Mitigation of ion and particulate emission from laser-produced plasmas used for extreme ultraviolet lithography
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- 作者：Paolo Di Lazzaro ; paolo.dilazzaro@enea.it ; Sarah Bollanti ; Francesco Flora ; Luca Mezi ; Daniele Murra ; Amalia Torre
- 关键词：Extreme ultraviolet lithography ; Laser-plasma sources ; Excimer lasers ; Debris mitigation systems
- 刊名：Applied Surface Science
- 出版年：2013
- 出版时间：1 May, 2013
- 年：2013
- 卷：272
- 期：Complete
- 页码：13-18
- 全文大小：1041 K
文摘
While developing a laboratory-scale micro-exposure tool for extreme ultraviolet (EUV) projection lithography which uses a laser-produced plasma emitting EUV pulsed radiation, we faced the problem of suppressing the various debris (ions, neutrals, particulate, clusters, droplets) emitted by the plasma target. The suppression of debris is a crucial task in the frame of EUV projection lithography, mainly because debris seriously limit both lifetime and performance of the expensive optics and filters put close to the plasma source. In this paper we present the experimental measurements of main debris characteristics (velocity, size, charge, momentum, spectral energy, spatial distribution). Then, we present the operating results of a patented debris mitigation systems (DMS) specifically designed to suppress debris with the measured characteristics. We achieved reduction factors ¡«800 for atoms and nm-size clusters, and ¡«1600 for particles larger than 500 nm. These results are at the forefront in this field. The excellent performance of our DMS was a breakthrough to achieve a 90-nm patterning on commercial resists by our micro-exposure tool EUV projection lithography.