Solutions To Critical Problems In Soft X-ray Projection Lithography

Abstract

Present soft x-ray projection lithography systems rely on laser produced plasmas for the production of x-rays and on multilayer coated reflective masks. Target debris from the laser produced plasma can coat condenser optics and reduce system performance. The difficulty in target debris mitigation results from the large range of velocities and masses ejected from the laser produced plasma. Proposed solutions have included the use of electrostatic deflectors, a partial pressure of helium and mechanical shutters. We have completed designs on a target debris mitigation system which should efficiently transmit soft x-rays (λ ~ 13 nm) and prevent the ejected particles from reaching the condenser optics.