Improving Overlay Accuracy Performance of Electron-Beam 2nd Writing for Advanced Photomasks
碩士 === 國立臺北科技大學 === 材料及資源工程系研究所 === 98 === Development of 45 nm node reticles has been completed at most mask shops. The development of next generation 32 nm node and beyond reticles is currently underway. Electron-beam multi-writing can provide higher precision alignment than traditional laser tool...
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| Format: | Others |
| Language: | zh-TW |
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2010
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| Online Access: | http://ndltd.ncl.edu.tw/handle/wh4dp9 |
| Summary: | 碩士 === 國立臺北科技大學 === 材料及資源工程系研究所 === 98 === Development of 45 nm node reticles has been completed at most mask shops. The development of next generation 32 nm node and beyond reticles is currently underway. Electron-beam multi-writing can provide higher precision alignment than traditional laser tool. In many advanced mask manufacturing processes, double or multi-writing process using electron beam is often required. This means that the overlay accuracy of masks becomes very crucial. The mask overlay accuracy impacts both the lithographic performance and mask manufacturability. The high-resolution lithography thus requires even tighter specifications on pattern placement of reticles in comparison with previous generation process.
RIM structure is one of the Chrome-less Phase Lithography (CPL) structures, and CPL is a promising technology among the resolution enhancement technologies (RET) for 32 nm node reticles and beyond. To improve mask-making precision and to achieve higher mask pattern resolution, we present an optimized method of mark alignment in this study. The overlay precision of the 1st and 2nd layers can be reduced to a 3σvalue of 4 nm or below. This mask overlay accuracy has met the requirements of 32 nm node reticles.
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