Combining an automatic material handling system with lean production to improve outgoing quality assurance in a semiconductor foundry

Abstract

This research uses a case study methodology to investigate ways of improving the outgoing quality assurance (OQA) processes of a 12-inch wafer foundry. It applies the value stream mapping method of lean production to analyse the wafer OQA processes. The study ensures that all outgoing wafers satisfy customers’ requirements without waste. In this paper, a current state map is used to locate potential waste and problematic process flows. Meanwhile, system simulation is adopted to construct the automatic material handling system and the equipment, transportation, and dispatching automation production module for the OQA processes—namely, the To-Be model and the future state map. The empirical results show that, for the To-Be model, the total lots of three customers per month increased from 3,106 to 3,719 pieces—about a 20% increase—and that the average product cycle time for customers A, B, and C dropped by 43.67%, 57.91%, and 58.39%, respectively. Furthermore, the operators’ utilisation rate increased from 61% of 10 operators on the day and night shifts to 87.26% of seven operators on the day and night shifts—about a 30% decrease of labour costs. Therefore, this study applies lean production (removing the non-value-added activities) and automation to improve the case company’s wafer OQA processes.