Nanosecond Laser Experiments of Microstructure Adhesion Reduction

Abstract

Due to the small size of structures in modern microdevices, surface forces can create undesirable adhesion between microstructures, which is referred to as stiction. Prior investigations have used ultrashort-pulse lasers to recover stiction-failed microcantilevers. The current experiments study the use of a 400 ns, 1064 nm, Nd:YAG laser to free polycrystalline silicon microcantilevers stuck to the underlying substrate. The results show that a Nd:YAG, 1064 nm laser is capable of recovering failed microstructures with yields exceeding those reported in earlier studies. Yields of 100 percent for cantilevers up to 1 mm in length were demonstrated for several laser operating conditions. The yields are strongly dependent on laser fluence and slightly dependent on exposure time, with a single-shot at 160 mJ/cm2 resulting in yields around 60 percent.