A developing etching process for producing a PCB board

Abstract

The application discloses a developing etching process for producing a PCB (Printed Circuit Board), and belongs to the field of PCB processing, which comprises the following steps: S1, using a pre-etching agent to pre-etch the PCB; S2, using an etching-resistant agent to etching-resistantly treat the line sidewall of the PCB after pre-etching; S3, using a main etching agent to etch the PCB after pre-etching after etching-resistant treatment; the pre-etching agent comprises the following components in parts by weight: 30-40 parts of citric acid, 5-8 parts of EDTA, 3-5 parts of a non-ionic or anionic surfactant, and 1-3 parts of a coupling agent; the main etching agent comprises the following components in parts by weight: 40-50 parts of ferric chloride, 10-15 parts of maleic acid, 10-15 parts of an amino acid, 3-5 parts of hydrogen peroxide, 1-3 parts of a pH regulator, and 1-2 parts of a rare earth oxide; the etching-resistant agent is a resin containing a double bond and ethylene glycol dimethyl ether, and the mass ratio of ethylene glycol dimethyl ether to the resin containing a double bond is 1:10. The application can guarantee high-quality etching effect and solve the problem of etching measurement.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of circuit board processing, and relates to a developing and etching process for producing a PCB (Printed Circuit Board). BACKGROUND

[0002] After a printed circuit board with dry film is exposed, a developing and etching process is needed to remove the copper area that does not need to be protected by the dry film; in the prior art, an etchant is used to soak and etch the circuit board, and side etching occurs in the etching process, that is, the circuit board line sidewall is etched, which can cause the actual line width to be smaller than the designed width, and when the side etching is too large, the isolation gap between lines can become small, thereby causing a short circuit risk; excessive side etching can also cause the conductor cross-sectional area to decrease and the resistance to increase, thereby affecting the electrical performance of the circuit and reducing the signal transmission efficiency and current carrying capacity. SUMMARY

[0003] The application aims to provide a developing and etching process for producing a PCB, which solves the problem of etching the circuit board line sidewall in the etching process.

[0004] The technical scheme adopted by the application is as follows:

[0005] A developing and etching process for producing a PCB, comprising the following steps:

[0006] S1, pre-etching the PCB with a pre-etching agent;

[0007] S2, after pre-etching, using an etch-resistant agent to perform etch-resistant treatment on the circuit board line sidewall;

[0008] S3, after etch-resistant treatment, using a main etching agent to etch the PCB after pre-etching;

[0009] The pre-etching agent comprises the following components in parts by weight: 30-40 parts of citric acid, 5-8 parts of EDTA, 3-5 parts of a non-ionic or anionic surfactant, and 1-3 parts of a coupling agent;

[0010] The main etching agent comprises the following components in parts by weight: 40-50 parts of ferric chloride, 10-15 parts of maleic acid, 10-15 parts of an amino acid, 3-5 parts of hydrogen peroxide, 1-3 parts of a pH adjuster, and 1-2 parts of a rare earth oxide;

[0011] The etch-resistant agent is a resin containing a double bond and ethylene glycol dimethyl ether, and the mass ratio of ethylene glycol dimethyl ether to the resin containing a double bond is 1:10.

[0012] The PCB is pre-etched, and after removing the surface oil stains and oxides, the anti-etching treatment of the circuit side wall and the etching treatment of the copper layer are carried out, which can enhance the adhesion of the anti-etching agent and the circuit side wall, and can accelerate the etching efficiency of the etching agent; in addition, the pre-etching agent is modified, the etching degree of the modified pre-etching agent is lower than that of the main etching agent, which can effectively avoid the over-etching of the circuit board by the pre-etching, and the modified pre-etching agent is added with a coupling agent, after pre-etching, the coupling agent will be partially adhered to the circuit side wall, the coupling agent can be used as an interface modifier to strengthen the interface connection strength between the resin in the anti-etching agent and the circuit side wall, so that the anti-etching agent can be firmly adhered to the circuit side wall of the circuit board.

[0013] In the case of ensuring rapid etching, a new main etching agent is designed based on ferric chloride, the main etching agent of the application is mainly composed of ferric chloride, and the strength of ferric chloride is strong, in order to realize the controllable etching degree of the circuit board and avoid over-etching in a very short time, maleic acid and amino acid are added, maleic acid and amino acid are used as corrosion inhibitors, and maleic acid is used as a buffer to help maintain the pH value of the etching solution stable, because it is a reversible dissociation organic acid, it can absorb or release hydrogen ions, so as to adjust the pH value of the etching environment; the amino acid can be adsorbed on the metal surface to form a protective film, this film will also be etched in a certain time, but it can slow down the etching speed of ferric chloride to a certain extent; hydrogen peroxide and pH regulator are common additives for etching agent, which are directly used in the present application; in order to solve the problem of etching of the circuit board circuit side wall, the most important thing is that the rare earth oxide is added to the main etching agent, the rare earth oxide can accelerate the etching speed of copper and other metals due to its unique electronic structure, and can also improve the microtopography of the etching surface, so that the etched circuit is smoother, which is beneficial to improve the electrical performance of the circuit board; the rare earth oxide is added in the application on the one hand to improve the etching speed and effect of the main etching agent, and to maintain balance with amino acid and maleic acid to form a stable etching system with controllable etching degree and high etching efficiency, on the other hand, the rare earth oxide is added to the application to strengthen the strength of the anti-etching layer on the circuit board circuit side wall and improve its anti-etching performance, thereby effectively solving the problem of etching of the circuit board circuit side wall.

[0014] The principle of strengthening the etching effect of the copper layer and the strength of the anti-etching layer of the circuit side wall by the rare earth oxide is that the rare earth oxide, the coupling agent in the pre-etching agent and the anti-etching agent will react under acidic conditions, which can strengthen the strength and etching resistance of the resin in the anti-etching agent, the pre-etching agent and the main etching agent of the application are acidic, which provides the acidic conditions; the specific principle is:

[0015] The reaction mechanism of rare earth, coupling agent and resin containing double bond under acidic conditions and the action of crosslinking agent is:

[0016] 1. Hydrolysis reaction:

[0017] When silane coupling agent (e.g. γ-methacryloxypropyltrimethoxysilane) is exposed to an acidic environment, the alkoxy group (e.g. methoxy) will undergo hydrolysis reaction to form silanol (Si-OH) group;

[0018] For example: RSi(OR')3 + H2O → RSi(OH)3 + 3R'OH

[0019] Where RSi(OR') represents the silane coupling agent, and R'OH is the alcohol produced by hydrolysis.

[0020] 2. Reaction between silanol and rare earth oxide:

[0021] Subsequently, the newly generated silanol group (Si-OH) reacts with the hydroxyl group (-OH) on the surface of rare earth oxide (e.g. La2O3, CeO3, Nd2O3, etc.), such as through dehydration condensation to form stable siloxane bond (Si-O-Si) and silicon-rare earth (e.g. Si-O-La) bond;

[0022] For example: RSi(OH)3 + La2O3 → [RSiO] n -La-O-La-Si[OR'] 3-n +nH2O

[0023] Here, [RSiO] n represents the siloxane segment connected to the rare earth oxide, and n represents the degree of polymerization of the siloxane chain.

[0024] 3. Further reaction and crosslinking

[0025] The silane coupling agent has a functional group (e.g. methacryloxy) that can react with the high molecular material. In the subsequent processing process, this functional group will react with the corresponding functional group (e.g. double bond in the resin) on the high molecular chain to form chemical crosslinking, further strengthening the combination of rare earth oxide and high molecular matrix;

[0026] For example: RSi(OCH2CH=C(R"))2 + CH2=CH-COOH → RSi(CH2CHC(R")=CHCOO)2 + H2O

[0027] In this way, a continuous chemical network structure is formed, which tightly fixes the rare earth oxide inside the high molecular material (resin containing double bonds), greatly improving the performance of the composite material.

[0028] When the main etching agent flows to contact the etching-resistant layer of the circuit side wall of the circuit board, the rare earth oxide in the main etching agent reacts with the coupling agent and the resin containing double bonds in the etching-resistant layer under the action of the crosslinking agent (glycol dimethyl ether) and the acid condition, so that a new chemical grid structure is formed in the resin, and a high-strength and high-etching-resistant etching-resistant layer is formed, which can effectively protect the circuit side wall compared with the existing etching-resistant layer; the etching-resistant agent in the prior art can only slow down the etching speed and cannot completely resist etching, and the circuit side wall will still be partially etched. The etching-resistant layer of the present application can ensure efficient etching while greatly improving the etching resistance of the circuit side wall, and the circuit side wall will not be etched at all.

[0029] The present application changes the composition of the etching-resistant agent, and the resin containing double bonds is used as the main component, and glycol dimethyl ether is added. The glycol dimethyl ether can act as a crosslinking agent for the reaction between the resin containing double bonds and the rare earth oxide and the coupling agent, and can effectively improve the curing speed of the resin containing double bonds. The resin containing double bonds can be a methyl acryloyl-oxy modified polyurethane resin or a methyl methacrylate resin or a butyl methacrylate resin.

[0030] Further, the coupling agent is one of gamma-methacryloyloxypropyl trimethoxysilane, pyrophosphate, and phosphoric acid monoester.

[0031] The gamma-methacryloyloxypropyl trimethoxysilane, pyrophosphate, and phosphoric acid monoester have low reaction difficulty with the rare earth oxide and can react under acidic conditions.

[0032] Further, the rare earth oxide is at least one of La2O3, CeO2, and Nd2O3.

[0033] La2O3, CeO2, and Nd2O3 can react with the above-mentioned coupling agent and the resin containing double bonds under acidic conditions, and the reaction product has the effect of strengthening etching resistance.

[0034] The developing and etching process for producing the PCB board further comprises the following steps:

[0035] S4, when the etching amount of the main etching agent reaches 80% of the copper layer on the surface of the PCB board, a post-etching agent is used to replace the main etching agent to perform post-etching on the copper layer on the surface of the PCB board;

[0036] S5, after the post-etching, the PCB board is cleaned and dried to complete the developing and etching of the PCB board.

[0037] The post-etching agent comprises the following components in weight percentage: 20-30 parts of hydrochloric acid, 20-30 parts of organic acid, 3-5 parts of surfactant, and 1-3 parts of pH adjuster.

[0038] The present application adopts a post-etching agent to replace the main etching agent to etch the circuit board after main etching, so as to realize step-by-step etching, which is not step-by-step etching lines, but different etching strength and speed of the etching agent; the etching strength and speed of the post-etching agent are smaller than those of the main etching agent, which is suitable for fine etching in the later stage, and is helpful to control the etching degree and effect of the circuit board, so as to avoid over-etching.

[0039] Further, the coupling agent in the pre-etching agent is gamma-methacryloxypropyl trimethoxysilane; and the rare earth oxide in the main etching agent is La2O3.

[0040] Gamma-methacryloxypropyl trimethoxysilane has the best reaction effect with La2O3.

[0041] Further, the pre-etching agent comprises the following components in parts by weight: 40 parts of citric acid, 8 parts of EDTA, 5 parts of non-ionic or anionic surfactant, and 3 parts of coupling agent.

[0042] The main etching agent comprises the following components in parts by weight: 50 parts of ferric chloride, 15 parts of maleic acid, 15 parts of amino acid, 5 parts of hydrogen peroxide, 3 parts of pH regulator, and 2 parts of rare earth oxide.

[0043] The above components are the most suitable ratio of the present application.

[0044] Further, the organic acid in the post-etching agent is succinic acid, the surfactant is sodium lauryl ether sulfate, and the pH regulator is sodium hydroxide or tartaric acid.

[0045] The etching speed of succinic acid and sodium lauryl ether sulfate meets the actual demand of the later etching speed.

[0046] Further, the post-etching agent comprises the following components in parts by weight: 25 parts of hydrochloric acid, 25 parts of organic acid, 4 parts of surfactant, and 1-3 parts of pH regulator.

[0047] The developing and etching process for producing the PCB comprises the following specific steps:

[0048] S1, pre-etching the PCB with a pre-etching agent:

[0049] S1.1, rinsing the PCB to remove oil and dirt;

[0050] S1.2, configuring the pre-etching agent, spraying the pre-etching agent on the PCB uniformly at room temperature by using an atomizing nozzle, and retaining the pre-etching agent on the PCB, so that the circuit side wall of the PCB is paved with the pre-etching agent;

[0051] S2, after pre-etching, the circuit side wall of the PCB is subjected to anti-etching treatment with an etching resist: after the pre-etching agent stays on the PCB for 5 minutes, the etching resist is evenly coated on the circuit side wall of the PCB, and then the etching resist on the circuit side wall of the PCB is heated at 50-60 DEG C for 2-3 minutes, and then cooled at 10 DEG C for 5 minutes, to obtain a semi-cured etching resist layer, and the anti-etching treatment is completed;

[0052] S3, after the anti-etching treatment, the PCB after pre-etching is subjected to etching with a main etching agent: the main etching agent is prepared, and the main etching agent is sprayed vertically and evenly on the copper layer of the PCB at room temperature through a spray head, and after the spraying is continued for 10 minutes, the temperature of the environment where the PCB is located is increased to 60-70 DEG C, and the main etching agent on the copper layer of the PCB continuously etches the copper layer, and the rare earth oxide in the main etching agent flowing to the circuit side wall of the PCB reacts with the coupling agent and the resin containing double bonds on the circuit side wall of the PCB under the action of the crosslinking agent to form a high-strength network structure;

[0053] S4, when the etching amount of the main etching agent reaches 80% of the copper layer on the surface of the PCB, the main etching agent on the PCB is cleaned, and a post-etching agent is used instead of the main etching agent, and the post-etching agent is evenly sprayed on the PCB to post-etch the copper layer on the surface of the PCB;

[0054] S5, after the post-etching, the PCB is cleaned and dried to complete the development etching of the PCB.

[0055] The present application replaces the existing immersion etching method with a spraying method, thereby reducing the risk of side etching of the circuit board.

[0056] Further, the pH value of the main etching agent is 2, and the pH value of the post-etching agent is 4.

[0057] The stronger the acidity, the stronger the etching ability, and therefore, the acidity of the main etching agent and the post-etching agent is limited.

[0058] In summary, due to the adoption of the above technical solutions, the present application has the following advantages:

[0059] 1. A development etching process for producing a PCB utilizes rare earth oxide to generate a high-etching-resistance three-dimensional network structure with a coupling agent and a resin under the action of an acid and a crosslinking agent, thereby ensuring fast copper layer etching at a high speed and avoiding side etching, and solving the problem of etching of the circuit side wall of the circuit board.

[0060] 2. The present application replaces the existing immersion etching method with a spraying method, thereby reducing the risk of side etching of the circuit board.

[0061] 3. The application adopts a post-etching agent to replace the main etching agent to etch the circuit board after main etching, realizes step-by-step etching, helps to control the etching precision and etching effect of the circuit board, and avoids over-etching. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the present application clearer, the following embodiments are used to further describe the present application. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application, that is, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments.

[0063] Therefore, the detailed description of the embodiments of the present application below is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0064] It should be noted that the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the element defined by the statement "including a" does not exclude the presence of additional identical elements in the process, method, article or equipment including the element.

[0065] The features and performances of the present application will be further described in detail below in combination with embodiments.

[0066] Embodiment 1

[0067] The developing etching process for producing a PCB board provided by the preferred embodiment of the present application comprises the following steps:

[0068] S1, using a pre-etching agent to pre-etch the PCB board:

[0069] S1.1, rinsing the PCB to remove oil and dirt;

[0070] S1.2, configuring a pre-etching agent, at room temperature, using an atomizing nozzle to uniformly spray the pre-etching agent on the PCB board, the spraying pressure is 1.5Mp, the pre-etching agent is retained on the PCB board, and the pre-etching agent is laid on the sidewall of the circuit of the PCB board;

[0071] S2, after pre-etching, the circuit sidewall of the PCB is subjected to resist treatment by using a resist: after the pre-etching agent stays on the PCB for 5 minutes, the resist is evenly coated on the circuit sidewall of the PCB, and then the resist on the circuit sidewall of the PCB is heated at 50-60℃ for 2-3 minutes, and then cooled at 10℃ for 5 minutes, to obtain a semi-cured resist layer, and the resist treatment is completed;

[0072] S3, after the resist treatment, the PCB after pre-etching is subjected to etching by using a main etching agent: the main etching agent is configured, and the main etching agent is vertically and evenly sprayed on the copper layer of the PCB at normal temperature by using a spray head, the spraying pressure is 1.5 MPa, and the spraying is continuously performed for 10 minutes, then the temperature of the environment where the PCB is located is increased to 60-70℃, the main etching agent on the copper layer of the PCB continuously etches the copper layer, and the rare earth oxide in the main etching agent flowing to the circuit sidewall of the PCB reacts with the coupling agent and the resin containing double bonds on the circuit sidewall of the PCB to form a high-strength network structure under the action of the crosslinking agent;

[0073] S4, when the etching amount of the main etching agent reaches 80% of the copper layer on the surface of the PCB, the main etching agent on the PCB is cleaned, and a post-etching agent is used instead of the main etching agent, and the post-etching agent is evenly sprayed on the PCB to post-etch the copper layer on the surface of the PCB;

[0074] S5, after the post-etching, the PCB is cleaned and dried to complete the development etching of the PCB.

[0075] The pre-etching agent comprises the following components in parts by weight: 40 parts of citric acid, 8 parts of EDTA, 5 parts of a non-ionic or anionic surfactant, and 3 parts of a coupling agent.

[0076] The main etching agent comprises the following components in parts by weight: 50 parts of ferric chloride, 15 parts of maleic acid, 15 parts of an amino acid, 5 parts of hydrogen peroxide, 3 parts of a pH adjuster, and 2 parts of a rare earth oxide.

[0077] The resist is a resin containing double bonds and ethylene glycol dimethyl ether, and the mass ratio of ethylene glycol dimethyl ether to the resin containing double bonds is 1:10.

[0078] The coupling agent in the pre-etching agent is γ-methacryloyloxypropyl trimethoxysilane, and the rare earth oxide in the main etching agent is La2O3.

[0079] The post-etching agent comprises the following components in parts by weight: 25 parts of hydrochloric acid, 25 parts of succinic acid, 4 parts of sodium lauryl ether sulfate, and 1-3 parts of a pH adjuster, which is sodium hydroxide or tartaric acid.

[0080] The pH value of the main etching agent is 2, and the pH value of the post etching agent is 4.

[0081] Example 2

[0082] This example is based on example 1, and is different from example 1 in that the pre-etching agent comprises the following components in parts by weight: 30 parts of citric acid, 5 parts of EDTA, 3 parts of non-ionic or anionic surfactant, and 1 part of coupling agent.

[0083] Example 3

[0084] This example is based on example 1, and is different from example 1 in that the pre-etching agent comprises the following components in parts by weight: 35 parts of citric acid, 6.5 parts of EDTA, 4 parts of non-ionic or anionic surfactant, and 2 parts of coupling agent.

[0085] Example 4

[0086] This example is based on example 1, and is different from example 1 in that the main etching agent comprises the following components in parts by weight: 40 parts of ferric chloride, 10 parts of maleic acid, 10 parts of amino acid, 3 parts of hydrogen peroxide, 1 part of pH adjuster, and 1 part of rare earth oxide.

[0087] Example 5

[0088] This example is based on example 1, and is different from example 1 in that the main etching agent comprises the following components in parts by weight: 45 parts of ferric chloride, 12.5 parts of maleic acid, 12.5 parts of amino acid, 4 parts of hydrogen peroxide, 2 parts of pH adjuster, and 1.5 parts of rare earth oxide.

[0089] Example 6

[0090] This example is based on example 1, and is different from example 1 in that the post etching agent comprises the following components in parts by weight: 20 parts of hydrochloric acid, 20 parts of organic acid, 3 parts of surfactant, and 1 part of pH adjuster.

[0091] Example 7

[0092] This example is based on example 1, and is different from example 1 in that the post etching agent comprises the following components in parts by weight: 30 parts of hydrochloric acid, 30 parts of organic acid, 5 parts of surfactant, and 3 parts of pH adjuster.

[0093] Example 8

[0094] This example is based on example 1, and is different from example 1 in that the coupling agent is pyrophosphate.

[0095] Example 9

[0096] This example is based on example 1, except that the coupling agent is a phosphoric acid monoester.

[0097] Example 10

[0098] This example is based on example 1, except that the rare earth oxide is CeO2.

[0099] Example 11

[0100] This example is based on example 1, except that the rare earth oxide is Nd2O3.

[0101] Comparative Example 1

[0102] This comparative example is different from example 1 in that no rare earth oxide is added.

[0103] Comparative Example 2

[0104] This comparative example is different from example 1 in that no coupling agent is added.

[0105] Comparative Example 3

[0106] This comparative example is different from example 1 in that the mass ratio of ethylene glycol dimethyl ether to the resin containing double bonds is 1:11.

[0107] Comparative Example 4

[0108] This comparative example is different from example 1 in that the mass ratio of ethylene glycol dimethyl ether to the resin containing double bonds is 1:9.

[0109] Comparative Example 5

[0110] This comparative example is different from example 1 in that the pre-etching agent comprises the following components in parts by weight: 45 parts of citric acid, 13 parts of EDTA, 10 parts of a non-ionic or anionic surfactant, and 5 parts of a coupling agent.

[0111] Comparative Example 6

[0112] This comparative example is different from example 1 in that the main etching agent comprises the following components in parts by weight: 55 parts of ferric chloride, 20 parts of maleic acid, 20 parts of an amino acid, 10 parts of hydrogen peroxide, 4 parts of a pH adjuster, and 4 parts of a rare earth oxide.

[0113] Comparative Example 7

[0114] This comparative example is different from example 1 in that the pH value of the main etching agent is 3 and the pH value of the post-etching agent is 5.

[0115] Comparative Example 8

[0116] The difference between this comparative example and Example 1 is that the pH value of the main etchant is 1 and the pH value of the post-etching agent is 3.

[0117] Comparative Example 9

[0118] The difference between this comparative example and Example 1 is that the resin in the resist is a saturated resin, such as isophthalic acid-phthalic anhydride resin.

[0119] Test Example 1

[0120] The etching speed of the main etchant and the post-etching agent on the copper layer of the PCB circuit board in all the above examples and comparative examples is measured respectively. The detection method is as follows: a standard copper-clad plate (for example, FR-4 material) is selected, a 1.00 mm thick copper foil is uniformly coated on the surface of the copper-clad plate, a rectangular or circular pattern with a certain size and known area is made on the copper foil using photolithography technology, and the unexposed part of the resist is removed by development to expose the copper area to be etched. The etchant to be tested is arranged, the etchant is uniformly sprayed on the copper area to be etched by using a spray head, the spraying pressure is 1.5 MPa, and the sample is taken out after 10 minutes of continuous spraying. The etching solution is removed by rapid water washing to ensure that the copper layer is not continuously etched. A precise thickness measuring device such as a step meter, an X-ray fluorescence spectrometer (XRF), a scanning electron microscope (SEM) and a thickness measuring software, or a special copper foil thickness measuring tool is used to measure the remaining thickness of the copper foil after etching corresponding to the main etchant and the post-etching agent. The initial thickness is subtracted from the remaining thickness to obtain the etched thickness, and then the etched thickness difference is divided by 10 to obtain the etching speed in this period of time, which is in units of microns per minute. The results are shown in Table 1.

[0121] Table 1: Etching speed detection results

[0122]

[0123]

[0124] As can be seen from the data in Table 1, the coupling agent, the rare earth oxide and the ratio of each component will affect the etching speed of the main etchant. The etching speed of the main etchant is best at 21-22 microns per minute. If the etching speed is too fast, the etching degree will be uncontrollable and excessive etching will easily occur. If the etching speed is too slow, the etching efficiency will be affected. However, in the post-etching process, the etching speed is best controlled at about 14.5-15.5. If the post-etching speed is too fast, excessive etching will easily occur. Similarly, if the post-etching speed is too slow, the overall etching efficiency will be too low.

[0125] Test Example 2

[0126] The etching resistance of the resist layer in Examples 1-11 and Comparative Examples 1-9 was measured by the following method: a copper plate with a thickness of 1 mm was obtained, the resist was uniformly coated on the surface of the copper plate to form a 1 mm thick etching resist layer, the semi-cured etching resist layer was placed in an etching tank containing the corresponding main etchant, the copper plate was taken out after 10 minutes, the remaining thickness of the copper plate was measured, the etching thickness was obtained by subtracting the remaining thickness from the initial thickness, the etching rate was calculated by the etching thickness / initial thickness*100%, the etching resistance was determined by the etching rate, the lower the etching rate, the higher the etching resistance, and the stronger the etching resistance. The results are shown in Table 2.

[0127] Test Example 3

[0128] The line precision of the circuit board after etching in Examples 1-11 and Comparative Examples 1-9 was detected by the following method: an optical detection device (such as AOI, Automatic Optical Inspection) was used to check whether the line had bridging, open circuit or short circuit phenomenon, the use method of the optical detection device was prior art, and will not be explained here. The results are shown in Table 2.

[0129] Test Example 4

[0130] The circuit board after etching in Examples 1-11 and Comparative Examples 1-9 was subjected to metallographic detection, the surface quality of the etched copper layer was observed by a microscope, whether there were burrs and crack defects. The results are shown in Table 2.

[0131] Test Example 5

[0132] The circuit board containing a microprocessor was etched, and the circuit board after etching in Examples 1-11 and Comparative Examples 1-9 was subjected to power-on test to see whether the system could start normally. The results are shown in Table 2.

[0133] Table 2 Test Results

[0134] Etching rate of resist layer Line precision detection Metallographic detection Power-on test Example 1 0 No bridging, open or short circuit phenomenon No burr, no crack Normal Example 2 0.02％ No bridging, open or short circuit phenomenon No burr, no crack Normal Example 3 0.01％ No bridging, open or short circuit phenomenon No burr, no crack Normal Example 4 0.01％ No bridging, open or short circuit phenomenon No burr, no crack Normal Example 5 0 No bridging, open or short circuit phenomenon No burr, no crack Normal Example 6 0 No bridging, open or short circuit phenomenon No burr, no crack Normal Example 7 0 No bridging, open or short circuit phenomenon No burr, no crack Normal Example 8 0.01％ No bridging, open or short circuit phenomenon No burr, no crack Normal Example 9 0.02％ No bridging, open or short circuit phenomenon No burr, no crack Normal Example 10 0 No bridging, open or short circuit phenomenon No burr, no crack Normal Example 11 0 No bridging, open or short circuit phenomenon No burr, no crack Normal Comparative Example 1 0.5％ No bridging, open or short circuit phenomenon Burr, no crack Normal Comparative Example 2 0.8％ No bridging, open or short circuit phenomenon No burr, crack Normal Comparative Example 3 0 No bridging, open or short circuit phenomenon No burr, no crack Normal Comparative Example 4 0.01％ No bridging, open or short circuit phenomenon No burr, no crack Normal Comparative Example 5 0 No bridging, open or short circuit phenomenon No burr, no crack Normal Comparative Example 6 0 No bridging, open or short circuit phenomenon No burr, no crack Normal Comparative Example 7 0 No bridging, open or short circuit phenomenon No burr, no crack Normal Comparative Example 8 0 No bridging, open or short circuit phenomenon No burr, no crack Normal Comparative Example 9 0.1％ No bridging, open or short circuit phenomenon Burr, no crack Normal

[0135] As shown in Table 2, the chemical reaction between the coupling agent, the rare earth oxide and the resin containing double bonds seriously affects the etching resistance of the etching resist layer, and all three are indispensable. The resist of the present application has strong etching resistance after reacting with the coupling agent and the rare earth oxide, and has good etching resistance to the line side wall of the circuit board.

[0136] In combination with the data in Table 1 and Table 2, and in combination with material consumption and cost, the best ratio is Example 1 of the present application, and the etching speed and etching resistance are both best.

[0137] The above merely describes the preferred embodiments of the present application and is not used to limit the protection scope of the present application, and any modification, equivalent replacement and improvement made by any person skilled in the art within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A process for developing and etching a PCB board, characterized by: It comprises the following steps: S1, using a pre-etching agent to pre-etch the PCB board: S1.1, rinse the PCB, remove oil and dirt; S1.2, configure the pre-etching agent, at room temperature, use the atomizing nozzle to uniformly spray the pre-etching agent on the PCB board, the spraying pressure is 1.5Mp, the pre-etching agent is retained on the PCB board, and the pre-etching agent is laid on the sidewall of the circuit of the PCB board; S2, after pre-etching, the sidewall of the circuit of the PCB board is treated with an etching resist: after the pre-etching agent is retained on the PCB board for 5 minutes, the etching resist is uniformly coated on the sidewall of the circuit of the PCB board, then the etching resist on the sidewall of the circuit of the PCB board is heated at 50-60℃ for 2-3 minutes, and after heating, the etching resist on the sidewall of the circuit of the PCB board is cooled at 10℃ for 5 minutes, to obtain a semi-cured etching resist layer, and the etching treatment is completed; S3, after the etching treatment, the PCB board pre-etched by the pre-etching agent is etched by using a main etching agent: the main etching agent is configured, and the main etching agent is vertically and uniformly sprayed on the copper layer of the PCB board by using a nozzle at room temperature, the spraying pressure is 1.5Mp, and after spraying for 10 minutes, the temperature of the environment where the PCB board is located is increased to 60-70℃, the main etching agent on the copper layer of the PCB board continuously etches the copper layer, the rare earth oxide in the main etching agent flowing to the sidewall of the circuit of the PCB board is mixed with the coupling agent and the resin containing double bonds on the sidewall of the circuit of the PCB board, and reacts under the action of the crosslinking agent to form a high-strength network structure; The pre-etching agent comprises the following components in parts by weight: 30-40 parts of citric acid, 5-8 parts of EDTA, 3-5 parts of non-ionic or anionic surfactant, and 1-3 parts of coupling agent; The main etching agent comprises the following components in parts by weight: 40-50 parts of ferric chloride, 10-15 parts of maleic acid, 10-15 parts of amino acid, 3-5 parts of hydrogen peroxide, 1-3 parts of pH adjuster, and 1-2 parts of rare earth oxide; the pH value of the main etching agent is 2; The etching resist is a resin containing double bonds and ethylene glycol dimethyl ether, and the mass ratio of ethylene glycol dimethyl ether to the resin containing double bonds is 1:

10.

2. A process for developing and etching a PCB board as claimed in claim 1, wherein: The coupling agent is one of gamma-methacryloxypropyl trimethoxysilane, pyrophosphate, and phosphoric monoester.

3. A process for developing and etching a PCB board as claimed in claim 2, wherein: The rare earth oxide is at least one of La2O3, CeO2, and Nd2O3.

4. The process for developing and etching a PCB as claimed in claim 1, wherein: It further comprises the following steps: S4, when the etching amount of the main etching agent reaches 80% of the copper layer on the surface of the PCB board, a post-etching agent is used to replace the main etching agent to post-etch the copper layer on the surface of the PCB board; S5, after the post-etching, the PCB board is cleaned and dried to complete the development etching of the PCB board; The post-etching agent comprises the following components in parts by weight: 20-30 parts of hydrochloric acid, 20-30 parts of organic acid, 3-5 parts of surfactant, and 1-3 parts of pH adjuster.

5. The process of claim 3, wherein: The coupling agent in the pre-etching agent is gamma-methacryloxypropyl trimethoxysilane; and the rare earth oxide in the main etching agent is La2O3.

6. A process for developing and etching a PCB board as claimed in claim 5 wherein: The pre-etching agent comprises the following components in parts by weight: 40 parts of citric acid, 8 parts of EDTA, 5 parts of non-ionic or anionic surfactant, and 3 parts of coupling agent; The main etching agent comprises the following components in parts by weight: 50 parts of ferric chloride, 15 parts of maleic acid, 15 parts of amino acid, 5 parts of hydrogen peroxide, 3 parts of pH regulator, and 2 parts of rare earth oxide.

7. The process of claim 4, wherein the process is characterized by: The organic acid in the post-etching agent is succinic acid, the surfactant is sodium lauryl ether sulfate, and the pH regulator is sodium hydroxide or tartaric acid.

8. A process for developing and etching a PCB board as claimed in claim 7, wherein: The post-etching agent comprises the following components in parts by weight: 25 parts of hydrochloric acid, 25 parts of organic acid, 4 parts of surfactant, and 1-3 parts of pH regulator.

9. The process of claim 4, wherein: The method comprises the following specific steps: S1, pre-etching the PCB board with a pre-etching agent; S1.1, rinsing the PCB to remove oil and dirt; S1.2, preparing the pre-etching agent, and spraying the pre-etching agent on the PCB board at room temperature by using a spraying nozzle under a spraying pressure of 1.5 MPa, so that the pre-etching agent is uniformly sprayed on the PCB board and deposited on the sidewalls of the circuit of the PCB board; S2, after the pre-etching, performing an etching-resistant treatment on the sidewalls of the circuit of the PCB board by using an etching-resistant agent: after the pre-etching agent is deposited on the PCB board for 5 minutes, the etching-resistant agent is uniformly coated on the sidewalls of the circuit of the PCB board, and then the etching-resistant agent on the sidewalls of the circuit of the PCB board is heated at 50-60 DEG C for 2-3 minutes, and then cooled at 10 DEG C for 5 minutes to obtain a semi-cured etching-resistant layer, thereby completing the etching-resistant treatment; S3, after the etching-resistant treatment, etching the PCB board after the pre-etching by using a main etching agent: preparing the main etching agent, and spraying the main etching agent on the copper layer of the PCB board vertically and uniformly at room temperature by using a nozzle under a spraying pressure of 1.5 MPa, and after the main etching agent is continuously sprayed on the copper layer of the PCB board for 10 minutes, the temperature of the environment where the PCB board is located is increased to 60-70 DEG C, the main etching agent on the copper layer of the PCB board continuously etches the copper layer, and the rare earth oxide in the main etching agent flowing to the sidewalls of the circuit of the PCB board reacts with the coupling agent and the resin containing double bonds on the sidewalls of the circuit of the PCB board under the action of the cross-linking agent to form a high-strength network structure; S4, after the etching amount of the main etching agent reaches 80% of the copper layer on the surface of the PCB board, the main etching agent on the PCB board is cleaned, a post-etching agent is used to replace the main etching agent, and the post-etching agent is uniformly sprayed on the PCB board to perform post-etching on the copper layer on the surface of the PCB board; S5, after the post-etching, the PCB board is cleaned and dried to complete the development etching of the PCB board.

10. The process of claim 9, wherein: The pH value of the main etching agent is 2, and the pH value of the post-etching agent is 4.

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