The stochastic effect in contact single patterning is one of the primary challenges in extending into sub-40nm pitch with 0.33NA EUV. EUV stochastic defects induced by EUV photon shot noise are known to strongly correlate to image contrast. Mitigation of Mask3D induced contrast fading is one of the key solutions to enable further shrink, while maintaining sufficient defect-free process latitude. Wavefront and pupil co-optimization is designed to compensate the Mask 3D phase error that leads to contrast fading. For application in HVM, the newly developed Pupil/Mask/Wavefront co-optimization gives the best imaging performance while maintaining the illumination efficiency and decreasing the rms wavefront for the final optimal wavefront to ensure there is no negative impact on the rest of the patterns that are not included in the optimization. In this paper, we investigate how to apply Pupil/Mask/Wavefront co-optimization to improve the image contrast of a sub-40nm pitch contact hole array, including in-resist verification. We will first explain the fundamentals of Mask 3D fading mitigation via phase injection for a 1D feature and how to extend this concept to 2D features. We will compare the effectiveness of new Pupil/Mask/Wavefront co-optimization versus Zernike Z5 or Z6 only phase injection method. Finally, we will show the potential benefit in combination with using a low-n phase shifting mask for which the optimum image contrast is achieved with the co-optimized wavefront, pupil and mask.
The EUV High-NA scanner brings innovative design changes to projection optics, such as introducing center obscuration and the anamorphic projection optical system in the projection optics box (POB) to improve the system transmission while the NA is improved1 . These design changes need to be accounted for in the computational lithography software solutions, to ensure accurate modeling and optimization of the High-NA system performance on wafer. In this paper, we will systematically investigate the benefits of Source Mask Optimization (SMO) and mask only optimization to explore EUV High-NA full chip patterning solutions, where mask 3D effects (M3D) are captured in the optical modeling. The paper will focus on assessing the performance (including process window, depth of focus, normalized image log slope) of through-pitch 1D Line/space (L/S) patterns and 2D Contact/Hole (CH) patterns after aforementioned optimizations and demonstrate the impact of center obscuration on imaging. In addition, we will investigate the effect of sub-resolution assistant feature (SRAF) on High-NA patterning via comparing the optimized lithographic performance with and without SRAF. These findings will help determine the most optimal patterning solutions for EUV High-NA as we move towards the first High NA EUV insertion. The paper will also discuss the anamorphic SMO where MRC and mask description needs to change from wafer plane (1x1) to scaled reticle plane (1x2). The interfield stitching will also be briefly discussed in this paper.
We demonstrated flat-field illumination (FFI) for multi-color wide-field fluorescence microscopy using a refractionbased beam shaping system. The non-homogeneous illumination of a Gaussian intensity profile makes quantitative analysis in laser-assisted wide-field fluorescence microscopy very difficult. As contrasted with other approaches, our method is applicable to TIRF illumination, which effectively rejects background fluorescence.
Our beam shaping device is extremely tolerant to variations in size of the incoming laser beam by accepting ± 10% variation, while being achromatic as well. This behavior originates from the well-balanced mapping of the incoming rays to the intended flattop beam profile in combination with a sophisticated material choice, which decreases the sensitivity to input beam diameter. The homogenous illumination profile of FFI will enable quantitative single-molecule analysis based on intensity information. This has powerful implications when combined with a pull-down assay, which can probe the oligomerization state of endogenous proteins. When combined with one-to-one fluorophore labeling, the stoichiometry of proteins related to neurodegenerative diseases could be readily determined by intensity distribution analysis, which is critical to not only diagnosing but also understanding the pathogenesis of these complex disorders that are particularly difficult to analyze.
An additional application of FFI is high quality super-resolution imaging with a uniform spatial resolution over a large FOV, where the full power of the excitation beam could be utilized. A new optical design approach based on refractive freeform surfaces generating a square-shaped beam instead of a round one will be presented, which would yield greater illumination efficiency.
We demonstrated flat-field illumination (FFI) for multi-color wide-field fluorescence microscopy using a refractionbased beam shaping system. The non-homogeneous illumination of a Gaussian intensity profile makes quantitative analysis in laser-assisted wide-field fluorescence microscopy very difficult. As contrasted with other approaches, our method is applicable to TIRF illumination, which effectively rejects background fluorescence. Our beam shaping device is extremely tolerant to variations in size of the incoming laser beam by accepting ± 10% variation, while being achromatic as well. This behavior originates from the well-balanced mapping of the incoming rays to the intended flattop beam profile in combination with a sophisticated material choice, which decreases the sensitivity to input beam diameter. The homogenous illumination profile of FFI will enable quantitative single-molecule analysis based on intensity information. This has powerful implications when combined with a pull-down assay, which can probe the oligomerization state of endogenous proteins. When combined with one-to-one fluorophore labeling, the stoichiometry of proteins related to neurodegenerative diseases could be readily determined by intensity distribution analysis, which is critical to not only diagnosing but also understanding the pathogenesis of these complex disorders that are particularly difficult to analyze. An additional application of FFI is high quality super-resolution imaging with a uniform spatial resolution over a large FOV, where the full power of the excitation beam could be utilized. A new optical design approach based on refractive freeform surfaces generating a square-shaped beam instead of a round one will be presented, which would yield greater illumination efficiency.
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