Numerical studies on thermophysical process in laser-assisted thermal probe fabrication of nanostructures

The temperature distribution of both the nanotip and the substrate during thermal scanning probe lithography processing is a critical factor that significantly influences the processing outcomes. The nanotip and the contact area both exhibit a relatively small spatial scale, which presents a significant challenge in accurately measuring the temperature distribution during thermal processing. In this study, finite element simulations are carried out to investigate the thermophysical process between the laser-irradiated nanotip and the PMMA substrate. The temperature distributions of the nanotip and substrate at different contact thermal resistances, apex radii, and vertical loads are investigated. The findings reveal that as the thermal contact resistance rises, the average temperature of the interface between the nanotip and the PMMA substrate diminishes, while it increases with the rise in the vertical load. The maximum average temperature reaches 669.51 K when the laser power and apex radius are 20 mW and 20 nm, respectively. Furthermore, the effective area of heat conduction, delineated by temperatures surpassing the glass transition temperature of PMMA, exhibits a similar trend to the average temperature. The results obtained under various conditions provide theoretical insights for optimizing the process settings of laser-assisted precise fabrication.