With the rapid advancement of power semiconductor packaging technologies, Smart P2 Packagingaging has emerged as a pivotal innovation for enhancing system performance and miniaturization. This study systematically investigates the thermal conduction characteristics and stress distributions of copper-filled vias (CFVs) in Smart P2Pack frontal interconnects through coupled thermal-mechanical finite element analysis. Results indicate that increasing CFV diameter enhances vertical heat conduction but causes localized heat accumulation and stress concentration due to the low thermal conductivity of encapsulation materials, elevating interfacial failure risks. Conversely, expanding CFV pitch promotes dispersed heat flow and reduces chip temperature but concurrently lowers local structural stiffness and exacerbates stress concentration. Optimal CFV design thus requires balancing thermal diffusion performance and mechanical constraints to ensure structural reliability and thermal stability.

Nano-copper (nano-Cu) sintering is a promising lead-free interconnection technology for advanced electronic packaging due to its high electrical conductivity. However, practical applications are hindered by oxidation and limited sintering efficiency. Carbon nanotube (CNT) doping has been proposed to modify sintering behavior by influencing diffusion and interfacial interactions. In this study, molecular dynamics (MD) simulations and experiments were combined to investigate the effects of CNT doping on nano-Cu sintering and interconnection performance.Two MD models were constructed: a Cu NP–CNT dual-particle model to examine interfacial interactions, and a multi-particle model to evaluate overall sintering dynamics. Results show that Cu nanoparticle size significantly affects sintering, with 4 nm particles exhibiting optimal energy reduction at 500 K, while 2 nm particles show stronger bonding at 700 K due to partial melting. CNT doping in the multi-particle system increased defect density, improving bonding strength but compromising electrical and thermal conductivity.Experimentally, nano-Cu pastes doped with various CNT types and contents were tested. A 1 wt% CNT addition enhanced shear strength, while higher contents led to agglomeration, reduced uniformity, and degraded electrical performance. SEM revealed CNT accumulation at sintering necks, and XPS indicated potential interfacial reactions involving functional groups on CNTs.Overall, CNTs play a dual role in nano-Cu sintering—enhancing mechanical performance via defect formation but reducing conductivity due to interfacial resistance. Optimizing CNT surface chemistry and dispersion is essential to balance mechanical and electrical properties in future interconnect applications.