Klaus Hasche

Bio: Klaus Hasche is an academic researcher. The author has contributed to research in topics: Scanning probe microscopy & Abbe error. The author has an hindex of 5, co-authored 8 publications receiving 241 citations.

Metrological large range scanning probe microscope

Abstract: We describe a metrological large range scanning probe microscope (LR-SPM) with an Abbe error free design and direct interferometric position measurement capability, aimed at versatile traceable topographic measurements that require nanometer accuracy. A dual-stage positioning system was designed to achieve both a large measurement range and a high measurement speed. This dual-stage system consists of a commercially available stage, referred to as nanomeasuring machine (NMM), with a motion range of 25 mm×25 mm×5 mm along x, y, and z axes, and a compact z-axis piezoelectric positioning stage (compact z stage) with an extension range of 2 μm. The metrological LR-SPM described here senses the surface using a stationary fixed scanning force microscope (SFM) head working in contact mode. During operation, lateral scanning of the sample is performed solely by the NMM. Whereas the z motion, controlled by the SFM signal, is carried out by a combination of the NMM and the compact z stage. In this case the compact z...

Improving the performance of interferometers in metrological scanning probe microscopes

Abstract: The traceability of metrological scanning probe microscopes (MSPMs) is achieved in most cases by laser interferometers. Different means have been adopted to account for the nonlinearity of those interferometers. The thorough investigation of an existing MSPM shows the necessity of interferometrical position measurement with real time full-bandwidth nonlinearity correction. The paper demonstrates that the ellipse parameters of Heydemann nonlinearity correction are sufficiently stable and position independent. This is used in reducing the signal processing time by calculating the ellipse parameters in advance and fixing them during real time nonlinearity correction. As a result, a real time signal processing system with the ability of executing Heydemann correction in 0.32??s and a complete demodulation in 2.2??s is designed and implemented. It reduces the residual nonlinearity of interferometers from about 3.5 to <0.3?nm. Some measurement results of a flatness standard illustrate the effectiveness of this new method.

Measurement of micro-roughness using a metrological large range scanning force microscope

Abstract: A new method for traceable measurement of micro-roughness by using a newly developed metrological large range scanning force microscope (LR-SFM) is described. The LR-SFM has an Abbe error free design and direct interferometric position measurement capability, and is capable of measuring samples in a volume of 25 mm × 25 mm × 5 mm along x, y and z axes. The instrumentation and several important design concepts are introduced in this paper. Measurement results of a plane glass and a micro-roughness standard have illustrated that the instrument has a low noise level of Ra = 0.58 nm and good measurement repeatability. Furthermore, a group of comparison measurements on a micro-roughness standard have been carried out between the LR-SFM and a stylus profiler. The obtained roughness values from both instruments are in excellent agreement with each other. This LR-SFM overcomes the difficulty that roughness values measured by conventional SFMs cannot be compared to stylus profilers or interference microscopes, mainly due to the fact that conventional SFMs do not have the required scanning range of ISO standardized evaluation methods.

Determination of the geometry of microhardness indenters with a scanning force microscope

Abstract: In this paper, experience gathered during the measurement of the geometry of microhardness indenters using a scanning force microscope is discussed. Reasonable accuracy of the geometrical parameters of a microhardness indenter can be obtained only if the scanning force microscope has been calibrated. The effect of the geometrical deviations on the result measured for the universal hardness is discussed.

Design of a Large Range XY Nanopositioning System

Abstract: Achieving large motion range (> 1 mm) along with nanometric motion quality (< 10 nm), simultaneously, has been a key challenge in nanopositioning systems. Practical limitations associated with the individual physical components (flexure bearing, actuators, and sensors) and their integration, particularly in the case of multi-axis systems, have restricted the range of current nanopositioning systems to about 100 μm. This paper presents a novel physical system layout, with a parallel-kinematic XY flexure mechanism at its heart, that provides a high degree of decoupling between the two motion axes by avoiding geometric over-constraints, provides actuator isolation that allows the use of large-stroke single-axis actuators, and enables a complementary end-point sensing scheme that employs commonly available sensors. These attributes help achieve an unprecedented 10 mm × 10 mm motion range in the proposed nanopositioning system. Having overcome the physical system design challenges, a dynamic model of proposed nanopositioning system is created and verified via system identification methods. In particular, dynamic non-linearities associated with the large displacements of the flexure mechanism and resulting controls challenges are identified. The physical system is fabricated, assembled, and tested to validate its simultaneous large range and nanometric motion capabilities. Preliminary closed-loop test results, which highlight the potential of this new design configuration, are presented.Copyright © 2010 by ASME

Accurate and traceable calibration of two-dimensional gratings

Abstract: Accurate and traceable calibration of lateral standards (1D and 2D gratings) is a basic metrological task for nano- and microtechnology. Both the mean pitch and the uniformity of the gratings should be measured quantitatively. Although optical diffractometers are effective for measuring the mean pitch, they are not able to measure the uniformity of gratings. In this study, the calibration of gratings is performed using a metrological large range scanning probe microscope with optimized measurement strategies. Two different kinds of data evaluation methods, a gravity centre method and a Fourier transform method, have been developed and investigated. Cosine error, a significant error source of the measurement, is analysed and corrected. Calibrations on several 1D gratings have been carried out. The calibrated mean pitch values have an excellent agreement with those measured by optical diffractometry. Nevertheless, irregularities of the gratings were only deduced from the SPM results. Finally, the usage of the 1D/2D gratings for the calibration of a typical SPM is illustrated.