A method for manufacturing a circuit board having edge-inlet sockets

Abstract

This invention discloses a method for manufacturing a circuit board with an edge-mounted internal interface. The method involves fabricating a surface core board with copper-plated through-holes and a stepped circuit pattern on one side; fabricating a prepreg with open windows and setting a release layer within the open window pattern to form an intermediate core board; stacking the intermediate core board between two surface core boards and then laminating them to form a laminated board; sequentially fabricating surface circuit patterns and dry film patterns on the laminated board; then deep milling to expose and remove the release layer to form an edge-mounted grooved board; micro-etching the edge-mounted grooved board and electroplating gold fingers; after the entire board is formed, removing the film to form the circuit board; by placing the gold fingers on the edge of the circuit board, an embedded internal interface is formed, effectively utilizing the circuit board space and solving the problem of space congestion that may occur with multiple electronic modules in a small space. The entire processing is effectively coordinated, the overall processing is simple, high-precision processing is achieved, and the service life of the circuit board is improved.

Description

Technical Field

[0001] This invention relates to the field of circuit board manufacturing, and more particularly to a method for manufacturing a circuit board with an inner insertion port on the board edge. Background Technology

[0002] With the development of consumer electronics and automotive electronics, the functions of related products are becoming more and more numerous, thus increasing the demand for high-density circuit boards.

[0003] Gold fingers are typically distributed on the surface of a circuit board to meet the needs of plugging or soldering, especially by soldering connectors to connect wire harnesses or flexible circuit boards or other circuit boards to realize some electronic functions. However, soldering connectors has certain requirements for processing conditions, and connectors occupy a certain amount of space. Therefore, for electronic modules that require multiple functions to be implemented in a small space, space congestion problems will occur.

[0004] Existing technologies achieve high-density applications of electronic modules by reducing circuit board size and the volume of connectors, but this also brings corresponding drawbacks. On the one hand, the reduction in circuit board size increases the wiring density per unit area; on the other hand, the reduction in the size of connectors, making them more precise components, increases manufacturing difficulty, leading to higher manufacturing costs and a higher scrap rate.

[0005] Therefore, in order to solve the problems mentioned in the background art, it is necessary to provide a method for manufacturing a circuit board with an inner socket on the board edge. Summary of the Invention

[0006] This invention aims to address the comprehensive performance issues of existing circuit boards, such as the requirement for high-density application of electronic modules. It proposes a method for manufacturing a circuit board with an inner interposer at the board edge. During the manufacturing process, the area within the forming line of the circuit board is the effective area, and the remaining area is the ineffective area. The effective area of ​​the circuit board includes a circuit pattern area and a gold finger area, with the gold finger area corresponding to the inner interposer at the board edge. The manufacturing method includes the following steps:

[0007] S10: Fabricate a surface core board with copper-plated through holes and a stepped circuit pattern on one side; the stepped circuit pattern is composed of a fully etched circuit pattern in the circuit pattern area and an incompletely etched circuit pattern in the gold finger area; the copper-plated through holes are located near the area of ​​the incompletely etched circuit pattern.

[0008] S20: Take a prepreg, make a window pattern, and set a release layer in the window pattern to form an intermediate core board; the release layer corresponds to the gold finger area and extends into the area covering the copper-plated through hole.

[0009] S30: The intermediate core board is placed between the two surface core boards to form a stacked structure, and then pressed together to form a press plate; the stepped circuit patterns of the two surface core boards in the stacked structure are arranged opposite to each other, and the copper-plated through holes are located in the area of ​​the release layer;

[0010] S40: The laminated plate is sequentially fabricated with surface circuit patterns, dry film patterns, and controlled-depth milling to expose a portion of the release layer. The release layer is then removed to form a plate edge groove plate. The controlled-depth milling is performed on the area where the release layer extends beyond the copper-plated through-hole. The milling depth is from the plate surface to the surface of the release layer.

[0011] S50: Micro-etch the grooved plate on the edge of the board, and the incompletely etched lines form gold finger lines. Then, the gold fingers are electroplated, the whole board is formed, and then the film is removed to form the circuit board.

[0012] Furthermore, the surface core board is fabricated as follows: a double-sided copper-clad laminate is used to create through holes and electroplated to form the copper-plated through holes. Then, a first dry film pattern is created on the first side of the double-sided copper-clad laminate, and a first etching is performed. Then, a second dry film pattern is created on the gold finger area of ​​the first side, and a second etching is performed. Finally, the film is removed to form a stepped line and the surface core board is formed.

[0013] Furthermore, after the first etching, the remaining thickness of the etched circuit pattern in the circuit pattern area is 3 micrometers to 8 micrometers; the second etching is to form the fully etched circuit pattern.

[0014] Furthermore, one side of the release layer is larger than the gold finger area.

[0015] Furthermore, the stepped circuit pattern extends into the invalid region.

[0016] Furthermore, the copper-plated through-holes are micropores.

[0017] Furthermore, the release layer is smaller on one side than the window pattern.

[0018] Furthermore, the dry film pattern exposes the electroplating clip position of the electroplated gold fingers.

[0019] Furthermore, fabricating the surface core board includes creating a conductive circuit pattern in the ineffective area, the conductive circuit pattern connecting the electroplating chuck position and the copper plating through hole.

[0020] Furthermore, the release layer is made of PI material, PTFE material, or low-flow prepreg.

[0021] The technical solution of this invention effectively utilizes the circuit board space by placing the gold fingers on the edge of the circuit board to form a groove-type internal insertion interface, thus solving the problem of space congestion that may occur when there are many electronic modules in a small space. By etching in stages and sections to form stepped lines, the etching precision of the circuit can be controlled, corresponding to the prepreg and release layer. Then, in the subsequent process, the release layer is milled to expose and remove it, forming a groove with incompletely etched lines. The subsequent etching and electroplating processes are then carried out to form the finished circuit board. The entire processing is effectively coordinated, the overall processing is simple, high-precision processing can be achieved, and the service life of the circuit board is improved. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the process flow of an embodiment of the present invention;

[0024] Figure 2 This is a plan view of the surface core plate according to an embodiment of the present invention;

[0025] Figure 3 As an embodiment of the present invention Figure 2 A schematic diagram of the AA section of the surface core board;

[0026] Figure 4 As an embodiment of the present invention Figure 2 A schematic diagram of the BB cross-section of the surface core board;

[0027] Figure 5 Use of embodiments of the present invention Figure 3 A schematic diagram of the stacked structure formed by the AA section in the middle;

[0028] Figure 6 Use of embodiments of the present invention Figure 4 Schematic diagram of the cross-sectional structure of the press-fit plate formed by the BB section;

[0029] Figure 7 As an embodiment of the present invention Figure 6 A schematic diagram of the CC-plane structure of the pressed plate;

[0030] Figure 8 For the embodiments of the present invention Figure 6 A schematic diagram of the cross-sectional structure of the grooved plate edge formed by the processing of the pressed plate;

[0031] Figure 9 For the embodiments of the present invention Figure 8 A schematic diagram of the cross-sectional structure of the gold finger plate formed by processing the grooved plate on the edge of the plate;

[0032] Figure 10 For the embodiments of the present invention Figure 9 A schematic diagram of the cross-sectional structure of a circuit board with an inner insertion port on the board edge, formed by processing a gold finger board.

[0033] Explanation of icon numbers:

[0034]

[0035] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that all directional indications (such as up, down, left, right, front, back, inside, outside, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0038] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0039] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0040] Please see Figure 1 , Figure 1 This is a schematic diagram of the process flow according to an embodiment of the present invention.

[0041] The manufacturing process of this invention includes using Figure 1 The implementation of each step in the process will be described below. Figure 1 The process of each step will be explained step by step.

[0042] In this embodiment, the area within the forming line 10 of the circuit board during the processing is the effective area 101, and the remaining area is the ineffective area 102. The effective area 101 of the circuit board includes the circuit pattern area 1010 and the gold finger area 1020, and the gold finger area 1020 corresponds to the inner insertion port on the edge of the board.

[0043] Please see Figure 2 , Figure 3 and Figure 4 , Figure 2 This is a plan view of the surface core plate according to an embodiment of the present invention; Figure 3 As an embodiment of the present invention Figure 2 A schematic diagram of the AA section of the surface core board; Figure 4 As an embodiment of the present invention Figure 2 A schematic diagram of the BB cross-section of the surface core board.

[0044] Step S10:

[0045] A surface core board 20 is fabricated with copper-plated through holes 2010 and a stepped circuit pattern 2020 on one side; the stepped circuit pattern 2020 consists of a fully etched circuit pattern 2020A in the circuit pattern area 1010 and an incompletely etched circuit pattern 2020B in the gold finger area 1020.

[0046] In this embodiment, the surface core board 20 is fabricated as follows: A double-sided copper-clad laminate is used to create through-holes and electroplated to form copper-plated through-holes 2010, providing a conductive channel for the subsequent electroplating of gold fingers. Then, a first dry film pattern is fabricated on the first side of the double-sided copper-clad laminate, followed by a first etching. The first dry film pattern is created on the circuit pattern area 1010 and the gold finger area 1020. Through the first etching, the circuit patterns in both the circuit pattern area 1010 and the gold finger area 1020 are incompletely etched circuit patterns 1020A, providing a processing basis for the second etching to form the stepped circuit pattern 2020. Then, the gold finger area on the first side... 1020. The second dry film pattern is created, that is, the incomplete etched circuit pattern 2020B of the gold finger area 1020 is covered with the second dry film pattern to form protection, and then a second etching is performed, and then the film is removed. At this time, the circuit pattern in the circuit pattern area 1010 is completely etched circuit pattern 2020A, while the incomplete etched circuit pattern 2020B of the gold finger area 1020 is not etched. They are combined to form the stepped circuit pattern 2020, forming the surface core board 20. The other complete copper surface of the double-sided copper-clad board provides a processing base for subsequent lamination processes, ensuring that the board surface of the circuit board is uniformly stressed during lamination, and increasing the reliability of the circuit board.

[0047] In the aforementioned process of fabricating the stepped circuit pattern 2020, during the subsequent lamination process, the fully etched circuit pattern 2020A is laminated with the prepreg to form an adhesive bond, while the partially etched circuit pattern 2020B is laminated with the release layer 3020 to form a non-adhesive bond, creating a non-adhesive area. If this non-adhesive area were directly and fully etched to become the fully etched circuit pattern 2020A, problems such as circuit bending or misalignment could easily occur during lamination. Therefore, the stepped circuit pattern 2020 effectively avoids problems such as circuit bending, misalignment, or short circuits during lamination. The step-by-step, zoned etching process used in fabricating the stepped circuit pattern 2020 allows each step to be optimized independently, enabling better control of the etching process, reducing rework caused by improper etching, and improving processing quality.

[0048] In this embodiment, the copper-plated through-hole 2010 is located near the area of ​​the incompletely etched circuit pattern 2020B, that is, the copper-plated through-hole 2010 is adjacent to the gold finger area 1020. Since the release layer 3020 in the subsequent process extends to cover the location of the copper-plated through-hole 2010 on one side, the position of the copper-plated through-hole 2010 affects the size of the release layer 3020. Therefore, the copper-plated through-hole 2010 is adjacent to the gold finger area 1020, so that the area of ​​the release layer 3020 is the minimum area under the premise of ensuring the realization of the present invention. Furthermore, since the smaller the area of ​​the release layer 3020, the more the incompletely etched circuit pattern 2020B and the release layer 3020 overlap to form a non-bonded area, it is less likely to cause problems such as circuit bending or misalignment during the pressing process.

[0049] Furthermore, after the first etching, the remaining thickness of the etched circuit pattern in the circuit pattern area 1010 is 3 to 8 micrometers; that is, the copper layer remaining after the first etching is the connecting copper layer 2020C, which has a thickness of 3 to 8 micrometers, providing a processing basis for the subsequent formation of the stepped circuit pattern 2020; the second etching is a selective etching, which protects the circuit pattern in the gold finger area 1020 with a dry film, and then completely etches away the connecting copper layer 2020C in the circuit pattern area 1010 to form a fully etched circuit pattern 2020A.

[0050] In this embodiment, the copper-plated through-hole 2010 is a micro-hole. Because the diameter of the micro-hole is small, it can form a solid effect under pressure during the subsequent pressing process, which can better prevent pressing deformation and prevent problems such as delamination and board bursting caused by the hole position in further processing. Furthermore, processing technologies such as laser drilling or mechanical drilling can be used. The micro-hole size formed by laser drilling is 20 micrometers to 30 micrometers, and the micro-hole size formed by mechanical drilling is 0.15mm to 0.25mm.

[0051] Please see Figure 5 , Figure 5Use of embodiments of the present invention Figure 3 A schematic diagram of the stacked cross-section structure formed by the AA section.

[0052] Step S20:

[0053] Take a prepreg and make a window pattern 3010. Set a release layer 3020 in the window pattern 3010 to form an intermediate core board 30. The release layer 3020 corresponds to the gold finger area 1020 and extends into the area covering the copper-plated through hole 2010.

[0054] It is worth noting that since the release layer 3020 needs to be removed in the subsequent process and cannot form an adhesive with the surface core board 20, it is easy to move within the window pattern 3010 during the pressing process. Therefore, one side of the release layer 3020 extends to cover the copper-plated through hole 2010, but does not exceed the edge of the board. This can effectively prevent the release layer 3020 from falling off or becoming misaligned after pressing and squeezing. Furthermore, it also provides a good processing foundation for subsequent processing.

[0055] In this embodiment, due to the expansion and contraction of the board material during the pressing process, the "copper layer" in the ineffective area 102 may enter the gold finger area 1020. When the subsequent process is formed and punched according to the original design, this excess "copper layer" that has entered the gold finger area 1020 is not removed, thus forming an incomplete etched circuit pattern 2020B connected with the gold finger area 1020, resulting in a short circuit. Therefore, the other sides of the release layer 3020 are larger than the gold finger area 1020 on one side, preferably 20 micrometers to 50 micrometers.

[0056] In this embodiment, the release layer 3020 is made of PI material, PTFE material, or low-flow prepreg. Compared with the common epoxy resin-glass fiber material commonly used in circuit boards, the release layer 3020 has stronger inertness and can form a non-adhesive effect with the circuit board material, thereby forming a release effect.

[0057] Please refer to it again. Figure 5 And see Figure 6 and Figure 7 , Figure 6 Use of embodiments of the present invention Figure 4 Schematic diagram of the cross-sectional structure of the press-fit plate formed by the BB section; Figure 7 As an embodiment of the present invention Figure 6 A schematic diagram of the CC plane structure of the pressed plate.

[0058] Step S30:

[0059] An intermediate core board 30 is placed between two surface core boards 20 to form a stacked structure 40, which is then pressed together to form a press plate 50. The stepped circuit patterns 2020 of the two surface core boards 20 in the stacked structure 40 are arranged opposite to each other, and the copper-plated through holes 2010 are located in the area of ​​the release layer 3020.

[0060] Because the release layer 3020 has a window pattern 3010, which restricts the movement of the release layer 3020, and the board material expands and contracts during the pressing process, the copper foil of the window pattern 3010 is squeezed into the release layer 3020, causing compression of the release layer 3020 and resulting in problems such as local protrusions in the pressed plate 50. Therefore, in this embodiment, the release layer 3020 is smaller than the window pattern 3010 on one side, preferably less than 20 to 50 micrometers, to provide expansion and contraction space for the board material during the pressing process, effectively avoiding problems such as poor pressing, and also providing a good board surface foundation for subsequent processing.

[0061] During the lamination process, the colloid of the prepreg is prone to flow, which may cause the copper layer in the invalid region 102 to enter the range of the molding line 10. After molding, the copper layer cannot be completely removed, resulting in problems such as short circuits. Therefore, in this embodiment, the stepped circuit pattern 2020 extends to the invalid region 102, effectively preventing the copper layer in the invalid region 102 from entering the molding line during lamination.

[0062] Please see Figure 8 , Figure 8 For the embodiments of the present invention Figure 6 A schematic diagram of the cross-sectional structure of the grooved plate formed by the processing of the pressed plate.

[0063] Step S40:

[0064] The surface circuit pattern, dry film pattern 6010, and controlled-depth milling are sequentially made on the press plate 50 to expose the partial release layer 3020. Then the release layer 3020 is removed to form the plate edge groove plate 60.

[0065] Unlike common processing methods that place the fabrication of surface circuit patterns in the pre-forming and punching process, in this embodiment, the surface circuit patterns are fabricated on the laminating plate 50. On the one hand, after the release layer 3020 is removed in the subsequent process, the laminating plate 50 forms an initial depression 6020. If the surface circuit patterns are fabricated at this time, the pressing force during the lamination of the dry film will cause the board surface to be depressed, resulting in poor film adhesion and problems such as short circuits. On the other hand, the electroplating process in the subsequent process involves a high-temperature process. Under the temperature conditions, the dry film and the copper layer of the surface core board 20 will form a strong bonding layer, which is not conducive to the subsequent fabrication of surface circuit patterns.

[0066] Furthermore, a dry film pattern 6010 is made after the surface circuit pattern, which plays a protective and isolating role on the circuit pattern on the surface of the laminating board 50, avoiding the impact of subsequent micro-etching and electroplating on the surface circuit pattern, and effectively avoiding the occurrence of problems such as short circuits.

[0067] In this embodiment, controlled-depth milling is performed along the controlled-depth milling line 5010 in the area of ​​the release layer 3020 that exceeds the copper-plated through hole 2010. The milling depth is from the board surface to the surface of the release layer 3020. In particular, the controlled-depth milling line 5010 is located in the area between the copper-plated through hole 2010 and the edge of the release layer 3020. After milling away the controlled-depth area and the board edge area, a structure is formed in which the release layer 3020 protrudes from the board edge for easy removal. Then, the release layer 3020 is removed to form the initial state recess 6020.

[0068] In this embodiment, the dry film pattern 6010 is the electroplating clip position 6030 that exposes the electroplated gold fingers, providing conductive conditions for forming a conductive channel.

[0069] Please see Figure 9 and Figure 10 , Figure 9 For the embodiments of the present invention Figure 8 A schematic diagram of the cross-sectional structure of the gold finger plate formed by processing the grooved plate on the edge of the plate; Figure 10 For the embodiments of the present invention Figure 9 A schematic diagram of the cross-sectional structure of a circuit board with an inner insertion port on the board edge, formed by processing a gold finger board.

[0070] Step S50:

[0071] Micro-etching is performed on the edge groove plate 60 to etch the remaining incomplete etched circuit pattern 2020B (i.e. the remaining 3-micron to 8-micron connecting copper layer 2020C) from the previous step, so that the incomplete etched circuit pattern 2020B forms gold finger circuits. Then, gold is electroplated to form gold fingers 7010, and the board body forms gold finger plate 60A. The whole board is formed, and then the film is removed to form a circuit board 70 with an inner socket on the edge of the board.

[0072] In this embodiment, during the fabrication of the surface core board 20, a conductive circuit pattern is also fabricated in the ineffective area 102. The conductive circuit pattern connects the electroplating chuck position 6030 and the copper plating through hole 1020 to form a circuit of conductive channel, providing conductive conditions for the electroplating of the gold finger 7010.

[0073] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for manufacturing a circuit board with an inner insertion port on the board edge, characterized in that, The area within the forming line range of the circuit board during processing is the effective area, and the remaining area is the ineffective area. The effective area of ​​the circuit board includes the circuit pattern area and the gold finger area. The gold finger area corresponds to the inner insertion port on the edge of the board. The manufacturing method includes the following steps: S10: Fabrication of a surface core board with copper-plated through holes and a stepped circuit pattern on one side; The stepped circuit pattern is composed of a fully etched circuit pattern in the circuit pattern area and an incompletely etched circuit pattern in the gold finger area. The copper-plated through-hole is located near the area of ​​the incompletely etched circuit pattern. S20: Take a semi-cured sheet, make a windowed pattern, and set a release layer in the windowed pattern to form an intermediate core board; The release layer corresponds to the gold finger area and extends into the area covering the copper-plated through-hole. S30: The intermediate core board is placed between the two surface core boards to form a stacked structure, and then pressed together to form a press-fit plate; The stepped circuit patterns of the two surface core boards in the stacked structure are arranged opposite each other, and the copper-plated through holes are located in the area of ​​the release layer. S40: The surface circuit pattern, dry film pattern and controlled depth milling are sequentially made on the press plate to expose part of the release layer, and then the release layer is removed to form a plate edge groove plate; The controlled-depth milling involves milling the area of ​​the release layer that extends beyond the copper-plated through-hole, with the milling depth extending from the board surface to the surface of the release layer. S50: Micro-etch the grooved plate on the edge of the board, and the incompletely etched lines form gold finger lines. Then, the gold fingers are electroplated, the whole board is formed, and then the film is removed to form the circuit board.

2. The method for manufacturing a circuit board with an inner insertion port on the board edge as described in claim 1, characterized in that, The surface core board is fabricated as follows: a double-sided copper-clad laminate is used to make through holes and electroplated to form the copper-plated through holes. Then, a first dry film pattern is made on the first side of the double-sided copper-clad laminate, and a first etching is performed. Then, a second dry film pattern is made on the gold finger area of ​​the first side, and a second etching is performed. Then, the film is removed to form a stepped line and the surface core board is formed.

3. The method for manufacturing a circuit board with an inner insertion port on the board edge as described in claim 2, characterized in that, After the first etching, the remaining thickness of the etched circuit pattern in the circuit pattern area is 3 to 8 micrometers; the second etching is to form the fully etched circuit pattern.

4. The method for manufacturing a circuit board with an inner insertion port on the board edge as described in claim 1, characterized in that, The release layer is larger on one side than the gold finger area.

5. A method for manufacturing a circuit board with an inner insertion port on the board edge as described in claim 1, characterized in that, The stepped circuit pattern extends into the invalid area.

6. A method for manufacturing a circuit board with an inner insertion port on the board edge as described in claim 1, characterized in that, The copper-plated through-holes are micropores.

7. A method for manufacturing a circuit board with an inner insertion port on the board edge as described in claim 1, characterized in that, The release layer is smaller on one side than the window pattern.

8. A method for manufacturing a circuit board with an inner insertion port on the board edge as described in claim 2, characterized in that, The dry film pattern is the electroplating clip position that exposes the electroplated gold fingers.

9. A method for manufacturing a circuit board with an inner insertion port on the board edge as described in claim 8, characterized in that, Fabricating the surface core board includes creating a conductive circuit pattern in the invalid area, the conductive circuit pattern connecting the electroplating chuck position and the copper plating through hole.

10. A method for manufacturing a circuit board with an inner insertion port on the board edge as described in claim 1, characterized in that, The release layer is made of PI material, PTFE material, or low-flow prepreg.

Images