During the past decade, piezo-resistive cantilever type silicon microprobes for high-speed roughness measurements inside high-aspect-ratio microstructures, like injection nozzles or critical gas nozzles have been developed. This article summarizes their metrological properties for fast roughness and shape measurements including noise, damping, tip form, tip wear, and probing forces and presents the first results on the measurement of mechanical surface parameters. Due to the small mass of the cantilever microprobes, roughness measurements at very high traverse speeds up to 15 mm/s are possible. At these high scanning speeds, considerable wear of the integrated silicon tips was observed in the past. In this paper, a new tip-testing artefact with rectangular grooves of different width was used to measure this wear and to measure the tip shape, which is needed for morphological filtering of the measured profiles and, thus, for accurate form measurements. To reduce tip wear, the integrated silicon tips were replaced by low-wear spherical diamond tips of a 2 µm radius. Currently, a compact microprobe device with an integrated feed-unit is being developed for high-speed roughness measurements on manufacturing machines. First measurements on sinusoidal artefacts were carried out successfully. Moreover, the first measurements of the elastic modulus of a polymer surface applying the contact resonance measurement principle are presented, which indicates the high potential of these microprobes for simultaneous high-speed roughness and mechanical parameter measurements.

Cantilever-type silicon microprobes with an integrated tip and a piezoresistive signal read out have successfully proven to bridge the gap between scanning force microscopy and stylus profilometry. Roughness measurements in high-aspect-ratio microstructures (HARMS) with depths down to 5 mm and widths down to 50 µm have been demonstrated. To improve the scanning speed up to 15 mm s−1, the wear of the tip has to be reduced. The atomic layer deposition (ALD) technique with alumina (Al2O3) has been tested for this purpose. Repeated wear measurements with coated and uncoated microprobe cantilevers have been carried out on a roughness standard at a speed of 15 mm s−1. The tip shape and the wear have been measured using a new probing tip reference standard containing rectangular silicon grooves with widths from 0.3 µm to 3 µm. The penetration depth of the microprobe allows one to measure the wear of the tip as well as the tip width and the opening angle of the tip. The roughness parameters obtained on the roughness standard during wear experiments agree well with the reference values measured with a calibrated stylus instrument, nevertheless a small amount of wear still is observable. Further research is necessary in order to obtain wear resistant microprobe tips for non-destructive inspection of microstructures in industry and microform measurements, for example in injection nozzles.

has been significantly improved and used to measure the stiffness of a cantilever. The facility is based on a disc pendulum with electrostatic reduction of its deflection and stiffness. In this paper, we will demonstrate that the facility is able to measure horizontal forces in the range below 1 μN with a resolution below 5 pN and an uncertainty below 2.7% for a measured force of 1 nN at a measurement duration of about 20 s. We will demonstrate the possibility of using this facility as a calibration device that can accurately determine spring constants of soft cantilevers (K < 0.1 N m −1 ) with traceability to the SI units. The method and the results of measuring the spring constant of a soft cantilever (K = 0.125 N m −1 ) in air, in a medium vacuum, in a high vacuum and in nitrogen are presented. We will show that a relative standard uncertainty of the spring constant calibration of better than 0.3% (measurement in a medium vacuum) and a repeatability of better than 0.04% are achieved.

Contact stylus-based surface profilometry is capable of topography measurement whilst being independent of the physical, electrical and optical properties of the materials under test, and has therefore become an indispensable tool for dimensional measurement of transparent specimens. However, large measurement deviations will appear when soft specimens, especially specimens made of polymers, are measured by contact stylus profilometry. In this paper the surface deformation behaviour of two polymers for molding and one photoresist, i.e. Ormocomp, Ormoclad and SU-8, under different tactile measurement conditions have been experimentally investigated. An empirical analytical model is hereby proposed for the prediction of surface deformation of soft specimens under tactile (sliding) contact. Preliminary experimental results demonstrate that the proposed five-parameter model is applicable for describing the deformation behaviour of these thermoplastic materials under the scanning speed ranging from 2 to 200 μm s−1 and the probing force varying from 5 to 500 μN. In addition, thanks to quantitative topographical measurements of the layer thickness of the aforementioned photoresists, the scratch behaviour and the time-dependent mechanical properties of these materials have also been experimentally determined.

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