MEMS (Micro-Electro-Mechanical Systems) are devices that consist of micro system components with dimensions in a range of 1 µm to 100 µm. MEMS facilitate 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 may present as complex machines such as sensors or actuators, or as simple structures like cantilevers, gearwheels or other mechanical parts.
Well-known examples are accelerometers, gyroscopes, pressure sensors, biosensors, micro pumps, micro valves etc. A subsection of MEMS are MOEMS (Micro-Optical-Electrical-Mechanical-Systems) devices, which combine MEMS with Micro-Optics: for example 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. For all fabrication methods, be it bulk or surface micromachining, lithography is required to create etch mask on silicon or high-aspect ratio structures in thick photoresists. Here, our Direct Write Lithography is the ideal technology to accomplish rapid prototyping of MEMS devices.
High-aspect ratio gear wheel
The image shows a gear wheel in 800 µm thick SU-8. The structure has been created with the High-Aspect Ratio Mode of the MLA150. This allows the fabrication of structures with vertical sidewalls in very thick resist layers.
Another example of a gearwheel exposed into SU-8. The resist here had a thickness of 90 um; the resulting aspect ratio is > 40:1. - Courtesy of P. Pittet and N. Terrier (INL) - Université Lyon 1
Any of our direct writing systems MLA, DWL, and VPG+ may be the perfect tool of choice for your MEMS application, depending on your precise requirements. 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. Please contact us for a consultation.
Get in touch with us for more information about our products and services, answers to questions about our technology and everything else about Heidelberg Instruments.