1,721,037 research outputs found

    Effects of wetting ability of plating electrolyte on Cu seed layer for electroplated copper film

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    [[abstract]]This work examines the impact of the wetting ability of a plating electrolyte on the Cu seed layer on copper electroplating performance. The contact angle of the electrolyte on the Cu seed is highly sensitive to additive decomposition in the electrolyte, as well as being sensitive to Cu seed self-annealing. The contact angle of the electrolyte decreases in the presence of polyethylene glycol (PEG), which forms complexes with chloride ions and is absorbed on the Cu surface during plating. However, the consumption of the additives, particularly that of chloride ions, degrades this adsorption. Additionally, the increase in Cu-seed surface roughness owing to self-annealing also reduces electrolyte wettability, compared to the as-received Cu-seed layer. The poor wettability can be improved with additional rinsing. The x-ray photoelectron spectroscopy (XPS) spectrum demonstrates that the Cu surface was covered with a native cupric-hydroxide layer after rinsing, which was hydrophilic (as in the aqueous-plating bath) and had improved wettability. This study also correlates the contact angle with the trapped defects in the electroplated film, which in turn influence the electrical characteristics of the interconnection. The experimental results show that the poor wettability of the plating electrolyte on the Cu seed significantly influences the fluctuations of the Cu interconnect resistance. This conclusion is valuable in designing Cu damascene processes. (C) 2004 American Vacuum Society.[[note]]SC

    A new relevance feedback technique for iconic image retrieval based on spatial relationships

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    [[abstract]]Due to the popularity of Internet and the growing demand of image access, the volume of image databases is exploding. Hence, we need a more efficient and effective image searching technology. Relevance feedback technique has been popularly used with content-based image retrieval (CBIR) to improve the precision performance, however, it has never been used with the retrieval systems based on spatial relationships. Hence, we propose a new relevance feedback framework to deal with spatial relationships represented by a specific data structure, called the 2D B(e)-string. The notions of relevance estimation and query reformulation are embodied in our method to exploit the relevance knowledge. The irrelevance information is collected in an irrelevant set to rule out undesired pictures and to expedite the convergence speed of relevance feedback. Our system not only handles picture-based relevance feedback, but also deals with region-based feedback mechanism, such that the efficacy and effectiveness of our retrieval system are both satisfactory. (C) 2008 Elsevier Inc. All rights reserved.[[note]]SC

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    Copper surface protection with a completely enclosed copper structure for a damascene process

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    [[abstract]]As integrated circuit manufacture moving to copper interconnection for the most advanced products, protection of copper (Cu) surfaces becomes a major challenge for the back-end-of-line manufacturing process. The damages on Cu, such as Cu corrosion and oxidation, are often observed on wafers when exposing bare Cu surface in the presence of moisture and/or acidic gases. Furthermore, the Cu oxide results in poor adhesion both at Cu/barrier layer and Cu/stop layer interfaces. In this work, a novel Cu dual damascene structure which completely encloses the Cu surface with a tantalum nitride layer is presented. This capping layer avoids the Cu corrosion and oxidation due to its ability to keep moisture and acid off and away from the Cu surface. (C) 2003 Elsevier Science B.V. All rights reserved.[[note]]SC

    Synthesis and Properties of Water-Soluble Core–Shell–Shell Silica–CdSe/CdS–Silica Nanoparticles

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    [[abstract]]This paper describes the synthesis of highly water-soluble and fluorescent core–shell–shell silica–CdSe/CdS–silica nanoparticles (CSS silica–QDs–silica NPs). We used cadmium nitrate and 1,1-dimethyl-2-selenourea precursors to synthesize CdSe quantum dots (QDs)in aqueous solution under simultaneous illumination with a diode-pumped solid state green laser and a Xe–Hg lamp. After passivation of the CdSe QDs with CdS, the CdSe/CdS QDs were then conjugated covalently to (3-mercaptopropyl)trimethoxysilane (MPS); we call these nanoparticles "MPS-QDs". We mixed the MPS-QDs with tetraethoxysilane (TEOS), ethanol, and NH3. By controlling the concentrations of the reagents, the stirring speed, and the reaction time, we synthesized CSS silica–QDs–silica NPs having sizes ranging from 75 to 190 nm. The incubation time for preparing the MPS-QDs and their concentrations are important parameters in determining the morphologies of the CSS silica–QDs–silica NPs. When we mixed 50 nM MPS-QDs, 1.1 mM TEOS, and 78 mM NH3 and reacted them at a stirring speed of 750 rpm, we obtained 85-nm-diameter CSS silica–QDs–silica NPs having a QD shell thickness of about 20 nm. The CSS silica–QDs–silica NPs provide a strong photoluminescence intensity (quantum yield 88%)and exhibit enhanced stability both photochemically and in high-conductivity media (e.g., 1.0 M NaCl)

    Variations on the Author

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    “Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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