Method for preparing solder mask of circuit board based on plugging hole processing and circuit board

Abstract

The present application provides a method for preparing solder mask for a circuit board based on plugging hole treatment and a circuit board. The above-mentioned method for preparing solder mask for a circuit board based on plugging hole treatment, the present application provides a method for preparing solder mask for a circuit board based on plugging hole treatment, comprising the following steps: providing a board body, plugging the via hole with a dual-curing resin, and then performing a thermal curing operation to form a resin plug with an inner depression in the via hole, and performing a silk screen solder mask operation, a vacuum operation, a photocuring operation, and a baking operation on the first and second surfaces of the board body formed with the resin plug, respectively, to solidify the solder mask ink. Through this method, the bonding force between the board surface oil and the resin plug in the plug hole can be increased, the connection strength between the solder mask ink layer and the board body can be improved, and the via hole of the board body can be better protected, which is particularly suitable for the application of new energy vehicles in harsh environments.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit board production, and in particular to a method for preparing a circuit board solder mask based on via plugging treatment and a circuit board. Background Art

[0002] Circuit board is also called PCB (Printed Circuit Board), and its Chinese name is printed circuit board, also known as printed circuit board. It is an important electronic component, a support for electronic components, and a carrier for electrical connections between electronic components.

[0003] During the production process of circuit boards, it is usually necessary to print solder mask on the circuit boards, so that a layer of solder mask ink is coated on the circuit boards except for the pads, vias and other locations used for welding, and the solder mask ink is cured. In this way, a layer of solder mask ink can be formed on the surface of the circuit boards to protect the circuit boards.

[0004] For example, patent CN106413264B discloses a method for making a PCB with solder resist ink plugging holes, and specifically discloses the use of solder resist ink for plugging holes and silk-screen solder resist to fill the via holes on the production board, and silk-screen solder resist ink on the welding surface and component surface of the production board; then the production board is placed under normal pressure or the production board is vacuumed. It can be seen that the traditional practice is to use plugging technology and vacuuming to process the printing of solder resist ink. However, if only the plugging technology is used, the solder resist ink layer needs to be left to stand for a long time, that is, it takes 45 to 60 minutes to complete the solder resist ink layer standing operation, which affects the production efficiency; if only vacuuming is used, there will be more solder resist ink residue in the via hole, which increases the difficulty of subsequent cleaning. When the plugging technology is used for solder resist ink, since the solder resist ink in the plug hole has been completely solidified, it affects the bonding strength between the circuit board surface oil and the solder resist ink in the plug hole, thereby reducing the connection strength between the solder resist ink layer and the circuit board, that is, it is easy to fall off during use. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing solder resist for a circuit board based on plugging treatment and a circuit board that can improve the bonding strength between the circuit board surface oil and the inner recessed resin plug to obtain a solder resist ink layer with good flatness, good appearance, and strong connectivity, and has high production efficiency.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A method for preparing solder mask of a circuit board based on via plugging treatment comprises the following steps:

[0008] Providing a plate body, wherein the plate body is formed with a conducting hole;

[0009] Using a dual-curing resin to plug the via hole of the board body to form a dual-curing resin column in the via hole of the board body;

[0010] Performing a thermal curing operation on the plate body with the dual-curing resin column formed thereon to form a recessed resin plug in the via hole;

[0011] Performing a silk screen solder resist operation on the first surface and the second surface of the board body formed with the resin plug respectively;

[0012] Vacuum the board after silk screen solder mask operation;

[0013] Performing light curing operation on the plate after vacuuming operation;

[0014] The board body after the light curing operation is baked.

[0015] In one embodiment, the dual-cure resin is a photo-thermal dual-cure resin.

[0016] In one embodiment, the heat curing operation is performed at a temperature of 90° C. to 150° C. and a time of 5 min to 15 min.

[0017] In one embodiment, the photocuring operation is performed under ultraviolet light irradiation for 3 minutes to 5 minutes.

[0018] In one embodiment, the vacuum operation is performed under conditions of 90 kPa to 100 kPa for 5 to 10 minutes.

[0019] In one embodiment, the step of baking the board after the light curing operation includes the following specific steps:

[0020] The plate is tilted and placed in a 70°C to 75°C baking oven for baking for 25min to 55min.

[0021] In one embodiment, the inclination angle of the plate is 1 degree to 5 degrees.

[0022] In one embodiment, a 32T or 43T grid is used for silk screen solder mask operation.

[0023] In one embodiment, the diameter of the via hole is 0.2 mm to 0.3 mm.

[0024] A circuit board is prepared by using the method for preparing a circuit board solder resist based on via plugging treatment described in any of the above embodiments.

[0025] Compared with the prior art, the present invention has at least the following advantages:

[0026] 1. The above-mentioned method for preparing solder mask for a circuit board based on plugging treatment uses a dual-cured resin to plug the via hole to form a dual-cured resin column in the via hole, which can prevent the solder mask ink from falling into the via hole during the subsequent silk-screen solder mask operation, thereby reducing the difficulty of subsequent cleaning. The plate body with the dual-cured resin column is then thermally cured to allow the dual-cured resin column to undergo a predetermined shape under heating conditions to form a recessed resin plug in the via hole. In this way, on the one hand, most of the dual-cured resin column is cured so that the dual-cured resin will not be drawn away during the subsequent vacuum operation. On the other hand, the recessed resin plug formed in the via hole can provide a better attachment point for the solder mask ink during the subsequent silk-screen solder mask operation, that is, the solder mask ink can flow better into the recessed resin plug to form a mosaic The structure can increase the bonding force between the first and second side oils of the board and the resin plug in the plug hole, thereby increasing the connection strength between the solder resist ink layer and the board, effectively avoiding the phenomenon of easy falling off during use, and then vacuuming the board to quickly remove the bubbles in the solder resist ink, while allowing the solder resist ink to be better cast and spread on the first and second sides of the board to obtain a solder resist ink layer with better flatness and fewer bubbles, and then photocuring the board to further cure the recessed resin plug to increase the bonding force between the first and second side oils of the board and the recessed resin plug, and finally baking to further cure the solder resist ink so that the solder resist ink layer and the recessed resin plug form a stable interlocking structure, further improving the connection strength between the recessed resin plug and the first and second side oils of the board.

[0027] 2. Compared with traditional solder mask printing, the above-mentioned method for preparing solder mask for circuit boards based on plugging has better compatibility and can be applied to both plugging technology and vacuuming technology. On the one hand, it can reduce the standing time of solder mask ink, making the entire production process relatively compact and fast, that is, improving production efficiency. On the other hand, it avoids the trouble of switching between two different production lines, so as to quickly obtain a solder mask ink layer with good flatness, good appearance and strong connectivity. At the same time, since the via holes of the board body are plugged, the via holes of the board body can be better protected, which is especially suitable for the application of new energy vehicles in some harsh environments, thereby increasing the service life of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention 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 creative work.

[0029] Figure 1 The present invention is a flowchart of a method for preparing a solder mask for a circuit board based on via plugging. DETAILED DESCRIPTION

[0030] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention 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 invention more thoroughly understood.

[0031] 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.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to suppress the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0033] The present application provides a method for preparing solder mask for a circuit board based on plugging treatment, comprising the following steps: providing a board body, wherein the board body is formed with a via hole; plugging the via hole of the board body with a dual-cured resin to form a dual-cured resin column in the via hole of the board body; performing a thermal curing operation on the board body with the dual-cured resin column formed thereon to form a resin plug with an inner recess in the via hole; performing a silk-screen solder mask operation on the first side and the second side of the board body formed with the resin plug, respectively; performing a vacuum operation on the board body after the silk-screen solder mask operation; performing a photocuring operation on the board body after the vacuum operation; and performing a baking operation on the board body after the photocuring operation.

[0034] The above-mentioned method for preparing solder mask for circuit board based on plugging treatment uses dual-cured resin to plug the via hole to form a dual-cured resin column in the via hole, which can prevent the solder mask ink from falling into the via hole during the subsequent silk-screen solder mask operation, thereby reducing the difficulty of subsequent cleaning. The board body with the dual-cured resin column is then thermally cured to allow the dual-cured resin column to undergo a predetermined shape under heating conditions to form a recessed resin plug in the via hole. In this way, on the one hand, most of the dual-cured resin column is cured so that the dual-cured resin will not be drawn away during the subsequent vacuum operation. On the other hand, the recessed resin plug formed in the via hole can provide a better attachment point for the solder mask ink during the subsequent silk-screen solder mask operation, that is, the solder mask ink can flow better into the recessed resin plug to form a mosaic. The structure can increase the bonding force between the first and second side oils of the board and the resin plug in the plug hole, thereby increasing the connection strength between the solder resist ink layer and the board, effectively avoiding the phenomenon of easy falling off during use, and then vacuuming the board to quickly remove the bubbles in the solder resist ink, while allowing the solder resist ink to be better cast and spread on the first and second sides of the board to obtain a solder resist ink layer with better flatness and fewer bubbles, and then photocuring the board to further cure the recessed resin plug to increase the bonding force between the first and second side oils of the board and the recessed resin plug, and finally baking to further cure the solder resist ink so that the solder resist ink layer and the recessed resin plug form a stable interlocking structure, further improving the connection strength between the recessed resin plug and the first and second side oils of the board. Furthermore, the above-mentioned method for preparing solder mask for circuit board based on plugging treatment has better compatibility than traditional solder mask printing, and can be applied to both plugging technology and vacuuming technology. On the one hand, it can reduce the standing time of solder mask ink, making the entire production process relatively compact and fast, that is, improving production efficiency. On the other hand, it avoids the trouble of switching between two different production lines, so as to quickly obtain a solder mask ink layer with good flatness, good appearance and strong connectivity. At the same time, since the conductive holes of the board body are plugged, the conductive holes of the board body can be better protected, which is especially suitable for the application of new energy vehicles in some harsh environments, thereby increasing the service life of the circuit board.

[0035] See also Figure 1 In order to better understand the technical solution and beneficial effects of the present application, the present application is further described in detail below in conjunction with specific embodiments. A method for preparing a solder mask for a circuit board based on via plugging treatment in one embodiment includes some or all of the following steps:

[0036] S110, providing a board, wherein the board is formed with a via hole, that is, the board is made through an outer layer circuit, and a via hole and a pad are formed on the board.

[0037] S120, plugging the via holes of the board body with a dual-curing resin to form dual-curing resin columns in the via holes of the board body.

[0038] It can be understood that since the dual-cure resin is used to plug the via holes to form dual-cure resin columns in the via holes, the via holes can be sealed, which can prevent the solder resist ink from falling into the via holes during the subsequent silk screen solder resist operation, thereby reducing the subsequent cleaning difficulty, and is also beneficial for the subsequent solder resist ink to be better spread and laid on the first and second surfaces of the board, so as to ensure a solder resist ink layer with better flatness and fewer bubbles.

[0039] S130, performing a thermal curing operation on the plate body with the dual-curing resin column formed thereon to form an inner-recessed resin plug in the conducting hole.

[0040] It can be understood that if the board with dual-curing resin columns is not thermally cured, the dual-curing resin columns in the plugging holes will still be fluid and easily be sucked away during the subsequent vacuum operation, thereby failing to achieve the plugging effect. It is also not conducive to the subsequent solder mask printing operation, and it is easy to cause the solder mask ink layer to become uneven, have many bubbles, and other undesirable phenomena. The present application performs a heat-curing operation on the board body with the attached dual-cured resin column so that the dual-cured resin column can be pre-shaped under heated conditions to form a recessed resin plug in the conductive hole. In this way, on the one hand, most of the dual-cured resin column is cured so that the dual-cured resin will not be sucked away during the subsequent vacuum operation. On the other hand, the recessed resin plug formed in the conductive hole can provide a better attachment point for the solder resist ink during the subsequent silk screen solder resist operation, that is, the solder resist ink can better flow into the recessed resin plug to form a mosaic structure. In this way, the bonding force between the first side oil and the second side oil of the board body and the resin plug in the plug hole can be increased, thereby improving the connection strength between the solder resist ink layer and the board body, and effectively avoiding the phenomenon of easy falling off during use.

[0041] S140, performing a silk screen solder resist operation on the first surface and the second surface of the board body formed with the resin plug, respectively.

[0042] It can be understood that by performing a silk screen solder resist operation on the first and second surfaces of the board body formed with the resin plug, a first surface oil is obtained on the first surface of the board body and a second surface oil is obtained on the second surface. The surface oil referred to in this application refers to the solder resist ink layer printed on the first or second surface of the board body. When the silk screen solder resist operation is performed on the first or second surface, the solder resist ink can flow well into the inner recessed resin plug to form an interlocking structure to ensure that a stable interlocking structure is obtained later, so as to greatly improve the bonding force between the surface oil and the inner recessed resin plug, thereby improving the connection strength between the inner recessed resin plug and the first surface oil and the second surface oil of the board body.

[0043] S150, performing a vacuum operation on the board after the silk screen solder mask operation.

[0044] It can be understood that the board body after the silk screen solder resist operation is vacuumed to quickly remove the bubbles in the solder resist ink, and at the same time, the solder resist ink can be better cast and laid on the first and second surfaces of the board body to obtain a solder resist ink layer with better flatness and fewer bubbles. Compared with the traditional solder resist printing, the compatibility of this application is better, and the plugging technology and the vacuuming technology can be applied at the same time. On the one hand, it can reduce the static time of the solder resist ink, making the entire production process relatively compact and fast, that is, improving the production efficiency. On the other hand, it avoids the trouble of switching between two different production lines, so as to quickly obtain a solder resist ink layer with good flatness, good appearance and strong connectivity. At the same time, since the through holes of the board body are plugged, the through holes of the board body can be better protected, which is particularly suitable for the application of new energy vehicles in some harsh environments, thereby increasing the service life of the circuit board.

[0045] It should be noted that in order to allow the solder resist ink to be better cast and spread on the first and second surfaces of the board, that is, to allow the solder resist ink to better fill the recessed resin plug, it is necessary to first perform a thermal curing operation on the dual-cure resin column so that the dual-cure resin column can be pre-shaped under heating conditions to form a recessed resin plug in the via hole, so as to ensure that during the subsequent vacuum operation, the gas in the solder resist ink can be quickly removed while allowing the solder resist ink to be better cast and spread on the first and second surfaces of the board, so as to obtain a solder resist ink layer with better flatness and fewer bubbles, which greatly saves the standing time of traditional plugging technology, making the entire production process relatively compact and fast, that is, improving production efficiency.

[0046] S160, performing a light curing operation on the plate after the vacuum operation.

[0047] It can be understood that since the dual-curing resin can be cured under heating conditions and can also be further fully cross-linked and cured under light conditions, when the plate body after the vacuum operation is subjected to light curing, the inner recessed resin plug can be further cured, which ensures the connectivity between the first and second surface oils of the plate body and the inner recessed resin plug, and ensures that the inner recessed resin plug that has been cured is not easy to expand under heating conditions during the subsequent baking operation, so as to obtain a chimeric structure with good joint stability.

[0048] S170, baking the board after the light curing operation.

[0049] It can be understood that by baking the board after the photocuring operation, the first side oil and the second side oil of the board can be solidified, so that the solder mask ink layer and the inner recessed resin plug form a stable interlocking structure, thereby further ensuring the connection strength between the inner recessed resin plug and the first side oil and the second side oil of the board.

[0050] The above-mentioned method for preparing solder mask for circuit board based on plugging treatment uses dual-cured resin to plug the via holes to form dual-cured resin columns in the via holes, which can prevent solder mask ink from falling into the via holes during the subsequent silk-screen solder mask operation, thereby reducing the difficulty of subsequent cleaning. The plate body with the dual-cured resin columns is then thermally cured to allow the dual-cured resin columns to undergo a predetermined shape under heating conditions to form a recessed resin plug in the via hole. In this way, on the one hand, most of the dual-cured resin columns are cured so that the dual-cured resin will not be drawn away during the subsequent vacuum operation. On the other hand, the recessed resin plug formed in the via hole can provide a better attachment point for the solder mask ink during the subsequent silk-screen solder mask operation, that is, the solder mask ink can better flow into the recessed resin plug to form an interlocking The structure can increase the bonding force between the first side oil and the second side oil of the board and the resin plug in the plug hole, thereby improving the connection strength between the solder resist ink layer and the board, and effectively avoiding the phenomenon of easy falling off during use. Then, the board is vacuumed to quickly remove the bubbles in the solder resist ink, and at the same time, the solder resist ink can be better cast and spread on the first and second sides of the board to obtain a solder resist ink layer with better flatness and fewer bubbles. Then, the board is photocured to further cure the recessed resin plug to increase the bonding force between the first side oil and the second side oil of the board and the recessed resin plug. Finally, the solder resist ink is further cured through baking, so that the solder resist ink layer and the recessed resin plug form a stable interlocking structure, further improving the connection strength between the recessed resin plug and the first side oil and the second side oil of the board.

[0051] Compared with traditional solder mask printing, the above-mentioned method for preparing solder mask for circuit boards based on plugging has better compatibility and can be applied to both plugging technology and vacuuming technology. On the one hand, it can reduce the standing time of solder mask ink, making the entire production process relatively compact and fast, that is, improving production efficiency. On the other hand, it avoids the trouble of switching between two different production lines, so as to quickly obtain a solder mask ink layer with good flatness, good appearance and strong connectivity. At the same time, since the conductive holes of the board body are plugged, the conductive holes of the board body can be better protected, which is especially suitable for the application of new energy vehicles in some harsh environments, thereby increasing the service life of the circuit board.

[0052] In one embodiment, the dual-cured resin is a photothermal dual-cured resin, so as to ensure that the dual-cured resin can be cured and pre-shaped under heating conditions, and can be completely cross-linked and cured under light conditions.

[0053] In one embodiment, the dual-cure resin includes at least one of a dual-cure acrylic resin, a dual-cure epoxy acrylic resin, and a dual-cure polyurethane acrylic resin.

[0054] It can be understood that since dual-cure acrylic resin, dual-cure epoxy acrylic resin and dual-cure polyurethane acrylic resin all contain acrylic resin, and since acrylic resin has the advantages of high reactivity and less yellowing of cured products, it is ensured that the dual-cure resin column can be quickly pre-shaped under heating conditions, so that it can be shaped on the inner wall of the via to form a recessed resin plug. It should be noted that since the shrinkage rate of acrylic resin is relatively large in the initial stage of thermal curing, the dual-cure resin column in the via can form a recessed resin plug after being pre-shaped by heat, thereby ensuring that the dual-cure resin column can form a recessed resin plug after the thermal curing operation. In addition, due to the inhibition of polymerization by oxygen in the air during the thermal curing operation of the acrylic resin, the surface of the dual-cured resin column is not easy to undergo polymerization reaction and will appear slightly sticky. That is, the surface of the inner recessed resin plug is prone to slightly sticky phenomenon, and the slight stickiness can better adhere to the first side oil and the second side oil, thereby improving the bonding strength between the inner recessed resin plug and the first side oil and the second side oil, thereby greatly improving the bonding strength between the first side oil, the second side oil and the inner recessed resin plug, thereby improving the connection strength between the inner recessed resin plug of the circuit board and the circuit board surface oil.

[0055] In a preferred embodiment, the dual-cure resin is a mixture of the dual-cure acrylic resin, the dual-cure epoxy acrylic resin and the dual-cure polyurethane acrylic resin.

[0056] Furthermore, in a more preferred embodiment, the usage ratio of the dual-cure acrylic resin: the dual-cure epoxy acrylic resin: the dual-cure polyurethane acrylic resin is 2:1:1.

[0057] It can be understood that by controlling the usage ratio of dual-cured acrylic resin: dual-cured epoxy acrylic resin: dual-cured polyurethane acrylic resin to 2:1:1, the specific gravity of the dual-cured acrylic resin is relatively higher than that of the dual-cured epoxy acrylic resin and the dual-cured polyurethane acrylic resin, thereby ensuring that the acrylic resin content in the dual-cured resin is relatively high, so that when the subsequent dual-cured resin column undergoes a heat curing operation, the dual-cured resin column can shrink to a certain extent to form an inner concave resin plug, but the shrinkage rate of the dual-cured resin column is not necessarily greater. Therefore, the present application will be dual-cured acrylic The resin is compounded with dual-cure epoxy acrylic resin and dual-cure polyurethane acrylic resin, so that the shrinkage rate of the dual-cure resin column is relatively appropriate, so as to ensure that the dual-cure resin column can obtain a recessed resin plug after the heat curing operation, and at the same time, it can also quickly undergo light curing to ensure a stable interlocking structure subsequently, that is, to ensure that a resin plug with high connectivity can be formed in the via hole. In this way, the resin plug and the first side oil and the second side oil form a good solder mask ink layer, which has a good protective effect on the via hole of the circuit board, and is particularly suitable for new energy vehicles in some harsh environments, greatly improving the service life of the circuit board.

[0058] Furthermore, the dual-cure acrylic resin, dual-cure epoxy acrylic resin and dual-cure polyurethane acrylic resin can be purchased on the market, for example, from Guangzhou Sanwang Chemical Materials Co., Ltd.

[0059] In one of the embodiments, the step of plugging the via hole with a dual-cure resin includes the following specific steps: injecting the dual-cure resin into the via hole to achieve the plugging operation on the via hole.

[0060] In this embodiment, an injection molding machine is used to plug the conductive hole. It can be understood that the prepared dual-cure resin is pumped into the injection molding machine, and the circuit board is sent to the bottom of the injection needle of the injection molding machine through the conveying component, and then the injection molding machine is started to inject the dual-cure resin into the conductive hole to complete the plugging operation of the conductive hole. The implementation principle of the injection molding machine can be obtained through existing technology, so it is not described in detail in this application.

[0061] In one embodiment, the dual-cured resin column is flush with both ends of the via. It can be understood that by controlling the dual-cured resin column injected into the via hole to be flush with the two ends of the via hole, on the one hand, it is ensured that the injected dual-cured resin column has a larger contact area with the inner wall of the via hole, so as to ensure that the dual-cured resin column can fill a larger area in the via hole, thereby ensuring that the dual-cured resin column and the via hole have stronger connectivity, and on the other hand, it is avoided that the dual-cured resin column after thermal curing will not protrude and be exposed outside the via hole, so as to ensure that when the silk screen solder mask operation is performed later, the first side oil and the second side oil with higher flatness can be obtained on the first side and the second side of the board body, so as to ensure that a solder mask ink layer with good flatness, good appearance and strong connectivity can be obtained later, and on the other hand, it can be ensured that the dual-cured resin column can form a recessed resin plug in the via hole after thermal curing, so that the solder mask ink can be embedded in the recessed resin plug, which can better improve the connection strength between the first side oil, the second side oil, the recessed resin plug and the via hole, so as to ensure a mosaic structure with high connection strength.

[0062] Furthermore, in one of the embodiments, the inner recess of the resin plug has a depth of 0.5 nm to 2 nm.

[0063] In one of the embodiments, when the via hole is prone to leakage during plugging, a laser device can be used to carbonize the edge of the inner-recessed resin plug to effectively remove the excess dual-cured resin at the edge of the inner-recessed resin plug, so as to ensure that the first surface oil and the second surface oil with higher flatness can be obtained in the subsequent silk screen solder mask operation. Furthermore, in one of the embodiments, the edge of the inner-recessed resin plug after laser treatment is adsorbed to adsorb and clean the carbonized dual-cured resin.

[0064] In one embodiment, the conditions of the heat curing operation are a temperature of 90°C to 150°C and a time of 5min to 15min. It is understandable that if the temperature is lower than 90°C and the time is lower than 5min, it is impossible to ensure that the dual-cured resin column can form a recessed resin plug in the conductive hole. If the temperature is higher than 150°C and the time is longer than 15min, it is easy to cause the stickiness of the recessed resin plug to be more serious, which is not conducive to the subsequent vacuuming operation, that is, the sticky resin plug is easily pumped away by the vacuuming operation, thereby affecting the plugging effect. Therefore, the present application controls the conditions of the heat curing operation to be a temperature of 90°C to 150°C and a time of 5min to 15min to ensure that the dual-cured resin column can be pre-shaped under heated conditions to form a recessed resin plug in the conductive hole, and to ensure that the surface of the recessed resin plug is slightly sticky, so as to better improve the bonding force between the recessed resin plug and the first surface oil and the second surface oil.

[0065] In one of the embodiments, the condition of the photocuring operation is 3 minutes to 5 minutes of ultraviolet light irradiation. It is understandable that if the ultraviolet light irradiation is less than 3 minutes, the complete correlation curing of the dual-cured resin column cannot be ensured. If the ultraviolet light irradiation is more than 5 minutes, it is easy to cause the dual-cured resin column to be excessively cross-linked and cured, such as warping and wrinkling, which reduces the service life. Therefore, the present application can effectively ensure that the dual-cured resin column can be completely correlated and cured, and is not prone to warping and wrinkling by controlling the ultraviolet light irradiation for 3 minutes to 5 minutes.

[0066] In one embodiment, the vacuuming operation is performed at 90 kPa to 100 kPa for 5 to 10 minutes. It is understood that if the vacuuming operation is performed at a pressure lower than 90 kPa and the time is less than 5 minutes, the bubbles cannot be removed, and if the vacuuming operation is performed at a pressure higher than 100 kPa and the time is longer than 10 minutes, the slightly sticky dual-curing resin on the surface of the inner concave resin plug is easily removed, thereby affecting the plugging effect. Therefore, in the present application, the vacuum operation conditions are controlled to be 90kpa~100kpa, and the time is 5 minutes~10 minutes, so as to ensure the rapid removal of bubbles in the solder resist ink, and at the same time allow the solder resist ink to be better cast and spread on the first and second surfaces of the board body, so as to obtain a solder resist ink layer with good flatness and fewer bubbles, so as to ensure a good quality circuit board, and at the same time ensure that the slightly sticky dual-curing resin on the surface of the recessed resin plug is not extracted, so as to ensure that the recessed resin plug can be well filled and plugged in the via hole, so as to ensure that the recessed resin plug has a strong connection strength with the inner wall of the via hole, so as to ensure the plugging effect.

[0067] In one of the embodiments, the step of baking the board after the light curing operation includes the following specific steps: placing the board at an angle in a baking oven at 70° C. to 75° C. and baking for 25 min to 55 min.

[0068] It can be understood that if the baking temperature is lower than 70°C and the time is less than 25 minutes, the curing of the solder resist ink cannot be ensured. If the baking temperature is higher than 75°C and the time is longer than 55 minutes, the curing time of the solder resist ink is too long, which may cause warping and wrinkling. Therefore, the present application places the board in a 70°C to 75°C baking oven for 25 minutes to 55 minutes to ensure that the solder resist ink can be completely cured and will not warp or wrinkle. Furthermore, the present application also places the board in an inclined position in the baking oven to ensure that the solder resist ink can be better spread and laid on the first and second surfaces of the board to obtain a solder resist ink layer with better flatness.

[0069] It should be noted that if the board is tilted at a large angle, the solder resist ink will have better fluidity, which will easily lead to uneven thickness of the solder resist ink layer on both sides of the board, and even in severe cases, the solder resist ink layer on one side will turn red, thus affecting the product quality of the circuit board, that is, the solder resist ink layer does not cover the outer layer circuit, and copper exposure is likely to occur. Therefore, in one embodiment, the tilt angle of the board is 1 degree to 5 degrees. By setting the tilt angle to 1 degree to 5 degrees, that is, the tilt angle is small, it can ensure that the solder resist ink can be better spread and laid on the first and second surfaces of the board.

[0070] In order to ensure that the board body can obtain a solder resist ink layer with good flatness, in one embodiment, the board body is turned over and tilted.

[0071] It can be understood that by turning over and tilting the board, the solder resist ink can flow in opposite directions and spread on the first and second surfaces of the board to avoid uneven thickness on both sides of the board, thereby ensuring a solder resist ink layer with good flatness.

[0072] In one of the embodiments, the board is first placed on the left side of the baking oven and baked for 5 to 10 minutes, then the board is turned over and tilted so that the board is placed on the right side of the baking oven and baked for 5 to 10 minutes, and finally the board is placed flat and baked for 15 to 35 minutes to ensure that a solder mask ink layer with good flatness is obtained.

[0073] Furthermore, in one of the embodiments, an ultraviolet lamp is provided in the baking oven, so that the board can directly enter the baking operation after the light curing operation, making the production process more compact and greatly improving the production efficiency.

[0074] In one embodiment, a 32T or 43T grid is used for silk screen solder resist operation to realize the printing of solder resist ink on the first side and the second side of the board.

[0075] In one of the embodiments, the diameter of the via hole is 0.2 mm to 0.3 mm, so as to ensure that the dual-curing resin can be well injected into the via hole to complete the plugging operation.

[0076] The present application also provides a circuit board, which is prepared by using the circuit board solder mask preparation method based on plugging treatment described in any of the above embodiments.

[0077] It can be understood that the circuit board obtained by adopting the circuit board solder mask preparation method based on plugging hole processing of the present application enables the dual-cured resin column to be well filled in the conductive hole, and the first side oil and the second side oil of the board body can be well filled and embedded in the inner recessed resin plug, which greatly improves the connection strength between the first side oil, the second side oil, the inner recessed resin plug and the conductive hole, and effectively avoids the phenomenon that the solder mask ink layer is easy to fall off when the circuit board is in use. At the same time, since the conductive holes of the board body are plugged, the conductive holes of the board body can be better protected, which is particularly suitable for the application of new energy vehicles in some harsh environments, thereby improving the service life of the circuit board, and avoiding the static time of traditional plugging holes, greatly improving the production efficiency of the circuit board solder mask.

[0078] In one embodiment, the circuit board includes a board body, a first surface oil layer, a second surface oil layer and a plurality of recessed resin plugs, a plurality of vias are formed in the board body, each of the recessed resin plugs is arranged in a via hole, and a first recessed end and a second recessed end are respectively formed at both ends of each recessed resin plug, the first surface oil layer is respectively embedded in the first recessed end of each recessed resin plug, and the first surface oil layer is respectively embedded in the second recessed end of each recessed resin plug, so that the first surface oil layer and the second surface oil layer and the plurality of recessed resin plugs form a highly connected embedded structure, which greatly improves the connection strength between the first surface oil, the second surface oil, the recessed resin plugs and the vias, and effectively avoids the phenomenon that the solder resist ink layer is easy to fall off when the circuit board is in use.

[0079] Compared with the prior art, the present invention has at least the following advantages:

[0080] 1. The above-mentioned method for preparing solder mask for a circuit board based on plugging treatment uses a dual-cured resin to plug the via hole to form a dual-cured resin column in the via hole, which can prevent the solder mask ink from falling into the via hole during the subsequent silk-screen solder mask operation, thereby reducing the difficulty of subsequent cleaning. The plate body with the dual-cured resin column is then thermally cured to allow the dual-cured resin column to undergo a predetermined shape under heating conditions to form a recessed resin plug in the via hole. In this way, on the one hand, most of the dual-cured resin column is cured so that the dual-cured resin will not be drawn away during the subsequent vacuum operation. On the other hand, the recessed resin plug formed in the via hole can provide a better attachment point for the solder mask ink during the subsequent silk-screen solder mask operation, that is, the solder mask ink can flow better into the recessed resin plug to form a mosaic The structure can increase the bonding force between the first and second side oils of the board and the resin plug in the plug hole, thereby increasing the connection strength between the solder resist ink layer and the board, effectively avoiding the phenomenon of easy falling off during use, and then vacuuming the board to quickly remove the bubbles in the solder resist ink, while allowing the solder resist ink to be better cast and spread on the first and second sides of the board to obtain a solder resist ink layer with better flatness and fewer bubbles, and then photocuring the board to further cure the recessed resin plug to increase the bonding force between the first and second side oils of the board and the recessed resin plug, and finally baking to further cure the solder resist ink so that the solder resist ink layer and the recessed resin plug form a stable interlocking structure, further improving the connection strength between the recessed resin plug and the first and second side oils of the board.

[0081] 2. Compared with traditional solder mask printing, the above-mentioned method for preparing solder mask for circuit boards based on plugging has better compatibility and can be applied to both plugging technology and vacuuming technology. On the one hand, it can reduce the standing time of solder mask ink, making the entire production process relatively compact and fast, that is, improving production efficiency. On the other hand, it avoids the trouble of switching between two different production lines, so as to quickly obtain a solder mask ink layer with good flatness, good appearance and strong connectivity. At the same time, since the via holes of the board body are plugged, the via holes of the board body can be better protected, which is especially suitable for the application of new energy vehicles in some harsh environments, thereby increasing the service life of the circuit board.

[0082] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as a restriction on the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing solder mask of a circuit board based on via plugging, characterized in that: The steps include: Providing a plate body, wherein the plate body is formed with a conducting hole; The via holes of the board body are plugged with a dual-cure resin to form a dual-cure resin column in the via holes of the board body; wherein the dual-cure resin is a mixture of dual-cure acrylic resin, dual-cure epoxy acrylic resin and dual-cure polyurethane acrylic resin; the usage ratio of the dual-cure acrylic resin: the dual-cure epoxy acrylic resin: the dual-cure polyurethane acrylic resin is 2:1:1; Performing a heat curing operation on the board body with the double-cured resin column to form a recessed resin plug in the via hole; wherein the heat curing operation is performed at a temperature of 90°C to 150°C and a time of 5min to 15min; making the surface of the recessed resin plug slightly sticky; performing a silk screen solder mask operation on the first side and the second side of the board body with the resin plug respectively; The board after the silk screen solder mask operation is vacuumed; wherein the vacuuming operation condition is 90kpa to 100kpa, and the time is 5 minutes to 10 minutes; Performing a light curing operation on the plate after the vacuum operation; wherein the light curing operation is performed under the condition of ultraviolet light irradiation for 3 minutes to 5 minutes; The board body after the light curing operation is baked.

2. The method for preparing solder mask of circuit board based on via plugging treatment according to claim 1, characterized in that: The step of baking the board after the light curing operation includes the following specific steps: The plate is tilted and placed in a 70°C to 75°C baking oven for baking for 25min to 55min.

3. The method for preparing solder mask of circuit board based on via plugging treatment according to claim 2, characterized in that: The inclination angle of the plate body is 1 degree to 5 degrees.

4. The method for preparing solder mask of circuit board based on via plugging treatment according to claim 1, characterized in that: Use 32T or 43T grid for silk screen solder mask operation.

5. The method for preparing solder mask of circuit board based on via plugging treatment according to claim 1, characterized in that: The aperture size of the via hole is 0.2 mm to 0.3 mm.

6. A circuit board, characterized in that: The circuit board is prepared by the method for preparing solder resist based on via plugging treatment according to any one of claims 1 to 5.

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