Substrate-Influenced Thermo-Mechanical Fatigue of Copper Metallizations: Limits of Stoney's equation

Stephan Bigl, Stefan Wurster, Megan J. Cordill, Daniel Kiener

Research output: Contribution to journalArticleResearchpeer-review

3 Citations (Scopus)


Rapid progress in the reduction of substrate thickness for silicon-based microelectronics leads to a significant reduction of the device bending stiffness and the need to address its implication for the thermo-mechanical fatigue behavior of metallization layers. Results on 5 µm thick Cu films reveal a strong substrate thickness-dependent microstructural evolution. Substrates with hs = 323 and 220 µm showed that the Cu microstructure exhibits accelerated grain growth and surface roughening. Moreover, curvature-strain data indicates that Stoney’s simplified curvature-stress relation is not valid for thin substrates with regard to the expected strains, but can be addressed using more sophisticated plate bending theories.
Original languageEnglish
Article number1287
Number of pages8
Issue number11
Publication statusPublished - 9 Nov 2017


  • Stress
  • Thermo-mechanical
  • Thin films

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