Effect of Laser Beam Focusing Adjustment on the Processing Quality of Aluminum Nitride Ceramic Micro-Holes

Abstract

The Gaussian laser beam was used to drill micro-holes with a diameter of 500μm on a 0.15mm thick aluminum nitride (AlN) ceramic. The geometry, processing quality, and surface fusion of the micro-holes were studied. The fusion recast layer at the edge of the hole is thick, the inner wall of the hole has a lot of slag, and the side wall of the laser entrance area is seriously inclined. Through spatial reshaping and focusing of Gaussian light, Bessel light with higher energy density, greater depth of focus, and smaller beam spot was achieved and used to perforate AlN ceramics. The fusion recast layer at the periphery and inner wall of the hole are both very thin, and the taper of the hole is very small. These results show that the focusing adjustment of the laser beam has a significant impact on the processing quality of AlN ceramic micro-holes.