Sapphire micromachining with UV nanosecond lasers

Abstract

For a long time CO2 lasers have been the laser of choice for all kinds of processing applications due to their power/cost ratio. CO2 lasers in sapphire create a classic melt pool which can be blown out to achieve a full cut which is often too crude for the semiconductor applications. Pulsed UV lasers provide the opportunity to machine with much finer detail. The lack of excess heat adds another benefit. Each pulse removes a small amount of material but the high repetition rate turns it into a fast process. This paper explores the use of 355nm ultraviolet Q-switched Nd:YAG lasers with powers up to 22W and 1.2mJ pulse energy for micromaching Sapphire.