A printed circuit board and its processing method

Abstract

The invention discloses a printed circuit board and a processing method of the printed circuit board. The processing method comprises a first step of conducting lightproof, partial transmitting and full transmitting exposure treatment on dry film of a circuit area, dry film of an adjacent area and dry film of a peripheral area which are arranged on the surface of copper foil respectively, a second step of fully dissolving the dry film of the circuit area and forming a circuit on the circuit area by means of two-time developing in sequence, a third step of dissolving a part of dry film arranged on the adjacent area and remaining a dry film layer, a fourth step of wrapping the surface of the circuit with a circuit protective layer. Therefore, circuit protective layers cover the upper surface and the side surface of the circuit. The printed circuit board and the processing method of the printed circuit board have the advantages that when a follow-up etching technology is conducted, the circuit protective layer formed in all surfaces of the circuit can conduct multi-dimensional surface protection on the circuit, the phenomenon of lateral erosion is avoided, the higher quality on the aspects of the circuit width, etching factors and the precision of impendance of the printed circuit board circuit is guaranteed, and conduction and the precision of transmission of the circuit are ensured, especially for a high-precision printed circuit board plate, the advantages are more remarkable.

Description

technical field [0001] The invention relates to the field of printed circuit boards, in particular to a printed circuit board and a processing method thereof. Background technique [0002] In the printed circuit board (Printed Circuit Board, PCB) field, when using the additive process (graphic plating process) to make graphic circuits, usually a single-sided tin layer 2 is formed on the upper surface of the circuit 1 (such as figure 1 shown), so that the circuit is protected by a single-sided tin layer 2. [0003] However, during the subsequent etching process, the circuit 1 is only protected by a single-sided tin layer 2 on the upper surface, but cannot be protected on both sides, resulting in side etching, which in turn leads to a decrease in line width, etch factor and impedance. On the one hand, it is difficult to obtain higher quality, which seriously affects the accuracy of signal conduction and transmission, especially on high-density PCB boards, this defect is parti...

AI Technical Summary

Problems solved by technology

[0003] However, during the subsequent etching process, the circuit 1 is only protected by a single-sided tin layer 2 on the upper surface, but cannot be protected on both sides, resulting in side etching, which in turn leads to a decrease in line width, etch factor and impedance. It is difficult to obtain higher quality, which seriously affects the accuracy of signal conduction and transmission, especially on high-density PCB boards, this defect is particularly prominent

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