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Sensors have gained a wide theoretical interest and practical application in biomedicine. They can be used for very different purposes and may offer unique possibilities. The paper gives a broad summary about the biomedical sensor application fields and about their technologies. Finally, the present status and perspectives are summarised.

The purpose of this paper is to present a novel approach on investigating critical current densities in the solder joints of chip-size surface mounted device (SMD) components. The investigation involves a numerical approach and a physical validation with selected track-to-pad connections and high current loads (CXs).

During the investigations, shape of solder fillets was calculated in Surface Evolver, and then the current densities were calculated accordingly in the given geometry. For the verification, CX tests were performed on joints at elevated temperatures. The joints were qualified with X-ray microscopy, cross-section analysis and shear tests.

This study ascertained that the inhomogeneity in current density depends on the track-to-pad structure of the joint. Also this study found that the heavy CX decreases the mechanical strength, but the degradation does not reach the level of electromigration (EM)-induced voiding.

The heavy CX significantly affects joint reliability and the results point out to EM-induced failure-limitations on printed circuit board (PCB)-based assemblies due to the thermomechanical weakness of the FR4 material.

The experiments investigate current density from a novel aspect on more frequently used small-scale components with different track-to-pad configurations – pointing out possible failure sources.

The purpose of the paper is to improve the control of vapour phase soldering (VPS). To enable better productivity and assembling quality, the industry needs to provide precise control and measurements during assembling. In the paper, a special monitoring method is presented for VPS to enable improved process control and oven state identification.

The work presents the investigation of the workspace with dynamic and gage type pressure sensors in fusion with thermocouples. Different sensors were evaluated to find an appropriate type. The relation between the temperature and the pressure was investigated, according to the setup of the oven. The effect of inserting a printed circuit board (PCB) on the pressure of the vapour inside the oven was also investigated with the pressure/power functions.

It was found that the novel gage-type sensors enable better precision than solutions seen in previous literature. The sensors are able to monitor the decreasing vapour concentration when a PCB is inserted to the workspace. It was found that there is a suggested minimum power to sustain a well-developed vapour column for soldering in saturated vapour. An inflexion point highlights this in the pressure/power function, in accordance with the temperature/power curve.

The research presents original works with aspects of a novel sensor fusion concept and work space monitoring for better process control and improved soldering quality.

This paper aims to present a review of the recent developments in vapour phase soldering (VPS) technology. This study focuses on the following topics: recent developments of the technology, i.e. soft and vacuum VPS; measurement and characterization methods of vapour space, i.e. temperature and pressure; numerical simulation of the VPS soldering process, i.e. condensate layer and solder joint formation; and quality and reliability studies of the solder joints prepared by VPS, i.e. void content and microstructure of the solder joints.

This study was written according to the results of a wide literature review about the substantial previous works in the past decade and according to the authors’ own results.

Up to now, a part of the electronics industry believes that the reflow soldering with VPS method is a significant alternative of convection and infrared technologies. The summarized results of the field in this study support this idea.

This literature review provides engineers and researchers with understanding of the limitations and application possibilities of the VPS technology and the current challenges in soldering technology.

This paper summarizes the most important advantages and disadvantages of VPS technology compared to the other reflow soldering methods, as well as points out the necessary further developments and possible research directions.

To improve productivity and reach better quality in assembling, measurements and proper process controlling are a necessary factor. This study aims to focus on the monitoring heat-level-based vapour phase reflow soldering (VPS), where – as it was found – different thermocouple constructions can affect the set parameters of the oven and resulting soldering profiles significantly.

The study experiments showed significant alteration of the heating profiles during the process of the reflowing using different construction of k-type thermocouples. In a heat-level-based VPS oven, polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA) gas and water-resistant, fibreglass, thin PFA and ultrathin PFA-covered thermocouples were tested with ±1 °C precision. The oven parameters were swept according to the heating power; the length of the introduced thermocouple cables was also taken into account. An FR4-based sample PCB was used for monitoring the temperature.

According to the results, due to the mass and volume of the thermocouples’ wires, different transients were observed on the resulting soldering profiles on the same sample PCB. The thermocouples with lower thermal mass result in faster profiles and significantly different heating factor values compared to the thermocouples that have larger thermal mass. Consequently, the length of the thermocouple wires put in the oven has also considerable effect on the heat transfer of the PCB inside the oven as well.

The paper shows that the thermocouple construction must be taken into account when setting up a required soldering profile, while the thermal mass of the wires might cause a significant difference in the prediction of the actual and expected soldering temperatures.

This paper aims to present a novel approach on investigating critical current densities in the solder joints of chip-size surface-mounted components or device (SMD) components and ball grid array (BGA) lead-free solder joints with the focus of via-in-pad geometries. The investigation involves a numerical approach and a physical validation with selected geometry configurations and high current loads to reveal possible failure sources. The work is a continuation of a previous study.

Current density was investigated using finite element modeling on BGA joints. Dummy BGA components, 0402 and 0603 zero ohm jumper resistors, were used, both in daisy chain setups on standard FR4 printed circuit boards (PCBs). Respective physical loading experiments were set to find effects of elevated current density at hot zones of the joints. Cross-section analysis, scanning electron microscopy and shear force tests were used to analyze the joints.

The findings reveal alterations in the joints, while the current loading is not directly affecting the structure. The modeling reveals the current density map in the selected formations with increased current crowding zones. Overall, the degradation does not reach the level of electromigration (EM)-induced voiding due to the limiting factor of the FR4 substrate.

The heavy current load affects joint reliability, but there are limitations of EM-induced failures on PCB-based assemblies due to the thermomechanical weakness of the FR4 material.

The experiments investigate current density from a novel aspect on frequently used BGA surface mounted components with modeling configurations focusing on possible effects of via-in-pad structure.

Polymeric materials have gained a wide theoretical interest and practical application in sensor technology. They can be used for very different purposes and may offer unique possibilities. The paper gives a broad summary about the sensor structures and sensing polymer films used in a wide variety of sensors. Finally, the present status and perspectives as well as the advantages of specific polymer based sensors are summarised.

Two members of ISHM‐Hungary, Professor Zsolt Illyefalvi‐Vitéz, ELC representative, and Professor Gábor Harsányi, president and TPC representative, attended the NATO Advanced Research Workshop on MCM‐C/Mixed Technologies in Florida, USA, in May co‐sponsored by ISHM‐US and organised by:

‘Soldering and Cleaning in Electronics’ international conference, including an exposition, took place in Brno on 12–13 October 1993. The conference was organised by SMT‐Info, together with the ISHM‐Czech and Slovak Chapter. The purpose of this common action was to bring together the professionals in surface mount technology and thick film technology. In the framework of the conference, in which 130 home and foreign delegates participated, the annual meeting of the ISHM‐Czech and Slovak Chapter took place.