The influence of boundary locations on wiring capacitance simulation

The influence of boundary conditions on periodic wiring capacitance simulations is investigated. It is found that the wiring capacitance depends strongly on the boundary locations. The Neumann boundary condition is used at the planes of symmetry which bound the calculation region. For simulating a periodic wiring pattern, the Neumann boundary plane is usually placed at the center of an electrode. However, when the Neumann boundary plane is placed at the center of an insulator between neighboring electrodes, the simulated capacitance becomes 20% larger than that for the usual boundary location. This discrepancy is analyzed and a novel technique for calculating accurate capacitances is proposed