An effective SPC approach to monitoring semiconductor quality data with multiple variation sources

In semiconductor manufacturing, post-process metrology and statistical monitoring of quality data are critical to ensure a high yield and good quality products. Effective SPC charting can detect process excursions and provide early warning on possible process faults. Therefore, it is important to design SPC charts such that process shifts, small or large, can be detected early and accurately, while the number of false alarms can be cut down to an acceptable level.