20 nm electron beam lithography and reactive ion etching for the fabrication of double gate FinFET devices

Abstract

New device concepts have been introduced to overcome the problems of planar microelectronic devices. The FinFET, which is a variant of the double gate transistor concept, is a promising approach, requiring very fine lithography and etching processes. These steps have been implemented as process modules in a loop to standard production. An electron beam lithography system has been optimized for nano-patterning down to 20 nm with emphasis on feature size, overlay accuracy and automation. A four-step pattern transfer process with hard masks has also been developed using a high density plasma tool. Structures with steep side walls could be etched. The fin structures are imaged in TEM with direct and elemental mapping. The analysis of the side wall deposited during the etching process reveals that the etching is carbon free.