Integrated ADI optical metrology solution for lithography process control of CD and OV

Integrated metrology in the lithography cluster is a promising solution to tighten process control. It is shown that optical CD metrology using YieldStar, an angular resolved scatterometer, meets all requirements in terms of precision, process robustness, throughput and matching to CD-SEM, the current tool-of-reference. The same metrology tool supports also diffraction-based overlay metrology. Using an appropriate sampling plan and the full scanner correction capabilities, overlay control can be improved. The throughput of the integrated tool is sufficient to support high volume sampling plans for combined CD and overlay monitoring and control, with 100% lot coverage.