Evaluation of direct patternable inorganic spin-on hard mask materials using electron beam lithography

Abstract

Two inorganic non-chemically amplified resists (XE15CB and XE15IB) were investigated. The resists are based on hafnium oxide sulfate and spin-cast from aqueous solution. They differ in sensitivity and resolution. In contrast to other studies, the materials were coated for the first time on 300 mm wafers and exposed on a 50 kV VISTEC SB3050DW variable shaped electron beam direct writer in a near-production environment at Fraunhofer CNT. In this paper, the evaluation of this resist family and its feasibility for production will be discussed. The resists were evaluated in terms of contrast, sensitivity and resolution. The process characteristics required for CMOS manufacturing such as delay stability were also examined. Furthermore, by exposing a large SRAM pattern (design CD of 22 nm), the exposure of a real application pattern was demonstrated.