Microfabrication of MOEMS (also known as optical MEMS) is the process of creating a micromachine and can be considered as the last of three major phases. The first phase consists of optical or functional design, where the geometry and optical characteristics of the MOEM device are determined, based on the desired performance and optical properties of the surface. The second phase is the electromechanical design of the MOEM device. In this phase, mechanical and electronic calculations are performed, based on material characteristics such as stiffness and resistivity. The third phase consists of processing, or microfabrication, where the patterning, material deposition, and etching steps are performed in a sequential manner resulting in the desired device with the needed performance. In this chapter we will focus on microfabrication, the last phase of MOEM realization. Other publications have described different aspects of microfabrication for optical applications in some detail.
We now briefly introduce the most common microfabrication methods, which will then be discussed in some detail in the following sections of this chapter. Certain fabrication steps common to these methods will then be described. Finally, some more atypical yet promising fabrication techniques will be mentioned.
A micro-electro-mechanical system (MEMS) includes various electrical and mechanical mechanisms, such as magnetic, fluidic, thermal, and electromagnetic mechanisms. The low cost of MEMS, due to their large-volume manufacturing process akin to the one used for integrated circuits, makes them attractive for many applications. Arguably, optical applications have a compelling edge over others. Due to the extremely small size of the MEMS structures, they generally are not capable of producing actuators with the large forces required for moving objects of sizable mass. Thus moving light, which does not possess mass, is an ideal application for MEMS actuators.
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