THE METHOD OF MAKING A PERIODIC TIME OF PREVENT MAINTENANCE IN SEMICONDUCTOR MANUFACTURING

摘要

A method for setting a preventive maintenance period of a semiconductor production line is provided to manage systematically preventive maintenance by optimizing the preventive maintenance period. Each process apparatus defines and stores automatically the same product which is manufactured prior to and posterior to the preventive maintenance. A storing process is performed to store a yield of products which are manufactured prior to and posterior to the preventive maintenance. The effect of the preventive maintenance is grasped automatically by comparing the measured result and the result of the yield prior to and posterior to the preventive maintenance. A pair of preliminary defect sample and preliminary normal sample are defined and stored. A T-square value is calculated by using a statistical method. A preventive maintenance period is set by grasping a variation of T-square value.