| Popis: |
A new exposure technology called IDEAL (Innovative Double Exposure by Advanced Lithography) which realizes k1 equals 0.3 optical lithography is introduced. In IDEAL exposure method, rough pattern mask and fine pattern mask are used. The rough pattern mask contributes to expand the degree of freedom in two-dimensional patterning and the fine pattern mask contributes to higher resolution and focus DOF enhancement. As an actual example, 120 nm gate array is formed using KrF 0.63 NA stepper. It has been confirmed that the double exposure method is effective in the pattern formation of irregularly arranged contact hole arrays of 150 nm. Furthermore, it is also shown that double exposure method is effective in the reduction of mask error enhancement factors (MEF). |
