• Identical work

This talk aims to show the possibilities to build up micro electromechanical systems (MEMS) in a small scale research lab. Its size of 100 m^2 cleanroom keeps the flexibility to easily introduce new materials but nevertheless offers a set of standard procedures for UV lithography and UV depth lithography, wet etching, electroplating, PVD, dry etching, packaging and characterization, respectively. The installations are optimized for 100 mm wafers and low temperature (< 150°C) surface micromachining, for details see http://www.emk.tu-darmstadt.de/en/institute/equipment/. For instance, the apparatus enable the batch fabrication of 197 active MEMS chips with 5 mm x 5 mm outlines including large scale electrical connections for robust packaging, see SEM figure.

The technology foci are Direct LIGA and long term stable ultra-thick (200 µm .. 1.2 mm) functional materials based on epoxy resins. The combination of UV Direct LIGA (lithography, subsequent electroplating and final release of metal structures) and nanotechnology offer potential for new MEMS and NEMS.

Substrate materials currently comprise Silicon, glasses, ceramics and printed circuit board glass fiber reinforced plastic (FR4). Structures are made of Ni, Cu, Au, Cr, Al, epoxy resins like different SU-8 formulations, olycarbonate and combinations of those.

The MEMS made in this small scale research lab can be distinguished by structure geometries with out of plane metal wires. These posts show diameters of 100 nm .. 50 µm, lengths of 10 µm .. 400 µm keeping aspect ratios from 10:1 to 500:1. Furthermore, nano- and microwires can easily be combined with millimeter structures and all of them can be freely clamped.

The MEMS made in the small scale research lab offer the functionalities of inertial sensing (capacitively), gas flow sensing (thermally), out of plane actuation (electrostatically driven) and in plane actuation (electrothermomechanically with cN forces).