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Publication Citation: Towards Accurate Feature Shape Metrology

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Author(s): Ndubuisi G. Orji; Ronald G. Dixson; B Bunday; J Allgair;
Title: Towards Accurate Feature Shape Metrology
Published: March 22, 2008
Abstract: 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: Proceedings of SPIE, Metrology, Inspection, and Process Control for Microlithography XXII
Volume: 6922
Issue: 2
Pages: pp. 692208.1 - 692208.9
Location: San Jose, CA
Dates: February 22-29, 2008
Keywords: sidewall angle; critical dimension atomic force microscope; uncertainty
Research Areas: Metrology, Nanomanufacturing, Manufacturing