Aberration measurement of projection optics in lithographic tools based on two-beam interference theory

The degradation of image quality caused by aberrations of projection optics in lithographic tools is a serious problem in optical lithography. We propose what we believe to be a novel technique for measuring aberrations of projection optics based on two-beam interference theory. By utilizing the partial coherent imaging theory, a novel model that accurately characterizes the relative image displacement of a fine grating pattern to a large pattern induced by aberrations is derived. Both even and odd aberrations are extracted independently from the relative image displacements of the printed patterns by two-beam interference imaging of the zeroth and positive first orders. The simulation results show that by using this technique we can measure the aberrations present in the lithographic tool with higher accuracy. (c) 2006 Optical Society of America.

Aberration measurement of projection optics in lithographic tools by use of an alternating phase-shifting mask

As a critical dimension shrinks, the degradation in image quality caused by wavefront aberrations of projection optics in lithographic tools becomes a serious problem. It is necessary to establish a technique for a fast and accurate in situ aberration measurement. We introduce what we believe to be a novel technique for characterizing the aberrations of projection optics by using an alternating phase-shifting mask. The even aberrations, such as spherical aberration and astigmatism, and the odd aberrations, such as coma, are extracted from focus shifts and image displacements of the phase-shifted pattern, respectively. The focus shifts and the image displacements are measured by a transmission image sensor. The simulation results show that, compared with the accuracy of the previous straightforward measurement technique, the accuracy of the coma measurement increases by more than 30% and the accuracy of the spherical-aberration measurement increases by approximately 20%. (c) 2006 Optical Society of America.

Measurement of the diffraction-limit wavefront with double-shearing interferometers

In order to measure the diffraction-limit wavefront, we present three types of common-path double-shearing interferometers based on the theory of double shearing. Two pairs of half-aperture or whole-aperture wedge plates are used to introduce opposite tilt to realize the double-shearing function. By comparing the fringe widths in two fields, the marginal wavefront aberration can be obtained. In the paper, we give three different configurations: half-aperture configuration, whole-field configuration and double-interferometer configuration. The half-aperture configuration has the features of high sensitivity, stabilization and easy alignment. For the whole-field configuration, the interference fringes are displayed in two whole fields. Consequently, the divergent or convergent characteristic and aberration types of a wavefront can be identified visually. The whole-field configuration can be changed to the double-interferometer configuration for continuous test. Both small and large wavefront aberrations can be measured by the double-interferometer configuration. The minimum detectable wavefront aberration (W-0)(min) comes to 0.03 lambda. Lastly, we present the experimental results for the three types of double-shearing interferometers.

Phase-space analysis of wavefront coding imaging systems

We explore the use of the Radon-Wigner transform, which is associated with the fractional Fourier transform of the pupil function, for determining the point spread function (PSF) of an incoherant defocused optical system. Then we introduce these phase-space tools to analyse the wavefront coding imaging system. It is shown that the shape of the PSF for such a system is highly invarient to the defocous-related aberrations except for a lateral shift. The optical transfer function of this system is also investigated briefly from a new understanding of ambiguity function.

Study of the transmitter antenna gain for intersatellite laser communications

The gain of a transmitter for intersatellite communications is closely related to the performance of all the links. We calculate the transmitter telescope's gain with the help of the rigorous scalar diffraction theory and equivalent optical layout method. Furthermore, a comparison is performed with the conventional imaging method. The results show that the stop inside the telescope can affect the gain of the telescope. Finally, the gain is calculated under the condition of the aberrations. We find that different aberrations cause different effects. (C) 2006 Society of Photo-Optical Instrumentation Engineers.

圆孔受限波差高斯光束的远场近似及发散度分析

引入复高斯函数对衍射受限的圆孔进行了复高斯分解，得到了波差高斯光束远场衍射的近似解析式。在各种参量条件下，近似解析式所表示的衍射图样与严格的夫琅和费衍射积分的衍射图样完全一致，这表明用此解析式表征远场衍射是正确的。它的形式相对简单，为计算带来极大的方便。基于此，对有波差的高斯光束的远场发散度进行了深入的研究，检验了确定参量的光束随距离的改变而发散度不被改变的特性；同时，探讨了在圆孔限制下，发散度随高斯光束的束腰及波差的改变而变化的关系曲线，结果表明，这两个参量是影响发散度的主要因素。

Coma measurement using a PSM and transmission image sensor

As feature size decreases, especially with the use of resolution enhancement technique, requirements for the coma aberrations in the projection lenses of the lithographic tools have become extremely severe. So, fast and accurate in situ measurement of coma is necessary. In the present paper, we present a new method for characterizing the coma aberrations in the projection lens using a phase-shifting mask and a transmission image sensor. By measuring the image positions at multiple NA and partial coherence settings, we are able to extract the coma aberration. The simulation results show that the accuracy of coma measurement increases approximately 20% compared to the previous straightforward measurement technique. (c) 2005 Elsevier GmbH. All rights reserved.

Coma measurement of projection optics in lithographic tools based on relative image displacements at multiple illumination settings

In this paper, we propose a novel method for measuring the coma aberrations of lithographic projection optics based on relative image displacements at multiple illumination settings. The measurement accuracy of coma can be improved because the phase-shifting gratings are more sensitive to the aberrations than the binary gratings used in the TAMIS technique, and the impact of distortion on displacements of aerial image can be eliminated when the relative image displacements are measured. The PROLITH simulation results show that, the measurement accuracy of coma increases by more than 25% under conventional illumination, and the measurement accuracy of primary coma increases by more than 20% under annular illumination, compared with the TAMIS technique. (c) 2007 Optical Society of America.

A novel method for measuring the coma of a lithographic projection system by use of mirror-symmetry marks

A novel method for measuring the coma of a lithographic projection system is proposed and the principle of the method is described. By utilizing mirror-symmetry marks, the adverse effects of axial aberrations on the coma measurement are avoided. Experimental results demonstrated that the method has high accuracy. Compared with TAMIS, the conventional technique used for coma measurement, the method is more reliable because the influences of the process factors on the lateral displacements have been considered. (c) 2006 Elsevier Ltd. All rights reserved.

Coma measurement by use of an alternating phase-shifting mask mark with a specific phase width

The correlation between the coma sensitivity of the alternating phase-shifting mask (Alt-PSM) mark and the mark's structure is studied based on the Hopkins theory of partially coherent imaging and positive resist optical lithography (PROLITH) simulation. It is found that an optimized Alt-PSM mark with its phase width being two-thirds its pitch has a higher sensitivity to coma than Alt-PSM marks with the same pitch and the different phase widths. The pitch of the Alt-PSM mark is also optimized by PROLITH simulation, and the structure of p - 1.92 lambda/NA and pw = 2p/3 proves to be with the highest sensitivity. The optimized Alt-PSM mark is used as a measurement mark to retrieve coma aberration from the projection optics in lithographic tools. In comparison with an ordinary Alt-PSM mark with its phase width being a half its pitch, the measurement accuracies of Z(7) and Z(14) apparently increase. (C) 2009 Optical Society of America

Even aberration measurement of lithographic projection system based on optimized phase-shifting marks

In the present paper, we propose a novel method for measuring the even aberrations of lithographic projection optics by use of optimized phase-shifting marks on the test mask. The line/space ratio of the phase-shifting marks is optimized to obtain the maximum sensitivities of Zernike coefficients corresponding to even aberrations. Spherical aberration and astigmatism can be calculated from the focus shifts of phase-shifting gratings oriented at 0 degrees, 45 degrees, 90 degrees and 135 degrees at multiple illumination settings. The PROLITH simulation results show that, the measurement accuracy of spherical aberration and astigmatism obviously increase, after the optimization of the measurement mark. (C) 2008 Elsevier B.V. All rights reserved.

Gêneros múltiplos: binarismos versus pluralismo em Stone butch blues e Stella Manhattan

Gêneros múltiplos: binarismos versus pluralismo em Stone Butch Blues e Stella Manhattan almeja discutir a arbitrariedade do sistema de sexo e gênero da sociedade ocidental contemporânea, que categoriza e fixa o sexo biológico dos indivíduos em duas exclusivas expressões de gênero possíveis: homem/masculino x mulher/feminino. Casos em que a referida consonância entre sexo e gênero não ocorre são tratados como aberrações passíveis de punições físicas e morais. O corpus literário desta tese é formado por romances da literatura norte-americana (Stone Butch Blues, de Leslie Feinberg) e brasileira (Stella Manhattan, de Silviano Santiago). A introdução discorre brevemente acerca da história e da teoria do romance, objeto principal deste estudo, posta em prática por renomados romancistas. O segundo capítulo ocupa-se de questões teóricas sobre sexo e gênero, importantes para o embasamento da discussão literária, além da trama e fortuna crítica sobre Stone Butch Blues, incluindo uma análise do autor deste trabalho sobre o referido romance. O terceiro capítulo discute outras questões teóricas, desta vez sobre teoria da Literatura e de gênero, além de apresentar a fortuna crítica de Stella Manhattan, culminando também com uma análise crítica do autor desta tese sobre o romance brasileiro. Ao final da pesquisa, objetiva-se demonstrar que o binário de gênero socialmente imposto precisa, em realidade, ceder espaço a um sistema plural e fluido, no qual a biologia perde seu papel determinante na masculinidade ou feminilidade do indivíduo

A apropriação da monstruosidade pelo saber médico.

O trabalho tem por objetivo descrever como o discurso em torno das deformidades é resultante de um processo, iniciado no século XIX, que deslocou o fenômeno da monstruosidade dos registros das aberrações descritas moral ou religiosamente para o campo da Biologia. A hipótese é a de que houve uma apropriação médica da monstruosidade guiada principalmente por três vetores: desenvolvimento da Teratologia como ciência; mudança das sensibilidades e o surgimento do sentimento de compaixão, estimulado em grande parte pela literatura do século XIX; e o aumento do número de pessoas deficientes, em decorrência da Primeira e da Segunda Guerras Mundiais, que levou a uma mudança na forma como as sociedades lidavam com um corpo marcado pela deformidade. Tanto a Teratologia, como a literatura foram operadores importantes no processo de conscientização sobre a humanidade dos monstros. É justamente essa transição de uma categoria social de monstro para a categoria social de portador de deformidade, construída pelo saber médico, que o trabalho pretende investigar.

Genotoxic effect of nickel chloride and zinc sulphate on fish Hypophthalmichthys molitrix

The present investigation is to assess the genotoxic potential of nickel chloride and zinc sulphate on gill cells of silver carp Hypophthalmichthys molitrix. Fishes were exposed in sublethal concentration of nickel chloride 5. 7 mg/1 and zinc sulphate 6.8 mg/1, and sampled at 10, 20 and 30 days. Nickel chloride and zinc sulphate treated fishes exhibited an apparent increase in the aberration frequency and a decrease in the mitotic index as compared to control. Acentric fragment, chromatid break, endoreduplication, chromatid gap, centromeric fusion, ploidy, sticky plate, dicentric chromosome, clumping and partial sticky plates were some of the abnormalities observed. The chromosomal aberrations in the treated fishes were significant compared to control.

Aberration correction in Spatial Light Modulator based mode multiplexers

The Spatial Light Modulator in a mode demultiplexer is used to measure the aberrations of the system in which it is installed before applying aberration correction to improve the insertion loss and modal extinction ratios. © 2013 OSA.