Cleaning process for arranging closed glue-free space in multilayer circuit board

Abstract

The invention discloses a cleaning process for arranging a closed glue-free space in a multilayer circuit board. The process comprises the following steps of: S1, during the production and design of the multilayer circuit board, connecting internal closed areas in a conduction manner and extending the internal closed areas to a waste area; S2, carrying out drilling conduction at the fixed positionof the waste area; S3, carrying out plasma cleaning, wherein due to the fact that the internal closed area of the multilayer circuit board is communicated with the outside through drilling, the internal and external pressure difference of the closed area is eliminated, and the bubbling and bursting of the product are avoided when the product is subjected to plasma cleaning; and S4, after the plasma cleaning is finished, sealing the air holes again by using a high-temperature-resistant and aging-resistant adhesive tape so that the subsequent production process can be normally carried out. According to the invention, the air hole design in circuit board production is adopted and plasma cleaning is combined, so that the hole wall of a through hole or a blind hole is effectively cleaned, thereliability of the copper plating process is improved, and the product scrap caused by temperature and internal and external pressure difference is effectively avoided.

Description

technical field [0001] The invention relates to the technical field of circuit board preparation, in particular to a process for cleaning a closed glue-free space inside a multilayer circuit board. Background technique [0002] Multi-layer flexible boards and soft-hard boards are designed with a closed glue-free space inside, and are usually cleaned by cleaning the smear line. The cleaning of the desmearing line uses strong alkali to bite the hole wall, but this process is very easy to bite too much. There are various substances such as glue and PI in the multi-layer flexible board and flex-hard board. The cleaning target is glue, but strong alkali cannot Treated differently, resulting in excessive erosion of PI at the same time. [0003] Plasma can also be used to clean the walls of through-holes or blind holes. Since the effect of plasma cleaning on glue and PI is very different, it can improve the reliability of the copper plating process. However, plasma cleaning requir...

AI Technical Summary

Problems solved by technology

The cleaning of the desmearing line uses strong alkali to bite the hole wall, but this process is very easy to bite too much. There are various substances such as glue and PI in the multi-layer flexible board and flex-hard board. The cleaning target is glue, but strong alkali cannot Treated differently, resulting in simultaneous bites of PI causing excessive

[0003] Plasma can also be used to clean the walls of through-holes or blind holes. Since the effect of plasma cleaning on glue and PI is very different, it can improve the reliability of the copper plating process. However, plasma cleaning requires vacuuming and adding other gases, and the temperature must be raised to 60°C left and right, causing the closed area to bulge or even burst under the influence of temperature and internal and external pressure differences, causing the product to be scrapped