CN112911813B

CN112911813B - Manufacturing method for improving solder mask film print of PCB and prepared PCB

Info

Publication number: CN112911813B
Application number: CN202110103127.6A
Authority: CN
Inventors: 陈前; 康国庆; 肖安云; 王俊
Original assignee: Shenzhen Kinwong Electronic Co Ltd
Current assignee: Shenzhen Kinwong Electronic Co Ltd
Priority date: 2021-01-26
Filing date: 2021-01-26
Publication date: 2022-07-12
Anticipated expiration: 2041-01-26
Also published as: CN112911813A

Abstract

The application belongs to the technical field of electronic components, and particularly relates to a manufacturing method for improving a solder mask film print of a PCB (printed circuit board), namely a PCB jointed board deposited with a solder mask layer. The manufacturing method for improving the solder mask film print of the PCB comprises the following steps: providing a substrate, and designing a PCB jointed board on the substrate, wherein the substrate is at least provided with two PCB single boards, and the PCB single boards at least comprise one unit; arranging a gasket between adjacent units of the PCB single board to obtain a PCB jointed board paved with the gasket; and sequentially carrying out first resistance welding treatment and second resistance welding treatment on the PCB jointed board with the gasket, so as to obtain the PCB jointed board deposited with the resistance welding layer. According to the manufacturing method, the gaskets are arranged between the units, and meanwhile, twice resistance welding treatment is adopted, so that the height difference between the unit copper surface ink and the gap ink is effectively reduced, the problem of film printing caused by the height difference between the gap ink and the PCB single-board copper surface ink is solved, and the quality of the jointed board is improved.

Description

Manufacturing method for improving solder mask film print of PCB and prepared PCB

Technical Field

The application belongs to the technical field of electronic components, and particularly relates to a manufacturing method for improving a solder mask film print of a PCB (printed circuit board), in particular to a PCB deposited with a solder mask layer.

Background

During the solder mask process of manufacturing the circuit board, the circuit board and the exposure film are exposed and developed after being printed and pre-baked by ink, and in the exposure process, the exposure machine station exhausts air in the circuit board and the exposure film in a vacuumizing mode to enable the circuit board and the exposure film to be tightly attached. However, since the ink is only prebaked after printing, the unexposed ink can be washed away after exposure and development; therefore, the ink is not sufficiently cured after the prebaking. Under the condition that the solder resist ink is not fully cured and the height difference exists between the ink on the copper surface and the gap ink, a film print is formed on the surface of the circuit board, and the glossiness of the solder resist ink at the film print is poor, so that the overall appearance of the circuit board is influenced.

At present, for a circuit board which is easy to generate film prints, the following improvement schemes exist:

firstly, the prebaking time is prolonged by 3-5 minutes, but the scheme is an unconventional process, the manufacturing efficiency of the circuit board is affected, and the problem of incomplete development after exposure can be caused by excessive prebaking.

Secondly, a dispersed support layer is fixed above a non-functional area of the solder resist film, so that the exposed film can be effectively separated from a solder resist layer of a Printed Circuit Board (PCB), and obvious marks cannot be left on solder resist ink.

And thirdly, carrying out exposure treatment on the printed ink twice, wherein the vacuumizing range adopted by the first exposure is (350 +/-50) mm/hg, the vacuumizing range adopted by the second exposure is (720 +/-40) mm/hg, and the film printing is improved by adjusting the vacuumizing pressure of the two exposures.

Disclosure of Invention

The application aims to provide a manufacturing method for improving a solder mask film print of a PCB (printed circuit board), namely a PCB jointed board deposited with a solder mask layer, and aims to solve the problem that the existing circuit board is easy to generate the film print when exposed and affects the quality of the circuit board to a certain extent.

In order to achieve the purpose of the application, the technical scheme adopted by the application is as follows:

in a first aspect, the present application provides a manufacturing method for improving a solder mask film print of a PCB, comprising the following steps:

providing a substrate, and designing a PCB jointed board on the substrate, wherein the substrate is at least provided with two PCB single boards, and the PCB single boards at least comprise one unit;

arranging a gasket between adjacent units of the PCB single board to obtain a PCB jointed board paved with the gasket;

and sequentially carrying out first resistance welding treatment and second resistance welding treatment on the PCB jointed board with the gasket, so as to obtain the PCB jointed board deposited with the resistance welding layer.

Furthermore, the PCB single board comprises at least two units, and a gasket is arranged between the units in the PCB single board;

or, the PCB single board comprises at least two units and breaking frames, a gasket is arranged between the breaking frames of the adjacent PCB single boards, and a gasket is arranged between the units in the PCB single board.

Further, the step of providing a gasket includes: when the PCB jointed board is designed on the substrate, the position where the gasket needs to be arranged is reserved through the dry film, and the PCB jointed board with the gasket paved is obtained after etching.

Further, the cutting utilization rate of the substrate is 76% -85%.

Furthermore, the distance from the PCB single board to the edge of the substrate is more than or equal to 15 mm.

Further, the height of the gasket is the same as the height of the copper surface in the PCB single board.

Further, the shape of the gasket includes: circular and/or square.

Further, the distance between the gasket arranged between the adjacent PCB single plates and the PCB single plate is more than or equal to 0.2 mm;

the distance between the gasket arranged between the units in the PCB single board and the units is more than or equal to 0.2 mm.

Further, the first solder resist processing comprises the following steps:

and depositing a first layer of printing ink after carrying out first pre-printing treatment on the PCB jointed board with the gasket, and sequentially carrying out first pre-baking, first exposure and development treatment and first baking to obtain the PCB jointed board subjected to first solder resist treatment.

Further, the first prepress processing step includes: and (3) cleaning foreign matters on the surface of the PCB jointed board paved with the gasket by adopting acid washing, super-roughening and brushing, and roughening the surface of the board.

Further, the conditions for depositing the first layer of ink include: and printing a layer of ink with the thickness of 30-40 mu m by adopting a 36T-43T screen printing method.

Further, the conditions of the first prebaking include: prebaking for 50-70 min at the temperature of 65-75 ℃.

Further, the conditions of the first exposure development include: exposing the substrate under the conditions that the opening size of the exposure negative film is larger than the size of a copper surface required to be exposed on the substrate by one side by more than 0.025mm and the exposure energy is 300-500 mj, and developing by using a developing solution with the concentration of 0.5-1.5% at the temperature of 28-32 ℃.

Further, the conditions of the first baking include: baking for 60-120 min at 110-120 ℃.

Further, the second solder resist processing comprises the following steps:

and depositing a second layer of printing ink after the PCB jointed board subjected to the first solder mask treatment is subjected to the second pre-printing treatment, the second exposure and development treatment and the second baking in sequence to obtain the PCB jointed board deposited with the solder mask.

Further, the second pre-press treatment step includes: and (3) starting acid washing by using a volcanic ash grinding plate, removing foreign matters on the surface of the PCB jointed board subjected to the first resistance welding treatment, and making the surface rough.

Further, the conditions for depositing the second layer of ink include: printing a layer of printing ink with the thickness of 15-20 mu m by adopting a 46T-51T screen printing method.

Further, the conditions of the second prebaking include: prebaking for 50-70 min at the temperature of 65-75 ℃.

Further, the conditions of the second exposure development include: exposing the substrate under the conditions that the window size of the exposure negative film is larger than the size of the exposed copper surface on the substrate by one side by more than 0.05mm and the exposure energy is 300-500 mj, and developing by using a developing solution with the concentration of 0.5-1.5% at the temperature of 28-32 ℃.

Further, the conditions of the second baking include: and baking for 60-120 min at 125-135 ℃.

In a second aspect, the present application provides a PCB panel with a solder resist layer deposited thereon, which is prepared by the above method.

According to the manufacturing method for improving the PCB solder mask film print, the gasket is arranged at the gap position between the adjacent units of the PCB single plate, the amount of ink required to be filled when solder mask printing ink is reduced by arranging the gasket at the gap position, and the height difference between the unit copper surface ink and the ink at the gap position is reduced, so that the film print problem caused by the height difference between the gap position and the PCB single plate copper surface ink is improved. And then, carrying out solder mask treatment twice on the PCB jointed board with the gasket, wherein in the second solder mask treatment, because the first solder mask ink is completely cured after exposure, development and baking, under the condition that the height difference between the PCB single board unit copper surface ink and the gap ink is smaller, the external force borne by the PCB single board unit copper surface ink at the higher position is smaller, the film printing can be further improved, and thus the high-quality PCB jointed board deposited with the solder mask layer is prepared.

According to the PCB with the deposited solder mask, the manufacturing method for improving the solder mask film print of the PCB is adopted, so that the PCB is uniform in thickness of the solder mask layer, good in stability, free of film print and high in quality.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a PCB panel designed according to comparative example 1 of the present application;

FIG. 2 is a cross-sectional view of a PCB panel after solder mask treatment as provided in comparative example 1 of the present application;

FIG. 3 is a PCB panel designed according to example 1 of the present application;

FIG. 4 is a cross-sectional view of a PCB panel after solder mask treatment as provided in comparative example 2 of the present application;

FIG. 5 is a cross-sectional view of a PCB panel after solder mask treatment as provided in comparative example 3 of the present application;

FIG. 6 is a cross-sectional view of a PCB panel after solder mask treatment provided in example 1 of the present application;

the PCB comprises a substrate 1, a substrate 2, a PCB single board 3, a unit 4, a gasket 5, a breaking frame 6, a connecting position 7, a solder mask 7-1, a first solder mask 7-2 and a second solder mask.

Detailed Description

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly apparent, the present application is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

In the present invention, the term "and/or" describes the association relationship of the associated objects, and means that there may be three relationships, for example, a and/or B, which may mean: a is present alone, A and B are present simultaneously, and B is present alone. Wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.

In the present invention, "at least one" means one or more, "a plurality" means two or more. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, "at least one (one) of a, b, or c," or "at least one (one) of a, b, and c," may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, and c may be single or plural, respectively.

It should be understood that, in various embodiments of the present invention, the sequence numbers of the above-mentioned processes do not mean the execution sequence, some or all of the steps may be executed in parallel or executed sequentially, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The weight of the related components mentioned in the description of the embodiments of the present invention may not only refer to the specific content of each component, but also represent the proportional relationship of the weight among the components, and therefore, the content of the related components is scaled up or down within the scope disclosed in the description of the embodiments of the present invention as long as it is in accordance with the description of the embodiments of the present invention. Specifically, the mass in the description of the embodiments of the present invention may be a mass unit known in the chemical industry field such as μ g, mg, g, kg, etc.

The terms "first" and "second" are used for descriptive purposes only and are used for distinguishing purposes such as substances from one another, and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. For example, a first XX may also be referred to as a second XX, and similarly, a second XX may also be referred to as a first XX, without departing from the scope of embodiments of the invention. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

Based on this, a first aspect of the embodiments of the present application provides a manufacturing method for improving a solder mask film print of a PCB, including the following steps:

s10, providing a substrate 1, and designing a PCB jointed board on the substrate, wherein at least two PCB single boards 2 are arranged on the substrate 1, and each PCB single board 2 at least comprises one unit 3;

s20, arranging a gasket 4 between adjacent units 3 of the PCB single board 2 to obtain a PCB jointed board paved with the gasket;

and S30, sequentially carrying out first resistance welding treatment and second resistance welding treatment on the PCB jointed board with the gasket, so as to obtain the PCB jointed board deposited with the resistance welding layer.

According to the manufacturing method for improving the PCB solder mask film printing, the gasket 4 is arranged at the gap position between the adjacent units 3 of the PCB single plate 2, the gasket 4 is arranged at the gap position, the amount of ink required to be filled when the solder mask printing ink is reduced, and the height difference between the ink on the copper surface of the unit 3 and the ink on the gap position is reduced, so that the film printing problem caused by the height difference between the gap position and the ink on the copper surface of the PCB single plate 2 is improved. And then, carrying out twice resistance welding treatment on the PCB jointed board with the gasket, wherein in the second resistance welding treatment, because the first resistance welding ink is completely cured after exposure, development and baking, under the condition that the height difference between the copper surface ink of the unit 3 of the PCB single board 2 and the ink at the gap is smaller, the external force born by the copper surface ink of the unit 3 of the PCB single board 2 at a higher position is smaller, the film printing can be further improved, and thus the high-quality PCB jointed board with the deposited resistance welding layer 7 is prepared.

In the step S10, a PCB jointed board design is performed on the substrate, where at least two PCB boards 2 are disposed on the substrate 1, and each PCB board 2 at least includes one unit 3.

In some embodiments, the PCB board 2 includes at least two units 3, and in this case, in step S20, a spacer 4 needs to be disposed between the

units

3 and 3 in the PCB board 2. As shown in fig. 3.

In some embodiments, the PCB single board 2 includes the break frame 5 and at least two units 3 disposed in the break frame 5, in this case, in step S20, it is necessary to dispose the spacer 4 between the break frames 5 of the adjacent PCB single boards 2, and dispose the spacer 4 between the

units

3 and 3 in the PCB single board 2. As shown in fig. 3.

In some embodiments, as shown in fig. 1, a PCB panel design is performed on a substrate 1, two PCB boards 2 are provided, each PCB board 2 includes two units 3(PCS1 and PCS2), the units 3 are connected and fixed by a connection site 6, and due to consideration of symmetry and other factors when designing the panel, there may be a large gap between the units 3 and between the PCB boards 2. During solder mask printing, ink permeates the screen printing plate through the scraper and is uniformly printed on the copper surface of the PCB jointed board of the substrate 1, namely the ink discharging amount of each area of the circuit board is the same. However, as shown in fig. 1 and 2, in the PCB panel, the gaps between PCB single boards 2 and between unit 3PCS1 and unit 3PCS2 in PCB single board 2 are wider, and the amount of ink to be filled is larger, which results in too large difference between the ink level at the gaps and the ink level on the copper surface of unit 3 and broken edge 5 of PCB single board 2. After the printing ink is printed and prebaked, the printing ink is not completely cured and has soft texture, and when the film is exposed by an exposure machine, the film is extruded on the solder resist printing ink under the action of vacuum suction of the exposure machine and external force of glass. Because the height of the copper surface ink of the unit 3 and the broken edge 5 of the PCB single board 2 is larger than that of the ink at the gap, the external force borne by the copper surface ink of the unit 3 and the broken edge 5 of the PCB single board 2 is larger, and the softer solder resist ink is extruded. When the height difference A1 of the position of the printing ink is smaller, the height difference between the copper surfaces of the unit 3 and the broken edge 5 of the PCB single plate 2 and the printing ink surface at the gap is small, the printing ink stress of the copper surfaces is small during film treatment, namely all the printing ink bear external force together, the external force of the contact between the printing ink of the copper surfaces of the unit 3 and the broken edge 5 of the PCB single plate 2 and the film is reduced, and the film printing is not obvious at the moment. When the height difference a1 between the ink on the copper plate of the unit 3 and the broken edge 5 of the PCB single board 2 and the ink at the gap is large, the external force applied to the ink on the copper surface of the unit 3 and the broken edge 5 of the PCB single board 2 is large, and the film print is easily generated on the ink on the copper surface of the unit 3 and the broken edge 5 of the PCB single board 2.

The more the number of the PCB single boards 2 of the base board 1 with the same size and the imposition design is, the higher the utilization rate is. Generally, in order to improve the utilization rate, the board manufacturer should increase the size of the substrate 1 as much as possible and arrange as many PCB boards 2 on the substrate 1 as possible. However, in the manufacturing process, the substrate 1 is too large in size, so that the copper plating is liable to be uneven, the copper thickness is liable to be very different, and the board surface is liable to warp. The great difference of copper thickness and board warpage can cause the height of the printed ink surface of the board surface to be inconsistent during solder mask printing, and in the area with the large relative height difference of the ink surface, the film printing is easily generated after the solder mask film is used for exposure and development after the ink is pre-baked. The substrate 1 is too small in size, so that the utilization rate of a plate material is influenced, and the production cost of a factory is indirectly increased.

In some embodiments, the open material utilization rate of the substrate 1 is 76% to 85%. In some embodiments, the distance from the PCB single board 2 to the board edge of the substrate 1 is more than or equal to 15 mm.

According to the embodiment of the application, the cutting utilization rate of the substrate 1 is 76-85%, the size of the substrate 1 is properly reduced on the premise that the cutting utilization rate of the substrate 1 is more than or equal to 76% and less than or equal to 85%, the distance from the PCB single board 2 to the edge of the substrate 1 is increased, and correspondingly, the number of the PCB single boards 2 on the substrate 1 is reduced. The small size of the substrate 1 and the increased distance between the edges of the board result in a reduction in the cutting efficiency, but the non-uniformity of the printing ink due to the non-uniform thickness of the copper plating can be improved, thereby reducing the problem of the film printing. In addition, the embodiment of the present application requires that the board edge distance C from the PCB single board 2 to the substrate 1 is greater than or equal to 15mm, as shown in fig. 3, so as to reduce as much board edge glue flow to cause uneven board thickness in the unit 3, and further cause uneven printing ink.

In some embodiments, in step S20, the height of the spacer 4 is the same as the height of the copper surface of the unit 3 or the break frame 5 in the PCB single board 2, so that uneven stress on the copper surface due to inconsistent height can be effectively avoided, and the problem of film printing caused by a large difference between the height of the ink on the copper surface and the height of the ink at the gap can be avoided.

In some embodiments, in step S20, the step of arranging the spacer 4 at the gap position between the adjacent PCB boards 2 and the gap position between the unit 3 and the unit 3 in the PCB board 2 includes: when the PCB jointed board is designed on the substrate 1, the position where the gasket 4 needs to be arranged is reserved through the dry film, and the copper gasket 4 is formed at the reserved position after etching, so that the PCB jointed board with the gasket is obtained. When the PCB jointed board design is carried out on the substrate 1, the position of the gasket 4 needs to be set is reserved through the dry film, and when the circuit board is etched, the copper gasket 4 is formed due to dry film protection when the pattern circuit in the circuit board unit 3 is formed through etching. By the method, the copper gasket 4 can be directly formed at the gap without adding an additional setting process or flow; and the height of the copper gasket 4 is completely consistent with the height of the copper surface of the unit 3 or the break frame 5 in the PCB single board 2, so that the height of the copper gasket at the gap is effectively ensured, and the uneven stress of the copper surface caused by the inconsistent height is avoided.

In some embodiments, the shape of the shim 4 includes: round and/or square, but other shapes are also possible.

In some embodiments, the distance between the gasket 4 disposed between the adjacent PCB single boards 2 and the PCB single board 2 is greater than or equal to 0.2 mm. In some embodiments, the distance between the unit 3 and the spacer 4 arranged between the unit 3 and the unit 3 in the PCB single board 2 is more than or equal to 0.2 mm. In the embodiment of the application, the distance between the gasket 4 and the PCB single board 2 or the unit 3 is not less than 0.2mm, and enough routing distance is reserved, so that in the subsequent process, routing can be performed in the gap between the PCB single board 2 and the gap between the unit 3 in the PCB single board 2, and thus the single PCB single board 2 or the single PCB unit 3 can be obtained.

In some embodiments, as shown in fig. 3, in the embodiments of the present application, two PCB boards 2 are disposed on a substrate 1, each PCB board 2 includes two units 3(PCS), the units 3 are connected by a connection site 6, and copper is laid at a gap between the PCB boards 2 and a gap between the units 3 in the PCB board 2 by using a gasket 4. As shown in fig. 4, after the spacer 4 is arranged at the gap position, the height difference a2 of the position where the solder resist ink is located is small, that is, all the ink bears the external force together, the external force of the contact between the ink on the copper surface of the unit 3 of the PCB single board 2 and the film is reduced, and the film printing is not obvious.

In some embodiments, in step S30, the first solder resist process includes the steps of:

and S31, after the PCB jointed board with the gasket is subjected to first pre-printing treatment, depositing a first layer of printing ink, and sequentially carrying out first pre-baking, first exposure and development treatment and first baking to obtain the PCB jointed board subjected to first solder resist treatment. According to the embodiment of the application, pretreatment, ink deposition, pre-baking, exposure development and baking are sequentially carried out on the PCB jointed board with the gasket, so that first-time resistance welding treatment is completed, and a first solder mask layer 7-1 is formed on the PCB jointed board.

In some embodiments, the step of first pre-press processing comprises: and cleaning foreign matters on the surface of the PCB jointed board with the gasket by acid washing, super-roughening and brushing, and roughening the board surface to increase the bonding force between the copper surface and the solder resist ink so as to obtain the PCB jointed board with the rough board surface.

In some embodiments, the step of depositing the first layer of ink comprises: a layer of thick ink with the thickness of 30-40 mu m is printed on the surface of the PCB jointed board with the rough board surface by adopting a 36T-43T screen printing plate, so that the height difference between the ink at the gap and the ink on the copper surface in the unit 3 is reduced as much as possible. In some embodiments, the screen is made by interweaving different screen meshes, T represents the screen mesh number, the higher the T number, the denser the screen mesh number, the less ink is easy to permeate the screen into the plate surface, the thinner the ink thickness printed on the plate surface is, the more uniform the ink is, the first 36T-43T screen is adopted, a thicker layer of ink can be printed on the plate surface, and the difference between the ink height at the gap and the ink height of the copper surface of the unit 3 is reduced as much as possible.

In some embodiments, the conditions of the first prebake comprise: and prebaking for 50-70 min by adopting ways of tunnel oven and the like under the condition that the temperature is 65-75 ℃, so that the printing ink is slightly cured but not completely cured, the texture is soft, and the subsequent exposure and development are facilitated.

In some embodiments, the conditions for the first exposure development include: exposing the exposed negative film under the conditions that the window size of the exposed negative film is larger than the size of the exposed copper surface on the substrate by one side by more than 0.025mm and the exposure energy is 300-500 mj, and developing by using a liquid medicine such as sodium carbonate or potassium carbonate with the concentration of 0.5-1.5% under the condition that the temperature is 28-32 ℃.

In some embodiments, the conditions of the first bake include: and baking for 60-120 min at 110-120 ℃ to enable the solder resist ink to be basically cured and molded, and forming a stable first solder resist layer 7-1 on the PCB jointed board.

In the embodiment of the application, when the solder mask is processed for the first time, because the height difference between the ink at the gap and the ink on the copper surface of the unit 3 is large, a serious film print can be generated. Therefore, the embodiment of the application performs the second solder mask treatment on the basis of the first solder mask treatment.

In some embodiments, in step S30, the second solder resist processing includes:

s50, after the PCB jointed board subjected to the first solder mask treatment is subjected to second printing pretreatment, depositing a second layer of printing ink, and sequentially carrying out second pre-baking, second exposure and development treatment and second baking to form a second solder mask layer 7-2 on the surface of the first solder mask layer 7-1, so as to obtain the PCB jointed board deposited with the assembly welding layer 7. The embodiment of the application performs the resistance welding treatment for the second time, and when performing the resistance welding treatment for the second time, because the first-time resistance welding ink is completely cured after exposure, development and baking, under the condition that the height difference between the copper surface ink of the unit 2 and the copper surface ink of the unit 3 of the PCB single board and the surface ink of the spacer 4 at the gap is smaller, the external force borne by the copper surface ink of the unit 3 of the unit 2 of the PCB single board at the higher position is smaller, the film printing can be further improved, and thus the high-quality PCB jointed board deposited with the solder mask layer 7 is manufactured.

In some embodiments, the step of second pre-press treatment comprises: and (3) adopting a volcanic ash grinding plate, starting acid washing, removing foreign matters on the first solder mask layer 7-1 on the surface of the jointed PCB board, and roughening the surface of the jointed PCB board. In the embodiment of the application, the second pretreatment is carried out on the solidified first solder mask layer 7-1 board surface, in order to prevent the attack of super-coarsening liquid medicine on the solder mask layer, volcanic ash is adopted to grind the board, acid washing is started, foreign matters on the surface of the PCB jointed board subjected to the first solder mask treatment are removed, the board surface is rough, and the binding force between the first solder mask layer 7-1 ink and the second solder mask layer 7-2 ink is increased.

In some embodiments, the conditions for depositing the second layer of ink comprise: printing a layer of printing ink with the thickness of 15-20 mu m by adopting a 46T-51T screen printing method. According to the embodiment of the application, 46T-51T screen printing is adopted in the second printing, so that the second layer of printing ink can be uniformly covered and has uniform thickness, the film prints generated by the first solder mask treatment can be covered, and the printing ink thickness can be ensured not to be too thick and exceed the design requirements of customers, and the subsequent assembly is influenced.

In some embodiments, the conditions of the second prebake comprise: and prebaking for 50-70 min at 65-75 ℃ to slightly cure the printing ink, but not completely cure the printing ink, so that the printing ink is soft in texture and beneficial to subsequent exposure and development.

In some embodiments, the conditions for the second exposure development include: exposing the exposed negative film under the conditions that the window size of the exposed negative film is larger than the size of the exposed copper surface on the substrate by one side by more than 0.05mm and the exposure energy is 300-500 mj, and developing by using a liquid medicine such as sodium carbonate or potassium carbonate with the concentration of 0.5-1.5% under the condition that the temperature is 28-32 ℃. In the second exposure and development of the embodiment of the application, the unilateral compensation of 0.05mm is adopted for compensating the exposure alignment deviation, and if the compensation of the second exposure is consistent with the compensation amount of the first exposure, the pad is easily covered by the ink due to deviation after the second exposure.

In some embodiments, the conditions of the second bake include: and baking for 60-120 min at 125-135 ℃ to fully cure the printing ink, and forming a second solder mask layer 7-2 on the surface of the first solder mask layer 7-1 to obtain the PCB jointed board deposited with the solder mask layer 7 without film printing.

In a second aspect of the embodiments of the present application, a PCB panel deposited with a solder resist layer is prepared by the above method.

According to the PCB deposited with the solder mask layer 7, the manufacturing method for improving the solder mask film printing of the PCB is adopted, so that the thickness of the solder mask layer 7 on the PCB is uniform, the stability is good, no film printing exists, and the quality is high.

In order to make the above implementation details and operations of the present application clearly understood by those skilled in the art, and obviously show the improvement performance of the manufacturing method of the solder mask film for the PCB board according to the embodiments of the present application, the above technical solution is exemplified by a plurality of embodiments below.

Example 1

A manufacturing method for improving solder mask film printing of a PCB comprises the following steps:

1. providing a substrate 1, reserving a position needing to be provided with a gasket 4 through a dry film when designing the PCB jointed board on the substrate 1, and obtaining the PCB jointed board with the gasket after etching. The PCB single board 2 comprises PCS units 3 which are mutually connected, the cutting utilization rate is 76%, the distance from the PCB single board 2 to the board edge of the substrate 1 is 15mm, the short side size of the PCB single board 2 is 400mm, and the long side size of the PCB single board 2 is 500 mm. The distance B1 between the gasket 4 arranged between the adjacent PCB single boards 2 and the adjacent PCB single board 2 is 0.2 mm; the spacer 4 disposed between the unit 3 and the unit 3 in the PCB single board 2 has a spacing B2 of 0.2mm from the adjacent unit 3. As shown in fig. 3.

2. Sequentially carrying out first resistance welding treatment and second resistance welding treatment on the PCB jointed board with the gasket, and sequentially forming a first welding layer set 7-1 and a second welding layer set 7-2; wherein the first solder resist treatment comprises the following steps:

firstly, pickling and super-roughening the jointed PCB board with the gasket, and brushing to remove foreign matters on the surface of the jointed PCB board with the gasket, so that the board surface is rough;

secondly, printing a layer of ink with the thickness of 30 mu m by adopting a 43T screen printing plate, so that the ink fills the gap, and the height difference between the ink on the copper surface and the ink at the gap position is reduced;

thirdly, prebaking for 60min at the temperature of 70 ℃;

fourthly, after exposure is carried out under the conditions that the window size of an exposure negative film is 0.025mm larger than the size of a single side of a copper surface required to be exposed on a substrate and the exposure energy is 400mj, developing is carried out by using sodium carbonate liquid medicine with the concentration of 1% under the condition that the temperature is 28 ℃;

and fifthly, baking for 60min at the temperature of 120 ℃ to obtain the PCB jointed board subjected to the first solder mask treatment.

The second solder resist treatment comprises the following steps:

sixthly, grinding the PCB jointed board with the gasket by volcanic ash, starting acid washing, removing foreign matters on the surface of the PCB jointed board subjected to the first resistance welding treatment, and roughening the board surface;

seventhly, printing a layer of printing ink with the thickness of 15 mu m by adopting a 51T screen printing plate to fill the gap with the printing ink, and further reducing the height difference between the printing ink on the copper surface and the printing ink at the gap position;

eighthly, prebaking for 60min at the temperature of 70 ℃;

ninthly, adopting a film exposure with the window size of the exposure negative film being 0.025mm larger than the single side of the film window after the first printing, namely, developing by using a sodium carbonate solution with the concentration of 1% under the condition that the window size of the exposure negative film is 0.05mm larger than the single side of the copper surface required to be exposed on the substrate and the exposure energy is 500mj after the exposure;

baking at 135 deg.C for 60min to obtain PCB jointed board with solder mask layer 7 deposited. As shown in fig. 6.

Comparative example 1

Comparative example 1 differs from example 1 in that:

step 1, when the PCB jointed board is designed on the substrate 1, the position of a gasket is not reserved, and the PCB jointed board is obtained by direct etching, as shown in attached figure 1.

And 2, performing one-time solder resisting treatment on the PCB jointed board to obtain the PCB jointed board deposited with the solder resisting layer 7. As shown in fig. 2.

Comparative example 2

Comparative example 1 differs from example 1 in that:

and 2, performing one-time solder mask treatment on the PCB jointed board to obtain the PCB jointed board deposited with the solder mask layer 7. As shown in fig. 4.

Comparative example 3

Comparative example 1 differs from example 1 in that:

And 2, performing solder mask treatment on the PCB jointed board twice to obtain the PCB jointed board deposited with the solder mask layers 7-1 and 7-2. As shown in fig. 5.

Further, in order to verify the improvement of the manufacturing method of the solder mask film of the PCB in the embodiment of the present application, the height difference a of the ink at the copper surface and the gap of the PCB single board 2 in the embodiment 1 and the comparative examples 1 to 3 is measured for a plurality of times, and the test result interval of the height difference a of each embodiment and comparative example is shown in the following table 1:

TABLE 1

	Height difference/. mu.m
		Comparative example 1A 1	38-42
Comparative example 2A 2	22-26
		Comparative example 3A 3	18-22
Example 1A 4	12-16

From the test results, in the embodiment 1 of the present application, by spreading copper at the gap and performing the solder mask treatment twice, compared with the comparative example 1 in which copper is not spread and solder mask treatment is not performed twice, the comparative example 2 in which copper is spread but solder mask treatment is performed only once, and the comparative example 3 in which copper is not spread and solder mask treatment is performed twice, the height difference between the copper surface and the ink at the gap is significantly reduced, and thus the occurrence of film printing in the solder mask treatment is effectively improved.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A manufacturing method for improving PCB solder mask film is characterized by comprising the following steps:

providing a substrate, and designing a PCB jointed board on the substrate, wherein at least two PCB single boards are arranged on the substrate;

sequentially carrying out first resistance welding treatment and second resistance welding treatment on the PCB jointed board with the gasket to obtain the PCB jointed board deposited with the resistance welding layer;

the PCB single board comprises at least two units, the units are connected and fixed through connecting positions, and a gasket is arranged between the units in the PCB single board;

or, the PCB single board includes a break frame and at least two units disposed in the break frame, a gasket is disposed between the break frames of adjacent PCB single boards, and a gasket is disposed between the units in the PCB single board;

the distance between the gasket arranged between the adjacent PCB single plates and the PCB single plate is more than or equal to 0.2 mm;

the distance between the gasket arranged between the units in the PCB single board and the units is more than or equal to 0.2 mm;

the step of providing a gasket comprises: when the PCB jointed board is designed on the substrate, the position where the gasket needs to be arranged is reserved through the dry film, and the copper gasket is formed at the reserved position after etching, so that the PCB jointed board with the gasket is obtained.

2. The manufacturing method for improving the solder mask film print of the PCB as recited in claim 1, wherein the cutting utilization rate of the substrate is 76% -85%;

and/or the distance from the PCB single board to the board edge of the substrate is more than or equal to 15 mm;

and/or the height of the gasket is the same as that of the copper surface in the PCB single board;

and/or, the shape of the gasket comprises: circular and/or square.

3. The manufacturing method for improving the solder mask film of the PCB as claimed in claim 1, wherein the first solder mask process comprises the steps of:

and depositing a first layer of printing ink after the first pre-printing treatment is carried out on the PCB jointed board with the gasket, and sequentially carrying out first pre-baking, first exposure and development treatment and first baking to obtain the PCB jointed board subjected to the first solder mask treatment.

4. The manufacturing method for improving the solder mask film of the PCB as recited in claim 3, wherein the step of pre-processing the first printing comprises: cleaning foreign matters on the surface of the PCB jointed board paved with the gasket by adopting acid washing and super-roughening, and brushing to roughen the board surface;

and/or, the conditions for depositing the first layer of ink comprise: printing a layer of printing ink with the thickness of 30-40 mu m by adopting a 36T-43T screen printing plate;

and/or the conditions of the first prebaking comprise: prebaking for 50-70 min at 65-75 ℃;

and/or, the conditions of the first exposure development comprise: exposing the substrate under the conditions that the window size of the exposure negative film is larger than the size of the exposed copper surface on the substrate by one side by more than 0.025mm and the exposure energy is 300-500 mj, and developing by using a developing solution with the concentration of 0.5-1.5% at the temperature of 28-32 ℃;

and/or, the conditions of the first baking comprise: baking for 60-120 min at 110-120 ℃.

5. The manufacturing method for improving the solder mask film of the PCB as recited in claim 4, wherein the second solder mask process comprises the steps of:

6. The manufacturing method for improving the solder mask film of the PCB as recited in claim 5, wherein the step of the second pre-printing treatment comprises: starting acid washing by using a volcanic ash grinding plate, and removing foreign matters on the surface of the PCB jointed board subjected to the first resistance welding treatment to make the surface rough;

and/or, the conditions for depositing the second layer of ink comprise: printing a layer of printing ink with the thickness of 15-20 mu m by adopting a 46T-51T screen printing plate;

and/or the conditions of the second prebaking comprise: prebaking for 50-70 min at 65-75 ℃;

and/or, the conditions of the second exposure development comprise: exposing the substrate under the conditions that the window size of the exposure negative film is larger than the size of the exposed copper surface on the substrate by one side by more than 0.05mm and the exposure energy is 300-500 mj, and developing by using a developing solution with the concentration of 0.5-1.5% at the temperature of 28-32 ℃;

and/or, the conditions of the second baking comprise: baking for 60-120 min at 125-135 ℃.

7. A PCB jointed board deposited with a solder mask layer, which is prepared by the method as claimed in any one of claims 1 to 6.