Micromechanics for actuators

Fabrication processes for microactuator construction must provide the capability to achieve 3- D geometries with a large material base while being able to benefit from the low cost economy of scale of batch processing. These attributes are provided in part by the basic LIGA process originating in Germany which is able to form high aspect ratio metal components up to 500 micrometers in thickness with very low vertical run-out and is compatible with microelectronic processing. The process has been extended to allow geometries with thicknesses up to 1 cm via a low-strain performed photoresist sheet and solvent bonding with x ray exposure via the 2.5 GeV National Synchrotron Light Source (NSLS). Such results enable batch fabrication of parts suitable for larger precision engineered actuators and mechanisms. To demonstrate the extended process capabilities a magnetic micromotor has been constructed using electroplated permalloy and assembled LIGA defined components. The low-inertia of the small rotor sizes is demonstrated by a stepping micromotor with a 150 micrometers diameter rotor which achieved maximum rotational speeds over 150,000 rpm.