New Test Structure Development for Pattern Collapse Evaluations

Abstract

Test structure development is critical for single wafer pattern collapse evaluations. A good test vehicle not only allows optimization and benchmarking of different processes, but also facilitates understanding of the underlying mechanism. For high aspect ratio silicon nanopillar arrays, by increasing the gap distance in one direction while keeping the other direction constant, an unexpected higher collapse rate is found. This preliminary finding is contradictory to the prevalent models that are based on equilibrium force balance between capillary and mechanical interactions. It is postulated that the asymmetric arrangement of pillars facilitates the formation of liquid bridge and thus more pattern collapse. Such test structures can bring useful insights to understand the dynamic mechanism of pattern collapse.