Unravelling Cu₆Sn₅ precipitate coarsening mechanisms in SAC solders under thermomechanical cycling.

ABSTRACT: Thermo-mechanical cycling of microelectronic devices creates complex stress-states in Sn-Ag-Cu (SAC) solder balls, leading to Cu₆Sn₅-precipitate coarsening. Two key mechanisms - strain-induced coarsening and Ostwald ripening - are examined separately. Strain-induced coarsening, studied via plastic shear deformation, is more significant in dynamically recrystallised high-strain regions than in lower-strain shear band regions. Ostwald ripening is investigated via in-situ FESEM, and its interplay with strain-enhanced coarsening is analysed in thermo-mechanically cycled solders with varying Bi-contents. Results show that Bi, solved in the β-Sn matrix, delays dynamic recrystallisation and reduces both strain-enhanced coarsening and Ostwald ripening of Cu₆Sn₅. Nonetheless, Cu₆Sn₅

SUBMITTER: Cui C 

PROVIDER: S-EPMC12569173 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature