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 degrees C to 125 degrees 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.

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.

Reliable 4H-SiC for high-power electronics and quantum photonics requires a quantitative understanding of how contact loading drives microstructure evolution and load-bearing/fracture response in epitaxial layers. Here, we integrate instrumented indentation, confocal micro-Raman residual-stress metrology, atomistic molecular dynamics (MD), and high-resolution TEM (HRTEM) to establish processing-microstructure-mechanical property linkages in chemical vapor deposition (CVD) 4H-SiC epilayers. At peak depths of 600-1050 nm, indentation promotes Palmqvist-type radial cracks and the apparent indentation toughness K-IC increases from 0.87 +/- 0.08 to 1.20 +/- 0.05 MPa m(1/2) with depth, consistent with plastic-zone growth and dislocation shielding. E-2(TO) Raman mapping quantifies an increase in residual stress from similar to 302 +/- 60 to similar to 665 +/- 72 MPa. It also shows that the incremental broadening of the FWHM becomes less pronounced beyond similar to 750 nm, suggesting that the near-surface disorder indicator within the Raman probe volume approaches a quasi-steady level. MD captures a 4H -> 3C phase transformation, amorphization beneath indenter ridges, and dislocation nucleation/growth, which HRTEM directly corroborates. The combined measurement-model-validation closed loop yields a depth-dependent relationship between residual-stress accumulation and apparent toughness, converting them into an actionable processing window: constraining penetration depth below similar to 0.75 mu m limits residual stress and near-surface disorder. These results provide physics-based guidance for machining and packaging of 4H-SiC epilayers and illustrate a transferable framework for brittle, anisotropic ceramics.

The reliability of through-glass via (TGV) interconnects is critical for advanced semiconductor packaging. This work investigates microstructural and mechanical evolution in electroplated TGV–Cu subjected to long-term aging at 250 °C. TGV samples were fabricated via laser-induced etching and double-sided copper electroplating, then aged for up to 1008 h. Nanoindentation revealed region-dependent reductions in hardness (from 2.0–2.5 GPa to below 0.5 GPa) and modulus (from 110–130 GPa to 40–90 GPa), with surface-near regions most affected. The glass substrate maintained stable mechanical properties until microcracks formed after 1008 h. EBSD quantification showed grain-size enlargement from 0.46 µm to 1.86 µm and a concurrent decrease in dislocation density. Molecular dynamics simulations of 3, 4, 5 nm grains corroborated the inverse relationship between grain size and micro-mechanical properties. A hybrid Potts-phase field model further linked grain coarsening to stress relaxation and elastic-energy minimization, revealing that as grains grow, the overall von Mises stress in the structure decreases; high-modulus grains retain relatively higher local stresses, while low-modulus, low-stress grains exhibit faster growth rates. Electrical I–V measurements confirmed stable ohmic behavior, despite a drop in insulation resistance. These integrated experimental and computational insights provide theoretical guidance for optimizing TGV interposer design and ensuring long-term operational reliability in heterogeneous integration technologies.

As 2.5D/3D advanced packaging moves toward higher interconnect density, glass substrates are attractive for their electrical performance and dimensional stability. However, high aspect ratio, fine pitch through-glass vias (TGVs) are prone to thermo-mechanical failures under long-term thermal shock, and microscale reliability assessment is hindered by costly microstructural characterization and the lack of models capturing long-term microstructural evolution and property degradation. Here, fully copper-filled TGV-Cu structures were fabricated on Schott AF32 glass and subjected to thermal-shock cycling from - 40 ℃ to 125 ℃ (0, 700, 1400, and 2100 cycles). Results show a non-monotonic, location-dependent hardness evolution with pronounced heterogeneity, where the mid-via region exhibits stronger late-stage softening by nanoindentation. EBSD shows grain diameter increases from 0.61 μm to 0.91 μm, while GND density decreases by recovery and then re-accumulates preferentially near the via bottom, evidencing competition between grain-growth softening and dislocation hardening. Hybrid Potts-phase field simulations further predict continuous grain growth and stress relaxation (declining von Mises stress) inside the via; including the glass substrate and interface constraints raises the stress level but preserves the relaxation trend. Moreover, the phase field simulations results of equivalent plastic strain (PEEQ) reveal progressively intensified cyclic plastic localization near the top/bottom caps (Cu/glass intersections), providing mechanistic support for cracking localized at the via mouths.

Investigating the interconnection and strengthening mechanisms of die-attach layers is instrumental for advancing die attach process toward low-pressure and, ultimately, pressureless sintering while maintaining reliability. This study compares the microstructure and micromechanical heterogeneity of the pressure-assisted and pressureless regions in SiC die attach to elucidate the interconnection and strengthening mechanisms. Recrystallized grains make up 71.7 % of the pressureless region, markedly lower than the approximately 90 % observed in the pressure-assisted region, resulting in a higher porosity in the former. Evidence of both continuous dynamic recrystallization and discontinuous dynamic recrystallization is identified throughout the sintered layer. Microhardness reveals that the pressureless zone exhibits a hardness of 0.373 GPa, significantly lower than left (0.745 GPa) and right (1.832 GPa) of pressure-assisted region. All three regions share an average grain size of 400 +/- 50 nm, and geometrically necessary dislocation density in pressureless zone exceeds that in pressureassisted areas, neither of which can account for the difference in micromechanical performance. In contrast, the statistically stored dislocation (SSD) densities on the left and right of the pressure-assisted region are approximately 4.74 x 1014 m- 2 and 2.88 x 1015 m- 2, respectively-substantially higher than the 2.88 x 1014 m- 2 measured in the pressureless region. Collectively, these findings demonstrate that dislocation strengthening, and particularly SSD density, constitutes the dominant strengthening mechanism in silver sintered layers. This work not only provides new insights for enhancing reliability under low-pressure and pressureless sintering but also establishes a theoretical foundation for optimizing sintering material formulations.

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.

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 degrees Electrochemical characterization reveals that the coating positively shifts corrosion potential by 0.035 V and reduces corrosion current density from 6.008x10(-7) A/cm(2) to 5.542x10(-7) A/cm(2), while maintaining higher activation energy across the experimental temperature range (30-60 degrees C). 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 similar to -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.

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 paper provides a comprehensive review of inorganic non-metallic packaging materials and technologies in power electronics packaging. It first analyzes the packaging structures and trends of power electronics. The paper then discusses inorganic non-metallic 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 (LTCC), as substrates, while looking forward to the commercialization of inorganic composite substrates such as SiCp/Al matrix composites and diamond. Subsequently, the paper overviews inorganic non-metallic fillers for thermal interface materials, emphasizing the application of 2D materials such as graphene and boron nitride (BN), and introduces inorganic non-metallic phase change materials. Finally, it explores the application and future development trends of inorganic non-metallic materials in embedded packaging technologies.

This Letter presents a combined analytical and experimental method to effectively decouple the radial and tangential residual stress fields induced by Berkovich nanoindentation in single-crystalline 4H-SiC using micro-Raman spectroscopy. By integrating the Raman stress characterization model with Yoffe’s expanding cavity model, precise extraction of individual residual stress components around the indentation region is realized. Through the vertical backscattering micro-Raman mapping of the E 2 phonon mode, we systematically investigate the residual stress distribution near the indentation. The results highlight significant anisotropy in nanoindentation-induced stress fields, strongly dependent on the crystal orientation of 4H-SiC, predominantly featuring radial tensile stress gradients. This comprehensive theoretical–experimental approach offers a robust optical framework for residual stress characterization in 4H-SiC and provides foundational insights for extending Raman spectroscopy-based stress characterization to other crystalline materials and related device structures.

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 (FOPLP_Cu), and compared it with a reference module using conductive Ag adhesive interconnects (FOPLP_Ag). Thermal, mechanical, and electrical co-simulations proved that FOPLP_Cu exhibited superior performances with lower thermal resistance, power loop parasitic inductance, and thermal deformation, achieving values of 0.14 degrees 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 degrees 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, FOPLP_Cu experienced increased thermal stress. The internal structure analysis of the packaged devices, conducted using CSAM, showed that both FOPLP_Cu and FOPLP_Ag had well-formed interconnections, with no signs of delamination in the EMC, RDL, or interconnect layers. Thermal testing showed that FOPLP_Cu achieved a single-side thermal resistance of 1.95 degrees C/W, representing a 22% improvement compared to FOPLP_Ag's 2.5 degrees C/W. Electrical testing further demonstrated that FOPLP_Cu had lower on-state resistance compared to FOPLP_Ag, while maintaining comparable breakdown voltage, threshold voltage, and body diode forward voltage drop.

Silicon carbide (SiC) power devices exhibit superior thermal conductivity and excellent high-temperature stability, making them promising for high-power applications under extreme environments. However, ensuring long-term reliability, especially for devices packaged with glass encapsulant, remains a significant challenge. This paper introduces a high-temperature step stress aging test as a highly accelerated life testing method to evaluate the reliability of SiC Schottky diodes packaged with glass encapsulants compared to traditional plastic-packaged counterparts. In this test, diodes undergo incremental thermal stress from 50 degrees C to 300 degrees C, increasing by 50 degrees C per step and held for 168 hours per step to simulate prolonged thermal exposure. Finite element simulations were also performed at 300 degrees C to analyze stress distributions in various packaging configurations. Post-aging results demonstrate the effectiveness of this accelerated method for rapidly assessing device degradation, providing valuable reliability insights for applications in extreme thermal environments such as aerospace power systems.

The high-temperature applications of Silicon Carbide (SiC) power devices are constrained by traditional epoxy molding compound (EMC). A significant challenge arises from the mismatch between the thermal expansion coefficients (CTE) of the encapsulant and the SiC chip, generating thermal and mechanical stresses during prolonged high-temperature operation. While glass encapsulants offer stability above 300 degrees C, these stresses can lead to mechanical degradation and eventual failure of SiC power devices. We design a glass-based encapsulation material to adjust the CTE of the glass to match that of the SiC chip (3-9 ppm/degrees C), enabling encapsulation of the device for long-term operation at 300 degrees C. Finite element analysis (FEA) confirms that the CTE adjustment effectively reducs internal thermal stresses. The glass composite with 10 wt% PbTiO3 3 demonstrates a Tg g of 310 degrees C and a CTE of 8.48 ppm/degrees C, successfully encapsulating a SiC schottky barrier diode in TO-247 package form. The encapsulated device exhibits low leakage current, a reverse breakdown voltage of 1,700 V, and a thermal resistance of 0.45 degrees C/W. Notably, the device maintains excellent performance even after 1,176 h of high- temperature aging, including 336 h at 300 degrees C and exhibits minimal change during thermal cycling between-50 and 150 degrees C for 100 cycles. Long-term performance analysis demonstrates superior stability compared to EMC encapsulation. These results highlight the potential of glass-based encapsulants for wide band gap power devices, offering reliability and performance under extreme conditions.

Silicon carbide (SiC) power devices are attracting significant attention due to their outstanding stability in high-voltage, high-temperature, and high-frequency environments. To replace toxic Pb-based glass, there is an urgent need to develop Pb-free glass for SiC power device encapsulation, considering its superior electrical insulation properties and processing capabilities. Here, we developed a Bi-based glass for effective encapsulation practical of SiC power devices. By increasing the content of glass modifier BaO, the structure of bismuth borate glass can be tuned to reduce glass network density, leading to the transition of structural units from [BO4] to [BO3]. The softened temperature is reduced to 363.4 degrees C with the BaO content increasing to 15 mol%. After encapsulating the SiC power devices using Bi-based glass, the glass demonstrated a reverse breakdown voltage of 650 V and an extremely low leakage current. Therefore, our work provided a route for adapting Pb-free-based low-melting glass for encapsulating SiC devices and offered potential for advanced semiconductor packaging. Glass encapsulation process flowchart for glass encapsulated SiC SBD.image

Functionalizing glass with optically active quantum dots has shown great potential in near-infrared bioimaging and optical communication. However, the size distribution of quantum dots is hard to control by traditional glass quenching method due to extremely high processing temperature (similar to 1300(degrees)C), resulting in unexpected transmission loss and luminescent quenching of quantum dots embedded in a glass composite. Herein, we developed a nanoconfined synthesis of lead sulfide (PbS) quantum dots in a mesoporous aluminosilicate glass matrix at a relatively low temperature of 600 C-degrees with adjustable near-infrared broadband luminescence. The sol-gel-synthesized glass composite precursor with high surface areas over 480 m2/g and a nanopore mean diameter of about 3.2 nm can enable the homogeneous dispersal of PbS quantum dots in the mesoporous glass matrix as well as restrict the overgrowth of quantum dots to prevent aggregation. The PbS-AS glass composites exhibited dual-band near-infrared luminescence, showcasing morphological and nonlinear saturable absorption properties. The 0.8PbS-AS glass served as an effective saturable absorber for a passively mode-locked Er-doped fiber laser, achieving a pulse repetition rate of similar to 0.09 kHz/mW and a pulse width of similar to 0.04 mu s/kHz. The PbS-SA is confirmed to be suitable for a Q-switched mode-locking laser, showing high potential for mode-locked laser generation with further SA optimization.

Eliminating surface ion contamination, increasing the reverse breakdown voltage and reducing the leakage current are extremely important for semiconductor devices. Herein, we demonstrated that regulating the valence state of lead ions in lead aluminosilicate glass can efficiently improve the performance of glass passivation technique for chip packaging. It was found that heat treatment technique can be utilized to control valence state of lead ions from +4 into +2 in 20PbO-4.8Al(2)O(3)-75.2SiO(2) (mol%) (PAS) glass powder, which induces transformation of [PbO3] units into stable glass former units of [PbO4] and generates a free state and charge compensator of Pb2+, therefore contributing to a more stable structure and discoloration of glass. As a result, the optical band gap of glass powder was enhanced from 4.1772 to 4.3184, which could significantly improve glass insulation. As a demonstration of chip packaging, PAS glass powder, after heat treatment processing into a paste for the passivation layer of metal-oxide-semiconductor (MOS) structure devices shows a tight and integrated structure and exhibits a lower fixed charge density from 3.97 x 10(10)cm(-2) to 2.73 x 10(10) cm(-2). This work provides techniques to adjust the structure of glass to enhance the passivation performance of glass for chip packaging.

Based on previous works, most of the transition metal phosphides (TMPs) were directly prepared by decomposing NaH2PO2 with the precursors at high temperatures, which resulted in different degrees of phosphidation in the final product. Therefore, it is necessary to design an innovative approach to enhance the degree of phosphidation in the material using crystal defects. Here, oxygen-vacancy iron oxide/iron foam (Ov-Fe2O3/IF) was firstly prepared by generating oxygen vacancy in situ in an iron foam through heating in vacuum conditions. Subsequently, FeP/IF was formed by phosphating Ov-Fe2O3/IF. Under the effects of oxygen vacancies, oxygen-vacancy iron oxide could be completely phosphatized to produce more active sites on the surface of the material. This, in turn, could result in a catalyst with exceptional hydrogen evolution activity. Thus, the successful fabrication of FeP/IF demonstrated in this work provides an effective and feasible way for the preparation of other high-efficiency catalysts.

A melamine-based carbon foam was obtained from a melamine foam (2×2×2 cm3), which was then coated with graphene by immersing it in 400 mL of a suspension of reduced graphene oxide in water with concentrations of 25 to 100 mg/L. MoS2/graphene/carbonized melamine foam composites for use as catalysts for the hydrogen evolution reaction were synthesized by the hydrothermal growth of MoS2 nanosheets on the graphene-coated carbon foams in a mixed solution of molybdic acid disodium salt and thiourea. Results indicate that MoS2 nanosheets with a thickness of 15–20 nm were uniformly distributed on the three-dimensional carbon foam substrates coated with different amounts of graphene. The amount of graphene coating has a great influence on the hydrogen evolution performance. The composite prepared with a graphene concentration of 25 mg/L has the best electrochemical performance, its initial overpotential at a 10 mA cm–2 current density is 163 mV, and the corresponding Tafel slope is 76 mV dec–1. It has also the lowest impedance, which shows that coating the carbon foam with an appropriate amount of reduced graphene oxide accelerates electron migration and improves the hydrogen evolution performance.

There is an urgent need for an effective and long-lasting ceramic filter for point-of-use water treatment. In this study, silver-diatomite nanocomposite ceramic filters were developed by an easy and effective method. The ceramic filters have a three-dimensional interconnected pore structure and porosity of 50.85%. Characterizations of the silver-diatomite nanocomposite ceramic filters were performed using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Silver nanoparticles were confirmed to be formed in situ in the ceramic filter. The highest silver concentration in water was 0.24 mu g/L and 2.1 mu g/L in short- and long-term experiments, indicating very low silver-release properties of silver-diatomite nanocomposite ceramic filter. The nanocomposite ceramics show strong bactericidal activity. When contact time with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) of 10(5) colony forming units (CFU)/mL exceeded 3 h, the bactericidal rates of the four different silver content ceramics against E. coli and S. aureus were all 100%. Strong bactericidal effect against E. coli with initial concentration of 10(9) CFU/mL were also observed in ceramic newly obtained and ceramic immersed in water for 270 days, demonstrating its high stability. The silver-diatomite nanocomposite ceramic filters could be a promising candidate for point-of-use water treatment.

The recent surge in applications of deuterated pharmaceutical agents has created an urgent demand for synthetic methods that efficiently generate deuterated building blocks. Here, we show that N-heterocyclic carbenes promote a reversible hydrogen–deuterium exchange reaction with simple aldehydes, which leads to a practical approach to synthetically valuable C1 deuterated aldehydes. The reactivity of the well-established N-heterocyclic carbene-catalysed formation of Breslow intermediates from aldehydes is reengineered to overcome the overwhelmingly kinetically favourable benzoin condensation reaction and achieve the critical reversibility to drive the formation of desired deuterated products when an excess of D2O is employed. Notably, this operationally simple and cost-effective protocol serves as a general and truly practical approach to all types of 1-D-aldehydes including aryl, alkyl and alkenyl aldehydes, and enables chemoselective late-stage deuterium incorporation into complex, native therapeutic agents and natural products with uniformly high levels (>95%) of deuterium incorporation for a total of 104 tested substrates. Deuterated molecules are important both as labelled probes and as targets in their own right. Here the authors report a very simple and general deuteration of aldehydes, by the use of an N-heterocyclic carbene catalyst in the presence of D2O.