Method of fabricating a flexible circuit board

A method of forming a flexible circuit board, comprising the steps of:

• (a) providing a substrate, wherein the substrate comprises a first surface and a second surface opposite to the first surface and the first surface is for forming conductive traces;
• (b) sputtering a copper film on the first surface of the substrate;
• (c) forming a photo-resistor layer over the copper film, wherein a pattern of the photo-resistor layer is complementary to the conductive traces and a portion of the copper film is exposed;
• (d) plating a copper layer over the exposed portion of the copper film as the conductive traces;
• (e) removing the photo-resistor layer;
• and
• (f) burning the insulation tape to form a plurality of contact holes which expose the conductive traces, using laser-ablation.

A method of forming a flexible circuit board, comprising the steps of:

• (a) providing a substrate, wherein the substrate comprises a first surface and a second surface opposite to the first surface and the first surface is for forming conductive traces;
• (b) forming an adhesive layer on the first surface of the substrate;
• (c) burning the insulation tape to form a plurality of contact holes, using laser-ablation;
• (d) adhering a copper layer on the adhesive layer;
• and
• (e) defining the copper layer to form the conductive traces by photolithography.