Molding method of PCB thick-hole copper PTH half hole

Abstract

The embodiment of the invention provides a forming method of a PCB thick-hole copper PTH half hole, and the method comprises the following steps: sequentially carrying out the copper deposition and board power on a substrate which is provided with a pre-drilled hole used as the PTH half hole, so as to respectively form a hole copper layer on the hole wall of the pre-drilled hole and form a surface copper layer on the board surface of the substrate; d / F operation and primary pattern electroplating are sequentially carried out on the substrate on which the hole copper layer and the surface copper layer are obtained, and only the surface of the hole copper layer is further electroplated with copper so as to thicken the hole copper layer to a preset middle thickness; carrying out thickening pattern electroplating on the substrate with the hole copper layer reaching the middle thickness, and respectively thickening the hole copper layer and the surface copper layer to design thickness values to obtain a semi-finished product; cutting grooves are formed in the positions, corresponding to the two opposite side edges of the pre-drilled hole, of the two opposite side plate faces of the semi-finished product through the grooving technology, the depth of the cutting grooves is larger than the thickness of the face copper layer, the portions, on the two corresponding side edges of the pre-drilled hole, of the face copper layer are cut off, and the thick-hole copper PTH half hole is obtained. According to the embodiment of the invention, burrs at the hole opening of the PTH half hole can be effectively removed.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of PCB manufacturing, and in particular, to a forming method for a thick-hole copper PTH half-hole of a PCB. Background Art

[0002] Existing PCB boards usually design PTH half-holes (semi-metallized holes) to achieve interlayer conduction of the PCB board. Currently, with the increasing demand for the precision of PCB boards, the copper layer thickness on the inner wall of the PTH half-holes on the PCB board is getting larger and larger (for example: 139 μm). During the process of forming the PTH half-holes, it is usually necessary to use a drilling process to remove the burrs on the periphery of the hole opening. However, due to the large thickness of the copper layer on the inner wall of the hole, it is usually difficult to effectively remove the burrs through the drilling process, and the copper layer that needs to be retained in the hole is also easily carried out during drilling, affecting the yield of the PTH half-holes. Summary of the Invention

[0003] The technical problem to be solved by the embodiments of the present invention is to provide a forming method for a thick-hole copper PTH half-hole of a PCB, which can effectively remove the burrs at the hole opening of the PTH half-hole.

[0004] To solve the above technical problem, the embodiments of the present invention provide the following technical solutions: A forming method for a thick-hole copper PTH half-hole of a PCB, comprising the following steps: Carry out electroless copper plating and panel electroplating on the substrate processed to form a pre-drilled hole for the PTH half-hole in sequence, so as to form a hole copper layer on the hole wall of the pre-drilled hole and a surface copper layer on the surface of the substrate respectively; Carry out D / F operation and primary pattern electroplating on the substrate obtained with the hole copper layer and the surface copper layer in sequence, and only electroplate copper on the surface of the hole copper layer further to thicken the hole copper layer to a preset intermediate thickness; Carry out thickening pattern electroplating on the substrate with the hole copper layer reaching the intermediate thickness, and thicken the thicknesses of the hole copper layer and the surface copper layer to the designed thickness values respectively to obtain a semi-finished product; and Adopt a grooving process to form cut grooves at positions corresponding to the opposite sides of the pre-drilled hole on the opposite sides of the semi-finished product respectively, and the depth of the cut grooves is greater than the thickness of the surface copper layer to cut off the surface copper layer at the opposite sides of the pre-drilled hole to obtain a thick-hole copper PTH half-hole.

[0005] Further, the grooving process is a VCUT process or a routing process.

[0006] Further, the pre-drilled hole is a strip-shaped hole, and the grooving process is to cut the surface copper layer on the two opposite sides of the PCB along a vertical plane perpendicular to the length direction central axis of the strip-shaped hole on the two opposite sides of the PCB respectively to form the cut grooves.

[0007] Further, the PCB is a mother board of a PCB having a plurality of PCB sub-board units, and one of the strip holes is formed corresponding to each PCB sub-board unit, and each of the strip holes straddles the corresponding boundary inside and outside of one of the PCB sub-board units and the length direction of the strip hole is perpendicular to the boundary.

[0008] Further, the thickened pattern electroplating process is performed at least twice, and after the first thickened pattern electroplating, D / F operation is first performed to form a predetermined pattern circuit on the surface copper layer, and then the second thickened pattern electroplating is performed.

[0009] Further, after the cut groove is formed, an etching process is further performed, and the cut groove is inspected after the etching process to ensure that the copper connection at the cut groove is etched off.

[0010] Further, after the initial pattern electroplating is completed, the orifice of the pre-drilled hole is polished to remove the protruding copper before performing the thickened pattern electroplating.

[0011] After adopting the above technical solution, the embodiment of the present invention has at least the following beneficial effects: After the embodiment of the present invention first performs copper deposition and panel electroplating on the substrate to form a hole copper layer on the hole wall of the pre-drilled hole and a surface copper layer on the panel surface of the substrate, through further D / F operation and initial pattern electroplating on the substrate, copper is only further electroplated on the surface of the hole copper layer to thicken the hole copper layer, and then further thickened pattern electroplating is performed to thicken the hole copper layer and the surface copper layer respectively, ensuring that the thickness of the hole copper layer on the hole wall of the pre-drilled hole and the surface copper layer on the PCB panel surface can reach the designed thickness value. Finally, a cut groove is formed at the positions on the opposite sides of the pre-drilled hole by using a grooving process. Since the depth of the cut groove is greater than the thickness of the surface copper layer, the processed cut groove can effectively cut off the surface copper layer at the corresponding two sides of the pre-drilled hole, and finally a PCB with a thick hole copper PTH half hole can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a step flow chart of an optional embodiment of the method for forming a thick hole copper PTH half hole of the PCB of the present invention.

[0013] Figure 2 It is a cross-sectional schematic view of the PCB after step S1 of an optional embodiment of the method for forming a thick hole copper PTH half hole of the PCB of the present invention.

[0014] Figure 3 It is a cross-sectional schematic view of the PCB after step S2 of an optional embodiment of the method for forming a thick hole copper PTH half hole of the PCB of the present invention.

[0015] Figure 4 It is a cross-sectional schematic view of the PCB after step S3 of an optional embodiment of the method for forming a thick hole copper PTH half hole of the PCB of the present invention.

[0016] Figure 5 Schematic diagram of the PCB board surface after step S4 in an alternative embodiment of the forming method of the thick hole copper PTH half hole of the present invention.

[0017] Figure 6 Cross-sectional schematic diagram of the PCB after step S4 in an alternative embodiment of the forming method of the thick hole copper PTH half hole of the present invention. Detailed implementation manners

[0018] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the following illustrative embodiments and descriptions are only used to explain the present invention and are not intended to limit the present invention. Moreover, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0019] As Figure 1 shown, an alternative embodiment of the present invention provides a forming method for a PCB high aspect ratio PTH half hole, including the following steps: S1: The substrate 1 processed with the pre-drilled hole 10 used as the PTH half hole is sequentially subjected to electroless copper plating and panel electroplating to form a hole copper layer 12 on the hole wall of the pre-drilled hole 10 and a surface copper layer 14 on the board surface of the substrate 1, as Figure 2 shown; S2: The substrate 1 obtained with the hole copper layer 12 and the surface copper layer 14 is sequentially subjected to D / F operation and primary pattern electroplating, and only copper is further electroplated on the surface of the hole copper layer 12 to thicken the hole copper layer 12 to a preset intermediate thickness, as Figure 3 shown; S3: The substrate 1 with the hole copper layer 12 reaching the intermediate thickness is subjected to thickening pattern electroplating to thicken the thicknesses of the hole copper layer 12 and the surface copper layer 14 to the designed thickness values respectively to obtain a semi-finished product, as Figure 4 shown; and S4: The grooving process is used to form cut grooves 16 at positions corresponding to the opposite sides of the pre-drilled hole 10 on the opposite sides of the board surface of the semi-finished product. The depth of the cut grooves 16 is greater than the thickness of the surface copper layer 14 to cut off the surface copper layer 14 at the corresponding opposite sides of the pre-drilled hole 10 to obtain a thick hole copper PTH half hole, as Figures 5 - 6 shown.

[0020] In the embodiment of the present invention, after performing electroless copper plating and panel plating on the substrate 1 to form a hole copper layer 12 on the hole wall of the pre-drilled hole 10 and a surface copper layer 14 on the surface of the substrate 1, through further D / F operation and primary pattern electroplating on the substrate 1, copper is further electroplated only on the surface of the hole copper layer 12 to thicken the hole copper layer 12, and then through further thickening pattern electroplating, the hole copper layer 12 and the surface copper layer 14 are thickened respectively, ensuring that the thickness of the hole copper layer 12 on the hole wall of the pre-drilled hole 10 and the surface copper layer 14 on the PCB surface can reach the designed thickness value. Finally, a grooving process is used to form a cut groove 16 at the positions on the opposite sides of the pre-drilled hole 10. Since the depth of the cut groove 16 is greater than the thickness of the surface copper layer 14, the processed cut groove 16 can effectively cut off the surface copper layer 14 at the corresponding two sides of the pre-drilled hole 10, and finally a PCB with a thick hole copper PTH half hole can be obtained.

[0021] In an alternative embodiment of the present invention, the grooving process is a VCUT process or a routing process. In this embodiment, both the VCUT process and the routing process are common grooving processes in the PCB processing, which can effectively process cut grooves on the PCB. In specific implementation, the grooving process can also adopt methods such as drilling grooving and laser grooving. In the figure In an alternative embodiment of the present invention, the pre-drilled hole 10 is a strip hole, and the grooving process is to perform cutting on the vertical planes perpendicular to the central axis of the length direction of the strip hole on the opposite two side plates of the PCB to cut off the surface copper layer 14 on the two side plates of the PCB respectively to form the cut groove 16. In this embodiment, by processing the cut groove 16 in the above manner, it can ensure that the surface copper layer 14 on the PCB surface is cut off.

[0022] In an alternative embodiment of the present invention, as Figure 5 shown, the PCB is a PCB mother board having a plurality of PCB sub-board units 18. A corresponding strip hole is formed for each PCB sub-board unit 18, and each strip hole straddles the corresponding boundary 181 inside and outside of a corresponding PCB sub-board unit 18 and the length direction of the strip hole is perpendicular to the boundary 181. In this embodiment, through the above settings, after forming the cut groove 16, not only can the surface copper layer 14 on both sides of the pre-drilled hole 10 be cut off to form a PTH half hole; but also in the PCB processing, usually multiple PCB sub-board units 18 are designed on a PCB mother board, each PCB sub-board unit 18 corresponds to a PCB sub-board, and a corresponding PTH half hole needs to be designed on each PCB sub-board. Therefore, when processing the cut groove 16, the panel splitting process of the PCB board can also be realized by using the processed cut groove 16. It can be understood that since the surface copper layer 14 on both sides of the pre-drilled hole is cut off after the cut groove 16, when splitting the board along the cut groove 16 in the subsequent panel splitting process, that is, only one end of the strip hole will be located inside the PCB sub-board unit 18.

[0023] In an alternative embodiment of the present invention, the thickened pattern electroplating process is performed at least twice. After the first thickened pattern electroplating, D / F operation is first carried out to form a predetermined pattern circuit on the surface copper layer, and then the second thickened pattern electroplating is carried out. In this embodiment, in order to make the copper layer thickness of the hole wall of the pre-drilled hole 10 reach the aforementioned designed thickness value (for example: 137 - 141 μm, preferably 139 μm), the copper layer thickness formed by a single thickened pattern electroplating process usually cannot meet the requirement, so two consecutive thickened pattern electroplating processes are needed.

[0024] In an alternative embodiment of the present invention, after the cut groove is formed, an etching process is also carried out, and the cut groove is inspected after the etching process to ensure that the copper connection at the cut groove is etched off. In this embodiment, in the subsequent etching process of the PCB, the burrs at the cut groove opening can also be etched away; and the cut groove is inspected after the etching process to ensure that the copper connection at the cut groove is etched off, ensuring that the copper layer at the cut groove is effectively cut off and avoiding residues.

[0025] In an alternative embodiment of the present invention, after the initial pattern electroplating is completed, the pre-drilled hole opening is polished to remove the protruding copper before the thickened pattern electroplating is carried out. In this embodiment, after the thickened hole copper layer is formed by the initial pattern electroplating, the protruding copper at the opening of the pre-drilled hole 10 is polished to remove the protruding copper layer at the hole opening, thereby avoiding the copper layer protrusion at the opening of the pre-drilled hole 10 and affecting the yield of the formed PTH half-hole.

[0026] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the spirit and scope protected by the claims of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A forming method for PCB thick-hole copper PTH half-holes, characterized in that, The method comprises the following steps: Performing electroless copper plating and panel plating on the substrate with the pre-drilled holes used as PTH half-holes in sequence to form a hole copper layer on the hole walls of the pre-drilled holes and a surface copper layer on the surface of the substrate respectively; Performing D / F operation and primary pattern plating on the substrate with the hole copper layer and the surface copper layer obtained in sequence, and only electroplating copper on the surface of the hole copper layer to thicken the hole copper layer to a preset intermediate thickness; Performing thickening pattern plating on the substrate with the hole copper layer reaching the intermediate thickness to thicken the thicknesses of the hole copper layer and the surface copper layer to the designed thickness values respectively to obtain a semi-finished product; and Adopting a grooving process to form cut grooves at positions corresponding to the opposite sides of the pre-drilled holes on the opposite side surfaces of the semi-finished product, wherein the depth of the cut grooves is greater than the thickness of the surface copper layer to cut off the surface copper layer at the opposite sides of the pre-drilled holes to obtain a thick-hole copper PTH half-hole.

2. The forming method of the PCB thick-hole copper PTH half-hole according to claim 1, characterized in that, The grooving process is a VCUT process or a routing process.

3. The forming method of the PCB thick-hole copper PTH half-hole according to claim 1 or 2, characterized in that, The pre-drilled holes are strip-shaped holes, and the grooving process is to cut the surface copper layer on the two side surfaces of the PCB along a vertical plane perpendicular to the central axis of the length direction of the strip-shaped holes on the opposite side surfaces of the PCB to form the cut grooves respectively.

4. The forming method of the PCB thick-hole copper PTH half-hole according to claim 3, characterized in that, The PCB is a PCB mother board having a plurality of PCB sub-board units, and one of the strip-shaped holes is formed corresponding to each PCB sub-board unit, and each strip-shaped hole straddles the inside and outside of the corresponding boundary of one PCB sub-board unit and the length direction of the strip-shaped hole is perpendicular to the boundary.

5. The forming method of the PCB thick-hole copper PTH half-hole according to claim 1, characterized in that, The thickening pattern plating process is performed at least twice, and after the first thickening pattern plating, a D / F operation is first performed to form a predetermined pattern circuit on the surface copper layer, and then the second thickening pattern plating is performed.

6. The forming method of the PCB thick-hole copper PTH half-hole according to claim 1, characterized in that, After the cut grooves are formed, an etching process is also performed, and the cut groove portion is inspected after the etching process to ensure that the copper connection at the cut groove portion is etched off.

7. The forming method of the PCB thick-hole copper PTH half-hole according to claim 1, characterized in that, After the primary pattern plating is completed, the hole opening of the pre-drilled hole is polished to remove the protruding copper before the thickening pattern plating is performed.

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