ACHROMATIC MICROBEAMS FOR INTEGRATED CIRCUIT FABRICATION

CHROMATIC ABERRATION LIMITS THE CURRENT DENSITY WHICH CAN BE PRODUCED BY FOCUSED ION BEAM SYSTEMS UTILIZING ELECTROSTATIC LENSES. STUDY OF SYSTEMS COMPRISING A LIQUID METAL FIELD IONIZATION SOURCE AND AN ACHROMATIC QUADRUPOLE LENS DOUBLET OFFERS THE PROSPECT OF OVERCOMING THIS LIMITATION. RESEARCH OBJECTIVES IN PHASE I INCLUDE IMPLEMENTATION OF METHODS TO COMPENSATE DEFECTS OTHER THAN CHROMATIC ABERRATION, AND THE EXPERIMENTAL DEMONSTRATION OF AN ACHROMATICALLY FOCUSED BEAM WITH A DIAMETER MEASURED IN NANOMETERS. RESEARCH OBJECTIVES OF PHASE II INCLUDE DESIGN AND CONSTRUCTION OF ACHROMATIC LENSES OPTIMIZED FOR SEMICONDUCTOR APPLICATIONS, AND THEIR USE IN AN EXPERIMENTAL SYSTEM WITH A PROBE SIZE OF ABOUT 10 NANOMETERS AND WITH CURRENT DENSITY. DECREASED FEATURE SIZE IS AN IMPORTANT GOAL IN THE FABRICATION OF INTEGRATED CIRCUITS. IN ADDITION, ION BEAM CURRENT DENSITIES HIGHER THAN PRESENTLY OBTAINABLE ARE REQUIRED FOR MASK FREE, DIRECT-WRITE DOPING AND ESPECIALLY FOR LITHOGRAPHY OF VERY SMALL CIRCUIT FEATURES. ACCORDINGLY, THE POTENTIAL APPLICATION OF THE RESEARCH IS TO FABRICATION OF HIGHLY COMPLEX INTEGRATED CIRCUITS.