DEVELOPMENT OF ION SOURCES FOR ION PROJECTION LITHOGRAPHY

Multicusp ion sources are capable of generating ion beams with low axi al energy spread as required by the ion projection lithography (IPL). Longitudinal ion energy spread has been studied in two different types of plasma discharge: the filament discharge ion source characterized by its low axial energy spread, and the rf-driven ion source character ized by its long source lifetime. For He+ ions, longitudinal ion energ y spreads of 1-2 eV were measured for a filament discharge multicusp i on source which is within the IPL source requirements. Ion beams with larger axial energy spread (similar to 7 eV) were observed in the rf-d riven source. A double-chamber ion source has been designed which comb ines the advantages of low axial energy spread of the filament dischar ge ion source with the long Lifetime of the rf-driven source. The ener gy spread of the double chamber source is approximately 2 eV. (C) 1996 American Vacuum Society.