Circuit board manufacturing method and circuit board

Abstract

The invention discloses a circuit board manufacturing method. By means of the method, heavy copper circuit boards with any copper thickness can be manufactured, etching is not needed, and multiple defects of a traditional etching process are overcome. The embodiment of the invention further provides a corresponding circuit board. The method comprises the steps of machining circuit grooves in an insulating board, filling the circuit grooves with liquid metal, solidifying the liquid metal, and forming a circuit layer buried in the insulating board.

Description

technical field [0001] The invention relates to the technical field of circuit boards, in particular to a circuit board manufacturing method and the circuit board. Background technique [0002] As the demand for thick copper circuit boards to carry large currents has become more and more clear, thick copper circuit boards with a current carrying requirement of more than 500A have begun to be used. In order to meet the dual requirements of current carrying and heat dissipation, the thickness of the copper layer must be increased within the limited space of the circuit board. At present, circuit boards with a copper layer thickness exceeding 1 mm have begun to appear. [0003] In the prior art, thick copper circuit boards are generally made by etching both sides of the thick copper board and then pressing the prepreg (ie, PP sheet) together. However, this process has the following defects: due to the deep etching depth, the shoulders of the lines formed by etching will form p...

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Problems solved by technology

However, this process has the following defects: due to the deep etching depth, the shoulders of the lines formed by etching will form peaks, so in the subsequent pressing step, the adhesive material of the PP sheet will flow into the grooves in the gaps between the lines, and the peaks of the line shoulders will It will come into contact with the glass fiber material in the prepreg and cause the glass fiber material to crack or break due to extrusion, affecting product reliability

However, this process also has some defects, including: when filling the resin, a large number of air bubbles will be brought in, resulting in delamination and explosion during lamination; even if there is no explosion, the printed resin will cause the hardness of the circuit board to be very high. Large, adding difficulty to the subsequent drilling process

[0005] In addition, when the etching depth is deep, multi-layer PP sheets need to be arranged during lamination, but when the number of layers of PP sheets is large, the board thickness will be uneven, and as the copper thickness increases, the unevenness of the board thickness will also increase. increase, which in turn will cause the film to be weak when pasting the film on the outer picture, resulting in an open circuit of the outer circuit gap

[0006] Finally, with the increase of copper thickness, especially when the copper thickness exceeds 1mm, the use of traditional etching process to make graphics can no longer meet the requirements of graphics production, because of the existence of side etching, or the cross-sectional area of ​​the actual current-carrying line will be greatly reduced , resulting in severe heating of the lines carrying large currents, causing the circuit board to fail to work normally; or, when the copper layer is too thick, under the serious influence of side corrosion, it is even impossible to etch the required lines

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