Cavity ring-down spectroscopy sensor for ion beam etch monitoring and end-point detection of multilayer structures.
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.
Tao
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Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, USA.
Yalin
A P
AP
Yamamoto
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N