Analog matching properties process dependency on MIM capacitors

A study on the effect of process fabrication for MIM capacitors analog matching performance was carried out, impacts from the MIM dielectrics, capacitor top and bottom metal materials, capacitor metal etch, wet cleaning, annealing process will be revealed by comparing the Pelgrom coefficients, i.e. the dependence of difference in capacitance of the matching pairs with respect to their corresponding square root of capacitor areas, the smaller the difference the better the matching. We have also investigated the related electrical properties, linearity as well as the reliability performance among the various process variants as assessed and reported in this evaluation study. The key area of matching dependency, and the process induced reliability concerns are identified. Optimization in process can be done to further improve the capacitors' analog performance.