Optimization of Nd:YAG Laser beam and Process Parameters for Quality Micromachining of Monocrystalline Silicon

Abstract

Monocrystalline silicon is an important material for the manufacture of MEMS and MOEMS devices. Formation of microcracks and extensive heat a ected zones are major challenges associated with laser micromachining. In recent times, lasers have gained popularity in micromachining applications. This trend has been due to the various unique properties that lasers possess. These properties include the ease of manipulation, and the ability to focus the beam to a small spot. In this research, e ects of the Nd:YAG laser beam and process parameters on cut quality attributes of monocrystalline silicon were investigated. The parameters investigated were: scan speed, power and beam spot diameter. The quality attributes investigated were kerf depth, and thermal stress e ects such as microcracks formation. A numerical model was developed using nite element analysis method to investigate the parameters and attributes. The results of the study show that increasing the laser scan speed led to a decrease in the kerf depth and a decrease in microcracks formation. Also, increasing the spot diameter of the beam led to a decrease in kerf depth and a decrease in the microcracks formation. Increasing the laser power led to an increase in kerf depth, and an increase in microcracks formation. The simulation results were validated by comparison to experimental ones. The models satisfactorily predicted the expected kerf depth and microcrack formation for the laser parameters studied.