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Progress on Implementation of a CD-AFM Based Reference Measurement System



Ndubuisi G. Orji, Angela Martinez, Ronald G. Dixson, J Allgair


The National Institute of Standards and Technology (NIST) and SEMATECH are working to address traceability issues in semiconductor dimensional metrology.  In semiconductor manufacturing, many of the measurements made in the fab are not traceable to the SI definition of the meter. This is because a greater emphasis is often placed on precision and tool matching than accuracy. Furthermore, the fast pace of development in the industry makes it difficult to introduce suitable traceable standard artifacts in a timely manner. To address this issue, NIST and SEMATECH implemented a critical dimension atomic force microscope (CD-AFM)-based reference measurement system (RMS). The system is calibrated for height, pitch, and width and has traceability to the SI definition of length in all three axes. Because the RMS is expected to function at a higher level of performance than inline tools, the level of characterization and handling of uncertainty sources is on a level usually seen for instruments at national measurement institutes. We have implemented a performance monitoring system to help us check the long-term stability of the calibrations. In this paper, we discuss progress in improving the uncertainty of the instrument and the details of our performance monitoring. We also present a method for accounting for some of the uncertainty due to the higher order tip effects.
Proceedings Title
Proceedings of SPIE
Conference Dates
February 19-24, 2006
Conference Location
San Jose, CA
Conference Title
Metrology, Inspection, and Process Control for Microlithography XX


CD-AFM, higher order tip effects, reference measurement system, traceability


Orji, N. , Martinez, A. , Dixson, R. and Allgair, J. (2006), Progress on Implementation of a CD-AFM Based Reference Measurement System, Proceedings of SPIE, San Jose, CA (Accessed April 17, 2024)
Created March 1, 2006, Updated February 19, 2017