MEMS devices have evolved in the last 10 years from an academic and laboratory curiosity to a viable technology with potential widespread application. Significant advancements are now being made to package and manufacture MEMS devices for the commercial and consumer marketplace. In MEMS devices that are silicon-based, integrated circuit fabrication techniques are used to reduce the size of mechanical features to the miniature dimensions of microelectronics. Integrating these mechanical features with electronic circuits on the same chip offers a wealth of new product opportunities not possible with conventional design and manufacturing approaches. Initially MEMS referred to silicon-based devices but today refers to a complete miniature device that may or may not be silicon based. Also MEMS devices have expanded beyond the integration of electronic and mechanical functions. Today devices can have mechanical, optical, fluidic, and thermal functions in some combination with each other and generally integrated with electronic functions. MEMS technology can be used to fabricate extremely sensitive sensor for a variety of applications including pressure, sound, mass, motion, acceleration, rotation, flow, chemicals, vibration, and temperature. The technology can also be used to fabricate field-emission tips and probes for use in high-brightness specialized displays, electron-beam sources, information storage applications and precision temperature sensing. Actuators can be fabricated for use in optical switching, flow control, micropositioning, adaptive optics, and displays. Finally, a variety of passive, 3D, micromechanical structures can be fabricated with applications in telecommunications, electronic components, and sensors.