Electroplated Copper Additives for Advanced Packaging: A Review.

Acid copper electroplating stands as a core technology in advanced packaging processes, facilitating the realization of metal interconnects, bumps, vias, and substrate wiring between transistors. The deposition quality of copper interconnect materials has a crucial impact on the final performance of chips, directly influencing their yield, reliability, and stability. In this intricate process, additives play a pivotal role in regulating the deposition quality and behavior of metal copper. This mini-review comprehensively summarizes the recent research progress in the field of electroplating copper additives for advanced packaging, both domestically and internationally, delving into the types and mechanisms of various additive molecules, including accelerators, inhibitors, and leveling agents. Through in-depth research on these additives, we gain a profound understanding of their specific roles in the electroplating process and the intricate interaction mechanisms among them, providing theoretical support for optimizing the electroplating process. Furthermore, this mini-review also delves into a thorough analysis of the current issues and challenges facing acid copper electroplating, exploring the key factors that constrain the further development of electroplating copper technology. Based on this analysis, we propose several potential solutions and research directions, offering crucial references for the development and application of electroplating copper additives in advanced packaging. In conclusion, this mini-review aims to provide a comprehensive perspective and profound understanding of the development and application of electroplating copper additives through a review and analysis of recent research progress, ultimately aiming to promote the further advancement of advanced packaging technology.

Investigation of α-Fe2O3 catalyst structure for efficient photocatalytic fenton oxidation removal of antibiotics: preparation, performance, and mechanism.

Currently, the surface structure modification of photocatalysts is one of the effective means of enhancing their photocatalytic efficiency. Therefore, it is critically important to gain a deeper understanding of how the surface of α-Fe2O3 photocatalysts influences catalytic activity at the nanoscale. In this work, α-Fe2O3 catalysts were prepared using the solvothermal method, and four distinct morphologies were investigated: hexagonal bipyramid (THB), cube (CB), hexagonal plate (HS), and spherical (RC). The results indicate that the hexagonal bipyramid (THB) exhibits the highest degradation activity towards tetracycline (TC), with a reaction rate constant of k = 0.0969 min-1. The apparent reaction rate constants for the cube (CB), hexagonal plate (HS), and spherical (RC) morphologies are 0.0824, 0.0726, and 0.0585 min-1, respectively. In addition, it has been observed that the enhancement of photocatalytic activity is closely related to the increase in surface area, which provides more opportunities for interactions between Fe2+ and holes. The quenching experiments and electron paramagnetic resonance (EPR) results indicate that the ˙O2, ˙OH and h+ contribute mainly to the degradation of TC in the system. This research contributes to a more comprehensive understanding of catalyst surface alterations and their impact on catalytic performance.

Continuous ultrasonic ozone coupling technology-assisted control of ceramic membrane fouling coupled enhanced multiphase mixing to treat dye wastewater and CFD flow field simulation.

In this study, ozone catalysts (hydrogenation-modified red mud, HM-RM) successfully prepared by hydrogenation-modification of industrial hazardous solid waste red mud (RM) as a raw material in accordance with the viewpoint of treating waste with waste and using waste. Meanwhile, as for the common phenomenon of membrane fouling, uneven distribution of multiphase solid catalysts and ozone in liquids, the addition of ultrasound can not only disperse materials, but also play a role in online cleaning of ceramic membranes and catalysts. The optimum treatment conditions for Rhodamine B (RhB) solution with volume of 2 L and concentration of 40 mg/L were catalyst concentration of 0.4 mg/L, reaction temperature of 45 °C, ultrasonic time of 1 h, ultrasonic intensity of 600 W, removal rate of RhB was up to 90 %. In addition, the computational fluid dynamics (CFD) simulation method was used to investigate the fluid flow between the two gas-liquid phases and the effect of the negative pressure of the membrane pump on the fluid by the analysis of flow, pressure and ozone flux of the ceramic membrane(CM) reaction apparatus. The CFD simulation results showed that at the inlet gas-liquid flow rate of 3 m/s and the negative pressure of 20,000 Pa, the maximum flow rates of CM-1 were 3 m/s, 0.752 m/s for CM-2, and 0.228 m/s for CM-3, respectively. Vortices, which are beneficial to solid-liquid mixing and gas-liquid mass transfer, formed between the suction port CM-1 of CM-1 and the inlets of CM-2 and CM-3. This discovery is consistent with relevant experimental research results. Significantly higher concentrations of both •OH and dissolved ozone were observed in the US/HM-RM/O3 system compared to other systems, indicating the significant improvement in ozone utilization rate through the application of ultrasound. The superiority of the US/HM-RM/O3 device was demonstrated. The real dye effluent was tested under optimum operating conditions and the results showed that COD and TOC were reduced by 81.34 % and 60.23 % respectively after 180 min of treatment. The above research can provide technical support for the treatment of dye wastewater using Ultrasound-enhanced ozone oxidation ceramic membranes.

Comprehensive Study on Mineral Processing Methods and Mineral Technical Economics of Manganese Ore in Chongqing Chengkou.

Chongqing Chengkou manganese deposit is a large carbonate-type manganese deposit in the upper reaches of the Yangtze River, located in Gaoyan Town, Chengkou County, Chongqing. In order to improve the recovery rate of low-grade manganese ore and concentrate grade index, achieve efficient utilization of mineral resources, and sustainable development of Gaoyan manganese ore deposit in Chengkou, Chongqing, China, in this paper, by means of optical microscope analysis, high-resolution X-ray tomography technology, three-dimensional image analysis technology, X-ray diffraction analysis, X-ray fluorescence spectrum analysis, and technical and economic analysis, the occurrence state and process mineralogy of manganese are studied, and the technical and economic analysis of flotation, high-intensity magnetic separation, and gravity separation are carried out. It provides a reference for other mining enterprises to choose the most suitable beneficiation method according to the specific mineral species.

Eddy Current Identification Methods and Applications in the Chemical Industry: A Mini-Review.

As one of the most common fluid patterns in the fluid flow process of chemical production, a vortex has been successfully demonstrated to be a structure that promotes interphase mixing and enhances heat and mass transfer. Therefore, it is essential to reveal the vortex evolution laws in order to realize more efficient and less energy-consuming chemical production. In this Mini-Review, the vortex identification criteria are introduced in detail and categorized according to their development history. The application of vortex identification technology and its application in the chemical industry are explored with a large number of examples. This review enhances our understanding of vortex structures and provides plenty of innovative ideas for the study of chemical industry production.

CFD Simulation Investigation on the Flow Field Distribution Pattern under Different Operating Environment Pressures in a Jet Impingement-Negative Pressure Reactor.

A jet impingement-negative pressure deamination reactor (JI-NPDR) has excellent ammonia removal efficiency. The CFD numerical simulation method based on the Euler-Euler model and the realizable k-ε turbulence model was used to investigate the effect of different negative pressures at the reactor top outlet on the distribution pattern of pressure, velocity, turbulent kinetic energy, and vortex. The results indicate that the overall water flow distribution in the reactor increases in axial cohesion with the increase in negative pressure. The scattered small eddies gradually connect to a large eddy current as a whole, and the small eddies generated in the jet area also become regular and flat with the increase of negative pressures. These findings can provide detailed information for the study of flow patterns in a jet impingement-negative pressure reactor.

Synthesis of CuO x /TiO2 Photocatalysts with Enhanced Photocatalytic Performance.

CuO x /TiO2 co-photocatalysts with various Cu loading contents were synthesized by an impregnation method, and their photocatalytic activities were evaluated by photodegradation of organic pollutants under visible light illumination. The as-prepared CuO x /TiO2 composites exhibited a unique structure, in which CuO x clusters with about 2-3 nm nanocrystals were uniformly distributed on the TiO2 cube. The mesoporous Ti3+/TiO2 substrate with a uniform pore structure greatly improved the uniformity of the loaded Cu, wherein Ti3+ acted as a reducing agent for reducing Cu2+ to Cu+ and Cu0. The reversible process of the Cu species between Cu+ and Cu0 markedly enhanced the photocatalytic activity of the CuO x /TiO2 co-photocatalyst, by promoting the transfer of photogenerated electrons and suppressing the recombination of photogenerated electron and hole pairs. The synergistic effect between CuO x and TiO2 also played an important role in enhancing the photocatalytic activity of the CuO x /TiO2 co-photocatalyst. The results indicated that CuO x /TiO2-1 had the highest photocatalytic efficiency, which was 1.5 times higher than that of the commercial nano-TiO2 P25 under visible light, and demonstrated a good stability even after five recycles. This structural design and the valence control strategy for the Cu atom provide an idea that facilitates the utilization of visible light and the improvement of the photocatalytic activity of TiO2, promoting the practical application of the TiO2 photocatalyst.

NADPH oxidase contributes to the production of reactive oxygen species in Chlorella pyrenoidosa.

Reactive Oxygen Species (ROS) play an important role in oxidative stress and are related to the lipid accumulation in microalgae. Nicotinamide Adenine Dinucleotide Phosphate (NADPH) oxidase can oxidize O2 to O2- ultimately. However, the function of NADPH oxidase and its contribution to the production of the intracellular total ROS are still unclear. In this study, the function of NADPH oxidase in Chlorella pyrenoidosa (C. pyrenoidosa) was investigated by adding activators Ca2+ and NADPH and inhibitors EGTA, LaCl3, DPI and BAPTA of NADPH oxidase. The results show that the addition of activators of Ca2+ or NADPH significantly increased the intracellular concentrations of ROS molecules (H2O2, O2-, and OH·) in C. pyrenoidosa. Moreover, the intracellular ROS level was higher under the nitrogen-deficient and phosphorus-deficient conditions than in control condition, but the addition of the inhibitors (EGTA, LaCl3, DPI, and BAPTA) of NADPH oxidase significantly reduced the intracellular concentrations of H2O2, O2-, and OH·. The study shows that NADPH oxidase actively participated in the production of intracellular ROS in C. pyrenoidosa, demonstrating that NADPH oxidase was another important element in the production of intracellular ROS in addition to mitochondria, chloroplasts and lysozymes in microalgae.

Application of Machine Learning in a Mineral Leaching Process-Taking Pyrolusite Leaching as an Example.

In this study, several machine learning models were used to analyze the process variables of electric-field-enhanced pyrolusite leaching and predict the leaching rate of manganese, and the applicability of those models in the leaching process of hydrometallurgy was compared. It showed that there was no correlation between the six leaching conditions; in addition to the leaching time, the concentrations of sulfuric acid and ferrous sulfate had great influences on the leaching of pyrolusite. The results of the prediction models showed that the support vector regression model has the best prediction performance, with regression index (R 2) = 0.92 and mean square error = 25.04, followed by the gradient boosting regression model (R 2 > 0.85). In this research, machine learning models were applied to the optimization of the manganese leaching process, and the research process and methods were also applicable to other hydrometallurgical processes for majorization and result prediction.

Fluid flow signals processing based on fractional Fourier transform in a stirred tank reactor.

The analysis of fluid flow signals and the characterization of fluid flow behavior are of great importance for two-phase flow studies. In this work, the fractional Fourier transform (FRFT), which was based on the optimum order calculated by stepping search method, was proposed to extract the characteristics of fluid flow signals. Meanwhile, the largest Lyapunov exponent (LLE), which is an indication of the chaotic degree of mixing process, was adopted to quantify fluid flow behavior. The maximum amplitude (MA) and LLE value were taken together to inquire into the relationship between the characteristics of fluid flow signals and the characterization of fluid flow behavior. In addition, differences between the two adjacent values (AD) and the maximum differences (MD) are employed to further analyze the differences in behavioral characterization with MA and LLE. The results show that the MA value performs the same increasing trend as the LLE value when the gas flow rate and agitation speed increase. AD and MD values of the MA are one to two orders of magnitude greater than those of the LLE. The eigenvalues (MA) solved by the FRFT method is facilitates capturing small changes owing to changes in external conditions. These findings can provide new ideas for the extraction and characterization of fluid flow behavior.