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The purpose of this study is to investigate the effect of the different deposition mediums on the adhesion and removal of particles. Polystyrene latex ͑PSL͒ particles ͑50 m͒ are deposited on thermal oxide and silicon nitride coated silicon wafers using different suspension mediums: air, isopropyl alcohol ͑IPA͒, and deionized water and then removed in a dry environment. The results show that PSL particles deposited on oxide are easier to remove than those on nitride due to a higher van der Waals force in all deposition mediums. In addition, dry particles deposited in air are much easier to remove than those desposited in a liquid medium. When particles are deposited from a liquid suspension, a liquid meniscus is formed between the particle and the substrate, resulting in a capillary force. The capillary force induces a plastic deformation for soft particles such as PSL, which increases the contact area between the particle and the substrate, making them more difficult to remove. The liquid meniscus evaporates shortly after it is exposed to either a dry air environment or vacuum; however, the plastic deformation of particles would take place mainly due to the initial adhesion force in addition to the short time exposure of the capillary force. © 2010 The Electrochemical Society. ͓DOI: 10.1149/1.3377090͔ All rights reserved. Particle adhesion is one of the main causes of yield loss in the semiconductor industry 1 because particles can cause short-circuit or open circuit; 2 however, particle adhesion has other useful applications. For example, the adhesion of drug particles to specific sites is important to the pharmaceutical industry.3 In xerography, the ability to transfer toner particles successfully from the photoconductor to the receiver requires an understanding of the mechanisms of particle adhesion. 4,5 In nanomanufacturing, 6 researchers have made nanowires out of nanoparticles using directed assembly. [6][7][8] Although there are many published studies on the adhesion and removal of particles, there has been a dearth of studies addressing the effect of the different deposition mediums on particle adhesion and removal. In this paper, three different deposition mediums, air, isopropyl alcohol ͑IPA͒, and deionized ͑DI͒ water, were used to deposit polystyrene latex ͑PSL͒ particles on thermal oxide and silicon nitride wafers. These particles were removed using a spinner in air to observe the effect of deposition mediums on particle removal efficiency ͑PRE͒. Theoretical BackgroundAdhesion force and adhesion moment.-The first major adhesion force is the omnipresent van der Waals force. Without any external load applied on the particle, the attractive van der Waals force brings the particle into contact with the surface when a particle is within the force's range. A liquid meniscus can form between the particle and the substrate when either a liquid film or a high humidity is present. The resulting capillary force makes a large contribution to the total adhesion force. In this paper, we focus on these van der Waal...

Supercritical and vapor‐phase reactions of oxidizers and fuels under pressure are of commercial interest. Because mixtures of propane and nitrous oxide have the potential to be explosive, a model mixture was studied with the intent of defining safe operating boundaries. This work investigated the nitrous oxide/propane oxidant/fuel system, diluted with the inert solvent carbon dioxide, and a catalyst as an accelerant, to determine the safe operating regions for the oxidation reaction. Using an ARC® calorimeter for the evaluations, variables included initial system density, catalyst, and mixture compositions. Density of the system ranged from 0.05 to 0.62 g/cm3. A number of catalysts were investigated with 10% Pd on carbon being the most active. Strongest reactivity was observed when the mixture was stoichiometric to the complete combustion products of nitrogen, carbon dioxide, and water. Three distinct regions of reactivity were observed: mild reactivity (starting at the sensitivity of the ARC of dT/dt = 0.02 to about 0.1° C/min); strong exothermic reaction (dT/dt ≅ 1° C/min); and flammable and/or explosive (a distinct and substantial jump in dP/dt in <1 s). As a result, a boundary has been proposed for safe mixtures of nitrous oxide, propane, and carbon dioxide, and a basis for determining safe operating compositions for other systems. The computed adiabatic reaction temperature was used to correlate the experimental results to establish the boundary for safe operation. © 2005 American Institute of Chemical Engineers Process Saf Prog, 2005

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A strong chemiluminescence (CL) response is observed when potassium permanganate solution is injected into basic luminol solution. When the CL reaction terminates, subsequent injection of Hg2+ solution into the reaction mixture results in a new CL reaction. Based on the post-catalytic enhancement effect of Hg2+ on the potassium permanganate-luminol system in basic media, a fast and simple CL-coupled flow injection analysis for the determination of Hg2+ was developed. In optimum conditions, CL intensity is proportional to Hg2+ concentration over the range 1.0 x 10(-8)-1.0 x 10(-5) g/mL, with a detection limit of 2.0 x 10(-9) g/mL. The relative standard deviation (RSD) is 3.6% for 1.0 x 10(-7) g/mL Hg2+ (n = 11). After pretreatment with sulphydryl cotton fibre, environmental water samples were analysed by the proposed method for total mercury determination with satisfactory results. The results were in good agreement with those given by hydride generation-cold vapour atomic absorption spectrometry (HG-CVAAS).