Abstract
Failure Mode and Effects Analysis Method (FMEA) is widely used in the semiconductor process improvement activities, including the Risk priority number (RPN) which is used to determine the impact of failure mode on the system basis. The risk priority number supports decision-makers to make the correct judgment to avoid unnecessary waste on improvement and missed opportunity to improve the high-risk crisis. But the traditional RPN method has high repetition, ineffective order comparison on Severity, Occurrence, Detection (SOD), and no account for the failure modes of each project and the failure causes, such as direct and indirect relationships. Therefore, this study proposes a method that combines Grey Relational Analysis (GRA) and Decision Making Trial and Evaluation Laboratory (DEMATEL), to solve the problem of the traditional RPN. This methodfirst uses GRA method to revise the risk priority number. In order to find the right weight between SOD and reduce RPN repetition rate; it sorts by DEMATEL method to improve the direct and indirect relationship between Failure Mode and Cause of Failure, thereby bringing the risk more close to the real needs. Finally, his method applies to two real semiconductor process improvement cases. The effectiveness evaluation through the Control Plan confirms the validity of this method which performs better than the traditional RPN, and provides more reasonable information for decision-makers as a reference.