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This paper aims to study the effect of ultrasonic aluminum (Al) bonding and lamination processes on the electrical performance of copper indium gallium (di)selenide (CIGS) thin film photovoltaic (TFPV) solar panels. Ultrasonic Al bonding on the MoSe2 layer of the CIGS TFPV solar panel was performed in three configurations: eight bonds, 16 bonds, and parallel configurations. The lamination process was performed on the Al bonds with MoSe2 layers of the CIGS TFPV solar panel. Ultrasonic bonding and lamination processes significantly affect the electrical performance of CIGS TFPV solar panels. Open circuit voltage, Voc is the least affected electrical characteristic with the application of ultrasonic bonding and lamination processes as compared to short circuit current (Isc), current density (Jsc), maximum power (Pmpp), fill factor (FF), and efficiency. 8-bonds configuration has the highest efficiency, ranging from 11.45% to 13.86% throughout unique connections of I-V measurement, compared to 16-bonds ranging from 7.99% to 10.77%, and parallel configurations, ranging from 9.14% to 11.92%. The notable variations in electrical properties with the processes used to create laminated CIGS TPFV solar panels with ultrasonic Al bonding can be explained by physical examination and lock-in infrared (IR) thermography. The ultrasonic Al bond is best suited to be used as the interconnection mean in the CIGS TFPV solar panel compared to that of conductive adhesive that has been widely applied nowadays. [ABSTRACT FROM AUTHOR]

Alcubierre's warp-drive was the first to introduce superluminal travel from different approaches. Instead of creating a shortcut through spacetime via a wormhole, geometrodynamics of simultaneously contracting and expanding spacetime were conjectured. However, both methods require exotic matter that violates energy conditions. In this paper, we employ the concept of braneworld that naturally influences spacetime geometrodynamics. Starting from defining and developing the spacetime metric of the braneworld warp bubble, the expression for energy densities as a function of relevant parameters which contributes to the braneworld approach of superluminal travel by hyperspace-drive was derived. [ABSTRACT FROM AUTHOR]

The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) infections that were first detected in Wuhan, China, at the end of 2019 led to the state of the global COVID-19 pandemic declared by the World Health Organization in March 2020. Thus, the world faces a new challenge to control the spread of the virus. The pandemic highlighted the need for rapid detection of infections that would be able to accurately screen the population much more rapidly and economically than the gold standard molecular biology-based tools such as quantitative real-time reverse transcription polymerase chain reaction. Such screening measures would be able to isolate infected individuals, including those showing no symptoms, and provide early treatments before more serious complications develop, thus allowing for the spread of infections to be better controlled without the implementation of socioeconomically crippling lockdowns. In this review, we present a comprehensive overview of the major advances in the use of electrolyte-gated field effect transistor-based biosensors for the detection of viruses, including their use for SARS-CoV-2 detection. We describe the main types of bioreceptors used for the detection of viruses in general and those used for COVID-19 in detail. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to investigate the effect of physical vapor deposition (PVD)-coated stencil wall aperture on the life span of fine-pitch stencil printing. Design/methodology/approach: The fine-pitch stencil used in this work is fabricated by electroform process and subsequently nano-coated using the PVD process. Stencil printing process was then performed to print the solder paste onto the printed circuit board (PCB) pad. The solder paste release was observed by solder paste inspection (SPI) and analyzed qualitatively and quantitatively. The printing cycle of up to 80,000 cycles was used to investigate the life span of stencil printing. Findings: The finding shows that the performance of stencil printing in terms of solder printing quality is highly dependent on the surface roughness of the stencil aperture. PVD-coated stencil aperture can prolong the life span of stencil printing with an acceptable performance rate of about 60%. Originality/value: Stencil printing is one of the important processes in surface mount technology to apply solder paste on the PCB. The stencil's life span greatly depends on the type of solder paste, stencil printing cycles involved and stencil conditions such as the shape of the aperture, size and thickness of the stencil. This study will provide valuable insight into the relationship between the coated stencil wall aperture via PVD process on the life span of fine-pitch stencil printing. [ABSTRACT FROM AUTHOR]

This article reviews corrosion in electronic packaging mainly in the semiconductor industry over the world. The previous study was reviewed scientifically to highlight the significant work on corrosion in electronic packaging. A total of 467 and 762 studies were found in the IEEE Explore and Scopus databases from 2010 to 2020, respectively. After the search was limited to articles and proceedings, the databases showed only 319 from IEEE and 694 from Scopus. The keywords searching for this topic also emphasized corrosion wire bonding, corrosion leadframe, and corrosion solder. When searching for articles and proceedings were divided into three (3) categories such as academia, industry, and collaborative works, the database from collaborative works showed only 57 and 108 results in IEEE and Scopus, respectively. The studies were classified according to the process after some analysis using Microsoft Excel. Most of the previous studies were on corrosion in electronic packaging. From the study, we found that most of the journal articles were published by academia while the proceeding was published by industry. This information was extracted from IEEE Explore and Scopus databases. Since 2010, the trend of collaborative works among the industry and academia showed increased from 13 to 165 total publications in 2020. This review is significant to give an overview of the collaborative works between industry and academia on the corrosion issue in electronic packaging. [ABSTRACT FROM AUTHOR]

An accelerated reliability testing via thermal cycling test (TCT) was used to test ball grid array (BGA) components’ reliability. Five variables were observed; control sample J and samples K, L, M, and N were BGA component samples that have been exposed to TCT between 500 and 1250 cycles with the TCT profile in the range of 0 °C–100 °C. The crack orientation of the individual solder joint was analyzed along with the propagation path pattern on the solder array of the BGA component pad by analyzing the dye and pull test results that were then mapped and analyzed using the cardinal and ordinal directions approach. This is to determine the crack propagation path direction in the solder array and track the potential of warpage on the BGA package as the TCT cycles progressed. A cross section was performed on sample M with the 3-D X-ray and scanning electron microscopy (SEM) analysis to observe the solder joints’ fracture lines and surface topographies. The results showed that individual solder joint crack orientation is correlated to the crack propagation location on the BGA package. The solder joint from northwest (NW), northeast (NE), southeast (SE), and southwest (SW) of the BGA package is prone to solder crack compared to the solder joint array in the middle. A solder grain structure coarsening occurred at the crack propagation due to the high cyclic strain from the TCT. [ABSTRACT FROM AUTHOR]

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Methanesulfonic acid (MSA) has been widely used in the electroplating step at a backend semiconductor assembly process. This process comes after component encapsulation, which serves primarily to protect internal components of a device as well as to prevent ingression of chemical byproducts. The objective of this article is to study sulfur (S) ingression activities with respect to both electroplating and encapsulation processes and their effect on leadframe surface conditions. This can be achieved through observation of leadframe surface condition on samples prepared through laser ablation or mechanical decapsulation. Results from 17 engineering lots show that 25% of samples analyzed were observed with leadframe surface irregularities. The energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the trace of S element on the area with surface irregularities, which can be linked to S ingression based on the trace of its path from outside, probably due to the existence of a microgap on the package. These findings provide a clearer understanding of the ingression path of S for encapsulated copper (Cu) leadframe. Even though ingression of S does not directly cause a failure, it is thought that this could act as a precursor to further failure mechanisms such as corrosion-like phenomena. [ABSTRACT FROM AUTHOR]