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Ahlem Baazaoui

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Papers by Ahlem Baazaoui

Caractérisation expérimentale du comportement mécanique d’assemblage haute température pour l’électronique de puissance

HAL (Le Centre pour la Communication Scientifique Directe), Oct 29, 2013

Thermomechanical optimization of a diamond-die high temperature packaging for power electronics

L’accroissement des besoins en énergie électrique pour les systèmes embarqués et leur augmentatio... more L’accroissement des besoins en énergie électrique pour les systèmes embarqués et leur augmentation de puissance nécessitent de concevoir des systèmes d’électronique de puissance toujours plus performants. Une solution d’avenir concerne la mise en œuvre de composants à base de diamant qui permettent l’augmentation conséquente des tensions et courants mis en jeux, mais aussi de la température maximale de jonction admissible. Le cadre de ces travaux est celui du projet de recherche Diamonix 2, qui concerne l’étude et l’élaboration d’un composant diamant fonctionnant à haute température. L’objectif du travail doctoral présenté ici est l’étude du packaging haute température de ce type de composant diamant. Plusieurs choix de matériaux et de techniques aptes à l’élaboration d’un assemblage de puce diamant sur un substrat métallisé ont été effectués. La caractérisation microstructurale et mécanique de trois types de jonctions ont été réalisées (refusion d’un alliage AuGe, frittage de nano ...

Caractérisation expérimentale du comportement mécanique d'assemblage haute température pour l'électronique de puissance

MATEC Web of Conferences, 2013

The mechanical behavior of two types of high-temperature connection implemented in the assembly o... more The mechanical behavior of two types of high-temperature connection implemented in the assembly of electronic power components was studied: a joint made by brazing transient liquid phase (TLPB) Ag-In and in another by brazing Au88Ge12. Connections made are mechanically characterized using shear tests. The microstructure of the junction section and the fracture surfaces of both connections was also observed. Résumé. Le comportement mécanique de deux types de connexion haute température mises en oeuvre pour l'assemblage de composants d'électronique de puissance aétéétudié : une jonction réalisée par brasage en phase liquide transitoire (TLPB) d'Ag-In et une autre par brasage d'un eutectique Au88Ge12. Les connexions réaliséesà partir d'inserts de cuivre sont caractérisées mécaniquement au moyen d'essais de cisaillement. Une analyse de la microstructure des jonctions en coupe et des faciès de rupture des deux connexions aégalementété menée.

Viscoplastic behavior of diamond die attach subjected to high temperature conditions

2012 13th International Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2012, 2012

In power electronic applications, diamond based semiconductors appears to be a new way to widely ... more In power electronic applications, diamond based semiconductors appears to be a new way to widely increase the capabilities of power electronic converters [1, 2]. The main prospective expected is an increasing in system integration and power capabilities. The Diamonix project concerns the elaboration of a single-crystal diamond substrate with electronic quality and its associated packaging. The designed structure has to resist to temperatures varying between-50°C and +300°C. This paper deals with an experimental and numerical study of the diamond die attach solution. The development of a packaging for diamond component relies in particular on a specific choice of solder's alloys for the junction die/substrate. To carry out this junction, AuGe and AlSi eutectic alloys were chosen and characterized; the choice of these two kinds of solders i.e. AuGe and AlSi is motivated by the practical elaboration process and the restrictions of hazardous substances (RoHS). The first solder has a melting temperature of 356°C; the second has a higher melting point of 577°C. In this paper, we present some numerical results obtained from FE simulations of two 2D configurations of simplified electronic packaging. The power electronic packaging is composed of a diamond die and a copper metallized Si 3 N 4 ceramic substrate which are brazed together with either AuGe or AlSi solder alloy. To predict the thermomechanical behavior of the solders, a particular constitutive behavior law was implemented as a User MATerial subroutine which is based on a viscoplastic unified McDowell formulation, coupled with porous damage equations. The mechanical law can describe precisely the viscoplastic damage phenomenon of solder subjected to high thermal cycling and to optimize the thermo-mechanical modeling for advanced package development.

Of Diamond Die Attach Subjected to High Temperature Conditions

In power electronic applications, diamond based semi conductors appears to be a new way to widel... more In power electronic applications, diamond based semi conductors appears to be a new way to widely increase the capabilities of power electronic converters [1,2]. The main prospective expected is an increasing in system integration and power capabilities. The Diamonix project concerns the elaboration of a single-crystal diamond substrate with electronic quality and its associated packaging. The designed structure has to resist to temperatures varying between -50oe and + 300°C. This paper deals with an experimental and numerical study of the diamond die attach solution. The development of a packaging for diamond component relies in particular on a specific choice of solder's alloys for the junction die/substrate. To carry out this junction, AuGe and AISi eutectic alloys were chosen and characterized ; the choice of these two kinds of solders i.e. AuGe and AISi is motivated by the practical elaboration process and the restrictions of hazardous substances (RoHS). The first solder h...

Numerical modeling and prediction of thermomechanical degradation of power electronic packaging

This work aims at numerical thermomechanical studies of two types of high temperature silver conn... more This work aims at numerical thermomechanical studies of two types of high temperature silver connections elaborated at low temperatures, the transient liquid phase bonding (TLPB) of Ag-In and silver nanoparticles sintering, using test vehicles representing the final packaging assemblies of diamond components. The simulation is performed using a finite element code on 2D and 3D assemblies. The stress distribution in the assemblies and in the two die-attachments was studied during thermal cycling in the range temperature between -50 and 300°C. A comparison of these two technology trends with respect to their applicability for power electronics packaging was conducted.

Study and mechanical characterization of high temperature power electronic packaging

The increase of electric power demand for embedded systems requires more efficient power electron... more The increase of electric power demand for embedded systems requires more efficient power electronics modules (power converters, rectifiers ...). A solution to reach this goal relates to the use of high gap electronic chips as diamond-based components that allow high voltage and current density. The induced module design obviously sorely increases the maximum thermal and thermomechanical stresses in the packaged modules. In this work, we carry out experimental and numerical investigations of two types of high temperature silver connections elaborated at low temperatures by means diffusion heat treatment and by sintering. Mechanical behaviour of the junction is characterized by shear tests. At last, numerical simulations are used to simulate process and services thermal cycles and to assess stresses level at several stages of the assembly service life. All testing and simulation works allow validating the accuracy of the two kinds of connections and demonstrating their interest.

Optimisation thermomécanique du packaging haute température d’un composant diamant pour l’électronique de puissance

L’accroissement des besoins en energie electrique pour les systemes embarques et leur augmentatio... more L’accroissement des besoins en energie electrique pour les systemes embarques et leur augmentation de puissance necessitent de concevoir des systemes d’electronique de puissance toujours plus performants. Une solution d’avenir concerne la mise en œuvre de composants a base de diamant qui permettent l’augmentation consequente des tensions et courants mis en jeux, mais aussi de la temperature maximale de jonction admissible. Le cadre de ces travaux est celui du projet de recherche Diamonix 2, qui concerne l’etude et l’elaboration d’un composant diamant fonctionnant a haute temperature. L’objectif du travail doctoral presente ici est l’etude du packaging haute temperature de ce type de composant diamant. Plusieurs choix de materiaux et de techniques aptes a l’elaboration d’un assemblage de puce diamant sur un substrat metallise ont ete effectues. La caracterisation microstructurale et mecanique de trois types de jonctions ont ete realisees (refusion d’un alliage AuGe, frittage de nano ...

$Research paper thumbnail of Identification of damage and fracture modes in power electronic packaging from experimental micro-shear tests and finite element modeling$

Identification of damage and fracture modes in power electronic packaging from experimental micro-shear tests and finite element modeling

Micro-shear tests are performed in order to characterize the mechanical behavior and the fracture... more Micro-shear tests are performed in order to characterize the mechanical behavior and the fracture of the chip/metallized ceramic substrate assemblies of power electronic devices. These assemblies are elaborated using three types of junctions: AuGe solder/Au or Ag finish, transient liquid phase bonding (TLPB) AgIn/Ag finish and Ag nanoparticles/Au or Ag finish. The experiments are associated to finite element simulations of both nano-indentation and micro-shear tests. The mechanical behavior of the different assembly interfaces is represented using an in-built cohesive zone model (CZM) available in the user friendly finite element code Abaqus. It is worth noting that the fracture mechanisms observed during the test and service periods of the power electronic packaging are not only due to the debonding at the interfaces but also to the initiation and growth of voids in the joint. Therefore, in addition to the CZM model, Gurson-Tvergaard-Needlmann (GTN) damage model is used in combinat...

Experimental and Numerical Study of Interfacial Fracture Parameters of a Brazed Joints

Advanced Materials Research, 2015

This paper deals with an identification methodology of the interfacial fracture parameters to pre... more This paper deals with an identification methodology of the interfacial fracture parameters to predict the lifetime of a metallic brazed joint. The methodology is based on an experimental-numerical study whereby the optimal parameters are obtained. The experimental data, using the scanning electron microscope analysis, allowed approving that failure of the assembly based AuGe solder seems first to appear near the interfaces. These results were confirmed by micrographs analysis of the solder/insert and solder/substrate interfaces. Then, using shear test results and parametric identification coupled with a finite elements model (FEM) simulation, the damage constitutive law of the interfacial fracture based on a bilinear cohesive zone model are identified. The agreement between the numerical results and the experimental data shows the applicability of the cohesive zone model to fatigue crack growth analysis and life estimation of brazed joints.

Numerical modeling and prediction of thermomechanical degradation of power electronic packaging

Study and mechanical characterization of high temperature power electronic packaging

Caractérisation expérimentale du comportement mécanique d'assemblage haute température pour l'électronique de puissance

by Ahlem Baazaoui and joel alexis

MATEC Web of Conferences, 2013

Viscoplastic behavior of diamond die attach subjected to high temperature conditions

by Ahlem Baazaoui, joel alexis, and Sabeur Msolli

2012 13th International Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2012, 2012

In power electronic applications, diamond based semi conductors appears to be a new way to widely... more

Caractérisation expérimentale du comportement mécanique d’assemblage haute température pour l’électronique de puissance

HAL (Le Centre pour la Communication Scientifique Directe), Oct 29, 2013

Thermomechanical optimization of a diamond-die high temperature packaging for power electronics

L’accroissement des besoins en énergie électrique pour les systèmes embarqués et leur augmentatio... more L’accroissement des besoins en énergie électrique pour les systèmes embarqués et leur augmentation de puissance nécessitent de concevoir des systèmes d’électronique de puissance toujours plus performants. Une solution d’avenir concerne la mise en œuvre de composants à base de diamant qui permettent l’augmentation conséquente des tensions et courants mis en jeux, mais aussi de la température maximale de jonction admissible. Le cadre de ces travaux est celui du projet de recherche Diamonix 2, qui concerne l’étude et l’élaboration d’un composant diamant fonctionnant à haute température. L’objectif du travail doctoral présenté ici est l’étude du packaging haute température de ce type de composant diamant. Plusieurs choix de matériaux et de techniques aptes à l’élaboration d’un assemblage de puce diamant sur un substrat métallisé ont été effectués. La caractérisation microstructurale et mécanique de trois types de jonctions ont été réalisées (refusion d’un alliage AuGe, frittage de nano ...

Caractérisation expérimentale du comportement mécanique d'assemblage haute température pour l'électronique de puissance

MATEC Web of Conferences, 2013

The mechanical behavior of two types of high-temperature connection implemented in the assembly o... more The mechanical behavior of two types of high-temperature connection implemented in the assembly of electronic power components was studied: a joint made by brazing transient liquid phase (TLPB) Ag-In and in another by brazing Au88Ge12. Connections made are mechanically characterized using shear tests. The microstructure of the junction section and the fracture surfaces of both connections was also observed. Résumé. Le comportement mécanique de deux types de connexion haute température mises en oeuvre pour l'assemblage de composants d'électronique de puissance aétéétudié : une jonction réalisée par brasage en phase liquide transitoire (TLPB) d'Ag-In et une autre par brasage d'un eutectique Au88Ge12. Les connexions réaliséesà partir d'inserts de cuivre sont caractérisées mécaniquement au moyen d'essais de cisaillement. Une analyse de la microstructure des jonctions en coupe et des faciès de rupture des deux connexions aégalementété menée.

Viscoplastic behavior of diamond die attach subjected to high temperature conditions

2012 13th International Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2012, 2012

In power electronic applications, diamond based semiconductors appears to be a new way to widely ... more In power electronic applications, diamond based semiconductors appears to be a new way to widely increase the capabilities of power electronic converters [1, 2]. The main prospective expected is an increasing in system integration and power capabilities. The Diamonix project concerns the elaboration of a single-crystal diamond substrate with electronic quality and its associated packaging. The designed structure has to resist to temperatures varying between-50°C and +300°C. This paper deals with an experimental and numerical study of the diamond die attach solution. The development of a packaging for diamond component relies in particular on a specific choice of solder's alloys for the junction die/substrate. To carry out this junction, AuGe and AlSi eutectic alloys were chosen and characterized; the choice of these two kinds of solders i.e. AuGe and AlSi is motivated by the practical elaboration process and the restrictions of hazardous substances (RoHS). The first solder has a melting temperature of 356°C; the second has a higher melting point of 577°C. In this paper, we present some numerical results obtained from FE simulations of two 2D configurations of simplified electronic packaging. The power electronic packaging is composed of a diamond die and a copper metallized Si 3 N 4 ceramic substrate which are brazed together with either AuGe or AlSi solder alloy. To predict the thermomechanical behavior of the solders, a particular constitutive behavior law was implemented as a User MATerial subroutine which is based on a viscoplastic unified McDowell formulation, coupled with porous damage equations. The mechanical law can describe precisely the viscoplastic damage phenomenon of solder subjected to high thermal cycling and to optimize the thermo-mechanical modeling for advanced package development.

Of Diamond Die Attach Subjected to High Temperature Conditions

In power electronic applications, diamond based semi conductors appears to be a new way to widel... more In power electronic applications, diamond based semi conductors appears to be a new way to widely increase the capabilities of power electronic converters [1,2]. The main prospective expected is an increasing in system integration and power capabilities. The Diamonix project concerns the elaboration of a single-crystal diamond substrate with electronic quality and its associated packaging. The designed structure has to resist to temperatures varying between -50oe and + 300°C. This paper deals with an experimental and numerical study of the diamond die attach solution. The development of a packaging for diamond component relies in particular on a specific choice of solder's alloys for the junction die/substrate. To carry out this junction, AuGe and AISi eutectic alloys were chosen and characterized ; the choice of these two kinds of solders i.e. AuGe and AISi is motivated by the practical elaboration process and the restrictions of hazardous substances (RoHS). The first solder h...

Numerical modeling and prediction of thermomechanical degradation of power electronic packaging

This work aims at numerical thermomechanical studies of two types of high temperature silver conn... more This work aims at numerical thermomechanical studies of two types of high temperature silver connections elaborated at low temperatures, the transient liquid phase bonding (TLPB) of Ag-In and silver nanoparticles sintering, using test vehicles representing the final packaging assemblies of diamond components. The simulation is performed using a finite element code on 2D and 3D assemblies. The stress distribution in the assemblies and in the two die-attachments was studied during thermal cycling in the range temperature between -50 and 300°C. A comparison of these two technology trends with respect to their applicability for power electronics packaging was conducted.

Study and mechanical characterization of high temperature power electronic packaging

The increase of electric power demand for embedded systems requires more efficient power electron... more The increase of electric power demand for embedded systems requires more efficient power electronics modules (power converters, rectifiers ...). A solution to reach this goal relates to the use of high gap electronic chips as diamond-based components that allow high voltage and current density. The induced module design obviously sorely increases the maximum thermal and thermomechanical stresses in the packaged modules. In this work, we carry out experimental and numerical investigations of two types of high temperature silver connections elaborated at low temperatures by means diffusion heat treatment and by sintering. Mechanical behaviour of the junction is characterized by shear tests. At last, numerical simulations are used to simulate process and services thermal cycles and to assess stresses level at several stages of the assembly service life. All testing and simulation works allow validating the accuracy of the two kinds of connections and demonstrating their interest.

Optimisation thermomécanique du packaging haute température d’un composant diamant pour l’électronique de puissance

L’accroissement des besoins en energie electrique pour les systemes embarques et leur augmentatio... more L’accroissement des besoins en energie electrique pour les systemes embarques et leur augmentation de puissance necessitent de concevoir des systemes d’electronique de puissance toujours plus performants. Une solution d’avenir concerne la mise en œuvre de composants a base de diamant qui permettent l’augmentation consequente des tensions et courants mis en jeux, mais aussi de la temperature maximale de jonction admissible. Le cadre de ces travaux est celui du projet de recherche Diamonix 2, qui concerne l’etude et l’elaboration d’un composant diamant fonctionnant a haute temperature. L’objectif du travail doctoral presente ici est l’etude du packaging haute temperature de ce type de composant diamant. Plusieurs choix de materiaux et de techniques aptes a l’elaboration d’un assemblage de puce diamant sur un substrat metallise ont ete effectues. La caracterisation microstructurale et mecanique de trois types de jonctions ont ete realisees (refusion d’un alliage AuGe, frittage de nano ...

$Research paper thumbnail of Identification of damage and fracture modes in power electronic packaging from experimental micro-shear tests and finite element modeling$

Identification of damage and fracture modes in power electronic packaging from experimental micro-shear tests and finite element modeling

Micro-shear tests are performed in order to characterize the mechanical behavior and the fracture... more Micro-shear tests are performed in order to characterize the mechanical behavior and the fracture of the chip/metallized ceramic substrate assemblies of power electronic devices. These assemblies are elaborated using three types of junctions: AuGe solder/Au or Ag finish, transient liquid phase bonding (TLPB) AgIn/Ag finish and Ag nanoparticles/Au or Ag finish. The experiments are associated to finite element simulations of both nano-indentation and micro-shear tests. The mechanical behavior of the different assembly interfaces is represented using an in-built cohesive zone model (CZM) available in the user friendly finite element code Abaqus. It is worth noting that the fracture mechanisms observed during the test and service periods of the power electronic packaging are not only due to the debonding at the interfaces but also to the initiation and growth of voids in the joint. Therefore, in addition to the CZM model, Gurson-Tvergaard-Needlmann (GTN) damage model is used in combinat...

Experimental and Numerical Study of Interfacial Fracture Parameters of a Brazed Joints

Advanced Materials Research, 2015

This paper deals with an identification methodology of the interfacial fracture parameters to pre... more This paper deals with an identification methodology of the interfacial fracture parameters to predict the lifetime of a metallic brazed joint. The methodology is based on an experimental-numerical study whereby the optimal parameters are obtained. The experimental data, using the scanning electron microscope analysis, allowed approving that failure of the assembly based AuGe solder seems first to appear near the interfaces. These results were confirmed by micrographs analysis of the solder/insert and solder/substrate interfaces. Then, using shear test results and parametric identification coupled with a finite elements model (FEM) simulation, the damage constitutive law of the interfacial fracture based on a bilinear cohesive zone model are identified. The agreement between the numerical results and the experimental data shows the applicability of the cohesive zone model to fatigue crack growth analysis and life estimation of brazed joints.

Numerical modeling and prediction of thermomechanical degradation of power electronic packaging

Study and mechanical characterization of high temperature power electronic packaging

Caractérisation expérimentale du comportement mécanique d'assemblage haute température pour l'électronique de puissance

by Ahlem Baazaoui and joel alexis

MATEC Web of Conferences, 2013

Viscoplastic behavior of diamond die attach subjected to high temperature conditions

by Ahlem Baazaoui, joel alexis, and Sabeur Msolli

2012 13th International Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2012, 2012

In power electronic applications, diamond based semi conductors appears to be a new way to widely... more