bluuebunny/crossref_metadata_2025 huggingface dataset:
Primary Palmoplantar Kaposi's Sarcoma: An Unusual Presentation
Authors: Al Zolibani Abdullateef A. , Al Robaee Ahmad A.
Published: February 2007

A 65‐year‐old diabetic Saudi Arabian man taking glibenclamide for 9 years presented with painful reddish patches and plaques involving the palms and soles of 6 months' duration. These lesions started as small faint purple‐red macules and gradually increased in number and size. The patient did not seek any medical advice other than for these painful lesions. His medical history was insignificant. On examination, the patient had multiple, discrete, dull red‐to‐violaceous and tender patches and plaques of variable sizes on both palms and soles (Figure 1 and xFigure 2). His mucous membranes, scalp, and nails were normal. A systemic clinical examination was unremarkable other than an amputation of the distal phalanx of the left index. Result of routine laboratory investigations including complete blood cell count, liver and renal function tests, and chest x‐ray were normal. An HIV test was negative. A punch skin biopsy taken from the left palm showed acanthosis and spongiosis in the epidennis. The dennis showed a large number of dilated, medium‐sized capillaries with scanty extravasated red blood cells, marked infiltration of lymphocytes and histiocytes, and a few plasma cells (Figure 3 and Figure 4). Immunohistochemistry results were positive for CD34 and CD68. Polymerase chain reaction for human herpesvirus 8 was also positive. The treatment options, including cryotherapy and intralesional chemotherapy, were discussed with the patient but, unfortunately, he did not return for follow‐up.

Multiple, discrete, dull red‐to‐violaceous patches and plaques on both hands

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The right foot showing multiple, discrete, dull red‐to‐violaceous patches and plaques

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Punch skin biopsy from the left palm showing a large number of dilated mediumsized capillaries with scanty extravasated red blood cells, marked infiltration of lymphocytes and histiocytes, and a few plasma cells (hemotoxylin and eosin stain; original magnification ×20)

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A close‐up view of the dermis showing a large number of dilated medium‐sized capillaries with scanty extravasated red blood cells, marked infiltration of lymphocytes and histiocytes, and a few plasma cells (hemotoxylin and eosin stain; original magnification ×40)

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Hailey‐Hailey
Authors: McKibben LT Julie , Smalling Charles
Published: February 2007

An 18‐year‐old white man with a “rash” on his forehead, neck, and upper part of the back for more than 5 years presented to the dermatology clinic complaining of chronic irritation and burning in these locations. He first became aware of the problem while playing football when he noticed that areas where his shoulder pads and helmet contacted his skin were red and irritated. He was treated by his primary care physician for contact dermatitis, and the areas partially responded to mild topical corticosteroids and emollients. Symptomatic worsening of the lesions, including increasing burning pain and a clear discharge, subsequently led to a primary care diagnosis of impetigo, which was treated with oral antibiotics. Again, there was partial improvement while taking the antibiotics but no resolution, and the areas of involvement continued to expand. Exacerbations over the next few years were diagnosed as tinea, psoriasis, and seborrheic dermatitis, with the patient reporting temporary and incomplete relief following treatment for all of the above diagnoses.
Nanocrystalline Oxalate/Carbonate Precursors of Ce and Zr and Their Decompositions to CeO2 and ZrO2 Nanoparticles
Authors: Vaidya Sonalika , Ahmad Tokeer , Agarwal Suman , Ganguli Ashok K.
Published: February 2007

The oxalate and carbonate precursors of cerium and zirconium have been prepared using reverse micelles as nanoreactors. Cerium oxalate precursor on thermal decomposition leads to a mixture of nanorods and nanoparticles of cerium oxide (nanoparticles of 10 nm and nanorods with 7 nm diameter and 30 nm length). Cerium oxide with crystallite size of 10 nm was obtained from cerium carbonate precursor. Monodispersed nanoparticles of zirconia with an average size of 3–5 and 12 nm were obtained from the oxalate and carbonate precursor, respectively. Detailed dielectric properties of sintered discs of nanocrystalline ceria and zirconia have been studied with variation of frequency and temperature.
Role of Orthopedic Implants and Bone Morphology in the Identification of Human Remains
Authors: Simpson Ellie K. , James Ross A. , Eitzen David A. , Byard Roger W.
Published: February 2007

ABSTRACT: When conventional methods of identification, such as visual recognition and dental comparison, cannot be used to identify a deceased person, it becomes necessary to consider alternative methods. The presence of an orthopedic implant in a body may assist identification if ante‐mortem medical records are available for comparison. Another method of identification involves comparison of ante‐mortem and postmortem radiographs. Eight cases are reported from Forensic Science SA where the presence of orthopedic implants and/or ante‐mortem radiographs were used to try to establish identification. In six cases, positive identification was established, and in two cases with upper limb orthopedic implants, the bones remained unidentified. Manufacturers were unable to provide any information about the distribution and use of the implants that could be of use with identification, as there are no requirements in Australia for individual medical implants to be tracked. Such a system has the potential to aid postmortem identification if serial codes were etched onto implants that could then be traced to manufacturers, surgeons, and recipients of these devices.
Management of Cardiovascular Risk in Patients With Type 2 Diabetes Mellitus as a Component of the Cardiometabolic Syndrome
Authors: Ferdinand Keith C.
Published: February 2007

Heart disease and stroke are the most life‐threatening consequences of diabetes mellitus, with mortality rates up to two to four times higher for persons with diabetes vs. those without and accounting for up to 65% of deaths. The cardiometabolic syndrome is a potent indicator of future risk of type 2 diabetes and concomitant increased potential for cardiovascular morbidity and mortality. Pharmacologic treatment is usually necessary to improve blood pressure and lipids, thereby decreasing the risk of cardiovascular disease. The reduction of cardiovascular and renal risk with type 2 diabetes and elevated blood pressure are compelling indications for thiazide diuretics, â blockers, angiotensin‐converting enzyme inhibitors, angiotensin II receptor blockers, and calcium channel blockers. Nevertheless, most patients with type 2 diabetes and elevated blood pressure will require two or more agents to lower blood pressure to the recommended goal of <130/80 mm Hg, and combination therapy may be beneficial. In patients with the cardiometabolic syndrome without type 2 diabetes, the present goal is to maintain BP <140/90 mm Hg, although recent data suggest potential decrease in the progression of prehypertension to hypertension with antihypertensive medication. Furthermore, blockers of the renin—angiotensin system may actually prevent newonset diabetes. It is reasonable for patients with type 2 diabetes and cardiovascular disease to achieve an optional low‐density lipoprotein cholesterol (LDL‐C) goal <70 mg/dL, and statin therapy should be considered regardless of baseline LDL‐C level. In patients with the cardiometabolic syndrome without type 2 diabetes and calculated moderately high‐risk status (two or more risk factors; 10‐year risk, 10%–20%), the present goal for LDL‐C is <130 mg/dL, with perhaps a therapeutic option of <100 mg/dL, and in patients with the cardiometabolic syndrome at lower risk, the LDL‐C goal remains <160 mg/dL. Multifactorial management must be utilized to prevent progression of cardiovascular risk with the cardiometabolic syndrome and the ravages of cardiovascular disease in persons with type 2 diabetes, including antiplatelet therapy with aspirin.
Microalbuminuria and Proximal Tubule Remodeling in the Cardiometabolic Syndrome
Authors: Hayden Melvin R. , Chowdhury Nazif A. , Witte Lauren , Sowers James R.
Published: February 2007

Microalbuminuria is a simple screening test that is not only associated with an increased risk of progressive renal insufficiency, but also an increased risk of cardiovascular disease and stroke in the cardiometabolic syndrome. The role of oxidative stress, inflammation, and cellular‐extracellular matrix remodeling fibrosis is very important, and the authors have previously observed that albuminuria is related, in part, to loss of the integrity of the glomerular filtration apparatus. The proximal tubule may play a more important role than previously thought, as it is estimated that in health this portion of the nephron reabsorbs 5–8 g of albumin that normally leaks through the glomerulus on a daily basis. Recently, the authors have made important preliminary observational findings regarding proximal tubule microvilli remodeling and oxidative stress, which may help to explain microalbuminuria. These observations suggest that albuminuria is associated with proximal tubule injury, as well as loss of integrity of the glomerular filtration barrier in association with obesity and insulin resistance.
Myocardial Myocyte Remodeling and Fibrosis in the Cardiometabolic Syndrome
Authors: Hayden Melvin R. , Chowdhury Nazif , Govindarajan Guru , Karuparthi Poorna R. , Habibi Javad , Sowers James R.
Published: February 2007

Myocardial cellular and extracellular matrix remodeling are important in the development of left ventricular hypertrophy and are essential for the adaptive and maladaptive changes associated with the cardiometabolic syndrome. This brief review of myocyte remodeling also presents preliminary observational findings regarding myocardial adaptive hypertrophy remodeling, including an increase in mitochondria and capillaries, convolutions and lengthening of intercalated discs, the addition of sarcomeres, thickened Z lines, and the novel presence of pericapillary fibrosis (in addition to perivascular arteriolar fibrosis). The 11‐week‐old TG(mREN‐2)27 transgene rat model of tissue angiotensin II overexpression, which develops hypertension and insulin resistance, was chosen to examine both myocyte hypertrophy and extracellular matrix fibrosis. This review and the preliminary observational findings may provide the clinician and researcher a better understanding of remodeling changes in the myocardium and ultimately foster earlier recognition and therapeutic interventions.
Application of Recent Definitions of the Metabolic Syndrome to Survey Data From the National Cholesterol Education Program Evaluation Project Utilizing Novel E‐Technology (NEPTUNE II)
Authors: Deedwania Prakash C. , Maki Kevin C. , Dicklin Mary R. , Stone Neil J. , Ballantyne Christie M. , Davidson Michael H.
Published: February 2007

This was a post hoc analysis of data collected in the National Cholesterol Education Program (NCEP) Evaluation Project Utilizing Novel E‐Technology II (NEPTUNE II) survey conducted in 2003. Among 4885 dyslipidemic patients receiving lipid management in the United States, estimates of the prevalence of the metabolic syndrome according to the 2001 NCEP Third Adult Treatment Panel (ATP III), the 2005 American Heart Association/National Heart, Lung, and Blood Institute Scientific Statement, and the 2005 International Diabetes Federation definitions were 55%, 62%, and 63%, respectively. Metabolic syndrome prevalence among patients with coronary heart disease and risk equivalents was 69%, 74%, and 74%, according to these respective definitions. Notably, in the coronary heart disease and risk equivalents category, the prevalence was similar to that of the multiple risk factor category when patients with diabetes mellitus were excluded from the analysis (46% by ATP III). The metabolic syndrome is common in patients receiving lipid‐lowering therapy in an office‐based setting. Three recent definitions resulted in similar estimates of its prevalence.
Timed stance performances reflect differences in age, prevalence of comorbidities, medication use, fall history and activity level: Early screening for balance loss is indicated
Authors: Choy Nancy L Low , Brauer Sandra G , Nitz Jennifer C
Published: February 2007

Objectives: To determine if 10‐second trials of bilateral and one‐legged stance measures detected balance loss and influence of known risk factors for falls in women aged 20–80 years.

Methods: 456 healthy adult women attempted 10‐second trials of bilateral stance (firm and foam surfaces) and one‐legged stance, with eyes open (EO) and eyes closed (EC). Data for age, co‐morbidities, medication use, fall history and activity level were compared for three categories of stability: (i) stable: all trials completed; (ii) unsteady: completed/failed one to two trials; and (iii) failed all trials.

Results: Bilateral stance on foam (EC) and one‐legged stance (EO) yielded low failure rates for women older than 50 years (up to 15% categorised as unsteady and 6% as unstable). Compared to stable women, the unsteady and unstable women were older (P < 0.001) reported more co‐morbidities, using more medications (P < 0.001), more falls (P < 0.05) and less activity (P < 0.05).

Conclusions: Women older than 50 years who fail 10‐second trials of bilateral stance (foam EC) and one‐legged stance (EO) should be referred for education and fall prevention intervention.
Characterization of a novel HLA‐DRB1*04 allele (DRB1*0460) in the Italian population
Authors: Frison S. , Rinaldini C. , Pagoda M. , Brambilla C. , Poli F.
Published: February 2007

We report the identification of a novel HLA‐DRB1*04, officially named DRB1*0460. It was detected during performing HLA‐DRB1 high resolution typing by DNA sequencing‐based method. The exon 2 nucleotide sequence of DRB1*0460 is identical to that of DRB1*040301 except at codon 63 (AGC→AAC), changing the encoded serine to asparagine.
Nanoscale optical imaging of pigment particles in paint with near-field scanning optical microscopy
Authors: Clark Beverly , Gurguis Gamil , Hallen H. D.
Published: February 2007

The distribution of pigment at the nano to micron scale illuminates the length scale of failure in paint samples. The authors use optical and topographical images from near-field scanning optical microscopy (NSOM) to compare a high quality paint sample with one that fails a standard quality control test based on visual inspection. NSOM provides the required nanometer to micrometer mesoscopic regime resolution and range, combined with simultaneous topographic and optical information. Features such as pigment clumping and pigment density fluctuations are simultaneously analyzed. The two types of samples are distinguished by fluctuations at different length scales. The authors observed individual pigment particles near the polymer surface of both samples.
Remarkably efficient acid generation in chemically amplified resist from quantum chemistry modeling
Authors: Granovsky Alex A. , Bochenkova Anastasia V. , Suetin Nikolay , Fryer David , Singh Vivek
Published: February 2007

The authors apply methods of quantum chemistry to obtain information on the equilibrium geometrical structure, IR and UV spectra of the photoacid generator (PAG) di(phenylsulphonyl) diazomethane (DPSD) and products of its photoinduced decomposition, and UV spectra of polyhydroxystyrene (PHOST) and poly(4-t-butoxycarbonyloxystyrene) (PTBOCST), and to characterize a viable alternative path for photoinduced decomposition of DPSD in PHOST-like resists. In contrast with previously published sulphone-based chemistry, the newly suggested path for acid generation results in formation of up to two acid molecules per single PAG molecule. The theoretical results are quantitatively compared with available experimental data.
Electrical, photoelectrical, and luminescent properties of doped p-type GaN superlattices
Authors: Polyakov A. Y. , Smirnov N. B. , Govorkov A. V. , Shcherbatchev K. D. , Bublik V. T. , Voronova M. I. , Dabiran Amir M. , Osinsky A. V. , Pearton S. J.
Published: February 2007

Electrical photoelectrical, and microcathodoluminescence properties were measured on doped p-GaN superlattices prepared by molecular beam epitaxy on c-plane sapphire substrates. The photosensitivity of such superlattices is at least two orders of magnitude higher and the microcathodoluminescence intensity is about five times lower than for similarly grown uniformly doped p-GaN films. The difference is explained by the spatial separation of the photoexcited electrons and holes by the superlattice potential. The sheet carrier concentration in the superlattice is shown to be several times (6.6×1012cm−2 vs 2×1013cm−2) lower and the effective hole mobility almost two times higher (20cm2∕Vs vs 12cm2∕Vs) than for bulk p-GaN samples with similar doping.
Critical impact of mask electromagnetic effects on optical proximity corrections performance for 45nm and beyond
Authors: Azpiroz Jaione Tirapu , Rosenbluth Alan E. , Lai Kafai , Fonseca Carlos , Yang Da
Published: February 2007

Numerous studies have addressed the challenges ahead in optical lithography due to electromagnetic effects in photomasks (so-called emf effects), which arise from the complex interaction of the illumination with mask topography whose size now approaches the wavelength. As design critical dimensions shrink, the electromagnetic response of the reticle becomes a complicated function of the incident polarization with serious impact to printed critical dimension (CD) on the wafer. A number of modeling techniques are available to approximately account for emf in the process models employed during optical proximity correction calculations, with small to moderate runtime penalty. Among them are simple mask CD bias, the boundary layer [J. T. Azpiroz et al., Proc. SPIE 5040, 1611 (2003)], the domain decomposition method [K. Adam and A. Neureuther, Proc. SPIE 4562, 1051 (2001)], and techniques based on the geometrical theory of diffraction [G. K. Chua et al., Proc. SPIE 5377, 1267 (2004); A. Khoh et al., J. Opt. Soc. Am. A 21, 959 (2004)]. In this article several of these techniques are benchmarked in terms of accuracy and range of applicability. Results are compared against rigorous electromagnetic simulations.
Multiple replication of three dimensional structures with undercuts
Authors: Möllenbeck S. , Bogdanski N. , Wissen M. , Scheer H.-C. , Zajadacz J. , Zimmer K.
Published: February 2007

Three dimensional linear structures with definite undercuts of different sizes were replicated in the first step in an elastomeric material and, in the second replication step, in a negative tone resist. Undercut masters for the first step were prepared from Si by laser ablation and anisotropic wet etching. For the second step the elastomeric replica, featuring the inverse undercut, served as a master. The first replication was performed by molding or imprinting, where the prepolymer of the elastomer was cross-linked within the master in an oven or in a thermal press, respectively. The second replication of the undercut elastomeric structures into the negative tone resist was performed successfully by molding. Comparison of the Si masters with the second replication revealed shrinkage-induced differences. Undercuts of up to 60% of the overall pattern width were successfully replicated.
Advance static random access memory soft fail analysis using nanoprobing and junction delineation transmission electron microscopy
Authors: Chang Wen-Tung , Hsieh Tsung-Eong , Zimmermann Gunnar , Wang Lars
Published: February 2007

Nanoprobing was used to analyze the soft cell failure of submicron static random access memory (SRAM) at cell level by means of a Zyvex S100 nanomanipulator system inside a scanning electron microscopy and a multiprobe atomic force probe system, respectively. For the 256Kbyte dual-port SRAM block, the failure areas exhibit very weak positive-channel field effect transistor drain currents of several magnitudes below the target values, while the drain currents of negative-channel field effect transistor cell transistors are in the expected range. A junction delineation or junction stain was applied to transmission electron microscopy samples to delineate areas with different doping levels so as to make the fail sites visible. Due to the difference in etching behavior of the fail and a reference area, missing lightly doped drain extensions and a partially blocked source/drain implantation were identified as the failure mechanisms.
Large deformation analysis of suction caisson installation in clay
Authors: Zhou Hongjie , Randolph Mark F
Published: February 2007

Large deformation finite element (LDFE) analyses were performed to study the installation of caissons by suction and jacking in normally consolidated clay. The penetration of the caisson wall was modelled between depths of one and four diameters using an axisymmetric LDFE approach, which falls in the category of arbitrary Lagrangian–Eulerian (ALE) methods. The results allowed quantification of differences in the behaviour of caissons installed entirely by jacking compared with a combination of self-weight and suction as is used in the field. For jacked installation, over the penetration range of one to four diameters, the proportion of caisson wall accommodated by inward soil flow reduced from around 45% at the start to zero at about four diameters embedment; by contrast, the proportion for suction installation stayed essentially constant, oscillating around 65% through the depth of penetration. This difference was also evident in the local incremental displacements of the soil beneath the caisson tip. During continuous penetration, the induced increases in radial and mean total stresses around the caisson wall are some 10%–15% smaller for suction installation than for jacked installation, with the difference growing with increasing penetration. In addition, an obvious difference was found in the caisson tip resistance between these two installation methods.Key words: suction caisson, clay, large deformation finite element, soil plug, total stress changes, penetration resistance, factor of safety.
SEMI-AUTOMATIC DISTRIBUTED SYNTHESIS
Authors: SCHEWE SVEN , FINKBEINER BERND
Published: February 2007

We propose a sound and complete compositional proof rule for distributed synthesis. Applying our proof rule only requires the manual strengthening of the specification into a conjunction of formulas that can be guaranteed by individual black-box processes. All premises of the proof rule can be checked automatically.

For this purpose, we give an automata-theoretic synthesis algorithm for single processes in distributed architectures. The behavior of the local environment of a process is unknown in the process of synthesis and cannot be assumed to be maximal. We therefore consider reactive environments that have the power to disable some of their own actions, and provide methods for synthesis (and realizability checking) in this setting. We establish upper bounds for CTL (2EXPTIME) and CTL* (3EXPTIME) synthesis with incomplete information, matching the known lower bounds for these problems, and provide matching upper and lower bounds for μ-calculus synthesis (2EXPTIME) with complete or incomplete information. Synthesis in reactive environments is harder than synthesis in maximal environments, where CTL, CTL* and μ-calculus synthesis are EXPTIME, 2EXPTIME and EXPTIME complete, respectively.
POLAR ORDERING IN THERMOTROPIC MESOGENS RESOLVED BY SCANNING NLO MICROSCOPY
Authors: MORALES-SAAVEDRA OMAR G. , ANTAL JÁKLI , GERD HEPPKE , HANS J. EICHLER
Published: February 2007

A nonlinear optical (NLO) microscope has been developed based on recording the second harmonic generation (SHG) signals of the B 2- and B 4-phases of bent-shaped liquid crystalline (LC) materials. We observed that the microstructures of the polar order can be accurately characterized by 2D scanned images implementing this device. Specifically, we have investigated two bent-core compounds, which have either B 4 or B 2 phases at room temperature and exhibit SHG activity. The NLO microscope was calibrated according to the Maker fringe method allowing the in situ evaluation of the relative SHG efficiency. The developed NLO-microscopy device may serve as an important tool to characterize liquid crystalline features at a microscopic scale for both, fundamental and applied research.
Current Challenges with Copper Interconnects
Authors: Besser Paul R.
Published: February 2007

In the integrated circuit industry, aluminum-based interconnects and oxide interlayer dielectrics have been replaced with copper interconnects in a dual inlaid architecture and with low-K dielectrics. Inlaid Cu lines offer higher conductivity, improved electromigration performance and a reduced cost of manufacturing. In this manuscript, the current challenges with integrating Cu in high-performance integrated circuits are detailed. As technologies scale, the many steps in the integrated process flow cannot be viewed as independent. The interactions between process steps (module interactions) that must be considered will be discussed. The development of a reliable and manufacturable technology requires a fundamental understanding of these interactions. A process-oriented finite element model (FEM) will be presented to capture the effect of individual process steps on the stress evolution during processing. Finally, the future trends for Cu interconnect will be suggested.
Advanced Electrochemical Processes for Sub-50 nm On-chip Metallization
Authors: Akolkar Rohan , Cheng Chin-Chang , Chebiam Ramanan , Fajardo Arnel , Dubin Valery
Published: February 2007

Additives-assisted electrodeposition on a PVD copper seed is capable of generating void-free 'bottom-up' fill in vias and trenches with moderate aspect ratios (~10:1). For future generation copper interconnects, scaling causes the via and trench aspect ratios to increase, i.e., dual damascene aspect ratios larger than 10:1 due to the overhang caused by the PVD copper seed. For filling such aggressive geometries, advanced electroplating additives which provide improved suppression/acceleration properties need to be developed. In the present work, several gap-fill strategies for sub-50nm technology node will be outlined including: (i) Development and characterization of advanced electroplating additives, and (ii) Direct plating of copper on novel liner metals (e.g., Ru). Scaling of copper interconnects also necessitates improved electromigration resistance. Electroless Co caps will be discussed as a potential solution for improving reliability of sub-50nm copper interconnects.
Understanding the Initiation and Growth Variations of Electroless Cobalt Capping Layers at Different Features on Damascene Copper Interconnects
Authors: Chen Qingyun , Valverde Charles , Petrov Nicolai , Stritch Daniel , Hurtubise Richard , Witt Christian
Published: February 2007

Thickness discrepancies of electroless cobalt alloy deposition on different copper interconnect features, due to initiation and growth behavior variations, were observed. This paper describes the impact of bath formulations, additives and process conditions on initiation and growth behavior of electroless cobalt thin films on features with different metal densities. Root causes for initiation and growth variations are discussed.
Electroless Cobalt Deposition from Ammonia Borane Solutions.
Authors: Rohan James F. , Nagle Lorraine C. , Loughlin Alan
Published: February 2007

Ammonia borane (AB) has been used as a reducing agent in the deposition of cobalt on copper substrates. The bath composition for selective deposition was investigated. The mobile ion free plating bath was pH balanced and buffered using tetramethyl ammonium hydroxide. The codeposition of W with Co was achieved utilising tungstic acid. The electrochemical analysis of cobalt deposition and AB oxidation at the operating pH of 9 indicate that the deposition on copper is faster than that on cobalt and that the reaction rate decreases as the deposition proceeds.
Effect of Co(III) on Defectivity of Electroless Cobalt Capping Layers on Damascene Copper Interconnects
Authors: Chen Qingyun , Valverde Charles , Figura Paul , Paneccasio Vincent , Stritch Daniel , Hurtubise Richard , Witt Christian , Fang Hongbin , Weidman Timothy , Shanmugasundram Arulkumar
Published: February 2007

This work presents the impact of Co(III) species in electroless cobalt solutions on plating bath performance such as initiation and growth rate, deposit selectivity, coverage and uniformity. The results indicate that excessive Co(III) content can delay initiation significantly and cause copper erosion during induction period, leading to a decrease of deposit uniformity, an increased surface roughness, and in some cases loss of selectivity. Methods for inhibition of Co(III) formation are also presented.
Control of Overfill Bumps in Damascene Cu Electrodeposition
Authors: Moffat T. , Kim Soo-Kil , Josell Daniel
Published: February 2007

Electroanalytical measurements and feature filling experiments have been conducted to study the effect of levelers, such as dodecyltrimethylammonium chloride (DTAC) and branched polyethyleneimine (PEI), on Cu electrodeposition in the presence of various combinations of superfilling additives. Surface saturation of either leveler yields substantial inhibition of Cu deposition reaction that is similar in magnitude to that provided by PEG-Cl. Addition of the levelers to the PEG-Cl-SPS superfilling electrolyte leads to quenching of the characteristic voltammetric hysteresis. This behavior is attributed to ion-pairing between the cationic functional group of the leveler and the anionic sulfonate tail group of the accelerator SPS. This deactivation process stems from either leveler adsorption from the electrolyte and/or lateral interactions during area reduction in accordance with the curvature enhanced adsorbate coverage mechanism. The combined processes may be optimized to enable the bottom-up filling dynamic to be sustained while overfill bump formation is effectively attenuated.
Effect of Electrolyte Acidity on Copper Plating Process Performance
Authors: Witt Christian , Lin Xuan , Carpio Ron , Srinivasan J.
Published: February 2007

The effect of sulfuric acid concentration in copper electroplating has been evaluated for semiconductor interconnect fabrication. Gapfill rates and defect densities were determined for 10, 80, and 175 g/l sulfuric acid concentration. The results show an increase in bottom growth rate with increased acidity in addition to a shape change in the film growth front. Chonopotentiometry was used to study the effect of acidity on organic additive responses in these electrolytes. Opposed to low acid chemistry, the suppressor becomes mass transport limited at higher acidity, suggesting concentration gradients could be related to the gapfill differences observed. Defect densities for low acid chemistry were found somewhat higher than for high acid electrolyte. This could be caused by differences in wetting behavior between chemistries.
In Situ AFM Study of the Effect of Additives on the Morphology of Electrodeposited Copper
Authors: Buckley D. N. , Breathnach Mairead , Ahmed Shafaat , Nakahara Shohei
Published: February 2007

The effect of thiourea and polyethylene glycol (PEG) on the early stages of the electrodeposition of copper on a polycrystalline gold substrate in acidic CuSO4 was examined by in situ atomic force microscopy (AFM). Addition of 1 ppm thiourea resulted in much smaller more nodular features. Feature size decreased as the thiourea concentration was increased. At any given concentration of thiourea, the RMS roughness initially increased as the film thickness increased but eventually reached a saturated value. Copper electrodeposited in the presence of 300 ppm PEG showed much smaller feature sizes than in the absence of additives but not as small as those obtained in the presence of 20 ppm thiourea. The lateral size of surface features was also estimated. After 800 s of deposition at -100 mV (Cu/Cu2+), lateral feature sizes were 730 nm, 460 nm and 280 nm in the case of no additives, 300 ppm PEG and 20 ppm thiourea respectively.
Vacancy-Induced Plastic Deformation in Electrodeposited Copper Films
Authors: Buckley D. N. , Nakahara Shohei , Ahmed Shafaat , Ahmed Tanjim T.
Published: February 2007

A tensile stress developed in polycrystalline copper films during room-temperature aging was computed using a diffusion equation for excess vacancies migrating to the grain boundaries. This theory is based on an assumption that a free volume created by the arrival of excess vacancies at the grain boundaries of thin copper films is instantly eliminated and this action introduces a biaxial tensile stress over the film plane. The tensile stress was calculated as a function of aging time, grain size, and excess vacancy concentration. It was found that the tensile stress could exceed the yield stress of copper. This result suggests that a plastic deformation could occur in electrodeposited copper films during room- temperature aging, consistent with experimental observations.
Resistance Measurements and Simultaneous AFM Imaging on Electrodeposited Copper Films during Room Temperature Aging
Authors: Buckley D. N. , Ahmed Shafaat , Ahmed Tanjim T. , Gooberman G. , Nakahara Shohei
Published: February 2007

Electrical resistance measurements of 30 - 120 nm electrodeposited copper films were made simultaneously with atomic force microscopy (AFM) imaging. Resistance decreases relatively rapidly immediately after deposition. It reaches a minimum, typically after less than an hour, and then increases to a maximum and subsequently decays. AFM showed the formation of smaller surface features during the period of increase in resistance. Subsequent to the maximum in resistance, features increased in size, consistent with recrystallization and grain growth. It is speculated that the increase in resistance may to be related to structural changes in the film and that the early decrease in resistance may reflect a contribution from the out- diffusion of excess vacancies.
Simultaneous Filling of Microvia and Through Hole by Copper Electroplating for High Density Interconnection of PCB
Authors: Dow Wei-Ping , Chen Hsiang-Hao , Yen Ming-Yao , Liu Cheng-Wei
Published: February 2007

The development of high density interconnects (HDI) of IC packaging substrate and printed circuit board (PCB) will be a key technology for fabrication of consumer electronic products in next generation. To meet the demands and requirements of state-of-the-art microelectronic products, not only the microvias but also the through holes (THs) of IC substrate and PCB, which both are responsible for the interconnection, are needed to be metallized in a mode of full fill with copper. However, current copper electroplating technology using a direct current (DC) cannot carry out the through hole filling, but only the microvia filling. In this work, a novel copper electroplating formula is developed in order to achieve the through hole filling by employing a DC plating. In addition, this new plating formula can also simultaneously achieve the filling of microvia and through hole in one step, which effectively reduces the process steps of fabrication.
Underpotential Co-deposition of Cu1-xPtx Alloys
Authors: Mallett Jonathan J. , Svedberg Erik , Moffat T. , Egelhoff William , Bertocci Ugo , Bovevich John , Shapiro Alexander
Published: February 2007

The electrodeposition of Cu1-xPtx alloys by underpotential co- deposition of Cu with Pt is demonstrated using an H2SO4-CuSO4- PtCl42- electrolyte. The composition and structure of 1 micrometer thick alloy films grown at different potentials were examined by EDS, XRD and TEM. A thermodynamic rational for the alloying process is provided by a symmetrical regular solution model whereby underpotential co-deposition of Cu is ascribed to the negative enthalpy of mixing with Pt. The observed dependence of alloy composition on potential is in good agreement with equiatomic mixing enthalpy of -18 kJ/mol, obtained from calculations by Miedema et al. An EQCM was used to provide a time resolved assessment of the alloy formation process. Simultaneous measurement of the mass and current transients during potential steps enable the effects of submonolayer underpotential deposition of Cu onto a Pt rich surface to be observed and separated from the subsequent steady-state co-deposition of Cu with Pt.
Challenging the Electrodeposition of Thick Cadmium Telluride Layers
Authors: Rousset Jean , Lincot Daniel
Published: February 2007

The electrodeposition of thick films of CdTe (> 10 microns) has been studied under potential and current controlled conditions. The layers were characterized by SEM in order to investigate the morphological and compositional evolutions of the deposited material during the growth. Progressive enrichment in tellurium content and morphological transitions from dense to a columnar structure has been observed. These thickness-dependent properties have been compared to those observed with thin films(< 2 microns) as a function of the applied potential. Galvanostatic conditions were also tested and allowed to obtain thicker film up to 130 microns, but still with columnar structure.
Nucleation of Binary Cu-Se Phases and Electrochemical Cementation Mechanism on Polycrystalline Molybdenum Thin Films in Cu(II)-In(III)-Se(IV) Acidic Solutions
Authors: Chassaing Elisabeth , Ramdani Omar , Canava Bruno , Grand Pierre-Philippe , Lamirand Mélanie , Roussel Olivier , Etcheberry Arnaud , Guillemoles Jean-François , Lincot Daniel , Kerrec Olivier
Published: February 2007

The behavior of sputter deposited polycrystalline thin films of molybdenum covered glass plates, used as standard back contact for thin Cu(In, Ga)(S,Se)2 solar cells is examined while in contact with acidic aqueous solutions containing Cu(II), In(III) and Se(IV) species at open circuit potential. These solutions are used for the electrodeposition of CuInSe2 thin films. An electrochemical investigation was carried out, in combination with SEM-FEG observations, Raman spectroscopy and XPS surface analysis. It is shown that molybdenum undergoes an electrochemical cementation reaction. Its potential increases with immersion time. Immediately after immersion, small nuclei appear on the surface, which then grow to form a quasi-continuous layer after 600s. The chemical composition of the layer evolves with immersion time. No indium is incorporated. Cu-Se phases are formed whose composition changes from Se/Cu > 0.3 to a Se/Cu atomic ratio ~ 0.7. The final layer contains two phases, Umangite Cu3Se2 and CuSe.
Effect of Hydrogen Generation on Electrochemical Processing of Ni Nanowires and Nanotubes
Authors: Fukunaka Yasuhiro , Motoyama Munekazu , Sakka Tetsuo , Ogata Yukio
Published: February 2007

Cu and Ni were electrodeposited into polycarbonate track-etch membrane filters to fabricate the nanowire and nanotube arrays. First of all, the current efficiency (η) of Cu electrodeposition was measured at two potentials by analyzing the weight of samples by inductively-coupled plasma emission spectrometry. The measured η showed the well-convergent distribution with the standard deviation of 4% around the mean close to 100%. Then, the η of Ni electrodeposition was measured in the same way. It ranged from 25% to 100%. The smaller η favors the formation of Ni nanotubes, but, the tube wall thickness is not always in the order of the η.
Electrochemistry of Ta in Aqueous HF
Authors: Suni Ian
Published: February 2007

Understanding of aqueous Ta electrochemistry is important due to the development of electrochemical methods for Cu seed layer deposition and the development of low-stress electrochemical methods for Ta/TaN removal. Because Ta is a highly active metal, Ta electrochemistry in aqueous electrolytes has been largely unknown. We have studied the use of HF for dissolution of the native oxide, Ta2O5. Voltammetry and impedance studies of Ta discs, Ta/Si wafers, and TaN/Si wafers are reported here. Although the native oxide can be dissolved, Ta remains covered by an ultrathin film at most potentials in 2.5 M HF. Thus although Cu electrodeposition easily occurs from 2.5 M HF, adhesion is poor. Only galvanic displacement followed by electroless Cu deposition was successful in forming an adherent Cu film on a Ta rod electrode. On the other hand, despite the presence of this interfacial film, electrochemical dissolution of both Ta and TaN is easily demonstrated.
A Comparative Study of Ruthenium(0) MOCVD Precursor Complexes
Authors: Popovska Nadejda , Schneider Andreas , Jipa Ilona , Zenneck Ulrich
Published: February 2007

Ruthenium thin films were deposed by MOCVD at moderate tem- peratures using [(1,5-cyclooctadiene)(toluene)Ru(0)] (1) and [(benzene)(1,3-cyclohexadiene)Ru(0)] (2) as precursor. The incorporation of carbon in the films could not be completely avoided, because of the high catalytic activity of Ru for C-H as well as C-C activated reactions. However, using suitable ligand combination and opti-mized deposition conditions it was possible to minimize the amount of carbon in the Ru films. The complex (2) provides better films due to strong reduction of the gaseous follow-up products, no C-C activated reactions and minimum carbon incorporation at op-timized deposition temperature and gas velocity.
1.5 S-Butyl 1.5 N-Butyl Bismuth and 1.5-Butyl 1.5-Isopropyl Bismuth as new Liquid Bismuth Precursors for SBT Thin Film Deposition
Authors: Lisker Marco , Silinskas Mindaugas , Matichyn Serhiy , Lorenz V. , Edelmann F. T. , Burte Edmund
Published: February 2007

In this study, we have tested tributyl bismuth and, additionally, 1.5-butyl 1.5-isopropyl bismuth precursor in an atomic vapor deposition (AVD) system for SBT deposition. The Sr0.8-1Bi2-2.4Ta2O9 (SBT) thin films were deposited in a Tricent®-CVD reactor (AIXTRON AG) on Ir-coated 150 mm silicon (100) wafers. Strontium bis-pentaethoxymethoxyethoxy tantalate (Sr[Ta(OEt)5(OC2H4OMe)]2) was used as Sr-Ta source. Growth kinetics, structural and electrical properties of deposited films were investigated. The deposition rate for both bismuth precursors was almost the same and varied only depending on deposition temperature, pressure and injection parameters. The crystalline fluorite phase appeared at a higher deposition temperature (470-550 {degree sign}C). The SBT films annealed at 700 {degree sign}C were crystallized to the polycrystalline perovskite phase.
Iridium Electrodes for Ferroelectric Capacitors Deposited by Liquid-Delivery MOCVD and PVD
Authors: Lisker Marco , Ritterhaus Yves , Hur'yeva Tetyana , Burte Edmund
Published: February 2007

Thin iridium films are required as electrode material for ferroelectric capacitors. SBT (SrBi2Ta2O9) or PZT (Pb(ZrXTi1-X) O3) are often used as ferroelectric material in such capacitors. The PZT based non-volatile ferroelectric random access memories show better fatigue characteristics if platinum is replaced by iridium as electrode material. The iridium films were deposited on different substrates at room temperature by electron gun evaporation and at temperatures of 300 - 500 {degree sign}C by liquid-delivery MOCVD. The precursor Ir(EtCp) (1,5COD) [iridium(ethylcyclopentadienyl)(1,5-cyclooctadiene)] was diluted in toluene (0.1 M concentration) for the deposition experiments. The iridium films were deposited onto TiO2/SiO2/Si-, SiO2/Si-, and Si-substrates to compare the iridium film properties on different substrates. Annealing in an oxidizing ambient at temperatures above 700 {degree sign}C resulted in an increased oxidation of the CVD - films as proved by XRD analyses. Low resistivities of 7 - 70 µWcm were obtained for the as-deposited iridium films.
Investigation of Thermal Decomposition of the Titanium MOCVD Precursor [Ti(OPri)2(thd)2], Employing Matrix Isolation-FTIR Technique
Authors: Devi Anjana , Bhakta Raghunandan , Bettinger Holger
Published: February 2007

The use of matrix isolation (MI) technique coupled with FTIR as a tool for studying the gas-phase decomposition of the metal organic chemical vapor deposition (MOCVD) precursors is demonstrated. The thermoylses experiments on the well known titanium precursor complex [Ti(OPri)2(thd)2] (thd = tetramethylheptanedione) were carried out. The thermolysis was studied from ambient to 1000 {degree sign}C. FTIR bands due to products could be observed from 500 {degree sign}C up to 1000 {degree sign}C. Intermediates like the two conformers of pivaloylketene were observed for the first time during the thermolyses of [Ti(OPri)2(thd)2]. Based on the observations, the tentative mechanism involving the cleavage of metal to oxygen bond of the Hthd ligand and subsequent formation of pivaloylketene intermediates are proposed.
Gas Phase and Surface Chemical Kinetics in Silicon Chemical Vapor deposition
Authors: Koshi Mitsuo , Matsumoto Keiji
Published: February 2007

Some of the elementary reactions involved in CVD processes of SiH4 were investigated. Rae constant of SiH4 unimolecular decomposition was evaluated on the basis of the master equation analysis. It is confirmed that the SiH4 decomposition in most CVD condition is in the low-pressure limit. Rate constants for the multi-channel chemical activation reaction of SiH2+SiH4 were calculated by a novel dual transition state theory. It is suggested that the products channel to yield HSiSiH3+H2 can be important at the condition relevant to CVD processes. Surface reactions of H2SiSiH2 and SiH2Si were examined by means of quantum mechanical calculations of potential energy curves. H2SiSiH2 does not react with the Si surface terminated with hydrogen, whereas SiH2Si can react even with the terminated surface of Si with the activation energy of 11 kcal/mol.
High Efficient Capacitance Coupled Plasma Reactor for Enhanced Surface Reaction
Authors: Chiu Kin-Chung R.
Published: February 2007

Capacitance-coupled plasma reactors are widely used in the semiconductor industry for the plasma enhanced processes. The specific optimization of the electrode design and reactor construction is most critical to optimize the plasma process in general. This article explores the recent breakthroughs and advancements of the-state-of-the-art plasma technology of recent DryScrub patents and studies. I propose a new interpretation of the Paschen Curves with applications to current industrial practices.
Metal Oxide Coatings as Working Electrodes in Electrochromic Smart Windows
Authors: Gesheva Kostadinka A. , Ivanova Tatyana , Hamelmann Frank , Marsen Bjorn , Cole Brian , Miller Eric
Published: February 2007

The paper deals with investigation of the structure and optoelectronic properties of tungsten oxide films showing a high electrochromic performance. The thin films are deposited by three different deposition methods: APCVD technique, using pyrolytical decomposition at 200oC of W(CO)6 in Ar/O2 atmosphere, the reactive sputtering at low temperature and a simplified sol-gel process by spraying. The study is focused on a comparative study of their electrochromic properties in dependence on the deposition and annealing process parameters. All the films show electrochromic effect, with high colour efficiencies and optical modulation meeting the requirements of practical applications.
MOCVD of Strontium Tantalate Thin Films using Sr[Ta(OEt)5(OC2H4OMe)]2 as Precursor
Authors: Lisker Marco , Silinskas Mindaugas , Veit Peter , Burte Edmund
Published: February 2007

The strontium tantalate (STaO) films were deposited on silicon substrates by liquid delivery (LD) metalorganic chemical vapor deposition (MOCVD) using Sr[Ta(OEt)5(OC2H4OMe)]2 as a single strontium-tantalum precursor. The deposition of the films was investigated in dependence on process conditions, such as substrate temperature, pressure, and concentration of the precursor. The growth rate varied from 4 to 300 nm/h and the highest rates were observed at the higher values of process temperature, pressure, and concentration of the precursor. As- deposited STaO films were completely amorphous. Crystallization occurs only after annealing at higher temperatures (~1000{degree sign}C). Additionally, annealing reduced the interface state density and the leakage current but a SiO2 interlayer grew too.