Patent ID: 6684497
Filing Date: 2004-02-03
Classification: H05K,Y10T

Abstract:
A method of forming a printed circuit board comprising a plurality of conductive bumps with substantially coplanar upper surfaces, said method comprising the steps of:(a) applying a continuous homogenous metal layer having a substantially planar face onto a first opposing surface of a dielectric substrate; (b) applying a first photoresist onto said face; (c) exposing and developing said first photoresist to define a pattern of conductive bumps; (d) etching the metal layer exposed by development of said first photoresist to reduce the height of said exposed metal layer and to form said plurality of conductive bumps with a continuous homogenous structure; (e) removing said first photoresist; (f) applying a second photoresist onto the metal layer; (g) exposing and developing said second photoresist to define a pattern of conductive bumps and circuit lines, wherein at least one of the circuit lines is continuous with at least one of the conductive bumps; (h) etching the metal layer exposed by the development of said second photoresist to form a pattern of circuit lines in said metal layer, wherein at least one of the circuit lines is continuous with at least one of the conductive bumps; and (i) removing said second photoresist to provide a printed circuit board comprising a plurality of conductive bumps having substantially coplanar upper surfaces.