Glue filling process for thick copper rigid-flex board

Abstract

A glue filling process for a thick copper rigid-flex board comprises the following steps: (1) electroplating a flexible board which comprises a PI layer and a first copper layer laminated on the PI layer; (2) arranging a flexible circuit board; (3) pasting a covering film on the flexible board, namely pasting the covering film on the flexible board at a position corresponding to the flexible area; (4) pasting a PI protective film: pasting the PI protective film on a position, corresponding to the flexible area, on the flexible board; (5) laminating, namely laminating high flow glue PP and the second copper layer on the first copper layer in the flexible area in sequence; (6) implementing hard board electroplating and hard board circuit; (7) carrying out UV laser cutting, and cutting off the high-flow glue PP flowing into the flexible area; and (8) uncovering, and removing the PI protective film and the high flow glue PP flowing into the flexible area; According to the invention, the problem of board explosion or bubbling caused by insufficient glue filling and bubbles between lines is avoided. The PI protective film is used for protecting the flexible area, so that the problem of'glue overflow 'is avoided.

Description

technical field [0001] The invention relates to a circuit board manufacturing process, in particular to a glue filling process for a thick copper-flexible-rigid bonded board. Background technique [0002] The lamination process of the printed circuit board is to fill the gap between the lines through the glue in the PP between the layers to play the role of adhesion and insulation. For traditional rigid-flex boards, because the current passing through the traces is relatively small, the copper thickness of the traces is relatively thin (about 20 μm), so most of them use low-flow glue PP (LOW Flow PP). However, as the functions of mobile communication terminals continue to increase, and long-term use leads to the need for heat dissipation, especially the battery protection soft-hard combination board used in the battery area, the required copper thickness is thicker (45μm or more); if PP with low flow glue is used , there is insufficient glue flow, and the following problems...

AI Technical Summary

Problems solved by technology

[0003] 1. Insufficient glue filling, there are "voids and bubbles" between the lines. During reflow soldering and patch welding, thermal expansion and contraction under high temperature conditions are prone to "burst / bubble" phenomenon

[0004] 2. The glue in PP flows between the copper wires, resulting in insufficient glue between the glass fiber in PP and the copper wires, poor bonding force, and easy to peel off

[0005] If PP with high-flow glue is used, during pressing, the heat in PP becomes a fluid state, and a large amount of glue overflows from the joint between the hard board and the soft board, and flows to the area of ​​the soft board, forming a soft-hard joint line of the soft-hard board. Irregular glue flow in the area, that is, the problem of "overflow glue" ( Figure II ), damage the cover film on the soft board, affect the electrical performance, bending and assembly

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