Advantageous Exposure of X Architecture Patterns when Using a Variable-Shaped Beam Tool

Abstract

The concept of introducing diagonal interconnects in chip manufacturing offers several advantages and is known as X architecture. We investigated the fabrication of such patterns for high-resolution direct writing applications using variable-shaped electron beam lithography. The variable-shaped beam offers throughput advantages for Manhattan patterns. These advantages apply also to X architecture patterns, provided slanted rectangular and triangular shots can be used for pattern generation. This specific shot generation method has already been incorporated in Leica SB350 electron beam writing tools, so that it has become possible to significantly reduce the number of shots required for exposing X architecture layouts. The resolution is not affected by the pattern orientation. 130 nm pitch lines and spaces with axis-parallel and slanted orientations were successfully exposed in a 250-nm-thick NEB-33 resist.