Key Engineering Materials Vols. 381-382

Abstract: A planar capacitive sensor (PCS) is proposed for X and Y directions measurement. One axial displacement can be measured without the coupling of another axial movement. Two groups electrodes with 90 degree out-of-phase, forming triangle sine and triangle cosine wave, can be applied for direction detection and interpolation, aiming at high resolution. Simulation results show that proposed PCS is available for planar measurement.

Abstract: This paper discusses the temperature characterization for nano-polishing of polycrystalline diamond composites (PCDCs) by combined experimental and theoretical modelling. It was found that a higher polishing pressure-speed combination results in a higher temperature rise and material removal rate. To optimize the nano-polishing of PCDCs and achieve a surface roughness of Ra = 50 nm, the interface temperature at polishing needs to be maintained at an appropriate level.

Abstract: This paper presents a study of effect of cutting conditions on surface quality in FTS machining of optical microstructures such as micro-lens array. A power spectrum analysis is proposed to characterize the surface quality in FTS machining. It is found that there is a strong relationship between the surface roughness and the power spectrum of the surface profile. This provides an important means for the characterization of surface quality in FTS machining of optical microstructures.

Abstract: In this paper, the influences of abrasive size, abrasive concentration and admixture way on the abrasive dispersing of the sintered ultra-fine diamond tool were systemically investigated. Then, a comparison of the abrasive dispersing was made between the sintered ultra-fine diamond tool and the newly developed ultra-fine diamond tool by gel technique. ESEM was applied to observe the abrasive dispersing of the sintered and gel-coupled ultra-fine diamond tools. The abrasive dispersing was quantitatively evaluated by the statistic laws of grit spacing in a certain area. Experimental results indicated that the dispersing was mainly influenced by the abrasive size. The ultra-fine abrasive tended to agglomerate with the decrease of grit sizes due to the increase of surface energies. The abrasive concentration and admixture way had few effects on abrasive dispersing. The abrasive dispersing of the sintered diamond tool was worse compared with the gel-coupled ultra-fine diamond tool.

Abstract: Silicon (100) substrates machined by chemo-mechanical-grinding (CMG) and chemicalmechanical- polishing (CMP) were investigated using atomic force microscopy, cross-sectional transmission electron microscopy and nanoindentation. It was found that the substrate surface after CMG was slightly better than machined by CMP in terms of roughness. The transmission electron microscopy analysis showed that the CMG-generated subsurface was defect-free, but the CMP specimen had a crystalline layer of about 4 nm in thickness on the top of the silicon lattice as evidenced by the extra diffraction spots. Nanoindentation results indicated that there exists a slight difference in mechanical properties between the CMG and CMP machined substrates.

Abstract: The paper presents metrology of the growth and characterization of 3d metal monolayer films on silicon. EELS analysis of plasmon peaks during the layer-by-layer growth of Co films on Si(111) demonstrate that thickness measurement of the monolayer films is possible on base of spectra decomposition with interface and film plasmon peak extracting. Results of the resistivity measurement of Co films on Si(111) with different state of the surface correlate with growth mechanism of the films on AES data. AFM-pictures show replication of step surface relief versus the thickness demonstrating growth of the smooth Fe nanofilm on Si(100).

Abstract: In this work we show that in many practical situations it is possible to obtain the dielectric constant of coatings on plane conductive substrates by means of capacitance measurements with a single electrode without precise knowledge of the thickness.

Abstract: We report the results of the broadband dielectric constant and loss tangent of the new complex perovskites Ba3MnTa2O9 with the test frequency f in different ranges from 1 kHz to 15 GHz. For the test frequency f below 1 MHz, the dielectric constant and loss tangent of the specimens were measured using a LCR meter with four-terminal configuration. The measurements at frequencies between 50 MHz and 1 GHz were performed by the lumped impedance method, which uses an impedance analyzer to measure the complex impedance of the specimen. At frequencies above 1 GHz, two samples with diameter 9 mm and different thicknesses (2.73 mm and 5.42 mm) were measured by a home-made Hakki-Coleman resonator. The TE011 resonant peaks were found and identified with an Agilent PNA net-work analyzer. The dielectric constants were found to remain almost constant with the test frequency at room temperature. The calculated values of the real part dielectric constants are 17.74 and 17.53 at 9.86 GHz and 15.43 GHz, respectively. The unloaded Q factors deduced from curve fitting of the peaks are both around 200.

Abstract: To overcome the limitations of conventional interferometry, a technique has been developed which allows the absolute topography measurement of near-plane and slightly curved optical surfaces of arbitrary size with low measurement uncertainty. The Extended Shear Angle Difference (ESAD) method combines deflectometric and shearing techniques in a unique way to minimize measurement errors and to optimize measurand traceability. A device for the topography measurement of optical surfaces up to 500 mm in diameter, achieving sub-nanometer repeatability, reproducibility and uncertainty, was built at the Physikalisch-Technische Bundesanstalt (PTB). The ESAD method is optimally suited for creating a primary standard for straightness and flatness with highest accuracy by which the three-flat test or liquid mirrors can be replaced as starting points of the traceability chain in flatness measurement. In the following, the improved ESAD device which uses optimized opto-mechanical components is presented. Central aspects of the proper design and use of deflectometric systems are highlighted, including the optimal use of pentaprisms.

Abstract: A movable pentaprism is a key element in deflectometric profilers, where it directs the beam of an angle measuring device towards the surface under test and enables at the same time the flexible lateral displacement of the beam footprint on the surface. The beam deflection angle of the pentaprism is robust with regard to changes in its angular orientation. Optimal stability is achieved, however, only when the angle measuring device, the pentaprism, and the surface have initially been properly aligned. A newly developed procedure enables the rapid and accurate in-situ adjustment of all angles of the optical components in deflectometric set-ups with an uncertainty of several microrad. In combination with precision mechanical stages, variations in the prism’s deflection angle (caused by changes in its angular orientation) can then be limited to the nanorad level.