ArF excimer laser micromachining of Pyrex, SiC and PZT for rapid prototyping of MEMS components

The ablation process has been characterized in the past for a number of laser sources in silicon (Si) micromachining. However, very few results can be found in the literature for excimer laser technology at 193 nm on Si and even fewer for other materials like piezoceramics (PZT) and silicon carbide (SiC). This work presents a parametric study of the dynamic interaction between the machining parameters involved in the ablation of materials with an ArF excimer laser using a mask dragging approach. The influence of the fluence, the repetition rate of the laser and the linear speed of the sample on the etch rate of material are quantified by experimental results for three different materials (Si, PZT and Pyrex). The main tendencies are discussed and supported with experimental measurement of trench profiles. The results obtained from ablation are then related to the optical and mechanical properties of materials. The interdependence between machining parameters, materials properties and the etch rate of materials is demonstrated. Optimal ranges of parameters are identified and then used to micromachine SiC, in addition to the previous materials. Two case studies are presented to demonstrate the potential complementarity of excimer laser micromachining systems with conventional lithographic microfabrication techniques for MEMS prototyping.