Patent ID: 7256071

Claim:
A method for underfilling a chip; providing a substrate; forming a solder mask over the substrate; forming a metal trace structure within the solder mask; the metal trace structure including a channel therein for the receipt of underfill; the metal trace structure further including a central portion with arms radiating outwardly therefrom, dividing the solder mask into separate areas; the substrate, solder mask and metal trace structure comprising a substrate structure; providing a chip having a series of solder bumps formed on the underside of the chip; the solder bumps being arranged in a pattern including openings; placing the underside of the chip onto the substrate structure wherein the openings in the solder bump design overlie the substrate structure's metal trace structure; and introducing underfill into the metal trace structure so that the underfill flows from the metal trace structure between the solder bumps in the solder bump design to underfill the chip.