Lithography Wand-Fabrication And Applications Of Novel Microstructures For Electron And Ion Beam Nanometer Lithography

Abstract

A novel multiple electron or ion beam methodology has been developed with the potential for gigahertz patterning data rates and patterning of nanometer features. The technique is based on the concept of a combined aperture-deflector-and-lens microstructure which is fabricated into a silicon wafer. The microstructure, designated as the lithography wand, can be used to shape and control large numbers of charged particle beams for pattern generation as it generates a linear wave of patterns as its beam array is scanned across a prepared surface. The wand consists of an array of apertures which shape an incoming broad beam into individual beams and allow simultaneous deflection of individual beams along with common focusing for the aggregate of beams. Fabrication of a wand control structure with a five pole Einzel lens has been demonstrated. The multipole lens is constructed from a stack of various conductor and insulator layers that are deposited on a micromachined silicon substrate and subsequently patterned and etched to form lens poles and deflectors. Microfabrication techniques utilizing trilayer resist are used to construct a sub-tenth micron wand aperture and a multipole wand lens, with precision dimensional control. A near-UV trilayer resist structure was used for fabrication of the lens and aperture beamline. An E-beam trilayer resist process was used in conjunction with precision etching to generate 400 nm patterns with excellent dimensional control to fabricate 80 nm square apertures with ± 10% dimensional control (2σ). In this paper, design concepts relative to a wand based multibeam lithography system are described. Fabrication of the central controller wand microstructure is described. Construction of versions of these structures with 80 nm apertures and with aperture/Einzel lens combinations are demonstrated using Shipley SAL600 negative electron beam resist. Far submicron (0.10 μm) resist patterns generated using microstructures in an electron beam column are demonstrated.