Abstract No.:
7170

 Scheduled at:
Wednesday, June 22, 2022, Saal Brüssel 3:40 PM
Joining of glass, ceramics and metals


 Title:
Active metal brazed Cu-Si3N4 composites for power electronics

 Authors:
Axel Rost* / Fraunhofer IKTS, Germany

 Abstract:
For electric circuit boards, the demands of temperature stability and thermal cycling ability are increasing, not only by super charging for electromobility, but also by higher packing densities and new semiconductor materials (e.g. SiC) with increased thermal stability. Manufacturing Cu-Si3N4 composites by Direct Copper Bonding (DCB) is already well known, but in terms of thermal cycling stability very limited. Using Active Metal Brazing (AMB) processes to join Cu to Si3N4 extends the lifetime of the components by increased thermal cycle ability. Therefore, not only the joining process conditions are important, but also the quality of the to join materials Si3N4 and Cu.
In a consortium ranging from a Si3N4 powder supplier, ceramic sintering specialists, a copper producer, joining experts, furnace specialists and a manufacturer of scanning acoustic microscopes, all aspects of producing and analyzing reliable Cu-Si3N4 circuit boards are addressed. The investigation of the joining process is based on a variation of Si3N4 and Cu qualities in combination with different active filler metals and temperature regimes for joining. The composites were analyzed by non-destructive scanning acoustic microscopy to detect joining defects and tensile peel strength measurements to measure the joining strength. With field emission electron microscopy, the formation and growth of reaction layers between the filler metals and Si3N4 was analyzed in respect to the joining conditions. In correlation to the strength measurements, an evaluation of suited combinations of Cu, Si3N4 and joining conditions is presented.


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