MEMS devices integrate mechanical components, electronics, sensors and actuators on a semiconductor material, chip, or wafer. They are built with advanced microfabrication and micromachining techniques to support a system-on-a-chip (SoC). An abbreviation for microelectromechanical systems, MEMS embeds very small devices in consumer electronics, medical devices, and industrial sensors. Typically, MEMS devices are found in computers, microphones and iPhones; lab-on-a-chip (LOC) devices, biosensors, and microrrays; and sensor chips for industrial and commercial applications. In the automotive industry, MEMS devices are used for both pressure sensing and inertial sensing. MEMS accelerometers, MEMS mirrors, MEMS valves, MEMS connectors, and MEMS switches for other applications are also available. Like other integrated circuits (ICs), MEMS devices are built in semiconductor materials such as silicon and with IC process sequences such as complementary metal-oxide semiconductor (CMOS), bipolar, and bipolar CMOS (BICMOS) processes. The fabrication and micromachining technologies that are used to produce these tiny devices include photolithography, deposition, and etching. MEMS foundries design and manufacture microelectromechanical devices on a contract basis, in amounts ranging from prototype to production quantities. Typically, these companies use MEMS processing equipment such as silicon etching tools, wafer grinders, lapping and polishing machinery, and planarization equipment. MEMS production equipment is used to manufacture MEMS devices such as accelerometers and gyroscopes for inertial sensing applications, and geophones for both seismic sensing and vibration sensing. There are many different types of MEMS devices, but several basic categories. These include fluidic MEMS, optical MEMS, bio-MEMS, and RF MEMS. Fluidic MEMS devices are used in flow and pressure sensors, pneumatic valves, and membrane pumps for biological, chemical, medical, and pharmaceutical applications. Optical MEMS devices include very small mirrors for scanning and imaging applications, and miniaturized connectors and switches for fiber applications. MEMS mirrors are low-cost, deformable devices with thousands of actuators and advanced microstructures. Typically, they are used to shape wave fronts. Bio-MEMS devices are used to analyze and measure biological matter for biomedical analysis and in total analysis systems (TAS). RF MEMS devices are also available. These tiny parts provide radio frequency (RF) functionality and include MEMS resonators, which vibrate in specific patterns to function as band-pass filters.