Ralph Schacht

Brandenburg University of Technology Cottbus - Senftenberg | BTU · Institute of Electrical Systems - Internet of Things

Pulsed Infrared Thermography (PIRT) is a very fast and non-destructive technique for testing various types of specimens. This makes PIRT interesting for inspections in industrial production lines. Especially for the die attach interface inspection of sintered and soldered electronic components and layer to layer interfaces in fiber-reinforced plast...

Additive manufacturing by laser cladding is a promising tool for rapid prototyping, construction of bionic structures and replacement part production. To ensure a constant quality of manufactured components and to shorten the development process between CAD model and suitable produced components quality management and process monitoring system is i...

This research focuses on the structural analysis of aircraft electrical harnesses for the 270 VDC network. A combined experimental and simulation-based approach is used, where numerical models for the harnesses are developed and experimental data are acquired for basic test cases (steady load, pendulum test, etc.) as well as for different vibration...

This paper deals with the development of an innovative test stand for the measurement of thermal and electrical conductivity of metals, semiconductors, highly conductive die attaches and substrates using the steady state technique for thermal characterization and four-terminal sensing with pulse delta technique for electrical characterization. We p...

This paper resumes the frictionless fan concept which was introduced at itherm 2012 [1]. This concept was based on a flexible polymer blade, the vibration of which is, as opposite to the piezoelectric driven fan principle, driven by means of a magnetic field. This type of fan can be of interest in regions where otherwise the fluid flow would be sta...

A frictionless air mover concept is introduced in this paper. As opposed to a piezoelectric driven fan, the air mover is based on a flexible blade whose vibration is driven by means of a magnetic field. The blade is based on a polymer material. The paper presents the results of a feasibility analysis and an on-going comprehensive design study. The...

The steady state method is a commonly used and in principle simple way to measure thermal resistance and conductivity of thermal interface materials (TIMs). The sample must be positioned between a hot and a cold plate with constant temperatures, whereby a heat flow through the sample and temperature gradient across the sample are generated. To dete...

The steady state method is a commonly used and in principle simple way to measure thermal resistance and conductivity of thermal interface materials (TIMs). A heat flow through the TIM has to be generated and the temperature gradient across the TIM has to be measured. This is also defined by the ASTM standard ASTM D5470 [4]. To generate the heat fl...

Commonly computational methods are used to determine and enhance the lifetime of electronics and electronic systems. The validity of such methods highly depends on the used material data and therefore on the quality of the accompanying experiments. For this reason different methods were combined to better determine the thermal state of a desired de...

This paper deals with the development und fabrication of a thermal test chip (TTC) to be used for thermal characterisation and qualification of materials and packages. The TTC is designed as a modular chip with the smallest full functional chip cell of 3.2mm × 3.2mm and consists of a heater structure and a temperature sensor. The chips can be appli...

A parametric transient thermo-electrical coupled PSPICE macro model for a power cable as well as the verification results of the experimental and finite element simulation will be introduced. The paper describes the modeling and simulation of a simplified, single-core cable parametric model, for the use in a circuit simulator e.g. PSPICE. The verif...

New packaging technologies are necessary to meet the demand for smaller and more reliable electronic devices. The so-called system-in-package (SiP) concept brings different technologies, material combinations and processes together in one package. To ensure the reliability of such a package reliable, fast and non-destructive failure analysis are ne...

New packaging technologies are necessary to meet the demand for smaller and more reliable electronic devices. The so-called system-in-package (SiP) concept brings different technologies, material combinations and processes together in one package. To ensure the reliability of such a package reliable, fast and non-destructive failure analysis are ne...

This paper deals with the system design, technology and test of a novel concept of integrating Si and SiC power dies along with thermo-electric coolers in order to thermally manage transients occurring during operation, thus turning it into a smart power device. The concept features double-sided cooling as well as new materials and joining technolo...

This paper introduces a miniaturized frictionless fan concept, which is similar to a piezo-electric driven fan principle. This type of fan has been employed for the enhancement of heat transfer by increasing the fluid circulation in regions which are otherwise stagnant. The introduced fan is based on a flexible blade whose vibration is driven by me...

http://www.leibniz-institut.de/ns2012/abo_ras_thermal_interface_characterization_micro-nano.pdf

New packaging technologies are necessary to meet the demand for smaller and more reliable electronic devices. The so-called system-in-package (SiP) concept brings different technologies, material combinations and processes together in one package. To ensure the reliability of such a package reliable, fast and non-destructive failure analysis are ne...

This paper introduces a miniaturized frictionless fan concept, which is similar to a piezo-electric driven fan principle and that can fits into a size of a matchbox. This type of fan has been employed for the enhancement of heat transfer by increasing the fluid circulation in regions which are otherwise stagnant. The introduced fan is based on a fl...

Thermal interface materials (TIMs) are widely needed to improve thermal contacts for facilitation heat transfer in electronic packaging, such as that associated with the flow of heat from microprocessor to a heat spreader or a heat sink in a computer. Due to thermal mismatch between these components mechanical strain occur which cause pump-out, cra...

Thermal interface materials (TIMs) are widely needed to improve thermal contacts for facilitation heat transfer in electronic packaging, such as that associated with the flow of heat from microprocessor to a heat spreader or a heat sink in a computer. Due to thermal mismatch between these components mechanical strain occur which cause pump-out, cra...

Designers of electronic packages and electronic circuits require thermal optimization for electrical and thermal plated through holes (PTH) respectively to obtain a reliability estimate. Reliability depends on PTH-geometry and manufacturing process conditions which influence thermo-mechanical properties of the board (viscous-elasticity) and electro...

The ongoing need for miniaturization and speed in electronics industry has brought a requirement for better performing thermal management systems. One of the major bottlenecks in thermal management is the thermal interface resistance. Characterisation of thermal interface materials become even tougher a challenge at low bond line thicknesses and hi...

As the demand for new thermal technologies and materials has been increasing over the years to provide thermal solutions to the next generation of power electronics, microprocessors and high-power optical systems also thermal characterisation methods have to keep up with the pace of this development with respect to resolution and accuracy. We have...

Nowadays very often IR-thermography is used to analyze the temperature on electronic device surfaces. To measure the absolute surface temperature correctly, the IR-camera detector has to be calibrated with a corresponding evaluation software using a black body calibration device. Commercially available black radiators are heavyweight and a calibrat...

Nowadays very often IR-thermography is used to analyze the temperature on electronic device surfaces. To measure the absolute surface temperature correctly, the IR-camera detector has to be calibrated with an corresponding evaluation software using a black body calibration device. Commercially available black radiators are heavyweight and a calibra...

As the demand for new thermal technologies and materials has been increasing over the years to provide thermal solutions to the next generation of power electronics, microprocessors and high-power optical systems also thermal characterisation methods have to keep up with the pace of this development with respect to resolution and accuracy. Within t...

In this paper we examine the thermo-mechanical reliability of polymer-encapsulated chip-on-board (COB) assemblies for power applications by simulation and experiment. Thereby the focus is set on the low cycle fatigue failure behaviour of the die-attach material under thermal cycling conditions. As die-attach material different solder materials and...

Taking the advantage of the thermo-elastic effect, while using an infrared camera system, the mechanical stress could be made visible. The stress concentrations at the tip of a subcritical crack growth could clearly be detected. Through the observation during the periodic loading of a CT-specimen the crack growth rate can be determined. For this pu...

IR-thermography has become increasingly important for non-destructive testing of microelectronic devices and structures on chip, package and board-level. This paper focuses on the evaluation of best applicability for different pulse excitation modes to detect flaws and damages as well as to determine material properties. Pulse IR thermography using...

Thermal characterisation of thermal interfaces becomes even tougher a challenge at low bond line thicknesses and higher thermal conductivities of the interface materials as more accurate measurement techniques are required. As in parallel the quest for high conductivity adhesives and greases is ongoing, a correlation between thermal bulk or interfa...

This paper derives and evaluates an effective thermal material simulation model in simula-tion and experiment as well as proposes a non-destructive failure analysis for multi-layer sub-strates with thermal or electrical vias to derive exact failure data to supplement existing life-time models. The effective thermal material simulation model is inve...

This paper proposes a new effective thermal material simulation model as well as a non-destructive failure analysis for multi-layer substrates with thermal vias to derive exact failure data to supplement existing lifetime models. An effective thermal material simulation model is derived which is validated in simulation and experiment in transient m...

Prime concerns in designing liquid cooling solutions are performance, reliability and price. To that end a one-phase liquid cooling concept is proposed, where all pumps, valves and piping are fully integrated on board level. Only low-cost organic board technology and SMT processes are used in the design. This paper addresses the key issues of such...

The use of multi-layer ceramic chip capacitors as integrated passive in e. g. system in package applications needs methods to examine and predict their reliability. Therefore, a nondestructive failure analytical technique is described to detect cracks in the ceramic and the metallic layers within encapsulated 0402 SMD capacitors. After choosing fro...

In this paper new characterization equipment for thermal interface materials is presented. Thermal management of electronic products relies on the effec-tive dissipation of heat. This can be achieved by the optimization of the system design with the help of simulation methods. The precision of these models relies also on the used material data. For...

Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/5920)

In this paper new characterization equipment for thermal interface materials is presented. Thermal management of electronic products relies on the effective dissipation of heat. This can be achieved by the optimization of the system design with the help of simulation methods. The precision of these models relies also on the used material data. For...

Thermisches Management von elektronischen Produkten baut auf eine effektive Wärmeabfuhr unter den gegebenen Randbedingungen und Möglichkeiten auf. Zur schnellen und effizienten Umsetzung der thermischen Systemoptimierung während der Entwurfsphase stehen hierfür verschiedene Simulationsmethoden zur Verfügung. Die Genauigkeit der thermischen Simulati...

In this paper reliability test equipment is presented that allows accelerated failure tests of packaged power MOSFETs (e.g. TO220, TO263). The failure criterion used is an increase in thermal impedance which is observed in-situ during testing. The duration of the cycles depends on the shift of the junction temperature T_J: Testing with a...

It is necessary to improve the lifetime prediction based on FE-methods of different electronic packages in order to reduce the time and costs of new developments. This paper purposes a method describing the crack propagation of chip on copper substrate solder joints. The chips that were studied are power transistors. They were soldered on copper su...

In the paper we present an approach based on this principle to design reliable thermal management solutions for high power applications. Thermal and thermo-mechanical reliability are measured and calculated for a flip-chip mounted die with a hot-spot using reverse-side micro-channel water cooling as cooling concept. Hereby the methodology starts by...

In information and communication technology, the future has already begun. The transfer of vast amounts of data is routinely done via the Internet, and mobile or portable multiple-use devices or workstations ensure that the information we require is at ready hand, anywhere and at any time. System integration technologies and the Internet as a user...

For optimum design of electronics cooling solutions thermal performance and thermo-mechanical reliability have to be addressed right from the beginning and on an equal footing. This entails a comprehensive approach: Virtual prototyping by FE-simulations as well as experimental verification and testing focused a priori on materials, technology and f...

In der vorliegenden Arbeit wird eine Methode vorgestellt, welche die Beschreibung und Si-mulation von thermo-elektrischen Kopplungen während des Design-Prozesses mittels Mak-romodellierung unterstützt. Das Makromodell ist für den Einsatz in dem Schaltungssimulator PSpice zugeschnitten. Es ermöglicht die rechenzeiteffiziente transiente Simulation zw...

1. Introduction Ambient temperature, Joule heating by current through the LED and the current itself (electron scattering) are the main reasons for degradation of an LED [1]. In the inner region the cause of degradation can be dislocation or precipitation. Point, line and plane defects can be formed and typically result in a higher current leakage...

Pulse IR thermography has been used for the detection of hidden flaws and cracks in macroscopic structures (e.g. turbine blades, propellers) for several years, but as IR cameras are becoming increasingly refined in their time, space and temperature resolution capabilities it is possible to transfer the method on to failure detection in microelectro...

High integrated electronic PCB boards for high power applications needs new cooling Concepts. The 3D-Packaging technology makes it possible to stack PCBs on top of each other and thus make full use of the third dimension. The new SMT compatible Technology will be demonstrated on an 3D-PCB-Package in 11 PCB-layer with water cooled high power compone...

Für die zerstörungsfreie Untersuchung von elektrischen und thermischen Durchkontaktierungen in Leiterplatten zur Entwicklung eines präziseren Lebensdauermodells für die Zuverlässigkeitsabschätzung wurde der Einsatz der Wärmeflussthermographie mittels elektrischer und Laseranregung untersucht. Die Ergebnisse zeigen, dass mittels FE-Simulationskorre...