Residual stress and thermally induced warpage are critical reliability concerns in power electronic packaging, particularly when employing sintered copper nanoparticle (Cu NP) interconnects. While these interconnects provide high thermal and electrical performance, they also introduce significant interfacial stresses during bonding that alter mechanical behavior during service. This study develops an integrated confocal Raman–analytical modeling framework to directly quantify and mechanistically interpret these stresses in a representative SiC/Sintered Cu NPs/Active Metal Brazing ceramic substrate (AMB) stack. Raman spectroscopy reveals a compressive interfacial stress field peaking at −334 MPa near the chip center with localized hotspots linked to microporosity. Complementary in-situ Moiré interferometry tracked warpage evolution during thermal cycle (30–310°C). Coupling this stress measurement with a three-dimensional thermoelastic model, and explicitly assigning the bonding temperature as the stress-free reference, enables accurate reproduction of the temperature-dependent warpage trajectory. The model predictions align with experimental interferometry within < 5% deviation. These results demonstrate that incorporating residual stress is essential to realistically capture thermo-mechanical evolution. The proposed Raman–model paradigm advances beyond prior purely numerical or purely experimental efforts by bridging quantitative stress mapping with predictive warpage modeling. This methodology provides essential insights for thermal-induced residual stress and warpage managements in high-temperature power electronics packaging, providing a stress-informed foundation for reliability assessment and design optimization.

Reducing parasitic parameters and thermal resistance is critical for advancing power electronic devices. This article designs and evaluates the three printed circuit board (PCB) embedded 1200 V SiC mosfet half-bridge packaging cells, where the traditional wire bonding process is replaced by a redistribution layer (RDL) technique. A comprehensive evaluation of their electrical performance, thermal management, and mechanical performance is conducted. The three solutions that employ panel, active metal brazing (AMB), and lead—frame carriers, are developed through a streamlined process that includes die attach, molding, drilling, plating, and etching. This packaging approach readily reduces the parasitic inductance to below 5 nH. By utilizing a single-layer RDL with mutual inductance cancellation, the power loop inductance is reduced to as low as 2.4 nH (at 10 MHz), and the gate loop inductance to 1.57 nH (at 10 MHz). The junction-to-case thermal resistances of the three solutions are 1.88, 1.03, and 0.73 K/W, respectively. Compared with the other two packaging cells, the cell selecting AMB as a carrier reduces SiC mosfet operational stress and deformation by approximately 34% and 75%. The lead—frame carrier offers superior thermal dissipation for potential TO package replacement in half-bridge topologies, while the panel solution is promising for dual-sided cooling applications. With low thermal resistance, minimal stress, and excellent backside electrical insulation, the packaging cell with an AMB carrier is ideally suited for integration with heatsinks in traction inverters.

Sintered nano-copper (Cu) improves the thermal performance of SiC MOSFET Fan-Out Panel-Level Packaging (FOPLP), a widely adopted method for miniaturizing electronic systems and modules. This study presented, for the first time, the prototyping and characterization of a 1.2 kV SiC MOSFET FOPLP half-bridge power module using sintered nano-Cu die attachment (FOPLPCu), and compared it with a reference module using conductive Ag adhesive interconnects (FOPLP_Ag). Thermal, mechanical, and electrical co-simulations proved that FOPLPCu exhibited superior performances with lower thermal resistance, power loop parasitic inductance, and thermal deformation, achieving values of 0.14 °C/W (with double-sided cooling), 3.15 nH (@100 kHz), and 9.05e-5 m, respectively. In contrast, FOPLP_Ag showed higher values of 0.24 °C/W, 3.27 nH, and 1.04e-4 m. It is worth noting that due to the higher elastic modulus of sintered nano Cu, FOPLPCu experienced increased thermal stress. The internal structure analysis of the packaged devices, conducted using CSAM, showed that both FOPLPCu and FOPLP_Ag had well-formed interconnections, with no signs of delamination in the EMC, RDL, or interconnect layers. Thermal testing showed that FOPLPCu achieved a single-side thermal resistance of 1.95 °C/W, representing a 22% improvement compared to FOPLP_Ag's 2.5 °C/W. Electrical testing further demonstrated that FOPLPCu had lower on-state resistance compared to FOPLP_Ag, while maintaining comparable breakdown voltage, threshold voltage, and body diode forward voltage drop.

Power electronics devices, pivotal in advancing electronic system technology, are essential for energy saving, enhancing power control efficiency, reducing noise, and minimizing size and volume. The evolution of power modules is based on innovative packaging structures, technologies, and materials. This article provides a comprehensive review of inorganic nonmetallic packaging materials and technologies in power electronics packaging. It first analyzes the packaging structures and trends of power electronics. The article then discusses inorganic nonmetallic encapsulants such as cement and glass in detail. It also reviews traditional ceramic substrates and elaborates on the advantages of multilayer ceramic technologies, including low-temperature co-fired ceramics, as substrates, while looking forward to the commercialization of inorganic composite substrates such as SiCp/Al matrix composites and diamond. Subsequently, the article overviews inorganic nonmetallic fillers for thermal interface materials, emphasizing the application of two-dimensional materials such as graphene and boron nitride, and introduces inorganic nonmetallic phase change materials. Finally, it explores the application and future development trends of inorganic nonmetallic materials in embedded packaging technologies.

Accurate characterization and calculation of the interfacial stresses are of key importance for the optimization of the chip sintering process and the evaluation of the long-term reliability of the chip interconnect. In this study, the pioneering application of confocal Raman spectroscopy for the accurate, rapid, and nondestructive characterization of interfacial stresses at the interconnections of silicon carbide chips was undertaken. Silicon carbide chips (5 mm ∗ 5 mm) were mounted to active metal brazing substrates by pressure-assisted sintering using copper nanoparticles. Subsequently, finite element simulations were used to model the thermally induced deformation and stress in the SiC chip. The thermally induced warpage of the SiC chip was then measured using interferometry. Finally, confocal Raman spectroscopy was employed to measure the interface stress distribution at the SiC sintered copper interface. The results showed that finite element simulations could not accurately assess the thermally induced deformation and stress in the SiC chip. The proposed method based on confocal Raman spectroscopy for testing chip interconnection interface stresses achieved an excellent balance between accuracy, non-contact measurement, and non-destructive testing. The residual stress at the backside interface of the SiC chip was concentrated in the central region of the chip, with compressive stress values ranging from -139 MPa to -165 MPa. Theoretically, this study provides a new framework for modeling and researching the reliability of electronic packaging interfaces.

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.

This study investigates the size-dependent mechanical behavior and deformation mechanisms of sintered copper (Cu) nanoparticles (NPs) through micro-pillar (2–6 μm diameter) compression tests, scanning electron microscopy (SEM), transmission electron microscopy (TEM), transmission Kikuchi diffraction (TKD) analysis and molecular dynamics (MD) simulations. In-situ micro-pillar compression tests reveal a 25.9% reduction in yield strength (812 ± 64 MPa to 643 ± 47 MPa) with increasing pillar size, attributed to dislocation starvation in smaller pillars and porosity-driven strain localization in larger ones. TKD quantifies dynamic grain refinement (24.9% reduction in grain size) and geometrically necessary dislocation (GND) density escalation (74.8%), driven by stress gradients and grain boundary-mediated plasticity. Nanoindentation-derived elastic modulus (48.3 ± 11.1 GPa) exceeds micropillar values (29.5–33.9 GPa), reflecting substrate constraints in bulk testing. Microstructural analysis identifies a transition from shear banding in high-porosity pillars to uniform plasticity in denser systems, mediated by texture evolution (Brass/S components) and Schmid factor redistribution (62% increase in high-slip-activity grains). MD simulations of pressure-sintered Cu NPs elucidate atomic-scale mechanisms: dislocation nucleation at sintering necks, pore collapse-induced strain localization, and grain boundary sliding. These findings establish a multiscale framework linking porosity, grain refinement, and dislocation dynamics to mechanical performance, emphasizing microstructural optimization for enhanced reliability in microelectronic applications. The integration of MD simulations bridges atomic-scale mechanisms to microscale deformation, providing actionable insights for tailoring sintered Cu NPs via reduced porosity and controlled grain boundary architectures.