Patent ID: 7156361

Claim:
A mold apparatus forming at least one metal bump from solder paste for direct placement on bond pads on a secondary substrate for transferring the solder paste to a contact pad of a substrate for heating during reflow into a solder ball, comprising: a substrate having a substantially flat, planar surface; at least one cavity formed in the substantially flat, planar surface of the substrate, the at least one cavity having substantially same dimensions as the at least one metal bump, the at least one cavity having a shape of one of a trapezoidal shape, a hemispherical shape, rectangular shape, and a square shape forming a first shape of the solder paste substantially conforming to the shape of the at least one cavity transferring the solder paste when slightly heated to the secondary substrate substantially in the shape of the at least one cavity and a second shape when reheated during the reflow thereof substantially drawing into a spherical shape held together by surface tension of solder material forming an approximately spherically shaped solder ball on a bond pad of the bond pads of the secondary substrate; a release layer applied to the at least one cavity minimizing the wetting of the solder paste on the at least one cavity formed in the substantially flat, planar surface of the substrate during heating thereof from the heating of the substrate; and at least one heating strip located on another surface of the substrate.