Optical proximity effects

The linewidth differences between the mask and the corresponding resist pattern were precisely evaluated for isolated line and isolated space patterns. The deviation in linewidth versus linewidth shows a maximum or minimum with inorganic resists (13). This behavior is in contrast to that for organic polymeric resists, in which the linewidth deviations gradually increase as the mask feature size decreases. This difference may be explained in terms of selfcompensation of the optical proximity effect due to lateral Ag diffusion. 

Two paradigms have been widely used in the past decade to describe the ultrafast relaxation of optically excited tttt states in purine molecules, through internal conversions [69], One of them relies on the existence of a conical intersection (Cl) between the excited state and the ground state, accessible on the excited state surface from the Franck-Condon region [69, 70], The second one, Lim s proximity effect , stems from vibronic coupling between the tttt state and nearby mr states found in these heteroatomic molecules [71]. Excited state quantum calculations have therefore focused recently on a precise characterisation of the strong perturbations and interactions undergone by these tttt or nit states. 

This account has focused on the role of environmental - or proximity - effects on the THz vibrational spectra of DNA as well as on the vibrational spectra of manmade nanostractures used in the study of the vibrational, electronic, and optical properties of DNA. Based on the results presented in this account, many factors are responsible for such effects these include electrolytic concentrations, materials in the proximity of the nanostractures under consideration, and the sequence of DNA bases. 

In general, laser writers offer some unique advantages. With multiple laser beams (up to 32 in some systems), these systems are capable of high throughput and are therefore considerably faster than their electron-beam-writer counterparts. They are also more accurate than electron-beam writers because they are more stable, a consequence of the facts that electrons are very sensitive to magnetic fields and also tend to scatter. The very small effective address unit is useful for fine adjustment of line widths on the mask, which makes it easier to implement optical proximity correction schemes in these masks than in masks produced from other mask writers. Furthermore, laser writers operating at 364-nm and... 

We present here a condensed explanation and summary of the effects. A complete discussion can be found in a paper by Hellen and Axelrod(33) which directly calculates the amount of emission light gathered by a finite-aperture objective from a surface-proximal fluorophore under steady illumination. The effects referred to here are not quantum-chemical, that is, effects upon the orbitals or states of the fluorophore in the presence of any static fields associated with the surface. Rather, the effects are "classical-optical," that is, effects upon the electromagnetic field generated by a classical oscillating dipole in the presence of an interface between any media with dissimilar refractive indices. Of course, both types of effects may be present simultaneously in a given system. However, the quantum-chemical effects vary with the detailed chemistry of each system, whereas the classical-optical effects are more universal. Occasionally, a change in the emission properties of a fluorophore at a surface may be attributed to the former when in fact the latter are responsible. 

The electromers differ drastically in their optical and ESR spectra. There is a rather small energy difference between them (ca. 1 eV). The authors conclude that the experimentally found energetic proximity of the two states is not an intrinsic property of the diaryldiazo cation radicals, but must be due to some solvent and/or counterion effects acting to preferentially stabilize the o-state by about 1 eV. These effects, however, failed to be identified in the quoted paper. We await further development of the problem. 

The operation of proximity sensors can be based on a wide range of principles, including capacitance, induction, Hall and magnetic effects variable reluctance, linear variable differential transformer (LVDT), variable resistor mechanical and electromechanical limit switches optical, photoelectric, or fiber-optic sensors laser-based distance, dimension, or thickness sensors air gap sensors ultrasonic and displacement transducers. Their detection ranges vary from micrometers to meters, and their applications include the measurement of position, displacement, proximity, or operational limits in controlling moving components of valves and dampers. Either linear or angular position can be measured ... 

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