Glass substrates and glass interposers are emerging as promising alternatives to organic substrates and silicon interposers in advanced IC packaging for AI, HPC, and 5G/6G applications. This is due to their tunable CTE, high stiffness, excellent electrical performance, low cost, scalability, and compatibility with fine-line RDLs. However, the intrinsic brittleness and crack susceptibility of glass materials constitute major obstacles to their widespread adoption. This study will investigate the mechanics of the through-glass-via (TGV) array in the biaxial bending ring-on-ring (RoR) test using theoretical and numerical stress analyses, and then experimentally determine the bending strength of TGV glass substrates with and without the etching process. The experimentally obtained bending strengths are analyzed and discussed in relation to the corresponding failure modes and underlying mechanical behavior.
As electronic systems demand ever higher levels of integration, fan-out (FO) packaging has become essential for enabling high input/output (I/O) density, miniaturization, and heterogeneous integration. Although wafer- and panel-level FO architectures offer enhanced scalability and cost-effectiveness for large-area manufacturing, the literature contains little information on balancing fine-line redistribution layer (RDL) designs with the need for mechanical stability and long-term reliability under thermomechanical stress. To address this problem, this study presents a strip-level fan-out (FO-Strip) package featuring a die-last architecture that facilitates superior RDL definition with a line/space resolution of 5 μm/5 μm. With a fan-out region of 36.5 mm × 29.5 mm and a substrate measuring 50 mm × 50 mm, the proposed package design combines the scalability advantages of panel-level production with enhanced manufacturability and cost effectiveness. To enable systematic multi-parameter design optimization, a three-dimensional finite element (FE) model is developed to simulate the thermomechanical response of the package during assembly and JEDEC-standard thermal cycling at −40°C to 125°C. The simulation results for the out-of-plane warpage are shown to be consistent with the experimental data obtained from shadow Moiré measurements. A response surface methodology (RSM) technique with a Box–Wilson central composite design is applied to examine the effects of the die thickness, heat sink thickness, and thermomechanical properties of the encapsulant (EMC), substrate core, and underfill material on the warpage and plastic work accumulation during thermal loading. The results show that increasing the die and heat sink thicknesses and optimizing material properties (reducing the CTE mismatch between the FO package and the substrate) reduce package warpage by 41.4% and solder joint plastic work density by 53.4%. Overall, the proposed design and optimization framework provides useful practical guidelines for improving the thermomechanical reliability of large-area fan-out packages and establishes a predictive platform for next-generation heterogeneous integration applications.
Silver indium phosphorous sulfide (AgInP2S6), an important member of quaternary transition metal phosphorous trichalcogenides (TMPTs), has recently arrested widespread attention in potential applications, yet its high-pressure physicochemical characteristics remain scarcely elucidated. In this paper, the high-pressure structural, vibrational and electrical transport properties of AgInP2S6 are comprehensively investigated at pressure up to 55.4 GPa using both experimental determinations and ab initio calculations. AgInP2S6 undergoes two isostructural phase transitions (IPTs) at the respective pressures of 10.3 and 22.6 GPa under non-hydrostatic condition triggered by the prominent shrinkage of interlayer distance and the twist or rotation of P-P bonds, which was well supported by the notable discontinuities in the calculated lattice constant ratio (a/c). Further compression to 40.2 GPa, the semiconductor-to-metal transition occurs, which was confirmed by the positive-to-negative sign reversal in the temperature-dependent electrical conductivity relations. On application of hydrostatic compression, the IPTs and metallization are delayed by approximately 2.0 and 4.0 GPa owing to the influence of deviatoric stress. Upon decompression, the phase transitions are revealed to be reversible with the presence of giant pressure lagging under different hydrostatic environments. These combined experimental and computational results on AgInP2S6 advance our understanding of the physicochemical behaviors of TMPTs under extreme conditions, and thus laying a solid foundation for its future development in multifunctional devices.
Ultraviolet (UV) irradiation is an unavoidable environmental factor for electronic devices. To investigate the effects of UV irradiation on MgSb/Sb multilayer phase-change thin films, this paper systematically studies the variations in phase-change characteristics, microstructure, and device electrical performance induced by UV light exposure. The experimental results reveal that MgSb1/Sb9 thin films transform from an amorphous to a crystalline state after 30 min of UVA irradiation at a power density of 450 mW/cm2, accompanied by a narrowed band gap and an increased resistance drift coefficient. X-ray diffraction and Raman spectroscopy analyses demonstrate that the irradiated films remain predominantly amorphous without long-range ordered structural transformation. UV irradiation leads to a slight increase in the surface roughness of the thin films. Phase-change memory devices using MgSb/Sb multilayer films as the storage media can still achieve reversible SET-RESET switching after UV treatment, whereas their operating power consumption increases. This work verifies that MgSb/Sb multilayer phase-change thin films are highly sensitive to UV irradiation, which imposes obvious impacts on their microstructure and functional properties. The findings offer valuable references for the design of radiation-resistant phase-change memory devices.
HfS2 is a layered semiconductor for electronic and optoelectronic applications, but humidity-assisted native oxidation limits its ambient stability. Raman spectroscopy probes HfS2 degradation but is time-consuming and condition-sensitive. Here, we revisit a previously reported HfS2 aging dataset to develop a Raman-calibrated image-based framework for rapid, non-destructive screening of CVD-grown HfS2 films on c-plane sapphire. Photographs collected under a documented configuration yielded predefined color, histogram, texture, and spatial descriptors. A simple, interpretable regression using only CIE Lab b* with physical-range clipping achieved a within-library, query-excluded leave-one-day-out RMSE of 6.78 days for 21 queries from three optically evolving conditions: native HfS2 at 35% and 70% RH and PMMA-capped HfS2 at 70% RH. The b*-based model performed comparably to kNN (7.70 days) and significantly better than a no-information pool-mean baseline (9.84 days, p = 0.0030), indicating that more complex estimators provided no clear benefit in the present dataset. Under leave-one-pair-out evaluation of 20 image-Raman pairs, the combined image-derived estimate showed a trend-level relationship with measured normalized A1g intensity (R2 = 0.600), while ΔE gave the best individual result (R2 = 0.701). The framework identified its limits: severe degradation of native HfS2 at 70% RH was underestimated, whereas Al2O3-encapsulated HfS2 showed insufficient optical evolution for reliable chronological estimation. Accordingly, this material- and configuration-specific method is a proof-of-concept screening framework, not a universal dating model or a substitute for Raman spectroscopy. Within this scope, controlled photography provides interpretable pre-screening of broad aging states and prioritizes samples for Raman or chemical analysis.
