Challenge for under 40nm size pattern making for EUV mask

Abstract

Extreme Ultraviolet Lithography (EUVL) is a promising technology for the next generation lithography. It will be applied for half pitch 16nm node and beyond. The pattern resolution of recent EUV lithography is around hp20nm and next target is hp16nm. Although present requirement for EUV mask pattern resolution is hp64 nm, there is a special request to make under 40nm size pattern for EUV mask. One of examples is programmed phase defect mask (PDM).Phase defect of EUV blank affects large influence to wafer print result. Blank inspection is one of the key technology for EUV mask fabrication. To evaluate blank inspection tool, program defect mask is essential. Other examples are EUV mask for EUV diffraction exposure tool and EUV microscope evaluation. These masks need absorber pattern resolution of 30nm and smaller. In this paper, we will present process development results targeting 30nm size pattern.Programmed defect size achieved to 20nm width (FWHM: width at half maximum), 1.0nm height, both pit and bump defect. Absorber pattern resolution achieved 30nm half pitch. Not only simple dense line pattern, we fabricated radial pattern and any angle pattern.