Tomohito Iwashige

Nitto (Japan)

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Kazuhiko Sugiura

University of Occupational and Environmental Health Japan

Chuantong Chen

Osaka Research Institute of Industrial Science and Technology

Shijo Nagao

The University of Tokyo

Katsuaki Suganuma

Osaka University

Kazuhiro Tsuruta

Mirion Technologies (France)

Tohru Sugahara

Kyoto Institute of Technology

Hao Zhang

Jiangsu University of Science and Technology

Yuichi Sakuma

Prefectural University of Hiroshima

Yukinori Oda

Nomura Research Institute

Seigo Kurosaka

Nomura Research Institute

Cooperative Institutions

Osaka University

Osaka Research Institute of Industrial Science and Technology

Nitto (Japan)

Denso (Japan)

Kyoto University

Kyoto Katsura Hospital

The University of Tokyo

Denso (United States)

Industrial Research Institute of Ishikawa

Keio University

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Effect of W content in Co-W-P metallization on both oxidation resistance and resin adhesion

Journal of Materials Science (2019)

Tomohito Iwashige Takeshi Endo Kazuhiko Sugiura Kazuhiro Tsuruta Yuichi Sakuma

10.1007/s10853-019-04028-z

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Citations (3)

Reliability Evaluation of SiC Power Module With Sintered Ag Die Attach and Stress-Relaxation Structure

IEEE Transactions on Components Packaging and Manufacturing Technology (2019)

Kazuhiko Sugiura Tomohito Iwashige Kazuhiro Tsuruta Chuantong Chen Shijo Nagao

Silicon carbide (SiC) power modules with Ag sinter-bonding die attach were designed on the basis of thermal stress analysis for reliable high-temperature operations. Both the finite-element analysis (FEA) simulations and preliminary experiments confirmed that inserting the direct-bonded-copper (DBC) substrates can effectively reduce the maximum thermal stress in the module. A prototype SiC power module using sintered Ag die attach with a DBC substrate was designed and fabricated. The modules exhibited excellent durability in power cycling between 65 °C and 250 °C up to 20 000 cycles. FEA calculations of cumulative thermal strain and stress distributions adequately predicted the initial cracking position in the specimens after prolonged power cycles, observed by scanning electron microscopy.

dBc

Temperature cycling

Stress relaxation

Power module

10.1109/tcpmt.2019.2901543

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Citations (53)

In situ TEM observation of sintered Ag die-attach layer with added tungsten carbide particles while heating to high temperature

Japanese Journal of Applied Physics (2019)

Kazuhiko Sugiura Tomohito Iwashige Kazuhiro Tsuruta Chuantong Chen Shijo Nagao

We carried out in situ transmission electron microscopy (TEM) on the microstructural change of a sintered Ag die-attach layer heated to 600 °C. It was found that the addition of 2 wt% tungsten carbide (WC) particles to the sintered Ag layer significantly suppressed the microporous structure growth at elevated temperature. In the case of a pure Ag layer without anything added, microporous structure growth started from 450 °C. However, microporous structure growth was hardly observed in the sintered Ag layer with WC added up to 600 °C.

Tungsten Carbide

10.7567/1347-4065/ab42d2

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Citations (2)

Synthesis and Catalytic Performance of Organic–Inorganic Hybrid Mesoporous Material Having Basic Nanospace

Catalysis Letters (2010)

Tetsuya Shishido Toru Kawaguchi Tomohito Iwashige Kentaro Teramura Yutaka Hitomi

Aldol condensation

Aldol reaction

10.1007/s10562-010-0456-3

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Citations (5)

CoW metallization for high strength bonding to both sintered Ag joints and encapsulation resins

Journal of Materials Science Materials in Electronics (2019)

Tomohito Iwashige Takeshi Endo Kazuhiko Sugiura Kazuhiro Tsuruta Yuichi Sakuma

Encapsulation

10.1007/s10854-019-01458-y

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Citations (9)

Mechanical Deformation of Sintered Porous Ag Die Attach at High Temperature and Its Size Effect for Wide-Bandgap Power Device Design

Journal of Electronic Materials (2016)

Chuantong Chen Shijo Nagao Hao Zhang Jinting Jiu Tohru Sugahara

Solid-state physics

10.1007/s11664-016-5200-3

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Citations (80)

Metallization technology of SiC power module in high temperature operation

Tomohito Iwashige Kazuhiko Sugiura Takeshi Endo Kazuhiko Tsuruta Yuichi Sakuma

We investigated a new metallization layer has both functions in high temperature reliability with Ag sinter joining and in high temperature adhesion with insulating resin. As a result, it was found that CoW metallization layer works effectively from above two perspectives. Initial shear strength of sintered Ag joints on CoW plated layer was about 46 MPa, which is better joint strength than that of Au or Ag plated layer. Furthermore, the shear strength of insulating resin on a CoW plated layer was about 21 MPa at 225 °C, which is almost the same adhesion strength as that of Ni or Ni/Au plated layer.

Shear Strength

10.23919/icep.2018.8374326

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Citations (1)

First failure point of a SiC power module with sintered Ag die-attach on reliability tests

2022 International Conference on Electronics Packaging (ICEP) (2017)

Kazuhiko Sugiura Tomohito Iwashige Kazuhiro Tsuruta Chuantong Chen Shijo Nagao

We have investigated finite element method (FEM) modeling of thermal stress analysis in a SiC power module using sintering Ag die-attach, and explored the reliability focusing on the initial cracking point caused by the thermal stress. The analysis results by FEM models support our experimental observations in the reliability tests of the fabricated modules, confirming that using direct-bonded-copper (DBC) as a module substrate effectively reduces the thermal stress. Such an FEM analysis is thus useful for designing power modules to assure their sufficient reliability in harsh environments expected for automotive applications.

Power module

dBc

10.23919/icep.2017.7939333

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Citations (7)

Low-Stress Design for SiC Power Modules with Sintered Porous Ag Interconnection

Chuantong Chen Shijo Nagao Hao Zhang Tohru Sugahara Katsuaki Suganuma

The mechanical properties of sintered porous Ag-paste are investigated by tension test and shear test in the temperature range from 25 °C to 300°C. Stress-strain curves of sintered porous Ag-paste are measured at different temperatures. The Poisson's ratio, which is calculated by Young's modulus and shear modulus, decreased from 0.31 at 25 °C to 0.11 at 300 °C. In addition, 3D finite element model (FEM) is constructed for six types of module structures under thermal cycling analysis, which focuses particularly on the stress of sintered porous Ag-paste at different temperatures to find an optimized low-stress structure for the long-term reliability. The obtained results in this study suggested that the sintered porous Ag-paste may survive longer and continue to functions at high temperature variations because of the large plastic deformation.

Temperature cycling

Atmospheric temperature range

Shear modulus

Tension (geology)

10.1109/ectc.2016.59

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Citations (10)

High-temperature reliability of sintered microporous Ag on electroplated Ag, Au, and sputtered Ag metallization substrates

Journal of Materials Science Materials in Electronics (2017)

Chuantong Chen Katsuaki Suganuma Tomohito Iwashige Kazuhiko Sugiura Kazuhiro Tsuruta

10.1007/s10854-017-8087-8

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Citations (90)