Soft-hard printed circuit board combination process

Abstract

The invention discloses soft-hard printed circuit board combination process, including that bonding sheets are firstly packaged between inlayer flexible printed circuit boards, the inlayer flexible printed circuit boards are subject to lamination and curing, and then outer flexible printed circuit board is packaged, thus completing forming of soft-hard printed circuit board. PI copper foil used by flexible printed circuit board is more than FR4 copper foil used by hard printed circuit board, thus the hole depth of outer blind hole can be well controlled, the blind hole depth can be controlled to be 40 Mum if 12 Mum no-glue PI copper foil is used, thus greatly improving blind hole copper depositing and plating yield. Thus, the invention can conveniently control the outer blind hole depth while ensuring rigidity and thickness of four-layer HDI soft-hard printed circuit board and improve blind hole copper depositing and plating quality, PI copper foil and PP bonding sheet are adopted, structure is simple and the soft-hard printed circuit board is easy to make, cost is low, and electric performance of product is improved.

Description

technical field [0001] The invention relates to a circuit board processing method, in particular to a combination process of soft and hard circuit boards. Background technique [0002] With the development of electronic technology, especially the continuous improvement of electronic assembly technology, in many cases, it is difficult for ordinary rigid circuit boards to meet the requirements of "light, thin, short and small" electronic products. The flexible circuit board, with its "light and thin" and "bendable" characteristics, can just meet this trend, especially the rigid-flex circuit board (a circuit board combined with a flexible base material and a rigid base material) has the advantages of a rigid circuit board. It has a supporting function and the characteristics of a flexible circuit board, so its application has more and more extensive prospects due to its remarkable advantages, and it can be used in almost all kinds of electronic equipment. At present, the struc...

AI Technical Summary

Problems solved by technology

[0023] 1. The flexible board area of ​​the soft-rigid board needs to be protected, but during the production, especially after the DES line, copper plating and other wet processes, the liquid medicine will penetrate into the inner flex board, causing abnormalities in the inner layer

[0024] 2. The base material of the rigid board, FR4 copper-clad laminate, is double-sided copper foil. To make the outer hard board of the soft-rigid board, only one side of copper is needed, and one side of the copper needs to be etched away, which wastes one side of copper and increases the process. high cost

[0025] 3. FR4 copper-clad laminates are hard materials, usually relatively thick. At present, the minimum thickness of FR4 copper-clad laminates is 0.14mm. If the outer layer blind holes are made on this structure, the depth of the blind holes is more than 150um, and the blind holes are semi-closed state, the liquid exchange rate is low, if the blind hole is too deep, for a blind hole of 0.1mm or smaller, it will cause the blind hole to be difficult to copper or the copper in the hole is very thin, which cannot meet the performance requirements

[0026] 4. After punching, the window protection layer needs to be removed, increasing the process

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