Research on the Reliability of Advanced Packaging under Multi-Field Coupling: A Review.

With the advancement of Moore's Law reaching its limits, advanced packaging technologies represented by Flip Chip (FC), Wafer-Level Packaging (WLP), System in Package (SiP), and 3D packaging have received significant attention. While advanced packaging has made breakthroughs in achieving high performance, miniaturization, and low cost, the smaller thermal space and higher power density have created complex physical fields such as electricity, heat, and stress. The packaging interconnects responsible for electrical transmission are prone to serious reliability issues, leading to the device's failure. Therefore, conducting multi-field coupling research on the reliability of advanced packaging interconnects is necessary. The development of packaging and the characteristics of advanced packaging are reviewed. The reliability issues of advanced packaging under thermal, electrical, and electromagnetic fields are discussed, as well as the methods and current research of multi-field coupling in advanced packaging. Finally, the prospect of the multi-field coupling reliability of advanced packaging is summarized to provide references for the reliability research of advanced packaging.

Research on Surface Morphology of Gold Micro Bumps Based on Monte Carlo Method.

In advanced packaging technology, the micro bump has become an important means of chip stacking and wafer interconnection. The reliability of micro bumps, which plays an important role in mechanical support, electrical connection, signal transmission and heat dissipation, determines the quality of chip packaging. Surface morphological defects are one of the main factors affecting the reliability of micro bumps, which are closely related to materials and bonding process parameters. In this paper, the electrodeposition process of preparing gold bumps is simulated at the atomic scale using the Kinetic Monte Carlo method. The differences in surface morphology and roughness of the plated layer are studied from a microscopic perspective under different deposition parameters. The results show that the gold micro bumps prepared by electrodeposition have better surface quality under conditions of lower deposition voltage, lower ion concentration and higher plating temperature, which can provide significant guidance for engineering applications.

Three-Dimensional Integrated Fan-Out Wafer-Level Package Micro-Bump Electromigration Study.

To meet the demands for miniaturization and multi-functional and high-performance electronics applications, the semiconductor industry has shifted its packaging approach to multi-chip vertical stacking. Among the advanced packaging technologies for high-density interconnects, the most persistent factor affecting their reliability is the electromigration (EM) problem on the micro-bump. The operating temperature and the operating current density are the main factors affecting the EM phenomenon. Therefore, when a micro-bump structure is in the electrothermal environment, the EM failure mechanism of the high-density integrated packaging structure must be studied. To investigate the relationship between loading conditions and EM failure time in micro-bump structures, this study established an equivalent model of the vertical stacking structure of fan-out wafer-level packages. Then, the electrothermal interaction theory was used to carry out numerical simulations in an electrothermal environment. Finally, the MTTF equation was invoked, with Sn63Pb37 as the bump material, and the relationship between the operating environment and EM lifetime was investigated. The results showed that the current aggregation was the location where the bump structure was most susceptible to EM failure. The accelerating effect of the temperature on the EM failure time was more obvious at a current density of 3.5 A/cm2, which was 27.51% shorter than 4.5 A/cm2 at the same temperature difference. When the current density exceeded 4.5 A/cm2, the change in the failure time was not obvious, and the maximum critical value of the micro-bump failure was 4 A/cm2~4.5 A/cm2.

Happy is stronger than sad: Emotional information modulates social attention.

Social directional cues (e.g., gaze direction; walking direction) can trigger reflexive attentional orienting, a phenomenon known as social attention. Here, we examined whether this reflexive social attention could be modulated by the emotional content embedded in social cues. By introducing emotional (happy and sad) biological motion (BM) stimuli to the modified central cuing paradigm, we found that the happy but not the sad emotional gait could significantly boost attentional orienting effect relative to the neutral gait. Critically, this "happiness advantage" effect could be extended to social attention induced by gaze. Furthermore, the observed differential emotional modulations could not be simply explained by low-level physical differences between the emotional stimuli, as inverted social cues (i.e., BM and face) failed to produce such modulation effects. Overall, these findings highlight the role of emotional information in modulating the processing of social signals, and further suggest the existence of a general emotional modulation on social attention triggered by different types of social signals. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Internal Social Attention: Gaze Cues Stored in Working Memory Trigger Involuntary Attentional Orienting.

Previous research has shown that social cues, including eye gaze, can readily guide our focus of attention-a phenomenon referred to as social attention. Here, we demonstrated that internally maintained social cues in working memory (WM) can produce an analogous attentional effect (N = 57). Using the delayed-match-to-sample paradigm combined with the dot-probe task, we found that holding irrelevant gaze cues in WM can induce attentional orienting in college-age adults. Importantly, this WM-induced attention effect could not be explained simply by the perceptual-attentional process, because the identical gaze cues that were only passively viewed and not memorized in WM could not trigger attentional orienting beyond the typical time window of social attention. Furthermore, nonsocial cues (i.e., arrows) held in WM failed to elicit the attentional-orienting effect. These findings provide new evidence for the conceptualization of WM as internally directed attention and highlight the uniqueness of social attention compared with nonsocial attention.

Cross-modal social attention triggered by biological motion cues.

Previous research has demonstrated that biological motion (BM) cues can induce reflexive attentional orienting. This BM-triggered social attention has hitherto only been investigated within visual modality. It remains unknown whether and to what extent social attention induced by BM cues can occur across different sensory modalities. By introducing auditory stimuli to a modified central cueing paradigm, we showed that observers responded significantly faster to auditory targets presented in the walking direction of BM than in the opposite direction, reflecting the notion that BM cues can trigger cross-modal social attention. This effect was not due to the viewpoint effect of the global configuration and could be extended to local BM cues without any global configuration. Critically, such cross-modal social attention was sensitive to the orientation of BM cues and completely disappeared when critical biological characteristics were removed. Our findings, taken together, support the existence of a special multimodal attention mechanism tuned to life motion signals and shed new light on the unique and cross-modal nature of social attention.

Cross-category adaptation of reflexive social attention.

Social attention is crucial for efficient social interactions and adaptive functioning in humans. However, whether this indispensable ability is unique and qualitatively distinct from nonsocial attention remains equivocal. Using the visual adaptation technique in conjunction with a modified central cueing paradigm, the current study investigated the specificity of social attention. Results revealed that adaptation to the walking direction of biological motion (BM) affected the reflexive attentional effect triggered by subsequent BM cues. Critically, preexposure to another type of social cues (i.e., eye gaze) could produce a similar aftereffect on attentional orienting elicited by BM, reflecting that social attention induced by different types of cues might share common neural substrates. By contrast, such cross-category adaptation aftereffect disappeared when adaptors changed to nonsocial cues (i.e., arrows). In the same vein, adaptation to BM cues could also exert an aftereffect on gaze cueing but not arrow cueing effect. Taken together, these findings provide evidence for the view that "social attention is special" and support the existence of "social attention detector" in the human brain. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Heritability of reflexive social attention triggered by eye gaze and walking direction: common and unique genetic underpinnings.

BACKGROUND: Social attention ability is crucial for human adaptive social behaviors and interpersonal communications, and the malfunction of which has been implicated in autism spectrum disorder (ASD), a highly genetic neurodevelopmental disorder marked by striking social deficits. METHODS: Using a classical twin design, the current study investigated the genetic contribution to individual variation in social and non-social attention abilities, and further probed their potential genetic linkage. Moreover, individual autistic traits were further measured in an independent group of non-twin participants to examine the hypothetical link between the core social attention ability and ASD. RESULTS: We found reliable genetic influences on the social attentional effects induced by two distinct cues (eye gaze and walking direction), with 91% of their covariance accounted for by common genetic effects. However, no evidence of heritability or shared genetic effects was observed for the attentional effect directed by a non-social cue (i.e. arrow direction) and its correlation with the social attention ability. Remarkably, one's autistic traits could well predict his/her heritable core social attention ability extracted from the conventional social attentional effect. CONCLUSIONS: These findings together suggest that human social attention ability is supported by unique genetic mechanisms that can be shared across different social, but not non-social, processing. Moreover, they also encourage the identification of 'social attention genes' and highlight the critical role of the core human social attention ability in seeking the endophenotypes of social cognitive disorders including ASD.

A Review of Graphene on NEMS.

BACKGROUND: Graphene is a new type of two-dimensional crystal material, and its single atomic layer structure shows many excellent physical and chemical properties such as large specific surface area, good electrical conductivity and high Young's modulus. However, few relevant patents to the topic have been reviewed and cited. This paper mainly deals with the methods of the preparations of graphene and graphene applications in NEMS sensors, NEMS devices, optics, energy storage, and biomedical fields. METHODS: At present, compared with the less effective experimental research method, the numerical simulation method has become an effective research approach. Molecular dynamics is widely used in the numerical simulation calculation. Molecular dynamics can simulate the change process of graphene in real environments. Molecular dynamics reveals the microscopic deformation under the action of external load. RESULTS: The analysis process of two structures is mainly through the external stretched or compressed force exerted on the graphene. The Young's modulus of the simulated graphene is about 0.86TPa. The simulated tensile strength is about 121GPa.The resonance frequency of graphene resonators can be changed by the tension of both ends of the beam. As the initial strain increases, the resonance frequencies also increase. For very small initial axial -strain, the tunable range reached above several hundred gigahertz. As the initial axial -strain of graphene increased, the tunable range decreased. CONCLUSION: Due to the unique properties and potential applications of graphene, it has aroused an extensive research boom in nano science world. Graphene is considered as one of the most promising materials of next generation electronic devices.