A Novel Multiple DBC-staked units Package to Parallel More Chips for SiC Power Module

Silicon carbide(SiC) power modules play an essential role in the electric vehicle drive system. To improve their performance, reduce their size, and increase production efficiency, this paper proposes a multiple staked direct bonded copper(DBC) unit based power module packaging method to parallel more chips. This method utilizes mutual inductance cancellation effect to reduce parasitic inductance. Because the conduction area in the new package is doubled, the overall area of power module can be reduced. Entire power module is divided into smaller units to enhance manufacture yield, and improve design freedom. This paper provides a detailed design, analysis and fabrication procedure for the proposed package structure. Additionally, this paper offers several feasible solutions for the connection between power terminals and DBC untis. With the structure, 18dies were paralleled for each phase-leg in a econodual size power module. Both simulation and double pulse test results demonstrate that, compared to conventional layouts, the proposed package method has 74.8% smaller parasitic inductance and 34.9% lower footprint.

Review of Hybrid Packaging Methods for Power Modules

The hybrid structure of a power-module package is summarized and classified.Basic and extended planar wire-bond designs are analyzed and compared with regular wire-bond modules and planar modules,respectively.The automatic layout method can improve the electrical and thermal performance of hybrid structures.A state-of-the-art hybrid structure is introduced,and suggestions for alleviating the current and temperature imbalances for future designs are provided.

Simultaneously optimizing pore morphology and enhancing mechanical properties of Al-Si alloy composite foams by graphene nanosheets

The integrity and regularity of pore morphology play an important role in determining the mechanical properties of the metallic foam materials.The conventional methods on refining pore morphology are mainly focused on the optimization of fabrication techniques,however,they are usually inconvenient and complicated.Recently,incorporating nano reinforcement is considered to be a suitable way to fabricate metallic composite foams accompanied by optimized pore morphology and enhanced mechanical properties.In this work,through a facile and rapid powder metallurgy foaming method,the aluminum-silicon(Al-Si)alloy composite foams reinforced by graphene nanosheets(GNSs)are successfully fabricated.The microstructure analyses reveal that,for the Al-Si alloy foams incorporating the GNSs(GNSs/Al-Si composite foams),the pore size is transformed to be smaller,the pore size distributions become more homogeneous and the pore shape is also refined to a regular and roundish state.Meanwhile,the shape of Si precipitates is found transforming from an irregular long strip(length of~20μm,width of~5μm)to a fine particle state(diameter of~5μm).Moreover,the compressive testing results show that,the 0.4wt%GNSs/Al-Si composite foams own the optimal compression stress of 11.7±0.5 MPa,plateau stress of 10.0±1.0 MPa and energy absorption capacity of 6.8±0.7 MJ/m^(3),which have improvement of 58.1%,53.8%and 51.1%in comparison with the Al-Si alloy foams counterpart,respectively.The present findings may pave a new way for developing new generation of metallic composite foams that with stable microstructure and excellent mechanical performance.

Brief Review of Silver Sinter-bonding Processing for Packaging High-temperature Power Devices

Silver sintering is receiving increasing attention due to its novel die-attach technique for high-temperature power electronics.Excellent thermal conductivity,high melting point/remelting temperature and low-temperature sintering behaviors of the silver sintered attachment meet the requirements of high-temperature applications for power devices,specifically SiC devices.The merits and demerits of the existing pressure-assisted sintering and pressure-less sintering techniques using nano-scale,micro-scale and micro-nano-scale hybrid silver sintered materials are separately presented.The emerging rapid sintering approaches,such as the electric-assisted approach,are briefly introduced and the technical outlook is provided.In addition,the study highlights the importance of creating a brief resource guide on using the correct sintering methods.