A High Copper Concentration Copper-Quadrol Complex Electroless Solution for Chip Bonding Applications.

This article presents a novel bonding method for chip packaging applications in the semiconductor industry, with a focus on downsizing high-density and 3D-stacked interconnections to improve efficiency and performance. Microfluidic electroless interconnections have been identified as a potential solution for bonding pillar joints at low temperatures and pressures. However, the complex and time-consuming nature of their production process hinders their suitability for mass production. To overcome these challenges, we propose a tailored plating solution using an enhanced copper concentration and plating rate. By eliminating the need for fluid motion and reducing the process time, this method can be used for mass production. The Taguchi approach is first used to optimize the copper-quadrol complex solution with the plating rate and decomposition time. This solution exhibits a copper concentration that is over five times higher than that of conventional solutions, a plating rate of 22.2 µm/h, and a decomposition time of 8 min on a Cu layer substrate. This technique enables Cu pillars to be successfully bonded within 7 min at 35 °C. Planarizing the pillar surface yields a high bonding percentage of 99%. Mechanical shear testing shows a significant fracture strength of 76 MPa.

Dislodgement of Hydrogen Bubbles in Microchannels with Embedded Pillars: An Analytical, Experimental, and Numerical Study.

Microchannels with integrated pillars have enhanced the production capabilities and performance of various applications due to their high surface-to-volume ratio. However, emerging gas bubbles can become trapped, potentially limiting the functionality or efficiency of the device when scaled down to the low-micrometer scale. Understanding the conditions required to dislodge these bubbles is thus critical for optimizing microfluidic devices with complex physical behaviors. Here an analytical model is presented that outlines the dislodgment conditions and driving forces for such gas-liquid flows. These terms are derived from the gas-liquid interface properties, geometry, and processing parameters. As the density of the pillar arrangement is scaled down, the resistance to bubble dislodgment typically increases. Nevertheless, the bubble is compelled to dislodge at lower pressure loads when critical volumes are reached. This newly discovered effect is particularly noticeable in densely packed arrays and can be explained by the interplay of increased surface tension, geometrical restrictions, and volume-preserving forces. The analytical terms and effects are validated through novel experimental and numerical methods tailored for microchannels in the low-micrometer scale, showing strong agreement.

Hydrothermally constructed AgWO4-rGO nanocomposites as an electrode enhancer for ultrasensitive electrochemical detection of hazardous herbicide crisquat.

The advancements in electrode materials with high efficiency has been prioritized to effectively monitor the presence of harmful pesticides concerning the environment. In such a way, we hydrothermally constructed a hybrid AgWO4-rGO nanocomposites for the rapid electrochemical detection of crisquat (CQT). The structural, compositional, morphological and topographical characterization for AgWO4-rGO nanocomposites is thoroughly performed to understand its electrocatalytic properties. The AgWO4-rGO nanocomposites are used as an electrode enhancer (rGO@AgWO4/GCE) for the electrochemical investigations towards CQT detection. The results indicated that the rGO@AgWO4/GCE possessed an excellent catalytic activity with a wide linear detection range 1-1108 µM coupled with an ultrasensitive limit of detection (LOD) 0.0661 µM for electrochemical CQT detection. The rGO@AgWO4/GCE CQT sensor also expressed remarkable sensitivity of 0.6306 µAµM-1cm-2 in addition to good selectivity and reproducibility. Furthermore, the commercial CQT, river water, tap water and washed vegetable water are used as a representative for real world analysis using rGO@AgWO4/GCE and results are highly appreciable for the real time CQT detection. Our work proposes a novel hybrid rGO@AgWO4 nanocomposites reinforced electrodes for ultra-trace level CQT detection with good reliability and can be advocated for real time detection of pesticides.

Bifunctional bimetallic heterojunction material based on Al2O3/ZnO micro flowers for electrochemical sensing and catalysis.

We report the synthesis, characterization, electrochemical sensing and catalytic capability of the bimetallic heterojunction Al2O3/ZnO micro flowers (AZ MFs). In order to prepare this bifunctional material, the facile hydrothermal process was adopted. The material was thoroughly characterized for the crystal structure and morphology with Powder XRD, XPS and FE-SEM. The investigation of electrochemical sensing was done using hydroquinone (HQ) and the chemical catalysis was using rhodamine B (RhB) with our bimetallic Al2O3/ZnO micro flowers as these are harmful industrial pollutants. The process parameters like the influence of scan rate and pH was efficiently optimized for the electrochemical detection of HQ and kinetics for the time dependent catalytic degradation of RhB dye. The linear relationship between the peak current and the concentration of HQ was found to be in the range of 0.125-20.25 µM with an impressive detection limit of 11.2 nM. In the chemical catalytic degradation of the RhB dye, our bimetallic material thrived well during the reaction and degraded the material in 10 min. The performance of bimetallic Al2O3/ZnO micro flowers towards HQ detection and RhB degradation shows good stability, reproducibility and it can be efficiently utilized to treat the environmental pollutants.