Patent ID: 8823168

Claim:
An electrical device comprising: a substrate having a first face comprising a plurality of wells or recesses, wherein each well or recess contains at least one contact pad; a die having a first face; a plurality of copper pillers CuP's extending from said first face of said die, each CuP having a distal end and a solder tip mounted on said CuP distal end, each said solder tip having a distal end; a first c-stage resin layer having a relatively larger amount of filler particles therein, said first c-stage resin layer having a first surface adhered to said first face of said die and having a second surface opposite said first surface thereof; and a second c-stage resin layer having a relatively smaller amount, if any, of filler particles therein, said second c-stage resin layer having a first surface adhered to said substrate first face and having a second surface opposite said first surface that is adhered to said second surface of said first c-stage resin layer; wherein, said plurality of contact pads are comprised of: an inner copper member; a metal cap covering the inner copper member, composed of a material selected from the group of nickel, gold, solder or various alloys thereof; wherein the tops of each of the plurality of the contact pads are be positioned in the well or recess having a base at a distance of about 10 um below a top surface of the substrate.