Challenges in nanometrology: high precision measurement of position and size

Abstract

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.

A Practical Positioning Method in End-Plate Surface Distance Measurement with Nano-Meter Precision

“…In order to ensure the length measurement accuracy, the length measurement system should use the frequency stabilized laser. Furthermore, the interference system should be placed in vacuum environment for length measurement with nanometer precision [8][9][10][11]. The experiment measurement repeatability was affected by laser wavelength stability.…”

“…where, L is the measured length, λ is laser wavelength, and ω0 is the radius of waist of laser beam. Since the laser source used for length measurement was a semiconductor laser and the laser beam directly output without any collimation, the beam waist radius of the laser is estimated to be 0.1 mm, δldif 0.1 nm for L 0.1 mm was obtained by Equation (8). Table 1 gives the information used for the measurement uncertainty evaluation.…”