Analysis of micro-profile in excimer laser dragging using rectangular mask

Abstract

The excimer laser machining has been widely applied to micromachining of various materials. An excimer laser dragging process to ablate a groove pattern on a polycarbonate (PC) sheet through a mask opening is analyzed in this paper. Currently, a large number of papers studying the interaction between the laser machining parameters and various materials are presented. However, the prediction of the cross-sectional profile after the laser dragging is rarely reported for the fabrication of micro-components. This work predicts the profile made by the excimer laser dragging process with a rectangular mask. To accurately predict the machined profile during the dragging process, a mathematical model describing the relationship between laser machining parameters and the produced profile is presented in this work. The proposed model shows the machined profile is determined by the machining parameters. To fabricate a complex micro-component, a method with multi-path scanning in different directions is proposed based on the modeling of the machined profile in single laser dragging. The laser machining parameters include the dragging velocity, pulse repetition rate, pulse number, fluence and the opening dimension of the mask pattern. The material PC is used in this study because of its good absorption coefficient for ultraviolet light and the excellent optical properties at the wavelength of 193 nm. The rectangular shape of mask is used during the laser dragging process. The results show the profile can be effectively predicted in laser dragging.