Search Results (146)

Marine biofouling significantly impacts the performance and longevity of polymer-based marine structures, particularly those designed for hydrodynamic applications such as Vortex-Induced Vibration suppression systems. Traditional antifouling solutions rely on copper-based multilayer coatings, which present challenges including mechanical vulnerability (e.g., chipping and scratching), high material and labor demands, and environmental concerns such as volatile organic compound emissions and copper leaching. Recent developments in material science have introduced an alternative system involving the direct incorporation of copper oxide (Cu₂O) into high-density polyethylene (HDPE) during the molding process. This study conducts a comparative life cycle assessment (LCA) of two antifouling integration methods—System 1 (traditional coating-based) and System 2 (Cu₂O-impregnated HDPE)—evaluating their environmental impact across production, application, use, and end-of-life stages. The functional unit used for this study was 1 square meter for a time period of five years. Using ISO 14040-compliant methodology and data from Ecoinvent and OpenLCA, three impact categories were assessed: global warming potential (GWP), cumulative energy demand (CED), and marine aquatic ecotoxicity Potential (MAETP). The results indicate that System 2 outperforms System 1 in GWP (4.42 vs. 5.65 kg CO₂-eq), CED (75.3 vs. 91.0 MJ-eq), and MAETP (327,002 vs. 469,929 kg 1,4-DCB-eq) per functional unit over a five-year lifespan, indicating a 21.8%, 17.3%, and 30.4% reduction in the key impact factors, respectively. These results suggest that direct Cu₂O incorporation offers a more environmentally sustainable and mechanically resilient antifouling strategy, supporting the potential of embedded antifouling systems to shift industry practices toward more sustainable marine infrastructure. Full article

Hydroxychloroquine (HCQ), a cornerstone therapeutic agent for autoimmune diseases, requires precise serum concentration monitoring due to its narrow therapeutic window. Current HCQ monitoring methods such as HPLC and LC-MS/MS are sensitive but costly and complex. While electrochemical sensors offer rapid, cost-effective detection, their large chambers and high sample consumption hinder point-of-care use. To address these challenges, we developed a microfluidic electrochemical sensing platform based on a screen-printed carbon electrode (SPCE) modified with a hierarchical nanocomposite of gold nanoparticles (AuNPs), copper-based metal–organic frameworks (Cu-MOFs), and multi-walled carbon nanotubes (MWCNTs). The Cu-MOF provided high porosity and analyte enrichment, MWCNTs established a 3D conductive network to enhance electron transfer, and AuNPs further optimized catalytic activity through localized plasmonic effects. Structural characterization (SEM, XRD, FT-IR) confirmed the successful integration of these components via π-π stacking and metal–carboxylate coordination. Electrochemical analyses (CV, EIS, DPV) revealed exceptional performance, with a wide linear range (0.05–50 μM), a low detection limit (19 nM, S/N = 3), and a rapid response time (<5 min). The sensor exhibited outstanding selectivity against common interferents, high reproducibility (RSD = 3.15%), and long-term stability (98% signal retention after 15 days). By integrating the nanocomposite-modified SPCE into a microfluidic chip, we achieved accurate HCQ detection in 50 μL of serum, with recovery rates of 95.0–103.0%, meeting FDA validation criteria. This portable platform combines the synergistic advantages of nanomaterials with microfluidic miniaturization, offering a robust and practical tool for real-time therapeutic drug monitoring in clinical settings. Full article

The traditional aging of cachaça has been performed with different types of wood barrels. Although it is efficient for incorporating phenolics, volatiles, and color into the drink, it is time-consuming for the industry. Alternative aging processes, such as the use of wood chips, have been proposed, and they have the advantage of achieving aging in a shorter time and producing a quality and innovative drink. Therefore, the influence of jackfruit wood barrel and chips and micro-aeration was investigated during cachaça aging. For that, five treatments were used—stainless steel tank (control); stainless steel tank and micro-aeration (control); jackfruit wood barrel; stainless steel tank with jackfruit chips; and stainless steel tank with jackfruit chips and micro-aeration—during two aging times (40 and 79 days). Aging cachaça with jackfruit wood led to increased physicochemical, color, and total phenolic contents, whereas alcoholic degree, lightness, and copper contents decreased. No influence was observed on higher alcohols. Nineteen phenolic compounds were identified in the jackfruit wood aged cachaça by HPLC-DAD-FLD. Myricetin was predominant, a potential marker for jackfruit wood. Longer aging time decreased the alcoholic degree and total ester, but it increased dry extract, density, total and volatile acidity, and it improved the quality of cachaça. The use of chips accelerated aging, whereas micro-aeration led to decreased myricetin. PCA and HCA clustered the samples into three groups: the first was correlated with several flavonoids and coumarins; the second with myricetin, piceatannol, and trans-ferulic acid; and the last with ellagic acid. The use of jackfruit chips in the aging of cachaça has been shown to be a promising innovation. Full article

We present a compact and cost-effective real-time PCR system designed for point-of-care testing (POCT), utilizing a PCB-based disposable chip and an open-platform CMOS camera. The system integrates precise thermal cycling with software-synchronized fluorescence detection and provides real-time analysis through a dedicated user interface. To minimize cost and complexity, a polycarbonate reaction chamber was integrated with a PCB-based heater and thermistor. A slanted LED illumination setup and an open-platform USB camera were employed for fluorescence imaging. Signal alignment was enhanced using device-specific region-of-interest (ROI) tracking based on copper pad corner detection. Thermal cycling performance achieved a heating rate of 8.0 °C/s and a cooling rate of −9.3 °C/s, with steady-state accuracy within ±0.1 °C. Fluorescence images exhibited high dynamic range without saturation, and the 3σ-based ROI correction method improved signal reliability. System performance was validated using Chlamydia trachomatis DNA standard (10³ copies), yielding consistent amplification curves with a Ct standard deviation below 0.3 cycles. These results demonstrate that the proposed system enables rapid, accurate, and reproducible nucleic acid detection, making it a strong candidate for field-deployable molecular diagnostics. Full article

The development of chip manufacturing and advanced packaging technologies has significantly changed redistribution layers (RDLs), leading to shrinking line width/spacing, increasing the number of build-up layers and package size, and introducing organic materials such as polyimide (PI) for dielectrics. The fineness and complexity of structures, combined with the temperature-dependent and viscoelastic properties of organic materials, make it increasingly difficult to predict the thermo-mechanical behavior of wafer-level Cu-PI RDL structures, posing a severe challenge in warpage prediction. This study models and simulates the thermo-mechanical response during the manufacturing process of Cu-PI RDL at the wafer level. A cross-scale wafer-level equivalent model was constructed using a two-level partitioning method, while the PI material properties were extracted via inverse fitting based on thermal warpage measurements. The warpage prediction results were compared against experimental data using the maximum warpage as the indicator to validate the extracted PI properties, yielding errors under less than 10% at typical process temperatures. The contribution of RDL build-up, wafer backgrinding, chemical mechanical polishing (CMP), and through-silicon via (TSV)/through-glass via (TGV) interposers to the warpage was also analyzed through simulation, providing insight for process risk evaluation. Finally, an artificial neural network was developed to correlate the copper ratios of four RDLs with the wafer warpages for a specific process scenario, demonstrating the potential for wafer-level warpage control through copper ratio regulation in RDLs. Full article

As CMOS technology continues to downsize to the nanometer range, the exponential growth predicted by Moore’s Law has been significantly decelerated. Doubling chip density in the two-dimensional domain will no longer be feasible without further device downsizing. Meanwhile, emerging new device technologies, which may be incompatible with the mainstream CMOS technology, offer potential performance enhancements for system integration and could be options for a More-than-Moore system. Additionally, the explosive growth of artificial intelligence (AI) demands ever-high computing power and energy-efficient computing platforms. Heterogeneous multi-chip integration, which combines diverse components or a larger number of functional blocks with different process technologies and materials into compact 3D systems, has emerged as a critical pathway to overcome the performance limitations of monolithic integrated circuits (ICs), such as limited process/material options, low yield, and multifunctional design complexity. Furthermore, it sustains Moore’s Law progression for a further smaller footprint and higher integration density, and it has become pivotal for “More-than-Moore” strategies in the next CMOS technology revolution. This approach is also crucial for sustaining computational advancements with low-power dissipation and low-latency interconnects in the coming decades. The key techniques for heterogeneous wafer-to-wafer bonding involve both copper-to-copper (Cu-Cu) and dielectric-to-dielectric bonding. This review provides a comprehensive comparison of recent advancements in Cu-Cu bonding techniques. Major issues, such as plasma treatment to activate bonding surfaces, passivation to suppress oxidation, Cu geometry, and microstructure optimization to enhance interface diffusion and regrowth, and the use of polymers as dielectrics to mitigate contamination and wafer warpage, as well as pitch size scaling, are discussed in detail. Full article

Electronic packaging can transform the chip to a device for assembly. Soldering and bonding are important procedures in the process of electronic packaging. The continuous development of packaging architecture has driven the emergence of improved soldering and bonding processes. At the same time, conventional soldering and bonding processes are still widely used in device packaging. This paper introduces two kinds of technologies in wafer bonding, direct and indirect, expounds on five kinds of die attachment processes, and also describes the process of ball bonding and wedge bonding in wire bonding in detail. Flip chip bonding and methods for making bumps are also described in depth. Bump bonding processes are vital for 3D-SiP packages, and the bonding technology of copper bumps is a research hotspot in the field of advanced packaging. The surface mount technology and sealing technology used in some electronic devices are also briefly introduced. This paper provides insights for researchers studying soldering and bonding in contemporary electronic device packaging. Full article

This study presents the preparation of hybrid iron oxide nanocomposites through a two-step process combining microfluidic-assisted synthesis and post-synthetic surface modification. Fe₃O₄ nanoparticles were synthesized and simultaneously functionalized with salicylic acid using a three-dimensional vortex-type microfluidic chip, enabling rapid and uniform particle formation. The resulting Fe₃O₄/SA nanostructures were further modified with either silver or copper oxide to form iron oxide nanocomposites with enhanced antimicrobial functionality. These nanocomposites were subsequently integrated into silica aerogel matrices using a dip-coating approach to improve surface dispersion, structural stability, and biocompatibility. The structural and morphological properties of the samples were investigated using XRD, FT-IR, TEM with SAED analysis, and Raman microscopy. In vitro cytotoxicity and antimicrobial assays demonstrated that Fe₃O₄/SA–Ag and Fe₃O₄/SA–CuO exhibit potent antibacterial activity and cell type-dependent biocompatibility. In vivo biodistribution studies showed no accumulation in major organs and selective clearance via the spleen, validating the systemic safety of the platform. These findings highlight the potential of the synthesized nanocomposites as biocompatible, antimicrobial coatings for advanced biomedical surfaces. Full article

This paper presents the design and characterisation of a novel double-sided cooling, wire-bondless half-bridge power module incorporating silver sintering technology and silicon carbide MOSFETs. Initially, the module was meticulously designed, optimised, and simulated using Ansys (Electronics Desktop 2021 R1) Q3D and Icepak to assess its stray parameters and thermal performance, respectively. The module has a low simulated stray inductance of 4.7 nH, which would be even lower in a multi-chip version of the design. Additionally, the thermal performance of the double-sided power module is compared with the single-sided version, showing a 30 °C reduction in junction temperature. Following the design work, a double-sided cooled half-bridge module was successfully fabricated, which underwent double pulse analysis and single-phase inductive load testing. Die attachment within the module employs nanosilver paste, with the flexibility to adjust the length of the copper connector to meet diverse requirements. The design exhibits remarkable compactness, and comprehensive electrical testing affirms its suitability for practical applications. Full article

Through-Silicon-Via (TSV) technology is of crucial importance in the process of defect-free copper filling in vias. In this study, the small molecule 2-mercapto-1-methylimidazole (SN2) is proposed as a new leveler. It enables bottom-up super-filling of blind vias without the need for inhibitors. Atomic force microscopy (AFM), X-ray diffraction (XRD), and XPS were employed to characterize the surface morphology, crystal structure, and adsorption properties of copper crystals in these systems. Meanwhile, by means of electrochemical measurements, the inhibitory effect of the leveler SN2 on copper ion deposition and the synergistic effect between SN2 molecules and other additives were investigated. The LSV test indicated that additive SN2 inhibited copper electrodeposition after being added to the plating solution, and this inhibitory effect enhanced with increasing SN2 concentration. In the actual plating wafer test (1 ASD plating for 1 min, 5 ASD plating for 5 min, and 10 ASD plating for 1 h), the best plating effect was achieved at 3 ppm, which verified the conjecture of the galvanostatic measurements. Moreover, XPS and computer simulations revealed that SN2 could be adsorbed onto the copper surfaces. This work will inspire the discovery of new effective levelers in the future. Full article

Microfluidic technology is an emerging interdisciplinary field that uses micropipes to handle or manipulate tiny fluids in chemistry, fluid physics, and biomedical engineering. As one of the rapid prototyping methods, the three-dimensional (3D) printing technique, which is rapid and cost-effective and has integrated molding characteristics, has become an important manufacturing technology for microfluidic chips. Polymethyl-methacrylate (PMMA), as an exceptional thermoplastic material, has found widespread application in the field of microfluidics. This paper presents a comprehensive process study on the fabrication of fused deposition modeling (FDM) 3D-printed PMMA microfluidic chips (chips), encompassing finite element numerical analysis studies, orthogonal process parameter optimization experiments, and the application of 3D-printed integrated microfluidic reactors in the reaction between copper ions and ammonium hydroxide. In this work, a thermal stress finite element model shows that the printing platform temperature was a significant printing parameter to prevent warping and delamination in the 3D printing process. A single printing molding technique is employed to fabricate microfluidic chips with square cross-sectional dimensions reduced to 200 μm, and the microchannels exhibited no clogging or leakage. The orthogonal experimental method of 3D-printed PMMA microchannels was carried out, and the optimized printing parameter resulted in a reduction in the microchannel profile to Ra 1.077 μm. Finally, a set of chemical reaction experiments of copper ions and ammonium hydroxide are performed in a 3D-printed microreactor. Furthermore, a color data graph of copper hydroxide is obtained. This study provides a cheap and high-quality research method for future research in water quality detection and chemical engineering. Full article

This paper presents a non-enzymatic sensor for glucose detection in an environment where glucose and insulin coexist. The sensor is based on a three-electrode chip fabricated by etching the copper foil of a printed circuit board. The working electrode is coated with a graphene oxide-polyvinyl alcohol composite film, followed by the electroplating of a nickel–cobalt layer and an additional surface treatment using O₂ plasma. The experimental results indicate that within a glucose concentration of 2 mM to 10 mM and an insulin concentration of 0.1 mM to 1 mM, the measured current exhibits a linear relationship with the concentration of glucose or insulin, regardless of whether cyclic voltammetry or linear sweep voltammetry is used. However, the detection limit for insulin is 0.01 mM, ensuring that glucose detection remains unaffected by insulin interference. In this sensor, nickel–cobalt serves as a catalyst for glucose and insulin detection, while the graphene oxide-polyvinyl alcohol composite enhances sensing performance. Full article

We developed a metal-compatible RFID dipole antenna. The antenna consists of three layers, including the top metal, dielectric substrate, and bottom metal, with the top metal and bottom metal of the dipole antenna shorted at the side edges of the antenna. In order to accurately measure the gain and reflection coefficient (|S11|) of the antenna in the desired frequency band, an impedance matching circuit was created using an open stub around the feeding section of the antenna. The simulation and measurement results of the |S11| and antenna’s realized gain are presented in this paper. The measured |S11| has similar characteristics to the design results at around 915–940 MHz. The size of the proposed antenna is 70 mm × 50 mm × 1.636 mm. In addition, the antenna can be bent at 0, 3, or 5 divisions to fit curved metal objects such as lithium-ion batteries (LIBs). This antenna structure is a fundamental area of study for future application to flexible substrates. Conductive adhesive tape (copper tape) was used to connect each section. The surface of the copper tape was fixed with adhesive to prevent it from peeling off. In the simulation and measurement, it was confirmed that our proposed antenna could operate around the desired frequency band. In the future, we plan to install an IC chip in the antenna input section and work towards implementing it in society. Full article

With the development of high-density integrated chips, low-k dielectric materials are used in the back end of line (BEOL) to reduce signal delay. However, due to the application of fine-pitch packages with high-hardness copper pillars, BEOL is susceptible to chip package interaction (CPI), which leads to reliability issues such as the delamination of interlayer dielectric (ILD) layers. In order to improve package reliability, the effect of CPI at multi-scale needs to be explored in terms of package integration. In this paper, the stress of BEOL in the flip-chip chip-scale packaging (FCCSP) model during thermal cycling is investigated by using the finite-element-based sub-model approach. A three-dimensional (3D) multi-level finite element model is established based on the FCCSP. The wiring layers were treated by the equivalent homogenization method to ensure high prediction accuracy. The stress distribution of the BEOL around the critical bump was analyzed. The cracking risk of the interface layer of the BEOL was assessed by pre-cracking at a dangerous location. In addition, the effects of the epoxy molding compound (EMC) thickness, polyimide (PI) opening, and coefficient of thermal expansion (CTE) of the underfill on cracking were investigated. The simulation results show that the first principal stress of BEOL is higher at high-temperature moments than at low-temperature moments, and mainly concentrated near the PI opening. Compared with the oxide layer, the low-k layer has a higher risk of cracking. A smaller EMC thickness, lower CTE of the underfill, and larger PI opening help to reduce the risk of cracking in the BEOL. Full article

Multi-chip parallel power modules are highly favored in applications requiring high capacity and high switching frequency. However, the dynamic current imbalance between parallel chips caused by asymmetric layouts limits the available capacity. This paper presents a method to optimize dynamic current distribution by adjusting the lengths and connection points of bond wires. For the first time, a response surface model and nonlinear constraint optimization algorithm are introduced, along with parameter analysis based on finite element methods, to establish the response surface models for the parasitic inductance of bond wires and DBC (direct bonded copper). By leveraging the optimization goals for parasitic inductance and the analytical expressions of all response surfaces, the dynamic current sharing issue was transformed into a nonlinear constrained optimization problem. The solution to this optimization problem identified the optimal connection points for the bond wires, enhancing dynamic current sharing performance. Simulations and experiments were conducted, revealing that the optimized automotive-grade module exhibited a significant reduction in current differences between parallel branches, from 41.7% to 5.03% compared with the original design. This indicated that the proposed optimization scheme for adjusting bond wire connection points could significantly mitigate current disparities, thereby markedly improving current distribution uniformity. Full article