A new excimer laser micromachining method for axially symmetric 3D microstructures with continuous surface profiles

This paper presents a new method for fabricating axially symmetric 3D microstructures based on a KrF 248 nm excimer laser micromachining system. A novel mask contour scanning method is developed for obtaining a pre-described continuous surface profile with high accuracy and fast machining speed. Both convex and concave surfaces can be obtained. Four different microstructures with spherical and parabolic surface profiles with dimension around 500 μm were experimentally tested on polycarbonate (PC) samples. The surface profiles were measured and compared with theoretical counterparts. Excellent agreements both in profile shapes and dimensions were achieved. The surface roughness of the machined surfaces was also measured and the average roughness (Ra) is less than 10 nm. The machining profile accuracy and surface smoothness of this proposed micromachining method demonstrate great potentials in fabricating micro-optic components such as aspheric microlenses or microlens arrays.