Patent ID: 6434819
Filing Date: 2002-08-20
Classification: H05K,Y10T

Abstract:
A process of producing a multilayer circuit board having multiple layers of conductor wiring patterns with insulating layers having vias extending therethrough to provide electrical connection between the conductor wiring patterns, the process comprising the steps of:providing a circuit board having a conductor wiring pattern formed on one side thereof; forming an insulating layer covering the conductor wiring pattern and said one side of the circuit board; forming a viahole extending through the insulating layer to the conductor wiring pattern, the viahole having a bottom defined by an exposed portion of the conductor wiring pattern; forming a recess in the insulating layer, the recess extending from an orifice of the viahole in the same pattern as another conductor wiring pattern which will be formed on the insulating layer; forming a conductor layer covering the insulating layer and filling the viahole and the recess; and abrasive-working the conductor layer until the insulating layer is exposed so that portions of the conductor layer that fill the viahole and the recess remain unremoved and form a via and a wiring pattern that have top surfaces flush with a top surface of the insulating layer.