Manufacturing method of very-large-current printed circuit board

Abstract

The invention provides a manufacturing method of a very large current printed circuit board. According to the method, based on a high-thickness copper foil or a copper plate, a circuit is manufactured through a machining or laser processing method according to design requirements, then the circuit, a prepreg, an insulating layer of a reserved window and the like are laminated in a laminating mode, and integration of a very-large-current circuit and a printed circuit board is achieved. The method can be used for manufacturing a high-thickness copper circuit, can realize very accurate circuit size control, and is particularly suitable for manufacturing thick copper circuits, especially thick copper circuits of more than 10OZ.

Description

Technical Field

[0001] The invention belongs to the technical field of printed circuit manufacturing, and relates to very high current printed circuit board products used in fields such as new energy vehicles. Technical Background

[0002] As the voltage of new energy vehicles continues to increase, the current carrying capacity is also constantly improving. The current carrying capacity of more than 300A has begun to be designed in the field of new energy vehicles. The use of printed circuit boards for the transmission of very large currents can not only facilitate the installation of high-power control devices, but also facilitate the heat dissipation of control modules. The common practice of making high-current printed circuit boards is to use high-thickness copper for multiple etchings or selective etching to make current-carrying copper lines.

[0003] Symmetric etching of the front and back surfaces, that is, half of the thick copper is etched by half etching on the front side, and then lamination is performed, and the copper layer on the back side is symmetrically etched, etc., which can effectively reduce the side etching problem and achieve circuit compensation to a certain extent. However, copper circuits thicker than 10OZ not only take a long time to etch, but also have particularly severe side etching. Symmetric etching of the front and back surfaces still seriously affects the design size of the circuit.

[0004] Selective etching can effectively reduce side etching. However, when the copper is too thick, the long spraying process causes the copper foil on the side to still have serious side corrosion under the protection of the corrosion inhibitor as soon as possible, which leads to its application range being lower than 5OZ copper circuit etching.

[0005] To this end, the present invention proposes a method for manufacturing a very high current printed circuit board, which performs high-precision molding and manufacturing for copper circuits of 10OZ or even thicker. The method uses laser processing or mechanical processing to remove the copper circuit, and then integrates the circuit with the printed circuit board by embedding to meet the application requirements of very high current transmission. Summary of the invention

[0006] The present invention proposes a method for manufacturing a high-thickness copper printed circuit board in response to the very large current transmission requirements of new energy vehicles. The method manufactures high-thickness circuits by laser processing or mechanical processing, avoiding the side erosion problem caused by conventional printed circuit board etching, and does not require compensation design for the circuit, thus simplifying the method for manufacturing the circuit.

[0007] The present invention provides a method for manufacturing a very high current printed circuit board. The printed circuit board conductor is based on high-thickness copper foil or copper plate, and the circuit is manufactured by mechanical processing or laser processing according to design requirements, and then the circuit is pressed with a prepreg, an insulating layer with a reserved window, etc. by lamination to achieve the integration of the very high current circuit and the printed circuit board.

[0008] In the present invention, the copper circuit is processed as an independent line, and each interconnection circuit is processed into a separate part. Copper foil or copper plate can be used, depending on the required copper thickness. The present invention is particularly suitable for the production of high current, high thickness copper, especially more than 10OZ circuits.

[0009] Before lamination, the copper circuit needs to be browned or roughened to improve the bonding strength between the copper circuit and the copper clad laminate prepreg and insulating material. At the same time, windows for the copper circuit need to be reserved for the prepreg, dielectric insulating layer, etc. to facilitate the embedding of the copper circuit.

[0010] Before lamination, a release film is needed to seal the lower end of the line width so that the copper line is not easily offset during the lamination process.

[0011] After lamination, "glue overflow" is likely to occur, and plasma or grinding is required to remove the glue overflow from the lamination to obtain a clean copper surface. At the same time, the quality inspection requires that the flatness error of the circuit is less than 25μm.

[0012] In addition to being applicable to copper circuits, this method is also applicable to the processing of other metal materials used to carry current, but a matching surface treatment method is required to enhance the bonding force with the prepreg or insulating dielectric layer.

[0013] High-thickness copper circuits made by mechanical processing or laser processing methods can achieve very precise dimensional control, and their dimensional error is much lower than that of etching methods. They are particularly suitable for thick copper, especially thick copper circuit production, to meet the growing charging or current-carrying needs of new energy vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an independent circuit part processed by laser or machine;

[0015] Figure 2 A structural diagram of a laminated dielectric layer using prepregs;

[0016] Figure 3 This is a structural diagram of the copper circuit window reserved after the prepreg is laminated;

[0017] Figure 4 This is a structural diagram formed after lamination of copper circuit and prepreg; Specific implementation plan

[0018] Three lines with a width of 0.8 cm and a length of 13 cm were milled out on the 0.75 mm thick copper sheet by mechanical milling. The lines were also treated with browning to improve the bonding strength between them and the semi-curing process in the subsequent process, thus ensuring the reliability of the lines.

[0019] Ten 1080-model prepreg sheets were pre-laminated, and three lines of integrated windows were milled out using a milling cutter in preparation for lamination.

[0020] The bottom window of the semi-cured sheet is sealed with release paper, the copper circuit is placed in the window, and the laminator is used to laminate it. The lamination parameters are set according to the curing conditions of 1080 semi-cured.

[0021] The laminated board is polished until all the overflow glue is polished away, and then roughened for the next solder mask process.

Claims

1. A method for manufacturing a very high current printed circuit board, characterized in that: The design requires that the circuit be produced by mechanical processing or laser processing, and then the circuit is pressed together with the semi-cured sheet, the insulating layer with the reserved window, etc. by lamination to achieve the integration of the very high current circuit and the printed circuit board.

2. The laser processing circuit process according to claim 1, characterized in that: The circuits are processed as independent lines, and each interconnecting circuit is processed as a separate part.

3. The laminated circuit according to claim 1, characterized in that: Before lamination, the copper circuit needs to be browned or roughened to improve the bonding strength between the circuit and the prepreg and insulating material.

4. The reserved window according to claim 1 can be a prepreg material or a cured insulating dielectric layer.

5. The lamination process according to claim 1, characterized in that: After lamination, the "glue overflow" phenomenon is removed by plasma or grinding to obtain a clean metal surface.

6. The circuit according to claim 1 can be made of copper or other metals.

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