Patent ID: 6228681
Filing Date: 2001-05-08
Classification: H01L

Abstract:
A method for providing a two-stage solder bump on a wafer surface, the method comprising the steps of:a) providing a substrate having at least one solderable contact site on a surface thereof;b) applying an underfill material to the substrate surface in a manner which substantially entirely covers the substrate surface and the solderable contact site;c) treating the underfill material to form at least one aperture therein, the at least one aperture extending substantially entirely through the underfill material and being located such that it exposes only the solderable contact site;d) applying at least one bump of a first composition to the assembly in a manner such that a bump occupies each aperture in the underfill, contacts the exposed solderable contact site therein, and extends above the underfill material;e) applying a cap to at least one bump, the cap being formed of a second composition; andf) applying a flux to the surface, the flux covering at least the exposed portions of the caps.