Rapid micro hole laser drilling in ceramic substrates using single mode fiber laser

This paper presents experimental results on rapid single mode fiber laser drilling of ceramic substrates. The materials under study are alumina and aluminum nitride with thicknesses ranging from 0.25 mm and 1.5 mm. Both the bore diameter and the drilling speed are optimized by varying the laser focus position, laser power, gas pressure and laser modulation scheme, respectively. Within a design of experiment approach we show that the focus position has the highest influence on the bore diameter and highlight the capability to drill sub-50 μm bore diameters with an almost vanishing taper (1.57 °) and good circularity (≤1.07) using modulated single mode fiber lasers. The required drilling time for, e.g. 0.25 mm alumina is as low as 0.1 ms with, in general, longer drilling times for AlN as compared to Al2O3. Using a pre-pigmenting technique the splatter after drilling is completely removed in an ultrasonic bath.