Patent ID: 7795134

Claim:
A method for processing a substrate, comprising: forming a via in a substrate having a first surface and a second surface opposite the first surface, the substrate including a bond site at least proximate to the first surface, the via having an opening proximate to the bond site of the substrate, the opening having a width, a bottom portion in the substrate, and a sidewall with a length generally transverse to the width, the length being approximately 100 microns or more; contacting the sidewall of the via with a precursor of a conductive material in a supercritical fluid; precipitating the conductive material from the precursor in the supercritical fluid onto the sidewall of the via; maintaining a generally uniform concentration of the precursor in the supercritical fluid throughout the via as the conductive material is precipitated from the precursor; forming a conformal layer of the conductive material on the sidewall of the via from the precipitated conductive material while the via is exposed to the supercritical fluid, the layer of the conductive material having a generally uniform thickness over substantially the entire length of the via in a direction transverse to the width of the via; after forming the conformal layer, forming a vent hole in the substrate extending from the bottom portion of the via to the second surface of the substrate; filling the via with a fill material adjacent to the conformal layer of the conductive material after forming the vent hole, the fill material having a first end proximate to the first surface; exposing a second end of the fill material opposite the first end by removing material from the second surface of the substrate; and attaching a solder ball to the exposed second end of the fill material, the solder ball being in electrical communication with the bond site of the substrate via the fill material in the via.