Exploring the origin of charging-induced pattern positioning errors in mask making using e-beam lithography

摘要

The authors present a detailed observation of the charge-induced pattern positioning errors (CIPPEs) in a variable-shape e-beam writer on an opaque-MoSi-over-glass (OMOG) mask by directly measuring the pattern shifts using a mask registration tool. The CIPPEs are found to have one short-range, that is exponentially decaying in space, and the other constant offset components. The exponential term that decays slowly in time, whereas the constant offset fast diminishes. By applying a charge dissipation layer (CDL), the authors experimentally verify that the exponential component results from the charges in resist. On the other hands, the constant offset that can not be eliminated by the CDL is speculated to be charges in the substrate according to the Monte Carlo simulation.