Fabrication of Through-Wafer Via Conductors in Si by Laser Photochemical Processing

A procedure for the fabrication of high-aspect-ratio through-wafer via conductors in Si is described. The technique is based on a rapid highly anistropic laser etching process followed by a two-step metallization. The surface area occupied by the via on the front, circuit side of the wafer, can be as small as 5 µm x 5 µm.