Abstract: Techniques for improved extreme ultraviolet (EUV) patterning using assist features, related transistor structures, integrated circuits, and systems, are disclosed. A number of semiconductor fins and assist features are patterned into a semiconductor substrate using EUV. The assist features increase coverage of absorber material in the EUV mask, thereby reducing bright field defects in the EUV patterning. The semiconductor fins and assist features are buried in fill material and a mask is patterned that exposes the assist features and covers the semiconductor fins. The exposed assist features are partially removed and the protected active fins are ultimately used in transistor devices.