OYSTER, a 3D structural simulator for microelectromechanical design

OYSTER simulated the geometric effects of sequential IC (integrated circuit) process stages, including patterning of photoresists with planar masks, in order to produce three-dimensional polyhedral representations of all material structures in a design cell after each process stage. It has been developed for IC simulation but is applicable to microelectromechanical systems manufactured using similar processes. The polyhedral models may be used with various analytic procedures as sources of geometric data for finite-element calculations, or they may be subjected to interference calculations, or inspected to detect structural anomalies. As used in IC simulations, OYSTER provides the ability to introduce worst-case or stochastic manufacturing variations in mask alignment, etch depth, or deposition thickness. The author presents examples of variations in mask alignment and calculates resultant variations in center of gravity and moments of inertia for simple micromechanical objects