Preparation method of multi-layer flexible printed circuit

Abstract

The invention discloses a preparation method of a multi-layer flexible printed circuit. The preparation method of the multi-layer flexible printed circuit comprises the following steps: providing flexible base materials of a first surface and a second surface which are arranged back to back; setting a first circuit layer on the first surface; setting a first insulating medium layer on the first circuit layer; processing and forming a number of through-holes on the first insulating medium layer; coating a conductive slurry or ink on the insulating medium layer, and making a part of the conductive slurry or ink flow into the through-holes and contact with the first circuit layer; then solidifying the conductive slurry or ink to form a second conductive layer on the insulating medium layer and form a conductive filler which can at least connect the first and second circuit layers electrically in the through-holes; and repeating the above operations until more than two insulating layers and more than three circuit layers are formed. The preparation method of the multi-layer flexible printed circuit is simple and easy to implement, has the advantages of good controllability, low cost and friendly environment, and benefits large-scale implementation; and the obtained printed circuit has super thin and soft characteristics.

Description

technical field [0001] The application specifically relates to a preparation process of a multilayer flexible circuit board, which belongs to the technical field of circuit board manufacturing. Background technique [0002] With the advancement of electronic technology, electronic products are developing toward diversification, intelligence, and flexibility. The most typical representative is the rise of smart wearable electronic products, which put forward higher requirements for the circuit boards. Flexible circuit board, also known as flexible circuit board, flexible circuit board, referred to as soft board or FPC (Flexible Printed Circuit), has the characteristics of high wiring density, light weight, thin thickness, and bendability, and is especially suitable for complex shapes. , Electronic products with narrow internal space or complex human morphology. [0003] Flexible circuit boards are divided into single-sided, double-sided and multi-layer boards, and the base m...

AI Technical Summary

Problems solved by technology

[0004] When a traditional flexible circuit board is prepared as a multi-layer board, it generally starts with the inner layer pattern, and after etching, bonding and pressing, the through hole is usually realized by mechanical drilling or laser drilling, but the buried and blind holes of the circuit It is difficult to achieve through drilling, which limits the development of flexible circuit boards in the direction of high density, high precision and number of layers; in addition, the temperature of the pressing process is relatively high, making flexible circuit boards basically use polyimide high temperature resistant materials, which The material of the flexible circuit board is limited, and the thickness of the copper foil and the substrate is limited. At present, the thickness of the single-layer flexible circuit board is greater than 100 μm, and it is difficult to achieve multi-layer and ultra-thin; moreover, the traditional flexible circuit board production The process is long and the cost is high. The conductive lines are formed by taking metal copper foil and etching it with chemical water. This process will produce waste water that is difficult to purify and treat, which will cause serious and long-term pollution to the surrounding natural environment such as nearby rivers and soil.

Images