Sub-micromachining using femtosecond pulse laser interference phenomenon

Abstract

This research work sets out to achieve submicromachining capabilities on the femtosecond pulse laser which surpasses the conventional laser micromachining method of using the direct laser beam to machine. The aim is to achieve laser ablated features of 200nm and below with this novel research concept. With ultrafast pulse lasers such as the femtosecond pulse laser, subspot size micromachining is possible because of their precise threshold value. However, the sub-spot size ablation mechanism has reached its lowest limit when it hit the 1/1 Oth of the laser focal spot size range. Up to now, the smallest laser micromachined feature reported is 200nm in diameter, or approximately 8 percent of the original laser spot size of 2.5um. The aim of this research work is to break through this limit and obtain submicron features of below 200nm with the femtosecond pulse laser.