title: Cavity ring-down spectroscopy sensor for ion beam etch monitoring and end-point detection of multilayer structures.
abstract: This contribution reports on the development of in situ sputter monitoring and end-point detection for ion beam etch systems using continuous-wave cavity ring-down spectroscopy (cw-CRDS). The demonstrated system is based on the detection of sputtered manganese atoms using a tunable external cavity diode laser in the vicinity of 403.07 nm. The cw-CRDS system is described and measurements from a manganese-iron target are presented. End-point detection is demonstrated by monitoring the time dependence of manganese concentration for a multilayer target comprised of alternating layers of manganese/iron and titanium. Detection limits are shown to be adequate for today's commercial ion beam sputter systems.
authors.affiliation: Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, USA.
authors.forename: L
authors.initials: L
authors.lastname: Tao
authors.forename: A P
authors.initials: AP
authors.lastname: Yalin
authors.forename: N
authors.initials: N
authors.lastname: Yamamoto