Film stripping liquid suitable for dry film after plasma treatment and use method of film stripping liquid

Abstract

The invention discloses a film stripping liquid suitable for a dry film after plasma treatment. The film stripping liquid comprises the following components in percentage by mass: 1-3% of inorganic alkali, 5-20% of organic alkali, 2-6% of an organic solvent, 3.6-6% of a composite penetrant and the balance of water, wherein the composite penetrating agent is a composition of 2-amino-2-methyl-1-propyl alcohol, a surfactant containing a polyamino gemini sulfonate and a gemini surfactant containing a benzimidazolyl group. According to the film stripping liquid provided by the invention, the problems that a high-crosslinking-degree dry film subjected to plasma treatment in an mSAP process is difficult to remove thoroughly and residual copper is easy to appear in a subsequent flash etching process due to a traditional film stripping liquid are solved. The invention further provides a using method of the film stripping liquid, and when the film stripping liquid is applied to stripping of a dry film, the dry film can be dissolved and removed in a direct soaking mode.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit board stripping technology, in particular to a stripping solution for dry film after plasma treatment and a use method thereof. BACKGROUND

[0002] With the development of electronic products towards high density, high performance and miniaturization, the line precision requirements of printed circuit boards (PCB) are increasingly improved. The modified semi-additive process (mSAP) has become the mainstream process of high-end PCB manufacturing (such as IC carrier board) because it can manufacture ultra-fine lines with line width / line spacing below 30 μm. The general process flow includes pre-treatment before lamination, lamination, exposure, development, electroplating, stripping and flash etching.

[0003] However, in the exposure and development process, due to the certain thickness of the photosensitive film, the light will also be scattered to a certain extent when the dry film is exposed, which will result in a transition area at the edge of the line pattern. The photosensitive film in the transition area receives a certain amount of light energy, but the solidification is not complete. A part of the photosensitive film will be left on the bottom of the line during development. The existence of the photosensitive film edge will affect the uniformity of the subsequent electroplating process and the line formation precision, resulting in line defects or performance fluctuations. To address this challenge, some manufacturers have introduced plasma treatment technology. For example, the invention patent CN 103391686 B discloses a circuit board processing method, which uses O2, N2 or Ar plasma to effectively remove the development residual edge through physical bombardment and chemical reaction mechanisms, which can significantly improve the processing precision of the line pattern.

[0004] The main mechanisms of removing the edge by using plasma treatment (gas such as O2, N2, Ar) include:

[0005] (1) Physical bombardment

[0006] High-energy ions (such as Ar+) impact the dry film surface, which strips the residual material through momentum transfer, similar to microscopic sandblasting;

[0007] (2) Chemical reaction

[0008] Active free radicals (such as O . ) react with dry film organic matter (C, H compounds) to generate volatile products (CO2, H2O, etc.), and the reaction process is shown as follows:

[0009]

[0010] However, the plasma treatment not only removes the burrs, but also further crosslinks the cured dry film due to the high temperature and active free radicals inside the plasma, resulting in a more compact structure and a decrease in surface wettability. This problem is particularly prominent in the mSAP process, as the dry film layer is often sandwiched between fine lines, forming a so-called "sandwich film" structure, making it difficult for conventional stripping agents to effectively penetrate and completely remove the dry film.

[0011] There are many existing technologies for conventional process line board stripping agents. For example, Chinese patent CN101957565A discloses an organic stripping agent that can quickly strip the "sandwich film" dry film through the synergistic effect of organic base, chloride salt, and sorbitol. Chinese patent CN113913187A discloses a stripping agent and its preparation method and use method, which combines benzyl alcohol, diethanolamine, sodium sulfate, ethanolamine, pH adjuster, and ethyl imidazole in a specific ratio to increase the stripping speed by 30% compared to traditional inorganic alkali stripping agents. Chinese patent CN113150878A discloses an IC carrier plate film remover and its application, which is composed of two components A and B and water. Component A includes organic base, inorganic base, and penetrating agent (dimethylamine and ethylene glycol monobutyl ether), and component B includes wetting dispersant (polyoxypropylene glycerol ether, dimethyl phosphoric acid aminomethyl sulfonic acid, and sodium sulfonate mixture), surfactant (N-lauroyl sarcosine, etc.). By compounding components A and B, the film layer can be completely removed without curling and sticking.

[0012] However, these stripping agents still have unsatisfactory stripping effects on high-crosslinking dry films after plasma treatment, and generally have the problems of incomplete stripping and residue.

[0013] In addition, traditional stripping agents often contain organic corrosion inhibitors, such as mercaptobenzothiazole (MBT) and benzotriazole (BTA), to prevent copper oxidation. Although these corrosion inhibitors can reduce corrosion by forming a protective film on the copper surface, their residues can hinder the uniformity of subsequent flash etching, leading to local copper residue and incomplete etching. The copper residue problem often requires secondary etching correction, which not only increases process time and cost, but also may reduce the overall etching factor, affecting line width precision and circuit performance stability. SUMMARY

[0014] To solve the problems of difficult complete removal of high-crosslinking dry films after plasma treatment in the mSAP process and the subsequent flash etching process caused by traditional stripping agents, the present application provides a stripping agent for dry films after plasma treatment and a use method thereof.

[0015] The technical solution of the present application is:

[0016] A stripping solution for dry film after plasma processing, characterized in that it comprises the following components in mass percentage: 1-3% inorganic base, 5-20% organic base, 2-6% organic solvent, 3.6-6% composite penetrant, and the balance water.

[0017] The composite penetrant is a combination of 2-amino-2-methyl-1-propanol (AMP-95), polyamine-based gemini sulfonate surfactant, and benzimidazole-based gemini surfactant.

[0018] Further, the mass percentage of 2-amino-2-methyl-1-propanol in the composite penetrant is 0.5-1%, the mass percentage of polyamine-based gemini sulfonate surfactant is 2.1-3%, and the mass percentage of benzimidazole-based gemini surfactant is 1-2%.

[0019] More preferably, the mass percentage ratio of 2-amino-2-methyl-1-propanol, polyamine-based gemini sulfonate surfactant, and benzimidazole-based gemini surfactant in the composite penetrant is 1:(3.5-4):(1.5-2).

[0020] 2-amino-2-methyl-1-propanol (AMP-95) is a multifunctional organic base additive. The amine group and hydroxyl group in the 2-amino-2-methyl-1-propanol molecule endow it with excellent polarity and hydrogen bond formation ability. It can quickly penetrate into the deep layer of dry film and the film / copper interface, destroy the intermolecular force of dry film polymer chains, and initiate the rapid swelling of dry film, creating a channel for subsequent chemical decomposition. At the same time, 2-amino-2-methyl-1-propanol can also enhance the dispersion ability of the stripping solution system for organic debris, helping to improve the solution's carrying capacity of pollutants and prolong the service life of the solution.

[0021] Further, the polyamine-based gemini sulfonate surfactant is GAS, and its structural formula is shown in Chemical Formula (I):

[0022] Chemical Formula (I) is ;

[0023] The preparation method of the GAS is a prior art, which includes the following steps:

[0024] 1. Preparation of intermediates

[0025] In a three-necked flask equipped with a condenser, 12.77 g of N-tallow triamine and 75 ml of isopropyl alcohol were added, and after stirring until the raw material was dissolved, 7.587 g of 3-chloro-2-hydroxypropane sulfonic acid sodium was dissolved in water and prepared into a 25% aqueous solution, and slowly added dropwise to the alcohol solution of N-tallow triamine, after the dropwise addition was completed, the temperature was raised to 60 DEG C, and the system was kept at a constant temperature for 8 h, while adjusting the pH to about 10 with a NaOH solution. After the reaction was completed, isopropyl alcohol, water and residual tallow triamine were removed by distillation under reduced pressure, and the obtained light yellow viscous material was the intermediate.

[0026] 2. Preparation of the multi-amine-containing gemini sulfonate surfactant GAS.

[0027] 10.86 g of the intermediate and 40 mL of water were weighed into a three-necked flask, and stirred at 60 DEG C until uniform, and 10 mL of a 2 mol / L NaOH solution was added. The temperature was raised to 80 DEG C, and 40 mL of an alcohol solution containing 1.785 g (0.0095 mol) of dibromoethane was slowly added dropwise (about 0.5 h), and the reaction was continued for 48 h. After the reaction was completed, the ethanol-water mixed solvent and unreacted dibromoethane were removed by rotary evaporation, 50 mL of ethanol was added, and dissolved while hot, the unreacted NaOH was filtered, then the ethanol was distilled off, and the product was recrystallized from methanol-chloroform three times, to obtain a light yellow paste of the gemini surfactant GAS, and the main reaction formula is shown below:

[0028] The synthesized GAS of the present application has both hydrophilic head groups and hydrophobic chains, and a multi-amine bridging structure, and has a unique molecular structure, which can achieve the synergistic effect and stability that traditional surfactants cannot achieve. The double hydrophobic chains provide stronger hydrophobic force, and can more closely adsorb on the interface between the dry film and the stripping solution, thereby strengthening the penetration, wetting and stripping effect of the stripping solution system; further, the GAS main chain has multiple amine groups, which synergistically act with other components in the stripping solution to promote the hydrolysis, swelling and dissolution of the dry film; the sulfonic acid group in the GAS is a strong hydrophilic group, to ensure the stability and solubility of the GAS in a strong alkaline aqueous solution.

[0029] In addition, the GAS can effectively capture, wrap and stabilize the dry film fragments stripped off, prevent them from re-sticking to the copper surface, thereby ensuring the stripping speed and uniformity, and ultimately ensuring the quality of the circuit board.

[0030] Further, the benzimidazole group-containing gemini surfactant is BG, and its structural formula is shown in chemical formula (II):

[0031] Chemical formula (II) is ;

[0032] The preparation method of the BG refers to Chinese patent CN 120058617 A, which mainly includes the following steps:

[0033] In 50 g of DMSO, equimolar proportions of o-phenylenediamine 10.8 g (0.1 mol) and cinnamaldehyde 13.2 g (0.1 mol) were mixed, 0.1 g of boric acid was used as a catalyst, and the temperature was raised to 55°C for 5 h, and then the solid product was precipitated in an ice water bath to obtain styryl benzimidazole. 22 g (0.1 mol) of styryl benzimidazole was added dropwise into 5 g (0.05 mol) of methyl dioxolane, and 0.12 g of KOH catalyst was fully mixed and stirred at room temperature, first raised to 50°C for 2 h, and then raised to 75°C for 3.5 h to obtain an intermediate product containing compound III. Gaseous SO3 was diluted to 10% by volume to obtain a mixed gas, and the mixed gas was passed into the intermediate product containing compound III according to a molar ratio of SO3 to compound III of 2:1, and the temperature was controlled at 45°C for 3 hours to sulfonate the benzimidazolyl diol intermediate synthesized in the previous step to obtain an intermediate product containing compound II. After the reaction was completed, the pH of the intermediate product containing compound II was adjusted to neutral with 25% ammonia water, and the product was dried and recrystallized from acetone to obtain benzimidazolyl gemini surfactant BG, and the main reaction formula is as follows:

[0034] The benzimidazolyl gemini surfactant BG of the present application realizes multiple function synergies through the symmetrical gemini structure formed by styryl, benzimidazole and sulfonic acid groups, which is specifically manifested in that two hydrophilic head groups and hydrophobic groups significantly reduce the surface tension of the stripping solution, so that the stripping solution system can quickly spread and infiltrate on the surface of the high cross-linking degree dry film, and the infiltration efficiency on the high cross-linking density dry film is improved; at the same time, the benzimidazole group can be coordinated with the copper surface through the nitrogen atom, so that it can form a dense protective film on the copper surface to prevent the copper surface from being oxidized or discolored, and due to the double hydrophilic head groups (sulfonic acid groups) of BG, it has good water solubility, so that it can be completely removed by pure water after stripping, which avoids the problem of residual copper after flash corrosion caused by the residual of traditional corrosion inhibitors (such as MBT).

[0035] Further, the organic base includes at least one of tetramethylguanidine and 1,8-diazabicycloundec-7-ene (DBU).

[0036] Further, the inorganic base includes at least one of sodium hydroxide and potassium hydroxide.

[0037] The inorganic base in the film stripping solution of the present application is mainly to provide a stable alkaline environment for other components, so that each component is more stable in the film stripping solution, which can slow down the decay rate of each component and prolong the service life of the film stripping solution; on the other hand, it can avoid uneven film stripping or residue caused by pH fluctuation, and the pH of the film stripping solution of the present application is 12-13. The organic base tetramethyl guanidine and DBU also have strong alkalinity, can quickly saponify and neutralize the ester group and carboxyl group on the molecular chain of the dry film, quickly destroy the molecular chain, and make the dry film quickly crack.

[0038] Further, the organic solvent includes at least one of N-formyl morpholine, 1,3-dimethyl-2 imidazolinone, N,N-dimethyl acetoacetamide; these organic solvents are high-performance polar solvents, with weak alkalinity and strong penetration, which can quickly penetrate the molecular chain of the dry film, assist the above-mentioned organic base to break the molecular chain of the dry film, and at the same time, the solvent effect effectively dissolves and disperses the reaction product.

[0039] The present application also provides a use method of the film stripping solution suitable for the dry film after plasma treatment, characterized in that the substrate to be stripped is soaked in the film stripping solution provided by the present application, the soaking temperature is 50-65℃, and the soaking time is 1-5min, which can effectively remove the high cross-linking degree dry film after plasma treatment.

[0040] The present application has the following beneficial technical effects:

[0041] Although the plasma treatment improves the line precision, it also increases the cross-linking density of the dry film and makes the structure more compact, and the wettability of the dry film surface is reduced. To solve this technical problem, the present application provides a film stripping solution suitable for the dry film after plasma treatment, in which the inorganic base mainly provides a stable alkaline environment for the system, so that other components can stably and efficiently play a role; the organic base accelerates the breaking of the molecular chain of the dry film under the synergistic action of the organic solvent, so that the dry film is quickly cracked; the composite penetrant strengthens the penetration and wetting effect of the film stripping solution system, so that the film stripping solution can quickly spread and infiltrate on the surface of the dry film, and the 2-amino-2-methyl-1-propanol (AMP-95) and GAS in the composite penetrant further accelerate the film breaking speed under the synergistic action of the organic base, so as to realize the efficient removal of the dry film after plasma treatment.

[0042] In addition, the BG containing a double benzimidazole group in the present application can be coordinated with the copper surface through the nitrogen atom, so that it can form a dense protective film on the copper surface to prevent the copper surface from being oxidized, and due to the good water solubility of BG, it can be completely removed by water washing after film stripping, which solves the problem of residual copper after flash etching caused by the difficulty in removing the film layer formed by the traditional corrosion inhibitor and the copper surface. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1are the micrographs of the results of the film peeling test of each sample plate corresponding to Example 2; wherein 1a is the micrograph of the sample plate M1-P corresponding to Example 2 after the film peeling test, 1b is the micrograph of the sample plate M2-P corresponding to Example 2 after the film peeling test, and 1c is the micrograph of the sample plate M3 corresponding to Example 2 after the film peeling test (magnification x 100);

[0044] Figure 2 are the micrographs of the results of the film peeling test of each sample plate corresponding to Comparative Example 6; wherein 2a is the micrograph of the sample plate M1-P corresponding to Comparative Example 6 after the film peeling test, 2b is the micrograph of the sample plate M2-P corresponding to Comparative Example 6 after the film peeling test, and 2c is the micrograph of the sample plate M3 corresponding to Comparative Example 6 after the film peeling test (magnification x 100);

[0045] Figure 3 are the micrographs of the results of the film peeling test of each sample plate corresponding to Comparative Example 9; wherein 3a is the micrograph of the sample plate M1-P corresponding to Comparative Example 9 after the film peeling test, 3b is the micrograph of the sample plate M2-P corresponding to Comparative Example 9 after the film peeling test, and 3c is the micrograph of the sample plate M3 corresponding to Comparative Example 9 after the film peeling test (magnification x 100);

[0046] Figure 4 are the micrographs of the results of the film peeling test of each sample plate corresponding to Comparative Example 12; wherein 4a is the micrograph of the sample plate M1-P corresponding to Comparative Example 12 after the film peeling test, 4b is the micrograph of the sample plate M2-P corresponding to Comparative Example 12 after the film peeling test, and 4c is the micrograph of the sample plate M3 corresponding to Comparative Example 12 after the film peeling test (magnification x 100);

[0047] Figure 5 are the micrographs of the results of the film peeling test of each sample plate corresponding to Comparative Example 14; wherein 5a is the micrograph of the sample plate M1-P corresponding to Comparative Example 14 after the film peeling test, 5b is the micrograph of the sample plate M2-P corresponding to Comparative Example 14 after the film peeling test, and 5c is the micrograph of the sample plate M3 corresponding to Comparative Example 14 after the film peeling test (magnification x 100);

[0048] Figure 6 is the micrograph of the sample plate M1-P corresponding to Example 2 after the film peeling and flash etching (magnification x 100);

[0049] Figure 7 is the micrograph of the sample plate M2-P corresponding to Example 2 after the film peeling and flash etching (magnification x 100);

[0050] Figure 8is a microphotograph (×100) of the sample M3 corresponding to Example 2 after stripping and flash etching;

[0051] Figure 9 is a microphotograph (×100) of the sample M3 corresponding to Comparative Example 14 after stripping and flash etching;

[0052] Figure 10 is a microphotograph (×100) of the sample M3 corresponding to Comparative Example 15 after stripping and flash etching;

[0053] Figure 11 is a microphotograph (×100) of the sample M3 corresponding to Comparative Example 16 after stripping and flash etching.

[0054] Wherein: 100, copper plated surface; 200, base surface; 300, residual copper bright surface. DETAILED DESCRIPTION

[0055] In order to more clearly understand the technical means of the present application, and can be implemented according to the content of the specification, the following specific embodiments of the present application are further described in detail, the following examples are used to illustrate the present application, but not to limit the scope of the present application.

[0056] In the following examples and comparative examples, the preparation method of the stripping solution includes the following steps: mixing the corresponding raw materials of each component in water.

[0057] The present application provides a stripping solution for dry film after plasma treatment, which comprises the following components by mass percentage: 1-3% inorganic alkali, 5-20% organic alkali, 2-6% organic solvent, 3.6-6% composite penetrant and the balance of water; the composite penetrant is a combination of 2-amino-2-methyl-1-propanol (AMP-95), polyamine-containing gemini sulfonate surfactant and benzimidazole-containing gemini surfactant, and the pH of the stripping solution system of the present application is 12-13.

[0058] The polyamine-containing gemini sulfonate surfactant is GAS, and its structural formula is shown in Chemical Formula (I):

[0059] Chemical Formula (I) is .

[0060] The benzimidazole-containing gemini surfactant is BG, and its structural formula is shown in Chemical Formula (II):

[0061] Chemical Formula (II) is .

[0062] Table 1. Each component and its content of the stripping solution of Examples 1-9 (unit: mass percentage %)

[0063] Table 2. Each component of the stripping solution of Comparative Examples 1-13 and the content (unit: mass percentage ratio %)

[0064] The stripping solution of Comparative Examples 14-16 in Table 3 is prior art.

[0065] Table 3. Each component of the stripping solution of Comparative Examples 14-16 and the ratio

[0066] The stripping solutions of Examples 1-9 and Comparative Examples 1-16 were subjected to stripping tests, and the stripping test of the present application included:

[0067] (1) Preparation of a sample plate

[0068] The sample plate M1-P, the sample plate M2-P and the sample plate M3 used in the stripping test of the present application are all IC carrier plates, with the same bottom copper, electroplated copper and film thickness, and all cut to a size of 2 cm x 2 cm, wherein:

[0069] The sample plate M1-P has a line width / line spacing size of 14 μm / 14 μm, is prepared by the mSAP process and contains plasma treatment, and the process flow is: pre-film pressing treatment- film pressing- exposure- development- plasma treatment- electroplating;

[0070] The sample plate M2-P has a line width / line spacing size of 36 μm / 36 μm, and the process flow for its preparation is the same as that of the sample plate M1-P, containing plasma treatment;

[0071] The sample plate M3 has a line width / line spacing size of 14 μm / 14 μm, is prepared by the mSAP process and does not contain plasma treatment, and the process flow is: pre-film pressing treatment- film pressing- exposure- development- electroplating;

[0072] This design aims to compare and investigate the removal ability of the stripping solution for different fine lines and dry films with and without plasma treatment.

[0073] (2) Stripping test

[0074] The stripping test of the present application all adopts the immersion method, and the stripping solution is prepared in a beaker according to the formula ratio of each example and comparative example. The beaker is placed in a 55℃ constant temperature water bath to maintain a constant reaction temperature; the sample plate to be tested is placed in the beaker and soaked, and the test sample plate is taken out when the film layer is completely removed or the soaking time reaches 300 s, washed with pure water and blown dry.

[0075] Effect evaluation: observe and record the film stripping condition of each sample, including: film clamping condition, film stripping time and copper surface color after film stripping (used for preliminary judgment of whether there is oxidation or corrosion).

[0076] (3) Residual copper detection

[0077] The effect of the film stripping solution on the subsequent flash etching process was not evaluated, and the sample after the film stripping solution film stripping treatment of the corresponding examples and comparative examples was subjected to flash etching process and residual copper inspection:

[0078] Flash etching process: the sample after film stripping and pure water washing was subjected to subsequent flash etching according to the mSAP process flow. Among them, the etching solution used in the flash etching process was: BTH-5600 (provided by Kunshan Banming Electronic Technology Co., Ltd.), and the flash etching time was 2 min.

[0079] Residual copper inspection: after the completion of flash etching, whether there is a local copper layer that has not been etched off (i.e. residual copper) on the substrate after flash etching was checked.

[0080] The film stripping test results of examples 1-9 are shown in Table 4, the film stripping test results of comparative examples 1-13 are shown in Table 5, and the film stripping test results of comparative examples 14-16 are shown in Table 6.

[0081] Table 4. Film stripping test results of examples 1-9

[0082] Table 5. Film stripping test results of comparative examples 1-13

[0083] Table 6. Film stripping test results of comparative examples 14-16

[0084] As can be seen from Table 4, the film stripping solution provided by the present application has good film stripping effect on the sample M3 without plasma treatment, and also has good film stripping effect on the sample M1-P and sample M2-P after plasma treatment. Especially for the high-precision circuit sample M1-P, the film stripping solution provided by the present application can realize the dissolution and shedding of dry film in a short time (in 76-92s), without any film clamping phenomenon; at the same time, the film stripping solution does not react with the copper surface, showing good corrosion inhibition effect, which can effectively protect the integrity of the circuit board. For the sample M2-P with relatively wide circuit, the film stripping time is further shortened to 79-84s.

[0085] In contrast, the stripping solution of Comparative Example 1-13 cannot play a synergistic effect due to improper or missing content ratio of a certain component, and it has different degrees of functional defects in the stripping test results of the sample M1-P, the sample M2-P and the sample M3, such as film clamping, copper surface corrosion or significantly prolonged stripping time.

[0086] The reason is that after plasma treatment, the crosslinking density of the dry film increases, the structure is more compact, and the surface wettability decreases. In the stripping solution system of the present application, the organic base (tetramethyl guanidine, DBU) in the organic solvent (such as N-formyl morpholine, etc.) can effectively and quickly destroy the molecular chain of the dry film and accelerate its cracking; further, AMP-95 in the composite penetrant is a multifunctional organic base additive that can quickly penetrate into the deep layer of the dry film and the film / copper interface, destroy the interchain force of the dry film polymer, and initiate the dry film to swell rapidly, creating a channel for subsequent chemical decomposition; the polyamine-based gemini sulfonate surfactant GAS and the benzimidazole-based gemini surfactant BG both have a special structure with two hydrophilic head groups and two hydrophobic chains, and their synergistic effect can achieve the synergistic effect and stability that traditional surfactants cannot achieve. On the one hand, GAS and BG together strengthen the penetration and wetting effect of the stripping solution system, so that the stripping solution can quickly spread and wet on the surface of the dry film, improving the wetting efficiency of the dry film with high crosslinking density; on the other hand, GAS has multiple amine groups in its main chain, which synergistically act with other components in the stripping solution to promote the hydrolysis, swelling and dissolution of the dry film, and GAS can effectively capture, wrap and stabilize the dry film fragments that have peeled off, ensuring that the dry film fragments do not stick to the copper surface, thereby ensuring the stripping speed and uniformity, and ultimately ensuring the quality of the circuit board; the BG with double benzimidazole groups can form a dense protective film on the copper surface through coordination with the copper surface, preventing the oxidation of the copper surface, and its good water solubility allows it to be completely removed by water washing after stripping, avoiding the problem of residual copper caused by the residue of traditional corrosion inhibitors.

[0087] Comparative Examples 14-16 are prior art, which can effectively remove the dry film on the sample M3 that has not been treated by plasma, but for the sample M1-P and the sample M2-P treated by plasma, even if soaked for 300s, it still cannot achieve complete film removal.

[0088] In view of the problems of incomplete stripping, film clamping, copper surface corrosion or too long time in the above stripping test of Comparative Examples 1-13, and the inability of Comparative Examples 14-16 to handle the plasma-treated samples, these comparative examples do not have practical application value, so no subsequent residual copper test evaluation is performed.

[0089] The present application further carried out subsequent flash etching process on all the samples treated in Examples 1-9 and the sample M3 treated in Comparative Examples 14-16 to detect whether the stripping solution of each relevant example and comparative example produces residual copper phenomenon. Each sample after flash etching was observed under microscope (100 times), and the residual copper detection results are shown in Tables 7 and 8. To avoid redundancy, the present application takes the microscopic magnification pictures of sample M1-P, sample M2-P and sample M3 after flash etching corresponding to Example 2, and the microscopic magnification pictures of sample M3 after flash etching corresponding to Comparative Examples 14-16 as example pictures, which are shown in Figures 6 to 11 .

[0090] Table 7. Residual copper detection results of Examples 1-9

[0091] Table 8. Residual copper detection results of Comparative Examples 14-16

[0092] Figures 6 to 11 In the above-mentioned microscopic pictures, the brass-colored part is the copper-plated surface 100, and the dark-colored part is the substrate surface 200 after flash etching. As can be seen from the microscopic pictures of Tables 7-8 and Figures 6 to 8 , the samples M1-P, sample M2-P and sample M3 treated by the stripping solution of Examples 1-9 do not appear residual copper phenomenon after completing the stripping process and subsequent flash etching process. As can be observed from Figures 6 to 8 , the substrate surface 200 is uniform in color and does not have any copper-colored doped or residual copper layer.

[0093] In contrast, although the stripping solution of Comparative Examples 14-16 avoids copper surface corrosion by relying on traditional corrosion inhibitors during the stripping process, the residual corrosion inhibitors cause significant residual copper problem. As can be seen from the substrate surface 200 of Figures 9 to 11 , the substrate surface 200 of each sample M3 has different degrees of residual copper bright surface 300, which is the residual copper layer that is not etched after flash etching. The reason is that:

[0094] The traditional corrosion inhibitors containing nitrogen-containing heterocyclic compounds and sulfur-containing compounds have relatively single function, which mainly prevent corrosion by forming a strongly adsorbed protective film on the copper surface. However, such protective film is often dense and difficult to be completely removed by conventional water washing, and the residues will hinder the full contact between the subsequent flash etching solution and the copper layer, resulting in uneven etching and forming residual copper.

[0095] The benzimidazolyl gemini surfactant adopted in the application can be coordinated with the copper surface through nitrogen atom to form an effective protective film to prevent copper surface from being oxidized in the film stripping process; meanwhile, the unique gemini structure (double hydrophilic head group and double hydrophobic chain) endows the gemini surfactant with excellent water solubility, which enables the gemini surfactant to be completely removed through conventional water washing after film stripping, thus avoiding the problem of uneven flash corrosion caused by inhibitor residue and fundamentally eliminating the hidden danger of residual copper.

[0096] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. It should be pointed out that, for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A stripper for dry film after plasma treatment, characterized by, The composition comprises the following components in percentage by mass: 1-3% of inorganic base, 5-20% of organic base, 2-6% of organic solvent, 3.6-6% of composite penetrant, and the balance of water. The composite penetrant is a combination of 2-amino-2-methyl-1-propanol, polyamine group-containing gemini sulfonate surfactant, and benzimidazole group-containing gemini surfactant.

2. The stripping solution according to claim 1, wherein the stripping solution is used for a dry film after plasma treatment. The percentage by mass of 2-amino-2-methyl-1-propanol in the composite penetrant is 0.5-1%, the percentage by mass of polyamine group-containing gemini sulfonate surfactant is 2.1-3%, and the percentage by mass of benzimidazole group-containing gemini surfactant is 1-2%.

3. The stripping solution according to claim 2, wherein the stripping solution is used for a dry film after plasma treatment. The mass percentage ratio of 2-amino-2-methyl-1-propanol, polyamine group-containing gemini sulfonate surfactant, and benzimidazole group-containing gemini surfactant in the composite penetrant is 1:(3.5-4):(1.5-2).

4. The stripping solution for dry films after plasma treatment according to claim 1, characterized in that, The polyamine group-containing gemini sulfonate surfactant is GAS, and its structural formula is shown in Chemical Formula (I). Chemical formula (I) is .

5. The stripping solution of claim 1, wherein the stripping solution is suitable for use with a dry film after plasma treatment. The benzimidazole group-containing gemini surfactant is BG, and its structural formula is shown in Chemical Formula (II). Chemical formula (II) is .

6. The stripping solution of claim 1, wherein the stripping solution is suitable for use with a dry film after plasma treatment. The organic base comprises at least one of tetramethylguanidine and 1,8-diazabicycloundec-7-ene (DBU).

7. The stripping solution of claim 1, wherein the stripping solution is suitable for use with a dry film after plasma treatment. The inorganic base comprises at least one of sodium hydroxide and potassium hydroxide.

8. The stripping solution of claim 1, wherein the stripping solution is suitable for use with a dry film after plasma treatment. The organic solvent comprises at least one of N-formylmorpholine, 1,3-dimethyl-2-imidazolidinone, and N,N-dimethylacetamide.

9. The method of using a de-molding solution according to any one of claims 1-8, wherein, The substrate to be stripped is soaked in the stripping solution as claimed in any one of claims 1-8 at a temperature of 50-65°C for 1-5 min.

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