COLLECTIVE WET ETCHING OF A 3D MONOLITHIC SILICON SEISMIC MASS SYSTEM

We present a simple two-step etching process based on anisotropic wet etching of (100) silicon. As one example a system of three seismic mas ses on one chip has been fabricated. All three masses are symmetricall y suspended by four high aspect ratio beams. The highly symmetrical de sign minimizes mechanical cross-sensitivities. Moreover, the three dev ices exhibit almost perfect rectangular alignment due to the orientati on along the (100) directions of the silicon crystal. Besides experime ntal results, design rules for the photolithography-masks are presente d.