Elliptical beam speeds laser cutting

Using patented technology from JMAR Technologies (San Diego, CA) in which an elliptical laser beam is used to improve material ablation, scientists at Coherent (Santa Clara, CA) and HBL (Daejeon, Korea) have determined the optimum focal-spot geometry for diode-pumped solid-state Q-switched lasers, which will improve singulation (cutting) of thin silicon wafers.

In a series of experiments on silicon wafers less than 200 µm thick, changing a circular spot to an elliptical one (by inserting a cylindrical lens in the optical path before the scan lens) enabled a cutting-speed increase from 16.7 to 62 mm/s for a 100-µm-thick wafer when the major axis of the ellipse was aligned along the cutting direction. The elliptical beam apparently optimizes the laser fluence for a given pulse repetition rate and improves the material-removal rate for silicon. Contact Leonard Migliore at leonard.migliore@coherent.com.