Fault detection of the ion implanter using classification approach

In this paper, we propose a fault detection scheme for an ion implanter using the classification approach. We employ a previously developed hierarchical fuzzy rule based classifier (HFRBC) to classify the recipe of a working wafer in the ion implanter. The classification errors for various recipes of the HFRBC are treated as the accuracy of the classification result. Based on the classification results, we propose a warning signal generation criteria to minimize the probability of false alarm by excluding the possibility of electrical spikes and reducing the classification inaccuracy. We have tested the validity of our proposed warning signal for a 42-recipe case and obtained very successful results.