No abstract

To investigate the possibility to catch up the NGL mask pattern size scaling strategy which indicated in ITRS2012, the performance of conventional mask fabricating process was examined. Current EB resist used for mask fabrication doesn't have enough performance to resolve below hp20nm pattern. With newly developed CAR resist, the resolution limit reached to hp18nm pattern. Furthermore by using higher performance EB writer, the possibility to resolve up to hp16nm pattern was showed. The impact of proximity effect to the resist performance was examined. The resist damage induced by proximity effect degrades the resolution limit about 2nm. This is a serious problem for NGL mask manufacturing. Reducing the impact of proximity effect is one of the major challenges for developing higher resolution EB resist.

No 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.

No abstract