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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.

The demand for smaller critical dimensions in advanced computer chips has driven projection lithography to shorter wavelengths. Deep ultraviolet systems, operating at 248 nm, are commercially available and 193 nm lithography is under development. This paper describes a research and development program to extend this trend to extreme ultraviolet (EUV) wavelengths, in the range of 11 nm to 14 nm. Research and development activities are concentrated in four major areas: (1) aspheric reflectors required in an advanced EUV camera, (2) surface- imaging resists having the required resolution and sensitivity, (3) defect-free reflecting substrates required for mask fabrication, and (4) a compact source of EUV radiation. Each of these issues is discussed and efforts to address them are described. An intermediate EUVL laboratory tool, currently under construction, will also be described. This system uses a 10x reduction Schwarzschild camera and a magnetically levitated wafer stage driven by a digital feedback controller. This system represents the first attempt at integrating all major subsystems into an EUVL laboratory tool, suitable for use in device fabrication experiments.

The development of a laboratory EUV lithography tool based on a laser plasma source, a 10x Schwarzschild camera, and a magnetically levitated wafer stage is presented. Interferometric measurements of the camera aberrations are incorporated into physical-optics simulations to estimate the EUV imaging performance of the camera. Experimental results demonstrate the successful matching of five multilayer reflecting surfaces, coated to specification for a wide range of figure and incidence angle requirements. High-resolution, 10x-reduction images of a reflection mask are shown.