The cleaning of silicon density standards was investigated by mass comparison measurements. It was shown that even in clean laboratory air, the mass of silicon spheres increases considerably with time. On the other hand, after cleaning the sphere, mass stabilizes within only 8 hours and always yields the same mass within 10 µg. This is also true after using the spheres in liquids, e. g., for hydrostatic weighing. Additionally, an infrared absorption technique was used to identify hydrocarbons on silicon spheres and to estimate the layer thickness. A calibration of this method was possible with a mass determination of a paraffine layer deposited on a silicon sphere.

Scatterometry is a non-imaging indirect optical method in wafer metrology to characterize periodic surface structures with dimensions in the micro- and nanometer range. It is also important to lithography masks designed for extreme ultraviolet lithography (EUVL), where light with wavelengths in the range of 13 nm is applied. The solution of the inverse problem, i.e. the determination of periodic surface structures with respect to their critical dimensions (CD) and other profile properties from light diffraction patterns, is incomplete without knowledge of the uncertainties associated with the reconstructed parameters. With decreasing feature sizes of lithography masks, increasing demands on metrology techniques and their uncertainties arise. The numerical simulation of the diffraction process for periodic 2D structures can be realized by the finite element solution of the two-dimensional Helmholtz equation. The inverse problem can be formulated as a non-linear operator equation. The operator maps the sought mask parameters to the efficiencies of diffracted plane wave modes. The operator equation can be solved by optimization, i.e., minimizing the deviation of the calculated efficiency or phase shift values from the measured ones. Clearly, the uncertainties of the reconstructed profile parameters essentially depend on the uncertainties of the input data and can be estimated by various methods. A Monte Carlo procedure and an approximate covariance method is applied to evaluate the reconstruction algorithm. Particularly, we analyze the impact of uncertainties in the model parameters by the Monte Carlo method. Reconstruction results and their uncertainties are presented for the measurements of typical EUV masks. They are composed of 140 nm wide TaN absorber lines of about 80 nm height, a period of 420 nm, and with an underlying MoSi-multilayer stack of 49 periods.

The article presents issues connected with coordinate measurements of spatial surfaces. These measurements are presented on the example of carrying out the reverse engineering process of objects described with the use of free surface patches. The introduction to the article comprises a presentation of the B-spline method. This method has been applied to constructing geometric models of the reconstructed surfaces. Moreover, the introduction presents a method of constructing a surface patch on the basis of a cloud of points in space. Further in the article, a practical implementation of the methodology of reconstructing objects described with the use of complex shape surface patches has been presented. The methodology includes subsequent object measurements and reconstructing the object's geometric model, and concentrates on the possibly most accurate reconstruction of the shapes and dimensions of the researched object. While performing the reverse engineering process, the issues connected with selecting the best measurement strategy adjusted to the class of the reconstructed object as well as to the assumed geometric modelling method are discussed.

There is a continuous pressure to increase quality of the passive elements at reduction of their production costs. Therefore, present methods of their quality assessment have to be reconsidered to avoid usage of the elements that could break down and lead to serious economical losses. This paper compares results of capacitor tests introduced by the obligatory technical standards and measurements of acoustic emission induced by partial discharges within voids in foil-based capacitors. We suppose that presence of voids within dielectric and foil structures can lead to capacitor damage and can not be detected by measurements of dielectric loss or capacitance only.

In this paper, a research activity aimed at developing an indoor positioning system is presented. The realized system prototype uses sensor fusion techniques to combine information from two sources: a local Ultra-Wideband (UWB) radio based distance-measuring system infrastructure and an Inertial Navigation System (INS). The UWB system provides a measure of distance between two transceivers by measuring the time-of-flight of pulses. Its principle of operation is briefly described, together with the main features of its architecture. Furthermore, the main characteristics of the INS and of the Extended Kalman Filter information fusion approach are presented. Finally, some experimental results are provided, relative to static and dynamic position measurements.