24 September 2010 A systematic approach to the determination of SRAF capabilities in high end mask manufacturing
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The continued shrink of integrated circuit patterns increases the demand for reticle enhancement techniques (RET). The application of Sub Resolution Assist Features (SRAFs) is pushing mask processes to the resolution limit. Many Chemically Amplified Resists (CAR) used in current photomask processes do not have the capability to fully meet the current demand for SRAF resolution. Often the resulting quality of small SRAFs suffers from pattern fidelity limitations like Line End Shorting (LES) and corner rounding. While small SRAFs might physically resolve on the mask, these limitations cause massive nuisance detections at defect inspections. In a productive environment, high levels of nuisance detections are not acceptable due to the cycle time impact from classification and review. The AMTC systematically investigated the SRAF capability of different mask processes in order to better understand the process limitations as well as to predict the manufacturability of customer patterns. This investigation uses high sensitivity inspections of a specially designed test pattern to determine the SRAF capability limits. An overview of the predicted SRAF capabilities for different resists and blank substrates is provided along with verification on customer layouts.
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Christian Bürgel, Christian Bürgel, Martin Sczyrba, Martin Sczyrba, G. R. Cantrell, G. R. Cantrell, } "A systematic approach to the determination of SRAF capabilities in high end mask manufacturing", Proc. SPIE 7823, Photomask Technology 2010, 78230I (24 September 2010); doi: 10.1117/12.864210; https://doi.org/10.1117/12.864210


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