Recent years have witnessed the introduction of several new laser technologies for laser material processing. Particularly in micromachining processes, where excellent mode quality and high focusability are important for achieving small feature sizes, these new lasers are enabling emerging commercial applications. Due to the various combinations of laser wave-length, pulse energy, pulsewidth, and pulse repetition frequency among these lasers, both gross and subtle differences occur in the complex laser/material interaction physics. Consequently, variations occur in the quality of the micromachined features and the speed of the process, and empirical data are still the best means of comparison of these industrially significant effects.
In this study, we compare the drilling results obtained with six lasers of current industrial interest: frequency-tripled diode-pumped Nd:vanadate (355nm wavelength), frequency quadrupled diode pumped Nd:vanadate (266nm wavelength), KrF excimer (248nm) and three CO2-based laser technologies at wavelengths between 9.2 and 9.4 µm. We focus attention on drilling processes, where machining is often complicated by the material-ejection phenomena, particularly for deep holes. In a variety of materials, including ceramics and glasses, we examine the hole characteristics obtained and note the drilling speed possible with current commercially available lasers.