Multilayer reflective coatings for extreme-ultraviolet lithography

被引：117

作者：

Montcalm, C ^{[1
]}

Bajt, S ^{[1
]}

Mirkarimi, PB ^{[1
]}

Spiller, E ^{[1
]}

Weber, FJ ^{[1
]}

Folta, JA ^{[1
]}

机构：

[1] Univ Calif Lawrence Livermore Natl Lab, Adv Microtechnol Program, Livermore, CA 94550 USA

来源：

EMERGING LITHOGRAPHIC TECHNOLOGIES II | 1998年 / 3331卷

关键词：

extreme ultraviolet (EUV) lithography; reflective coatings; multilayers; reflectance; stress; radiation stability; sputtering deposition; uniformity; reproducibility;

D O I：

10.1117/12.309600

中图分类号：

TM [电工技术]; TN [电子技术、通信技术];

学科分类号：

0808 ; 0809 ;

摘要：

Multilayer mirror coatings which reflect extreme ultraviolet (EUV) radiation are a key enabling technology for EUV lithography. Mo/Si multilayers with reflectances of 67.5% at 13.4 nm are now routinely achieved and reflectances of 70.2% at 11.4 nm were obtained with Mo/Be multilayers. High reflectance is achieved with careful control of substrate quality, layer thicknesses, multilayer materials, interface quality, and surface termination, Reflectance and film stress were found to be stable relative to the requirements for application to EUV lithography. The run-to-run reproducibility of the reflectance peak position was characterized to be better than 0.2%, providing the required wavelength matching among the seven multilayer-coated mirrors used in the present lithography system design. Uniformity of coating was improved to better than 0.5% across 150 mm diameter substrates. These improvements in EUV multilayer mirror technology will enable us to meet the stringent specifications for coating the large optical substrates for our next-generation BW lithography system.

引用

页码：42 / 51

页数：10