Abstract
Multi layer Flexible Printed Circuit(FPC) with the flexible and the ultra thin structure (0.2mm for 4 layers) has been achieved with material technology, circuit patterning (L/S=50/50um), designing and multiple lamination. The Electrical connection between layers is achieved by creating thru holes or blind via holes. Therefore it is possible to have a multi-layer structure without having a thru hole that passes through all layers. Laser drilling technology is applied for via holes. The new adhesive material has been developed as of the insulation layer. This multi layer FPC can be handled in roll to roll through whole fabrication process by controlling the fluidity of the adhesive above.
