Method for manufacturing circuit board edge metalized half hole

Abstract

The invention discloses a method for manufacturing a circuit board edge metalized half hole, which comprises the following steps of: drilling a through hole at a design position corresponding to the half hole in a board edge ineffective area, forming a through groove for each through hole along a forming line in the board edge ineffective area, metallization layers are electroplated on the through holes and the through grooves; manufacturing a wet film layer covering the metalized layer to form a wet film plate; removing the wet film layer on the forming line corresponding to the wet film plate, etching the metalized layer on the corresponding forming line, and stripping the effective half hole to form a metalized half hole; the through groove is milled from inside to outside of the hole, so that the drilling process is optimized, and burrs and burrs generated in the drilling process are reduced; by means of the mode that the wet film layer is milled firstly and then the metallization layer is etched, the error tolerance of milling machining is higher, the problems that the metallization layer in the half hole is prone to being snapped, deformed and the like due to direct milling are solved, the overall machining process is simple, and high-precision machining is achieved.

Description

Technical Field

[0001] The invention relates to the field of circuit board manufacturing, and in particular to a method for manufacturing a metallized half hole at an edge of a circuit board. Background Art

[0002] In order to meet the specific line conduction requirements of a type of power module, the circuit board is usually designed with a metallized half hole on the edge of the board, and the connection area between the half holes is required to be a non-metallized layer.

[0003] At present, the method for making the metallized half-holes on the edge of this type of circuit board is: first shape the edge of the circuit board, then drill a half-hole by drilling, further electroplating to form a metallized layer, and finally mill off the metallized layer in the connection area between adjacent half-holes to form a half-hole metallized layer.

[0004] The above production method has defects: (1) When drilling a half hole, the drill cutter milling the edge of the plate can easily cause burrs and flashes at the top corners of the half hole, which in turn affects the electroplating process in the subsequent process and easily causes copper nodules and uneven electroplating.

[0005] (2) When milling off the metallization layer in the connection area between adjacent half holes, high-precision milling processing is required. On the one hand, due to the expansion and contraction of each plate body, the edge size of the plate body is inconsistent, and high-precision milling is prone to insufficient or excessive milling. On the other hand, milling the metallization layer is prone to pulling, causing the metallization layer in the half hole to break or deform. In addition, after milling, the metallization layer at the top corner of the half hole is prone to plating burrs and flashes, leading to problems such as poor application.

[0006] Therefore, in order to solve the problems raised by the above background technology, it is necessary to provide a method for manufacturing a metallized half hole at the edge of a circuit board. Summary of the invention

[0007] The present invention aims to solve the problem that the metallized half hole at the edge of the circuit board in the prior art requires high-precision processing, and proposes a method for manufacturing the metallized half hole at the edge of the circuit board, the manufacturing method comprising the following steps: S10: the circuit board includes an invalid area distributed around the board edge during the processing, and a through hole is drilled at a designed position corresponding to the half hole to form a through-hole board; The portion of the through hole located in the invalid area of ​​the plate edge is an invalid half hole, and the remaining portion is an effective half hole; S20: forming a through groove along the molding line in the ineffective area of ​​the board edge for each through hole, electroplating the through hole and the through groove to form a metallization layer, and then forming a wet film layer covering the metallization layer to form a wet film board; S30: removing the wet film layer on the wet film plate corresponding to the forming line, and then etching the metallization layer on the corresponding forming line to form a semi-porous metal plate; S40: stripping the half-hole metal plate, so that the effective half-hole forms the metallized half-hole.

[0008] Furthermore, after the wet film plate is formed, the invalid area at the edge of the plate where the invalid half hole in the wet film plate is located is removed.

[0009] Furthermore, the process of removing the invalid area at the edge of the plate where the invalid half hole in the wet film plate is located is to perform milling from the through groove to outside the invalid area at the edge of the plate.

[0010] Furthermore, the through groove is made by milling the invalid area of ​​the plate edge along the molding line from the invalid half hole from inside to outside in two opposite directions to form the through groove.

[0011] Furthermore, the through grooves of adjacent through holes intersect with each other.

[0012] Furthermore, the wet film layer is manufactured by coating a wet film on the area where the through hole and the through groove are located, and then baking and curing the wet film layer.

[0013] Furthermore, the wet film coating is performed multiple times, and baking and curing are performed after each coating of the multiple coatings.

[0014] Furthermore, the wet film layer is made by: immersing the area where the through hole and the through groove are located in a wet film, then taking it out and letting it stand, and then baking and curing it to form the wet film layer.

[0015] Furthermore, the removing of the wet film layer on the wet film plate corresponding to the forming line is performed by milling.

[0016] Furthermore, the metallization layer is manufactured by applying a dry film to the areas outside the hole rings of the through holes and the through slots, and then performing electroplating and film stripping in sequence to form the metallization layer.

[0017] The technical solution of the present invention optimizes the drilling process by drilling a through hole at the position corresponding to the half hole and then milling a through groove from the inside of the hole to the outside, thereby reducing burrs and flash generated during the drilling process, and solving the problem that the milling of the edge of the board in the prior art easily leads to burrs and flash at the top corner of the half hole. The through groove is first electroplated and then a wet film layer is made, and when removing the metallization layer of the connecting area between adjacent half holes, the wet film layer is first milled and then the metallization layer is etched. On the one hand, the error tolerance of the milling process is increased, and the problem of insufficient or excessive milling caused by the high-precision milling of the metallization layer in the prior art is avoided. On the other hand, chemical etching is used instead of physical milling, which solves the problems that the direct milling in the prior art easily leads to the breaking and deformation of the metallization layer in the half hole due to pulling, and the metallization layer at the top corner of the half hole after milling easily generates burrs and flash of the plating, resulting in poor application. The front and rear processes cooperate with each other, the overall processing process is simple, high-precision processing is achieved, and the service life of the circuit board is increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0019] Figure 1 Schematic diagram of the process flow of an embodiment of the present invention; Figure 2 A schematic plan view of a through-hole plate according to an embodiment of the present invention; Figure 3 A schematic plan view of a through-groove plate according to an embodiment of the present invention; Figure 4 A schematic plan view of a single through slot according to an embodiment of the present invention; Figure 5 Schematic diagram of a wet film plate according to an embodiment of the present invention; Figure 6 It is a schematic plan view of forming an effective half-hole plate according to an embodiment of the present invention; Figure 7 A schematic plan view of a half-perforated metal plate according to an embodiment of the present invention; Figure 8 Schematic diagram of a metallized half hole according to an embodiment of the present invention.

[0020] Description of Figure Numbers:

[0021] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, inside, outside...) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0024] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0025] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0026] See also Figure 1 , Figure 1 It is a schematic diagram of the process flow of an embodiment of the present invention.

[0027] The manufacturing process of the embodiment of the present invention includes using Figure 1 The following will implement the various steps in the process Figure 1 Each step in the process is further explained step by step.

[0028] See also Figure 2 , Figure 2 Schematic diagram of a plan view of a through-hole plate according to an embodiment of the present invention.

[0029] Step S10: During the processing of the circuit board, an invalid area 1020 distributed around the edge of the board is included. A through hole 1010 is drilled at the designed position of the corresponding half hole to form a through-hole board 10; the part of the through hole 1010 located in the invalid area 1020 of the edge of the board is an invalid half hole 1010A, and the remaining part is a valid half hole 1010B.

[0030] This embodiment makes the half hole by drilling a complete through hole 1010 along the forming line 1030 and at a position corresponding to the designed half hole, and then removing a portion of the invalid half hole 1010A. On the one hand, it provides a processing basis for the subsequent process of making the through groove 2010 for the invalid half hole 1010A. On the other hand, by reducing the direct processing of the effective half hole 1010B, it effectively avoids direct milling of the effective half hole 1010B, which may easily cause burrs and burrs at the top corner position of the effective half hole 1010B, which is conducive to achieving high-precision processing.

[0031] See also Figure 3 , Figure 3 It is a schematic plan view of a through-groove plate according to an embodiment of the present invention.

[0032] Step S20: A through slot 2010 is made for each through hole 1010 in the invalid area 1020 of the board edge along the molding line 1030 to form a through slot plate 20, that is, the invalid area 1020 of the board edge is milled from the invalid half hole 1010A from the inside to the outside in two opposite directions along the molding line 1030 to form a through slot 2010. When milling from the inside of the hole to the outside, on the one hand, the milling cutter can be closely attached to the hole wall for initial positioning, so that the board body can tightly wrap the milling cutter, effectively avoiding the burrs and burrs caused by directly drilling half holes. On the other hand, the milling of the smooth groove wall also provides a closed space for the subsequent production of the wet film layer 3020, which is beneficial to better combining the wet film layer 3020 with the metallization layer 3010.

[0033] See also Figure 4 , Figure 4 It is a schematic plan view of a single through slot according to an embodiment of the present invention.

[0034] In one embodiment, the through grooves 2010 of adjacent through holes 1010 intersect to form a single through groove 2010A. On the one hand, the single through groove 2010A can reduce dead corners and bubbles that appear during the electroplating process in the subsequent process, ensure the integrity and uniformity of the metallization layer 3010, and reduce electroplating defects. Furthermore, it also provides a smooth metallization layer 3010 foundation for the production of the wet film layer 3020 in the subsequent process. On the other hand, it forms a structure that can cut off the connection between the through groove and the board surface by subsequent milling from the single through groove 2010A to the edge of the board, providing a convenient processing basis for removing the invalid area 1020 of the board edge where the invalid half hole 1010A is located in the subsequent processing.

[0035] See also Figure 5 , Figure 5 Schematic diagram of a wet film plate according to an embodiment of the present invention.

[0036] The through hole 1010 and the through slot 2010 are electroplated to form a metallization layer 3010, and then a wet film layer 3020 covering the metallization layer is made, that is, a wet film is coated or screen-printed on the area where the through hole 1010 and the through slot 2010 are located, and then baked and cured to form the wet film layer 3020, thereby forming a wet film board 30. It is worth noting that the wet film layer 3020 protects the metallization layer 3010 by isolating the etching solution. Therefore, when making the wet film layer 3020, it is directly baked and cured after the wet film is coated, without the need for conventional processes such as development and exposure.

[0037] In order to ensure the protective effect of the wet film layer 3020 on the metallization layer 3010, the wet film layer 3020 is made as follows: the area where the through hole 1010 and the through groove 2010 are located is immersed in the wet film, then taken out and left to stand, and then baked and cured to form the wet film layer 3020; on the one hand, it is ensured that the area where the through hole 1010 and the through groove 2010 are located is completely covered by the wet film layer 3020, so that the adhesion between the wet film layer 3020 and the metallization layer 3010 is stronger, and the integrity and continuity of the wet film layer 3020 are improved; on the other hand, the wet film of this embodiment is not used for graphic transfer processing, but for the subsequent milling method to remove the wet film layer 3020 on the corresponding molding line of the wet film plate 30 to provide a larger error tolerance, so it is simpler to choose the immersion method, which is easy to operate and has the beneficial effects of reducing processing steps, reducing production complexity and cost.

[0038] In one embodiment, the wet film is coated by multiple coatings or screen printings, and baking and curing are performed after each coating or screen printing, that is, a single coating and drying are performed, and the process is repeated many times. On the one hand, multiple coatings and baking and curing can expel bubbles layer by layer, avoiding defects such as sagging and foaming that are easily caused by one-time coating, making the overall wet film layer 3020 more uniform, thereby improving the quality and reliability of the wet film layer 3020. On the other hand, it has the effect of accelerating the drying and curing of the wet film layer 3020, enhancing the corrosion resistance of the wet film layer 3020, and forming a good protective effect on the metallized layer 3010.

[0039] In this embodiment, a dry film is applied to the area outside the hole ring of the through hole 1010 and the through groove 2010, and then coating or silk screen processing is performed. This method can make the wet film coating or silk screen printing more concentrated and accurate, and prevent the problem of wet film loss at the edge of the through hole 1010 and the through groove 2010. This method preferably uses silk screen wet film processing.

[0040] See also Figure 6 , Figure 6 This is a schematic plan view of forming an effective half-hole plate according to an embodiment of the present invention. Furthermore, after the wet film board 30 is formed, the invalid area 1020 at the edge of the board where the invalid half hole 1010A in the wet film board 30 is located is removed to form an effective half-hole board 40, that is, milling is performed from the through groove 2010 to outside the invalid area 1020 at the edge of the board. On the one hand, by milling away the invalid area 1020 at the edge of the board where the invalid half hole 1010A is located, the remaining part of the through hole 1010 forms an effective half hole 1010B, which provides a processing basis for the subsequent formation of the metallized half hole 6010. On the other hand, compared with the prior art method of first forming the plate body and then drilling the half hole, the effective half hole 1010B formed by the processing of this embodiment has higher precision.

[0041] See also Figure 7 , Figure 7 It is a schematic plan view of a half-perforated metal plate according to an embodiment of the present invention.

[0042] Step S30: The wet film layer 3020 on the wet film plate 30 corresponding to the forming line 1030 is removed, and then the metallization layer 3010 on the corresponding forming line 1030 is etched to form a half-hole metal plate 50 .

[0043] In this embodiment, since the metallization layer 3010 on the corresponding molding line 1030 needs to be etched away in subsequent processing, there is a larger tolerance when removing the wet film layer 3020 covering its surface, so a more convenient processing method can be selected. Different from the conventional process of using a film stripping liquid to remove the wet film layer 3020, the wet film layer 3020 on the molding line 1030 corresponding to the wet film plate 50 is removed by milling. The position and range of removing the wet film layer 3020 can be selectively controlled to ensure that the wet film layer 3020 on the molding line is completely removed without affecting the wet film layer 3020 in other areas, thereby forming an effect of selectively removing the wet film layer 3020, so that the exposed metallization layer 3010 provides a processing basis for subsequent etching.

[0044] This embodiment removes the metallization layer 3010 on the corresponding forming line 1030 by chemical etching. Compared with the prior art that directly mills off the metallization layer 3010 in the connection area between adjacent effective half holes 1010B by milling, the tolerance of processing errors is higher, so the metallized half hole 6010 formed by processing has higher precision.

[0045] See also Figure 8 , Figure 8 Schematic diagram of a metallized half hole according to an embodiment of the present invention.

[0046] Step S40: The half-hole metal plate 50 is stripped, and the effective half hole 1010B is formed into a metallized half hole 6010, and then processed in the post-process and molding process to form a circuit board 60.

[0047] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a metallized half hole on a circuit board edge, characterized in that: The production method comprises the following steps: S10: the circuit board includes an invalid area distributed around the board edge during the processing, and a through hole is drilled at a designed position corresponding to the half hole to form a through-hole board; The portion of the through hole located in the invalid area of ​​the plate edge is an invalid half hole, and the remaining portion is an effective half hole; S20: forming a through groove along the molding line in the ineffective area of ​​the board edge for each through hole, electroplating the through hole and the through groove to form a metallization layer, and then forming a wet film layer covering the metallization layer to form a wet film board; S30: removing the wet film layer on the wet film plate corresponding to the forming line, and then etching the metallization layer on the corresponding forming line to form a semi-porous metal plate; S40: stripping the half-hole metal plate, so that the effective half-hole forms the metallized half-hole.

2. A method for manufacturing a metallized half hole on a circuit board edge as claimed in claim 1, characterized in that: After the wet film plate is formed, the invalid area at the edge of the plate where the invalid half hole in the wet film plate is located is removed.

3. A method for manufacturing a metallized half hole on a circuit board edge as claimed in claim 2, characterized in that: The method of removing the invalid area at the edge of the plate where the invalid half hole in the wet film plate is located is to perform milling from the through groove to outside the invalid area at the edge of the plate.

4. A method for manufacturing a metallized half hole at the edge of a circuit board as claimed in claim 1, characterized in that: The through groove is made by milling the invalid area of ​​the plate edge along the molding line from the invalid half hole from inside to outside in two opposite directions to form the through groove.

5. A method for manufacturing a metallized half hole at the edge of a circuit board as claimed in claim 1 or 4, characterized in that: The through grooves of adjacent through holes intersect with each other.

6. A method for manufacturing a metallized half hole at the edge of a circuit board as claimed in claim 1, characterized in that: The wet film layer is made by coating or silk-screening a wet film on the area where the through hole and the through groove are located, and then baking and curing to form the wet film layer.

7. A method for manufacturing a metallized half hole at the edge of a circuit board as claimed in claim 6, characterized in that: The wet film coating is performed by multiple coatings or screen printings, and baking and curing are performed after each coating or screen printing.

8. A method for manufacturing a metallized half hole at the edge of a circuit board as claimed in claim 6, characterized in that: A dry film is applied to the area outside the hole ring of the through hole and the through groove, and then the coating or silk-screen printing process is performed.

9. A method for manufacturing a metallized half hole at the edge of a circuit board as claimed in claim 1, characterized in that: The wet film layer is made by immersing the through hole and the through groove in the wet film, then taking it out and letting it stand, and then baking and curing it to form the wet film layer.

10. The method for manufacturing a metallized half hole at the edge of a circuit board according to claim 1, characterized in that: The step of removing the wet film layer on the wet film plate corresponding to the molding line is to remove the wet film layer by milling.

Images