Characterization and simulation of PECVD and APCVD oxide step coverage

The step coverage of plasma-enhanced chemical vapor deposition (PECVD) and atmospheric-pressure CVD (APCVD) glass films has been studied experimentally and by computer simulation. An original method is proposed to characterize the step coverage of a deposition process. Based on the graphic representation of step coverage results on dimensionless diagrams, this method allows comparison of deposition techniques, as well as the quantification of the influence on step coverage of several parameters (step slope, underlying step material). Application of the method to the global evaluation of PECVD models is presented on two examples. The hemispherical model of the process simulator SAMPLE is not suited to the simulation of PECVD, whereas the TITAN 5 model leads to a good agreement with the experimental results. A predictive tool is thus obtained, which allows optimization of planarization processes by computer simulation