Chemically Assisted Focused ION Beam Micromachining: Overview, Recent Developments and Current Needs

Abstract

Recent developments in FIB have included optics and automation improvements as well as technique development. in the past decade, ion beam optics have improved rapidly to the point where the beam size and profile does not dramatically limit its use in many applications ranging from failure analysis to manufacturing. Developments in FIB can therefore focus on techniques to increase removal rates, enhance selectivity and improve surface finish. in this work we present various efforts to improve FIB micromachining using chemical enhancement, where the incident ions initiate chemical reactions with surface adsorbates; and using geometrical optimization of milling patterns. Chemical enhanced FIB micromachining (CE-FIBM) techniques include the use of water vapor to improve FIB micromachining of various materials including polymers, integrated circuits and diamond as well as the use of various halogen based (F, Cl and I) precursors for machining of materials ranging from Si to Fe-Ni alloys. The machining of a free edge provides a geometrical yield enhancement of more than 5 and, when combined with simultaneous chemical enhancement, can increase total yield by as much as 30 times. The major applications of FIB for preparing cross sectional analysis samples for FIB or SEM imaging, or for TEM analysis benefit in may ways from the specialized gas chemistry assistance methods developed over the past 10 years. Integrated circuit and MEMS device editing techniques have also been enhanced through the use of unique materials specific gas assisted FIB solutions.