Patent ID: 8304277

Claim:
A method of making a semiconductor device, comprising: providing a base substrate having first and second opposing surfaces; forming a first etch-resistant conductive layer over the first surface of the base substrate; etching a plurality of first cavities in the base substrate through an opening in the first etch-resistant conductive layer, the first cavities having a width greater than a width of the opening in the first etch-resistant conductive layer; etching a plurality of second cavities in the base substrate between portions of the first etch-resistant conductive layer; providing a semiconductor die having a plurality of bumps formed over contact pads on an active surface of the semiconductor die; mounting the semiconductor die to the base substrate with the bumps disposed over the first etch-resistant conductive layer; reflowing the bumps to electrically connect to the first etch-resistant conductive layer and cause bump material to flow into the first cavities; depositing an encapsulant over the semiconductor die and base substrate; and removing a portion of the second surface of the base substrate down to the second cavities to form electrically isolated base leads under the first etch-resistant conductive layer.