Patent ID: 9184281
Filing Date: 2015-11-10
Classification: H01L

Abstract:
1. A method for producing a vertical semiconductor device, the method comprising: providing a semiconductor wafer comprising a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type forming a first pn-junction with the first semiconductor layer, and a third semiconductor layer of the first conductivity type forming a second pn-junction with the second semiconductor layer and extending to a main surface of the semiconductor wafer; forming a hard mask on the main surface, the hard mask comprising hard mask portions which are spaced apart from each other by first openings; using the hard mask to etch deep trenches from the main surface into the first semiconductor layer so that semiconductor mesas covered at the main surface by respective ones of the hard mask portions are formed between adjacent ones of the deep trenches; filling the deep trenches and the first openings of the hard mask; and etching the hard mask to form second openings in the hard mask at the main surface of the semiconductor mesas.