Next generation of TCAD environments for MEMS design

Most available MEMS design environments focus on the integrated behavioral simulation of electronic and mechanical components. The fabrication process is considered a fixed sequence of well-known steps, which can be purchased from foundries. Simulation models rely on the assumption of ideal process conditions and do not take into account tolerances or intra die variations. Recently there has been discussion that the gap between actual process results and that of predicted models are often out of a tolerable range. This leads to the demand of increased simulation accuracy for the most crucial process steps. The deviations of the comb structures in a resonator, which result from the tolerances in a Deep-RIE process, for example, can make the overall system design fail. To avoid these kinds of errors two things are needed: the technology provider has to know the parameter range of his process and be able to provide it to the designer without loosing his intellectual property. The designer in turn must be provided with a way to use this information to design a system which can perform in the range expected. In this paper we present the latest version of the TCAD environment BICEP3S (Braunschweigs Integrated CAD- Environment for Product Planning and Process Simulation). By using a central process database, which allows the exchange of all relevant process data it is able to overcome many of the mentioned obstacles. The database and process planning tool can be used by process developers to document changes in process settings and the influence of such changes on the process result. This information can then be used by the designers to set-up a simulation file for a detailed analysis of the impact of such parameter changes on the requested design. This will be shown by the example of silicon etching using an atomistic etch simulator.