Simple APDL implementation of a 3D FEM simulator for mutual capacitances of arbitrarily shaped objects like interconnects

摘要

This paper describes the implementation of an ANSYS Parametric Design Language (APDL) macro called CAMACO for the computation of capacitance matrixes of arbitrarily shaped 3D objects in arbitrarily distributed dielectrics via the conservation of field energies. APDL as the interface language of the general purpose FEM system ANSYS-Multiphysics~(TM) provides an exceptional high level of abstraction and enables the realization with acceptable effort. The most significant advantage of the described implementation is the utilization of the advanced 3D capabilities of ANSYS~(TM) to generate, edit and visualize realistically shaped ('non-Manhattan') 3D structures either by parametric description and/or graphical interaction (e.g. spaceball; VRLM models etc.) exceeding known solution. These features are especially helpful for initial principal design studies of potential structures. One typical application of CAMACO is the computation of capacitance matrixes for parasitic elements in DRAM memory cells. A 3D multi-level metal interconnect capacitance analysis of a potential trench capacitor 1GBit DRAM cell in 150nm minimum feature size is discussed.