| 摘要 |
The present invention relates to a technique for protecting the inner layer circuit of a multi-layer flexible printed circuit board and, more specifically, to a method for protecting an inner layer circuit from an etching process about the copper foil of an outer layer in a process of forming an outer layer circuit. In order to achieve the forementioned, the present invention firstly protects the inner layer circuit by enabling the semidry protective ink for printing on the inner circuit to play an adhesive role between the inner circuit and the copper foil of the outer layer and secondly protects the inner layer circuit by making the outer layer copper foil on the inner circuit remain without removing the outer layer copper foil. [Reference numerals] (AA,II) Dry film;(BB,HH) Copper foil;(CC,GG) Adhesive;(DD,FF) Flexible ink;(EE) Inner layer FPCB |
