Microtechnologies for microsensors

Summary form only given. Silicon technologies are more and more widely used to manufacture, not only integrated circuits, but also microsensors. It has become a common practice to group under the title of "micromachining" all the processes more specifically used to manufacture 3D micromechanical components which are mainly developed for the needs of electromechanical microsensors. The main tools that can be used to manufacture 3D components (dimensions of the same order of magnitude in all directions) despite the fundamentally 2D characteristic of micro-technologies are anisotropy and selectivity of etching processes, with three main families of processes that are able to produce such structures: chemical anisotropic etching of single crystals; plasma etching, and sacrificial layer methods. Starting from few examples of microsensors which has been developed in LETI, we give a general idea of what is feasible with these processes.