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OBJECTIVES Most strokes associated with atrial fibrillation (AF) result from left atrial appendage thrombi. Oral anticoagulation can reduce stroke risk but is limited by complication risk and non-compliance. Left atrial appendage exclusion (LAAE) is a new surgical option to reduce stroke risk in AF. The study objective was to evaluate the safety and feasibility of standalone thoracoscopic LAAE in high stroke risk AF patients. METHODS This was a retrospective, multicentre study of high stroke risk AF patients who had oral anticoagulation contraindications and were not candidates for ablation nor other cardiac surgery. Standalone thoracoscopic LAAE was performed using 3 unilateral ports access and epicardial clip. Periprocedural adverse events, long-term observational clinical outcomes and stroke rate were evaluated. RESULTS Procedural success was 99.4% (174/175 patients). Pleural effusion occurred in 4 (2.3%) patients; other periprocedural complications were CONCLUSIONS Study proved that a new surgical option, standalone thoracoscopic LAAE, is feasible and safe. With this method, long-term stroke rate may be reduced compared to predicted for high-risk AF population.

Cancer is a significant public health problem worldwide. While there has been a steady decrease in the cancer death rate over the last two decades, the number of survivors has increased and, thus, cancer-related sequela. Pain affects the life of patients with cancer and survivors. Prescription opioids continue as the analgesic of choice to treat moderate-to-severe cancer-related pain. There has been controversy on whether opioids impact cancer progression by acting on cancer cells or the tumor microenvironment. The μ-opioid receptor is the site of action of prescription opioids. This receptor can participate in an important mechanism of cancer spread, such as perineural invasion. In this review, current evidence on the role of the μ-opioid receptor in cancer growth is summarized and preliminary evidence about its effect on the cross-talk between sensory neurons and malignant cells is provided.

The thickness of the pellicle is only a few tens of microns in extreme ultraviolet lithography (EUVL). This is because the absorption loss by the pellicle is high. Thus, the thickness and contamination on the surface of the EUVL pellicle are important factors for controlling the transmission of EUV light. In this work, we fabricate ultra-thin silicon-nitride membranes for EUVL pellicles and use micro-spot spectroscopic ellipsometry and imaging ellipsometry for characterization. We successfully deduce not only the thickness but also the optical function of the membrane. However, we found that some precautions were required for accurate measurement of the free-standing thin membranes by using ellipsometry. Issues related to the vibration of the membrane and the sensitivity of the measurement are discussed.

Patients with atrial fibrillation (AF) have an increased stroke risk. This can be managed by oral anticoagulation (OAC) but a substantial number of patients are ineligible. The left atrial appendage (LAA) is the predominant thrombus source in AF, thus LAA management may reduce stroke risk. We

Null imaging ellipsometry was developed to show the net change in polarization state between two samples. This system has no moving parts for nulling and does not exhibit azimuthal dependence on the optical elements. Therefore, this system is fast in data acquisition and easy to operate. In addition, image uniformity can be improved through a normalization process. For a demonstration, this system was applied to annealing studies of indium oxide thin films. The results show that this system can visualize the temperature dependence of the annealing as well as the progress of the annealing over time.Null imaging ellipsometry was developed to show the net change in polarization state between two samples. This system has no moving parts for nulling and does not exhibit azimuthal dependence on the optical elements. Therefore, this system is fast in data acquisition and easy to operate. In addition, image uniformity can be improved through a normalization process. For a demonstration, this system was applied to annealing studies of indium oxide thin films. The results show that this system can visualize the temperature dependence of the annealing as well as the progress of the annealing over time.

A multichannel spectroscopic ellipsometer is developed for real-time studies of thin films in a vacuum in the UV range. This system is mounted on a vacuum chamber to study the crystallization process of zirconium-oxide (ZrO2) thin film. The optical spectra of ZrO2 thin film are collected during the elevation of temperature. From the trend in the spectrum, we find that a threshold temperature for crystallization exists. Moreover, the crystallization occurs gradually over a certain range of temperatures between the threshold temperature and a critical temperature for full crystallization. The evolution of the dielectric function shows the development of critical peaks around 6.2 eV and 7.3 eV along with a shift of the absorption edge. To the best of our knowledge, this is the first in-situ study performed by using real-time vacuum UV spectroscopic ellipsometry, and we describe the system in detail.

A micro-spot spectroscopic ellipsometer covering 1.5–4.8 eV is developed using two infinity-corrected reflective objectives. Only a small portion of the entrance pupil in the objective is used to obtain a ~50 μm × 70 μm spot on a sample. However, non-normal reflections inside the objectives cause experimental errors (up to 2.3° in Δ) when they are arranged symmetrically about a sample. In this paper, we show how to diagnose the polarization errors associated with the reflective objectives and how to deal with them.

Photoresist lithography has been applied to the fabrication of micro/nano devices, such as microfluidic structures, quantum dots, and photonic devices, in MEMS (micro-electro mechanical systems) and NEMS (nano-electro-mechanical systems). In particular, nano devices can be expected to present different physical phenomena due to their three-dimensional (3D) structure. The flexible 3D micro/nano fabrication technique and its process simulation have become among the major topics needed to understand nano-mechanical phenomena. For this purpose, the moving-mask technology and the lithography processes for the positive- and negative-tone photoresists were modeled. The validity of the simulation of the proposed 3D nano/microstructuring was successfully confirmed by comparing the experiment results and the simulated results. Hence, the developed model and the simulation can present and optimize photoresist characteristics and lithography process conditions due to the various 3D nano/microstructures. They could be help in the understanding of nanomaterial and mechanical phenomena.

Zirconium oxide (ZrO2) is one of the candidate materials for the high-k dielectrics used in Dynamic random access memory (DRAM) devices. ZrO2 films in device structures are extremely thin, and their physical properties are highly sensitive to the preparation conditions. Thus, it is very important to monitor the properties of ZrO2 films during device fabrication. We investigated the optical, electrical and structural properties of ultrathin ZrO2 films with different thicknesses by various techniques, including vacuum UV spectroscopic ellipsometry. Particularly, the effects of annealing were studied in detail. The optical and the structural properties of thin ( 4 nm) were crystallized, and the threshold temperature for crystallization depended on thickness. That is, thicker films crystallized at lower temperatures.

Because top-down approaches, such as the extreme ultraviolet technique and high-index fluidbased immersion ArF lithography, may cover one or two generations, lithography technology for scaling down feature size to sub-10-nm is becoming more complex. The directed self-assembly technology of block copolymers is one candidate for next-generation lithography. In this paper, a directed self-assembly lithography process for block copolymers is modeled and simulated on a molecular scale to solve the challenges associated with directed self-assembly technology. Sub-10nm patterns can be formed by using precise pattern placement of a conventional ‘top-down’ optical lithography with the well-defined nanostructure and self-healing properties of ‘bottom-up’ block copolymer self-assembly. Simulation results matched the experiment results.

For the feature size scaling down to tens of nanometers, the top-down approaches are getting more severe because the extremely ultra-violet (EUV) technique, the high-index fluid-based immersion ArF lithography, and the double patterning technology (DPT) under development may be cover one or two generations. An alternative technology to extend lithography patterning beyond current resolution limits is to combine the top-down lithography and bottom-up assembly. In this paper, an directed self-assembly lithography process of ''bottom-up'' block copolymer self-assembly, is modeled and simulated in molecular-scale. Impacts of block polymer components on pattern formation are analyzed and discussed.

Pattern reduction has generated much interest in developing effective methods of reducing the feature sizes of microelectronic and data-storage devices. For below-32-nm node technology, the bottom-up approach, namely, self-assembly, has obstacles such as the insufficient support of processes and mass production, and the top-down approaches, namely, photolithography, the extremely ultraviolet (EUV) technique, and high-index fluid-based immersion ArF lithography, are still under development. As one of the solutions for below-32 nm node technology, double patterning technology (DPT) has been researched. In this paper, we analytically report that the DPT pattern is 3/2 times denser than the double exposure technology (DET) pattern, and three times denser than the single-exposure pattern. An algorithm of the inverse lithography technology (ILT) based on not mathematical functions but pixels and the lithography model is described and simulated. An algorithm of the DPT mask design with ILT is described in terms of how to use this ILT method in an integrated computational lithography platform to handle the DPT. For its accuracy, its simulation results are compared with the simulation results obtained without ILT and with the conventional serif optical proximity correction (OPC). The ILT results are better than other results. Hence, the ILT based on pixels and the lithography model and its application algorithm of DPT can reduce the design complexity of mask design and the cost of production of DPT for below 32 nm half pitch pattern generation.

Producing a sub-32 nm line and space pattern is one of the most important issues in semiconductor manufacturing. In particular, it is important to produce line and space patterns in flash memory-type devices because the unit cell is mostly composed of line and space patterns. The double patterning method is regarded as the most promising technology for producing a sub-32 nm half-pitch node. However, the double patterning method is expensive for the production and a heavy data split is required. In order to achieve cheaper and easier patterning, we propose a resist reflow process (RRP) for producing 32 nm 1:1 line and space patterns. In many cases, it is easier to produce a 1:3 pitch line and space pattern than a 1:1 pitch line and space pattern in terms of the aerial image, and RRP can transform a 1:3 pitch aerial image to a 1:1 resist image. We used a home-made RRP simulation based on the Navier–Stokes equation including the surface tension effect. Solid-E of Synopsis is used for the optical simulation, and electron-beam lithography is used for the experiment to verify the concept.