Product Code: ICAL05_M201

High Power DPSS Laser Micromachining of Silicon And Stainless Steel for Device Singulation
Authors:
Martyn Knowles, Oxford Lasers Ltd.; Abingdon, Oxon Great Britain
Presented at ICALEO 2005

We describe recent high power diode-pumped solid-state (DPSS) laser micromachining results of commonly used industrial materials such as silicon and stainless steel. Frequency upconverted lasers were used at 532nm and 355nm. Increasing demand for high volume production of miniaturised devices for precision applications has recently placed much emphasis on ultrafast laser micromachining of these materials. Nevertheless industrially robust high power nanosecond DPSS lasers are shown to compete well resulting in good edge quality features and higher processing speed. We discuss the benefits of high laser intensity (GW/cm2) on target for efficient laser microfabrication. At such high irradiance conditions material properties are approaching their critical limits and ablation mechanisms are becoming even more complicated but can be exploited to our advantage in particular for microdrilling and microcutting small feature sizes in the order 10-20 m and high aspect ratios of up to 20:1. Multilayer structures with thickness up to 1.5mm can be machined efficiently this way. Cutting and drilling rates are presented and a comparative study of the limitations of long and short laser pulse duration in the 30-300ns range is discussed. The application of this technology to device singulation for electronic and power devices will be reported.