Manufacturing method of circuit board edge metallization half-hole

Abstract

The application discloses a manufacturing method of a circuit board edge metallization half-hole, a through hole is drilled at a design position of a half-hole corresponding to an invalid area of a board edge, a part of the through hole located in the invalid area of the board edge is an invalid half-hole, and a remaining part is an effective half-hole; a through slot is manufactured along a forming line in the invalid area of the board edge for each through hole; and a metal layer is electroplated on the through hole and the through slot; a wet film layer covering the metal layer is manufactured to form a wet film board; the wet film layer on the forming line of the wet film board is removed, the metal layer on the forming line is etched, the effective half-hole is removed from the film, and the metallization half-hole is formed; the through slot is milled from the hole to the outside to optimize the drilling process and reduce burrs and burrs generated in the drilling process; the method of milling the wet film layer first and then etching the metal layer makes the error tolerance of the milling process higher, solves the problems that the metal layer in the half-hole is easily pulled off and deformed by direct milling, and the overall processing process is simple, and high-precision processing is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of circuit board manufacturing, in particular to a manufacturing method of circuit board edge metallization half-hole. BACKGROUND

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

[0003] The current manufacturing method of the circuit board edge metallization half-hole is as follows: first, the circuit board edge is formed, then the half-hole is drilled by drilling, further electroplated to form a metalized layer, and finally the metalized layer of the connection area between adjacent half-holes is milled off to form a half-hole metalized layer.

[0004] The above manufacturing method has the following defects:

[0005] (1) When drilling the half-hole, the drill bit milling the edge of the circuit board can cause burrs and burrs at the top corner of the half-hole, which can affect the electroplating process of the subsequent process and cause copper tumors and uneven electroplating.

[0006] (2) When milling off the metalized layer of the connection area between adjacent half-holes, high-precision milling is required. On the one hand, due to the influence of the expansion and contraction of each plate body, the edge dimensions of the plate body are inconsistent, and high-precision milling can easily cause under-milling or over-milling problems; on the other hand, milling the metalized layer can cause pulling, causing the metalized layer in the half-hole to be pulled off or deformed, and the metalized layer at the top corner of the half-hole after milling can cause burrs and burrs in the plated layer, resulting in application problems.

[0007] Therefore, in order to solve the problems raised in the above background art, a manufacturing method of circuit board edge metallization half-hole is needed. SUMMARY

[0008] The present application aims to solve the problem of high-precision processing of the circuit board edge metallization half-hole in the prior art, and proposes a manufacturing method of circuit board edge metallization half-hole, which comprises the following steps:

[0009] S10: The circuit board contains a peripheral edge invalid area during processing, and a through hole is drilled at the design position corresponding to the half-hole to form a through hole plate;

[0010] The part of the through hole located in the edge invalid area is an invalid half-hole, and the remaining part is an effective half-hole;

[0011] S20: making a through slot along the forming line on the plate edge invalid area of each of the through holes, electroplating the through holes and the through slot to form a metallization layer, and then making a wet film layer covering the metallization layer to form a wet film plate;

[0012] S30: removing the wet film layer corresponding to the forming line on the wet film plate, and etching the metallization layer corresponding to the forming line to form a half-hole metal plate;

[0013] S40: removing the film from the half-hole metal plate, and forming the effective half-hole as the metallization half-hole.

[0014] Further, after the wet film plate is formed, the plate edge invalid area where the invalid half-hole is located in the wet film plate is removed.

[0015] Further, the plate edge invalid area where the invalid half-hole is located in the wet film plate is removed by milling from the through slot to outside the plate edge invalid area.

[0016] Further, the through slot is made by milling from the invalid half-hole to the two opposite directions of the plate edge invalid area along the forming line to form the through slot.

[0017] Further, the through slots of adjacent through holes intersect with each other.

[0018] Further, the wet film layer is made by coating wet film on the area where the through holes and the through slots are located, and then baking and curing to form the wet film layer.

[0019] Further, the wet film is coated multiple times, and baking and curing are performed after each coating.

[0020] Further, the wet film layer is made by immersing the area where the through holes and the through slots are located in wet film, then taking out and standing, and then baking and curing to form the wet film layer.

[0021] Further, the wet film layer corresponding to the forming line on the wet film plate is removed by milling.

[0022] Further, the metallization layer is made by pasting dry film on the area outside the hole ring of the through holes and the through slots, and then sequentially performing electroplating and film removal to form the metallization layer.

[0023] The technical scheme of the present application realizes optimization of the drilling process by drilling a through hole at the position corresponding to the half hole and then milling a through groove from the hole to the outside, reduces burrs and burrs generated in the drilling process, and solves the problem that the existing technology milling plate edge easily causes burrs and burrs to appear at the top corner position of the half hole; by electroplating the through groove first and then making a wet film layer, and by using the method of milling the wet film layer first and then etching the metallized layer when removing the metallized layer of the connecting area between adjacent half holes, on the one hand, the error tolerance of the milling process is increased, avoiding the problem that the existing technology requires high-precision milling of the metallized layer, which is prone to under-milling or over-milling; on the other hand, the chemical etching method is used instead of the physical milling method, solving the problems that the existing technology directly milled is prone to pulling, causing the metallized layer in the half hole to be pulled off and deformed, and the metallized layer at the top corner of the half hole after milling is prone to burrs and burrs of the plated layer, causing poor application and other problems, the front and rear processes cooperate with each other, the overall processing process is simple, high-precision processing is realized, and the service life of the circuit board is improved. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor based on the drawings shown.

[0025] Figure 1 The process flow diagram of the embodiment of the present application;

[0026] Figure 2 The plane schematic diagram of the through hole plate of the embodiment of the present application;

[0027] Figure 3 The plane schematic diagram of the through groove plate of the embodiment of the present application;

[0028] Figure 4 The plane schematic diagram of the single through groove of the embodiment of the present application;

[0029] Figure 5 The plane schematic diagram of the wet film plate of the embodiment of the present application;

[0030] Figure 6 The plane schematic diagram of the effective half hole plate formed by the embodiment of the present application;

[0031] Figure 7 The plane schematic diagram of the half hole metal plate of the embodiment of the present application;

[0032] Figure 8 The plane schematic diagram of the metallized half hole of the embodiment of the present application.

[0033] Explanation of the drawings:

[0034]

[0035] The objectives, features and advantages of the present application will be further illustrated with reference to the embodiments, with reference to the drawings. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0037] It should be noted that all the directionality indications (such as up, down, left, right, front, back, inside, outside, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directionality indications also change accordingly.

[0038] In addition, the descriptions such as “first”, “second” and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first”, “second” can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of “multiple” is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0039] In addition, the technical solutions of each embodiment of the present application can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the scope of protection claimed by the present application.

[0040] Please refer to Figure 1 , Figure 1 for the process flow of the embodiment of the present application.

[0041] The manufacturing process of the embodiment of the present application includes the implementation of each step process in Figure 1 The following will make further step-by-step description of each step process in Figure 1

[0042] Please refer to Figure 2 , Figure 2 for the plan view of the through-hole plate of the embodiment of the present application.

[0043] ​Step S10:

[0044] The circuit board contains the distributed edge invalid area 1020 in the processing process, drills the through hole 1010 in the design position corresponding to the half hole, forms the through hole plate 10; the part of the through hole 1010 located in the edge invalid area 1020 is the invalid half hole 1010A, and the remaining part is the effective half hole 1010B.

[0045] The embodiment drills the complete through hole 1010 along the forming line 1030 and at the position corresponding to the designed half hole, and then removes a part of the invalid half hole 1010A, so that the machining basis is provided for the through slot 2010 made in the invalid half hole 1010A in the subsequent process, and on the other hand, the direct machining of the effective half hole 1010B is reduced, so that the direct milling of the effective half hole 1010B is effectively avoided, the burr and burr at the top corner position of the effective half hole 1010B are easily caused, and high-precision machining is beneficial to be realized.

[0046] Please refer to Figure 3 , Figure 3 is a plan view of the through slot plate of the embodiment of the application.

[0047] Step S20:

[0048] The through slot 2010 is made in the edge invalid area 1020 along the forming line 1030 for each through hole 1010, the through slot plate 20 is formed, that is, the edge invalid area 1020 is milled from the invalid half hole 1010A to the two opposite directions from inside to outside along the forming line 1030, the through slot 2010 is formed, and the hole is milled from inside to outside, on the one hand, the milling cutter can be closely attached to the hole wall for initial positioning, the milling cutter is tightly wrapped by the plate body, the burr and burr caused by the direct drilling of the half hole are effectively avoided, and on the other hand, the milled flat slot wall also provides a closed space for the subsequent preparation of the wet film layer 3020, which is beneficial to the better combination of the wet film layer 3020 and the metallization layer 3010.

[0049] Please refer to Figure 4 , Figure 4 is a plan view of the single through slot of the embodiment of the application.

[0050] In one embodiment, the through holes 1010 intersect between the through grooves 2010 to form a single through groove 2010A, which on one hand can reduce dead corners and bubbles in the electroplating process, ensure the integrity and uniformity of the metallization layer 3010, reduce electroplating defects, and further provide a flat metallization layer 3010 base for the subsequent preparation of the wet film layer 3020, and on the other hand form a structure that can be cut off from the single through groove 2010A to the edge of the plate, which can cut off the connection between the through groove and the plate surface, and provide a convenient processing base for removing the invalid area 1020 of the plate edge where the invalid half hole 1010A is located.

[0051] Please refer to Figure 5 , Figure 5 for the plan view of the wet film plate of the embodiment of the present application.

[0052] The through holes 1010 and the through grooves 2010 are electroplated to form a metallization layer 3010, and then a wet film layer 3020 covering the metallization layer is prepared, that is, a wet film is coated or silk-screen printed on the area where the through holes 1010 and the through grooves 2010 are located, and then baked and cured to form a wet film layer 3020, thereby forming a wet film plate 30. It is worth noting that the wet film layer 3020 protects the metallization layer 3010 by isolating the etching solution, so that after the wet film is coated, the baking and curing process is directly performed without the need for conventional processes such as developing and exposing.

[0053] To ensure the protective effect of the wet film layer 3020 on the metallization layer 3010, the wet film layer 3020 is prepared by immersing the area where the through holes 1010 and the through grooves 2010 are located in the wet film, then taking it out and standing still, and then baking and curing to form the wet film layer 3020. On one hand, it ensures that the area where the through holes 1010 and the through grooves 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 the embodiment is not used for pattern transfer processing, but provides a greater error tolerance for removing the wet film layer 3020 on the corresponding forming line of the wet film plate 30 by milling in the subsequent process. Therefore, the immersion method is more simple and convenient to operate, and has the beneficial effects of reducing the processing procedures and reducing the production complexity and cost.

[0054] In an embodiment, the wet film coating is multiple coating or silk printing, and each coating or silk printing is followed by baking and curing, i.e. single coating and drying, which is a multiple process. On the one hand, the multiple coating and baking and curing can discharge bubbles layer by layer, avoid defects such as sagging and foaming caused by one-time coating, make the whole wet film layer 3020 more uniform, and thus improve the quality and reliability of the wet film layer 3020. On the other hand, the process has the effect of accelerating the drying and curing of the wet film layer 3020, and enhances the corrosion resistance of the wet film layer 3020, thus forming a good protective effect on the metallized layer 3010.

[0055] In the embodiment, the dry film is attached to the area outside the hole ring of the through hole 1010 and the through groove 2010, and then coating or silk printing is performed. In this way, the wet film coating or silk printing is more concentrated and accurate, and the problem of wet film loss at the edge of the through hole 1010 and the through groove 2010 is prevented. Preferably, silk printing is used for wet film processing.

[0056] Please refer to Figure 6 , Figure 6 is a plan view of an effective half-hole plate formed by the embodiment of the application.

[0057] Further, after the wet film plate 30 is formed, the plate edge invalid area 1020 where the invalid half-hole 1010A is located in the wet film plate 30 is removed to form an effective half-hole plate 40. That is, the through groove 2010 is milled beyond the plate edge invalid area 1020. On the one hand, by milling the plate edge invalid area 1020 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 subsequent formation of a metallized half-hole 6010. On the other hand, compared with the prior art of forming a plate body first and then drilling a half-hole, the effective half-hole 1010B formed by the embodiment has higher precision.

[0058] Please refer to Figure 7 , Figure 7 is a plan view of a half-hole metal plate according to an embodiment of the application.

[0059] Step S30:

[0060] The wet film layer 3020 corresponding to the forming line 1030 of the wet film plate 30 is removed, and then the metallized layer 3010 corresponding to the forming line 1030 is etched to form a half-hole metal plate 50.

[0061] In the embodiment, since the metalized layer 3010 on the corresponding forming line 1030 needs to be etched and removed 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. Unlike the conventional process of removing the wet film layer 3020 using a film stripping solution, the wet film layer 3020 on the corresponding forming line 1030 of the wet film plate 50 is removed by milling, which can selectively control the position and range of the removed wet film layer 3020, ensure that the wet film layer 3020 on the forming line is completely removed, and will not affect the wet film layer 3020 in other areas, forming the effect of selectively removing the wet film layer 3020, so that the exposed metalized layer 3010 provides a processing basis for subsequent etching.

[0062] The embodiment removes the metalized layer 3010 on the corresponding forming line 1030 by chemical etching, which has a higher tolerance for processing errors than the existing technology of directly milling off the metalized layer 3010 of the connecting area between adjacent effective half-holes 1010B by milling, and thus the metalized half-hole 6010 formed by processing has higher precision.

[0063] Please refer to Figure 8 , Figure 8 is a plan view of the metalized half-hole of the embodiment of the present application.

[0064] Step S40:

[0065] The half-hole metal plate 50 is film stripped, the effective half-hole 1010B forms a metalized half-hole 6010, and the circuit board 60 is processed in subsequent processes and forming processes.

[0066] The above description is only a preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation made under the inventive concept of the present application, using the content of the specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A method for manufacturing a circuit board edge metallization half-hole, characterized in that, The manufacturing method comprises the following steps: S10: the circuit board contains a periphery invalid area during processing, and a through hole is drilled at a design position corresponding to the semi-hole to form a through hole plate; The part of the through hole located in the periphery invalid area is an invalid semi-hole, and the remaining part is an effective semi-hole; S20: a through slot is manufactured along a forming line in the periphery invalid area of each through hole, the through hole and the through slot are electroplated to form a metallization layer, and then a wet film layer covering the metallization layer is manufactured to form a wet film plate; After the wet film plate is formed, the periphery invalid area in the wet film plate where the invalid semi-hole is located is removed; the periphery invalid area in the wet film plate where the invalid semi-hole is located is removed by milling from the through slot to outside the periphery invalid area; S30: the wet film layer corresponding to the forming line on the wet film plate is removed, and then the metallization layer corresponding to the forming line is etched to form a semi-hole metal plate; S40: the semi-hole metal plate is subjected to film stripping, and the effective semi-hole forms the metallized semi-hole.

2. The method of claim 1, wherein the step of forming the via comprises the steps of: forming a first via in the first layer of the circuit board; and forming a second via in the second layer of the circuit board, the second via being aligned with the first via. The through slot is manufactured by milling from the invalid semi-hole to the outside of the periphery invalid area in two opposite directions along the forming line in the periphery invalid area.

3. The method of claim 1 or 2, wherein the method further comprises: forming a first metal layer on the first surface of the circuit board; and forming a second metal layer on the second surface of the circuit board. The through slots of adjacent through holes intersect.

4. The method of claim 1, wherein the step of forming a via in the plated edge of the circuit board comprises the steps of: forming a via in the plated edge of the circuit board; and plating the via with a conductive material. 5 The wet film layer is manufactured by coating a wet film on the area where the through hole and the through slot are located, and then baking and curing to form the wet film layer.

5. The method of claim 4, wherein the step of forming a via in the plated edge of the circuit board comprises the steps of: forming a via in the plated edge of the circuit board; and plating the via with a conductive material. 5 The wet film is coated multiple times, and baking and curing are performed after each coating.

6. The method of claim 4, wherein the step of forming a via in the plated edge of the circuit board comprises the steps of: forming a via in the plated edge of the circuit board; and plating the via with a conductive material. Dry film is attached to the area outside the hole ring of the through hole and the through slot, and then the coating process is performed.

7. The method of claim 1, wherein the step of forming a via in the plated edge of the circuit board comprises the steps of: forming a via in the plated edge of the circuit board; and plating the via with a conductive material. 7 The wet film layer is manufactured by immersing the area where the through hole and the through slot are located in a wet film, then taking out and standing, and then baking and curing to form the wet film layer.

8. The method for manufacturing a metallized half hole on a circuit board edge according to claim 1, wherein: The wet film layer corresponding to the forming line on the wet film plate is removed by milling.

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