Femtosecond Laser Ablating Depth for Nanometer-Sized Thin Metal Films

Femtosecond laser machining for nanometer-sized metal thin films is a key process commonly required in the manufacturing of modern electronic devices. It is generally known that thermal transport in nanometer-sized devices and in ultrashort process may deviate from the Fourier's law. This possibly leads to different ablation characteristics from conventional laser processing. This paper employs a two-temperature model with the vaporization at solid vapour interface to analyze the thermal process for femtosecond laser ablation of the metal film. The ablation depth per pulse predicted by this work agrees with the available measured data. The effects of material properties on the ablated depth are also discussed.