bluuebunny/crossref_metadata_2025 huggingface dataset:
Renal silica calculi in an infant
Authors: NISHIZONO TOSHIYUKI , ETA SHIN‐ICHI , ENOKIDA HIDEKI , NISHIYAMA KENRYU , KAWAHARA MOTOSHI , NAKAGAWA MASAYUKI
Published: December 2004

Abstract  We report on a rare case of urinary silica calculi in a 10‐month‐old boy. The boy showed acute pyelonephritis with left hydronephrosis. Ultrasonography and computed tomography revealed a calculus at the left ureteropelvic junction and three additional calculi in the left renal pelvis. Because his acute pyelonephritis was refractory to conventional chemotherapy, the patient underwent successful left percutaneous nephrostomy followed by percutaneous nephrolithotripsy for the renal calculi. All stones disappeared and his postoperative course was uneventful. On infrared spectrophotometry, the wavelength pattern of the stones exhibited two peaks at 1100 and 1650 cm−1, consistent with the determination that the calculi consisted of a mixture of silicate (78%) and calcium oxalate (22%). We consider that the etiology of the calculi in this child can be ascribed to the silicate‐rich water used to dilute milk. In Japan, 46 adult patients with urinary silicate calculi have been reported in the literature; however, there is no report of the disease in an infant in Japan.
Case of leiomyosarcoma of the renal pelvis
Authors: MINAMI HIDERO , UEKI OSAMU , TANAKA TAKUJI , NISHIDA HIDEAKI , HASHIMOTO TETSUO , KAWAGUCHI KOUHEI
Published: December 2004

Abstract  A 54‐year‐old man presented at the Mibayashi clinic with bowel discomfort. Ultrasonography showed a left renal mass and the patient was referred to Noto General Hospital for urological evaluation. Results of the physical examination were unremarkable, but computed tomography and magnetic resonance imaging demonstrated a large tumor in the middle of the left kidney. The patient underwent left nephrectomy. On hemisection of the kidney, a firm tumor, measuring 8 × 7.5 cm, was seen occupying the renal pelvis. The histological diagnosis was leiomyosarcoma arising from the right renal pelvis. No treatment was provided after surgery and no recurrence was observed 6 months postoperatively.
Therapeutic effect of transurethral needle ablation in non‐bacterial prostatitis: Chronic pelvic pain syndrome type IIIa
Authors: CHIANG PO HUI , CHIANG CHIN PEI
Published: December 2004

Aim:  Non‐bacterial prostatitis is difficult to manage with conventional treatment. This study was undertaken to evaluate the therapeutic effect of transurethral needle ablation (TUNA) on men with chronic inflammatory non‐bacterial prostatitis.

Methods:  Thirty‐two patients with non‐bacterial prostatitis (type IIIa) were treated with TUNA. The TUNA procedure, which uses radiofrequency energy, heats the prostate tissue to approximately 90–110°C over a 5‐min period. Evaluation consisted of a prostatitis symptom severity score chart, the monitoring of the leukocyte count in the expressed prostatic secretion (EPS) and a subjective global assessment.

Results:  The decrease in the prostate symptom severity score chart at 3 and 6 months compared with the baseline assessment was statistically significant. Analysis of the leukocyte levels in the EPS in 14 patients was available. All 14 patients had a decrease in the EPS leukocyte count 3 months after treatment. However, six of these men (43%) still had EPS leukocyte levels above the normal indices (>10 white blood cells per high‐power field). A second session of TUNA on these partial responders resulted in three of the six men obtaining a normal EPS leukocyte count. At 6 months following treatment, complete, partial and poor improvement in terms of subjective global assessment were noted in 60, 35 and 5% of patients, respectively. No major complications, including those of sexual dysfunction or retrograde ejaculation, were noted in this cohort.

Conclusions:  Transurethral needle ablation appears to be an easy, safe and effective treatment for men with chronic inflammatory non‐bacterial prostatitis.
Low‐grade renal epithelial tumor originating from the distal nephron
Authors: HARA NOBORU , KAWAGUCHI MAKOTO , KOIKE HIROSHI , TSUTSUI TOSHIKI , TAKAGI RYUJI , TAKAHASHI KOTA
Published: December 2004

Abstract  There are few published reports of low‐grade renal epithelial tumor originating from the distal nephron. However, it should not be disregarded clinically, because the actual number of patients with such tumors may be higher than expected. We investigated the immunohistochemical profile of a histologically distinct subtype of such a tumor in detail, in addition to the clinical course and imaging studies. The present study demonstrated that both glandular and spindle cell components of this tumor have a persistent characteristic of an epithelial tumor arising from the distal tubule or collecting duct. This tumor is a benign complex neoplasm that can be treated successfully with radical surgery. Beta‐catenin and E‐cadherin are suggested to play a crucial role in tumorigenesis and the biphasic arrangement of this neoplasm, concerning the expression of epithelial membrane antigen and carbohydrate antigen 19‐9. We suggest that the term ‘distal nephron epithelioma’ is appropriate for classifying such rare but clinicopathologically distinct tumors.
Rate of nosocomial transmission of vancomycin‐resistant enterococci from isolated patients
Authors: Cheng A. C. , Harrington G. , Russo P. , Liolios L. , Spelman D.
Published: December 2004

To evaluate an isolation policy for patients colonised with vancomycin‐resistant enterococci (VRE), we instituted active surveillance for transmission to uncolonised patients. Surveillance rectal swabs were taken and pulsed‐field gel electrophoresis was performed on positive isolates. VRE transmission with an identical genotype occurred in 5 patients, giving a transmission rate of 3.7 per 1000 patient days, or 1 patient per ward each week. The present study provides a baseline for ­assessment of VRE transmission and will be useful in evalu­ation of the effectiveness of infection control interventions. (Intern Med J 2004; 34: 510−512)
Elementary Propositions and Essentially Incomplete Knowledge: A Framework for the Interpretation of Quantum Mechanics
Authors: Demopoulos William
Published: December 2004

A central problem in the interpretation of non‐relativistic quantum mechanics is to relate the conceptual structure of the theory to the classical idea of the state of a physical system. This paper approaches the problem by presenting an analysis of the notion of an elementary physical proposition. The notion is shown to be realized in standard formulations of the theory and to illuminate the significance of proofs of the impossibility of hidden variable extensions. In the interpretation of quantum mechanics that emerges from this analysis, the philosophically distinctive features of the theory derive from the fact that it seeks to represent a reality of which complete knowledge is essentially unattainable.
The obesity syndrome and acanthosis nigricans. Acanthosis nigricans is a common cosmetic problem providing epidemiological clues to the obesity syndrome, the insulin‐resistance syndrome, the thrifty metabolism, dyslipidaemia, hypertension and diabetes mellitus type II
Authors: Maitra S K , Rowland Payne C M E
Published: December 2004

Obesity and its consequences are arguably the chief public health problems facing the developed world. Obesity causes many fatal diseases, in particular cerebrovascular and cardiovascular disease.

Acanthosis nigricans (AN) is a common cosmetic disability in pigmented ethnic groups. It may present with periorbital darkening or darkening of the neck or knuckles as well as acrochordons (skin tags) around eyelids, neck or axillae. The more classical AN of axillae and groins is less often a cosmetic disability, although it is an important physical sign. AN is very common in pigmented populations throughout the world, irrespective of domicile. It is rare in whites. AN is closely associated with all the features of the insulin‐resistance syndrome (IRS), especially obesity. AN and IRS share a similar prevalence and epidemiology.

IRS (also known as syndrome X or the deadly quartet) is characterized by insulin resistance (IR) and its associated conditions, including obesity, dyslipidaemia, hypertension and diabetes mellitus (DM) type II. The sequelae of IRS are cardiovascular and cerebrovascular disease. The origins of insulin resistance and its sequel, IRS, are debated. Insulin resistance can result from obesity. Also obesity usually presents before AN, hypertension or DM II. For these reasons it may be more helpful to recognize instead an obesity syndrome.

The obesity syndrome is characterized by a genetically determined thrifty metabolism that protects subjects in famine conditions but which, in conditions of plenty, leads to weight gain with all its consequences, including hyperlipidaemia, hypertension, IR with DM II, and, in due course, cerebrovascular and cardiovascular disease. In pigmented races, AN is an important early manifestation of the obesity syndrome.

AN helps identify persons at particular risk of developing the obesity syndrome, dyslipidaemia, hypertension and IR with DM II. Recognition of AN, therefore, offers important opportunities for health screening and preventative medicine.
The concept of safer face‐lifting
Authors: Frame J D , Frame J E
Published: December 2004

Face‐lifting is now a common aesthetic procedure, performed mainly by plastic surgeons but increasingly also by ENT surgeons, oral surgeons, general surgeons and dermatologists. The level of expertise is dependent on training and exposure to patients, in addition to basic surgical skills. With cosmetic surgery clients, a holistic approach to patients is becoming increasingly important and, with increasing demands from the Care Standards Committee, there should be less demand for part‐time aesthetic surgeons.

This paper describes the working practice and thought processes of a single surgeon, based on 14 years of a busy aesthetic surgery practice. There are numerous types of face‐lift described in the literature but, in practical terms, the simplest technique often gives the best result, with little risk of morbidity.

Undoubtedly, some clients need an aggressive approach but, in most cases, the vertical pull mini‐face‐lift gives consistently good results in cases that are carefully assessed preoperatively and managed by skilled aesthetic/plastic nurses in the postoperative period.

This paper is unique in its holistic approach to assessment, technique and aftercare. It is designed for the sensible surgeon, looking for a low‐risk technique that reaps professional satisfaction and a happy client base. The more complex face‐lift should be referred to recognized specialists in the field.
Temperature-dependent dc characteristics of an InGaAs∕InGaAsP heterojunction bipolar transistor with an InGaAsP spacer and a composite-collector structure
Authors: Chen Jing-Yuh , Chen Chun-Yuan , Lee Kuan-Ming , Yen Chih-Hung , Tsai Sheng-Fu , Cheng Shiou-Ying , Liu Wen-Chau
Published: December 2004

The temperature-dependent dc characteristics of an interesting heterojunction bipolar transistor with an InGaAsP spacer and an InGaAs∕InGaAsP composite-collector structure are studied and demonstrated. By employing the intermediate band-gap In0.72Ga0.28As0.61P0.39 material at the emitter-base and base-collector heterojunction, the electron blocking effect is effectively eliminated. The studied device gives the promising dc performances including the small offset and saturation voltages without degrading the breakdown behaviors. The typical incremental current gain of 114 and the maximum dc current gain of 118 are obtained. It is worthwhile to note that the desired current amplification over 11 decades of the magnitude of collector current IC is obtained in the studied device. Moreover, the switching or hysteresis phenomenon usually observed in InP-based devices is not seen in the studied device.
Development of projection optics set-3 for high-numerical-aperture extreme ultraviolet exposure tool (HiNA)
Authors: Oshino Tetsuya , Takahashi Shinichi , Yamamoto Takahiro , Miyoshi Tatsuya , Shiraishi Masayuki , Komiya Takaharu , Kandaka Noriaki , Kondo Hiroyuki , Mashima Kiyoto , Nomura Kazushi , Murakami Katsuhiko , Okuyama Takeshi , Oizumi Hiroaki , Nishiyama Iwao , Okazaki Shinji
Published: December 2004

We have developed a high-numerical-aperture extreme ultraviolet exposure tool (HiNA). HiNA is equipped with an illumination system, projection optics, a mask stage, and a wafer stage in the vacuum chamber. The projection optics consist of two aspherical mirrors (M1 and M2). The numerical aperture of the optics is 0.3. Thus far, we fabricated two sets of projection optics (set-1 and set-2). The wave-front errors of set-1 and set-2 were 7.5 and 1.9nm rms, respectively. We developed a third set of projection optics (set-3), the target wave-front error of which was less than 1nm rms. In set-3, we also attempted to reduce flare. We completed the mirror polishing, coating, and mirror adjustment of set-3. By using a recently developed polishing method, we reduced low-spatial-frequency roughness (LSFR), mid-spatial-frequency roughness (MSFR), and high-spatial-frequency roughness, simultaneously. The predicted wave-front error calculated from the LSFR number was 0.69nm rms. MSFR, which strongly affects the flare of the optics, was significantly reduced to less than 0.2nm rms. The estimated flare was 7%, which is significantly reduced to one-forth that of set-2. The wave-front error of set-3 was measured with the visible-light point diffraction interferometer after coating and assembly. The wave-front error measured after adjustment was 0.85nm rms, which is less than one-half the wave-front error of set-2. Set-3 will be completed after the cramping of the adjustment system, which is performed to prevent mirror displacement during transportation.
Dielectric function of thin-film titanium oxide with a granular nanostructure
Authors: Sorbello R. S. , DeLoach J. D. , Aita C. R. , Fejes P.
Published: December 2004

It is shown here that a simple weighted average dielectric function describes the experimental infrared reflection∕absorption spectra of titanium oxide films with a granular nanostructure. The films were grown on unheated substrates by reactive sputter deposition using a Ti metal target and a 10 mTorr pure O2 discharge. The films’ average dielectric function is derivable from a Maxwell-Garnett model in which randomly oriented nanograins with anatase short-range atomic order are embedded in a conducting background. In contrast, dielectric functions calculated using effective-medium and Maxwell–Garnett theories that do not consider the background fail to adequately account for the experimental absorption peak positions. High-resolution transmission electron microscopy confirmed the films’ granular nanostructure and the presence of Ti suboxides as a minority constituent. We associate the anatase-like constituent with the model’s embedded grains, and the Ti suboxide constituent with the model’s background medium. The formalism that is developed here is applicable to any composite system consisting of grains embedded in a medium whose dielectric function is much larger than that of the grains.
Formation of density controlled Cr-filled carbon nanotubes on Au–Cr solid solution
Authors: Kamide K. , Araki H. , Hiwatashi S. , Yoshino K. , Sakata T. , Lee J-Goo , Mori H.
Published: December 2004

Whisker-like carbon nanotubes with a controlled density (∼8.5×107tubes∕cm2) can be prepared on Au–Cr solid solution films with Cr concentration of 22.5–30.0atomic%, by thermal chemical vapor deposition using Ni-phthalocyanine as precursor. An inner hollow of the nanotube is filled with a single crystalline nanowire composed of Cr atoms. Crystal structure of those nanowires mostly agrees with that of the fcc type Au–Cr solid solution, and rarely takes a metastable structure such as A15 type of Cr as well as oxide (Cr3O4) or carbide (Cr3C2). It is suggested that Ni catalysis does not contribute in the form of nanoparticles to the growth processes of those nanotubes, but in the form of ultra-thin Ni film having many nanoholes. Those films play an important role to dissolve both Cr atoms and C atoms, and offer a stage for active surface diffusion of those atoms precipitated on those films.
Dielectric properties of highly (100) oriented (Pb0.5,Sr0.5)TiO3 thin films grown on Si with MgO buffer layer
Authors: Kim Kyoung-Tae , Kim Chang-II
Published: December 2004

Pb 0.5 , Sr 0.5 Ti O 3 (PST) thin films were deposited on Si with MgO (100) buffer layer by the alkoxide-based sol-gel method. Structural and dielectric properties of PST thin films for the tunable microwave device applications were investigated. For the MgO∕Si buffer layer, the PST thin films exhibited highly (100) orientation. The MgO buffer layer affects the stress state of the (100)-oriented PST thin films. The dielectric constant, tunability, and figure of merit of the highly (100)-oriented PST thin film increased with increasing annealing temperature due to the decrease in lattice distortion. The differences in dielectric properties may be attributed to the change in the film stress. The dielectric constants, dielectric loss and tunability of the PST thin films deposited on the MgO∕Si substrates measured at 10kHz were 822, 0.025, and 80.1%, respectively.
Effect of mask pattern correction for off-axis incident light in extreme ultraviolet lithography
Authors: Sugawara Minoru , Nishiyama Iwao , Takai Mikio
Published: December 2004

The effect of mask pattern correction for off-axis incident light on the pattern fidelity of a model pattern with 22nm wide lines and spaces was investigated. Corrections were made to the edges of mask patterns, because off-axis incident light produces an asymmetric aerial image. The corrections were found to compensate effectively for the degradation in pattern fidelity due to the influence of off-axis incident light and optical proximity effects. Off-axis incident light causes asymmetry in the positions of pattern edges, the mask error enhancement factor, and pattern edge contrast, even when a symmetric mask pattern layout is designed. It was found that these asymmetries could be suppressed by employing thin buffer and absorber films and a large numerical aperature of projection optics.
High resolution electron beam lithography using a chemically amplified calix[4]arene based resist
Authors: Sailer H. , Ruderisch A. , Henschel W. , Schurig V. , Kern D. P.
Published: December 2004

The calix[4]arene based resist tetrakis(oxiran-2-ylmethoxy)-tetra-tert-butylcalix[4]arene is presented. The well known chemical amplification techniques can be applied to the nonpolymeric class of calixarenes resulting in area doses below 100μC∕cm2 at 30keV beam energy. This is achieved by application of the concept of cationic polymerization to a calix[4]arene derivative bearing four epoxide residues together with a photoacid generating triarylsulfonium salt. The high resolution capabilities of this calixarene based resist remain mainly intact under optimized bake parameters.
Minimal zone plates for x-ray lithography
Authors: Amy D. , Jiang L. , Zheng R. , Feldman M. , Cerrina F. , Dhuey S. , Leonard Q. , Thielman D.
Published: December 2004

As feature widths in integrated circuits continue to decrease, patterning the smallest features has become more and more challenging. This is especially true for contact levels, where vias less than 50nm diameter will be extremely difficult to print. However, since vias are typically well separated, they are readily patterned by using zone plates to focus x rays. Although zone plates have been used to focus x rays to small spots for many years, it has generally been considered necessary to have more than about 10 zones to produce clean images, i.e., with minimal energy in the side lobes. However, we have found that zone plates useful for x-ray lithography may have small numerical apertures and as few as two zones, and still produce very small and clean images.
Mechanisms of nano-hole drilling due to nano-probe intense electron beam irradiation on a stainless steel
Authors: Bysakh S. , Shimojo M. , Mitsuishi K. , Furuya K.
Published: December 2004

Holes with diameters of a few nanometers were drilled in a stainless steel foil using intense electron beams of 2.4nm nominal probe size from a field-emission electron gun in a high-resolution transmission electron microscope. Drilling experiments were carried out at regions of different foil thicknesses for different durations using three different condenser lens apertures. A better understanding of the mechanisms of nano-hole drilling by nano-probe electron beams has been achieved in this article. It was observed that the drilling process initiates from the bottom surface of a thin region while it initiates from the top surface for a thick region. It is concluded that material removal during nano-hole drilling is mainly by localized vaporization within the foil and drilling progresses through the formation of a row of interconnected nano-voids along the irradiated volume across the foil thickness.
Effects of postannealing on the bulk and interfacial characteristics of ZrO2 gate dielectrics prepared on Si by metalorganic chemical vapor deposition
Authors: Huang Shih-Sian , Wu Tai-Bor
Published: December 2004

This work investigates the effects of postannealing on the bulk and interfacial characteristics of ultrathin ZrO2 films on Si substrates. The films were prepared by metalorganic chemical-vapor deposition and were subsequently annealed in N2 or O2 ambient at 500–900°C. Partial crystallization of the ZrO2 film and growth of an interfacial layer (IL) were found by the increase of the annealing temperature. The IL is mainly composed of Zr–silicate for annealing in N2, but it is mostly SiO2 for annealing in O2. The annealing also effectively reduces the oxide trapped-charge density in ZrO2, as demonstrated by the reduction of hysteresis in the capacitance–voltage relation, but not for the specimen annealed in O2 at 900°C, in which excessive oxygen diffused into the film and IL was found. Lower leakage current from substrate injection in association with the reduction of depletion layer, which provides less generation current, was found due to the growth of Zr–silicate IL in N2 annealing, but the leakage from gate injection increased in conjunction with the crystallization of the ZrO2 layer. In contrast, the relatively thick SiO2 IL formed in O2 annealing reduces the leakage for both substrate and gate injection. There is also a significant shift of the turn-around voltage in the current–voltage relation with voltage swept from inversion to accumulation, but not with voltage swept back.
Nanocomposite low-k SiCOH films by plasma-enhanced chemical vapor deposition using vinyltrimethylsilane and CO2
Authors: Jeong Ki-Hun , Park Sung-Gyu , Rhee Shi-Woo
Published: December 2004

SiCOH films were deposited with plasma-enhanced chemical vapor deposition using vinyltrimethylsilane (VTMS) as a precursor and CO2 as an oxidant. The properties of the films were compared with those films deposited with VTMS and O2. As-deposited films and the films annealed at 360°C have been characterized. The growth rate decreased with increasing substrate temperature and increased with increasing CO2∕precursor ratio and plasma power. The dielectric constant was inversely proportional to the relative carbon content and the films deposited with CO2 had a higher carbon content than those deposited with O2. It was confirmed that CO2 was more effective to increase the carbon content. The refractive index of the as-deposited films was about 1.48–1.49 and decreased to 1.46 after annealing. The reduction of the refractive index was due to the lower density and increased porosity of the film. After annealing, the SiCOH films showed a low dielectric constant of 1.9 at optimum condition.
Formation of silicon on plasma synthesized aluminum nitride structure by ion cutting
Authors: Zhu Ming , Chen Peng , Fu Ricky K. Y. , Liu Weili , Lin Chenglu , Chu Paul K.
Published: December 2004

The application of silicon-on-insulator (SOI) substrates to high-power integrated circuits is hampered by self-heating effects due to the poor thermal conductivity of the buried SiO2 layer. We propose to replace the buried SiO2 layer in SOI with a plasma synthesized AlN thin film to mitigate the self-heating penalty. The AlN films synthesized on silicon by metal plasma immersion ion implantation and deposition exhibit outstanding surface topography and excellent insulating characteristics. Using a modified direct bonding process in conjunction with hydrogen-induced layer transfer, a silicon-on-AlN structure has been successfully fabricated. Cross-sectional high-resolution transmission electron microscopy, x-ray photoelectron spectroscopy, and spreading resistance profiling results reveal a uniform buried AlN layer beneath a single crystal Si overlayer. The interfaces between the top Si layer, buried AlN layer, and Si substrate are smooth and sharp. Moreover, the use of relatively thick buried AlN layer bodes well for SOI wafers in high voltage and high power applications.
Investigations of the Ga+ focused-ion-beam implantation in resist films for nanometer lithography applications
Authors: Arshak Khalil , Mihov Miroslav , Nakahara Shohei , Arshak Arous , McDonagh Declan
Published: December 2004

A focused-ion-beam (FIB) machine is a versatile tool used extensively in the IC industry for conducting failure analysis, prototype fabrication, and device repair. Lithography can also be performed by the FIB technique for direct patterning of photoresists, followed by wet or dry development. We studied how the property of resist regions changes during oxygen dry development in the NERIME (the negative-resist-image-by-dry-etching) process after subjecting to FIB-assisted gallium implantation. The NERIME process is a single-layer scheme, in which DNQ/Novolak-based resists are exposed by gallium ions with FIB, followed by near-ultraviolet flood exposure, silylation, and oxygen dry etching. This process can yield both positive and negative resist images. In addition, the NERIME technique can achieve a nanometer resolution down to 80nm and a high aspect ratio for the processed patterns. A scanning-transmission-electron-microscope (STEM) analysis of the resist regions FIB-implanted with gallium ions has revealed that there is a ∼15-nm-thick gallium oxide (Ga2O3) layer on the surface. The presence of the gallium oxide layer was found to provide an increased resistance against subsequent oxygen dry development. It was concluded that the NERIME process could be used for a specific CMOS processing task, such as high-resolution lithography over resist surfaces with complex topography.
Photonic crystals in polymers by direct electron-beam lithography presenting a photonic band gap
Authors: Panepucci Roberto R. , Kim Bryan H. , Almeida Vilson R. , Jones Matthew D.
Published: December 2004

Direct lithography in electron-beam sensitive polymers was investigated to fabricate 2D-slab polymer-based photonic crystal structures. Polymethyl-methacrylate (PMMA) doped with azo dye Disperse Red 1 (DR1) chromophores was used as a test material to produce optimized low-index contrast photonic crystals presenting a photonic band gap for TE polarization. Extensive computational simulations of the full 3D-slab modes guided the design and fabrication strategy through optimization of the lattice structure, lattice parameter, hole size, and slab thickness. An exposure strategy that takes advantage of 100kV beam energy for deep lithography, and exposure control for multilevel pattern definition is presented, resulting in the high aspect ratio and verticality required to achieve a strong band gap effect. Finally, a method that enables a high-quality air-clad PMMA-DR1 to be fabricated and integrated with optical waveguides for characterization is presented, enabling successful observation of a photonic bandgap in a 2D-slab polymer photonic crystal.
Impacts of probe-tip tilt on scanning probe microscopy
Authors: Mizuno Fumio , Misumi Ichiko , Gonda Satoshi , Kurosawa Tomizo
Published: December 2004

The effects of tip tilt on measurement uncertainty in scanning probe microscopy and tip-shape calibration for inclined tip have been discussed. Uncertainty of the untouchable region is the essential component of measurement uncertainty. Tip tilt is one of the most important parameters to determine the uncertainty of the untouchable region. The presence of tip tilt deteriorates fidelity of images and precision of critical-dimension measurements. It is necessary to use equivalent tip for calibrating the dilation of feature by inclined tip.
Sub-50nm half-pitch imaging with a low activation energy chemically amplified photoresist
Authors: Wallraff G. M. , Medeiros D. R. , Sanchez M. , Petrillo K. , Huang W.-S. , Rettner C. , Davis B. , Larson C. E. , Sundberg L. , Brock P. J. , Hinsberg W. D. , Houle F. A. , Hoffnagle J. A. , Goldfarb D. , Temple K. , Wind S. , Bucchignano J.
Published: December 2004

Critical lithographic dimensions are rapidly approaching the sub-50nm regime where there is a concern that image blur due to acid diffusion will impose a practical limit to the resolution of chemically amplified (CA) resists. Although recent EUV and 193- and 157nm immersion interferometric experiments have reportedly resolved line-space arrays with individual dimensions on the order of ∼40nm, smaller nested features are likely to prove problematic. Numerous reports suggest that conventional photoresist performance degrades rapidly at half-pitch dimensions in this range. New approaches to processing and materials development of photoresists will likely be required if the concept of chemical amplification is to be extended to the 32nm node and beyond. In this article we show that through materials choice and proper processing, image blur can be controlled to an extent where dense features below 40nm can routinely be resolved in CA resists. We describe our studies on high-sensitivity resists of differing activation energies and demonstrate the effect of postexposure bake conditions on the ultimate resolution. Most notably, electron-beam exposure of a CA resist that requires no postexpose bake has demonstrated half-pitch resolution down to 30nm with reasonable process latitude. Acid diffusion measurements performed on the same systems using a 193nm top surface-imaging-technique correlate with the observed resolution of the different resists and processing conditions. Additionally, this system has been probed to explore the effect of humidity on the rate of the resist deprotection reactions in order to determine the impact this might have on resolution.
Pt nanostructured electrode encapsulated by a tantalum oxide for thin-film fuel cell
Authors: Park Kyung-Won , Sung Yung-Eun
Published: December 2004

A nanostructured electrode, fabricated by means of a co-sputtering method, consisting of Pt nanophases of polycrystalline structure and amorphous tantalum oxide was characterized by transmission electron microscopy, x-ray diffraction, and x-ray photoelectron spectra analysis. The Pt nanostructured electrode showed excellent performance, that is, much higher current density of methanol electro-oxidation, compared to a typical Pt thin-film electrode. The origin of the enhanced performance in the nanostructured electrode appears to be due to an increased surface area of Pt catalyst in the porous oxide matrix, used as a support for the Pt nanophases and a pathway for transporting methanol as a fuel and protons.
Etching of porous SiOCH materials in fluorocarbon-based plasmas
Authors: Posseme N. , Chevolleau T. , Joubert O. , Vallier L. , Rochat N.
Published: December 2004

This work focuses on the etching of different porous methylsilsesquioxane materials (spin on SiOCH, k=2.2) with different porosity (30%, 40% and 50%) in fluorocarbon-based plasmas (CF4∕Ar). The etching of these materials is performed on blanket wafers in a magnetically enhanced reactive ion etcher. The surface and bulk modification after partial etching are studied using different surface analysis techniques such as quasi-in-situ x-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FTIR), and attenuated total reflection spectroscopy (FTIR-ATR). Similar to nonporous SiOCH materials, a decrease in etch rate of porous SiOCH films is observed with either increasing Ar dilution or polymerizing gas addition (CH2F2), which can lead in this last case to an etch stop phenomenon. The etch rate increases with higher porosity in the SiOCH film, since less material per unit thickness needs to be removed as the porosity increases. The XPS results show that a fluorocarbon layer is formed at the surface of the porous material and complementary angle resolved XPS analyses reveal that fluorocarbon species diffuse through the pores into the material. After partial etching, FTIR and ATR analyses reveal a carbon depletion in the remaining film, which indicates that the porous material is altered during plasma exposure. The film degradation is more important as the porosity increases. The etch rate evolution and film degradation are discussed and interpreted in terms of etching mechanisms and plasma surface interaction.
High resolution and aspect ratio two-dimensional photonic band-gap crystal
Authors: Teo Selin H. G. , Liu A. Q. , Singh J. , Yu M. B.
Published: December 2004

This paper reports the challenges resolved to realize high aspect ratio pillar-type two-dimensional photonic band-gap crystal (PhC), designed for application at the optical communication wavelengths. Specifically, the issue of a drastically reduced process window of deep UV lithography and deep reactive ion etching, for a super dense array of submicron size pillars with a diameter of 230nm and a spacing of 340nm is treated. A rigorous design of experiments yielded high-resolution PhCs with precise lattice dimensions even near regions of “defect structures” designed for device operations. At the same time, in the etching process, the stringent requirement of an etch angle needed for successful realization of such a super dense array of submicron size PhC lattice was also satisfied to yield sidewalls of high verticality, aspect ratios greater than 50, and scallop-depths of 12nm.
Temperature distributions to correct distortions in membrane masks
Authors: Jiang L. , Feldman M.
Published: December 2004

Adaptive membrane masks have recently been reported for the correction of distortions in integrated circuit masks and wafers. In these masks radiative heating is selectively applied to portions of the mask membranes. By controlling local heating, dimensional changes are made to the membrane which correct overlay errors between the mask and the wafer. The method is applicable to almost all of the next generation lithographies, and can correct distortions arising from the mask, the wafer, or the exposure tool. In previous work it was assumed that in-plane heat flow through the thin membranes was negligible, and that the local temperature rise was proportional to the heat input. The present work demonstrates that although there is substantial in-plane heat flow, its effects may be accounted for and a very wide range of temperature distributions may be generated on the membrane. These temperature distributions can then be used to correct almost arbitrary distortions.
Approach to full-chip simulation and correction of stencil mask distortion for proximity electron lithography
Authors: Sawamura J. , Suzuki K. , Omori S. , Ashida I. , Ohnuma H.
Published: December 2004

An approach for simulating the in-plane displacements of mask patterns induced by pattern-density gradients over thin membranes of a stencil mask as used for proximity electron lithography (PEL) has been proposed and demonstrated for the contact layer of a real device in the 65 nm node. The comparison of simulation and experiment shows that full-chip analysis is feasible if the method for tuning the boundary condition for the simulation to match with the experiment is established.
Cs
halide photocathode for multi-electron-beam pattern generator
Authors: Maldonado Juan R. , Coyle Steven T. , Shamoun Bassam , Yu Ming , Gesley Mark , Pianetta Piero
Published: December 2004

A unique approach to photocathode operation is described in this article. We utilize a relatively large bandgap CsBr photocathode material that under normal conditions would not photoemit with radiation energy less than the bandgap plus the work function. However, the material can be activated by proper UV illumination to obtain photoemission at wavelengths as long as 532nm. Photoyields as high as several hundred nA∕mW and current densities greater than 100A∕cm2 have been routinely obtained with lifetimes (50% degradation) well in excess of 200h at 257nm. The performance of the photocathode meeting all the requirements for a multi-electron-beam pattern generator will be presented.
Photonic crystal waveguides with propagation losses in the 1dB∕mm range
Authors: Zimmermann J. , Scherer H. , Kamp M. , Deubert S. , Reithmaier J. P. , Forchel A. , März R. , Anand S.
Published: December 2004

High-quality photonic crystal waveguides have been fabricated in the InGaAsP∕InP and GaAs∕AlGaAs material systems aimed at the communication wavelengths of 1.55 and 1.31 μm. The waveguides consist of omitted rows of holes in a triangular lattice of air holes etched into the semiconductor heterostructures by electron cyclotron resonance reactive ion etching. Efficient waveguiding has been observed in optical transmission measurements, with waveguide losses ranging from 1.5dB∕mm for a waveguide with three missing row of holes (W3) to 0.2dB∕mm for seven missing rows (W7).
Angular dependency of off-axis illumination on 100-nm-width pattern printability for extreme ultraviolet lithography: Ru/Mo/Si reflector system
Authors: Kang In-Yong , Chung Yong-Chae , Ahn Jinho , Oh Hye-Keun , Watanabe Takeo , Kinoshita Hiroo
Published: December 2004

The pattern printability of the Ru/Mo/Si system was quantitatively investigated by two successive schemes, reflectivity of the mask, and aerial image intensity transferred through the system. The reflectivity of a Ru/Mo/Si reflector was calculated and compared with the value of Mo/Si reflector for various incident angles (0°–5°) using Fresnel equation. In order to verify angular dependency of aerial image intensity in a Ru/Mo/Si reflector, we employed SOLID-EUV, which is capable of rigorous electromagnetic field computation. In the calculation, 100 nm line and space pattern was generated by 2D mask geometry with perfect absorber of opaque material. Through the investigation of the angular dependency on the pattern printability of Ru/Mo/Si and Mo/Si reflectors, we could suggest the optimal reflector system for specific condition of incident angle, i.e., Ru/Mo/Si system for ≲3° and Mo/Si system for ≳4° for maximizing optical performance of the EUVL system.
Writing strategy and electron-beam system with an arbitrarily shaped beam
Authors: Babin Sergey
Published: December 2004

The greatly increased complexity of modern masks has in turn led to increased write times and cost of the masks. Any opportunity to decrease write time while providing the required accuracy of the fabricated pattern is highly beneficial. A writing strategy using an arbitrarily shaped beam (ASB) results in a considerably smaller number of flashes to write a complex pattern compared to other strategies. The design of an ASB system is proposed. The ASB electron-beam column is similar to that of a variable-shaped beam system, except for a modified beam-shaping block. This suggests the relatively easy integration of an ASB column. The throughput of an ASB system is higher than the throughput of other systems, except for patterns with low coverage or simple geometries. In addition to the throughput advantages, an ASB system enables higher accuracy, including the feasibility of writing features according to “ideal” optical proximity correction.
Electron beam induced conductivity in polymethyl methacrylate, polyimide, and SiO2 thin films
Authors: Bai Min , Pease Fabian
Published: December 2004

Electron beam induced conductivity (EBIC) is one sensitive parameter that controls the charging of insulating materials under electron beam irradiation. In an earlier work [J. Vac. Sci. Technol. B 21, 2638 (2003)], we reported the measurement of EBIC in polymethyl methacrylate (PMMA) and thermal SiO2 thin films using an external bias method. The thin films under test were sandwiched between a silicon substrate and a metal electrode. One important observation is that the exposed region in the PMMA resist is ohmic regardless of the bias polarity. However, the EBIC in the metal-thermal oxide-silicon structure is highly asymmetric under opposite bias polarities. A model involving the internal emission of secondary electrons was proposed to interpret the asymmetric EBIC in thermal oxide. In this study, we extend the EBIC measurements to deposited SiO2 thin film and another polymeric material, polyimide. By putting the deposited oxide between symmetric metal electrodes, we validated the conjecture of the internal secondary electron emission from silicon substrate into thermal oxide when silicon is used as the bottom electrode. The results on deposited oxide also implicate the close dependence of EBIC in oxide on the property of Si∕SiO2 interface. On the other hand, under the same exposure condition, polyimide thin film is 50 times more conductive than PMMA, probably as a result of their different molecular structures.
ORI findings of scientific misconduct in clinical trials and publicly funded research, 1992–2002
Authors: Reynolds Sandra M
Published: December 2004

Background Since 1992 the Office of Research Integrity (ORI) had reviewed investigations of scientific misconduct in research funded by the US Public Health Service (PHS). ORI defined scientific misconduct as “fabrication, falsification, plagiarism, or other practices that seriously deviate from those that are commonly accepted within the scientific community for proposing, conducting, or reporting research”.

Purpose The purpose of this study was to summarize the findings and administrative actions reported in ORI notices of scientific misconduct in clinical trials occurring between May 1992 and 2002.

Methods Findings of misconduct were gathered from publicly available sources: the ORI annual reports and the NIH Guide to Grants and Contracts.

Results Clinical trials accounted for 17 (13%) of the 136 investigations that resulted in findings of scientific misconduct, and they were noted in 12 (11%) of the 113 brief reports of investigations closed with findings of no scientific misconduct. In clinical trials, the most severe sanction, debarment from US Government funding, was applied in six (35%) of the cases of misconduct compared to 79 (66%) of 119 cases from all other types of research combined. Of individuals cited for misconduct in clinical trials, three (18%) held doctorates in contrast to 81 (68%) in other types of research.

Conclusions In clinical trials, junior employees may bear the burden of sanction for scientific misconduct. The most frequently applied sanction was the requirement that a plan of supervision of the sanctioned employees accompany any future application for funding which would include them. This imposition of sanction on an individual employee does not address possible causes of misconduct which may be inherent in the overall pattern of leadership, training and supervision in the trial. Furthermore, the definition of misconduct, as interpreted by the Departmental Appeals Board, excludes carelessness and other poor research practices that may lead to dissemination of more incorrect data than misconduct.
The Vermont Diabetes Information System (VDIS): study design and subject recruitment for a cluster randomized trial of a decision support system in a regional sample of primary care practices
Authors: MacLean Charles D , Littenberg Benjamin , Gagnon Michael , Reardon Mimi , Turner Paul D , Jordan Cy
Published: December 2004

Background Despite evidence that optimal care for diabetes can result in reduced complications and improved economic outcomes, such care is often not achieved. The Vermont Diabetes Information System (VDIS) is a registry-based decision support and reminder system based on the Chronic Care Model and targeted to primary care physicians and their patients with diabetes.

Purpose To develop and evaluate a regional decision support system for patients with diabetes.

Methods Randomized trial of an information system with clustering at the practice level. Ten percent random subsample of patients selected for a home interview. Subject and setting includes 10 hospitals, 121 primary care providers, and 7348 patients in 55 Vermont and New York primary care practices.

Results We report on the study design and baseline characteristics of the population. Patients have a mean age of 63 years and a mean glycosolated hemoglobin A1C of 7.1%. Sixty percent of the population has excellent glycemic control (A1C, 7%); 45% have excellent lipid control (serum LDL-cholesterol,100 mg /dL and serum triglycerides,400 mg/dL). Twenty-five percent have excellent blood pressure control (,130/80 mm Hg). These results compare favorably to recent national reports. However, only 8% are in optimal control for all three of hyperglycemia, lipids and blood pressure.

Conclusions Our experience to date indicates that a low cost decision support and information system based on the Chronic Care Model is feasible in primary care practices that lack sophisticated electronic information systems. VDIS is well accepted by patients, providers and laboratory staff. If proven beneficial in a rigorous, randomized, controlled evaluation, the intervention could be widely disseminated to practices across America and the world with a substantial impact on the outcomes and costs of diabetes. It could also be adapted to other chronic conditions. We anticipate the results of the study will be available in 2006.
A Novel Approach to Synthesize Hollow Calcium Carbonate Particles
Authors: Han Yong Sheng , Hadiko Gunawan , Fuji Masayoshi , Takahashi Minoru
Published: December 2004

Hollow calcium carbonate particles were synthesized by a novel and facile approach which involves bubbling the CO2/N2 mixed gases into CaCl2 solution. The hollow particles were formed by the aggregation of nano-sized spherical particles on bubble surface. The formation mechanism was firstly proposed and the interaction of particles with bubbles was discussed.
Das Experiment: Ionenselektive Elektroden
Authors: Wenck Helmut , Höner Kerstin
Published: December 2004

Elektroden, die ein bestimmtes Ion in Gegenwart anderer Ionen selektiv anzeigen, werden als ionenselektive Elektroden bezeichnet. Herstellung und Wirkungsweise dieser Elektroden lassen sich in einem einfachen Experiment zeigen.
Die PCR – eine Revolution in der DNA‐Analytik
Authors: Krauss Gerhard
Published: December 2004

Kaum eine Methode hat die Analytik der Desoxyribonucleinsäure (DNA) so revolutioniert wie die Polymerase‐Kettenreaktion (Polymerase Chain Reaction, PCR), eine DNA‐Vervielfältigungstechnik. Sie wird auf so verschiedenen Gebieten wie der Gerichtsmedizin, Gentechnologie, der medizinischen Diagnostik sowie der Paläontologie eingesetzt. Doch damit sind ihre Möglichkeiten noch lange nicht ausgeschöpft.
Die molekulare Architektur des Exoskeletts von Insekten
Authors: Peter Martin G.
Published: December 2004

Bei den Insekten dient das Exoskelett nicht nur als Stützapparat für die Fortbewegungsmuskulatur, sondern auch als Barriere gegen schädliche Einwirkungen. Die Hauptkomponenten des Exoskeletts sind Chitin, Proteine und phenolische Verbindungen. Der vorliegende Aufsatz behandelt den Aufbau und einige Materialeigenschaften der Insektencuticula und geht dann ausführlicher auf die Mechanismen der Aushärtung (Sklerotisierung) des Exoskeletts ein.