Demonstration of 22nm SRAM features with patternable hafnium oxide-based resist material using electron-beam lithography

Abstract

To fulfill the requirements of future technology nodes new resists with high resolution, high sensitivity and low LWR and LER respectively are needed. A new inorganic non-chemically amplified resist (XE15IB, an experimental resist provided by Inpria Corp.) was investigated. The resist is spin-cast from aqueous solution and is based on hafnium oxide. Metal oxide based resist as XE15IB supersede other resist materials due to its high etch resistance. 1, 2 This new material can be considered as a direct patternable spin on hard mask. XE15IB was processed in a 300 mm complementary metal oxide semiconductor (CMOS) manufacturing environment and exposed on a 50 kV VISTEC SB3050DW variable shaped electron beam direct writer at Fraunhofer Center Nanoelectronic Technologies (CNT). The resist was evaluated in terms of contrast, sensitivity and resolution. The process characteristics required for CMOS manufacturing such as delay stability were also examined. Furthermore, by printing a large static random access Memory (SRAM) pattern (design CD of 22 nm), the exposure of a real application pattern was demonstrated.