Process for improving solder resist bubbles of thick copper dense circuit board of new energy automobile and circuit board thereof

Abstract

The invention provides a process for improving solder resist bubbles of a thick copper dense circuit board of a new energy automobile and the circuit board. According to the technology for improving the solder resist bubbles of the thick copper dense circuit board of the new energy automobile, the modified solder resist ink with the particle size smaller than 300 microns and the viscosity ranging from 95 pda.s to 115 pda.s is adopted for conducting first face silk-screen operation on the thick copper dense circuit bare board; then carrying out first standing operation and first pre-drying operation in sequence to obtain a thick copper dense circuit board B; carrying out second surface screen printing operation on the thick copper dense circuit board B; and then carrying out second standing operation, second pre-drying operation, pre-baking operation and exposure and development operation in sequence. The process not only simplifies the solder resist process, but also improves the solder resist production efficiency, ensures that the appearance of the thick copper dense circuit board of the new energy automobile has no bubble defect, and improves the filling tightness of the modified solder resist ink layer in the corners of the thick copper dense circuit and the circuit spacing. Therefore, the corners of the thick copper dense lines and the spacing of the thick copper dense lines are well protected.

Description

Technical Field

[0001] The present disclosure relates to the technical field of new energy vehicle circuit boards, and in particular to a process for improving solder mask bubbles in thick copper dense circuit boards for new energy vehicles and a circuit board thereof. Background Art

[0002] The thick copper dense circuit board of new energy vehicles uses thicker copper foil (usually more than 1.5OZ or 53μm) as the conductive layer to form denser lines on the conductive layer to better meet the high current transmission needs of new energy vehicles.

[0003] However, due to the large height difference between the copper surface and the substrate surface of the thick copper dense circuit board of new energy vehicles, and the narrow gap between the circuits, it is easy to have many pinhole bubbles, ink failure and bubbles between dense circuits in the solder mask screen printing process, as disclosed in PCT / CN2019 / 087760, a method for preparing a thick copper printed circuit board without pores using a modified solder mask ink and a printed circuit board thereof.

[0004] However, the above-mentioned method for making a thick copper printed circuit board without pores using modified solder resist ink solves the problems of many pinhole bubbles, ink failure, and bubbles easily generated between dense circuits in thick copper dense circuit boards by printing once with the first modified solder resist ink and printing twice with the second solder resist oil, but there is a problem of complicated operation. In addition, from the content of paragraph

[0005] of the specification of the above-mentioned method for making a thick copper printed circuit board without pores using modified solder resist ink, it can be seen that since the first modified solder resist ink uses matte color ink as the liquid photoresist ink, the ink characteristic particles are large, although it is conducive to the volatilization of bubbles in the modified solder resist ink, the larger particles will cause cavitation bubbles inside the modified solder resist ink layer that is subsequently cured at high temperature, causing the board surface of the thick copper dense circuit board of new energy vehicles to be easily concave and uneven in appearance. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for solving the problems of many pinhole bubbles, ink failure and easy generation of bubbles between dense circuits of thick copper dense circuit boards for new energy vehicles by only one printing. The method not only simplifies the solder mask process flow, but also improves the solder mask production efficiency, and ensures that the first solder mask ink layer and the second solder mask ink layer prepared subsequently have no hole defects inside and outside, and improves the flatness and uniformity of the first solder mask ink layer and the second solder mask ink layer, and ensures that the connection reliability of the first solder mask ink layer and the second solder mask ink layer with the thick copper dense circuit bare board is good, and ensures that there is no ink leakage and misalignment at the edges of the first solder mask ink layer and the second solder mask ink layer, and ensures that the circuit pattern of the thick copper dense circuit bare board is clear, readable and accurate, and is particularly suitable for the thick copper dense circuit bare board with a bottom copper layer thickness of ≥1.5OZ, and the circuit spacing of the thick copper dense circuit bare board is 80um~300um. The improved solder mask bubble process of the thick copper dense circuit board for new energy vehicles and the circuit board thereof.

[0006] The purpose of this disclosure is achieved through the following technical solutions:

[0007] A process for improving solder mask bubbles on thick copper dense circuit boards for new energy vehicles.

[0008] Get thick copper dense circuit bare board;

[0009] The first side of the thick copper dense circuit bare board is screen printed with modified solder resist ink to obtain a thick copper dense circuit board A; wherein the particle size of the modified solder resist ink is less than 300 um, and the viscosity of the modified solder resist ink is 95 pda.s to 115 pda.s;

[0010] Performing a first static operation on the thick copper dense circuit board A;

[0011] Performing a first pre-drying operation on the thick copper dense circuit board A after the first static operation to obtain a thick copper dense circuit board B;

[0012] The modified solder resist ink is used to perform a second-side screen printing operation on the thick copper dense circuit board B to obtain a thick copper dense circuit board C;

[0013] Performing a second static operation on the thick copper dense circuit board C;

[0014] Performing a second pre-drying operation on the thick copper dense circuit board C after the second static operation to obtain a thick copper dense circuit board D;

[0015] Pre-baking the thick copper dense circuit board D to obtain a thick copper dense circuit board E;

[0016] The thick copper dense circuit board E is sequentially subjected to exposure operation and development operation to obtain the thick copper dense circuit board for new energy vehicles.

[0017] In one embodiment, the preparation of the modified solder resist ink comprises the following steps:

[0018] The barium sulfate, epoxy resin, acrylate, amine compound and diethylene glycol ethyl ether acetate are stirred and mixed to obtain an ink mixture; wherein the stirring speed is: 1000r / d to 1500r / d; the stirring time is 12min to 20min;

[0019] Performing a vacuum operation on the ink mixture;

[0020] The ink mixture that has undergone the vacuuming operation is subjected to a third static operation to obtain the modified solder resist ink.

[0021] In one embodiment, the vacuuming operation time is 5 min to 10 min, and the vacuuming operation pressure is -300 Mpa to -200 Mpa; and / or,

[0022] The time of the third standing operation is 20 minutes to 30 minutes.

[0023] In one embodiment, the printing speed of the first screen printing operation is 200 mm / s to 300 mm / s; the pressure of the screen printing scraper is 0.4 Mpa to 0.6 Mpa; and / or,

[0024] The printing speed of the second-side screen printing operation is 200 mm / s to 300 mm / s.

[0025] In one embodiment, the first standing operation time is 0.5h to 2h.

[0026] In one embodiment, the second standing operation time is 0.5h to 2h.

[0027] In one of the embodiments, the thickness of the bottom copper layer of the thick copper dense circuit bare board is ≥1.5OZ, and the circuit spacing of the thick copper dense circuit bare board is 80um-300um.

[0028] In one embodiment, the first static operation includes the following specific steps: when the thick copper dense circuit board A is placed flat on the hollow static rack, the silk screen surface of the thick copper dense circuit board A is kept downward; and / or,

[0029] The second static operation includes the following specific steps: when the thick copper dense circuit board C is placed flat on the hollow static rack, the silk screen surface of the thick copper dense circuit board C is kept downward.

[0030] In one embodiment, the first pre-drying temperature is 73° C. to 75° C., and the first pre-drying time is 20 min to 30 min.

[0031] A thick copper dense circuit board for new energy vehicles is prepared by using the process for improving solder resist bubbles in thick copper dense circuit boards for new energy vehicles in any of the above embodiments.

[0032] Compared with the prior art, the present invention has at least the following advantages:

[0033] 1) By controlling the particle size of the modified solder resist ink to be less than 300um and the viscosity of the modified solder resist ink to be 95pda.s-115pda.s, the modified solder resist ink has good fluidity and the particle size of the modified solder resist ink is small, which effectively avoids the problem of the ink not being able to oil, and at the same time, in conjunction with the first static operation and the second static operation, effectively reduces the problem of large particles in the modified solder resist ink causing the subsequent high-temperature cured modified solder resist ink layer to have cavities and bubbles inside, resulting in poor appearance of depressions and unevenness; and, the modified solder resist ink with a smaller particle size can be better filled in the spacing of the thick copper dense circuit, effectively avoiding the modified solder resist ink filling at the corners of the thick copper dense circuit. There are small gaps, which causes the modified solder resist ink layer to be unable to achieve good protection of the corners of the thick copper dense circuit and the spacing of the thick copper dense circuit, that is, in the present disclosure, by controlling the particle size of the modified solder resist ink to be less than 300um When the viscosity of the modified solder resist ink is 95pda.s~115pda.s, on the premise of solving the problem of ink not oiling, the compactness of the modified solder resist ink layer in the corners of thick copper dense circuits and the circuit spacing is improved, which not only realizes the reliable and firm connection between the modified solder resist ink and the corners of thick copper dense circuits and the spacing of thick copper dense circuits, but also realizes better protection of the corners of thick copper dense circuits and the spacing of thick copper dense circuits, and can effectively reduce the probability of hole defects in the first solder resist ink layer and the second solder resist ink layer finally formed; it also reduces the problem of poor appearance of depression and unevenness caused by the presence of a large number of large particles in the subsequent high-temperature cured modified solder resist ink layer, which is particularly suitable for applications where the thickness of the bottom copper layer of the thick copper dense circuit bare board is ≥1.5OZ, and the circuit spacing of the thick copper dense circuit bare board is 80um~300um.

[0034] 2) Compared with the traditional secondary printing, the present invention improves the particle size and viscosity of the modified solder resist ink, and can solve the problems of many pinhole bubbles, ink failure and easy generation of bubbles between dense circuits in the thick copper dense circuit boards of new energy vehicles with only one printing. It not only simplifies the solder resist process, but also improves the solder resist production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 The present invention is a flow chart of a process for improving solder mask bubbles in thick copper dense circuit boards for new energy vehicles according to an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to facilitate the understanding of the present disclosure, the present disclosure will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present disclosure are given in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present disclosure more thoroughly and comprehensively understood.

[0038] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present disclosure. The terms used herein in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0040] The present invention provides a process for improving solder mask bubbles in thick copper dense circuit boards of new energy vehicles, comprising obtaining a thick copper dense circuit bare board; performing a first screen printing operation on the thick copper dense circuit bare board using a modified solder mask ink to obtain a thick copper dense circuit board A; wherein the particle size of the modified solder mask ink is less than 300um, and the viscosity of the modified solder mask ink is 95pda.s to 115pda.s; performing a first static operation on the thick copper dense circuit board A; performing a first pre-drying operation on the thick copper dense circuit board A after the first static operation, to obtain to a thick copper dense circuit board B; use the modified solder resist ink to perform a second screen printing operation on the thick copper dense circuit board B to obtain a thick copper dense circuit board C; perform a second static operation on the thick copper dense circuit board C; perform a second pre-drying operation on the thick copper dense circuit board C after the second static operation to obtain a thick copper dense circuit board D; perform a pre-bake operation on the thick copper dense circuit board D to obtain a thick copper dense circuit board E; perform an exposure operation and a development operation on the thick copper dense circuit board E in sequence to obtain the thick copper dense circuit board for new energy vehicles.

[0041] The above-mentioned process for improving solder mask bubbles in thick copper dense circuit boards of new energy vehicles controls the particle size of the modified solder mask ink to be less than 300um and the viscosity of the modified solder mask ink to be 95pda.s~115pda.s, so that the modified solder mask ink has good fluidity and the particle size of the modified solder mask ink is small, which effectively avoids the problem of ink not being able to oil down, and at the same time cooperates with the first static operation and the second static operation, effectively reduces the problem of large particles in the modified solder mask ink causing the subsequent high-temperature cured modified solder mask ink layer to have voids and bubbles inside, resulting in concave and uneven appearance; and, the modified solder mask ink with a smaller particle size can be better filled in the spacing of the thick copper dense circuit, effectively avoiding the modified solder mask ink at the corners of the thick copper dense circuit. Filling is not dense and there are tiny gaps, so that the modified solder mask ink layer cannot achieve good protection of the corners of the thick copper dense circuit and the spacing of the thick copper dense circuit, that is, in the present disclosure, by controlling the modified solder mask ink When the particle size of the ink is less than 300um and the viscosity of the modified solder resist ink is 95pda.s-115pda.s, on the premise of solving the problem of the ink not oiling, the compactness of the modified solder resist ink layer in the corners of the thick copper dense circuit and the circuit spacing is improved, which not only realizes the reliable and firm connection between the modified solder resist ink and the corners of the thick copper dense circuit and the thick copper dense circuit spacing, but also realizes better protection of the corners of the thick copper dense circuit and the thick copper dense circuit spacing, and can effectively reduce the probability of hole defects in the first solder resist ink layer and the second solder resist ink layer finally formed; it also reduces the problem of poor appearance caused by concave and uneven appearance caused by the presence of a large number of large particles in the modified solder resist ink layer cured at high temperature, and is particularly suitable for the thick copper dense circuit bare board with a bottom copper layer thickness of ≥1.5OZ, and the thick copper dense circuit bare board with a circuit spacing of 80um-300um. Furthermore, compared with traditional secondary printing, the present invention improves the particle size and viscosity of the modified solder resist ink, and can solve the problems of many pinhole bubbles, ink failure, and easy generation of bubbles between dense circuits in thick copper dense circuit boards of new energy vehicles with only one printing. This not only simplifies the solder resist process, but also improves the solder resist production efficiency.

[0042] See also Figure 1 In order to better understand the technical solution and beneficial effects of the present disclosure, the present disclosure is further described in detail in combination with specific embodiments. An embodiment of the process for improving solder mask bubbles in thick copper dense circuit boards for new energy vehicles includes some or all of the following steps:

[0043] S101. Obtain a bare board with thick copper dense circuits; a bare board with thick copper dense circuits refers to a board with a circuit diagram printed on a resin board. Specifically, in one embodiment, the thickness of the bottom copper layer of the bare board with thick copper dense circuits is ≥1.5OZ, and the circuit spacing of the bare board with thick copper dense circuits is 80um to 300um.

[0044] S102, using modified solder resist ink to perform a first-side silk screen printing operation on the thick copper dense circuit bare board to obtain a thick copper dense circuit board A; wherein the particle size of the modified solder resist ink is less than 300um, and the viscosity of the modified solder resist ink is 95pda.s to 115pda.s.

[0045] It should be noted that with the continuous development of thick copper dense circuit boards for new energy vehicles, the market has put forward higher requirements for thinness and lightness, which has forced new energy vehicle circuit board manufacturers to make further breakthroughs in the original design. This undoubtedly poses more severe challenges to new energy vehicle circuit board manufacturers, such as facing difficulties in printing circuits and silk-screen printing of solder mask ink layers. Among them, most of the current solder mask processes can only relatively well adapt to the application of circuit spacing of new energy vehicle circuit boards of 300um to 500um, as the patent literature involved in the background technology, but for circuit spacing below 300um, there are still problems such as many pinhole bubbles in thick copper dense circuit boards, ink failure, and bubbles easily generated between dense circuits.

[0046] Therefore, in order to solve the above-mentioned technical problems, in the present disclosure, the traditional solder resist ink is improved to ensure that the particle size of the modified solder resist ink is less than 300um and the viscosity of the modified solder resist ink is 95pda.s~115pda.s, so that the modified solder resist ink has good fluidity and the particle size of the modified solder resist ink is small, which effectively avoids the problem of ink not oiling. At the same time, in conjunction with the first static operation and the second static operation, the problem of large particles in the modified solder resist ink causing the subsequent high-temperature cured modified solder resist ink layer to have voids and bubbles inside, resulting in concave and uneven appearance is effectively reduced; and the modified solder resist ink with a smaller particle size can better fill in the spacing of thick copper dense circuits, effectively avoiding the modified solder resist ink filling at the corners of the thick copper dense circuit. There are tiny gaps, which causes the modified solder resist ink layer to be unable to achieve the corners of the thick copper dense circuit. Better protection of corners and thick copper dense circuit spacing, that is, in the present disclosure, by controlling the particle size of the modified solder resist ink to be less than 300um and the viscosity of the modified solder resist ink to be 95pda.s~115pda.s, on the premise of solving the problem of ink not oiling, the tightness of the modified solder resist ink layer in the corners of thick copper dense circuits and in the circuit spacing is also improved, which not only achieves the reliable and firm connection between the modified solder resist ink and the corners of thick copper dense circuits and the spacing of thick copper dense circuits, but also achieves better protection of the corners of thick copper dense circuits and the spacing of thick copper dense circuits, and can effectively reduce the probability of hole defects in the first solder resist ink layer and the second solder resist ink layer finally formed; it also reduces the problem of poor appearance of concave and uneven appearance caused by the presence of a large number of large particles in the modified solder resist ink layer that is subsequently cured at high temperature.

[0047] It can also be understood that the presence of more large particles in the conventional solder resist ink will increase the gap between the scraper at the edge of the first knife line and the first surface of the bare board with dense thick copper circuits, resulting in ink leakage or dislocation at the edge of the first solder resist ink layer. In addition, since the line spacing of the bare board with dense thick copper circuits is relatively small, if the particle size of the modified solder resist ink is larger, the modified solder resist ink cannot flow into the line spacing more comprehensively, resulting in more fine gaps in the line spacing, which not only leads to the problem of poor filling tightness of the modified solder resist ink, but also causes more holes in the modified solder resist ink to affect the quality of the solder resist ink. Therefore, in the present disclosure, by controlling the particle size of the modified solder resist ink to be less than 300um, not only the problem of poor appearance caused by the presence of more large particles in the modified solder resist ink during subsequent high-temperature curing is reduced, but also the filling tightness of the modified solder resist ink is improved, and the problem of more holes in the modified solder resist ink layer caused by more fine gaps when the modified solder resist ink is filled is effectively improved.

[0048] It can also be understood that the viscosity of the current traditional solder resist ink is usually 120pda.s, and the traditional solder resist ink contains more large particles, which will cause the solder resist ink to have poor fluidity, resulting in the solder resist ink being easily blocked during a long period of silk screen printing, and easily causing the first knife line edge to not be oiled during the silk screen printing process; if the viscosity of the modified solder resist ink is less than 95pda.s, the modified solder resist ink will be easy to flow during the silk screen printing process, resulting in uneven coating thickness of the modified solder resist ink, and the low viscosity modified solder resist ink will more easily penetrate into the tiny gaps of the thick copper dense circuit bare board, causing the modified solder resist ink to easily penetrate, causing the circuit pattern of the thick copper dense circuit bare board to become blurred, affecting the readability and accuracy of the thick copper dense circuit bare board.

[0049] Therefore, in the present disclosure, the viscosity of the modified solder resist ink is controlled to be 95pda.s~115pda.s to ensure that the viscosity of the modified solder resist ink is more appropriate, that is, to ensure that the modified solder resist ink has better fluidity on the bare board with thick copper dense circuits, and there will be no problem of no oil on the edge of the first knife line, and the uniformity of the coating thickness of the modified solder resist ink is ensured, and the problem of the modified solder resist ink penetrating and causing the circuit pattern of the bare board with thick copper dense circuits to become blurred is avoided. In particular, when the particle size of the modified solder resist ink is less than 300um, it not only solves the problem of ink leakage or dislocation at the edge of the first solder resist ink layer, thereby ensuring the printing quality of the edge of the first solder resist ink layer and the precise positioning of the first solder resist ink layer, but also reduces the subsequent high-temperature cured modified solder resist ink due to the presence of a large number of large particles, which leads to the formation of voids and bubbles inside the modified solder resist ink layer, resulting in depressions, The problem of uneven appearance is solved, and the filling tightness of the modified solder resist ink is improved, and the problem of many holes in the modified solder resist ink layer due to many small gaps when the modified solder resist ink is filled is effectively improved, that is, it is ensured that the first solder resist ink layer and the second solder resist ink layer prepared later have no hole defects inside and outside, and the flatness and uniformity of the first solder resist ink layer and the second solder resist ink layer are improved, and the connection reliability of the first solder resist ink layer and the second solder resist ink layer with the thick copper intensive circuit bare board is ensured to be good, and it is also ensured that there is no ink leakage and misalignment at the edges of the first solder resist ink layer and the second solder resist ink layer, and the circuit pattern of the thick copper intensive circuit bare board is clear, readable and accurate, and it is particularly suitable for applications where the thickness of the bottom copper layer of the thick copper intensive circuit bare board is ≥1.5OZ, and the circuit spacing of the thick copper intensive circuit bare board is 80um~300um.

[0050] In this embodiment, when the modified solder resist ink is used to perform the screen printing operation on the first side of the bare board with dense thick copper circuits, a first solder resist ink layer is formed on the first side of the bare board with dense thick copper circuits.

[0051] S103, performing a first static operation on the thick copper dense circuit board A. It can be understood that, since a small amount of bubbles still exist during the first screen printing operation, in the present disclosure, the first static operation is performed on the thick copper dense circuit board A to effectively remove the bubbles remaining in the first solder resist ink layer.

[0052] S104, performing a first pre-drying operation on the thick copper dense circuit board A after the first static operation to obtain a thick copper dense circuit board B, so that the first solder resist ink layer can be better initially formed and fixed on the first side of the thick copper dense circuit bare board, effectively avoiding the problem of the first solder resist ink layer falling off and severe wear during the subsequent second-side silk screen printing operation; and the first pre-drying operation can more comprehensively remove the bubbles in the first solder resist ink layer.

[0053] S105. Use the modified solder resist ink to perform a second-side silk-screen operation on the thick copper dense circuit board B to obtain a thick copper dense circuit board C. Use the same modified solder resist ink as the first-side silk-screen operation to perform a second-side silk-screen operation on the second side of the thick copper dense circuit board B to ensure that a second solder resist ink layer is formed on the second side of the thick copper dense circuit board B, which has no bubble defects in appearance and provides better protection for the corners of the thick copper dense circuits and the spacing between the thick copper dense circuits.

[0054] S106, performing a second static operation on the thick copper dense circuit board C. It can be understood that, since a small amount of bubbles still exist during the second-side screen printing operation, in the present disclosure, the thick copper dense circuit board C is subjected to a second static operation to effectively remove the bubbles remaining in the second solder mask ink layer.

[0055] S107, performing a second pre-drying operation on the thick copper dense circuit board C after the second static operation to obtain a thick copper dense circuit board D; so that the second solder resist ink layer can be better initially formed and fixed on the second surface of the thick copper dense circuit bare board, and the bubbles in the second solder resist ink layer can be more comprehensively removed through the second pre-drying operation.

[0056] S108, pre-baking the thick copper dense circuit board D to obtain a thick copper dense circuit board E; allowing the first solder resist ink layer and the second solder resist ink layer to be completely solidified on both sides of the thick copper dense circuit bare board, thereby ensuring the firmness of the connection between the first solder resist ink layer, the second solder resist ink layer and the bottom copper layer of the thick copper dense circuit bare board.

[0057] S109, performing exposure operation and development operation on the thick copper dense circuit board E in sequence to obtain the thick copper dense circuit board for new energy vehicles.

[0058] It can be understood that, first, the thick copper dense circuit board E is exposed to cause the photosensitive parts in the first solder resist ink layer and the second solder resist ink layer to undergo polymerization reaction, so as to form circuit patterns in the first solder resist ink layer and the second solder resist ink layer. Next, the thick copper dense circuit board E after the exposure operation is developed again, and the unexposed parts of the first solder resist ink layer and the second solder resist ink layer are cleaned with a developer, while the parts that undergo polymerization reaction after exposure are retained, so that the thick copper dense circuit board for new energy vehicles after development presents a clear circuit pattern, and ensures that the blocking areas of the first solder resist ink layer and the second solder resist ink layer are formed.

[0059] The above-mentioned process for improving solder mask bubbles in thick copper dense circuit boards of new energy vehicles controls the particle size of the modified solder mask ink to be less than 300um and the viscosity of the modified solder mask ink to be 95pda.s~115pda.s, so that the modified solder mask ink has good fluidity and the particle size of the modified solder mask ink is small, which effectively avoids the problem of ink not being able to oil down, and at the same time cooperates with the first static operation and the second static operation, effectively reduces the problem of large particles in the modified solder mask ink causing the subsequent high-temperature cured modified solder mask ink layer to have voids and bubbles inside, resulting in concave and uneven appearance; and, the modified solder mask ink with a smaller particle size can be better filled in the spacing of the thick copper dense circuit, effectively avoiding the modified solder mask ink at the corners of the thick copper dense circuit. Filling is not dense and there are tiny gaps, so that the modified solder mask ink layer cannot achieve good protection of the corners of the thick copper dense circuit and the spacing of the thick copper dense circuit, that is, in the present disclosure, by controlling the modified solder mask ink When the particle size of the ink is less than 300um and the viscosity of the modified solder resist ink is 95pda.s-115pda.s, on the premise of solving the problem of the ink not oiling, the compactness of the modified solder resist ink layer in the corners of the thick copper dense circuit and the circuit spacing is improved, which not only realizes the reliable and firm connection between the modified solder resist ink and the corners of the thick copper dense circuit and the thick copper dense circuit spacing, but also realizes better protection of the corners of the thick copper dense circuit and the thick copper dense circuit spacing, and can effectively reduce the probability of hole defects in the first solder resist ink layer and the second solder resist ink layer finally formed; it also reduces the problem of poor appearance caused by concave and uneven appearance caused by the presence of a large number of large particles in the modified solder resist ink layer cured at high temperature, and is particularly suitable for the thick copper dense circuit bare board with a bottom copper layer thickness of ≥1.5OZ, and the thick copper dense circuit bare board with a circuit spacing of 80um-300um.

[0060] Furthermore, compared with traditional secondary printing, the present invention improves the particle size and viscosity of the modified solder resist ink, and can solve the problems of many pinhole bubbles, ink failure, and easy generation of bubbles between dense circuits in thick copper dense circuit boards of new energy vehicles with only one printing. This not only simplifies the solder resist process, but also improves the solder resist production efficiency.

[0061] It is understandable that if the particle size of the modified solder resist ink is less than 80um, there will be a small probability of penetration, resulting in the problem that the circuit pattern of the bare board with thick copper dense circuit becomes blurred. Therefore, in a preferred embodiment, the particle size of the modified solder resist ink is 80um to 300um, so as to better reduce the probability of penetration of the modified solder resist ink, thereby better ensuring the clarity of the circuit pattern of the bare board with thick copper dense circuit.

[0062] In one embodiment, the preparation of the modified solder resist ink includes the following steps: first, barium sulfate, epoxy resin, acrylate, amine compound and diethylene glycol ethyl ether acetate are stirred and mixed to obtain an ink mixture; wherein the stirring speed is: 1000r / d~1500r / d; and the stirring time is 12min~20min.

[0063] It can be understood that if the stirring speed is too low or the stirring time is too short, the larger particles of the modified solder resist ink cannot be broken up, resulting in a large number of large particles still existing in the modified solder resist ink. If the stirring speed is too high or the stirring time is too long, the particle size of the modified solder resist ink will be too small to affect the clarity of the circuit pattern of the bare board with thick copper dense circuits. Therefore, in the present disclosure, by controlling the stirring speed to be: 1000r / d~1500r / d; stirring time is 12min~20min, so as to ensure that the particle size of the modified solder resist ink prepared subsequently is more suitable, that is, the particle size of the modified solder resist ink is between 80um~300um; then, the ink mixture is vacuumed to effectively remove the bubbles in the ink mixture to ensure that a bubble-free modified solder resist ink is prepared subsequently, and finally the ink mixture that has been vacuumed is subjected to a third standing operation to further remove the bubbles in the ink mixture, thereby obtaining a bubble-free modified solder resist ink, thereby reducing the problem of bubble defects in the appearance of the modified solder resist ink layer formed in the end due to the presence of bubbles in the modified solder resist ink itself.

[0064] In one embodiment, the modified solder resist ink includes the following components in parts by weight: 50 to 55 parts of barium sulfate, 30 to 35 parts of epoxy resin, 5 to 10 parts of acrylate, 1 to 5 parts of amine compound and 1 to 5 parts of diethylene glycol ethyl ether acetate.

[0065] In one embodiment, the vacuuming operation time is 5 minutes to 10 minutes, and the vacuuming operation pressure is -300Mpa to -200Mpa, so as to ensure that the bubbles in the ink mixture are removed more comprehensively, especially when the third standing operation time is 20 minutes to 30 minutes, so as to more comprehensively remove the bubbles in the ink mixture.

[0066] It is understandable that due to the reduction in particle size and viscosity of the modified solder resist ink, if the traditional printing speed greater than 300mm / s is used, the silk screen printing operation will easily cause the modified solder resist ink to be unevenly distributed, blurred, penetrated, have poor adhesion, and easily generate bubbles on the bare board with thick copper dense circuits. Therefore, in one embodiment, the printing speed of the silk screen printing operation on the first side is 200 mm / s to 300 mm / s, so as to ensure that the printing speed of the silk screen printing operation can better match the printing requirements of the modified solder resist ink, so as to ensure that the modified solder resist ink can be evenly and firmly attached to the thick copper dense circuit bare board, thereby ensuring that the first solder resist ink layer will not be unevenly distributed, blurred, infiltrated, have poor adhesion and be prone to bubble generation. In particular, when the particle size of the modified solder resist ink is less than 300 um and the viscosity of the modified solder resist ink is 95 pda.s to 115 pda.s, while ensuring the uniformity of the first solder resist ink layer, the connection reliability of the first solder resist ink layer and the thick copper dense circuit bare board is also guaranteed, and the edge of the first solder resist ink layer is free of ink leakage and dislocation. It is also ensured that the circuit pattern clarity of the first side of the thick copper dense circuit bare board is high, and it is also ensured that there are no hole defects inside and outside the first solder resist ink layer.

[0067] Likewise, in one embodiment, the printing speed of the second-side screen printing operation is controlled to be 200 mm / s to 300 mm / s to ensure that the second solder resist ink layer has the same characteristics as the first solder resist ink layer.

[0068] It can be understood that although the problem of bubbles in the first solder resist ink layer can be reduced to a certain extent by improving the particle size of the modified solder resist ink, there are still a small number of bubbles in the uncured first solder resist ink layer formed after the first-side screen printing operation. In order to more comprehensively remove the bubbles in the uncured first solder resist ink layer, it is necessary to perform a static operation on the thick copper dense circuit board A after the first-side screen printing operation. Specifically, in one embodiment, the time of the first static operation is 0.5h to 2h to achieve comprehensive removal of bubbles in the uncured first solder resist ink layer, so as to ensure that the first solder resist ink layer can be prepared later without hole defects inside and outside.

[0069] It can also be understood that, since the particle size and viscosity of the modified solder resist ink are reduced in the present disclosure, the particle size and viscosity of the modified solder resist ink in the present disclosure are more suitable, so that the modified solder resist ink generates fewer bubbles after the first screen printing operation, and thus the present disclosure can completely remove the bubbles in the first solder resist ink layer with less standing time, thereby shortening the solder resist production efficiency. Specifically, in some preferred embodiments, the time of the first standing operation is 0.5h to 1h, compared with the traditional 2h to 3h, so that the first solder resist ink layer of the present disclosure can achieve the complete removal of bubbles in the first solder resist ink layer under a shorter standing time (0.5h to 1h), thereby ensuring that the first solder resist ink layer prepared has no hole defects inside and outside.

[0070] Similarly, the second solder resist ink layer has a standing time similar to the first solder resist ink layer. Specifically, in one embodiment, the second standing operation time is 0.5h to 2h to ensure that the second solder resist ink layer can be prepared later without hole defects inside and outside. Further, the second standing operation time is 0.5h to 1h to ensure that the second solder resist ink layer disclosed in the present invention can achieve comprehensive removal of bubbles in the second solder resist ink layer under a shorter standing time (0.5h to 1h), thereby ensuring that the second solder resist ink layer prepared has no hole defects inside and outside.

[0071] It can be understood that in actual applications, the screen printing surface is usually placed upward or vertically when the device is placed flat during static operation, which will make it difficult for bubbles in the first solder resist ink layer and the second solder resist ink layer to escape, thereby failing to achieve rapid and comprehensive escape of bubbles in the first solder resist ink layer. Most people think that if the first and second solder resist ink layers that have just been silk-screened are operated with the silk-screen surface facing downward, they will be prone to falling off under the action of their own gravity because they are not solidified. In fact, the result is not as we get from theoretical logical analysis, that is, when the silk-screen surface is facing downward when placed flat, the unsolidified first and second solder resist ink layers will not fall off. The main reason is that the modified solder resist ink has certain adhesion and thermal curing properties, so that the modified solder resist ink can adhere better to the thick copper intensive circuit bare board and will not fall off, and the surrounding area has a certain temperature when it is stationary, so that the surface of the modified solder resist ink in contact with the air will slowly solidify, thereby improving the connection firmness of the first solder resist ink layer, the second solder resist ink layer and the thick copper intensive circuit bare board, that is, after the first solder resist ink layer and the second solder resist ink layer are stationary, the first solder resist ink layer The surfaces of the first solder resist ink layer and the second solder resist ink layer will solidify while the interior will not solidify, and as the standing time goes by, when the silk screen surface of the thick copper dense circuit board A is kept downward, under the action of gravity, the bubbles in the first solder resist ink layer move toward the surface of the uncured first solder resist ink layer, so that the bubbles are more easily pushed to the surface of the first solder resist ink layer and escape; and when the silk screen surface of the thick copper dense circuit board A is kept downward, the area of ​​the first solder resist ink layer in contact with the air is relatively reduced, which helps to reduce the pressure inside the first solder resist ink layer, thereby facilitating the bubbles to escape from the first solder resist ink layer more easily; and when the silk screen surface of the thick copper dense circuit board A is kept downward, the surface tension of the first solder resist ink layer in contact with the air is reduced, thereby facilitating the bubbles to escape from the first solder resist ink layer more easily, thereby achieving rapid and comprehensive escape of the bubbles in the first solder resist ink layer, and shortening the time of the first standing operation.

[0072] It can also be understood that since the first solder resist ink layer and the second solder resist ink layer just silk-screened have a certain fluidity, when the silk-screen surface is kept downward, the modified solder resist ink can spread and flow better under the action of gravity, so that the bubbles in the modified solder resist ink can be better squeezed out and brought to the surface of the modified solder resist ink, which is not only conducive to the preparation of the first solder resist ink layer and the second solder resist ink layer with high uniformity and relatively consistent thickness distribution, but also to ensure that after one printing, the modified solder resist ink on the copper surface and copper corners of the thick copper dense circuit bare board has the required thickness, good uniformity, high flatness, and no bubble defects in appearance.

[0073] It can also be understood that in order to achieve rapid and comprehensive escape of bubbles in the first solder resist ink layer, a hollow static frame is used as a support to ensure that the first solder resist ink layer is in full contact with the air, thereby achieving rapid and comprehensive escape of bubbles in the first solder resist ink layer.

[0074] Similarly, in one of the embodiments, the second static operation includes the following specific steps: when the thick copper dense circuit board C is placed flat on the hollow static rack, the silk screen surface of the thick copper dense circuit board C is kept downward, so as to achieve rapid and comprehensive escape of bubbles in the second solder resist ink layer, shorten the time of the second static operation, and facilitate the preparation of a second solder resist ink layer with high uniformity and relatively consistent thickness distribution.

[0075] In one embodiment, the hollow static rack includes a frame and a plurality of hollow racks, the plurality of hollow racks are arranged in sequence along the length direction of the frame, the area of ​​the hollow region of each hollow rack is larger than the total area of ​​the circuit diagram of the thick copper dense circuit bare board, and the hollow region of each hollow rack is smaller than the total area of ​​the thick copper dense circuit bare board, so that when the thick copper dense circuit board A or the thick copper dense circuit board C is placed in the hollow rack, the first solder resist ink layer and the second solder resist ink layer that have just been silk-screened can be completely exposed in the hollow region of the hollow rack, so as to avoid the first solder resist ink layer and the second solder resist ink layer from being directly in contact with the air due to the obstruction of the hollow rack, thereby affecting the rapid escape of bubbles in the first solder resist ink layer and the second solder resist ink layer. In addition, since the plurality of hollow racks are arranged in sequence along the length direction of the frame, a plurality of thick copper dense circuit boards A and a plurality of thick copper dense circuit boards C can be placed at the same time, further improving the static efficiency of the plurality of thick copper dense circuit boards A and a plurality of thick copper dense circuit boards C.

[0076] In one of the embodiments, the temperature of the first pre-drying is 73°C to 75°C, and the time of the first pre-drying is 20min to 30min, so as to ensure that the first solder resist ink layer can be initially formed and fixed on the first side of the thick copper dense circuit bare board, and effectively avoid the problem of the first solder resist ink layer falling off and being severely worn during the subsequent second-side silk screen printing operation; and the first pre-drying operation can more comprehensively remove the bubbles in the first solder resist ink layer.

[0077] Similarly, in one of the embodiments, the temperature of the second pre-drying is 73°C to 75°C, and the time of the second pre-drying is 20min to 30min, so as to ensure that the second solder resist ink layer can be better initially formed and fixed on the second side of the thick copper dense circuit bare board, effectively avoiding the problem of the second solder resist ink layer falling off and severe wear during the subsequent second-side silk screen printing operation; and the second pre-drying operation can more comprehensively remove the bubbles in the second solder resist ink layer.

[0078] In one of the embodiments, the pre-baking operation temperature is 60° C. to 130° C., and the pre-baking time is 2 h to 4 h, so as to achieve sufficient and comprehensive curing of the first solder resist ink layer and the second solder resist ink layer. Furthermore, the pre-baking operation is a multi-step temperature rising and baking operation, first, the temperature is raised to 60℃~70℃ for 30 minutes, then, the temperature is raised to 80℃~90℃ for 30 minutes, then, the temperature is raised to 100℃~120℃ for 30 minutes; finally, the temperature is raised to 130℃ for 30 minutes to ensure that the first solder resist ink layer and the second solder resist ink layer can be slowly cured, effectively avoiding the problem of bubbles and holes in the first solder resist ink layer and the second solder resist ink layer caused by the first solder resist ink layer and the second solder resist ink layer being decomposed too quickly due to the rapid temperature rise inside the first solder resist ink layer and the second solder resist ink layer, so as to ensure that the edges of the prepared first solder resist ink layer and the second solder resist ink layer have no ink leakage and dislocation problems, and also ensure that the circuit pattern clarity on both sides of the thick copper dense circuit bare board is high, and also ensure that there are no hole defects inside and outside the first solder resist ink layer and the second solder resist ink layer.

[0079] The present disclosure also provides a thick copper dense circuit board for new energy vehicles, which is prepared by using the process for improving solder mask bubbles in thick copper dense circuit boards for new energy vehicles in any of the above embodiments. It can be understood that the process for improving solder mask bubbles in thick copper dense circuit boards of new energy vehicles disclosed in the present invention improves the particle size and viscosity of the modified solder mask ink, and at the same time cooperates with the printing speed of the first-side silk screen printing operation and the second-side silk screen printing operation, the pressure of the silk screen scraper, the first static operation, the second static operation, the first pre-drying, the second pre-drying and the pre-baking operation. In this way, the problems of many pinhole bubbles, ink not being able to be oiled, and bubbles being easily generated between dense circuits in thick copper dense circuit boards of new energy vehicles are solved, which not only simplifies the solder mask process flow, but also improves the solder mask production efficiency, and ensures that the first solder mask ink layer and the second solder mask ink layer prepared subsequently have no hole defects inside and outside, and also improves the flatness and uniformity of the first solder mask ink layer and the second solder mask ink layer, and ensures that the connection reliability of the first solder mask ink layer and the second solder mask ink layer with the thick copper dense circuit bare board is good, and also ensures that there is no ink leakage and misalignment at the edges of the first solder mask ink layer and the second solder mask ink layer, and also ensures that the circuit pattern of the thick copper dense circuit bare board is clear, readable and accurate. It is particularly suitable for applications where the thickness of the bottom copper layer of a bare board with thick copper dense circuits is ≥1.5OZ, and the circuit spacing of the bare board with thick copper dense circuits is 80um-300um.

[0080] In a preferred embodiment, a thick copper dense circuit board for new energy vehicles is prepared by the following steps: first, a thick copper dense circuit bare board with a bottom copper layer thickness of 4.0OZ and a circuit spacing of 250um is obtained; then, 50 parts of barium sulfate, 35 parts of epoxy resin, 10 parts of acrylate, 1 part of amine compound and 1 part of diethylene glycol ethyl ether acetate are put into a mixing tank and stirred at 1200r / d for 15min to obtain an ink mixture; then, the ink mixture is evacuated at a vacuum pressure of -300Mpa for 8min, and then a third static operation is performed for 30min to obtain a particle size A modified solder resist ink with a thickness of 200um and a viscosity of 110pda.s is prepared; next, the modified solder resist ink is used to perform a first screen printing operation on the thick copper dense circuit bare board, wherein the printing speed of the first screen printing operation is 280mm / s, and the pressure of the screen printing scraper is 0.5Mpa, to obtain a thick copper dense circuit board A; then, when the thick copper dense circuit board A is placed flat on a hollow static rack, the screen printing surface of the thick copper dense circuit board A is kept downward for a first static operation of 0.5h; then, the thick copper dense circuit board A after the first static operation is subjected to a first pre-drying operation, The temperature of the first pre-drying operation is 73°C and the time is 20 minutes, and a thick copper dense circuit board B is obtained; then, the modified solder resist ink is used to perform a second screen printing operation on the thick copper dense circuit board B, the printing speed of the second screen printing operation is 280 mm / s, and the pressure of the screen printing scraper is 0.5 MPa, and a thick copper dense circuit board C is obtained; then, when the thick copper dense circuit board C is placed flat on the hollow static rack, the screen printing surface of the thick copper dense circuit board C is kept downward for a second static operation of 0.5 hours; the thick copper dense circuit board C after the second static operation is subjected to the second A secondary pre-drying operation, wherein the temperature of the second pre-drying operation is 73°C and the time is 20 minutes to obtain a thick copper dense circuit board D; a pre-bake operation is performed on the thick copper dense circuit board D, wherein the pre-bake operation is a multi-step temperature rise and baking operation, specifically, the temperature is raised to 60°C for 30 minutes, then raised to 90°C for 30 minutes, and then raised to 120°C for 30 minutes; finally, the temperature is raised to 130°C for 30 minutes to obtain a thick copper dense circuit board E; finally, the thick copper dense circuit board E is sequentially exposed and developed to obtain the thick copper dense circuit board for new energy vehicles.

[0081] The thick copper dense circuit board for new energy vehicles prepared as above is subjected to appearance inspection: the first solder resist ink layer and the second solder resist ink layer have no hole defects inside and outside, high flatness, good uniformity, not easy to fall off, no ink leakage and no misalignment at the edges of the first solder resist ink layer and the second solder resist ink layer, and the circuit pattern of the thick copper dense circuit bare board is clear, readable and accurate, to ensure that the modified solder resist ink on the copper surface and copper corners of the thick copper dense circuit board of new energy vehicles has the required thickness, good uniformity, high flatness, and no bubble defects in appearance. In addition, improving the solder resist bubble process of thick copper dense circuit boards for new energy vehicles not only simplifies the solder resist process, but also improves the solder resist production efficiency.

[0082] Compared with the prior art, the present invention has at least the following advantages:

[0083] 1) By controlling the particle size of the modified solder resist ink to be less than 300um and the viscosity of the modified solder resist ink to be 95pda.s-115pda.s, the modified solder resist ink has good fluidity and the particle size of the modified solder resist ink is small, which effectively avoids the problem of the ink not being able to oil, and at the same time, in conjunction with the first static operation and the second static operation, effectively reduces the problem of large particles in the modified solder resist ink causing the subsequent high-temperature cured modified solder resist ink layer to have cavities and bubbles inside, resulting in poor appearance of depressions and unevenness; and, the modified solder resist ink with a smaller particle size can be better filled in the spacing of the thick copper dense circuit, effectively avoiding the modified solder resist ink filling at the corners of the thick copper dense circuit. There are small gaps, which causes the modified solder resist ink layer to be unable to achieve good protection of the corners of the thick copper dense circuit and the spacing of the thick copper dense circuit, that is, in the present disclosure, by controlling the particle size of the modified solder resist ink to be less than 300um When the viscosity of the modified solder resist ink is 95pda.s~115pda.s, on the premise of solving the problem of ink not oiling, the compactness of the modified solder resist ink layer in the corners of thick copper dense circuits and the circuit spacing is improved, which not only realizes the reliable and firm connection between the modified solder resist ink and the corners of thick copper dense circuits and the spacing of thick copper dense circuits, but also realizes better protection of the corners of thick copper dense circuits and the spacing of thick copper dense circuits, and can effectively reduce the probability of hole defects in the first solder resist ink layer and the second solder resist ink layer finally formed; it also reduces the problem of poor appearance of depression and unevenness caused by the presence of a large number of large particles in the subsequent high-temperature cured modified solder resist ink layer, which is particularly suitable for applications where the thickness of the bottom copper layer of the thick copper dense circuit bare board is ≥1.5OZ, and the circuit spacing of the thick copper dense circuit bare board is 80um~300um.

[0084] 2) Compared with the traditional secondary printing, the present invention improves the particle size and viscosity of the modified solder resist ink, and can solve the problems of many pinhole bubbles, ink failure and easy generation of bubbles between dense circuits in the thick copper dense circuit boards of new energy vehicles with only one printing. It not only simplifies the solder resist process, but also improves the solder resist production efficiency.

[0085] The above-mentioned embodiments only express several implementation methods of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the disclosed patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the disclosed patent shall be subject to the attached claims.

Claims

1. A process for improving solder mask bubbles in thick copper dense circuit boards for new energy vehicles, characterized in that: Get thick copper dense circuit bare board; The first side of the thick copper dense circuit bare board is screen printed with modified solder resist ink to obtain a thick copper dense circuit board A; wherein the particle size of the modified solder resist ink is less than 300 um, and the viscosity of the modified solder resist ink is 95 pda.s to 115 pda.s; Performing a first static operation on the thick copper dense circuit board A; Performing a first pre-drying operation on the thick copper dense circuit board A after the first static operation to obtain a thick copper dense circuit board B; The modified solder resist ink is used to perform a second-side screen printing operation on the thick copper dense circuit board B to obtain a thick copper dense circuit board C; Performing a second static operation on the thick copper dense circuit board C; Performing a second pre-drying operation on the thick copper dense circuit board C after the second static operation to obtain a thick copper dense circuit board D; Pre-baking the thick copper dense circuit board D to obtain a thick copper dense circuit board E; The thick copper dense circuit board E is sequentially subjected to exposure operation and development operation to obtain the thick copper dense circuit board for new energy vehicles.

2. The process for improving solder mask bubbles in thick copper dense circuit boards for new energy vehicles according to claim 1 is characterized in that: The preparation of the modified solder resist ink comprises the following steps: The barium sulfate, epoxy resin, acrylate, amine compound and diethylene glycol ethyl ether acetate are stirred and mixed to obtain an ink mixture; wherein the stirring speed is: 1000r / d to 1500r / d; the stirring time is 12min to 20min; Performing a vacuum operation on the ink mixture; The ink mixture that has undergone the vacuuming operation is subjected to a third static operation to obtain the modified solder resist ink.

3. The process for improving solder mask bubbles in thick copper dense circuit boards for new energy vehicles according to claim 2 is characterized in that: The vacuuming operation time is 5 min to 10 min, and the vacuuming operation pressure is -300 MPa to -200 MPa; and / or, The time of the third standing operation is 20 minutes to 30 minutes.

4. The process for improving solder mask bubbles in thick copper dense circuit boards for new energy vehicles according to claim 1 is characterized in that: The printing speed of the first screen printing operation is 200 mm / s to 300 mm / s; the pressure of the screen printing scraper is 0.4 Mpa to 0.6 Mpa; and / or, The printing speed of the second-side screen printing operation is 200 mm / s to 300 mm / s.

5. The process for improving solder mask bubbles in thick copper dense circuit boards for new energy vehicles according to claim 1 is characterized in that: The time of the first standing operation is 0.5h to 2h.

6. The process for improving solder mask bubbles in thick copper dense circuit boards for new energy vehicles according to claim 1 is characterized in that: The second standing operation time is 0.5h to 2h.

7. The process for improving solder mask bubbles in thick copper dense circuit boards for new energy vehicles according to claim 1 is characterized in that: The thickness of the bottom copper layer of the thick copper dense circuit bare board is ≥1.5OZ, and the circuit spacing of the thick copper dense circuit bare board is 80um-300um.

8. The process for improving solder mask bubbles in thick copper dense circuit boards for new energy vehicles according to claim 1 is characterized in that: The first static operation includes the following specific steps: when the thick copper dense circuit board A is placed flat on the hollow static rack, the silk screen surface of the thick copper dense circuit board A is kept downward; and / or, The second static operation includes the following specific steps: when the thick copper dense circuit board C is placed flat on the hollow static rack, the silk screen surface of the thick copper dense circuit board C is kept downward.

9. The process for improving solder mask bubbles in thick copper dense circuit boards for new energy vehicles according to claim 1 is characterized in that: The temperature of the first pre-drying is 73° C. to 75° C., and the time of the first pre-drying is 20 min to 30 min.

10. A thick copper dense circuit board for new energy vehicles, characterized in that: The method is prepared by using the process for improving solder mask bubbles in thick copper dense circuit boards for new energy vehicles as described in any one of claims 1 to 9.

Images