Processing and analysis of long-range scans with an atomic force microscope (AFM) in combination with nanopositioning and nanomeasuring technology for defect detection and quality control

This paper deals with a planar nanopositioning and -measuring machine, the so-called nanofabrication machine (NFM-100), in combination with a mounted atomic force microscope (AFM). This planar machine has a circular moving range of 100 mm. Due to the possibility of detecting structures in the nanometre range with an atomic force microscope and the large range of motion of the NFM-100, structures can be analysed with high resolution and precision over large areas by combining the two systems, which was not possible before. On the basis of a grating sample, line scans over lengths in the millimetre range are demonstrated on the one hand; on the other hand, the accuracy as well as various evaluation methods are discussed and analysed

Absolute Längenmessung in einem polarisationsoptischen Weißlichtinterferometer

Für die Untersuchung achromatischer Polarisationsoptiken zum Einsatz in der interferometrischen Längenmesstechnik wurde ein fasergekoppeltes Tandeminterferometer aufgebaut und getestet. Dabei lag der Schwerpunkt auf der Detektion und der rechnergestützten Verarbeitung der charakteristischen Interferenzsignaturen kurzkohärenter Lichtquellen

Weitere Entwicklungen zum 2 Photonen direkten Laserschreiben zur großflächigen Nanostrukturierung

Um hochpräzise und großflächige Mikro- und Nanofabrikation zu realisieren, wurde ein Aufbau zum 2 Photonen direkten Laserschreiben entwickelt. Nun sollen der Aufbau zu einem vollständigen Laserschreibsystem ausgebaut und weitere Entwicklungen vorgestellt werden

Two-photon direct laser writing beyond the diffraction limit using the nanopositioning and nanomeasuring machine

Since the first realization of two-photon direct laser writing (DLW) in Maruo et al. (Opt Lett 22:132-134, 1997), the manufacturing using direct laser writing techniques spread out in many laboratories all over the world. Photosensitive materials with different material properties open a new field for micro- and nanofabrication. The achievable structuring resolution using this technique is reported to be sub-100 nm (Paz et al. in J. Laser Appl. 24:042004, 2012), while a smallest linewidth of 25 nm could be shown in Tan et al. (Appl Phys Lett 90:071106, 2007). In our approach, the combination of DLW with the nanopositioning and nanomeasuring machine NMM-1 offers an improvement of the technique from the engineering side regarding the ultra-precise positioning (Weidenfeller et al. in Adv Fabr Technol Micro/Nano Opt Photon XI 10544:105440E, 2018). One big benefit besides the high positioning resolution of 0.1 nm is offered by the positioning range of 25 mm × 25 mm × 5 mm (Jäger et al. in Technisches Messen 67:319-323, 2000; Manske et al. in Meas Sci Technol 18:520-527, 2007). Thus, a trans-scale fabrication without any stitching or combination of different positioning systems is necessary. The immense synergy between the highly precise positioning and the DLW is demonstrated by the realization of resist lines and trenches whose center-to-center distance undergoes the modified diffraction limit for two-photon processes. The precise positioning accuracy enables a defined distance between illuminated lines. Hence, with a comparable huge width of the trenches of 1.655 [my]m due to a low effective numerical aperture of 0.16, a resist line of 30 nm between two written trenches could be achieved. Although the interrelationships for achieving such narrow trenches have not yet been clarified, much smaller resist lines and trench widths are possible with this approach in the near future

Phase-modulated standing wave interferometer

Standing wave interferometers (SWIs) show enormous potential for miniaturization because of their simple linear optical set-up, consisting only of a laser source, a measuring mirror and two standing wave sensors for obtaining quadrature signals. To reduce optical influences on the standing wave and avoid the need for an exact and long-term stable sensor-to-sensor distance, a single-sensor set-up was developed with a phase modulation by forced oscillation of the measuring mirror. When the correct modulation stroke is applied, the harmonics in the sensor signal can be used for obtaining quadrature signals for phase demodulation and direction discrimination

Heterodyne standing-wave interferometer with improved phase stability

This paper describes a standing-wave interferometer with two laser sources of different wavelengths, diametrically opposed and emitting towards each other. The resulting standing wave has an intensity profile which is moving with a constant velocity, and is directly detected inside the laser beam by two thin and transparent photo sensors. The first sensor is at a fixed position, serving as a phase reference for the second one which is moved along the optical axis, resulting in a frequency shift, proportional to the velocity. The phase difference between both sensors is evaluated for the purpose of interferometric length measurements

Resolution enhancement in Fabry-Perot interferometers through evaluation of multiple reflection using range-resolved interferometry

This work presents a novel approach for improving interferometer resolution with a relatively simple setup by combining the use of range-resolved interferometry and a high-finesse Fabry-Perot setup utilizing multiple reflections in the cavity to gradually increase the resolution. This approach could enable the measurement of small displacements with a potentially much higher resolution than current interferometry methods. A simple proof-of concept setup demonstrated the evaluation of up to four Fabry-Perot passes, while theoretically much higher sensitivity improvement factors should be possible