Processing thin silicon with ultrashort-pulsed lasers: creating an alternative to conventional sawing techniques

摘要

When processing thin silicon, an important workpiece category in modern IT industry, femtosecond laser pulses enable to create cuts and also holes of utmost precision. This could contribute to the ongoing miniaturization by reducing back-end processing resolutions. However, it bears special challenges: On the one hand, decreasing material thickness involves chipping effects and raises general handling questions. On the other hand, laser processing of silicon generally involves debris effects which are hard to handle in comparison to other common materials. In addition, processing speeds are usually still significantly lower than those of cutting with conventional mechanical methods. Therefore an overview of influences will be given that are of special interest for the processing of thin silicon with ultrashort-pulsed lasers. To demonstrate the competitiveness of the process in the near future, general advantages of this technique will be explained. Methods that have improved quality in case of chipping and debris and at the same time increased the processing speed will be presented.