Lithographic performance of a new 'low-k' mask

We have been researching new mask blank materials for the next generation lithography (NGL) and developed a new mask blank with low-k phase shifter [1] [2]. The low-k phase shifter consists of only Si and N. In our previous work, we reported the advantages of developed SiN phase shift mask (PSM) [2]. It showed high lithographic performance and high durability against ArF excimer laser as well as against cleaning. In this report, we further verified its high lithographic performance on several types of device pattern. The SiN PSM had high lithographic performance compared with conventional 6% MoSi PSM. Exposure latitude (EL) and mask enhancement factor (MEEF) were especially improved on originally designed Gate, Metal and Via patterns.