Abstract
Control charts are widely applied to monitoring quality variation from stable status to instable status in many manufacturing lines. Large-scale integrated circuit(LSI) manufacturing requires to monitor thin film thicknesses, circuit pattern dimensions, particle count on a wafer and so on. This paper proposes a new monitoring method for particles on a wafer. If particles induce random location based on Poison distribution, the c-chart is applicable. However, actual particle generation is not dependent of Poison distribution and then the c-chart indicates many false alarms. The proposed method predicts particle-limited yield to apply the p-chart to monitoring particle data. The method uses data outputted by a particle inspection tool such as a particle location and a scattered light intensity with respect to each particle. Experiments show that the method reduces false alarms.
