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.