Mohamad Abo Ras

• Dr.-Ing.
• CEO at Berliner Nanotest und Design GmbH

The vision of a deep learning-empowered non-destructive evaluation technique aligns perfectly with the goal of zero-defect manufacturing, enabling manufacturers to detect and repair defects actively. However, the dearth of data in manufacturing is one of the biggest obstacles to realizing an intelligent defect detection system. This work presents a...

Graphical abstract to our paper titled "Synthetic data generation using finite element method to pre-train an image segmentation model for defect detection using infrared thermography". For more details, read the article (open access), the doi: https://doi.org/10.1007/s10845-024-02326-1

In this work, a Thermal Test Vehicle (TTV) is developed to demonstrate the thermal characterization utilities for large die area packages. The TTV consists of a silicon Thermal Test Chip (TTC) on organic interposer assembled with lid and thermally conductive adhesive as thermal interface material. The setup mimics the system-level application and t...

Electronic components of which reliability cannot be quantified are unacceptable and potentially hazardous, especially in safety-relevant areas such as driver assistance systems and medical technology where the zero-error principle applies. Reliability as a quality criterion has its origin in production, i.e. process variations have a negative infl...

The tilt of semiconductor dies is a common issue during assembly in power electronics as, e.g. die bonding during silver sintering caused by inhomogeneous thicknesses of applied die-attach material, problems with a homogeneous force application, uneven substrates etc. This tilt usually leads to reliability problems later during testing or operation...

In this study, we demonstrate the capabilities of lock-in thermography (LIT) for the inspection of sintered chip interconnections. The laser LIT technology is used to detect delamination in the sintered layer between copper pad and SiC chip. This work will present a LIT system for the failure analysis (FA) without spray coating for industrial inspe...

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...

Tilt of semiconductor dies is a common issue during assembly in power electronics as e.g., die bonding during silver sintering caused by inhomogeneous thicknesses of applied die-attach material, problems with a homogeneous force application, uneven substrates etc. This tilt usually leads to reliability problems later during testing or operation in...

This study shows a technique to avoid the necessary spray-coating of devices under test with low- emissivity surfaces in failure analyses by pulsed IR thermography. Such samples can be sintered or soldered electronic components. The mentioned technique is based on a vacuum foil lamination process, which does not contaminate the samples and saves th...

Die fortschreitende Miniaturisierung von elektronischen Systemen begleitet von steigender Leistung und Funktionalität führt zur Erhöhung der Leistungsdichte. Um diesem Trend zu entsprechen, werden neue Entwärmungskonzepte benötigt, die wiederum neuartige Materialien und Materialverbünde fordern. Ein wichtiger Aspekt dieser Arbeit ist deshalb die Ko...

In this study we present the capabilities of an infrared failure analysis system to (automatically) detect defects in various samples from different fields of application in electronic industries. For this purpose, we developed a production line simulator with a sample transfer via conveyor belt and an integrated pulsed infrared thermography system...

In this work we show the capabilities of non-destructive testing by pulsed infrared thermography (PIRT) on large-area silver-sinter layers. This method can achieve a similar reliability in detecting delamination as SAM and X-ray analysis. The great advantage of PIRT is its potential to become a tool for 100% in-line inspections in the production li...

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...

A composite material is a combination of two or more materials with very different mechanical, thermal and electrical properties. The various forms of composite materials, due to their high material properties, are widely used as structural materials in the aviation, space, marine, automobile, and sports industries. However, some defects like voids...

A novel microfabricated, all-electrical measurement platform is presented for a direct, accurate and rapid determination of the thermal conductivity and diffusivity of liquid and solid materials. The measurement approach is based on the bidirectional 3-omega method. The platform is composed of glass substrates on which sensor structures and a very...

We demonstrate the embedding of heat pipes as a solution for heat management in high density applications where heat spreading and heat guiding can be extremely important. Measurements results describe the advantages of the presented technology in comparison with thick copper inlays in the PCB. Further, this paper will also discuss the transient as...

Defekte elektronische Bauelemente zeigen oft eine anormale Verteilung oder zusätzliche Verlustleistungsquellen. Durch Joulesche Wärmeerzeugung führt dies zu lokalen Temperaturerhöhung. Neben stationärer Thermografie, die auf Temperaturänderung größer einiger 100 mK begrenzt ist, nutzt man die IR LockIn-Thermografie (LIT), um Temperaturänderungen bi...

The effective thermal conductivity of composites made up of silver micro-particles embedded in a resin matrix is modelled and measured. This is done for spherical and flake-like particles to analyse the effects of the particles geometry and concentration on the composite thermal performance. It is experimentally found that spherical particles yield...

This paper deals with the development of a new test stand for thermal diffusivity measurement based on Ångström's method (called TIMAwave™). The concept of the test stand has been proved by FE simulation and experiments on standard samples. The test stand has been realized and integrated into the hardware of the already existing test stand LaTIMA™,...

The effective thermal conductivity of sintered porous pastes of silver is modeled through two theoretical methods and measured by means of three experimental techniques. The first model is based on the differential effective medium theory and provides a simple analytical description considering the air pores like ellipsoidal voids of different size...

On the present work, samples of carbon fiber/epoxy composites with different void levels were fabricated using hand layup vacuum bagging process by varying the pressure. Thermal nondestructive methods: thermal conductivity measurement, pulse thermography, pulse phase thermography and lock-in-thermography, and mechanical testing: modes I and II inte...

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...

Increasing demands on efficiency, reliability and sustainability of high power electronics combined with the accompanying need of suitable new materials, raise the necessity to not only reconsider common designs and design strategies, but also to shorten and minimize the associated work on re-design and optimisation. Virtual prototyping might be an...

This paper deals with the development of a new test stand for determination the thermal conductivity of metals, semiconductors, highly conductive die attaches and substrates using the steady state technique. We designed the test stand and optimized it by FE simulation to have flexibility for the selection of the sample size and measurement paramete...

This paper deals with the system design, technology and test of a novel concept of integrating Silicon power dies along with thermo-electric coolers and a phase change heat buffer in order to thermally manage transients occurring during operation. The concept features double-sided cooling as well as new materials and joining technologies to integra...

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...

In this paper, a new and dedicated phase change cooling concept is discussed, following the goal to buffer periodic overload operations of electric power modules and thus keeping junction temperatures constant. A top-mounted latent heat storage material (LHSM) buffer is applied, to soak the overload heat in conjunction with thermo-electric coolers...

This paper deals with the system design, technology and test of a novel concept of integration Si and SiC power dies along with thermo-electric coolers in order to thermally manage transients occuring during operation. The concept features double-sided cooling as well as new material and joining technologies to integrate the dies such as transient...

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...

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...

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

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...

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...

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...