An international length comparison using vacuum comparators and a photoelectric incremental encoder as transfer standard

Tiemann, I; Spaeth, C.; Wallner, Gernot M.; Metz, G; Israel, W.; Yamaryo, Yasuyuki; Shimomura, Toshitaka; Kubo, T.; Wakasa, T.; Morosawa, Tetsuo; Köning, Rainer; Flügge, Jens; Bosse, Harald

doi:10.1016/j.precisioneng.2007.02.003

Cited by 41 publications

(24 citation statements)

References 10 publications

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“…Furthermore, an international length comparison with two other industrial 1D vacuum comparators using this 280 mm encoder as a transfer standard was carried out successfully. A maximum difference of only 5.5 nm, which is in the order of 2x10 -8 and in agreement within the quoted measurement uncertainties, which ranged from 3.2 nm to 6 nm, was obtained [6].…”

Section: Introductionsupporting

confidence: 88%

“…For the investigations reported on here, the scales were mounted on the manually operated sample supports, which have already proved their performance during the measurements of incremental encoders [5,6]. The scales were aligned vertically so that the surface at the support points are in the focal plane by using an optical probe and the pile of gage blocks used to determine the exact height of the focal plane as described in section 3.3.…”

Section: Line Scale Measurementsmentioning

confidence: 99%

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Achievement of sub nanometer reproducibility in line scale measurements with the nanometer comparator

2007

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Due to the discussed introduction of double patterning techniques the overlay and registration metrology requirements in advanced lithography will drastically increase so that reference metrology tools need to be developed further to be able to follow the resulting tightening of the specifications. Therefore, the PTB further develops the Nanometer Comparator, a 1D vacuum comparator, which already has proven its performance during the measurements of incremental encoders. The implementation of the angular control loops decreases the angle deviations of the measurement carriages down to 0.15 µrad, which led to a reduction of the contribution of the Abbe errors to the measurement uncertainty to insignificant levels. Changes in the illumination and alignment of its optical microscope resulted in an improved defocus behaviour, which consecutively reduced the reproducibility (1 σ) of measurements of high quality scales in the order of 1 nm. Therefore an expanded measurement uncertainty of below 5 nm has been achieved.

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Section: Introductionsupporting

confidence: 88%

Section: Line Scale Measurementsmentioning

confidence: 99%

Achievement of sub nanometer reproducibility in line scale measurements with the nanometer comparator

2007

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“…2 illustrates the measurement loop of the Nanometer Comparator using four different interferometer beams and the compensation principle of the residual guiding deviations, for further details see [1]. The performance of the Nanometer Comparator was proven in an international comparison of three vacuum length comparators using a 280 mm incremental length encoder as a transfer standard [2]. The measurement results of this comparison agreed within 2·10 -8 .…”

Section: Nanometer Comparatormentioning

confidence: 78%

Challenges in nanometrology: high precision measurement of position and size

Bosse

Bodermann

Dai

et al. 2015

Tm - Technisches Messen

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This contribution describes recent developments of the PTB in high precision position and size metrology as support for different nanotechnology applications. It will be shown how measurement uncertainties of about 1-2 nm for 1D-position of graduation lines on 152 mm photomasks (6''), or on line scales and incremental encoders of about 300 mm length have been achieved. The measurement of the size of nanoscale features represents additional challenges, because in addition to the length metric, also the location of opposite feature edges has to be precisely determined. In addition to other feature size or CD metrology techniques applied at PTB, a recent development which uses transmission electron microscopy in the traceability chain of AFM CD measurements will be described. The uncertainties achieved for CD measurements on high quality Si line structures are U 95% = 1.6 nm.

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“…The overall agreement of the traceable length measurement results was observed to be within 5.5 nm over 280 mm, i.e. the relative agreement corresponds to 2·10 -8 [15]. After this comparison was completed, the PTB could further improve the measurement performance of the Nanometer Comparator, especially by fully activating the control of the residual angular deviations of the slide movement.…”

Section: Measurement Performance On Incremental Length Encodersmentioning

confidence: 79%

Development of a 1.5D reference comparator for position and straightness metrology on photomasks

Flügge

Köning

Weichert

et al. 2008

Photomask Technology 2008

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The so-called Nanometer Comparator is the PTB vacuum length comparator which has been developed for high precision length metrology on measurement objects with micro-and nanostructured graduations, like e.g. line scales, incremental encoders or photomasks. The Nanometer Comparator allows to achieve smallest measurement uncertainties in the nm-range by use of vacuum laser interferometry for the displacement measurement. We will report on the achieved measurement performance of this high precision vacuum length comparator and the already started developments to substantially enhance its measurement capabilities by additional straightness measurement capabilities. The enhanced Nanometer Comparator will provide traceability for photomask pattern placement measurements in industry, also facing the challenges due to the increased requirements on registration metrology as set by the introduction of new lithography techniques like double patterning methods.

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An international length comparison using vacuum comparators and a photoelectric incremental encoder as transfer standard

Cited by 41 publications

References 10 publications

Achievement of sub nanometer reproducibility in line scale measurements with the nanometer comparator

Achievement of sub nanometer reproducibility in line scale measurements with the nanometer comparator

Challenges in nanometrology: high precision measurement of position and size

Development of a 1.5D reference comparator for position and straightness metrology on photomasks

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