Search Results (221)

As a mountain–water city in the upper Yangtze River region, Chongqing is characterized by complex river-valley terrain, dense riverside development, extreme summer heat, high humidity, and frequent calm-wind conditions. Existing studies on waterfront thermal comfort mainly focus on plain cities, whereas mountainous riverside parks remain insufficiently understood. This study investigated summer thermal comfort in three riverside parks in Chongqing—Jiulongtan Park, Coral Park, and Jiangtan Park—through field measurements of air temperature, black globe temperature, wind speed, relative humidity, and Thermal Radiation, combined with thermal sensation vote (TSV) and thermal comfort vote (TCV) surveys. Results showed that the maximum air temperature reached 43.7 °C and the maximum black globe temperature reached 61.6 °C. The hydrophilic layer recorded the highest wind speed (1.64 ± 0.39 m/s), while the elastic layer showed high PET values (36.00–46.10 °C). Regression analysis indicated neutral PET values of 32.49–35.74 °C. Correlation analysis showed that PET, mean thermal sensation vote (MTSV), and mean thermal comfort vote (MTCV) were positively correlated with air temperature, black globe temperature, mean radiant temperature (T_mrt), and relative humidity. In contrast, PET was negatively correlated with wind speed. This study reveals the coupled effects of river-valley terrain, elevation stratification, waterfront microclimate, and landscape elements on outdoor thermal comfort, providing a scientific basis for optimizing shading, ventilation, and hydrophilic spaces in hot-humid mountain–water cities. Full article

The rapid advancement of high-performance computing has spurred growing demand for miniaturized, high-density, high-power, and highly reliable electronic packaging. Through-silicon via (TSV), as a pivotal technology enabling high-density integrated packaging, achieves vertical interconnection that reduces signal latency and power consumption while substantially improving system integration. However, inherent challenges persist due to coefficient of thermal expansion mismatches among heterogeneous materials in TSV and parasitic effects introduced by high-density TSV arrays, leading to critical concerns regarding thermomechanical reliability and signal integrity. This study focuses on TSV structures, investigating their thermomechanical reliability and electrical performance. First, the macro–micro model of 2.5D package structure was established to address cross-scale challenges based on Representative Volume Element (RVE) homogenization and sub-model technique. Then, an equivalent circuit model integrating transmission line network theory was developed and validated through full-wave electromagnetic simulations using S-parameter analysis to analyze signal transmission characteristics. Finally, by introducing an improved multi-objective grasshopper algorithm, the structural parameters of TSV are co-optimized using a genetic algorithm back propagation network (GA-BP) and an improved multi-objective grasshopper algorithm (IMOGOA) to enhance both thermomechanical reliability and electrical characteristics simultaneously. The proposed approach offers a practical and effective solution for improving the reliability and performance of high-density integrated packaging, providing valuable insights for future packaging design and optimization. Full article

Fueled by the push for “More than Moore”, three-dimensional integrated circuits (3D ICs) have become a backbone of next-generation electronics. Their complex architectures place unprecedented demands on etching technologies, which must now deliver atomic precision, stringent high-aspect-ratio (HAR) control, and virtually damage-free profiles. Meeting these challenges requires metrology capable of true 3D, quantitative analysis at the nanoscale. Atomic force microscopy (AFM) has proven essential in this regard, offering non-destructive, sub-nanometer characterization that other techniques cannot provide. This review systematically examines AFM’s pivotal role in advancing key etching processes for 3D ICs, including deep reactive ion etching of through-silicon vias (TSVs), atomic layer etching (ALE), and cryogenic plasma etching. We detail AFM’s unique contributions to quantifying sidewall roughness, verifying etch-per-cycle rates, and assessing surface damage. We also discuss how recent innovations, such as tilting-AFM, HAR probes, and automated inline systems, are overcoming traditional barriers in throughput and access to sidewalls and deep trenches. Looking forward, the integration of AFM with optical metrology, machine learning, and multi-scale modeling opens a path toward truly autonomous process control and optimization. As such, AFM stands as an indispensable tool for developing and refining the etching processes that underpin next-generation 3D semiconductor manufacturing. Full article

Three-dimensional integrated circuits (3D ICs) have emerged as a key technology to sustain scaling trends in the microelectronics industry. This advancement calls for a fundamental shift in how electrical interconnects are implemented, with through-silicon vias (TSVs) playing a pivotal role in enabling vertical connectivity between stacked chips. However, the metallization of TSVs traditionally involves elaborate and demanding processes, which can limit the speed and flexibility of prototyping and design modifications. In this paper, we investigate the use of Ultra-Precise Dispensing (UPD) technology of novel silver nanoparticle-based pastes as a simple and adaptable alternative to the metallization of TSVs process. The TSV filling process is outlined, followed by a detailed analysis of their morphology, filling quality, and electrical performance. We successfully achieve filled vias through a 280 μm thick silicon substrate with diameters down to 20 μm, resulting in an aspect ratio of up to 14:1, exhibiting favorable electrical properties. This work contributes to the achievement of dense, high-aspect ratio TSV fabrication using additive manufacturing, demonstrating a path towards reduced complexity of standard technology processes cycle, lower cost potential, and increased design flexibility. Full article

Finite element modeling (FEM) of hybrid bonding stacks for high-density 3D integration suffers from excessive computational load and prohibitive simulation time. To address this critical technical bottleneck, this paper proposes an analytical lumped-distributed equivalent circuit model based on multi-layer structures. The model incorporates both redistribution layer (RDL) parasitics and metal–insulator–semiconductor (MIS) depletion effects for comprehensive signal integrity analysis. Frequency-dependent RLGC electromagnetic parameters were extracted from through-silicon via (TSV) and RDL interconnects. These parameters were numerically calculated using MATLAB R2020a to construct the equivalent circuit model in ADS. The model was subsequently validated against COMSOL finite element simulations. The results demonstrated that the proposed methodology achieved maximum deviations below 5% for all S-parameters in double-layer structures. For 5-layer stacks, errors were controlled within 10% across the 0–40 GHz frequency range. Computation time was reduced from several minutes to seconds. The proposed equivalent circuit method significantly reduces computational time while maintaining accuracy, providing an efficient simulation methodology for signal integrity analysis and verification of hybrid bonding stack structures. Compared to existing single-layer models, this work extends the modeling approach to multi-layer hybrid bonding stacks while comprehensively accounting for both RDL parasitics and MIS depletion effects, addressing a critical gap in the current state of the art. Full article

To meet the demands for miniaturization, lightweight design, and high performance in modern electronic systems, advanced 3D TSV technology enables a substantial increase in storage capacity even within physically constrained form factors. This paper proposes a schematic design methodology and system-level integrated modeling approach for a four-layer stacked micro-module based on wafer-level packaging. By leveraging heterogeneous chip fan-out technology and TSV-based vertical stacking, the fabricated DDR3 micro-module achieves a compact footprint of 14 × 9 × 3.5 mm, a storage capacity of 4 GB, and a 64-bit bus width. Compared to conventional board-level mounting, the module reduces the footprint area by 95%. Following comprehensive multi-level testing, the micro-module fully complies with standard protocol requirements, enabling a paradigm shift in form factors for mobile computing devices while enhancing computational density and energy efficiency in data center server applications. Full article

Although many studies have demonstrated the positive effects of natural visual and auditory stimuli on human physiological and psychological states, there is limited empirical evidence on the effects on subjective comfort under different thermal environments. This study used a climatic chamber experiment to evaluate the impact of three types of natural stimuli (visual, auditory, and combined audio-visual) on physiological and psychological responses under three operative temperature conditions (26 °C, 28 °C, and 32 °C). In total, 24 participants were recruited. Physiological indicators, including heart rate variability, skin conductance level (SCL), skin temperature (ST), and blood pressure, as well as psychological indicators including thermal sensation (TSV), thermal comfort (TCV), visual comfort (VCV), and acoustic comfort (ACV), were collected. The results show that TCV was significantly and positively correlated with both VCV and ACV. The visual stimuli produced the most significant decrease in TSV and the greatest increase in TCV, while combined audio-visual stimuli had the most significant impact on physiological responses. At 26 °C, the combined audio-visual stimuli group reduced heart rate by 6.08%. However, at 32 °C, most physiological and psychological restoration indicators showed no significant changes. These findings provide theoretical references for health-oriented multisensory environmental design in urban areas. Full article

In this study, the Monte Carlo (MC) method is employed to generate the diameter and relative positional distributions of carbon nanotubes (CNTs). Based on this, we develop a three-layer thermal model for a copper-carbon nanotube (Cu-CNT) through-silicon via (TSV). By integrating Gauss–Hermite quadrature with the Law of Large Numbers (LLN), an analytical expression for thermal conductivity is derived, enabling efficient and accurate estimation of the thermal conductivity of Cu-CNT-filled TSV. Contrary to expectations, the thermal conductivity of TSV does not increase significantly with CNT volume fraction, primarily due to the interfacial thermal resistance at Cu-CNT and CNT-CNT junctions. Through calibration against previously reported experimental data, the effective Cu-CNT interfacial thermal resistance is estimated to be on the order of 10⁻⁷ m²K/W. Comparison with previously reported effective thermal conductivity data of Cu-CNT composites shows that the model maintains an error below 2% when the CNT volume fraction is below 10%. The model is therefore most suitable for low CNT volume fractions, where the assumed spatial distribution and structural simplifications remain physically valid. Furthermore, this study investigates the influence of TSV length on thermal performance, predicts the variation in thermal conductivity of Cu-CNT composites under different volume fractions, and the extracted thermal conductivity values are further used as material inputs for device-level electro-thermal COMSOL 6.1 simulations. Full article

High-frequency transmission loss in Redistribution Layer-Through Silicon Via (RDL-TSV) interconnect structures is a critical factor influencing the performance of three-dimensional integrated circuits. This study aims to enhance the prediction accuracy of high-frequency losses by balancing the training accuracy and computational efficiency of traditional full-wave simulation and equivalent circuit models. A Physical Information Convolutional Neural Network (PI-CNN) prediction model was developed based on convolutional neural networks, incorporating the skin effect as physical guidance. A multi-criteria decision-making framework was then proposed by integrating the PI-CNN model with a genetic algorithm. Results show that the PI-CNN model achieves stable single-prediction times under 3 s, with prediction loss errors below 0.1 dB and an R² value of 0.987, significantly improving the accuracy of high-frequency loss prediction. Through multi-criteria decision optimization, the randomness inherent in genetic algorithms enables systematic exploration of favorable design options within the design space. This approach ensures that the final design maintains consistent performance and robustness under anticipated manufacturing variations. The study provides a data-driven, physics-guided approach for evaluating and optimizing high-frequency performance in advanced packaging. Full article

Objective: White matter hyperintensity (WMH) is one of the most common and prominent changes seen in elderly individuals, especially on MRI. WMH is associated with serious conditions such as hemorrhagic and ischemic stroke, depression and dementia. Recently, the relationship between cerebral venous diameter and WMH was described. This study aimed to investigate the relationship between the Fazekas scale, which evaluates the severity of WMH, and cerebral vein diameters, age and clinical outcomes analysis. Materials and Methods: MRI images of 660 patients were examined retrospectively. FLAIR and SWI (MiniP) images were used to evaluate WMH and cerebral vein diameters. Internal cerebral veins (ICV), thalamostriate veins (TSV), anterior septal veins (ASV) and superior sagittal sinus (SSS) diameters were measured. Cerebral vein diameters were compared with age, WMH, hypertension, hyperlipidemia, diabetes mellitus, lacunar infarct and microhemorrhage presence. Results: In the presence of hypertension, hyperlipidemia, diabetes, lacunar infarction and microhemorrhage, Fazekas score, mean ICV-right, ICV-left, ASV-right, ASV-left, TSV-right and TSV-left values were significantly higher. The mean ICV-right, ICV-left, ASV-right, ASV-left, TSV-right and TSV-left values of the middle-aged and elderly groups were significantly higher than the young group. A strong positive correlation was observed between age and mean ICV-right, ICV-left, ASV-right and ASV-left values, while a moderate positive correlation was shown with TSV-right and TSV-left values. A weak negative correlation was determined with SSS values. Conclusions: Cerebral vein diameter increases with age and is associated with the severity of WMH. Clinicians can monitor cerebral vein diameter to predict the severity of WMH. Full article

Electromagnetic compatibility (EMC) diagnostics for high-density through-silicon via (TSV)-based chips face significant challenges due to complex three-dimensional electromagnetic coupling and inefficient source reconstruction workflows. This paper proposes a universal contribution-driven dipole preprocessing technique tailored for dipole array-based source reconstruction methods, addressing the critical efficiency-accuracy trade-off inherent in traditional approaches. The core innovation is an influence factor-based evaluation-elimination mechanism that extracts effective dipole components aligned with the structural characteristics of TSV-based chips and multilayer printed circuit boards, while eliminating redundant dipoles independently of the downstream source reconstruction algorithm. Validation on a multilayer PCB (1 GHz) and a TSV-based chip (4 GHz) demonstrates that the technique maintains high reconstruction accuracy, with error increase limited to ≤0.2% for the simulated PCB and ≤0.05% for the physically measured TSV-based chip. Computational time is reduced by 28–61% for the PCB and 20–28% for the TSV chip compared to traditional source reconstruction without preprocessing. For TSV-based chips exhibiting complex electromagnetic behavior, the technique delivers consistent performance across different dipole configurations, providing a fast, robust, and universal EMC diagnostic tool for high-density electronic devices. Full article

In industrial and logistics settings, the use of soft and rigid spinal exoskeletons has been increasing. However, under a unified assistance level and comparable work scenarios, systematic comparisons of their effects on users’ thermophysiological responses and subjective thermal perceptions remain limited. Twenty male participants performed manual handling tasks under three load conditions (5, 10, and 15 kg) in three experimental conditions: without the exoskeleton (WEXO), a rigid exoskeleton (REXO), and a soft exoskeleton (SEXO). Metabolic rate, mean skin temperature (MST), thermal comfort vote (TCV), and thermal sensation vote (TSV) were measured. The key findings are as follows: Compared with WEXO, both exoskeletons significantly reduced metabolic rate. Across all loads, SEXO yielded a lower metabolic rate than REXO and showed a more gradual linear increase as the load increased, whereas REXO exhibited a larger rise at 15 kg. Overall, MST was higher in REXO than in SEXO. Wearing an exoskeleton was often associated with increased skin temperature at 5–10 kg, yet MST decreased for both exoskeletons at 15 kg. Subjective ratings further indicated better TCV and TSV with SEXO than with REXO, with the difference more pronounced under higher loads. Taken together, under the conditions of this study, the soft exoskeleton appears to better balance assistive benefits and thermal comfort. Nevertheless, its heat transfer and heat dissipation performance should be further optimized in future designs. Full article

This paper is dedicated to investigating how short-term indoor temperature drift influences occupants’ thermal sensation in residential nZEB buildings and how this affects the applicability of steady-state comfort prediction. Residential buildings frequently operate under transient conditions, where the classical PMV approach may deviate from reported sensation. The objective of this paper is to evaluate the agreement between steady-state PMV and occupants’ thermal sensation votes under winter conditions to test a regression-based correction index A_eff and an adjusted indicator PMV_adj while preserving the PMV concept. The study uses high-resolution measurements of indoor air temperature and mean radiant temperature synchronised with TSV responses, followed by statistical evaluation using error metrics and correlation analysis. The results show that baseline PMV correlates well with TSV but exhibits a consistent magnitude mismatch under transient conditions. The proposed PMV_adj reduces this mismatch, decreasing NRMSE from 17.61% to 14.00% and slightly improving agreement with Pearson r = 82.18%, R² = 67.54%. Regression analysis shows that A_eff is strongly associated with the indoor air temperature drift rate ΔT_in/Δt with R² = 0.6805, but has a weaker relationship with ΔT_MRT/Δt, R² = 0.1851. The research provides a practical basis for improving PMV-based comfort assessment during winter operation in residential nZEB. Full article

Pocket parks serve as vital everyday green spaces in high-density cities, yet many remain underused, especially in hot–humid regions where thermal discomfort restricts outdoor activities. Traditional pocket-park classification approaches overlook actual usage patterns of pocket parks, and existing studies have not examined whether thermal environments influence pocket park use, nor have they adequately addressed thermal comfort from the perspective of user needs. To address these gaps, this study investigates usage behavior, thermal environments, and thermal comfort demands in pocket parks in Guangzhou, a representative hot–humid city in southern China. Through a preliminary reconnaissance survey, this study selected three typical pocket parks for detailed case-study investigation, and the corresponding usage characteristics were systematically identified. Thermal environments and thermal comfort demands were collected separately through on-site thermal measurements and questionnaire surveys. Correlation and comparative analyses were then conducted to examine the relationships among usage characteristics, thermal environmental conditions, and thermal comfort. The findings reveal that (1) the usage rate of residential pocket parks showed the most sensitivity to WBGT, followed by business pocket parks, while the usage rate of traffic pocket parks showed no significant correlation with WBGT; and (2) business parks had the highest thermal sensitivity with PET, followed by residential and traffic types. A one-unit decrease in TSV corresponds to PET reductions of 11.1 °C, 12.5 °C, and 16.6 °C for business, residential, and traffic parks, respectively; (3) among thermal environmental parameters, wind speed exerted the greatest influence on the subjective thermal responses of users in both residential and business pocket parks. As for usage characteristics, activity type was the most significant factor affecting the thermal sensation of users in the traffic pocket park, while short-term thermal experience played the dominant role for users in the business pocket park. The results of this study offer a scientific basis for user-centered, climate-responsive design strategies for pocket parks in hot–humid regions. Full article

Microelectronic packaging is crucial for protecting, powering, and interconnecting semiconductor chips, playing a critical role in the functionality and reliability of electronic devices. With the growth in complexity and miniaturization of these products, the implementation of efficient inspection techniques becomes crucial in preventing failures that may result in device malfunctions. This review paper examines the progress made in utilizing Scanning Acoustic Microscopy (SAM) to assess the structural integrity of microelectronic systems within the broader field of Nondestructive Evaluation/Testing (NDE/T) methods. With an exclusive emphasis on SAM, we point out SAM technological advancements in multi-die stacking, Through Silicon Vias (TSV), and hybrid bonding inspection that improve inspection sensitivity and resolution required to be prepared for upcoming challenges accompanying 3D- and heterogeneous integration architectures. Some of these approaches compromise the depth of inspection for the benefit of lateral resolution, while others do not sacrifice the in-depth range of evaluation. These developments are of the utmost importance in addressing the substantial obstacles associated with examining microelectronic packages, facilitating the early detection of potential failures, and enhancing the reliability and robustness of semiconductor devices. Furthermore, our discussion consists of the fundamental principles and practical approaches of SAM. It also examines recent investigations that integrate SAM with machine learning concepts and the application of deep learning models in order to automate defect detection and characterization, thus substantially augmenting the efficiency of microelectronic package assessments. Full article