Research on the protrusion behavior and evolution mechanism of TSV in 3D packaging under high temperature

Purpose 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. Design/methodology/approach 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. Findings 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. Originality/value 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.