EPE Association: EPE 2007 - Subtopic 02-4 - DS: System integration & packaging

EPE 2007 - Subtopic 02-4 - DS: System integration & packaging
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2007 - Conference > EPE 2007 - Topic 02: 'Passive components, system integration & packaging' > EPE 2007 - Subtopic 02-4 - DS: System integration & packaging

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   Advanced Composite Materials with Tailored Thermal Properties for Heat Sink Applications
By NEUBAUER Erich [View]
[Download]

Abstract: Materials which are used as heat sinks should have a high thermal conductivity combined with a low coefficient of thermal expansion (CTE). Future electronic components will require heat sink materials with thermal conductivities above 300 W/mK and adapted CTEs which can be realized by diamond based composites. Aluminum and Copper-Diamond Composites have been manufactured by a powder metallurgical process. Surface coated diamonds or copper alloys have been used to prepare composites which are characterized by a stable thermal and mechanical interface. This was confirmed by measurement of thermal properties before and after thermal cycling. The used manufacturing process is a cost efficient technique which also allows to some degree the freedom for manufacturing of near net shape parts or composite parts with a high surface quality.

   Ageing Test Results of low voltage MOSFET Modules for Electrical Vehicles
By KHATIR Zoubir; DUPONT Laurent; BOUAROUDJ Mounira; LEFEBVRE StÃ©phane; FAUGIERES Jean-Claude [View]
[Download]

Abstract: HEV is one of the harshest applications for standard technology of power devices and converters. High temperature capability and passive / active thermal cycle ageing must be evaluated. Authors present first results on ageing and failure modes for a 75V/350A MOSFET module from a low voltage / cycled DC current test bench. Bond wires are used for electrical connections between dies and between dies and DCB substrates. For this kind of low voltage and high current module, the main lifetime limitation at high temperature is related to the electric connexions.

   An experimentally verified Compact Transient Electro-thermal modelingprocedure for Power systems.
By M'RAD Sabrine [View]
[Download]

Abstract: Ladders of RC-cell are usually used for compact thermal representation of power modules or assemblies. A large number of cells are considered in order to balance the intrinsic poor dynamic accuracy of the representation. However the number is limited by convergence problems in simulation. The RC-cells representation is also questionable in terms of relation to physical quantities. These limitations may be overcome using the so-called diffusive representation to build systematically a low-order but accurate thermal model of any assembly, and including thermal couplings. The paper intends to demonstrate how to build practically a diffusive model and assert its validation by experiment and through confrontation to finite-element simulations. A compact diffusive model comes as a state space model and main be easily implemented in circuit simulator.

   Base-plate solder reliability study of IGBT modules for aeronautical application
By MERMET-GUYENNET Michel; MEURET RÃ©gis; MARTIN Carmen; KARAMA Moussa; LHOMMEAU Tony [View]
[Download]

Abstract: In this work, a thermal fatigue study on IGBT modules for aeronautical application is carried out, based on accelerated thermal tests and the thermo-mechanical process simulation. The 3D thermal simulation gives us the impact of the delamination degree on the IGBT module thermal behavior and fixes the failure criterion. Element Finite thermo-mechanical simulation based and the metallurgical fatigue observations permit providing the predictive indication on the accelerated factors to predict the crack apparition and its propagation inside the solder on the basis of the creep energy dissipated.

   Comparison of stress distributions and failure modes during thermal cycling and power cycling on high power IGBT module.
By DUPONT Laurent; KHATIR Zoubir; BOUARROUDJ Mounira; OUSTEN Jean-Pierre; BADEL Frederic; LEFEBVRE Stephane [View]
[Download]

Abstract: The paper presents experimental investigations on both power and thermal cycling conditions on 600V-200A six-pack IGBT power modules. Both types of cycles are compared in term of thermo-mechanical stresses by using Finite Element simulations. Finally, combined stresses are simulated in order to assess the real conditions of use of these devices in automotive applications.

   Experimental Characterization Methods for Power MOSFET Assemblies
By REICHL Herbert; DIECKERHOFF Sibylle; KIRFE Tino; FEIX Gudrun; GUTTOWSKI Stephan; WERNICKE Thies [View]
[Download]

Abstract: In this paper, experimental methods to characterize the electrical and thermal package properties of newly developed MOSFET technology demonstrators are discussed. The electrical measurements focus on the switching characteristics and the stray inductance. From the thermal point of view, the steady-state temperature distribution within the package is measured. Exemplarily, measurement results for the FlipChip on Flex technology applying low-voltage, high current MOSFETs are used for the evaluation.

   Failure models in power device interconnects
By HANSEN Peter; MCCLUSKEY Patrick [View]
[Download]

Abstract: This paper presents failure models and associated material constants for the dominant failures in today's power modules. The developed models and material data are used in physics-of-failure based reliability assessment of power electronics for a wide range of applications. The models presented in this paper are aimed at chip and wire modules, direct interconnect technology, and pressure contacts. Mechanisms addressed include wirebond fatigue, die attach fatigue, and gate spring failure.

   Hermetic Packaging for Power Multichip Modules
By SCHULZ-HARDER JÃ¼rgen [View]
[Download]

Abstract: Hermetic packaging is a requirement for all applications where electronic components must be protected from corrosive environments to ensure acceptable service life. Extremely high reliability is required for space and military electronics, often utilizing hermetic packages. Metal packages with glass to metal seals are the common solution for low to medium power levels. For high power applications, high current has to be carried and high heat losses to be dissipated. Due to poor thermal conductivity and limited electric conductivity of metals used in standard hermetic packages, direct bond copper solutions have been developed.

   High performance cooling system for automotive inverters
By BUTTAY Cyril; RASHID Jeremy; MALHAN Rajesh Kumar; JOHNSON Mark; UDREA Florin; IRELAND Peter; AMARATUNGA Gehan [View]
[Download]

Abstract: A novel double-side cooled power module is presented which delivers superior cooling performance with the potential for improved robustness to thermal cycling. The semiconductor dies are sandwiched between conventional DBC substrates, the substrates being directly cooled rather than through a conventional heat spreader heat sink assembly. A theoretical analysis is presented illustrating that direct cooling can offer a lower total thermal resistance provided the heat transfer coefficient at the cooled surface is sufficiently high. Experimental results demonstrate the effectiveness of the selected impingement cooling technique when applied in both single- and double-side cooled formats. Measurements on the double-side cooled structure show a total thermal resistance (junction to ambient) that is less than 40\% of the junction to case resistance of a conventional module. Similar improvements are observed in the transient thermal impedance (step response) curve indicating that thermal cycling ranges will be reduced under all operational conditions

   Multi-domain simulation platform for virtual prototyping of integrated power systems.
By SAIZ JosÃ©; LAFOSSE Annick; CASTELLAZZI Alberto; SOLOMALALA Pierre; MERMET-GUYENNET Michel; FRADIN Jean-Pierre; CHAUFFLEUR Xavier [View]
[Download]

Abstract: Power electronics integration is a cross-disciplinary task. To develop reliable systems, a multi-domain physical approach is needed at all stages of the design. In the absence of well-established comprehensive solutions, simulation capability needs to be improved. This paper presents a novel technology integrated power assembly and discusses some manufacturability issues. It further proposes a virtual qualification platform in which all physics are treated with each specialist preferred simulation tool, coordinated by a custom-developed core section. A case-study demonstrates the validity of the envisaged solution.

   Optimization of Combined Thermal and Electrical Behavior of Power Converters Using Multi-Objective Genetic Algorithms
By MALYNA Dmytro; DUARTE Jorge L.; HENDRIX Marcel; VAN HORCK Frank [View]
[Download]

Abstract: A practical example of power electronic converter synthesis is presented, where a multi-objective genetic algorithm, namely Non-Dominated Sorting Genetic Algorithm (NSGA-II) is used. The optimization algorithm takes an experimentally-derived thermal model for the converter into account. Experimental results are provided for verification.

   Power Cycling Induced Failure Mechanisms in Solder Layers
By BAYERER Reinhold; HERRMANN Tobias; LUTZ Josef [View]
[Download]

Abstract: Improvements of power module technologies are investigated in different life time tests. Failure causes like solder fatigue become more important and a limiting factor for lifetime in power cycling tests. Different failure modes of solder joints in relation to power cycling conditions are shown.

   Real-Time Compact Electronic Thermal Modelling for Health Monitoring
By BUTTAY Cyril; JOHNSON Mark; MUSALLAM Mahera; WHITEHEAD Michael [View]
[Download]

Abstract: Temperature monitoring and management is emerging as an important tool for through-life cost optimization of high reliability power electronic systems. When combined with physics of failure based reliability analysis, such techniques can be employed to provide functions such as life consumption monitoring and prognostic maintenance scheduling. Requisite elements of such schemes are real-time electro-thermal models that can be used to predict the temperatures of device junctions, interfaces etc. that cannot ordinarily be measured during service. This paper presents a real-time reduced-order thermal model and its application to a half-bridge IGBT module including its associated thermal management system. Real-time electro-thermal modelling of the junction temperatures is accomplished using simplified circuit representations for the thermal model and look-up tables for the device loss estimation. The model is applied to a PWM modulated, current controlled full-bridge and implemented in dSPACE using a multi-rate computational process to improve efficiency. Validation is accomplished by comparing the model results with temperatures obtained from a high speed infra-red camera. Results are presented comparing the performance of the model for a range of PWM modulation inputs, including low frequency sine and square waves.

   Study of CVD diamond films for thermal management in power electronics
By SCHNEIDER Henri [View]
[Download]

Abstract: Because of its high thermal conductivity and dielectric strength, diamond is a promising material for thermal management in high voltage, high power electronics. In this paper we present our investigation of CVD polycrystalline diamond films for heat sink applications. Dielectric strength and thermal conductivity have been measured at room temperature, for either home made or commercial samples. Though the measured dielectric strength remains lower than the 10 MV/cm expected value (greatly impacted by the surface polishing), the interest of diamond is confirmed.

EPE 2007 - Subtopic 02-4 - DS: System integration & packaging
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2007 - Conference > EPE 2007 - Topic 02: 'Passive components, system integration & packaging' > EPE 2007 - Subtopic 02-4 - DS: System integration & packaging
	[return to parent folder]

	Advanced Composite Materials with Tailored Thermal Properties for Heat Sink Applications By NEUBAUER Erich	[View] [Download]
Abstract: Materials which are used as heat sinks should have a high thermal conductivity combined with a low coefficient of thermal expansion (CTE). Future electronic components will require heat sink materials with thermal conductivities above 300 W/mK and adapted CTEs which can be realized by diamond based composites. Aluminum and Copper-Diamond Composites have been manufactured by a powder metallurgical process. Surface coated diamonds or copper alloys have been used to prepare composites which are characterized by a stable thermal and mechanical interface. This was confirmed by measurement of thermal properties before and after thermal cycling. The used manufacturing process is a cost efficient technique which also allows to some degree the freedom for manufacturing of near net shape parts or composite parts with a high surface quality.

	Ageing Test Results of low voltage MOSFET Modules for Electrical Vehicles By KHATIR Zoubir; DUPONT Laurent; BOUAROUDJ Mounira; LEFEBVRE StÃ©phane; FAUGIERES Jean-Claude	[View] [Download]
Abstract: HEV is one of the harshest applications for standard technology of power devices and converters. High temperature capability and passive / active thermal cycle ageing must be evaluated. Authors present first results on ageing and failure modes for a 75V/350A MOSFET module from a low voltage / cycled DC current test bench. Bond wires are used for electrical connections between dies and between dies and DCB substrates. For this kind of low voltage and high current module, the main lifetime limitation at high temperature is related to the electric connexions.

	An experimentally verified Compact Transient Electro-thermal modelingprocedure for Power systems. By M'RAD Sabrine	[View] [Download]
Abstract: Ladders of RC-cell are usually used for compact thermal representation of power modules or assemblies. A large number of cells are considered in order to balance the intrinsic poor dynamic accuracy of the representation. However the number is limited by convergence problems in simulation. The RC-cells representation is also questionable in terms of relation to physical quantities. These limitations may be overcome using the so-called diffusive representation to build systematically a low-order but accurate thermal model of any assembly, and including thermal couplings. The paper intends to demonstrate how to build practically a diffusive model and assert its validation by experiment and through confrontation to finite-element simulations. A compact diffusive model comes as a state space model and main be easily implemented in circuit simulator.

	Base-plate solder reliability study of IGBT modules for aeronautical application By MERMET-GUYENNET Michel; MEURET RÃ©gis; MARTIN Carmen; KARAMA Moussa; LHOMMEAU Tony	[View] [Download]
Abstract: In this work, a thermal fatigue study on IGBT modules for aeronautical application is carried out, based on accelerated thermal tests and the thermo-mechanical process simulation. The 3D thermal simulation gives us the impact of the delamination degree on the IGBT module thermal behavior and fixes the failure criterion. Element Finite thermo-mechanical simulation based and the metallurgical fatigue observations permit providing the predictive indication on the accelerated factors to predict the crack apparition and its propagation inside the solder on the basis of the creep energy dissipated.

	Comparison of stress distributions and failure modes during thermal cycling and power cycling on high power IGBT module. By DUPONT Laurent; KHATIR Zoubir; BOUARROUDJ Mounira; OUSTEN Jean-Pierre; BADEL Frederic; LEFEBVRE Stephane	[View] [Download]
Abstract: The paper presents experimental investigations on both power and thermal cycling conditions on 600V-200A six-pack IGBT power modules. Both types of cycles are compared in term of thermo-mechanical stresses by using Finite Element simulations. Finally, combined stresses are simulated in order to assess the real conditions of use of these devices in automotive applications.

	Experimental Characterization Methods for Power MOSFET Assemblies By REICHL Herbert; DIECKERHOFF Sibylle; KIRFE Tino; FEIX Gudrun; GUTTOWSKI Stephan; WERNICKE Thies	[View] [Download]
Abstract: In this paper, experimental methods to characterize the electrical and thermal package properties of newly developed MOSFET technology demonstrators are discussed. The electrical measurements focus on the switching characteristics and the stray inductance. From the thermal point of view, the steady-state temperature distribution within the package is measured. Exemplarily, measurement results for the FlipChip on Flex technology applying low-voltage, high current MOSFETs are used for the evaluation.

	Failure models in power device interconnects By HANSEN Peter; MCCLUSKEY Patrick	[View] [Download]
Abstract: This paper presents failure models and associated material constants for the dominant failures in today's power modules. The developed models and material data are used in physics-of-failure based reliability assessment of power electronics for a wide range of applications. The models presented in this paper are aimed at chip and wire modules, direct interconnect technology, and pressure contacts. Mechanisms addressed include wirebond fatigue, die attach fatigue, and gate spring failure.

	Hermetic Packaging for Power Multichip Modules By SCHULZ-HARDER JÃ¼rgen	[View] [Download]
Abstract: Hermetic packaging is a requirement for all applications where electronic components must be protected from corrosive environments to ensure acceptable service life. Extremely high reliability is required for space and military electronics, often utilizing hermetic packages. Metal packages with glass to metal seals are the common solution for low to medium power levels. For high power applications, high current has to be carried and high heat losses to be dissipated. Due to poor thermal conductivity and limited electric conductivity of metals used in standard hermetic packages, direct bond copper solutions have been developed.

	High performance cooling system for automotive inverters By BUTTAY Cyril; RASHID Jeremy; MALHAN Rajesh Kumar; JOHNSON Mark; UDREA Florin; IRELAND Peter; AMARATUNGA Gehan	[View] [Download]
Abstract: A novel double-side cooled power module is presented which delivers superior cooling performance with the potential for improved robustness to thermal cycling. The semiconductor dies are sandwiched between conventional DBC substrates, the substrates being directly cooled rather than through a conventional heat spreader heat sink assembly. A theoretical analysis is presented illustrating that direct cooling can offer a lower total thermal resistance provided the heat transfer coefficient at the cooled surface is sufficiently high. Experimental results demonstrate the effectiveness of the selected impingement cooling technique when applied in both single- and double-side cooled formats. Measurements on the double-side cooled structure show a total thermal resistance (junction to ambient) that is less than 40\% of the junction to case resistance of a conventional module. Similar improvements are observed in the transient thermal impedance (step response) curve indicating that thermal cycling ranges will be reduced under all operational conditions

	Multi-domain simulation platform for virtual prototyping of integrated power systems. By SAIZ JosÃ©; LAFOSSE Annick; CASTELLAZZI Alberto; SOLOMALALA Pierre; MERMET-GUYENNET Michel; FRADIN Jean-Pierre; CHAUFFLEUR Xavier	[View] [Download]
Abstract: Power electronics integration is a cross-disciplinary task. To develop reliable systems, a multi-domain physical approach is needed at all stages of the design. In the absence of well-established comprehensive solutions, simulation capability needs to be improved. This paper presents a novel technology integrated power assembly and discusses some manufacturability issues. It further proposes a virtual qualification platform in which all physics are treated with each specialist preferred simulation tool, coordinated by a custom-developed core section. A case-study demonstrates the validity of the envisaged solution.

	Optimization of Combined Thermal and Electrical Behavior of Power Converters Using Multi-Objective Genetic Algorithms By MALYNA Dmytro; DUARTE Jorge L.; HENDRIX Marcel; VAN HORCK Frank	[View] [Download]
Abstract: A practical example of power electronic converter synthesis is presented, where a multi-objective genetic algorithm, namely Non-Dominated Sorting Genetic Algorithm (NSGA-II) is used. The optimization algorithm takes an experimentally-derived thermal model for the converter into account. Experimental results are provided for verification.

	Power Cycling Induced Failure Mechanisms in Solder Layers By BAYERER Reinhold; HERRMANN Tobias; LUTZ Josef	[View] [Download]
Abstract: Improvements of power module technologies are investigated in different life time tests. Failure causes like solder fatigue become more important and a limiting factor for lifetime in power cycling tests. Different failure modes of solder joints in relation to power cycling conditions are shown.

	Real-Time Compact Electronic Thermal Modelling for Health Monitoring By BUTTAY Cyril; JOHNSON Mark; MUSALLAM Mahera; WHITEHEAD Michael	[View] [Download]
Abstract: Temperature monitoring and management is emerging as an important tool for through-life cost optimization of high reliability power electronic systems. When combined with physics of failure based reliability analysis, such techniques can be employed to provide functions such as life consumption monitoring and prognostic maintenance scheduling. Requisite elements of such schemes are real-time electro-thermal models that can be used to predict the temperatures of device junctions, interfaces etc. that cannot ordinarily be measured during service. This paper presents a real-time reduced-order thermal model and its application to a half-bridge IGBT module including its associated thermal management system. Real-time electro-thermal modelling of the junction temperatures is accomplished using simplified circuit representations for the thermal model and look-up tables for the device loss estimation. The model is applied to a PWM modulated, current controlled full-bridge and implemented in dSPACE using a multi-rate computational process to improve efficiency. Validation is accomplished by comparing the model results with temperatures obtained from a high speed infra-red camera. Results are presented comparing the performance of the model for a range of PWM modulation inputs, including low frequency sine and square waves.

	Study of CVD diamond films for thermal management in power electronics By SCHNEIDER Henri	[View] [Download]
Abstract: Because of its high thermal conductivity and dielectric strength, diamond is a promising material for thermal management in high voltage, high power electronics. In this paper we present our investigation of CVD polycrystalline diamond films for heat sink applications. Dielectric strength and thermal conductivity have been measured at room temperature, for either home made or commercial samples. Though the measured dielectric strength remains lower than the 10 MV/cm expected value (greatly impacted by the surface polishing), the interest of diamond is confirmed.