We report on the development and first experimental results of a "at wavelength" full-field imaging technique for defect inspection of multilayer mask blanks for extreme ultraviolet (EUV) lithography. According to the International Semiconductor Roadmap by Sematech, less than 5 X 10~(-3) defects per cm~2 should be present on such multilayer mask blank to enable mass production of microelectronics using EUV lithography, thus fast high-resolution methods for mask defect inspection and localization are needed. Our approach uses a photoemission electron microscope in a normal incidence illumination mode at 13 nm to image the photoelectron emission induced by the EUV wave field on the multilayer mask blank surface. We show that by these means, buried defects in the multilayer stack can be probed down to a lateral size of 50 nm.
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机译:我们报道了用于多层掩模坯料的极紫外(EUV)光刻缺陷检测的“在波长”全场成像技术的发展和第一批实验结果。根据Sematech的《国际半导体路线图》,在这种多层掩模坯料上,每cm〜2缺陷应少于5 X 10〜(-3)个,以便能够使用EUV光刻技术大量生产微电子器件,因此快速的高分辨率掩模方法需要进行缺陷检查和定位。我们的方法在垂直入射照明模式下使用13 nm的光发射电子显微镜在多层掩模毛坯表面上成像由EUV波场引起的光电子发射。我们表明,通过这些手段,多层堆栈中的掩埋缺陷可以探查到横向尺寸为50 nm。
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