Characterization of carbon contamination under ion and hot atom bombardment in a tin-plasma extreme ultraviolet light source

Molecular contamination of a grazing incidence collector for extreme ultraviolet (EUV) lithography was experimentally studied. A carbon film was found to have grown under irradiation from a pulsed tin plasma discharge. Our studies show that the film is chemically inert and has characteristics that are typical for a hydrogenated amorphous carbon film. It was experimentally observed that the film consists of carbon (~70 at. %), oxygen (~20 at. %) and hydrogen (bound to oxygen and carbon), along with a few at. % of tin. Most of the oxygen and hydrogen are most likely present as OH groups, chemically bound to carbon, indicating an important role for adsorbed water during the film formation process. It was observed that the film is predominantly sp3 hybridized carbon, as is typical for diamond-like carbon. The Raman spectra of the film, under 514 and 264 nm excitation, are typical for hydrogenated diamond-like carbon. Additionally, the lower etch rate and higher energy threshold in chemical ion sputtering in H2 plasma, compared to magnetron-sputtered carbon films, suggests that the film exhibits diamond-like carbon properties.Comment: 18 pages, 10 figure

Numerical and experimental studies of the carbon etching in EUV-induced plasma

We have used a combination of numerical modeling and experiments to study carbon etching in the presence of a hydrogen plasma. We model the evolution of a low density EUV-induced plasma during and after the EUV pulse to obtain the energy resolved ion fluxes from the plasma to the surface. By relating the computed ion fluxes to the experimentally observed etching rate at various pressures and ion energies, we show that at low pressure and energy, carbon etching is due to chemical sputtering, while at high pressure and energy a reactive ion etching process is likely to dominate

Plasma probe characteristics in low density hydrogen pulsed plasmas

Probe theories are only applicable in the regime where the probe's perturbation of the plasma can be neglected. However, it is not always possible to know, a priori, that a particular probe theory can be successfully applied, especially in low density plasmas. This is especially difficult in the case of transient, low density plasmas. Here, we applied probe diagnostics in combination with a 2D particle-in-cell model, to an experiment with a pulsed low density hydrogen plasma. The calculations took into account the full chamber geometry, including the plasma probe as an electrode in the chamber. It was found that the simulations reproduce the time evolution of the probe IV characteristics with good accuracy. The disagreement between the simulated and probe measured plasma density is attributed to the limited applicability of probe theory to measurements of low density pulsed plasmas. Indeed, in the case studied here, probe measurements would lead to a large overestimate of the plasma density. In contrast, the simulations of the plasma evolution and the probe characteristics do not suffer from such strict applicability limits. These studies show that probe theory cannot be justified through probe measurements

Estimating outflow facility parameters for the human eye using hypotensive pressure-time data

We have previously developed a new theory for pressure dependent outflow from the human eye, and tested the model using experimental data at intraocular pressures above normal eye pressures. In this paper, we use our model to analyze a hypotensive pressure-time dataset obtained following application of a Honan balloon. Here we show that the hypotensive pressure-time data can be successfully analyzed using our proposed pressure dependent outflow model. When the most uncertain initial data point is removed from the dataset, then parameter estimates are close to our previous parameter estimates, but clearly parameter estimates are very sensitive to assumptions. We further show that (i) for a measured intraocular pressure-time curve, the estimated model parameter for whole eye surface hydraulic conductivity is primarily a function of the ocular rigidity, and (ii) the estimated model parameter that controls the rate of decrease of outflow with increasing pressure is primarily a function of the convexity of the monotonic pressure-time curve. Reducing parameter uncertainty could be accomplished using new technologies to obtain higher quality datasets, and by gathering additional data to better define model parameter ranges for the normal eye. With additional research, we expect the pressure dependent outflow analysis described herein may find applications in the differential diagnosis, prognosis and monitoring of the glaucomatous eye

The energy loss may predict rupture risks of anterior communicating aneurysms: A preliminary result

Anterior communicating artery (ACoA) aneurysms are well documented to have a higher rupture risk compared with aneurysms at other locations. However, the risk predicting factors for these aneurysms still remain unclear due to the complex arteries geometries and flow patterns involved. The authors introduce a comprehensive method to quantitatively illustrate the development of ACoA aneurysms using a computational fluid dynamics (CFD) approach. Seven ACoA aneurysms, which included 2 ruptured and 5 unruptured aneurysms, were employed. Patient-specific whole anterior circulation geometries were segmented to simulate the real circumstances in vivo. The energy losses (EL) and flow architectures of these 7 aneurysms were evaluated using an algorithm modality. Overall, the 2 ruptured aneurysms, along with 1 unruptured aneurysm that was defined as highly likely to rupture due to ACoA location and a bleb sitting at the top of the dome, had a significantly larger EL and more complex and unstable flow architecture than the others. Two aneurysms had a negative value of EL indicating that the geometries with aneurysms of the anterior communicating complex (ACC) had a smaller loss of energy than the geometries without aneurysms. Despite a small sample size resulting in a low statistical significance, EL may serve as a development predictor of ACoA aneurysms

Dispersion-engineered silicon nitride waveguides for mid-infrared supercontinuum generation covering the wavelength range 0.8-6.5 mu m

We numerically demonstrate the generation of a mid-infrared supercontinuum (SC) through the design of an on-chip complementary metal oxide semiconductor (CMOS) compatible 10-mm-long air-clad rectangular waveguide made using stoichiometric silicon nitride (Si 3 N 4 ) as the core and MgF 2 glass as its lower cladding. The proposed waveguide is optimized for pumping in both the anomalous and all-normal dispersion regimes. A number of waveguide geometries are optimized for pumping at 1.55 μ m with ultrashort pulses of 50-fs duration and a peak power of 5 kW. By initially keeping the thickness constant at 0.8 μ m, four different structures are engineered with varying widths between 3 μ m and 6 μ m. The largest SC spectral evolution covering a region of 0.8 μ m to beyond 6.5 μ m could be realized by a waveguide geometry with a width of 3 μ m. Numerical analysis shows that increasing width beyond 3 μ m by fixing thickness at 0.8 μ m results in a reduction of the SC extension in the long wavelength side. However, the SC spectrum can be enhanced beyond 6.5 μ m by increasing the waveguide thickness beyond 0.9 μ m with the same peak power and pump source. To the best of our knowledge, this is first time report of a broad SC spectral evolution through numerical demonstration in the mid-infrared region by the silicon nitride waveguide. In the case of all-normal dispersion pumping, a flatter SC spectra can be predicted with the same power and pump pulse but with a reduced bandwidth spanning 950–2100 nm

How codes of ethics deal with fear in the workplace

The relationship between decision-making and emotions has been increasingly explored in the past thirty years by physicians, psychologists and economists. Because of the impact that emotions have on human behaviour, ethical implications need to be examined if we consider that managers could use emotions to motivate employees. This paper analyses the content of the code of ethics of 278 companies listed on the Italian stock exchange in order to verify how the codes take into account the emotion of fear experienced by employees in the workplace. Research findings revealed that companies have failed to consider the word “fear” and most of the other terms expressing similar emotions. On the other hand, their codes of ethics focused on ethical standards that should be respected, such as the dignity of each single individual and on unethical actions that must be avoided, such as acts of physical or psychological violence

A Dispositional Account of Aversive Racism

I motivate and articulate a dispositional account of aversive racism. By conceptualizing and measuring attitudes in terms of their full distribution, rather than in terms of their mode or mean preference, my account of dispositional attitudes gives ambivalent attitudes (qua attitude) the ability to predict aggregate behavior. This account can be distinguished from other dispositional accounts of attitude by its ability to characterize ambivalent attitudes such as aversive racism at the attitudinal rather than the sub-attitudinal level and its deeper appreciation of the analogy between traits and attitudes

Collective Implicit Attitudes: A Stakeholder Conception of Implicit Bias

Psychologists and philosophers have not yet resolved what they take implicit attitudes to be; and, some, concerned about limitations in the psychometric evidence, have even challenged the predictive and theoretical value of positing implicit attitudes in explanations for social behavior. In the midst of this debate, prominent stakeholders in science have called for scientific communities to recognize and countenance implicit bias in STEM fields. In this paper, I stake out a stakeholder conception of implicit bias that responds to these challenges in ways that are responsive to the psychometric evidence, while also being resilient to the sorts of disagreements and scientific progress that would not undermine the soundness of this call. Along the way, my account advocates for attributing collective (group-level) implicit attitudes rather than individual-level implicit attitudes. This position raises new puzzles for future research on the relationship (metaphysical, epistemic, and ethical) between collective implicit attitudes and individual-level attitudes