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A new hybrid substrate technology for power electronic applications has been characterised by thermal resistance and mechanical stress measurements. The new substrate utilises thermal spray technology for deposition of dielectric layer and electrical conductors. The results are compared with the more established technology of alumina substrates with direct copper bonding (DCB) metallisation. Silicon test chips for thermal resistance and mechanical stress measurement were used for the characterisation. The experimental results were compared with finite element analysis and a reasonable agreement was found.

The paper gives design guidelines for polymer thick‐film technology (PTF). After an introduction reviewing the main PTF properties, materials and processes, detailed PTF design rules are presented. They are conservative, to achieve high production yield. The design rules are based on the considerable experience in the companies of the authors and of the persons mentioned in the acknowledgements, as well as on information from the open literature and from materials suppliers. The design guidelines are intended primarily for designers, but they are also important for production personnel, to facilitate a close coupling between design and production, and thus provide optimum use of PTF and obtain high production yield.

The Center for Industrial Research (SI), the University of Oslo (UiO) and a group of Norwegian companies have collaborated between 1990 and 1992 in the research programme ‘Industrial Microelectronics’ with a total cost of 30 MNOK. The programme was sponsored by the Norwegian Scientific and Industrial Research Council (NTNF) as one of the twin programmes constituting a national research initiative in microelectronics. The motivation for the programme is the recognition of microelectronics as a key technology commanding the performance and market success of many of the electronics systems from the Norwegian electronics industry towards the year 2000. The main objective is to stimulate industrial innovation by developing, transferring and exploiting knowledge and methods based upon advanced microelectronics. Focused activities are silicon sensor technology, combined analogue/digital design of application‐specific integrated circuits, large scale instrumentation, sensor packaging and thermal management of electronic systems. SI is focusing on applied research, UiO on education, and collaborating Norwegian companies are using the results in their own R&D projects. It is anticipated that the research results will be fully industrialised within 3–5 years. The programme is co‐ordinated with other Norwegian government‐sponsored research activities as well as European research programmes based on microelectronics. The programme is organised in projects and monitored with a set of milestones strongly indicating the achievement of successful industrial innovation, research results of international standing and high‐quality education of key personnel for the industry. Several successful examples of the research results are highlighted: Design and process methodology for double‐sided microstrip silicon radiation sensors for detection of high energy elementary particles, silicon‐to‐silicon and silicon‐to‐thin film anodic bonding processes for sensor fabrication, combined analogue/digital application‐specific integrated circuits for front‐end instrumentation applications, packaging of radiation sensors and thermal management of electronic systems by evaporation cooling. It is concluded that the programme has successfully achieved results in harmony with the objective.

A theory for the thermal resistance in adhesive joints between semiconductor dice and substrates has been developed. The theory takes into account the thermomechanical shear stress in the bond layer caused by differences in thermal expansion. The theoretical result indicates that only small reductions in thermal resistance can be obtained by increasing the bulk thermal conductivity of the adhesive by filling it with silver particles. Experiments were carried out in order to verify this effect. An epoxy resin was loaded with various amounts of silver particles and used to bond thermal test chips to copper substrates. There was a surprisingly small difference in thermal resistance between the various adhesives. The difference was considerably less than the difference in bulk thermal conductivity indicated, thus confirming the basic result of the theory.

As announced in the May issue of Hybrid Circuits, ISHM‐Benelux is organising a one‐day conference on applications of hybrid circuit technology.

The solderability of a material is considered as the ability of the surface to be wetted by solder, and the rate at which this process occurs. The solderability of thick film conductors based on palladium—silver, by Pb/Sn/Ag solder, was evaluated using a meniscograph. The influence of the composition of the conductor and that of the temperature of the solderbath on the solderability were measured. The usefulness of meniscographic data for the production line is indicated by showing the relation between the production data, reported as the rate at which a full automated solder machine is operated, and the meniscographic results.

This one‐day seminar, repeated in Sweden and Denmark, had its origins in a most interesting co‐operative project which was supported in the four Nordic countries by a total of eleven companies and research organisations. A series of six projects, each relating to a particular aspect of Polymer Thick Film Technology, was agreed by the participants, and the work programme was carried out mainly in national research institutes but with a considerable input from industrial collaborators.

ISHM‐Benelux held its 1987 Autumn Conference on 29 October, at the Antwerp Crest Hotel. This one‐day meeting focused on applications of hybrid circuit technology in various fields of electronic and related industries.