Abstract: A through-the-wafer (TTW) electrically conductive connection can be produced in a heavily doped substrate. An annular trench is created from one side of the wafer such that the trench almost reaches the second side of the wafer. The annular trench can be filled with an electrically insulating material. Alternatively, an electrically insulating layer can be produced on the sides of the trench which is then filled with any material. After filling the trench, the bottom of the substrate is ground to expose the trench bottom and the front side is polished to expose the trench top. The plug of substrate material inside the annular trench is a TTW electrical connection.

Abstract: A potassium hydroxide (KOH) etch process can produce deep high aspect ratio trenches in (110) oriented silicon substrates. The trenches, however, are perpendicular to the (111) direction of the silicon substrate's crystal lattice. The trenches are used to produce thermally isolating areas and through the wafer electrical connections. These structures can be produced in a cost effective manner because of the nearly ideal capabilities of the KOH etch process when it is applied to appropriate materials at appropriate orientations.