The leveling of mask and wafer in proximity nanolithography using fringe pattern phase analysis

The fringe pattern phase analysis method is proposed for the leveling of mask and wafer in proximity lithography. The tilt between mask and wafer in the space is reflected in the tilted fringe pattern. The method combining the 2-D Fourier transform and 2-D Hanning window is proposed for processing the tilted fringe pattern. The offset and angle of tilt are extracted through phase analysis. Computer simulation and experiment are both performed to verify this method. The results indicate that the tilt of the mask and wafer in the space can be extracted with high accuracy through this method.     

Leveling and thixotropic characteristics of concentrated zirconia inks for screen-printing

Screen-printing is a cost-effective method for the mass manufacture of zirconia-based solid oxide fuel cells (SOFCs) and oxygen separation membranes. The present work outlines an investigation into the leveling, thixotropic, and screen-printing characteristics of concentrated zirconia inks by a variety of rheological and imaging methods. A combination of viscosity, shear rate jump experiments, creep and recovery analysis, and yield stress measurements were used to assess ink thixotropy. Oscillatory rheometry and scanning electron microscopy/optical microscopy revealed a consistent effect of ethyl cellulose (binder) content upon the thixotropic and leveling characteristics of zirconia inks. While the yield stress (τ ₀), extent of recovery R(%), and rate of recovery (K) increase with increasing binder content, so did the surface roughness and thickness of the screen-printed films. Increasing the binder content not only increases the network strength of the thick films but also leads to increased leveling time. As a result, rheological modifiers are proposed to be necessary to improve the leveling characteristics of zirconia inks without losing the green strength of the thick films.     

Removal of tarnishing and roughness of copper surface by electropolishing treatment

Tarnishing and roughness of copper surface can be removed by electropolishing treatment (EP) imparting a bright and smooth surface at suitable conditions, e.g. current density, time, temperature, and viscosity. It was carried out by using an electrolytic cell containing phosphoric acid 55% as the electrolytic solution. Both copper working electrode and lead counter electrode, and reference electrode (SCE) were connected to a Potentiostat/Galvanostat to allow an electric current to pass through the solution. Some additives such as soluble starch, ethylene glycol, and methanol were added to reduce defects formed on the copper surface during EP process. The results showed that the highest gloss value was obtained by applying electric potential 1.5 V at the passive region of polarization curve. The surface was investigated after EP treatment, where SEM and EDX showed lower roughness in case of addition of both soluble starch and ethylene glycol more than methanol. Moreover, AFM analysis showed the lowest roughness in case of soluble starch more than other additives.     

有机载体对厚膜电子浆料流平性的影响

用TG-DTA16分析仪对用有机载体A及B配制的铝浆挥发等特性进行分析;采用TR101袖珍表面粗糙度仪对烧渗后的铝导电成层的表面状态进行测量。结果表明,用乙基纤维素-松油醇-二乙二醇丁醚为有机载体,浆料的流平性优异,膜层光滑无孔洞,烧成膜的表面粗糙度分别为表面轮廓的算术平均偏差Ra为0.2μm,表面轮廓的最大高度Rz为1μm。     

基于多酯头基的“油-二氧化碳两亲分子”设计及其助混规律

Miscibility between oil and supercritical carbon dioxide (scCO₂) phases has attracted significant attention in the field of oil recovery because it can be utilized in miscible gas displacement of oil, achieving nearly 100% recovery efficiency. The high recovery efficiency of miscible CO₂ flooding originates from the valuable heavy components of oil and CO₂ gas phase forming a homogenous phase with high mobility in the oil-scCO₂ miscible system. However, the high pressure required for oil-scCO₂ miscibility is a nontrivial obstacle for practical applications of scCO₂ flooding recovery. Therefore, it is important to develop assist-miscible agents to lower the necessary miscibility pressure. In oil and water systems, well-developed amphiphiles (such as surfactants) have shown great promise for reducing the interfacial tension and maintaining the stability of the emulsion system. Therefore, "oil-CO₂ amphiphiles" that can assist the miscibility between oil and scCO₂ have been proposed. Among potential oil-scCO₂ amphiphiles, a series of polyester-based oil-CO₂ amphiphiles with esters as the CO₂-philic groups and long carbon chains as the oil-philic groups were prepared. The polyester-based oil-CO₂ amphiphiles, acting as assist-miscible agents, showed great ability to lower the needed miscibility pressure. A visualized miscible method was used to examine the efficiency of the assist-miscible agents with white oil and kerosene as the oil phase. The height of the oil phase inside the chamber was measured through a glass window to monitor the miscibility with increasing CO₂ pressure. When the height of the oil reached the top of chamber, the oil filled the entire space, indicating miscibility. Using this method, the following conclusions could be drawn: First, amphiphiles with more ester groups exhibited stronger CO₂-philicity, providing stronger ability to dissolve carbon dioxide. Second, amphiphiles with hydrocarbon chain lengths of 16 carbons exhibited the optimal assist-miscible efficiency. Third, greater differences between the oil and scCO₂ phase showed more obvious differentiation among amphiphiles, showing the leveling and differentiating effect of oil. The temperature range of 50–80 ℃ did not influence the assist-miscible efficiency of the polyester-based amphiphiles. The best miscibility-assisting performance was obtained with CAA8-X, which contains eight ester groups and a palmitic acid chain. CAA8-X at a concentration of 1% (w, mass fraction) lowered the miscibility pressure in the white oil-scCO₂ system by 16.04%. Amphiphiles with polyether (PEO) groups also showed excellent assist-miscible efficiency. The findings presented herein extend the concept of "amphiphilicity" from oil-water phases to oil-scCO₂ phases and have the potential to guide future studies regarding scCO₂ flooding in actual CO₂ flooding oil recovery. Moreover, for other two-phase systems, according to the general amphipathic law and particular system parameters, it should be possible to design the optimal "amphiphiles".