Dry etch uniformity and optimization using graphical and DOE techniques

A uniform TEGAL 903E plasma oxide etch process, has been developed using a novel analytical technique. The process has been implemented successfully in the manufacturing arena. The novel analytical technique involves executing statistically designed experiments, then visually analyzing wafer uniformity topography maps. Modeling uniformity is usually done using a summary metric of standard deviation or normalized max-min values. This work demonstrates a weakness in this approach and presents a new strategy.