Open cavity processing method for protecting PCB inner line by wet film

Abstract

The invention relates to an open cavity processing method for protecting a PCB inner line by a wet film. The method comprises the following steps: step 1, manufacturing an inner line on the inner layer; step 2, covering the outer surface of the inner line with a wet film layer; step 3, forming a metal film layer on the outer side of the wet film layer; step 4, coating a copper layer on the outer side of the metal film layer; step 5, pressing an outer layer on the outer side of the copper layer and arranging an outer copper layer on the outer surface of the outer layer; step 6, performing laserslotting on the outer surface of the copper layer of the protective layer to enable the copper layer on the protective layer to be exposed; step 7, adopting the etching process to perform etching treatment on the outer copper layer to form an outer line and simultaneously etching off the copper layer at the bottom of the slot; and step 8,removing the wet film layer at the bottom of the slot. Theopen cavity processing method can ensure the cleanliness inside the cavity body and avoid the problems of waste residue in the cavity body, short circuit caused by gold stain, glue flow, false fillingand interlayer holes. The method has high practicability and high popularization significance.

Description

technical field [0001] The invention relates to a circuit board processing method, in particular to a cavity opening processing method using a wet film to protect the PCB inner layer circuit. Background technique: [0002] Some current PCBs are provided with inner-layer circuits, and cavities / blind slots are provided on the PCB outside the inner-layer circuits. However, after the traditional PCB is opened, there are problems such as low cleanliness in the cavity, glue traces or resin or other waste residues in the cavity, and it is not easy to fall off. And the cavity / blind groove is usually carried out after the final surface treatment of the PCB; and in the ENIG (Electroless Nickel Immersion Gold, electroless nickel immersion gold) process or ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold, electroless nickel plating palladium immersion gold) process Finally, the gap between the lines in the cavity is easy to be stained with gold and cause a short circuit....

AI Technical Summary

Problems solved by technology

[0003] For this reason, the main purpose of the present invention is to provide a method of opening cavity using nickel or tin to protect PCB inner layer circuit, so as to solve the problem of traditional circuit board cavity opening with gold-stained inner layer circuit short circuit, waste residues that are not easy to fall off, glue flow, and false filling. , interlayer voids and poor reliability

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