@Xiaolin Wu: The MiM caps are roughly 2fF/um^2 (that's area capacitance and neglects fringe capacitance, so the total capacitance will be a bit higher than just the area calculation). If you use the parameterized device generator in magic to create the MiM caps (or just to run the calculations for you), it will give you the total capacitance, incorporating both area and fringe, so it will be pretty accurate.