EPE Association: EPE 2013 - LS2c: Passive Components, System Integration & Packaging

EPE 2013 - LS2c: Passive Components, System Integration & Packaging
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2013 ECCE Europe - Conference > EPE 2013 - Topic 02: Passive components, system integration & packaging > EPE 2013 - LS2c: Passive Components, System Integration & Packaging

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   Assessment of selected materials and assembly technologies for power electronics modules with the capability to operate at high temperatures
By Joris HAMERS, Slavo KICIN [View]
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Abstract: Wide-band gap semiconductors allow operation of power electronics at considerably higher temperatures than Si-devices. However, a significant improvement of a power module temperature capability is necessary to fully exploit this benefit. For this reason reliability of various ceramic substrates undergoing liquid-liquid thermal shock cycling -50 – 190 C was tested. Additionally, an impact of the large temperature-span shock cycling on module assembly technologies was studied with focus on Ag-sintering. The benchmarked DUTs were mainly investigated using scanning acoustic microscopy, scanning electron microscopy and laser profilometry. The obtained results were compared with performance of CTE optimized double-side cooled module prototypes.Data presented in this paper extend already published information. For example, the sintered bond of a SiC diode and an AlN/Al substrate was more robust against cycling than the bond of a SiC diode and a Si3N4/Cu substrate. On the other hand, Si3N4/Cu substrates were significantly more robust than AlN/Al substrates. It was also observed that roughening of Al-metallization can be strongly modified by adding of additional elements. CTE optimized double-side cooled modules were showing high reliability of interconnections; however, a different failure mode – cracking of semiconductor chips was seen.

   Impact of Absolute Junction Temperature on Power Cycling Lifetime
By Ralf SCHMIDT, Felix ZEYSS, Uwe SCHEUERMANN [View]
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Abstract: The influence of the absolute junction temperature Tj on IGBT power module lifetime was systematically investigated by means of active power cycling tests. Both the impact on the wire bond lift-off and thechip solder degradation mechanism could be determined separately by applying the concept of separating failure modes. The test results not only prove that classical lifetime models overestimate the influence of Tj , but also show that the two dominant failure mechanisms have to be treated differently. The wire bond lift-off failure mode is weakly affected by the absolute temperature level and possesses a very small activation energy of 0.069 eV. The solder degradation mode exhibits a significantly larger activation energy of 0.159 eV, which results in a massive decrease (factor 3) in power cycling capability when increasing Tj by 85K. For junction temperatures above 175C SnAg-based solder joints are no longer suitable for reliable power module designs and advanced die attach technologies such as silver sintering have to be deployed. For the description of such advanced power modules specific lifetime curves are under development which exclusively represent the pure wire bond lifetime, as for common power cycling conditions the silver sintered die attach is not subjected to ageing.

   Multi-switch Si-chip structures and on-substrate packaging techniques for improving the electrical performance of power modules
By Abdelilah EL KHADIRY, Frederic RICHARDEAU, Abdelhakim BOURENNANE, Dou ZHIFENG, Marie BREIL [View]
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Abstract: Starting from the common anode and common cathode multi-switch Si-chips, this paper focuses on the different association techniques of the two power chips on the usual substrates (DBC/IMS). The study uses 3D multiphysics COMSOL simulations to determine the best association that would allow the best electrical performance of power converters.

   Real-time degradation monitoring and lifetime estimation of 3D integrated bond-wire-less double-sided cooled power switch technologies
By Tianxiang DAI, Jian Feng LI, Martin CORFIELD, Alberto CASTELLAZZI, Pat WHEELER [View]
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Abstract: This paper presents the development of an integrated power switch using Copper-Molybdenum-Copper interconnects for improved reliability and introduces a methodology for real-time degradation monitoring and reliability assessment of novel sandwich-type integrated power switches during passive thermal cycling. The proposed approach enables to realistically monitor degradation from time zero, allowing the flexible definition of the most suitable failure criteria and test time.

EPE 2013 - LS2c: Passive Components, System Integration & Packaging
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2013 ECCE Europe - Conference > EPE 2013 - Topic 02: Passive components, system integration & packaging > EPE 2013 - LS2c: Passive Components, System Integration & Packaging
	[return to parent folder]

	Assessment of selected materials and assembly technologies for power electronics modules with the capability to operate at high temperatures By Joris HAMERS, Slavo KICIN	[View] [Download]
Abstract: Wide-band gap semiconductors allow operation of power electronics at considerably higher temperatures than Si-devices. However, a significant improvement of a power module temperature capability is necessary to fully exploit this benefit. For this reason reliability of various ceramic substrates undergoing liquid-liquid thermal shock cycling -50 – 190 C was tested. Additionally, an impact of the large temperature-span shock cycling on module assembly technologies was studied with focus on Ag-sintering. The benchmarked DUTs were mainly investigated using scanning acoustic microscopy, scanning electron microscopy and laser profilometry. The obtained results were compared with performance of CTE optimized double-side cooled module prototypes.Data presented in this paper extend already published information. For example, the sintered bond of a SiC diode and an AlN/Al substrate was more robust against cycling than the bond of a SiC diode and a Si3N4/Cu substrate. On the other hand, Si3N4/Cu substrates were significantly more robust than AlN/Al substrates. It was also observed that roughening of Al-metallization can be strongly modified by adding of additional elements. CTE optimized double-side cooled modules were showing high reliability of interconnections; however, a different failure mode – cracking of semiconductor chips was seen.

	Impact of Absolute Junction Temperature on Power Cycling Lifetime By Ralf SCHMIDT, Felix ZEYSS, Uwe SCHEUERMANN	[View] [Download]
Abstract: The influence of the absolute junction temperature Tj on IGBT power module lifetime was systematically investigated by means of active power cycling tests. Both the impact on the wire bond lift-off and thechip solder degradation mechanism could be determined separately by applying the concept of separating failure modes. The test results not only prove that classical lifetime models overestimate the influence of Tj , but also show that the two dominant failure mechanisms have to be treated differently. The wire bond lift-off failure mode is weakly affected by the absolute temperature level and possesses a very small activation energy of 0.069 eV. The solder degradation mode exhibits a significantly larger activation energy of 0.159 eV, which results in a massive decrease (factor 3) in power cycling capability when increasing Tj by 85K. For junction temperatures above 175C SnAg-based solder joints are no longer suitable for reliable power module designs and advanced die attach technologies such as silver sintering have to be deployed. For the description of such advanced power modules specific lifetime curves are under development which exclusively represent the pure wire bond lifetime, as for common power cycling conditions the silver sintered die attach is not subjected to ageing.

	Multi-switch Si-chip structures and on-substrate packaging techniques for improving the electrical performance of power modules By Abdelilah EL KHADIRY, Frederic RICHARDEAU, Abdelhakim BOURENNANE, Dou ZHIFENG, Marie BREIL	[View] [Download]
Abstract: Starting from the common anode and common cathode multi-switch Si-chips, this paper focuses on the different association techniques of the two power chips on the usual substrates (DBC/IMS). The study uses 3D multiphysics COMSOL simulations to determine the best association that would allow the best electrical performance of power converters.

	Real-time degradation monitoring and lifetime estimation of 3D integrated bond-wire-less double-sided cooled power switch technologies By Tianxiang DAI, Jian Feng LI, Martin CORFIELD, Alberto CASTELLAZZI, Pat WHEELER	[View] [Download]
Abstract: This paper presents the development of an integrated power switch using Copper-Molybdenum-Copper interconnects for improved reliability and introduces a methodology for real-time degradation monitoring and reliability assessment of novel sandwich-type integrated power switches during passive thermal cycling. The proposed approach enables to realistically monitor degradation from time zero, allowing the flexible definition of the most suitable failure criteria and test time.