Acidic stripping solution, stripping solution and application of PCB fine line

Abstract

The application discloses a PCB fine line acid stripping solution, a stripping solution and application, and relates to the technical field of printed circuit board manufacturing. The PCB fine line acid stripping solution comprises the following components in mass concentration: 10.0-16.0% of a main solvent; 2.0-4.0% of a penetrant; 2.0-4.0% of an environmental regulator; 0.5-1.0% of a metal corrosion inhibitor; 0.4-1.0% of a wetting homogenizing agent; and the balance of water. The PCB fine line acid stripping solution can quickly penetrate and swell the dry film, accelerates the stripping time, effectively prevents the risks of'sandwiching the film' and 'penetration plating', has a low working temperature, can reduce energy consumption, has a low corrosion rate on the copper surface and a low line width deviation, and is suitable for the process requirements of PCB fine line acid stripping.

Description

Technical Field

[0001] This invention relates to the field of printed circuit board manufacturing technology, and in particular to an acidic stripping solution for fine PCB circuits, a stripping agent, and their applications. Background Technology

[0002] In the manufacturing process of printed circuit boards (PCBs), pattern plating is a crucial step in constructing circuitry. The specific process is as follows: First, a layer of resist dry film is attached to the surface of a copper substrate. After exposure and development, the patterned areas to be plated are exposed. Subsequently, copper and tin are deposited onto these exposed areas through an electroplating process. After the electroplating process is completed, the dry film protecting the non-plated areas must be completely removed; this step is defined as "film removal."

[0003] The current PCB manufacturing is moving towards high density and precision. The line width and spacing of the circuits have been reduced from more than 100μm to less than 50μm, and some high-end products have even reached the 20μm level. This trend has put forward three extremely high requirements for the stripping process: (1) The dry film must be completely removed. A trace amount of residual dry film will cause "penetration" or "film trapping" defects in subsequent processes, eventually leading to short circuits or open circuits. (2) Traditional alkaline stripping solutions will corrode the electroplated metal under high temperature and high alkalinity conditions, causing lateral corrosion, which will affect the accuracy and electrical performance of the circuit. (3) Commonly used alkaline stripping solutions have high operating temperatures, which not only consume a lot of energy, but also the amines they contain are volatile and produce an irritating odor, which will affect the working environment.

[0004] Acidic stripping solutions have become a key process in fine circuit manufacturing due to their two core advantages: they can efficiently remove alkali-resistant photoresist and are compatible with subsequent metallization hole pretreatment processes. Although there are reports on acidic stripping solutions in existing technologies, these products generally have three major problems: First, the stripping efficiency is low, especially in complex structural areas such as blind vias and micro-vias in fine circuits, where the stripping solution has insufficient penetration and easily leaves photoresist residue, which can cause defects such as plating voids and peeling during subsequent electroplating; second, it severely corrodes the copper surface, and fine circuits are prone to linewidth deviations exceeding 5μm due to corrosion, or even line breakage, resulting in low product yield; third, it has poor substrate compatibility, and the substrate is prone to surface whitening and high weight loss after use, which in turn affects the mechanical strength and insulation performance of the substrate.

[0005] Existing technologies also include several methods for removing PCB protective films. Patent CN117343733A describes a stripping agent for the organic protective film on the copper surface of printed circuit boards and its preparation method. This agent can effectively remove newly prepared organic protective films from the copper surface of printed circuit boards and can also effectively remove various stains from the copper surface of printed circuit boards during normal production. However, its effect on removing dry film is poor, easily resulting in dry film residue. Patent CN114554707B provides a stripping process for high-precision circuit boards. This solution offers fast stripping speed, long bath life, and clean stripping without causing dry film residue. It is suitable for stripping fine circuits, IC substrates, and MSAP processes. However, this component has a high alkali content, which can corrode metals. Additionally, its high ammonia nitrogen content is detrimental to environmental pollution.

[0006] Therefore, the present invention aims to provide a novel acidic stripping solution specifically designed for fine PCB circuitry. This stripping solution enables rapid, thorough, and non-destructive peeling of the dry film on the surface of fine PCB circuitry under mild acidic conditions, while also offering advantages such as operational safety and environmental friendliness. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides an acidic stripping solution for fine PCB circuits, used in the stripping process of fine PCB circuits. This stripping solution mainly contains a main solvent, penetrant, environmental conditioner, metal corrosion inhibitor, and wetting homogenizer, among other effective components. The main solvent has a strong dissolving ability for the dry film resin, which is key to achieving rapid stripping. The penetrant significantly reduces the surface tension of the solution, working synergistically with the main solvent to quickly penetrate to the bottom layer of the dry film and deep into the micropores, preventing residue. The environmental conditioner provides a mild acidic environment, avoiding damage to the metal circuitry. Under acidic conditions, the metal corrosion inhibitor forms a dense polymeric protective film on the copper surface, effectively preventing metal corrosion and greatly reducing lateral corrosion. The wetting homogenizer further improves the spreadability and wetting uniformity of the solution on complex circuit structures, ensuring consistent stripping.

[0008] The purpose of the invention is achieved through the following technical solutions.

[0009] A fine-line acidic stripping solution for PCBs is provided, comprising the following components by mass concentration:

[0010] Main solvent 10.0–16.0%;

[0011] Penetrant 2.0–4.0%;

[0012] Environmental conditioner 2.0–4.0%;

[0013] Metal corrosion inhibitor 0.5–1.0%;

[0014] Wetting and homogenizing agent 0.4–1.0%;

[0015] The remainder is water;

[0016] The main solvent is selected from one or more mixtures of p-methoxyphenyl glycidyl ether (CAS No.: 2211-94-1), guaiacol glycidyl ether (CAS No.: 2210-74-4), and 4-nonylphenyl glycidyl ether (CAS No.: 6178-32-1);

[0017] The penetrant is selected from one or more mixtures of polyethylene glycol bis(3-chloro-2-hydroxypropyl) ether (CAS No.: 37569-89-4), bisphenol A-bis(3-chloro-2-hydroxypropyl) ether (CAS No.: 4809-35-2), and 4-chlorophenyl glycidyl ether (CAS No.: 2212-05-7);

[0018] The environmental regulator is selected from one or more mixtures of 2-phosphonobutane-1,2,4-tricarboxylic acid (CAS No.: 37971-36-1), phosphoryl succinic acid (CAS No.: 5768-48-9), and 2-carboxyethyl phosphoric acid (CAS No.: 5962-42-5);

[0019] The metal corrosion inhibitor is selected from one or more mixtures of 4-hydroxy-6-methoxymethylpyrimidine-2-thiol (CAS No.: 175205-07-9), 2-amino-6-methylpyrimidine-4-thiol (CAS No.: 6307-44-4), and 4-(2-furanyl)-2-pyrimidinethiol (CAS No.: 190579-95-4);

[0020] The wetting homogenizer is selected from one or more mixtures of trifluoromethanesulfonate (CAS No.: 3582-05-6), 2,2,2-trifluoroethyltrifluoromethanesulfonate (CAS No.: 6226-25-1), and triethylsilanetrifluoromethanesulfonate (CAS No.: 79271-56-0).

[0021] Preferably, the PCB fine circuit acid stripping solution comprises the following components by mass concentration:

[0022] Main solvent 13.0%;

[0023] Penetrant 3.0%;

[0024] Environmental conditioner 3.0%;

[0025] Metal corrosion inhibitor 0.8%;

[0026] Wetting and homogenizing agent 0.6%;

[0027] The remainder is water.

[0028] The preparation method of the above-mentioned acidic stripping solution for fine PCB circuits includes the following steps: weigh the main solvent, penetrant, environmental conditioner, metal corrosion inhibitor and wetting homogenizer in sequence according to the mass concentration ratio, add them to water, and mix them evenly at room temperature to obtain the solution.

[0029] The present invention also provides a stripping solution containing the above-mentioned acidic stripping solution for fine PCB circuits.

[0030] Preferably, the stripping solution contains 5.0-10.0% by mass of the acidic stripping solution for fine PCB circuits, with the remainder being water.

[0031] The present invention also provides the application of the above-mentioned stripping solution, including a stripping process: spraying the electroplated PCB with the stripping solution for 55-65 seconds.

[0032] Preferably, the spray pressure is 2.0 ± 0.1 kg / cm². 2 The temperature of the desiccant solution is 30±0.5℃.

[0033] Furthermore, the process prior to the stripping process includes a pre-immersion process: immersing the electroplated PCB in a pre-immersion solution for 25-35 seconds; the pre-immersion solution contains 3.0-5.0% by mass of the aforementioned acidic stripping solution for fine PCB circuitry, with the remainder being water.

[0034] Furthermore, an acid degreasing process is included before the pre-impregnation process.

[0035] Furthermore, the film removal process is followed by a washing process and a drying process.

[0036] The acidic stripping solution for fine PCB circuits of this invention contains a main solvent, a penetrant, an environmental conditioner, a metal corrosion inhibitor, and a wetting homogenizer. Under the synergistic effect of these components, it can quickly penetrate and swell the dry film, thereby accelerating the stripping time and effectively eliminating the risks of "film trapping" and "plating penetration". At the same time, the stripping working temperature is low, which can reduce energy consumption and make it more environmentally friendly and safe. Moreover, it has a low corrosion rate and low line width deviation on the copper surface, which greatly improves the integrity of the circuit and the consistency of electrical performance, and is suitable for the process requirements of acidic stripping of fine PCB circuits. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a metallographic microscope image of Example 1 after the film was removed;

[0039] Figure 2 This is a metallographic microscope image of Comparative Example 16 after the film has been removed. Detailed Implementation

[0040] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0042] It should be noted that the contents or concentrations mentioned in the following examples / comparative examples are all mass concentrations.

[0043] The preparation method of the PCB fine circuit acid stripping solution in Examples 1-5 is as follows: According to the formula of Examples 1-5, the main solvent, penetrant, environmental conditioner, metal corrosion inhibitor, wetting homogenizer and the balance water are weighed in sequence and added to the reaction vessel. The mixture is stirred and mixed at room temperature for 30 minutes to obtain the PCB fine circuit acid stripping solution of the corresponding example. The obtained PCB fine circuit acid stripping solution is sealed and stored for later use.

[0044] Example 1:

[0045] The acidic stripping solution for fine PCB circuits in this embodiment consists of the following components:

[0046] The main solvent content is 13.0%, specifically: p-methoxyphenyl glycidyl ether;

[0047] The penetrant content is 3.0%, specifically: polyethylene glycol bis(3-chloro-2-hydroxypropyl) ether;

[0048] The environmental conditioner content is 3.0%, specifically 2-phosphonobutane-1,2,4-tricarboxylic acid;

[0049] The metal corrosion inhibitor content is 0.8%, specifically 4-hydroxy-6-methoxymethylpyrimidine-2-thiol;

[0050] The wetting and homogenizing agent content is 0.6%, specifically trifluoromethyl trifluoromethanesulfonate;

[0051] The remainder is water.

[0052] Example 2:

[0053] The acidic stripping solution for fine PCB circuits in this embodiment consists of the following components:

[0054] The main solvent content is 13.0%, specifically: guaiacol glycidyl ether;

[0055] The penetrant content is 3.0%, specifically: bisphenol A-di(3-chloro-2-hydroxypropyl) ether;

[0056] The environmental conditioner content is 3.0%, specifically phosphoryl succinic acid;

[0057] The metal corrosion inhibitor content is 0.8%, specifically 2-amino-6-methylpyrimidine-4-thiol;

[0058] The wetting and homogenizing agent content is 0.6%, specifically 2,2,2-trifluoroethyltrifluoromethane sulfonate;

[0059] The remainder is water.

[0060] Example 3:

[0061] The acidic stripping solution for fine PCB circuits in this embodiment consists of the following components:

[0062] The main solvent content is 13.0%, specifically: 4-nonylphenyl glycidyl ether;

[0063] The penetrant content is 3.0%, specifically: 4-chlorophenyl glycidyl ether;

[0064] The environmental conditioner content is 3.0%, specifically 2-carboxyethyl phosphoric acid;

[0065] The metal corrosion inhibitor content is 0.8%, specifically 4-(2-furanyl)-2-pyrimidinethiol;

[0066] The wetting and homogenizing agent content is 0.6%, specifically triethylsilane trifluoromethane sulfonate;

[0067] The remainder is water.

[0068] Example 4:

[0069] The acidic stripping solution for fine PCB circuits in this embodiment consists of the following components:

[0070] The main solvent content is 10.0%, specifically: p-methoxyphenyl glycidyl ether;

[0071] The penetrant content is 2.0%, specifically: polyethylene glycol bis(3-chloro-2-hydroxypropyl) ether;

[0072] The environmental conditioner content is 2.0%, specifically 2-phosphonobutane-1,2,4-tricarboxylic acid;

[0073] The metal corrosion inhibitor content is 0.5%, specifically 4-hydroxy-6-methoxymethylpyrimidine-2-thiol;

[0074] The wetting and homogenizing agent content is 0.4%, specifically trifluoromethyl trifluoromethanesulfonate;

[0075] The remainder is water.

[0076] Example 5:

[0077] The acidic stripping solution for fine PCB circuits in this embodiment consists of the following components:

[0078] The main solvent content is 16.0%, specifically: p-methoxyphenyl glycidyl ether;

[0079] The penetrant content is 4.0%, specifically: polyethylene glycol bis(3-chloro-2-hydroxypropyl) ether;

[0080] The environmental conditioner content is 4.0%, specifically 2-phosphonobutane-1,2,4-tricarboxylic acid;

[0081] The metal corrosion inhibitor content is 1.0%, specifically 4-hydroxy-6-methoxymethylpyrimidine-2-thiol;

[0082] The wetting and homogenizing agent content is 1.0%, specifically trifluoromethyl trifluoromethanesulfonate;

[0083] The remainder is water.

[0084] Based on Example 1, the film stripping solutions of Comparative Examples 1-15 were prepared; in addition, the film stripping solution of Comparative Example 16 was prepared.

[0085] Comparative Example 1

[0086] The only difference between Comparative Example 1 and Example 1 is that the components do not contain a main solvent.

[0087] Comparative Example 2

[0088] The only difference between Comparative Example 2 and Example 1 is that the components do not contain a penetrant.

[0089] Comparative Example 3

[0090] The only difference between Comparative Example 3 and Example 1 is that the components do not contain environmental regulators.

[0091] Comparative Example 4

[0092] The only difference between Comparative Example 4 and Example 1 is that the components do not contain metal corrosion inhibitors.

[0093] Comparative Example 5

[0094] The only difference between Comparative Example 5 and Example 1 is that the components do not contain a wetting homogenizer.

[0095] Comparative Example 6

[0096] The only difference between Comparative Example 6 and Example 1 is that the concentration of the main solvent in the component is 20.0%.

[0097] Comparative Example 7

[0098] The only difference between Comparative Example 7 and Example 1 is that the concentration of the penetrant in the component is 6.0%.

[0099] Comparative Example 8

[0100] The only difference between Comparative Example 8 and Example 1 is that the concentration of the environmental conditioner in the component is 6.0%.

[0101] Comparative Example 9

[0102] The only difference between Comparative Example 9 and Example 1 is that the concentration of the metal corrosion inhibitor in the component is 2.0%.

[0103] Comparative Example 10

[0104] The only difference between Comparative Example 10 and Example 1 is that the concentration of the wetting homogenizer in the component is 2.0%.

[0105] Comparative Example 11

[0106] The only difference between Comparative Example 11 and Example 1 is that the main solvent component, p-methoxyphenyl glycidyl ether, is replaced with an equal mass of butyl glycidyl ether (CAS No.: 2426-08-6).

[0107] Comparative Example 12

[0108] The only difference between Comparative Example 12 and Example 1 is that the penetrant component, polyethylene glycol bis(3-chloro-2-hydroxypropyl) ether, is replaced with an equal mass of ethylene glycol ethyl methyl ether (CAS No.: 5137-45-1).

[0109] Comparative Example 13

[0110] The only difference between Comparative Example 13 and Example 1 is that the environmental conditioner component, 2-phosphonobutane-1,2,4-tricarboxylic acid, is replaced with an equal mass of phosphoric acid (CAS No.: 7664-38-2).

[0111] Comparative Example 14

[0112] The only difference between Comparative Example 14 and Example 1 is that the metal corrosion inhibitor component, 4-hydroxy-6-methoxymethylpyrimidine-2-thiol, is replaced with an equal mass of propanethiol (CAS No.: 107-03-9).

[0113] Comparative Example 15

[0114] The only difference between Comparative Example 15 and Example 1 is that the wetting homogenizer component, trifluoromethanesulfonate, is replaced with an equal mass of S-methylmethanethiosulfonate (CAS No.: 2949-92-0).

[0115] Comparative Example 16

[0116] Comparative Example 16 is the film stripping solution described in prior art CN117343733A, and its specific components include:

[0117] 12.8% hydrochloric acid;

[0118] 10.4% sulfuric acid;

[0119] 8.4% oxalic acid,

[0120] 0.1% sodium lauryl ether sulfate;

[0121] The remaining water is tap water.

[0122] The above embodiments of the PCB fine circuit acid stripping solution and the comparative example of the stripping solution use methods include the following steps: S1 acid degreasing; S2 water rinsing; S3 pre-immersion; S4 stripping; S5 water rinsing; S6 drying; wherein

[0123] The S1 acidic degreasing section is used to degrease the PCB and remove surface dirt. The process parameters for the acidic degreasing section are as follows: spraying method is used; the solution in the degreasing tank consists of 5.0wt% sulfuric acid and the remainder tap water; the degreasing tank temperature is 30±0.5℃; the length of the degreasing section is 1.0m; the linear velocity is 2.0±0.1m / min; and the pressure is 1.5±0.1kg / cm. 2 ;

[0124] The S2 water washing section involves rinsing the PCBs from the S1 acidic degreasing section with tap water. The process parameters for this section are: spray method, water temperature 30±0.5℃, section length 1.0m, linear velocity 2.0±0.1m / min, and pressure 1.5±0.1kg / cm². 2 ;

[0125] The S3 pre-impregnation section is used to pre-impregnate the PCBs that have passed through the S2 water washing section with pre-impregnation solution. The process parameters of the pre-impregnation section are as follows: immersion method is adopted, the pre-impregnation solution in the pre-impregnation tank contains 3.0wt% of the stripping solution of the example or comparative example, and the balance is tap water; the temperature of the pre-impregnation tank is 30±0.5℃, the length of the pre-impregnation section is 1.0m, and the linear speed is 2.0±0.1m / min.

[0126] The S4 stripping section is used to strip the PCB film from the S3 pre-impregnation section using stripping solution. The process parameters for the stripping section are as follows: spraying method is used; the stripping solution in the pre-impregnation tank contains 6.0 wt% of the stripping solution from the example or comparative example, with the remainder being tap water; the stripping tank temperature is 30±0.5℃; the stripping section length is 2.0m; the linear speed is 2.0±0.1m / min; and the pressure is 2.0±0.1kg / cm. 2 ;

[0127] The S5 water washing section involves rinsing the PCB that has passed through the S4 film removal section with tap water. The process parameters for this water washing section are as follows: spray method, water temperature 30±0.5℃, water washing section length 1.0m; linear speed 2.0±0.1m / min, pressure 1.5±0.1kg / cm. 2 ;

[0128] The S6 drying section is used to dry the PCB after the S5 water washing section. The drying process parameters are: temperature 70±5℃, drying section length 2.0m, and linear speed 2.0±0.2m / min.

[0129] The performance of the PCB fine circuit acid stripping solution of the above embodiments and the stripping solution of the comparative example were tested in the following items;

[0130] 1) The copper surface corrosion rate was tested using the etching method. The specific method was as follows: Take a standard copper-clad laminate with dimensions of 4cm x 5cm and a copper thickness of 5μm. Weigh it using an electronic balance before the test. Treat the laminate according to the stripping solution usage instructions described above. After removing the laminate, record the etching time (min). Then weigh the laminate after the experiment. The copper surface corrosion rate is calculated as weight difference (g) * 28 / etching time, in μm / min. The experimental results require a copper surface corrosion rate greater than or equal to 0.2μm / min.

[0131] 2) Film removal time; The specific method is as follows: Treat the PCB according to the above-mentioned method of using the film removal solution, and observe the time it takes for the dry film on the PCB to completely peel off in the S4 film removal section, in seconds. The experimental results require a film removal time of 28-35 seconds;

[0132] 3) Linewidth deviation; The specific method is as follows: After the PCB has been stripped (the linewidth of the test board is 20μm), select the circuit area to make a slice, and measure the linewidth using an optical microscope. Linewidth deviation = measured linewidth - designed linewidth, in μm. The experimental results require a linewidth deviation < 1.5μm.

[0133] The performance test results of Examples 1-5 and Comparative Examples 1-16 are shown in Table 1 below:

[0134] Table 1 Performance Test Results

[0135]

[0136] Metallographic microscopy observation results of the PCB after film removal in Example 1 are as follows: Figure 1 As shown; the metallographic microscopic observation results of the PCB after film removal in Comparative Example 16 are as follows. Figure 2 As shown.

[0137] As can be seen from the test results of Examples 1-5 in Table 1, the acid stripping solution for fine circuit PCBs of the present invention has excellent stripping performance: the stripping speed is fast, and complete stripping only takes about 30 seconds; the copper surface corrosion rate after stripping is extremely low, only about 0.22 μm / min; in addition, for fine circuit PCBs with a line width of 20 μm, the line width deviation after stripping is only about 0.3 μm, which can meet the process requirements of acid stripping for fine circuit PCBs.

[0138] The difference between the stripping solutions of Comparative Examples 1-5 and Example 1 is the absence of one of the following components: main solvent, penetrant, environmental conditioner, metal corrosion inhibitor, and wetting homogenizer, respectively. Test results show that the main solvent has an extremely strong dissolving ability for the dry film resin and is key to achieving rapid stripping. When the main solvent is absent from the system, the stripping time increases significantly, and it also affects the copper surface corrosion rate and linewidth deviation. The penetrant, environmental conditioner, and wetting homogenizer mainly play auxiliary, regulating, and promoting roles, working synergistically with the main solvent to rapidly penetrate to the bottom layer of the dry film and deep into the micropores, further improving the spreadability and wetting uniformity of the solution on complex circuit structures, ensuring consistent stripping. When any one of the penetrant, environmental conditioner, or wetting homogenizer is absent from the system, the stripping performance indicators such as copper surface corrosion rate, stripping time, and linewidth deviation all show a slight decrease. Metal corrosion inhibitors can form a dense polymeric protective film on the copper surface under acidic conditions, effectively preventing metal corrosion and greatly reducing lateral corrosion. When the metal corrosion inhibitor is lacking in the system, the corrosion rate of the copper surface increases significantly, leading to a substantial increase in linewidth deviation and a slight increase in stripping time. Overall, the acidic stripping solution for fine PCB circuits of this invention achieves its effect through the synergistic effect of all its effective components; none can be omitted.

[0139] The difference between Comparative Examples 6-10 and Example 1 lies in the concentration limits of the main solvent, penetrant, environmental conditioner, metal corrosion inhibitor, and wetting homogenizer in the stripping solution, all of which are higher than those of the stripping solution of this invention. Test results show that, compared to Examples 1-5, even increasing the concentration of these components does not affect the performance of the stripping solution, but significantly increases the preparation cost. Therefore, the components of the stripping solution of this invention do not need to be at excessively high concentrations; as long as the concentrations are controlled within the range described in the examples, the solution can be ensured to have good stripping performance.

[0140] The difference between Comparative Examples 11-15 and Example 1 is that the main solvent, penetrant, environmental conditioner, metal corrosion inhibitor, wetting homogenizer, etc. are replaced with compounds of similar structure / similar function in equal mass. The test results show that the functional components of different types of branched groups also affect the stripping performance, making it difficult to meet the stripping requirements of fine circuit PCBs.

[0141] Comparative Example 16 uses the stripping solution disclosed in the prior art CN117343733A. The experimental results show that the stripping solution of the present invention has better performance in terms of copper surface corrosion rate, stripping time and linewidth deviation.

[0142] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An acidic stripping solution for fine PCB circuits, characterized in that, Components including the following mass concentrations: Main solvent 10.0–16.0%; Penetrant 2.0–4.0%; Environmental conditioner 2.0–4.0%; Metal corrosion inhibitor 0.5–1.0%; Wetting and homogenizing agent 0.4–1.0%; The remainder is water; The main solvent is selected from one or more mixtures of p-methoxyphenyl glycidyl ether, guaiacol glycidyl ether, and 4-nonylphenyl glycidyl ether. The penetrant is selected from one or more mixtures of polyethylene glycol bis(3-chloro-2-hydroxypropyl) ether, bisphenol A-bis(3-chloro-2-hydroxypropyl) ether, and 4-chlorophenyl glycidyl ether; The environmental conditioner is selected from one or more mixtures of 2-phosphonobutane-1,2,4-tricarboxylic acid, phosphoryl succinic acid, and 2-carboxyethyl phosphoric acid; The metal corrosion inhibitor is selected from one or more mixtures of 4-hydroxy-6-methoxymethylpyrimidine-2-thiol, 2-amino-6-methylpyrimidine-4-thiol, and 4-(2-furanyl)-2-pyrimidinethiol; The wetting homogenizer is selected from one or more mixtures of trifluoromethanesulfonate, 2,2,2-trifluoroethyltrifluoromethanesulfonate, and triethylsilanetrifluoromethanesulfonate.

2. The acidic stripping solution for fine PCB circuits according to claim 1, characterized in that, Components including the following mass concentrations: Main solvent 13.0%; Penetrant 3.0%; Environmental conditioner 3.0%; Metal corrosion inhibitor 0.8%; Wetting and homogenizing agent 0.6%; The remainder is water.

3. A method for preparing an acidic stripping solution for fine PCB circuits as described in claim 1 or 2, characterized in that, The process includes the following steps: Weigh the main solvent, penetrant, environmental conditioner, metal corrosion inhibitor, and wetting homogenizer in sequence according to the mass concentration ratio, add them to water, and mix them evenly at room temperature to obtain the final product.

4. A film-removing solution, characterized in that, It contains the acidic stripping solution for fine PCB circuits as described in claim 1 or 2.

5. The film-removing solution according to claim 4, characterized in that, It contains 5.0-10.0% by mass of the acidic stripping solution for fine PCB circuitry, with the balance being water.

6. The application of the film-removing solution as described in claim 4 or 5, characterized in that, The process includes a film removal step: the electroplated PCB is sprayed with a film removal solution for 55-65 seconds.

7. The application according to claim 6, characterized in that, The spray pressure is 2.0 ± 0.1 kg / cm². 2 The temperature of the desiccant solution is 30±0.5℃.

8. The application according to claim 7, characterized in that, The stripping process includes a pre-immersion process before the stripping process: immersing the electroplated PCB in a pre-immersion solution for 25-35 seconds; the pre-immersion solution contains 3.0-5.0% by mass of the acidic stripping solution for fine PCB lines as described in claim 1 or 2, with the remainder being water.

9. The application according to claim 8, characterized in that, The pre-impregnation process is preceded by an acid degreasing process.

10. The application according to claim 9, characterized in that, The film removal process is followed by a washing process and a drying process.

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