According to an embodiment, a method of forming a semiconductor device includes: providing a wafer having a semiconductor substrate with a first side a second side opposite the first side, and a dielectric region arranged on the first side; mounting the wafer with the first side on a carrier system; etching a deep vertical trench from the second side through the semiconductor substrate to the dielectric region, thereby insulating a mesa region from the remaining semiconductor substrate; and filling the deep vertical trench with a dielectric material.