Methods of forming a 3D structure in a substrate are disclosed. A layer of resist is deposited on the substrate. The layer of resist is patterned to define an edge at a predetermined location. The resist is reflowed to form a tapered region extending from the etch. Both the reflowed resist and the substrate are concurrently etched to transfer the tapered profile of the reflowed resist into the underlying substrate to form an angled surface. The etching is discontinued before all of the resist is consumed by the etching.
