Characterization of the alignment system on a laboratory extreme ltraviolet lithography tool

ABSTRACT A laboratory extreme ultraviolet lithography tool (EUVL) has been assembled atSandia National Laboratories [1]. Its major components include a Schwarzschildcamera with 0.1 jim resolution integrated with a laser plasma source (LPS) and amagnetically levitated stage. Other subsystems are a grazing-incidence optical system to maintain focus, and a through-the-lens Moire alignment system for overlay. This exposure tool is being used to study integration issues for EUVL.Experiments have been performed to characterize the alignment system's performance. The measured sensitivity of the alignment system is 15 nm 3. 1. INTRODUCTION A laboratory extreme ultraviolet lithography tool (EUVL) has been assembled atSandia National Laboratories' . Its major components include a Schwarzschild camera with 0.1 jim resolution integrated with a laser plasma source (LPS) and a magnetically levitated stage. Other subsystems include a grazing-incidence opticalsystem to maintain focus and an alignment system for overlay. This exposure toolis being used to study integration issues for EUVL. In order to demonstrate thesuccessful integration of the system, microelectronic devices and circuits will befabricated with at least one lithography step performed with EUVL.In this paper, we will describe in detail the EUVL tool and its capabilities. We willalso report results from recent experiments performed to characterize theperformance of the visible through-the-lens (TTL) Moire alignment system.