MEMS is an acronym for Micro-Electro-Mechanical Systems but is also referred to as micromachines (in Japan), or micro systems technology – MST (in Europe). The micro system components have dimensions in a range of 1 µm to 100 µm, while the complete devices have sizes up to a few millimeters. MEMS allow the miniaturization of existing devices, provide new functionality using physical principles that do not work at larger scale and enable development of tools to operate in the micro-world.
MEMS devices can be sensors, actuators or simple structures like cantilevers, gearwheels or other mechanical parts. Well-known examples for MEMS are accelerometers, gyroscopes, pressure sensors, bio-sensors, micro pumps, micro valves etc. A subsection of MEMS are MOEMS (Micro-Optical-Electrical-Mechanical-Systems) devices, which combine MEMS with Micro-Optics. Most famous MOEMS device is the DMD® micro display developed by Texas Instruments. Other MOEMS devices are optical switches, optical modulators or optical interconnects.
The fabrication of MEMS is based on semiconductor process technology, consisting of deposition of material layers, patterning by photolithography and etching to produce the required shapes. Bulk Micromachining is a technology where the whole thickness of the silicon is used to build microstructures by applying various etching processes. Surface Micromachining allows monolithic microsystems in which the electronic and the mechanical components are combined on the same substrate. This can be accomplished by deposition and etching of different structural layers on top of the substrate. Another approach is to create HAR (High Aspect Ratio) structures in silicon by DRIE or in thick photoresists like SU-8 or MR-DWL using UV-LIGA.
For all fabrication methods, lithography is required to create etch mask on silicon or HAR structures in thick photoresists. Direct Write Lithography allows very fast prototyping of MEMS devices. Heidelberg Instruments recommend the µPG, DWL and VPG series of Maskless Lithography Systems.
Photomasks required for high volume production of MEMS can be fabricated with very short exposure times and high quality with our VPG series of systems.