Thermodynamic analysis of TCV interconnect structure with recast layers and rough interfaces for high-power device packaging

The thermomechanical behavior of through ceramic via (TCV) interconnect structure significantly influences the three-dimensional package reliability. However, existing studies have largely overlooked the pivotal role of defects induced by laser drilling—specifically recast layers and rough interfaces—on the regulation of thermal stresses in high-power devices. In this work, a novel thermodynamic analysis of TCV interconnect structure incorporating the recast layers and rough interfaces was proposed. A ceramic-recast layer-copper model with tunable interface roughness was established employing the Weierstrass-Mandelbrot (W-M) fractal function. The experimental results agree well with the simulation results, with a maximum error of only 11.1%. The thermodynamic simulation results reveal a nonmonotonic relationship between thermal stress and interfacial roughness: thermal stress first decreases, reaching a minimum at 0.2 μm roughness across all temperatures (200 ~ 500°C), before increasing with additional roughness. Thermal deformation decreases slightly with increasing roughness. Further analyses demonstrate that the aforementioned laws are consistent both with and without a recast layer and across varying TCV aspect ratios (AR = 3.13 ~ 8.33), thereby substantiating the model’s universality. This study establishes quantitative correlations between process-induced defects and thermomechanical performance, offering insights for optimizing laser drilling parameters and TCV structural designs in high-density 3D packaging applications.