Flexible circuit board and manufacturing method thereof

Abstract

The invention provides a manufacturing method for a flexible circuit board. The manufacturing method comprises: a substrate is provided, wherein the substrate consists of a base layer, a first bottom copper layer, and a second bottom copper layer; hole opening is carried out to obtain a first hole passing through the base layer and the first bottom copper layer; a dry film is pasted on the first bottom copper layer and the second bottom copper layer; the part of dry film is removed to expose the part of first bottom copper layer, wherein the exposed first bottom copper layer encircles the first hole in an annular mode; copper reduction processing is carried out on the exposed first bottom copper layer, so that a second hole communicated with the first hole is formed in the first bottom copper layer; local copper plating is carried out on the first hole and the second hole to form copper-plated hole rings are formed on the walls of the first hole and the second hole and a conducive hole is obtained; and the dry film is removed and the first bottom copper layer is processed to form a circuit layer, thereby obtaining a flexible circuit board. In addition, the invention also relates to a multi-layer flexible circuit board formed by using the manufacturing method.

Description

technical field [0001] The invention relates to the field of circuit board manufacturing, in particular to a flexible circuit board and a manufacturing method thereof. Background technique [0002] As the conductive lines in the flexible circuit board become more and more dense, it is not only necessary to rely on multi-layer boards to meet its layout requirements, but also puts forward detailed requirements for the conductive lines themselves. Usually, the copper plating process is selected for the production of thin lines, which can avoid limiting the etching ability due to the excessive thickness of the copper layer after full-board electroplating. However, the selected plating hole ring formed by this method is formed on the circuit layer, so there must be a break at the selected plating hole ring. In order to ensure the conduction reliability of the conductive holes, the hole ring break is generally more than 10 microns (um), and the more layers of the circuit board, t...

AI Technical Summary

Problems solved by technology

[0003] Furthermore, dry film is used in the circuit manufacturing process. The thicker the gap, the thicker the dry film, and the poorer the resolution of the dry film, which also affects the production of thin lines.

Images