Austria Technology and Systemtechnik AG

Leoben, Austria

Austria Technology and Systemtechnik AG

Leoben, Austria
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Tao Q.,University of Leoben | Tao Q.,Austria Technology and Systemtechnik AG | Pinter G.,University of Leoben | Krivec T.,Austria Technology and Systemtechnik AG
Microelectronics Reliability | Year: 2017

Glass transition temperature (Tg) is a key epoxy property and often being monitored in the production by the differential scanning calorimeter (DSC) method in the printed circuit board (PCB) industry. The dual-effect of cooling rate and annealing on the endothermic peak in the DSC scan of CE-688 epoxy resin plays a big role in the DSC Tg evaluation. An improved DSC program was developed in order to minimize/eliminate the influence of endothermic peak. Meanwhile, the curing pressure also shows distinct effect on the Tg of the epoxy resin. © 2017.


Fuchs P.F.,Polymer Competence Center Leoben | Pinter G.,University of Leoben | Krivec T.,Austria Technology and Systemtechnik AG
2014 15th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2014 | Year: 2014

In this work a method was worked on that assesses the lifetime of printed circuit boards (PCBs) under low cycle fatigue conditions. The method was based on finite element models and low cycle fatigue experiments. Verifying it, two significantly different PCB designs and several different PCB built ups were analyzed. Doing so, for the numerical part the individual layer materials were characterized, material models were defined and simulation models were built. A submodelling technique had to be applied in order to evaluate the local loading situation. For the experimental part corresponding PCBs were manufactured and a statistically relevant number of boards were tested in a board level cyclic bend test (BLCBT) while the critical connections were monitored. Based on the results of one PCB a correlation model describing the dependence of the cycles to failure on the local loading situation was formulated and used for the lifetime assessment of the other boards. A very good agreement between predicted and measured results could be shown. © 2014 IEEE.


Langer G.,Austria Technology and Systemtechnik AG | Leitgeb M.,Austria Technology and Systemtechnik AG | Nicolics J.,Vienna University of Technology | Unger M.,Vienna University of Technology | And 2 more authors.
SMT Surface Mount Technology Magazine | Year: 2014

With increasing power loss of electrical components, the thermal performance of an assembled device becomes one of the most important quality factors in electronic packaging. Due to the rapid advances in semiconductor technology, particularly in the realm of high-power components, the temperature dependence of long-term reliability is a critical parameter and has to be considered with the highest possible care during the design phase.


Wenzl F.P.,Joanneum Research | Sommer C.,Joanneum Research | Hartmann P.,Joanneum Research | Pachler P.,Tridonic Jennersdorf GmbH | And 4 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

Color constancy and color maintenance are key issues in the context of the utilization of light-emitting diodes (LEDs) for general lighting applications. For a systematic approach to improve the white light quality of phosphor converted LEDs and to fulfill the demands for color temperature reproducibility and constancy, it is imperative to understand how compositional, optical and thermal properties of the color conversion elements (CCE), which typically consist of a phosphor particles embedded in a transparent matrix material, affect the correlated color temperature of a white LED source. Based on a combined optical and thermal simulation procedure, in this contribution we give a comprehensive discussion on the underlying coherences of light absorption, quantum efficiency and thermal conductivity and deduce some strategies to minimize the temperature increase within the CCE in order to maintain acceptable color variations upon device operation. © 2012 SPIE.


Krivic P.,Vienna University of Technology | Wenzl F.-P.,Joanneum Research | Sommer C.,Joanneum Research | Langer G.,Austria Technology and Systemtechnik AG | And 4 more authors.
Proceedings of the International Spring Seminar on Electronics Technology | Year: 2012

The reliability and long-term stability of solid-state lighting devices strongly depend on successful thermal management. It is well known that junction temperature instability negatively impacts the lightning properties of LED illuminators. However, for prediction of life time and longterm stability the temperature distribution also inside the color converter must be known. A deeper understanding of these demanding thermal issues is provided in our paper on the base of measurements and simulations also taking into account the spatial power loss distribution due to absorption of light and Stokes shift within the color converter. For this purpose 3-dimensional models were set-up and examined to thermally characterize high-power LED assemblies. Two different types of set-ups were investigated. Moreover, an efficient solution is presented where a junction-to-case thermal resistance below 10 K/W is achieved. © 2012 IEEE.


Langer G.,Austria Technology and Systemtechnik AG | Leitgeb M.,Austria Technology and Systemtechnik AG | Nicolics J.,Vienna University of Technology | Unger M.,Vienna University of Technology | And 2 more authors.
IPC APEX EXPO 2014 | Year: 2014

With increasing power loss of electrical components, thermal performance of an assembled device becomes one of the most important quality factors in electronic packaging. Due to the rapid advances in semiconductor technology, particularly in the regime of high-power components, the temperature dependence of the long-term reliability is a critical parameter and has to be considered with highest possible care during the design phase. Two main drivers in the electronics industry are miniaturization and reliability. Whereas there is a continuous improvement concerning miniaturization of conductor tracks (lines / spaces have been reduced continuously over the past years), miniaturization of the circuit carrier itself, however, has mostly been limited to decreased layer-counts and base material thicknesses. This can lead to significant component temperature and therewith to accelerated system degradation. Enhancement of the system reliability is directly connected to an efficient thermal management on the PCB-level. There are several approaches, which can be used to address this issue: Optimization of the board-design, use of base materials with advanced thermal performance and use of innovative buildup concepts. The aim of this paper is to give a short overview about standard thermal solutions like thick copper, thermal vias, plugged vias or metal core based PCBs. Furthermore, attention will be turned on the development of copper filled thermal vias in thin board constructions. In another approach advanced thermal management solutions will be presented on the board level, exploring different buildup concepts (e.g. cavities). Advantages of cavity solutions in the board will be shown, which not only decrease the thermal path leading from the high power component through the board to the heat sink, but also have an impact concerning the mechanical miniaturization of the entire system (reduction of z-axis). Such buildups serve as packaging solution and show an increase in mechanical and thermal reliability. Moreover, thermal simulations will be conducted and presented in this paper in order to reduce production efforts and to offer optimized designs and board buildups.


Langer G.,Austria Technology and Systemtechnik AG | Satzinger V.,Joanneum Research | Schmidt V.,Joanneum Research | Schmid G.,Vienna University of Technology | Leeb W.R.,Vienna University of Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

The increasing demand for miniaturization and design flexibility of polymer optical waveguides integrated into electrical printed circuit boards (PCB) calls for new coupling and integration concepts. We report on a method that allows the coupling of optical waveguides to electro-optical components as well as the integration of an entire optical link into the PCB. The electro-optical devices such as lasers and photodiodes are assembled on the PCB and then embedded in an optically transparent material. A focused femtosecond laser beam stimulates a polymerization reaction based on a two-photon absorption effect in the optical material and locally increases the refractive index of the material. In this way waveguide cores can be realized and the embedded components can be connected optically. This approach does not only allow a precise alignment of the waveguide end faces to the components but also offers a truly 3-dimensional routing capability of the waveguides. Using this technology we were able to realize butt-coupling and mirror-coupling interface solutions in several demonstrators. We were also manufacturing demonstrator boards with fully integrated driver and preamplifier chips, which show very low power consumption of down to 10 mW for about 2.5 Gbit/s. Furthermore, demonstrators with interconnects at two different optical layers were realized.


Sommer C.,Joanneum Research | Fulmek P.,Vienna University of Technology | Nicolics J.,Vienna University of Technology | Schweitzer S.,Joanneum Research | And 7 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

For a systematic approach to improve the white light quality of phosphor converted light-emitting diodes (LEDs) for general lighting applications it is imperative to get the individual sources of error for correlated color temperature (CCT) reproducibility and maintenance under control. In this regard, it is of essential importance to understand how geometrical, optical and thermal properties of the color conversion elements (CCE), which typically consist of phosphor particles embedded in a transparent matrix material, affect the constancy of a desired CCT value. In this contribution we use an LED assembly consisting of an LED die mounted on a printed circuit board by chip-on-board technology and a CCE with a glob-top configuration on the top of it as a model system and discuss the impact of the CCE shape and size on CCT constancy with respect to substrate reflectivity and thermal load of the CCEs. From these studies, some general conclusions for improved glob-top design can be drawn. © 2013 SPIE.


Fulmek P.,Vienna University of Technology | Sommer C.,Joanneum Research | Hartmann P.,Joanneum Research | Pachler P.,Tridonic Jennersdorf GmbH | And 4 more authors.
Advanced Optical Materials | Year: 2013

For further improvements to the reliability and the white light quality of phosphor-converted light-emitting diodes (LEDs), it is imperative to understand how the compositional, optical, and thermal properties of the materials constituting the color-conversion elements (CCEs) affect their respective thermal loads. By means of a combined optical and thermal simulation procedure, a comprehensive discussion is given on the underlying coherences of the absorption profile of the blue LED light, the phosphor concentration, the quantum efficiency of the phosphor, and the thermal conductivities of the CCEs. Some general strategies of material composition and design are deduced in order to minimize the thermal load of the CCEs, which is a prerequisite for correlated color temperature maintenance and long-term material reliability of phosphor-converted white LEDs. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Wenzl F.P.,Joanneum Research | Sommer C.,Joanneum Research | Hartmann P.,Joanneum Research | Pachler P.,Tridonic Jennersdorf GmbH | And 4 more authors.
Optics Express | Year: 2013

For a systematic approach to improve the reliability and the white light quality of phosphor converted light-emitting diodes (LEDs) it is imperative to gain a better understanding of the individual parameters that affect color temperature constancy and maintenance. By means of a combined optical and thermal simulation procedure, in this contribution we give a comprehensive discussion on the impact of different current driving schemes on the thermal load of the color conversion elements (CCEs) of phosphor converted LEDs. We show that on the one hand a decreasing duty cycle under pulse width modulation driving conditions may cause a notable temperature variation and on the other hand also effects due to the non-linearity between the blue radiant flux and the current have to be considered for the thermal load of the CCEs. © 2013 Optical Society of America.

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