29 June 1998 Thin-film interference effects for thin resist films on a broadband scanner
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Proceedings Volume 3334, Optical Microlithography XI; (1998); doi: 10.1117/12.310800
Event: 23rd Annual International Symposium on Microlithography, 1998, Santa Clara, CA, United States
The relative benefit of using a broadband illumination system to reduce thin-film interference is impacted when using thinner resist films. For example, with a 1 micrometer resist film, a 43% reduction in swing curve is predicted for broadband vs. monochromatic illumination, while for a 0.5 micrometer film the reduction is only 25%. For a 0.5 micrometer resist film over an organic ARC exposed on a broadband system, such as a SVGL Micrascan-2, both simulations and experimental data show a 10 - 16% swing curve. These are results for an ARC with a relatively low absorbance (k equals .22). Results are given for several approaches that were investigated to reduce this swing curve, including improved ARC materials and resist thickness optimization; e.g., with a CVD ARC, the swing curve can be reduced to less than 10 nm. Resist and ARC thickness optimizations are normally done independently; however, resist and ARC thicknesses may not be independent. Much of the thickness variation is caused by the topography, with the resist and ARC behaving in the same qualitative fashion (e.g., both the ARC and resist tend to planarize over a ridge; thus, both will be thinner over a ridge). A method for optimizing interdependent resist and ARC thicknesses is also presented; it couples modeled linewidth data with ARC and resist planarization data to predict the optimum resist and ARC thickness.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
James A. Bruce, Michael D. Caterer, Dianne L. Sundling, "Thin-film interference effects for thin resist films on a broadband scanner", Proc. SPIE 3334, Optical Microlithography XI, (29 June 1998); doi: 10.1117/12.310800; https://doi.org/10.1117/12.310800

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