Electronic devices using semiconductors such as insulated-gate bipolar transistors, metal–oxide–semiconductor field-effect transistors, and diodes are extensively used in electrical traction applications such as locomotive, elevators, subways, and cars. The long-term reliability of such power modules is then highly demanded, and their main reliability criterion is their power cycling capability. Thus, a power cycling test is the most important reliability test for power modules. This test consists in periodically applying a current to a device mounted onto a heat sink. This leads to power loss in the entire module and results in a rise in the semiconductor temperature. In this paper, the different kinds of semiconductors and power modules used for traction applications are described. Experimental and simulation methods employed for power cycling tests are presented. Modules' weak points and fatigue processes are pointed out. Then, a detailed statistical review of publications from 1994 to 2015 dealing with power cycling is presented. This review gives a clear overview of all studies dealing with power cycling that were carried out until now. It reveals the principal trends in power electronic devices and highlights the main reliability issues for which an important lack of knowledge remains.

Power Cycling Reliability of Power Module: A Survey

Analysis on the difference of the characteristic between high power IGBT modules and press pack IGBTs

Semiconductor power modules are core components of power electronics in electrified vehicles. Packaging technology often has a critical impact on module performance and reliability. This paper presents a comprehensive review of the automotive power module packaging technologies. The first part of this paper discusses the driving factors of packaging technology development. In the second section, the design considerations and a primary design process of module packaging are summarized. Besides, major packaging components, such as semiconductor dies, substrates, and die bonding, are introduced based on the conventional packaging structure. Next, technical details and innovative features of state-of-the-art automotive power modules from major suppliers and original equipment manufacturers are reviewed. Most of these modules have been applied in commercial vehicles. In the fourth part, the system integration concept, printed circuit board embedded packaging, three-dimensional packaging, press pack packaging, and advanced materials are categorized as promising trends for automotive applications. The advantages and drawbacks of these trends are discussed, and it is concluded that a preferable overall performance could be achieved by combining multiple technologies.

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Automotive Power Module Packaging: Current Status and Future Trends

This paper gives a detailed analysis on the assembly and packaging technologies for the state-of-the-art GaN-based high-electron-mobility transistors, which are suitable for high-temperature and high-power applications. Silver sintering and transient liquid phase bonding were selected as die-attachment techniques, and gold and palladium were investigated for electrical interconnection materials. Both the die-attachments were characterized for their high-temperature stability up to 450 °C. Systematic electrical characterizations were performed from on-wafer measurements to the final assembly. The thermal and thermomechanical influences of the assembly were assessed. For die-attachments and interconnections, passive temperature shock cycling and active power cycling were performed as an initial attempt to characterize the assembly reliability. Finally, a complete package along with the base plate was proposed, which can survive high temperatures up to 480 °C.

Assembly and Packaging Technologies for High-Temperature and High-Power GaN Devices

This article focuses on failure modes and lifetime testing of IGBT modules being one of the most vulnerable components in power electronic converters. IGBT modules have already located themselves in the heart of many critical applications, such as automotive, aerospace, transportation, and energy. They are required to work under harsh operational and environmental conditions for extended target lifetime that may reach 30 to 40 years in some applications. Therefore, addressing the reliability of IGBT modules is of paramount importance. The paper provides a comprehensive review on IGBT modules dominant failure modes, and long-term reliability. A detailed discussion on accelerated testing, and lifetime and degradation characterization considering thermo-mechanical stress is also presented in details.

A Review on IGBT Module Failure Modes and Lifetime Testing

Higher operation temperatures and the current density increase of new IGBT generations make it more and more complicated to meet the quality requirements for power electronic modules. Especially the increasing heat dissipation inside the silicon leads to maximum operation temperatures of nearly 200 deg C. As a result new packaging technologies are needed to face the demands of power modules in the future. In case of the chip-to-substrate interconnect basically two technology trends for an improved die attach procedure became visible. On the one hand diffusion bonding has been presented, where the joint is formed from high melting intermetallics. On the other hand the chip-to-substrate interconnect can be realized by sintering silver particles, resulting in a monometallic porous die attach layer. This paper presents a comparison of these two technology trends with respect to their applicability for power electronics packaging.

New assembly and interconnect technologies for power modules

Aging of new Interconnect-Technologies of Power-Modules during Power-Cycling

To meet the requirements of Infineon's 5th generation IGBT and diode, the .XT technology has been introduced [1,2]. It comprises a set of new packaging technologies - namely Cu wire bonding, diffusion soldering or silver sintering and soldering with strengthened Sn-based alloys. These technologies address all reliability relevant levels within the power module package in order to realize high lifetimes under thermo-mechanical stress. To explore the technology's full potential, active and passive thermal cycling test data were correlated with the responsible failure mechanisms. Thereby, a shift of the major damage location from the near-to-die interconnects towards the more distant interconnect layers (i.e., substrate and substrate solder joint) was observed. At the same time, by using .XT technologies it was possible to almost completely suppress bond wire lift-off and die attach degradation.

L. Boewer

Papers

New assembly and interconnect technologies for power modules

Aging of new Interconnect-Technologies of Power-Modules during Power-Cycling

End-of-life investigation on the .XT interconnect technology