Wafer through-hole interconnections with high vertical wiring densities

A novel wafer through-hole technique with a high vertical wiring density is introduced compatible with standard semiconductor processes. The basic idea is to realize metallic interconnection lines on the inclined sidewalls of anisotropically etched through-holes in (100) oriented silicon substrates. The key process is the application of an electrodeposited photoresist capable of covering such complex three-dimensional structures. Further, conventional deep ultraviolet light exposure enables photolithography on the inclined sidewalls with a good resolution, Interconnections have been achieved with line widths of 20 μm enabling wiring densities up to 250 cm^-1