18 May 2007 Application of Sigma7500 pattern generator to X architecture and 45-nm generation mask making
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Proceedings Volume 6607, Photomask and Next-Generation Lithography Mask Technology XIV; 660705 (2007) https://doi.org/10.1117/12.728919
Event: Photomask and Next-Generation Lithography Mask Technology XIV, 2007, Yokohama, Japan
The mask cost is increasing substantially from generation to generation. Hence, reducing the mask cost is one of the most critical needs in developing a new generation of technology. Compared with variable shaped beam (VSB) e-beam tools, laser writers have the advantage of higher throughput and lower cost. Moreover, the writing time is not dependent on feature count but on the area written. Additionally the FEP-171 resist, which is used for the DUV laser writer, is also the resist used for VSB writers. This enables process sharing and reduces the number of processes needed for mask manufacturing. Finally the laser writer is expected to print Manhattan and X-architecture features with no major differences. Whereas, VSB e-beam tools take longer to write, if X features are included with Manhattan-type features. The inclusion of X features also worsens CD uniformity when written with VSB e-beam tools. The Sigma7500 DUV laser writer uses partially coherent imaging of a spatial light modulator (SLM) to maximize resolution, while providing 4-pass and 2-pass printings, corner enhancement, and grid matching. These functions are evaluated and the results are reported in this paper. Evaluation data shows that the global CD uniformity of dense line/space and isolated spaces is around 6 nm (3σ) for features at 0-, 45-, 90-, and 135-degree angles, which are used in the X architecture. The resolution of lines and spaces can both reach 150 nm. Based on our evaluation, the Sigma7500 can meet both critical 65-nm and sub-critical 45-nm generation mask specifications and reduces the writing cost by 40%. The writing time for X architecture patterns can be reduced by at least a factor of two as compared to VSB systems, while the CD performance remains comparable. However, the pattern fidelity is slightly worse and the CD of 45- and 135-degree lines is difficult to adjust independently. In addition, the Sigma7500 comes with a data-sizing function (ProcessEqualizer) to compensate for global CD signatures, but the potential impact of data sizing on OPC accuracy is a concern and it must be evaluated. Evaluation data shows that the Sigma7500 is capable of 45-nm node sub-critical mask production. Its advantages in high productivity and acceptable CD control should provide a solution to reduce the mask cost of advanced nodes.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ming-Jiun Yao, Ming-Jiun Yao, Tzu-Yi Wang, Tzu-Yi Wang, Chia-Jen Chen, Chia-Jen Chen, Hsin-Chang Lee, Hsin-Chang Lee, Yao-Ching Ku, Yao-Ching Ku, } "Application of Sigma7500 pattern generator to X architecture and 45-nm generation mask making", Proc. SPIE 6607, Photomask and Next-Generation Lithography Mask Technology XIV, 660705 (18 May 2007); doi: 10.1117/12.728919; https://doi.org/10.1117/12.728919


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