Patent ID: 7213327
Filing Date: 2007-05-08
Classification: H01C,H05K,Y10T

Abstract:
1. A method for fabricating embedded thin film resistors of a printed circuit board comprising the steps of: (a) forming conductive wires according to layout requirement of circuitry on a substrate made of an insulating polymer by a method selected from the group consisting of subtractive, additive, and semi-additive; (b) coating an activated layer on each of said resistor wells respectively so as to activate said substrate's insulating polymer exposed by said resistor wells; (c) immersing said printed circuit board in a electroless nickel solution so that a resistor layer having a first volume resistivity is plated on said activated layer until said resistor layer is deposited to a first thickness; (d) coating an etching resist on said resistor layer based on locations and dimensions of resistors required by said printed circuit board; and (e) etching said resistor layer to form a plurality of resistor elements matching said locations and dimensions of said etching resist, wherein each of said resistor elements has two contact points connecting with said conductive wires.