A Beginner's Guide to MEMS Processes
This guide is intended for people new to microelectromechanical systems (MEMS) technology. It gives a brief overview of the technology and some of the methods used to create microstructures. The guide is not intended as a comprehensive, all inclusive, description. It is merely a short introduction to the basic fundamentals of the technology. You may also want to refer to our MEMS glossary.
MEMS technology is based on a number of tools and methodologies, which are used to form small structures with dimensions in the micrometer scale (one millionth of a meter). Significant parts of the technology have been adopted from integrated circuit (IC) technology. For instance, almost all devices are built on wafers of silicon, like ICs. The structures are realized in thin films of materials, like ICs. They are patterned using photolithographic methods, like ICs. There are however several processes that are not derived from IC technology, and as the technology continues to grow the gap with IC technology also grows.
There are three basic building blocks in MEMS technology, which are the ability to deposit thin films of material on a substrate, to apply a patterned mask on top of the films by photolithograpic imaging, and to etch the films selectively to the mask. A MEMS process is usually a structured sequence of these operations to form actual devices. Please follow the links to read more about deposition, lithography and etching.