| Popis: |
We manufactured LEEPL masks for 65-nm node and evaluated the masks for the critical dimension (CD), image placement (IP) and defects. Although the CD uniformity was 8.0 nm (3σ), an improvement is promising by resist upgrading. The CD linearity was within 5 nm (3σ) through the range of 80- to 300-nm width and the 65-nm hole patterns were successfully resolved. The local and global IP errors obtained were 23.2/16.4 nm and 8.76/6.66 nm (in the x/y directions), respectively. A defect inspection was conducted and detected defects were classified. Most of the defects were miss-placement and miss-size, which seemed to be non-killer defects. On the other hands, foreign materials that must be killer defects were analyzed using energy dispersion X-ray (EDX) and found that they consist of Si. Si fragments mainly came from strut walls and by employing new backside-etching conditions, we improved roughness of strut walls. As a result, no closed defects were detected. |
