This paper aims to investigate the protrusion behavior of Cu-filled through-silicon via (TSV) in 3D packaging under high-temperature conditions and to clarify the dominant physical mechanisms governing the evolution of TSV protrusion during long-term thermal exposure.
High-temperature annealing experiments were carried out on TSV samples at 400 °C for different holding times. The protrusion behavior was characterized using atomic force microscope, SEM, focused ion beam and electron backscatter diffraction. In parallel, a finite element model incorporating elastoplastic deformation and diffusion creep was constructed to simulate TSV-Cu protrusion, and the simulation results were validated against experimental measurements.
Experimental results show that TSV-Cu exhibits significant axial protrusion under high-temperature storage, with protrusion height increasing continuously with holding time. Finite element analysis indicates that TSV protrusion is caused by the combined effects of plastic deformation during heating and time-dependent creep deformation during high-temperature holding. The coupled plastic–creep model shows good agreement with experimental results in both trend and magnitude.
This paper proposes an experimental–numerical framework that explicitly couples plastic deformation and diffusion creep to describe TSV-Cu protrusion. The validated model offers a more comprehensive and physically accurate understanding of protrusion evolution under high-temperature conditions, providing valuable insight for the reliability design of 3D-integrated packaging.
