Flexible printed wiring board for chip-on-film

Abstract

There is provided a flexible printed wiring board including an insulating layer having a high optical transmittance, a high adhesion strength and a high migration resistance, and suitable for a chip on film (hereafter referred to as COF). In a flexible printed wiring board for COF, having an insulating layer on which a conductive layer of an electrodeposited copper foil is laminated, and an optical transmittance of 50% or more of the insulating layer in the etched region when a circuit is formed by etching said conductive layer, electrodeposited copper foil was made to have a rust-proofing layer of a nickel-zinc alloy on the adhering surface to be adhered to the insulating layer; the surface roughness (Rz) of the adhering surface was made to be 0.05 to 1.5 mum, and the specular gloss was made to be 250 or more when the incident angle is 60°.

Description

technical field [0001] The present invention relates to flexible printed circuit boards. In particular, it relates to flexible printed wiring boards suitable for chip-on-film types. Background technique [0002] In recent years, with the development of the electronic equipment industry, there is an urgent need for flexible printed circuit boards that can assemble electronic components such as ICs and LSIs. Furthermore, the miniaturization of the electronic equipment itself, that is, miniaturization, lightness, and high performance are rapidly progressing. For this reason, as a method of assembling these electronic components, etc., TAB (tape transfer automatic bonding) tape, T-BGA (ball grid array) tape, ASIC (application specific integrated circuit) tape, etc. for assembly of flexible film conveyor belts can be used. method. Especially for electronic devices with liquid crystal displays such as personal computers and mobile phones, due to the rapid advancement of high pr...

AI Technical Summary

Problems solved by technology

[0010] However, if the copper foil with reduced surface roughness of the adhesive surface is used, the adhesion between the conductive layer and the insulating layer will inevitably occur, that is, the peel strength (peel strength) of the conductive circuit will decrease. Various investigations of resin types or surface treatment methods including surface roughness on the copper foil adhesion surface lead to the result that it is necessary to manufacture a laminated film with the required peel strength

In addition, although the light transmittance of the laminated film can be controlled to a certain extent by controlling the surface roughness of the copper foil adhesion surface, a laminated film with a specified light transmittance and good adhesion can be realized, but how to use it according to the parameters The problem of quality management of the adhesion surface of electrolytic copper foil is not clear enough, and it is in urgent need of an early solution.

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