Microscopic fracture toughness of notched porous sintered Cu micro-cantilevers for power electronics packaging

Dong Hu, Leiming Du, Markus Alfreider, Jiajie Fan, Daniel Kiener, Guoqi Zhang

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Abstract

To fulfill the high-temperature application requirement of high-power electronics packaging, Cu nanoparticle sintering technology, with benefits in low-temperature processing and high-melting point, has attracted considerable attention as a promising candidate for the die-attach interconnect. Comprehensive mechanical characterization of the sintered layer at a microscale is necessary to deepen the understanding of the fracture behavior and improve the reliable design of materials. In this study, microscale cantilevers with different notch depths were fabricated in a 20 MPa sintered interconnect layer. Continuous dynamical fracture testing of the microcantilevers was conducted in situ in a scanning electron microscope to detail the failure characteristic of the porous sintered structure. The microscopic fracture toughness of different notched specimens was obtained from the J-integral in the frame of elastic-plastic fracture mechanics. Specimens with deeper notches presented higher resistance to crack extension, while geometry factors of notch-to-width ratio between 0.20 and 0.37 exhibited a relatively stable microscopic fracture toughness ranging from 3.2 ± 0.3 to 3.6 ± 0.1 MPa m1/2.
Original languageEnglish
Article number146316
Number of pages10
JournalMaterials Science and Engineering: A
Volume897.2024
Issue numberApril
Early online date7 Apr 2024
DOIs
Publication statusPublished - 7 Apr 2024

Bibliographical note

Publisher Copyright: © 2024 The Authors

Keywords

  • Continuous stiffness testing
  • Cu nanoparticles sintering
  • Elastic-plastic fracture mechanics
  • Microscopic fracture toughness

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