A processing method for a circuit board and a circuit board

Abstract

The present application discloses a processing method of a circuit board and a circuit board, wherein the processing method of the circuit board includes: drilling a hole in the circuit board to form a positioning hole on the circuit board, and then copper deposition, electroplating, and pattern production are performed on the circuit board in sequence; forming a solder resist ink layer on the circuit board after pattern production, and filling the positioning hole with the solder resist ink layer; pasting an exposure film with a non-light-blocking area having a set pattern facing the positioning hole on the solder resist ink layer to expose the solder resist ink layer; wherein the set pattern is located within the projection of the positioning hole on one side of the exposure film; developing the exposed solder resist ink layer, and performing laser hole burning on the developed circuit board facing the positioning hole to remove the solder resist ink in the positioning hole. Through the above-mentioned method, the present application can effectively remove the solder resist ink at the edge of the circuit board corresponding to the positioning hole, thereby effectively improving the quality of the final finished circuit board and the yield rate of the product.

Description

Technical Field

[0001] The present application relates to the technical field of circuit board processing, and in particular to a circuit board processing method and a circuit board. Background Art

[0002] Due to the high flatness requirements of the packaging substrate, a flattening process is usually required during the solder mask processing. During this process, while the solder mask ink is leveled by heat and pressure, the positioning holes distributed around the packaging substrate will be filled and blocked by the solder mask ink. During development, the ink in the positioning holes is thick and difficult to develop cleanly, so the residual ink blocks need to be burned off by laser drilling.

[0003] However, the residual ink blocks are easily flipped up and adhered to the edges of the positioning holes on the circuit board due to the unbalanced effect of the developer spray pressure on both sides of the product, so that the laser cannot burn the holes and the ink blocks remain in the circuit board product, resulting in quality abnormalities or even the entire circuit board being scrapped, which has a great impact on the product's yield rate. Summary of the invention

[0004] The present application provides a circuit board processing method and a circuit board to solve the problem that the circuit board processing method in the prior art will inevitably leave residual solder mask ink at the edges corresponding to the positioning holes on the circuit board and cannot be removed, thereby causing quality abnormalities and even making the entire circuit board scrapped, which has a significant impact on the product yield.

[0005] In order to solve the above technical problems, a technical solution adopted in the present application is: to provide a method for processing a circuit board, wherein the method for processing the circuit board includes: drilling a hole in the circuit board to form a positioning hole on the circuit board, and then copper plating, electroplating and patterning the circuit board in sequence; forming a solder resist ink layer on the circuit board after patterning, and filling the positioning hole with the solder resist ink layer; attaching an exposure film having a non-light-blocking area with a set pattern facing the positioning hole on the solder resist ink layer to expose the solder resist ink layer; wherein the set pattern is located within the projection of the positioning hole on one side of the exposure film; developing the exposed solder resist ink layer, and performing laser burning on the developed circuit board facing the positioning hole to remove the solder resist ink in the positioning hole.

[0006] The set pattern includes a first pattern portion, the first pattern portion and the positioning hole have the same pattern style, and the projections of the first pattern portion and the positioning hole on one side of the exposure film have the same geometric center.

[0007] The set pattern further includes a plurality of second pattern portions, and the plurality of second pattern portions all extend from the outer edge of the first pattern portion in a direction away from the geometric center of the first pattern portion with a set width.

[0008] The width is set to 0.08-0.12 mm, and the minimum distance between the second pattern portion and the inner wall of the positioning hole is 10-15 μm.

[0009] The included angles formed by the central axes of every two adjacent second pattern portions and the geometric centers of the first pattern portions are the same.

[0010] The positioning hole is a circular hole, the first pattern portion is a concentric circle of the projection of the positioning hole on one side of the exposure film, and the diameter of the first pattern portion is 80% of the cross-sectional diameter of the positioning hole.

[0011] The number of the second pattern parts is 4, and the angle formed by every two adjacent second pattern parts and the center of the first pattern part is a right angle.

[0012] Among them, the positioning hole is a straight-sided elliptical hole, the first pattern portion is a straight-sided ellipse, and the number of the second pattern portions is 8.

[0013] Among them, after drilling the circuit board to form positioning holes on the circuit board, after copper deposition, electroplating and pattern making steps are performed on the circuit board in sequence, before the step of forming a solder resist ink layer on the circuit board after pattern making and filling the positioning holes with the solder resist ink layer, it also includes: performing solder resist pre-treatment on the circuit board after pattern making to remove debris on the opposite two sides of the circuit board; the step of forming a solder resist ink layer on the circuit board after pattern making and filling the positioning holes with the solder resist ink layer includes: performing solder resist coating and solder resist flattening on the circuit board after the solder resist pre-treatment to form a solder resist ink layer on the opposite two sides of the circuit board, and filling the positioning holes with the solder resist ink layer.

[0014] In order to solve the above technical problems, another technical solution adopted in the present application is: to provide a circuit board, wherein the circuit board is obtained by the processing method of the circuit board as described in any of the above items.

[0015] The beneficial effect of the present application is as follows: different from the prior art, the processing method of the circuit board in the present application forms positioning holes on the circuit board, and then forms a solder resist ink layer on the circuit board, and after the solder resist ink layer fills the positioning holes, an exposure film with a non-light-blocking area having a set pattern opposite to the positioning holes is attached to the solder resist ink layer to expose the solder resist ink layer, thereby effectively preventing part of the solder resist ink in the positioning holes from sticking to the edges of the circuit board corresponding to the positioning holes when the exposed solder resist ink layer is developed, thereby enabling the developed circuit board to be laser burned opposite to the positioning holes to remove the solder resist ink in the positioning holes, thereby effectively improving the quality of the final finished circuit board and the yield rate of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0017] Figure 1a It is a flow chart of the first embodiment of the method for manufacturing an embedded component circuit board of the present application;

[0018] Figure 1b-Figure 1i yes Figure 1a A schematic flow chart of an implementation method corresponding to S11-S14;

[0019] Figure 2 It is a flow chart of the second embodiment of the method for manufacturing an embedded component circuit board of the present application. DETAILED DESCRIPTION

[0020] In order to make the technical problems solved by the present application, the technical solutions adopted and the technical effects achieved more clearly, the technical solutions of the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0021] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0022] Please refer to FIG. 1 , which is a schematic flow chart of a first embodiment of a method for processing a circuit board of the present application. This embodiment includes the following steps:

[0023] S11: After drilling holes on the circuit board to form positioning holes on the circuit board, copper deposition, electroplating and patterning are sequentially performed on the circuit board.

[0024] Specifically, Figure 1b As shown, in the manufacturing process of the circuit board, it is usually inevitable to drill holes in it. For example, interlayer conductive holes are made in the core board 100 by mechanical drilling or laser drilling to realize the set circuit logic. At the same time, it is usually necessary to drill positioning holes 101 of the packaging substrate to facilitate subsequent shape milling and customer positioning.

[0025] Furthermore, after forming the interlayer conductive holes and positioning holes 101 in the core board 100 of the circuit board, the circuit board needs to be copper plated, electroplated and patterned in sequence to form a corresponding patterned conductive layer 110 in the circuit board, so as to realize the pre-designed circuit logic.

[0026] It is understandable that the core board 100 specifically refers to a circuit functional unit in a circuit board, such as a single-layer copper clad laminate; or a multi-layer copper clad laminate, and a semi-cured sheet is stacked between each two adjacent layers of the multi-layer copper clad laminate.

[0027] S12: forming a solder resist ink layer on the circuit board after patterning, and filling the positioning holes with the solder resist ink layer.

[0028] Specifically, Figure 1c As shown, in order to protect the outermost conductive layer 110 of the circuit board, after the pattern production of the circuit board is completed, it is usually necessary to further apply solder resist ink on the conductive layers 110 on opposite sides of the circuit board to form solder resist ink layers 120. In order to ensure the flatness of the circuit board, it is also necessary to flatten the solder resist ink applied on the conductive layer 110, for example, by increasing the fluidity of the solder resist ink by heating and applying mechanical pressure to it by a high-flatness steel plate, so that the solder resist ink with uneven surfaces applied on the opposite sides of the circuit board is leveled, and in the process, the positioning holes 101 that were not originally filled with solder resist ink are also filled with flowing solder resist ink, that is, the finally formed solder resist ink layer 120 is filled in the positioning holes 101.

[0029] Optionally, the thickness of the solder resist ink layer 120 corresponding to the portion disposed on the conductive layer 110 is 10-40 μm, and the thickness of the portion corresponding to the portion filled in the positioning hole 101 is 100-500 μm.

[0030] S13: attaching an exposure film having a non-light-blocking area with a set pattern facing the positioning hole onto the solder resist ink layer to expose the solder resist ink layer.

[0031] Furthermore, if Figure 1d As shown, a specially designed exposure film with light blocking spots is attached to the solder resist ink layer 120 to expose the solder resist ink layer 120. For example, a UV (ultraviolet) light is irradiated onto the solder resist ink layer 120 with the exposure film attached to expose the solder resist ink layer 120.

[0032] It can be understood that when the solder resist ink is irradiated by UV light, the resin monomer in the solder resist ink will produce free radical collisions and break double bonds, resulting in a polymerization cross-linking reaction, thereby generating a high molecular polymer that is insoluble in the developer solution. The solder resist ink at the position of the light blocking point of the exposure film is shielded by the light blocking point of the exposure film during the exposure process, thereby avoiding the polymerization cross-linking reaction. That is, the solder resist ink here can be dissolved in the developer solution during the subsequent development process, and can be removed.

[0033] Among them, the area in the exposure film where the light-blocking points are set is the light-blocking area, and the area where the light-blocking points are not set is the non-light-blocking area. In this embodiment, the non-light-blocking area of ​​the exposure film attached to the solder resist ink layer 120 has a setting pattern 14 facing the positioning hole 101, and the setting pattern 14 is located within the projection of the positioning hole 101 on one side of the exposure film, so that after the solder resist ink layer 120 is exposed, the unblocked part of the solder resist ink layer 120 can be converted into a polymer layer 130, and the cross-section of the part of the polymer layer 130 located in the positioning hole 101 is the setting pattern 14.

[0034] Alternatively, if Figure 1e As shown, Figure 1e Specifically, it is a schematic diagram of a top view of a partial area of ​​the exposure film attached to the solder resist ink layer 120 corresponding to the positioning hole 101. The setting pattern 14 specifically includes a first pattern portion 141. The first pattern portion 141 has the same pattern style as the positioning hole 101, and the projections of the first pattern portion 141 and the positioning hole 101 on one side of the exposure film have the same geometric center, for example, both are circular and concentric circles. It can be understood that the high molecular polymer layer 130 located in the positioning hole 101 corresponding to the first pattern portion 141 is a cylinder.

[0035] Optionally, the set pattern 14 further includes a plurality of second pattern portions 142 , and the plurality of second pattern portions 142 are all extended from the outer edge of the first pattern portion 141 in a direction away from the geometric center of the first pattern portion 141 with a set width.

[0036] Alternatively, if Figure 1f As shown, Figure 1f yes Figure 1e The enlarged structural diagram corresponding to the A area in FIG. 1 is a schematic diagram of a second pattern portion 142 , wherein the set width L1 of each of the second pattern portions 142 is 0.08-0.12 mm.

[0037] Optionally, a minimum distance L2 between the second pattern portion 142 and the inner wall of the positioning hole 101 is 10-15 microns.

[0038] Furthermore, the included angles formed by the central axes of every two adjacent second pattern portions 142 and the geometric center of the first pattern portion 141 are the same, that is, the plurality of second pattern portions 142 are evenly distributed on the outer edge of the first pattern portion 141 .

[0039] In a specific embodiment, the positioning hole 101 is a circular hole, the first pattern portion 141 is a concentric circle of the projection of the positioning hole 101 on one side of the exposure film, and the diameter D2 of the first pattern portion 141 is 80% of the cross-sectional diameter D1 of the positioning hole 101 .

[0040] Furthermore, the number of the second pattern portions 142 is four, and the angle formed by the center of each two adjacent second pattern portions 142 and the first pattern portion 141 is a right angle.

[0041] In a specific embodiment, Figure 1g As shown, Figure 1g Specifically, it is a schematic diagram of the top view of the structure of a partial area of ​​another exposure film attached to the solder mask ink layer 120 corresponding to the positioning hole 101, and the positioning hole 101 is specifically a straight-edged elliptical hole, that is, a runway-shaped hole, and the first pattern portion 141 is also a straight-edged elliptical hole, and the number of the second pattern portions 142 is 8, and they are evenly distributed on the outer edge of the first pattern portion 141.

[0042] Furthermore, the outer edge of the first pattern portion 141 is parallel to the edge of the positioning hole 101 and the spacing L1 therebetween is 20% of the distance from the center axis of the positioning hole 101 to its edge, or 20% of the radius of the two corresponding semicircles.

[0043] in, Figure 1g The enlarged structural diagram corresponding to area B is the same as Figure 1f , and the corresponding data parameters are the same as Figure 1f For the corresponding text content, please refer to Figure 1f And the related text description will not be repeated here.

[0044] It is understandable that in other embodiments, the positioning hole 101 may also be any other reasonable pattern style, and the corresponding first pattern portion 141 may also be any other reasonable pattern style, and the present application does not limit this.

[0045] S14: Developing the exposed solder resist ink layer, and performing laser hole burning on the developed circuit board facing the positioning hole to remove the solder resist ink in the positioning hole.

[0046] Specifically, Figure 1hAs shown, the solder resist ink layer 120 after exposure is developed, for example, the corresponding circuit board is immersed in a developer solution to dissolve the unexposed portion of the solder resist ink layer 120, thereby removing the solder resist ink at the light blocking point position in the solder resist ink layer 120 that is opposite to the exposure film, so as to expose a portion of the conductive layer 110 on one end surface of the circuit board to facilitate welding in subsequent process steps.

[0047] It is understandable that during this development process, since the solder resist ink layer 120 in the positioning hole 101 corresponds to the area of ​​the set pattern 14 as a non-light blocking area, a polymerization and cross-linking reaction has occurred during exposure to form a high molecular polymer layer 130, and therefore it cannot be dissolved and removed. The solder resist ink layer 120 located in the positioning hole 101 has a thickness comparable to that of the core board 100, usually reaching 100-500μm. During development, due to the need to control the solder resist side erosion, over-development is not allowed. Only a portion of the unexposed solder resist ink located in the positioning hole 101 can be developed away, and the remaining portion of the ink adheres to the middle position of the inner wall of the positioning hole 101, and cooperates and connects with the exposed portion of the polymer layer 130 in the positioning hole 101 corresponding to the second set pattern 14, so that the polymer layer 130 in the positioning hole 101 is effectively adhered to the inner wall of the positioning hole 101, and cannot break through and adhere back to the conductive layer 110 or the edge of the core board 100 close to the positioning hole 101.

[0048] Furthermore, after developing the exposed solder resist ink layer 120, laser hole burning is performed on the developed circuit board facing the positioning hole 101 in the circuit board. For example, a laser drill is used to burn off the solder resist ink and the polymer layer 130 that have not been developed in the hole wall of the positioning hole 101.

[0049] And because during the development process, the portion of the solder resist ink layer 120 formed in the positioning hole 101 corresponding to the set pattern 14 is exposed and cannot be removed by development, the polymer layer 130 corresponding to the second set pattern 14 is similar to an arm, so that the polymer layer 130 in the hole can be effectively bonded to the inner wall of the positioning hole 101, and completely avoids the possibility of being broken through and bonded back to the conductive layer 110 or the core board 100 close to the edge of the positioning hole 101, thereby effectively ensuring the aperture size of the positioning hole 101 and the absence of ink residue in the hole of the positioning hole 101 and on the conductive layer 110 or the core board 100, thereby effectively improving the quality and product yield of the final finished circuit board to obtain a finished circuit board.

[0050] Different from the prior art, the processing method of the circuit board in the present application forms a positioning hole on the circuit board, and then forms a solder resist ink layer on the circuit board. After the solder resist ink layer fills the positioning hole, an exposure film with a non-light-blocking area having a set pattern opposite to the positioning hole is attached to the solder resist ink layer to expose the solder resist ink layer. This can effectively prevent part of the solder resist ink in the positioning hole from sticking to the edge of the circuit board corresponding to the positioning hole when the exposed solder resist ink layer is developed. This can enable the developed circuit board to be laser burned opposite to the positioning hole to remove the solder resist ink in the positioning hole, thereby effectively improving the quality of the final circuit board and the yield rate of the product.

[0051] See also Figure 2 , Figure 2 1 is a flow chart of a second embodiment of the circuit board processing method of the present application. The circuit board processing method of this embodiment is Figure 1a A schematic flow chart of a detailed embodiment of a method for processing a circuit board in the present invention comprises the following steps:

[0052] S21: After drilling holes on the circuit board to form positioning holes on the circuit board, copper deposition, electroplating and patterning are sequentially performed on the circuit board.

[0053] Among them, S21 and Figure 1a For details, please refer to S11 and its related text descriptions, which will not be repeated here.

[0054] S22: Perform solder mask pre-treatment on the circuit board after pattern production to remove debris on two opposite sides of the circuit board.

[0055] Specifically, before performing solder mask treatment on the circuit board, it is necessary to first perform solder mask pre-treatment on the circuit board. For example, the opposite sides of the core board 100 of the circuit board and the position on the conductive layer 110 where the solder mask ink layer 120 is intended to be formed are cleaned to remove any impurities that may exist therein, thereby preventing the conductive layer 110 and the core board 100 from having insufficient bonding strength with the solder mask ink layer 120 when a solder mask ink layer 120 is subsequently coated or printed on the conductive layer 110 and the opposite sides of the core board 100.

[0056] S23: performing solder resist coating and solder resist flattening on the circuit board after the solder resist pre-treatment to form a solder resist ink layer on two opposite sides of the circuit board, and allowing the solder resist ink layer to fill the positioning hole.

[0057] Furthermore, the circuit board after the solder resist pre-treatment is coated with solder resist to form a solder resist ink layer 120. In order to ensure the flatness of the circuit board, in the process of coating the solder resist ink on the conductive layer 110, the solder resist needs to be flattened. For example, the fluidity of the solder resist ink is increased by heating and the mechanical pressure is applied to it by a high-flatness steel plate, so that the solder resist ink with uneven surface coated on the opposite sides of the circuit board can be leveled. In this process, the positioning hole 101 that was not originally filled with solder resist ink is filled with flowing solder resist ink, that is, the solder resist ink layer 120 formed finally is filled in the positioning hole 101.

[0058] S24: attaching an exposure film having a non-light-blocking area with a set pattern facing the positioning hole onto the solder resist ink layer to expose the solder resist ink layer.

[0059] S25: Developing the exposed solder resist ink layer, performing laser hole burning on the developed circuit board facing the positioning hole, so as to remove the solder resist ink in the positioning hole.

[0060] Among them, S24 and S25 are respectively Figure 1a S13 and S14 are the same. For details, please refer to S13 and S14 and their related text descriptions, which will not be repeated here.

[0061] Based on the general inventive concept, the present application also provides a circuit board, wherein the circuit board is obtained by the circuit board processing method as described in any one of the above items.

[0062] Different from the prior art, the processing method of the circuit board in the present application forms a positioning hole on the circuit board, and then forms a solder resist ink layer on the circuit board. After the solder resist ink layer fills the positioning hole, an exposure film with a non-light-blocking area having a set pattern opposite to the positioning hole is attached to the solder resist ink layer to expose the solder resist ink layer. This can effectively prevent part of the solder resist ink in the positioning hole from sticking to the edge of the circuit board corresponding to the positioning hole when the exposed solder resist ink layer is developed. This can enable the developed circuit board to be laser burned opposite to the positioning hole to remove the solder resist ink in the positioning hole, thereby effectively improving the quality of the final circuit board and the yield rate of the product.

[0063] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for processing a circuit board, characterized in that: The processing method of the circuit board comprises: After drilling holes on the circuit board to form positioning holes on the circuit board, copper deposition, electroplating and patterning are sequentially performed on the circuit board; Forming a solder resist ink layer on the circuit board after pattern production, and allowing the solder resist ink layer to fill the positioning hole; An exposure film having a non-light-blocking area with a set pattern facing the positioning hole is attached to the solder resist ink layer to expose the solder resist ink layer; wherein the set pattern is located within the projection of the positioning hole on one side of the exposure film, the set pattern comprises a first pattern portion and a plurality of second pattern portions, the first pattern portion and the positioning hole have the same pattern style, the first pattern portion and the projection of the positioning hole on one side of the exposure film have the same geometric center, and the plurality of second pattern portions all extend from the outer edge of the first pattern portion to a direction away from the geometric center of the first pattern portion with a set width; The exposed solder resist ink layer is developed, and laser hole burning is performed on the developed circuit board facing the positioning hole to remove the solder resist ink in the positioning hole.

2. The method for processing a circuit board according to claim 1, characterized in that: The set width is 0.08-0.12 mm, and the minimum distance between the second pattern portion and the inner wall of the positioning hole is 10-15 μm.

3. The method for processing a circuit board according to claim 1, characterized in that: The included angles formed by the central axes of every two adjacent second pattern portions and the geometric centers of the first pattern portions are the same.

4. The method for processing a circuit board according to claim 1, characterized in that: The positioning hole is a circular hole, the first pattern portion is a concentric circle of the projection of the positioning hole on one side of the exposure film, and the diameter of the first pattern portion is 80% of the cross-sectional diameter of the positioning hole.

5. The method for processing a circuit board according to claim 1, characterized in that: The number of the second pattern parts is 4, and the angle formed by the center of each two adjacent second pattern parts and the first pattern part is a right angle.

6. The method for processing a circuit board according to claim 1, characterized in that: The positioning hole is a straight-sided elliptical hole, the first pattern portion is a straight-sided elliptical hole, and the number of the second pattern portions is 8.

7. The method for processing a circuit board according to claim 1, characterized in that: After drilling the circuit board to form the positioning hole on the circuit board, after copper deposition, electroplating and pattern production are sequentially performed on the circuit board, before forming a solder resist ink layer on the circuit board after pattern production and filling the positioning hole with the solder resist ink layer, the method further includes: Performing solder mask pre-treatment on the circuit board after pattern production to remove debris on two opposite sides of the circuit board; The step of forming a solder resist ink layer on the circuit board after the pattern is produced and filling the positioning hole with the solder resist ink layer comprises: Solder resist coating and solder resist flattening are performed on the circuit board after solder resist pre-treatment to form the solder resist ink layer on two opposite sides of the circuit board, and the solder resist ink layer fills the positioning hole.

8. A circuit board, characterized in that: The circuit board is obtained by the circuit board processing method according to any one of claims 1 to 7.

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