A series of 1-aryl-2-p-toluenesulfonyl hydrazides were synthesized by microwave irradiation under solvent-free conditions. The regioselectivity was excellent, the reaction time was short, the yields were moderate to high (64–91%), and the manipulation process was simple.
Error calibration is one of the most important factors to realize the quadri-wave lateral shearing interferometer (QWLSI) with high accuracy. The misalignment errors of QWLSI, such as the tilt of grating and the tilt of charge coupled device (CCD), will affect the measurement accuracy. The astigmatism errors induced by the tilt of grating and CCD during the alignment process of QWLSI, which are neglected in previous studies, are analyzed and presented in analytical expressions in this paper. Firstly, the additional phase difference in X and Y directions induced by the tilt of grating and CCD are analyzed using the optical wave interference theory. Representing the phase difference in the two directions and the test wavefront with the combinations of Zernike polynomials respectively, we further obtain the analytical expressions between the Zernike coefficients of the phase difference and the Zernike coefficients of the test wavefront, according to the wavefront reconstruction theory. Then the analytical expressions for the measurement errors induced by the tilt of grating and CCD, which are mainly astigmatism, can be obtained. The analytical results show that the misalignment induced astigmatism errors are inversely proportional to the shearing ratio and proportional to the tilt angle of grating and CCD. The alignment experiment of a home-made QWLSI under null test condition is conducted to verify the correctness of the theoretical analysis. With different shearing ratios for the QWLSI, the astigmatism errors, which are induced by the tilt of grating in experimental results, are consistent with the theoretical analysis results. This paper can provide technical support for the alignment of QWLSI with small shearing ratio and high precision.
Extreme ultraviolet (EUV) lithography is the most promising successor of current deep ultraviolet (DUV) lithography. The very short wavelength, reflective optics, and nontelecentric structure of EUV lithography systems bring in different imaging phenomena into the lithographic image synthesis problem. This paper develops a gradient-based inverse algorithm for EUV lithography systems to effectively improve the image fidelity by comprehensively compensating the optical proximity effect, flare, photoresist, and mask shadowing effects. A block-based method is applied to iteratively optimize the main features and subresolution assist features (SRAFs) of mask patterns, while simultaneously preserving the mask manufacturability. The mask shadowing effect may be compensated by a retargeting method based on a calibrated shadowing model. Illustrative simulations at 22 and 16 nm technology nodes are presented to validate the effectiveness of the proposed methods.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Source optimization (SO) is one of the important resolution enhancement techniques (RETs) in computational lithography. The anamorphic magnification high-numerical aperture (NA) extreme ultraviolet (EUV) lithography can achieve a higher resolution by increasing the NA. However, the increase in NA leads to a significant mask three-dimensional (M3D) effects in the partial direction on the mask, and traditional Kirchhoff model no longer works. In this paper, we propose a SO method for 0.55 NA EUV lithography based on thick mask model. The results demonstrate that thick mask model aware SO can effectively mitigate the M3D effects, achieve high fidelity patterns, and enlarge the process window (PW). The depth of defocus (exposure latitude=10%) of thick mask model aware SO at two types of target patterns is 52nm and 67nm, which is 116.7% and 48.9% larger than that of thin mask model aware SO.
We studied the dependence of light-induced absorption on temperature in reduced Co:KNSBN crystal. The changes of light-induced absorption decrease as temperature decrease at high pump intensity, which can not be explained by previous two centers model. The dynamic behaviors of light-induced absorption reveal that there are multiple shallow levels in crystals. The thermal exciting rate and active energy of shallow levels are determined by the dependence of dynamics of light-induced absorption on pump intensity and temperature, respectively. The deep levels of reduced Co:KNSBN can be shown in transmission spectra of crystal. A model assuming both electron and hole with three shallow traps is used to explain our experimental results.
As the critical dimension of integrated circuits is continuously shrunk, thick mask induced aberration (TMIA) cannot be ignored in the lithography image process. Recently, a set of pupil wavefront optimization (PWO) approaches has been proposed to compensate for TMIA, based on a wavefront manipulator in modern scanners. However, these prior PWO methods have two intrinsic drawbacks. First, the traditional methods fell short in building up the analytical relationship between the pupil wavefront and the cost function, and used time-consuming algorithms to solve for the PWO problem. Second, in traditional methods, only the spherical aberrations were optimized to compensate for the focus exposure matrix tilt and best focus shift induced by TMIA. Thus, the degrees of freedom were limited during the optimization procedure. To overcome these restrictions, we build the analytical relationship between the pupil wavefront and the cost function based on Abbe vector imaging theory. With this analytical model and the Fletcher-Reeves conjugate-gradient algorithm, an inverse PWO method is innovated to balance the TMIA including 37 Zernike terms. Simulation results illustrate that our approach significantly improves image fidelity within a larger process window. This demonstrates that TMIA is effectively compensated by our inverse PWO approach.
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