Femtosecond pulsed laser microfabrication of SiC MEMS microgripper

We report the capability of an ultrafast laser to pattern an electrostatic-comb-drive microgripper in the chemically difficult-to-etch 3C-SiC thin films. A microgripper with overall dimensions 1.2 mm×0.35 mm and a gap of 20 μm was designed and fabricated for the purpose of grasping and transporting microscale objects in hostile and harsh environments. Atmospheric pressure chemical vapor deposition was used to deposit thin films (∼2 μm) of 3C-SiC on 〈100〉 silicon substrates. A Ti:sapphire laser with 120 fs pulse width, 800 nm wavelength, and 1 kHz repetition rate was then used to perform “nonthermal” micromachining of thin films. Subsequent KOH anisotropic etching was used to dissolve the silicon substrate and release the gripper structures. The influence of laser pulse energy on the etch rate and quality of microfabricated grippers was examined and illustrated.