Extreme ultraviolet mask observations using a coherent extreme ultraviolet scatterometry microscope with a high-harmonic-generation source. (26th May 2015)

• Record Type: Journal Article
• Authors: Fujino, Takahiro; Tanaka, Yusuke; Harada, Tetsuo; Nagata, Yutaka; Watanabe, Takeo; Kinoshita, Hiroo
• Is Part Of: Japanese journal of applied physics. Volume 54:Number 6(2015:Jun.)Supplement 1
• Publication Date: 2015-05-26
• Subjects: Physics -- Periodicals; 621.05
• DOI: 10.7567/JJAP.54.06FC01
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: In extreme ultraviolet (EUV) lithography, the three-dimensional structure of an EUV mask, which has an absorber layer and a Mo/Si multilayer on a glass substrate, strongly affects the EUV phase. We have developed a coherent EUV scatterometry microscope (CSM) to observe EUV patterns with a quantitative phase contrast based on the coherent-diffraction-imaging method, which is a simple system without an objective. A coherent stand-alone high-harmonic-generation (HHG) EUV source has been developed for practical use. Although the throughput of the relay optics in the previous study was insufficient to compensate for the fluctuation of the beam position, herein the beam position is stabilized and the relay optics are upgraded, increasing the throughput of the EUV power 130-fold. Consequently, the detection time for the same defect size is markedly reduced from 1000 to 1 s. Furthermore, a 52 × 52 nm 2 absorber defect is detected in 10 s.