evaporation of stripping solution in traditional formulations. Furthermore, this application uses water to replace part of the new solution, and new solution can be added through the liquid level, which greatly reduces the amount of stripping solution used.

[0037] 2. By optimizing the formulation and strategically using water as the main replenishing agent to maintain the system level, this stripping fluid effectively reduces the loss and replenishment frequency of high-cost organic components due to volatilization during long-term cyclic use. This not only directly reduces material costs but also simplifies the operation process in production and maintenance, and improves the overall application effect and quality.

[0038] 3. The combined functional agents added in this application can effectively solve the systemic problems of existing stripping solutions. They can work together to significantly improve the spreading ability of the stripping solution, promote the rapid penetration of the stripping solution to the bottom of the membrane layer to be removed, and while completing rapid stripping, the composition also takes into account subsequent processing and equipment protection. It can effectively disperse the solid residue generated by stripping and prevent its aggregation and deposition by adsorbing on the particle surface, thereby avoiding the problem of filter clogging and ensuring the continuity of production. Detailed Implementation

[0039] Example 1

[0040] A negative photoresist stripping solution, by mass percentage, comprises: 5% main alkali agent, 15% organic amine, 38.5% organic medium, 3.8% combined functional agent, 0.4% wetting and penetrating agent, 0.3% defoamer, 0.3% dispersing and suspending agent, and deionized water to make up the balance.

[0041] The main alkali agent is an aqueous solution of tetramethylammonium hydroxide with a mass concentration of 25%.

[0042] The organic amine is diethylenetriamine; the organic medium is diethylene glycol butyl ether.

[0043] The combined functional agents are sodium dodecyl diphenyl ether disulfonate, potassium perfluorobutyl sulfonate, and polyvinyl imidazole copolymer in a mass ratio of 1.2:0.6:1. The polyvinyl imidazole copolymer is VPI-55K, sourced from BASF, Germany.

[0044] The wetting and penetrating agent is nonylphenol polyoxyethylene ether; the defoamer is acetylenol® 104; and the dispersing and suspending agent is sodium polyacrylate.

[0045] A method for preparing a negative photoresist stripping solution includes the following steps: S1: Mix the combined functional agent and 15wt% deionized water in a mixing vessel, heat to 60℃ and stir until completely homogeneous to obtain a pre-prepared solution; S2: Add the remaining deionized water to the reaction vessel, stir at 140rpm, add the main alkali agent, and then add the organic amine. At this time, control the temperature of the reaction vessel at 40℃. After the addition is completed, increase the stirring speed to 300rpm and continue stirring for 20min to obtain the main solution; S3: Add the pre-prepared solution to the main solution, adjust the stirring speed to 180rpm, and slowly add the remaining raw materials in sequence. After the addition is completed, increase the stirring speed to 380rpm and continue stirring for 25min to ensure that all components are completely dissolved and mixed evenly to form a uniform and transparent solution. Then, lower the temperature of the solution to 24℃ and mature it under these mild stirring conditions for 3h. The solution is then obtained.

[0046] Example 2

[0047] This embodiment differs from Embodiment 1 only in the following way: a negative photoresist stripping solution, by mass percentage, comprises: 6% main alkali agent, 13.5% organic amine, 38.5% organic medium, 4.2% combined functional agent, 0.4% wetting and penetrating agent, 0.3% defoamer, 0.3% dispersing and suspending agent, and deionized water to make up the balance.

[0048] The remaining implementation methods are the same.

[0049] Example 3

[0050] This embodiment differs from Embodiment 1 only in the following way: a negative photoresist stripping solution, by mass percentage, comprises: 4.5% main alkali agent, 16% organic amine, 38.5% organic medium, 3.5% combined functional agent, 0.4% wetting and penetrating agent, 0.3% defoamer, 0.3% dispersing and suspending agent, and deionized water to make up the balance.

[0051] The remaining implementation methods are the same.

[0052] Comparative Example 1

[0053] This comparative example differs from Example 1 only in the following way: a negative photoresist stripping solution, by mass percentage, comprises: 7.5% main alkali agent, 15% organic amine, 38.5% organic medium, 1.2% combined functional agent, 0.4% wetting and penetrating agent, 0.3% defoamer, 0.3% dispersing and suspending agent, and deionized water to make up the balance.

[0054] The remaining implementation methods are the same.

[0055] Comparative Example 2

[0056] This comparative example differs from Example 1 only in the following way: a negative photoresist stripping solution, by mass percentage, comprises: 6.5% main alkali agent, 8.5% organic amine, 38.5% organic medium, 5.8% combined functional agent, 0.4% wetting and penetrating agent, 0.3% defoamer, 0.3% dispersing and suspending agent, and deionized water to make up the balance.

[0057] The remaining implementation methods are the same.

[0058] Comparative Example 3

[0059] The only difference between this comparative example and Example 1 is that the combined functional agent is a combination of sodium dodecyl diphenyl ether disulfonate, potassium perfluorobutyl sulfonate, and polyvinyl imidazole copolymer in a mass ratio of 0.5:1.2:1.

[0060] The remaining implementation methods are the same.

[0061] Comparative Example 4

[0062] The only difference between this comparative example and Example 1 is that the combined functional agent is a combination of sodium dodecyl diphenyl ether disulfonate, potassium perfluorobutyl sulfonate, and polyvinyl imidazole copolymer in a mass ratio of 2:0.2:1.

[0063] The remaining implementation methods are the same.

[0064] Comparative Example 5

[0065] The only difference between this comparative example and Example 1 is that the combined functional agent is a combination of sodium dodecyl diphenyl ether disulfonate and potassium perfluorobutyl sulfonate in a mass ratio of 1.2:0.6.

[0066] The remaining implementation methods are the same.

[0067] Comparative Example 6

[0068] This comparative example differs from Example 1 only in the following way: the organic amine is triethanolamine.

[0069] The remaining implementation methods are the same.

[0070] Performance testing

[0071] 1. Peeling efficiency: The test reference is IPC-TM-650 2.4.38 (2020). The peeling time (s) is recorded, and the average of 10 test results is recorded in Table 1.

[0072] 2. Solubility test: The stripping solution was placed in a beaker and kept at a constant temperature of 70°C in a water bath. The COA RGB substrate samples were then placed in the beaker and soaked for 60 minutes. The dissolution status of the stripping solution was observed. After that, the solution was filtered through a 300μm filter cloth and the dissolution status was observed. The results were recorded in Table 1.

[0073] 3. Corrosion test: The stripping solution was placed in a constant temperature water bath, and then the RGB substrate sample was placed in a 70℃ constant temperature water bath for 120 minutes. After immersion, it was rinsed with water and air-dried to confirm the corrosion status, namely PV layer corrosion and Cu corrosion. Corrosion area ≤1% was considered no obvious corrosion, corrosion area >1% and ≤10% was considered slight corrosion, and corrosion area >10% was considered obvious corrosion. The results were recorded in Table 1.

[0074] 4. Lifetime test: Add 300mL of stripping solution at 70℃ to a constant temperature water bath. Place a 5cm*5cm sample in the 70℃ constant temperature water bath and soak for a fixed time. Rinse with water, air dry, confirm the stripping status and record the stripping time. After confirming the stripping status, continue to add one sample until color resistance residue appears within 10 minutes. Record the number of color resistance residues. Record the results in Table 1.

[0075] 5. Volatility test: 300mL of stripping solution at 70℃ was placed in a 500ml open beaker and kept at a constant temperature of 70℃ in a water bath. The test process was set for 6 hours. The sample mass was weighed every 1 hour, and the evaporation rate after 6 hours was recorded. The average of 10 tests was recorded in Table 1.

[0076] Table 1 Performance Test Results

[0077]

[0078] The final performance test results demonstrate that Examples 1-3 of this application achieved superior performance compared to Comparative Examples 1-6. This is mainly due to the corresponding technical solutions defined in this application used in Examples 1-3, especially the combined functional agents added in this application, which effectively solve the systemic problems of existing stripping solutions. They work together to significantly improve the spreading ability of the stripping solution, promote the rapid penetration of the stripping solution to the bottom of the membrane layer to be removed, and while completing rapid stripping, the composition also takes into account subsequent processing and equipment protection. It can effectively disperse the solid residue generated by stripping and prevent its aggregation and deposition by adsorbing on the particle surface, thereby avoiding the problem of filter clogging, ensuring the continuity of production, and thus obtaining superior performance results compared to the comparative examples.

Claims

1. A negative photoresist stripping solution, characterized by: By mass percentage, the raw materials include: 4-7% main alkali agent, 10-20% organic amine, 35-50% organic medium, 2-6% combined functional agent, 0.3-0.6% wetting and penetrating agent, 0.2-0.4% defoamer, 0.2-0.3% dispersing and suspending agent, and deionized water to make up the balance; The combined functional agent is a combination of sodium dodecyl diphenyl ether disulfonate, potassium perfluorobutyl sulfonate, and polyvinyl imidazole copolymer, with a mass ratio of (1.1~1.2):(0.6~0.7):(0.8~1). The organic amine is diethylenetriamine; The mass ratio of the main alkali agent, organic amine, and combined functional agent is (4~6):(12~16):(3.5~5). The main alkali agent is an aqueous solution of tetramethylammonium hydroxide with a mass concentration of 20-30%.

2. The negative photoresist stripping solution according to claim 1, characterized in that: The organic medium is at least one of diethylene glycol butyl ether, dipropylene glycol methyl ether, N-methylpyrrolidone, and propylene glycol methyl ether acetate.

3. The negative photoresist stripping solution according to claim 2, characterized in that: The polyvinyl imidazole copolymer is VPI-55K.

4. The negative photoresist stripping solution according to claim 3, characterized in that: The wetting and penetrating agent is at least one of nonylphenol polyoxyethylene ether, sorbitol monooleate, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and sodium lauryl sulfate.

5. The negative photoresist stripping solution according to claim 4, characterized in that: The dispersing and suspending agent is at least one of sodium polyacrylate, hydroxyethyl cellulose, polyurethane, fumed silica, and bentonite.

6. The method for preparing the negative photoresist stripping solution according to claim 5, characterized in that: Specifically, the following steps are included: S1: Mix the combined functional agent and 10-20 wt% deionized water in a mixing vessel, heat to 50-60℃ and stir until completely homogeneous to obtain a pre-prepared solution; S2: Add the remaining deionized water to the reaction vessel, stir at 120-150 rpm, add the main alkali agent, and then add the organic amine. At this time, control the temperature of the reaction vessel at 35-40℃. After the addition is completed, increase the stirring speed to 250-350 rpm and continue stirring for 15-30 minutes to obtain the main solution; S3: Add the pre-prepared solution to the main solution, adjust the speed to 150-200 rpm, and slowly add the remaining raw materials in sequence. After the addition is completed, increase the stirring speed to 350-450 rpm and continue stirring for 20-30 minutes to ensure that all components are completely dissolved and mixed evenly to form a uniform and transparent solution. Then lower the temperature of the solution to 20-25℃ and mature under these mild stirring conditions for 2-4 hours. The final product is obtained after this process.

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