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Proceedings Paper

Formation and verification of a 90-nm contact lumped model
Author(s): Chi-Yuan Hung; Bin Zhang; Yong Done Wang
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Paper Abstract

As IC design rules shrink dramatically while the wavelength reduction in exposure systems can not keep up, extensive usage of Litho RET, Etch trimming and OPC techniques has become common practice in the integrated patterning flow. We examined a large number of CD measurement datasets of 90nm Contact layer ADI and AEI CD. As the etch bias is not a constant through pitch, AEI contribution has to be incorporated in the OPC model. Based on these datasets, we tried to develop a non-constant AEI model. In this paper, we investigated various strategies to streamline OPC modeling. Multiple regression method is used to fit CTR and CTE models. It was revealed that an extra long range Loading Kernel, additional to a well-fitted ADI model, may not successfully meet the fitting criteria we want. Mainly due to the fact that models with too many eigenvectors would have a tendency to over-fit-and-correct CD curves. We introduced an alternative approach by limiting the number of parameters in our model OPC algorithm. We achieved a 90nm Contact Model with OPC empirical data fitting error within +-2nm. Lastly, the wafer verification datasets showed only 3σ = 7.82 nm of through-pitch OPC residual error by using this Constant Threshold Etch Model, compared to simulation residue error 3σ of 8 nm.

Paper Details

Date Published: 6 December 2004
PDF: 7 pages
Proc. SPIE 5567, 24th Annual BACUS Symposium on Photomask Technology, (6 December 2004); doi: 10.1117/12.569308
Show Author Affiliations
Chi-Yuan Hung, Semiconductor Manufacturing International Corp. (China)
Bin Zhang, Semiconductor Manufacturing International Corp. (China)
Yong Done Wang, Synopsys, Inc. (China)


Published in SPIE Proceedings Vol. 5567:
24th Annual BACUS Symposium on Photomask Technology
Wolfgang Staud; J. Tracy Weed, Editor(s)

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