Comparison of patterned wafer defect detection tools for general in-line monitors

Manufacturer specifications for sensitivity and capture efficiency for pattern wafer defect inspection tools are usually based on data obtained under optimum conditions, using substrates with little process variation, and in some cases long inspection times. Requirements for general in-line monitors at most IC production facilities do not require maximum sensitivity. Key requirements at Motorola MOS 12 for general in-line monitors, when there is no previously identified defect type that must be detected, are zero nuisance defects, significant sample size, and reasonable speed and sensitivity. At startup of Motorola MOS 12, three types of pattern wafer defect inspection tools were purchased: KLA 2131, OSI 165, and Tencor 7600. This paper outlines the results of a study comparing defect detection sensitivity and capture rate for the three systems, given our requirements for general in-line monitors. Results from six steps in our process will be presented. This data was used, in part, to develop our strategy for in-line defect monitoring.