Research advances of femtosecond laser drilling microholes in hard and brittle materials

Abstract

The current demand for device miniaturization and high-density interconnections prompts high-precision microholes machining as a promising direction. Several applications employing microholes machining have been established that have given more attention to chip cooling, sensor diaphragm preparation, particle filtration, etc. Femtosecond laser drilling microholes technology has distinguished itself from other traditional laser processing methods due to its high precision, low thermal damage and controllable processing path. Currently, femtosecond laser drilling technology has made significant progress in the micro/nanoholes on hard and brittle materials. This paper reviews the mechanism and research progress in preparing microholes on different hard and brittle materials using femtosecond lasers. The effect of laser processing parameters on the quality of microholes processing is summarized and other impact factors such as different types machining strategies and auxiliary methods are assessed. The current limitations of femtosecond laser drilling on hard and brittle materials and its application in sensing, heat dissipation, and other fields are discussed.