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Towards Accurate Feature Shape Metrology



Ndubuisi G. Orji, Ronald G. Dixson, B Bunday, J Allgair


Over the last few years, the need for shape metrology for process control has increased. A key component of shape metrology is sidewall angle (SWA). However, few instruments measure SWA directly. The critical dimension atomic force microscope (CD-AFM) is one such instrument. The lateral scanning capability and the shape of the CD-AFM probe enable direct access to the feature sidewall. This produces profile information that could be used as a process monitor. Due to their relative insensitivity to material properties, CD-AFMs have been used as reference measurement systems (RMS) for measurands such as width. We present a technique for calculating the uncertainty of sidewall angle measurements using a CD-AFM. We outline an overall calibration strategy; address the uncertainty sources for such measurements, including instrument-related, and parameter extraction related, and how the calibration is transferred to workhorse instruments.
Proceedings Title
Proceedings of SPIE, Metrology, Inspection, and Process Control for Microlithography XXII
Conference Dates
February 22-29, 2008
Conference Location
San Jose, CA


sidewall angle, critical dimension atomic force microscope, uncertainty


Orji, N. , Dixson, R. , Bunday, B. and Allgair, J. (2008), Towards Accurate Feature Shape Metrology, Proceedings of SPIE, Metrology, Inspection, and Process Control for Microlithography XXII , San Jose, CA (Accessed February 23, 2024)
Created March 22, 2008, Updated February 19, 2017