4 March 2008 Exposure tool specific post-OPC verification
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The evolution of high-NA projection optics design and manufacturing tolerances has been remarkable in recent years. Nevertheless, different instances of identical scanner models can still exhibit unique optical fingerprints which can impart subtle patterning differences for a given mask exposed at nominally identical conditions on different scanners. In some cases, a product can be shown statistically to yield lower when a certain layer is exposed on a particular scanner. Thus it is common to have a certain subset of the total population of tools allowed for certain critical levels, such as gate. Since a single mask is typically shared between the multiple allowed scanners, the optical proximity correction model which is employed in the generation of that mask must represent the average fingerprint of those tools. In practice, CD data may be collected from multiple tools, but more often a single tool is somehow identified as the "golden" tool for the purpose of calibrating the OPC model. Once the mask is generated, however, its printing behavior on multiple scanners can readily be simulated using tool-specific optical models. Such models can be easily generated based upon known optical fingerprint data, such as measured illumination source maps, Jones pupil or Zernike aberration files. This paper investigates the use of tool-specific optical models to elucidate the intersection of design and process variability, which will manifest differently on each scanner, depending upon subtle details of the scanner fingerprint.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
John Sturtevant, John Sturtevant, Srividya Jayaram, Srividya Jayaram, Le Hong, Le Hong, "Exposure tool specific post-OPC verification", Proc. SPIE 6925, Design for Manufacturability through Design-Process Integration II, 69250T (4 March 2008); doi: 10.1117/12.773340; https://doi.org/10.1117/12.773340

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