Study of the influence of process parameters on gate oxide degradation during contact etching in MERIE and HDP reactors

Abstract

Two designs of experiments (DOE) have been carried out, in a magnetically enhanced reactive ion etching (MERIE) reactor and in a high-density plasma (HDP) reactor, to determine the influence of pressure, bias power and overetch on gate oxide degradation. In both cases, we find that damage can be strongly reduced by increasing pressure. For the MERIE reactor, the model used for the DOE is suitable and gives the following tendencies: the damage level decreases for higher pressure and lower bias power, whereas the overetch seems to influence the results quite slightly. For the HDP reactor, the results show a strong pressure influence, with the same tendency as previously: the lower the pressure, the higher the damage level. In the analysis of the results, we pay special attention to the applicability of the DOE and propose explanations for the observed tendencies.