Stability Observations and Surface Analysis of Air Fired Nickel Thick Film Conductors

The results from an investigation of the properties of air fired Nickel thick film produced with conductive paste ESL 2554 on 96% Al2O3substrates are described. The analysis of the possible causes of instability of this thick film material has been done using the methods of surface analysis. The picture of the film surface structure obtained as a result of surface analysis shows a non-isotropic distribution of the metal and glass phase. For a firing peak temperature of 650℃ there is little nickel present at the film surface, and this could be the main cause of the high instability and low adhesion observed. To obtain a stable film the maximum firing peak temperature has been established at 580℃. This has been confirmed by comparing the surface analysis results from films prepared at 650℃ and 580℃ peak temperatures.The surface analysis of the substrate shows the presence of Silicon which may be considered as another possible cause of film instability.

Reliability Compliance Testing of Electronic Components for Consumer Electronics

In this paper the organisation of reliability compliance testing of electronic components in Poland is discussed. The aim of the testing is to find the reliability of the components to both producer and user and hence to establish reliability for the two parties. The system described is derived from standard methods and has two aims. These are:-1) To enable periodical checks of production to be made.2) To estimate the reliability level of the components produced.Sampling plans are constructed on the basis of Weibull distributions. Individual life tests are performed to compare the reliability levels with those in the specification, and also to enable data to be accumulated for calculation of average failure rates. These tests are supervised by the quality centre UNITRA-ELECTRON. The centre is then in a position to provide reliability data on electronic components for the designers and producers of electronic equipment.The system of reliability compliance testing given in the paper will be effective if the tests are performed frequently. The aim is also to achieve results in the shortest possible time. In order to achieve these aims accelerated life testing has been investigated.Applicability of techniques, including that of accelerated life testing, to the study of reliability of polyester capacitors is examined.

Optical Fibre Connectors for Harsh Environments

This paper describes the construction of a multiway Optical Fibre connector suitable for harsh environments, based on a ruggedised marine connector (Patt 608) shell, and employs expanded-beam principles. The connector utilises an array of sapphire sphere lenses force-fitted into a metal plate forming a flat mating surface with all the precision parts protected behind the lenses.

Reproducibility of Properties of SnOxThin Films Prepared by Reactive Sputtering

The preparation of tin dioxide films by low energy reactive sputtering of tin and tin-antimony (1-10% wt. Sb) in an oxygen – argon atmosphere is described. The dependences of oxygen content in the range from 0 to 50%, target compositions, substrate temperature of 300 K-573 K on minimum resistivity at satisfactory transmittance and on reproducibility are discussed. The correlation between the electrical and optical properties and the microstructure of the films is shown.

On Experimental Data of the TCR of TFRs and Their Relation to Theoretical Models of Conduction Mechanism

Any theory of electrical conduction in TFRs encounters mainly two problems: (i) explanation of the dependence of R□on properties of conducting component (volume fraction, grain size, resistivity), (ii) explanation of the temperature dependence of R□taking into account (i). In order to achieve this one has to fit some microscopic parameters to experimental R□-and TCR-values, and to check if they are reasonable or not. The aim of the following discussion is to show, that such a fitting by means of experimental TCR-values is not correct. This is due to the fact that TCR-behaviour, as is well known, is determined also by the dependence of resistivity on strain. But any theoretical model neglects strains, also those who are induced by thermal strains. By means of published experiments concerning the strain dependence of resistance, the magnitude is estimated by which the TCR-values have to be corrected for the described fit.

Electrochemical Migration in Thick-Film IC-S

The phenomenon of silver migration in conductor-insulator systems is well known, but it is less known that several other metals can exhibit migration. This paper tries to give a short summary of the phenomenon as applied to thick-film circuits.Tests have been made on different conductors used in thick-film circuits. The dendrites formed by electrochemical migration were examined by scanning electron microscope, and also by wavelength-dispersive analysis of the emitted x-rays. By obtaining secondary and back-scattered electron images, x-ray maps and profiles, it can be determined which components cause migration in the conductor in question.Photos are presented illustrating the results.Thermal Humidity Bias test was also performed in controlled environmental chambers in order to get a comparison between different thick film systems.

Examination of Thick-Films Using Modern Surface Analytical Techniques

Modern surface analytical methods/EMPA, AES, SIMS etc. were used for studying the different layers in thick-film integrated circuits. Diffusion and migration effects, surface impurity distributions and surface compositions were examined. Some of the results are presented in this paper. Electrical measurements are not discussed here; only examples of the practical use of the methods are demonstrated.

Usage of Sims and Auger Test Methods in the Production of Multilayer Printed Circuit Boards

The quality and reliability of multilayer boards are determined by the adhesion strength between the copper sheets and the epoxy-glass laminates. The adhesion properties of copper foil may be improved by mechanical or chemical roughening. The most efficient method is, however, to oxidize the copper surface.Oxidized copper layers have been tested by thermogravimetry. Subsequently the oxide layers have been tested by Auger and SIMS techniques. The results showed that the main constituent of the oxide layer produced in a sodium hypochlorite type electrolyte is Cu20.