A process for preparing thick copper circuits on a PCB board

Abstract

The present invention discloses a process method for preparing a thick copper circuit on a PCB board, which can reduce the copper consumption during the processing of the thick copper circuit on the PCB board. The method includes the following steps: S1. Select a copper-clad laminate with single-sided or double-sided basic copper as the base material, and cover an auxiliary material on the surface of the copper-clad laminate; S2. Form a circuit pattern on the auxiliary material as required. The circuit pattern exists in a hollowed-out form in the auxiliary material, and the auxiliary material is divided into a circuit pattern auxiliary material and other auxiliary materials. The circuit pattern auxiliary material corresponds to the thick copper circuit on the PCB board; S3. Remove the circuit pattern auxiliary material, and prepare thick copper at the part of the base material other than the part covered by the other auxiliary materials; S4. Remove the other auxiliary materials, thereby exposing the basic copper to be removed, and then remove the basic copper to be removed. The process method of the present invention avoids etching thick copper and only needs to etch a small amount of basic copper on the surface of the base material, so it can greatly reduce the waste of copper and reduce the cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic component processing, and more specifically, relates to a process method for preparing thick copper circuits on a PCB board. Background Art

[0002] With the development of technology, people have an increasingly high demand for electronic products with high performance, multiple functions, and the ability to carry large currents. Therefore, the demand for thick copper circuit boards is also increasing day by day.

[0003] For the processing of thick copper circuit boards, currently in the industry, the laminated method with electroplated copper deposition for successive thickening followed by multiple solder mask printing assistance is generally used, or the manufacturing of ultra-thick copper printed circuit boards is achieved by using ultra-thick copper foil through an etching process. For the incoming copper, the thicker the copper thickness, the more copper is wasted due to etching. And the above two commonly used methods in the industry will waste a lot of copper in the etching process. Therefore, it is necessary to improve the preparation process of thick copper circuits to reduce waste and lower costs.

[0004] It should be noted that the information disclosed in the above background art section is only for understanding the background of the present application, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0005] To overcome the defects of the aforementioned prior art, the embodiments of the present application provide a process method for preparing thick copper circuits on a PCB board, which can reduce the copper consumption during the processing of thick copper circuits on the PCB board, and includes the following steps:

[0006] S1. Select a copper-clad laminate with single-sided or double-sided base copper as the substrate, and cover an auxiliary material on the surface of the copper-clad laminate;

[0007] S2. Form a circuit pattern on the auxiliary material as needed. The circuit pattern exists in the form of a hollow in the auxiliary material, and the auxiliary material is divided into a circuit pattern auxiliary material and other auxiliary materials. The circuit pattern auxiliary material corresponds to the thick copper circuit on the PCB board;

[0008] S3. Remove the circuit pattern auxiliary material, and prepare thick copper at the positions of the substrate other than those covered by the other auxiliary materials;

[0009] S4. Remove the other auxiliary materials, thereby exposing the base copper to be removed, and then remove the base copper to be removed.

[0010] The embodiments of the present invention may also adopt the following preferred or alternative solutions:

[0011] Before step S4 and after step S3, a protective tin layer is also plated on the thick copper surface.

[0012] The thickness of the thick copper prepared in step S3 is smaller than the thickness of the auxiliary material.

[0013] In step S3, the thickness of the thick copper is ≥140 μm, and the thickness of the thick copper is at least 5 μm smaller than the thickness of the auxiliary material.

[0014] In step S3, the etching factor of the thick copper is ≥5.

[0015] In step S4, the base copper to be removed is removed by an etching method or a mechanical removal method.

[0016] In step S1, before covering the auxiliary material on the surface of the copper clad laminate, a through hole is also opened at a predetermined position of the base material, and the through hole is flash plated so that a flash plating layer adheres to the surface of the through hole.

[0017] Step S3 is: first, a removal handle is set on the circuit pattern auxiliary material, and then the circuit pattern auxiliary material is removed through the removal handle.

[0018] The setting of the removal handle is achieved by laser welding a waste discharging adhesive tape on the circuit pattern auxiliary material or by laminating a waste discharging adhesive tape on the circuit pattern auxiliary material.

[0019] The base copper on the copper clad laminate is thin copper with a thickness of ≤17.5 μm; the auxiliary material is a black PET film with a thickness of 0.25 mm and a viscosity of 300 g; the waste discharging adhesive tape has a light transmittance greater than 40%, a thickness of 0.1 mm, and a viscosity of 0.

[0020] One or more technical solutions provided in the embodiments of the present application have at least the following beneficial effects compared with the prior art:

[0021] The process method of the present invention avoids etching thick copper and only needs to etch a small amount of base copper on the base material, so it can avoid or greatly reduce the waste of copper and reduce the cost.

[0022] By setting a removal handle on the auxiliary material, the auxiliary material can be removed more conveniently, efficiently, at low cost and thoroughly, simplifying the processing technology and improving the efficiency. Brief Description of the Drawings

[0023] Figure 1 is a schematic cross-sectional structure diagram of the copper clad laminate according to the embodiment of the present invention;

[0024] Figure 2 is a schematic cross-sectional structure diagram of the copper clad laminate after punching according to the embodiment of the present invention;

[0025] Figure 3 is a schematic cross-sectional structure diagram of the copper clad laminate after flash plating according to the embodiment of the present invention;

[0026] Figure 4 It is a schematic cross-sectional structure diagram of the copper clad laminate after covering auxiliary materials on both the front and back sides in the embodiment of the present invention;

[0027] Figure 5 It is a schematic cross-sectional structure diagram of the copper clad laminate covered with auxiliary materials after laser cutting the circuit route;

[0028] Figure 6 It is a schematic cross-sectional structure diagram of the copper clad laminate after pasting waste discharge adhesive paper on both the front and back sides in the embodiment of the present invention;

[0029] Figure 7 It is a schematic cross-sectional structure diagram of the copper clad laminate after welding the waste discharge adhesive paper and the circuit pattern auxiliary material on the copper clad laminate in the embodiment of the present invention;

[0030] Figure 8 It is a schematic cross-sectional structure diagram of the copper clad laminate after tearing off the waste discharge adhesive paper in the embodiment of the present invention;

[0031] Figure 9 It is a schematic cross-sectional structure diagram of the copper clad laminate after thickening the copper on the circuit pattern in the embodiment of the present invention;

[0032] Figure 10 It is a schematic cross-sectional structure diagram of the copper clad laminate after plating a tin layer on the surface of the thick copper in the embodiment of the present invention;

[0033] Figure 11 It is a schematic cross-sectional structure diagram of the copper clad laminate covered with auxiliary materials after tearing off the remaining other auxiliary materials in the embodiment of the present invention;

[0034] Figure 12 It is a schematic cross-sectional structure diagram of the copper clad laminate after etching the base copper in the embodiment of the present invention;

[0035] Figure 13 It is a process flow block diagram of an embodiment of the present invention. Detailed implementation manners

[0036] The following further describes the present invention in conjunction with the attached Figures 1-13 drawings and specific implementation manners, where the same reference numerals represent the same components, unless otherwise specified. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope of the present invention and its applications.

[0037] Embodiment 1

[0038] This embodiment provides a process method for preparing a thick copper circuit of a PCB board, and its process flow is as Figure 13 shown, including the following steps:

[0039] S1. Select a copper clad laminate as the base material 1, and cover auxiliary material 2 on the surface of the copper clad laminate. As Figure 1As shown, the double-sided copper-clad laminate has a base copper layer 5 on both sides. Preferably, before covering the auxiliary material 2 on the surface of the copper-clad laminate, through holes 8 are also opened at predetermined positions on the substrate 1. After opening the through holes 8, as Figure 2 shown, and flash plating treatment is performed on the through holes 8 so that a flash plating layer 9 adheres to the surface of the through holes 8, as Figure 3 shown. After the substrate 1 is provided with through holes 8, flash plating treatment and covered with the auxiliary material 2, as Figure 4 shown. The copper-clad laminate can be directly prepared by the full-addition method by depositing copper on the dielectric layer. In this embodiment, the thickness of the base copper layer 5 is 17.5 μm. Obviously, it is not limited thereto, but can be selected from thin copper with a thickness ≤ 17.5 μm. The auxiliary material 2 can be a common auxiliary material such as a PET film. Preferably, the auxiliary material 2 is a black PET film with a thickness of 0.25 mm and a viscosity of 300 g.

[0040] S2. Form a circuit pattern on the auxiliary material 2 as required. The circuit pattern can be freely designed according to requirements, as Figure 5 shown. The circuit pattern divides the auxiliary material 2 into a circuit pattern auxiliary material 6 and other auxiliary materials. The circuit pattern auxiliary material 6 corresponds to the thick copper circuit of the PCB board. The circuit pattern exists in a hollowed-out form in the circuit pattern auxiliary material 6. There are various ways of hollowing out. For example, the circuit pattern can be formed by laser cutting on the circuit pattern auxiliary material 6, or a waste removal handle can be welded on the circuit pattern auxiliary material 6 by laser welding, and then the circuit pattern auxiliary material 6 is removed through the waste removal handle to obtain the circuit pattern.

[0041] S3. Remove the circuit pattern auxiliary material 6 and prepare a thick copper layer 4 at the position outside the substrate 1 covered by the remaining other auxiliary materials. Specifically, a waste removal handle can be first set on the circuit pattern auxiliary material 6, and then the circuit pattern auxiliary material 6 is removed through the waste removal handle. The waste removal handle can be formed by pasting a waste removal adhesive tape 7 on the circuit pattern auxiliary material 6, as Figure 6 shown, or it can also be formed by laser welding a waste removal adhesive tape 7 on the circuit pattern auxiliary material 6, as Figure 7 shown (the black color blocks in the figure are solder joints 67), as long as the combination between the waste removal handle and the circuit pattern auxiliary material 6 is firm enough. Preferably, the light transmittance of the waste removal adhesive tape 7 is greater than 40%, the thickness is 0.1 mm, and the viscosity is 0. As Figure 8 shown, it is a cross-sectional structure schematic diagram after the waste removal adhesive tape 7 and the circuit pattern auxiliary material 6 are torn off through the waste removal handle. The waste removal handle in steps S2 and S3 refers to the waste removal adhesive tape 7 welded or adhered to the target to be torn off.

[0042] The preparation method of the thick copper 4 can adopt methods such as electroplating long copper. After step S3, thick copper 4 is grown at the part outside the substrate 1 covered by the remaining other auxiliary materials. After growing the thick copper 4, as Figure 9 shown. Preferably, the thickness of the thick copper 4 is 140 μm or more, and the thickness of the thick copper 4 is at least 5 μm smaller than the thickness of the auxiliary material 2 to prevent the surface of the thick copper 4 from exceeding the surface of the auxiliary material 2 and causing problems such as deformation of the thick copper circuit. In addition, the etching factor of the thick copper 4 is preferably ≥5.

[0043] S4. Remove the remaining circuit pattern auxiliary material after step S3, thereby exposing the base copper 5 to be removed, and then remove the base copper 5 to be removed.

[0044] In this embodiment, before removing the remaining other auxiliary materials, a protective tin layer 10 is first plated on the surface of the thick copper 4, as Figure 10 shown, which is a cross-sectional structure schematic diagram after plating the tin layer 10 on the surface of the thick copper 4. The method of removing the remaining other auxiliary materials after step S3 can be the same as the removing method in the aforementioned step S3. The base copper 5 can be removed by etching. As Figure 11 shown, which is a cross-sectional structure schematic diagram after removing the remaining other auxiliary materials after step S3. As Figure 12 shown, which is a cross-sectional structure schematic diagram after etching and removing the base copper 5 exposed outside on the copper clad laminate.

[0045] In this embodiment, only a small amount of the base copper 5 needs to be etched and removed, and there is no need to etch the thick copper 4 prepared in step S3. Therefore, the wasted copper during etching is very small. Compared with the prior art, the waste can be greatly reduced and the cost can be lowered.

[0046] Embodiment 2

[0047] The difference between this embodiment and Embodiment 1 above is only that the substrate 1 is a copper clad laminate with a single-sided base copper.

[0048] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, they can also make several substitutions or modifications to these described embodiments, and these substitution or modification methods should all be regarded as belonging to the protection scope of the present invention. In the description of this specification, the descriptions referring to terms such as "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. Without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the scope of protection of the patent application.

Claims

1. A process for preparing a thick copper circuit on a PCB board, characterized in that, It includes the following steps: S1. Select a copper clad laminate with single-sided or double-sided copper as the base material, and cover an auxiliary material on the surface of the copper clad laminate; S2. Form a circuit pattern on the auxiliary material as required. The circuit pattern exists in a hollowed-out form in the auxiliary material, and the auxiliary material is divided into a circuit pattern auxiliary material and other auxiliary materials. The circuit pattern auxiliary material corresponds to the thick copper circuit of the PCB board; S3. Remove the circuit pattern auxiliary material, and prepare thick copper at the position outside the base material covered by the other auxiliary materials. The thickness of the thick copper prepared in step S3 is smaller than the thickness of the auxiliary material. The thickness of the thick copper is ≥140 μm, and the thickness of the thick copper is at least 5 μm smaller than the thickness of the auxiliary material to prevent the surface of the thick copper from exceeding the surface of the auxiliary material and causing deformation of the thick copper circuit. Among them, a tearing handle is first set on the circuit pattern auxiliary material, and then the circuit pattern auxiliary material is removed through the tearing handle. The setting of the tearing handle is achieved by laser welding a waste discharging adhesive tape on the circuit pattern auxiliary material or pasting a waste discharging adhesive tape on the circuit pattern auxiliary material; S4. Remove the other auxiliary materials, thereby exposing the base copper to be removed, and then remove the base copper to be removed.

2. The process method according to claim 1, characterized in that, After step S3 and before step S4, a protective tin layer is also plated on the surface of the thick copper.

3. The process method according to claim 1, characterized in that, In step S3, the etching factor of the thick copper is ≥5.

4. The process method according to claim 1, characterized in that, In step S4, the base copper to be removed is removed by an etching method.

5. The process method according to claim 1, characterized in that, In step S1, before covering the auxiliary material on the surface of the copper clad laminate, through holes are also opened at predetermined positions of the base material, and flash plating treatment is performed on the through holes so that a flash plating layer adheres to the surface of the through holes.

6. The process method according to any one of claims 1-5, characterized in that, The base copper on the copper clad laminate is thin copper with a thickness of ≤17.5 μm; The auxiliary material is a black PET film with a thickness of 0.25 mm and a viscosity of 300 g; The waste discharging adhesive tape has a light transmittance greater than 40%, a thickness of 0.1 mm, and a viscosity of 0.

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