Patent Number: 6,251,698

Title: Method for making a machined silicon micro-sensor

Abstract: A process for the production of microsensors machined in silicon, and in particular accelerometers for applications of assisting with navigation in aircraft, and pressure sensors. In order to improve the production of certain active parts of the sensor, and in particular of a beam forming a resonator, which needs to have well-controlled width and thickness characteristics, the following procedure is adopted. A beam having a thickness equal to the desired final thickness, and a width greater than the desired final width, is produced by micromachining the silicon on a first plate, the beam being covered on its upper face by a mask defining the desired final width. The plate is assembled with another plate. The two faces of the beam are oxidized in order to cover them with a thin protective layer. The thin protective layer on the upper face is removed, by vertical directional etching, without removing the mask already present. The silicon in the area exposed by the preceding operation is attacked by a vertical directional etch on the upper face, until the entire part of the beam not protected by the mask is eliminated, and the beam having the desired width is thus formed.

Inventors: Lefort; Olivier (Valence, FR), Thomas; Isabelle (Valence, FR)

Assignee: Sextant Avionique

International Classification: B81B 3/00 (20060101); B81C 1/00 (20060101); G01P 15/125 (20060101); G01P 15/08 (20060101); H01L 021/00 ()

Expiration Date: 06/26/2018