Although silver sintering is widely used in die attach, its reliability under low-pressure and pressureless sintering conditions remains a challenge, and the degradation mechanism needs to be addressed urgently. This study investigates the degradation mechanisms of silver sintered die attach subjected to thermal shock (TS) (−45 °C to 125 °C), revealing its microstructural evolution, degradation of mechanical properties, and pore dynamics. After 1500 cycles, the average porosity did not decrease and remained at approximately 10%, but the porosity distribution exhibited significant heterogeneity, forming three characteristic regions of high porosity, low porosity, and crack regions. With the porosity evolution, the grain size increased by a factor of 2.1–2.8, with the largest grain sizes in the crack region, and the recrystallization fraction decreased significantly, from 89.6 % to a range of 37.3 %–72.1 %. Additionally, the combination with the decrease in both statistically stored dislocation density and total dislocation density reveals a decline in hardness and yield strength of silver sintered layer from 1.05 GPa and 326 MPa to 0.92 GPa and 231 MPa, respectively, gradually diminishing their ability to impede pore migration and merging. Thermal-mechanical coupling simulations based on the actual porous structure images show that the mismatch in the coefficient of thermal expansion induces alternating tensile and compressive thermal stresses, driving pore evolution and crack propagation. The kinetic Monte Carlo (KMC) Potts model based on Kawasaki dynamics combined with pore conservation can effectively predict the long-term pore evolution in this case. These findings provide important guidance for optimizing the sintering process and improving the application of silver sintering materials in high-reliability electronic packaging.

With the rapid development of new energy vehicles and offshore wind power systems in coastal cities, the application scale of power devices is constantly increasing. However, the corrosion problem of power packaging interconnection materials caused by the humid air and chlorine-rich environment near the sea is gradually emerging. This study addresses the corrosion protection of sintered nano-copper by innovatively employing atmospheric pressure plasma jet (APPJ) technology with hexamethyldisiloxane (HMDSO) as precursor to construct organic-inorganic hybrid hydrophobic coatings on copper surfaces. Experimental results demonstrate that the coating exhibits a three-dimensional crosslinked Si-O network structure. The synergistic effect between surface micron-scale spherical clusters and methyl groups elevates the contact angle by 50 % to 153.1° Electrochemical characterization reveals that the coating positively shifts corrosion potential by 0.035 V and reduces corrosion current density from 6.008×10−7 A/cm2 to 5.542×10−7 A/cm2, while maintaining higher activation energy across the experimental temperature range (30–60℃). EIS tests show that the coating effectively increases the charge transfer impedance of the sample, indicating an improvement in corrosion resistance. The 168-hour immersion test confirms effective barrier against Cl−corrosive attack with preserved substrate integrity. Density functional theory (DFT) simulations elucidate that unsaturated methylated fragments in HMDSO preferentially graft onto copper surface via chemisorption, where strong interfacial bonding energies (-2.26 ∼ -4.38 eV) facilitate cleavage and crosslinking to form stable siloxane networks. This work proposes a novel anti-corrosion surface engineering strategy for copper interconnects, while revealing the plasma-induced interfacial bonding mechanisms of hybrid coatings, providing both theoretical and experimental foundations for developing durable electronic packaging materials.

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.

In harsh offshore environments, large-area sintered nano-copper (Cu) interconnections, which serve as die attachment material or thermal interface material (TIM), are prone to degradation from hydrogen sulfide (H2S) corrosion. This study introduced a film-forming technique based on atmospheric pressure plasma jet (APPJ) to improve the corrosion resistance of large-area sintered nanoCu joint. The corrosion protection mechanism against H2S-containing atmospheric corrosion was investigated using both experimental methods and density functional theory (DFT) simulations. The key findings were as follows: (1) The deposition film, primarily composed of a Si-O3 network, effectively protected sintered Cu plate from corrosion by H2S gas, and maintaining the mechanical performance of sintered Cu joint after 384 h of H2S testing. (2) The dissociation products of the APPJ-treated precursor hexamethyldisiloxane (HMDSO), −OSiCH3 and −OSi(CH3)3, formed stable chemical bonds on the sintered nanoCu surface, resulting in the formation of −OSiCH3(O-CH3)2 fragments. (3) The −OSiCH3(O-CH3)2 fragments were unreactive toward to corrosion agents such as H2S, O2, and H2O, and also serving as a barrier to block their access to the sintered nanoCu surface. This study provided a comprehensive understanding of the corrosion protection mechanism of sintered nanoCu using APPJ-deposited films, offering valuable insights for improving the reliability of power electronics.

In the rapidly evolving era of information and intelligence,microelectronic devices are pivotal across various fields, such as mobile devices, big data computing, electric vehicles, and aerospace. However, the electrical performance of these devices often suffers due to residual stress from microelectronic manufacturing. This issue is compounded by the additional thermal stress that accumulates during device operation. Therefore, it is essential to understand, characterize, and control this residual stress to ensure the reliability and efficiency of microelectronic devices. Raman spectroscopy emerges as an invaluable tool for nondestructive, fast, noncontact, and precise testing of micro-scale mechanics, significantly aiding in stress and strain analysis within microelectronic manufacturing. This article aims to provide a thorough overview of the theory and application beyond a mere compilation of recent advances. Theoretically, it critically evaluates existing models that describe the Raman-stress relation. Practically, it explores the application of Raman spectroscopy in researching residual stress in various components, including substrate materials, epitaxial films, and packaging. Through a detailed examination of current applications, it highlights the significance of Raman spectroscopy in understanding micro-scale mechanics. Finally, it offers both theoretical and practical insights into the future developments of Raman-stress detection technology.

Sintered nanocopper (nanoCu) paste, exhibiting excellent electrical, thermal, and mechanical performances, offers promise for interconnections in wide bandgap (WBG) semiconductors operating at higher temperatures. However, sintered nanoCu is prone to severe corrosion in environments containing H2S, with on-site characterization methods for the composition of corrosion products currently lacking. In this study, a novel method was proposed for the rapid characterization of corrosion products during the corrosion process based on hyperspectral imaging (HSI) technology. Sintered nanoCu samples were subjected to 336 h H2S gas corrosion tests with bulk Cu as the reference, followed by correlating the corrosion element content with hyperspectral characteristic parameters. Then, the morphology and composition of corrosion products were researched using focused ion beam scanning electron microscope (FIB-SEM) and transmission electron microscope (TEM) analysis. The results showed that (1) during the corrosion process, a linear relationship was established between the Cu, O elemental atomic contents on the sample surfaces and their hyperspectral characteristic parameters. (2) The elemental atomic content of S exhibited an exponential relationship with the characteristic parameter. (3) The change rate in the spectral characteristic parameters during the corrosion process reflected the severity of corrosion, which was confirmed by comparing the thickness of the corrosion products of the sintered nanoCu and bulk Cu. This study offers a foundation for the further investigation of rapid on-site characterization of sintered nanoCu corrosion involving H2S.