Traceability of the F25 vision system for calibration of grated structures with submicron accuracyv

Abstract

We have investigated the uncertainty sources that affect the traceability of dimensional measurements using the VIScan of the Zeiss F25 coordinate measuring machine (CMM). Our experimental results on line-width measurements are promising, having a repeatability below 120 nm and moreover they are reproducible for all light settings investigated. The comparison with the measurements performed on a facility used for line-scale calibrations provides very good agreement. At present we can report an uncertainty below 0.45 µm for line-width calibrations. This would be the first traceable F25 VIScan, and to our knowledge one of the first truly traceable vision systems for line-width calibrations.

Evaluation of an optical coordinate measuring machine for measuring grated structures

“…The Zeiss F25 CMM is shown in figure 1, with the optical objective (ViSCAN) seen in more detail in the picture on the right. The ViSCAN has a measurement volume of 100 × 100 × 100 mm 3 . The manufacturer specifies a probing tolerance of 0.6 μm for the objective with a magnification of 10× according to VDI 2617-6.…”

“…After each alignment step the position of the camera with respect to the scale is stored manually. The uncertainty that has been realized by this facility is for the pitch distance 100 nm + 1 × 10 −6 • l [3,9] and 0.4 μm + 2 × 10 −6 • l for feature-width calibrations, where l is the length of scale.…”

“…Based on this background, we have investigated the possibilities of using a commercial optical CMM, in particular our Zeiss F25 optical CMM for precise quantitative measurements. Initial results of this investigation have already been published elsewhere [3]. This paper aims to present an inventory of the uncertainty sources of the Zeiss F25 optical CMM and to make the user aware of the magnitude of the error sources and of the necessity of a measurement procedure to avoid faulty results when using commercial vision systems.…”