Continuously Improving Methods for Increasing the Running Efficiency of Equipment in 300-mm Semiconductor Fabrication

Abstract

Overall equipment efficiency (OEE) is widely adopted in semiconductor manufacturing to assess and enhance equipment productivity. The rate efficiency, which is a major component of OEE, is utilized to evaluate the achievement of actual production rate to the equipment's theoretical production rate. However, the rate efficiency is significantly influenced by factors beyond the equipment and, therefore, is inadequate for deciding whether a low production rate is due to the equipment itself. Such an inaccurate evaluation of production rate of equipment usually results in productivity loss. Hence, this study develops a novel metric, called running efficiency (RUNE), to compare the actual and theoretical production rates of the equipment. The RUNE is not affected by the production environment and can be employed to determine sources of equipment's variation. Additionally, a RUNE management procedure is also proposed. The management procedure incorporates an automatic target-setting scheme to set the theoretical production time of every motion in equipment to obtain the RUNE value of equipment. An exponentially weighted moving average control chart is then utilized in the management procedure to monitor the RUNE value of equipment. A real case from a 300-mm fabrication in Taiwan is employed to demonstrate the effectiveness of the proposed method.