A virtual metrology approach for maintenance compensation to improve yield in semiconductor manufacturing

Process condition was changed by preventative maintenance that may lead to the inconsistency of process output. In practice, process engineers have difficulties to discover the inconsistency that the defect wafer may have been produced before the next measurement. This study proposes a virtual metrology (VM) approach for maintenance compensation in semiconductor manufacturing. The tool process parameter streams were collected to predict the product metrology value, and a relation model was built to adjust the equipment settings for product recipe compensation. An empirical study in maintenance compensation of chemical vapor deposition (CVD) was conducted in a Taiwan semiconductor company for validation. The thickness difference caused by maintenance was reduced from 571 to 77 in training data and 564 to 210 in testing data. The results showed practical viability of the proposed approach and an intelligent system embedded with the developed algorithm has been implemented.