Abstract
High-volume maskless lithography systems typically operate by raster-scanning a large array of focused radiation spots across an exposure surface while the spot intensities are modulated. This paper outlines a design concept and optical simulation results for a spot-scanning extreme ultraviolet (EUV) system using a 10×-reduction, flat-image Schwarzschild projection system consisting of only two mirrors. The spots are generated in the system's object space by means of blazed, multilevel zone-plate microlenses configured as Schupmann achromatic doublets, which are highly efficient and are designed to nullify geometric aberration in the projection system. Coherent proximity effects are eliminated by partitioning the exposure radiation into discrete, diffraction-limited image spots, which have convergence cones of numerical aperture 0.3 at the 13.5-nm operating wavelength. The image spot separation is 2.5 μm, and the spot array covers a 10-mm square image field, sufficient to achieve printing throughput of order 30 (300-mm) wafers per hour. For simplicity, the spot intensities are all controlled by a single source modulator, allowing printing of 2.5 -μm periodic patterns without a spatial light modulator. The microlens manufacturing technology would be similar to that used for EUV mirrors and phase-shift masks, but with dramatically less stringent tolerance requirements.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
