High performance mask fabrication process for the next-generation mask production

Abstract

ArF immersion lithography combined with double patterning has been used for fabricating below half pitch 40nm devices. However, when pattern size shrinks below 20nm, we must use new technology like quadruple patterning process or next generation lithography (NGL) solutions. Moreover, with change in lithography tool, next generation mask production will be needed. According to ITRS 2013, fabrication of finer patterns less than 15nm will be required on mask plate in NGL mask production 5 years later [1]. In order to fabricate finer patterns on mask, higher resolution EB mask writer and high performance fabrication process will be required. In a previous study, we investigated a potential of mask fabrication process for finer patterning and achieved 17nm dense line pattern on mask plate by using VSB (Variable Shaped Beam) type EB mask writer and chemically amplified resist [2] [3]. After a further investigation, we constructed higher performance mask process by using new EB mask writer EBM9000. EBM9000 is the equipment supporting hp16nm generation's photomask production and has high accuracy and high throughput. As a result, we achieved 15.5nm pattern on mask with high productivity. Moreover, from evaluation of isolated pattern, we proved that current mask process has the capability for sub-10nm pattern. These results show that the performance of current mask fabrication process have the potential to fabricate the next-generation mask.

Effect of thermalization distance on chemical gradient of line-and-space patterns with 7 nm half-pitch in chemically amplified extreme ultraviolet resists

“…Although the resolution blur caused by the acid diffusion is a problem intrinsic to the concept of chemical amplification, 2,3) the resolution has been markedly improved to sub-16 nm by suppressing the acid diffusion using quenchers. [4][5][6][7] Such improved resolution was demonstrated by fabricating the line-and-space patterns with extremeultraviolet (EUV) or electron beam (EB) exposure tools. With the progress in the resolution, the feasibility of sub-10 nm half-pitch fabrication has recently attracted much attention from the viewpoint of the extendibility of EUV lithography.…”