Multi-layer flexible circuit board and fabrication method thereof

Abstract

A multi-layer flexible circuit board comprises a plurality of conductive circuit layers and a plurality of insulation layers, wherein the insulation layer is arranged between adjacent conductive circuit layers, a plurality of first-order blind holes and a plurality of second-order blind holes are formed in the multi-layer flexible circuit board, the first-order blind holes are filled with first-order conductive posts, the second-order blind holes are filled with second-order conductive posts, the first-order conductive posts and the second-order conductive posts are matched to make the plurality of conductive circuit layers electrically connected, the plurality of conductive circuit layers comprise a first external conductive circuit layer, a second external conductive circuit layer and a plurality of internal conductive circuit layers, the plurality of second-order blind holes comprise a first second-order blind hole, the first second-order blind hole is filled with a first second-order conductive post, the plurality of internal conductive circuit layers comprise a first internal conductive circuit layer, a second internal conductive circuit layer and a third internal conductive circuit layer which are adjacent to one another, and the first internal conductive circuit layer, the second internal conductive circuit layer and the third internal conductive circuit layer are electrically connected by the first second-order conductive post. Moreover, the invention also provides a fabrication method of the multi-layer flexible circuit board.

Description

Technical field [0001] The invention relates to a multilayer flexible circuit board and a manufacturing method thereof. Background technique [0002] Flexible Printed Circuit Board (FPC) is used in notebook computers, LCD monitors, digital cameras, mobile phones, digital cameras, smart watches, etc. due to its advantages such as bendability, light weight, small footprint, and three-dimensional wiring. Consumer electronic products have a very wide range of applications. With the increasing requirements for information processing of consumer electronic products, multi-layer circuit boards have multiple circuit layers and thus have more wiring area. Therefore, flexible multi-layer circuit boards have gradually replaced flexible single-sided circuit boards and flexible double-sided circuit boards. Surface circuit boards are increasingly used in consumer electronic products. Multi-layer flexible circuit boards in wearable products are increasingly developing towards multilayer arbit...

AI Technical Summary

Problems solved by technology

[0003] The existing multi-layer flexible circuit boards mostly use the method of gradually adding layers and forming holes in a single layer to form plated holes to electrically connect two adjacent conductive layers. However, this method is not only difficult to align between layers, but also The production process is longer and the production time is longer

The existing multi-layer flexible circuit board also has a through hole penetrating through the upper and lower sides of the insulating substrate directly on the substrate, and a columnar metal needle is riveted in the through hole, and the metal needle is electrically connected to the conductive layer above and below the insulating substrate. However, the multilayer flexible circuit board made by this method cannot realize the electrical connection between any two conductive layers.

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