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.

Impact of the comprehensive remediation project on hydrological conditions in the lower reaches of the Ganjiang River.

This study undertakes a systematic analysis of the hydrological changes before and after the implementation of the Comprehensive Remediation Project in the lower reaches of the Ganjiang River. It focuses on changes in downstream inflow, ratios of flow distribution, and water levels, as well as water velocity near the gates. The results indicate a significant improvement in the spatial distribution of water resources in the lower reaches of the Ganjiang River. The project enhances the inflow from the northern and southern branches, positively influencing downstream water usage and the ecological environment. Building upon these findings, the study proposes operational recommendations tailored to different hydrological years, such as timely adjustments to the southern branch's water inflow and optimizing flow distribution ratios. This research provides a scientific basis for the implementation and dispatch of comprehensive remediation projects and offers insights into water resource management in similar regions.

Changes in leaf litter decomposition of primary Korean pine forests after degradation succession into secondary broad-leaved forests.

Forest degradation succession often leads to changes in forest ecosystem functioning. Exactly how the decomposition of leaf litter is affected in a disturbed forest remains unknown. Therefore, in our study, we selected a primary Korean pine forest (PK) and a secondary broad-leaved forest (SF) affected by clear-cutting degradation, both in Northeast China. The aim was to explore the response to changes in the leaf litter decomposition converting PK to SF. The mixed litters of PK and SF were decomposed in situ (1 year). The proportion of remaining litter mass, main chemistry, and soil biotic and abiotic factors were assessed during decomposition, and then, we made an in-depth analysis of the changes in the leaf litter decomposition. According to our results, leaf litter decomposition rate was significantly higher in the PK than that in the SF. Overall, the remaining percent mass of leaf litter's main chemical quality in SF was higher than in PK, indicating that leaf litter chemical turnover in PK was relatively faster. PK had a significantly higher amount of total phospholipid fatty acids (PLFAs) than SF during decomposition. Based on multivariate regression trees, the forest type influenced the soil habitat factors related to leaf litter decomposition more than decomposition time. Structural equation modeling revealed that litter N was strongly and positively affecting litter decomposition, and the changes in actinomycetes PLFA biomass played a more important role among all the functional groups. Selected soil abiotic factors were indirectly driving litter decomposition through coupling with actinomycetes. This study provides evidence for the complex interactions between leaf litter substrate and soil physical-chemical properties in affecting litter decomposition via soil microorganisms.

Changes in soil ammonia oxidizers and potential nitrification after clear-cutting of boreal forests in China.

The Korean pine and broad-leaved mixed forests are the most typical and complete ecosystem among the global boreal forests, with extremely important ecological functions. However, few studies on the changes of soil ammonia oxidizers and potential nitrification after clear-cutting of forests are reported. In this study, in contrast to primary Korean pine forests, nitrate (NO3-) was significantly higher in secondary broad-leaved forests, while ammonium (NH4+) was on the contrary. The abundance of ammonia-oxidizing bacteria (AOB) was greatly higher in secondary broad-leaved forests, while levels of ammonia-oxidizing archaea (AOA) were not significantly different between them. The significant differences of community structure of AOA and AOB were observed in different forest types and soil layers. Compared with AOA, community compositions of AOB was more sensitive to forest type. The dominant groups of AOA were Nitrososphaera and Nitrosotalea, and the dominant group of AOB was Nitrosospira, of which Nitrosospira cluster 2 and 4 were functional groups with highly activity. Soil potential nitrification rate (PNR) was higher in secondary broad-leaved forests. Furthermore, PNR and AOB abundance had a significant positive correlation, but no significant correlation with AOA abundance. These results provide insights into the soil nitrogen balance and effects on forest restoration after clear-cutting.

Effects of lumican expression on the apoptosis of scleral fibroblasts: In vivo and in vitro experiments.

Lumican serves an important role in the maintenance of sclera biomechanical properties. However, whether lumican expression is altered in myopia and the mechanisms of action involved are unknown. In the present study, the expression of lumican in cultured scleral fibroblasts and in the scleral tissue of a rat model of form-deprivation myopia was assessed. It was confirmed that diopter was decreased, whereas axial length was increased in modeled eyes relative to normal control eyes, indicating that the model of myopia was successfully established. These pathologic changes were accompanied by the upregulation of lumican and tissue inhibitor of metalloproteinases (TIMP)-2, as well as the downregulation of matrix metalloproteinase (MMP)-2 and MMP-14. The same trends in TIMP-2, MMP-2 and MMP-14 expression were observed when lumican was overexpressed in cultured scleral fibroblasts. Additionally, cell proliferation decreased whereas apoptosis increased compared with those of control cells. Inhibiting lumican expression had no effect on cell proliferation or apoptosis, but stimulated the expression of MMP-2 and MMP-14 while decreasing that of TIMP-2. The results suggested that lumican overexpression contributed to myopia by promoting apoptosis in scleral fibroblasts via the modulation of TIMP-2, MMP-2 and MMP-14 expression.