FEEDTHROUGH STRUCTURE FOR THREE DIMENSIONAL MICROELECTRONIC DEVICES

摘要

A method and structure for reducing the surface area occupied by feedthrough in a semiconductor substrate. A buried horizontal conducting path (30) is laid down on a major surface (12) of a substrate (10), with one end (32) of the conducting path (30) in electrical and physical contact with the feedthrough (20) (e.g. a thermal gradient zone melt TGZM). An epitaxial layer (40) is put down over the TGZM and over the buried horizontal conducting path (30). Electrical contact is made to the distal end (31) of the buried horizontal conducting path (30) by diffusion through the newly put down epitaxial layer (40) or by etching to the conducting path. The diffused region (50) is of the same dopant characteristics and conductivity type as are the horizontal path (30) and TGZM. The cross-sectional area of the diffusion region (50) is 25 to 30 square microns compared to the 507 to 2027 square microns area of the TGZM. This results in substantial reduction of the surface area occupied by feedthrough structures and allows more devices to be fabricated on the surface of the substrate.