Selete's EUV program: progress and challenges

Abstract

Selete launched a development program on EUV lithography and related mask technology in April 2006. The program is based on the concept of "lithography design and integration." It covers a wide range of areas that require further effort to get EUVL ready for volume production and was formulated on the basis that the issues should be considered from a variety of standpoints, such as acceleration of the development of key lithographic components, verification that EUVL is actually suitable for mass production, the construction of mask infrastructure, and the improvement of EUV-specific reliability and productivity. Two exposure tools have been installed as basic infrastructure: the small-field exposure tool (SFET) and the full-field exposure tool (EUV1). The objectives of the SFET installation are acceleration of the development of resist materials and processes, optimization of the mask structure and materials, and the evaluation of the exposure tool technology with regard to such things as imaging performance, stability, and the lifetimes of the optics and source components. The objective of the EUV1 installation is to demonstrate that lithography integration is a viable path to making EUV lithography a practical production technology. We found that the SFET provides both excellent resolution and high tool activity. This high performance helps us to obtain a clear understanding of the current level of EUVL performance and enables us to learn many things that can be fed back into the development program in the beta stage. A 1st static exposure with the EUV1 resolved 30-nm dense and isolated lines and 30-nm holes. The potential resolution was found to be as good as 28 nm. Although progress was made regarding EUV resist sensitivity and LWR, further progress is needed. A tool for analyzing out-gassing in EUV resists was found to facilitate the development of both resist materials and contamination control measures for exposure tools. A prototype full-field actinic inspection system for mask blanks is now under development and should become operational in the 2Q of 2008. A mask protection engineering (MPE) tool was used to show that a dual-pod carrier is very effective in protecting a mask from particles. Mask pattern defect inspection technology using a DUV wavelength of 199 nm and defect repair technology based on an FIB for EUV mask fabrication are also being developed. This work was supported in part by NEDO.

Resist Parameter Extraction from Line-and-Space Patterns of Chemically Amplified Resist for Extreme Ultraviolet Lithography

“…SFET was manufactured by Canon and EUVA and installed in Selete to develop mask, resist, and tool technologies. 21,22) The exposure condition was annular illumination ( ¼ 0:3=0:7). The exposure dose was changed from 8.0 to 14.0 mJ cm À2 in steps of 0.5 mJ cm À2 .…”

Development of EUV lithography tools at Nikon

“…EUV1 has already installed in Selete (Semiconductor Leading Edge Technologies, Inc.) and is operating for EUV lithography process development [5]. In the SPIE Advanced Lithography 2008 conference, the first static exposure results with EUV1 were presented [4,5,6]. Dense lines with 28nm L/S and dense contact holes with 28nm half pitch were clearly resolved.…”

Development status of EUV resist materials and processing at Selete

“…The Selete research and development program evaluates the feasibility of the EUV lithography process for manufacturing semiconductor devices 8 . Here, we conducted a yield analysis for hp-3x-nm and hp-2x-nm test chips by using the EUV1 (Nikon) full-field exposure tool 9,10 .…”