Experimental study on hole drilling in aluminum nitride using laser processing

Aluminum Nitride (AlN) is a ceramic material that combines excellent thermal conductivity with outstanding electrical insulation properties, making it an ideal substrate for next-generation electronic components such as power modules, radio-frequency (RF) devices, and LED packaging. As the miniaturization and performance requirements of electronic systems increase, the demand for precise micromachining of AlN has grown accordingly. However, its inherent hardness and brittleness present significant challenges for conventional mechanical machining, often leading to undesirable effects like microcracking, tool wear, and dimensional inaccuracy. To overcome these limitations, ultrashort pulsed laser micromachining has emerged as a highly promising approach. This technique enables non-contact, high-precision processing with negligible thermal damage, owing to the ultrashort duration and high peak intensity of the laser pulses. In this study, microholes are fabricated on AlN substrates using an ultrashort pulsed laser, with a focus on optimizing laser processing parameters including the number of scans (NOS), pulse repetition rate, and focal plane position. The influence of these parameters on the resulting hole geometry, aspect ratio, and surface morphology is systematically investigated. Post-processing analyses using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) are performed to assess the microstructural quality and elemental distribution around the laser-ablated regions.