Investigation of the three-dimensional microstructure of Cu-Sn(Pb) diffusion zones by means of ion beam sputtering, scanning electron microscopy and lattice source interferences

On model substances of Cu-Sn(Pb) solders it is shown by the combined use of several physical analytical methods that the intermetallic compounds formed during the annealing process have a crystalline structure, which can be observed also three-dimensionally by ion etching. Moreover, grain boundaries as well as phases become visible, and it is possible to determine the crystallographic orientation of the individual crystals in the Cu starting material and in the diffusion zones by means of the Kossel technique. As a result of the investigations, conclusions can be drawn with respect to the diffusion process, especially also to the crystallographic structure of the diffusion zones and the dendritic growth.Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday     

Characterization of Cu-Sn/Pb diffusion zones of microelectronic contacts by means of electron probe microanalysis and ion beam sputtering

Physical parameters of material, such as strength and electrical conductivity, can be influenced considerably by the intermetallic compounds formed by diffusion in soldered microelectronic contacts between Cu and Sn/Pb solders. Therefore, formation and growth of these contact zones were systematically investigated on model specimens in dependence on temperature, time and chemical tin-lead concentration of the solders by means of electron probe microanalytical investigations and characterized by phase growth constants. Compared with the conventional metallographic specimen preparation method, the ion beam etching of the contact surfaces proves to be an excellently suitable means for representing the microstructure after the cooling of the samples. Moreover, the three-dimensional grain structure and technologically caused defects in the contact can be shown by ion beam slope cutting. Effects as e.g. the dendritic growth and Kirkendall pores which increasingly occur at higher temperatures are successfully proved.     

Estimation of cysteine and cystine at mercury pool electrode

Zusammenfassung Zum Ausgleich der starken Sogdifferenzen bei Wasserstrahlpumpen als Folge erheblich schwankender Wasserdrucke wird eine automatisch arbeitende Unterdruckregulierung beschrieben. Der dadurch erzielte konstante Nutzsog kommt im Laboratorium all den, Versuchsanordnungen zugute, die einen konstanten Unterdruck benötigen.