Metrology of Thin Films by Focused Laser Spike Dewetting

Focused laser spike (FLaSk) dewetting utilizes thermocapillary shear forces generated by laser-induced extreme thermal gradients to move molten materials down thermal gradients. Past work, which has explored the patterning potential of this technique, demonstrated that evolution of the driven dewetting patterns formed by FLaSk is highly sensitive to not only the parameters of the laser, but also to specific parameters of the dewetted material. The most significant effects tie to the melt viscosity. This talk will discuss the use of FLaSk as a tool to probe factors that affect the viscosity of the melt, including surface modification, crystallization, and phase separation. The key advantage to this approach is that a single FLaSk “experiment,” consisting of a point-exposure with a controlled set of parameters, can occur on a sub-mm or even sub-micron region independently from other FLaSk experiments. Therefore, a mm-patch of material can contain hundreds to millions of experimental conditions. By using a calibrated heating substrate, the thermal conditions of the different exposure profiles can be well characterized. Further, optical analysis techniques can lead to high-throughput evaluation of the results.