Photoresist characterization for lithography simulation: II. Exposure parameter measurements

Clifford L. Henderson; Sanju Pancholi; Sajed A. Chowdhury; C. Grant Willson; Ralph R. Dammel

doi:10.1117/12.275883

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7 July 1997 Photoresist characterization for lithography simulation: II. Exposure parameter measurements

Clifford L. Henderson, Sanju Pancholi, Sajed A. Chowdhury, C. Grant Willson, Ralph R. Dammel

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Proceedings Volume 3049, Advances in Resist Technology and Processing XIV; (1997) https://doi.org/10.1117/12.275883
Event: Microlithography '97, 1997, Santa Clara, CA, United States

Abstract

Lithography simulation has become an increasingly important tool for the semiconductor industry as attempts are made to extend current lithographic technologies. The usefulness of this simulation capability has been somewhat hindered by the lack of availability of accurate modeling parameters for the various commercial resist systems. In particular, three sets of data are required to model a typical non-chemically amplified photoresist: the refractive index as a function of wavelength and exposure, the exposure or ABC parameters (the Dill parameters), and the development parameters. This work focuses on the accurate extraction of exposure parameters for non-chemically amplified resists. Previous exposure parameter extraction techniques such as those proposed by Dill involve a number of simplifying assumptions including the assumption that the refractive index of the resist does not change during exposure and that the index of the substrate is matched to the resist throughout the exposure process. However, the refractive index of the photoresist does vary during exposure as the chemical composition of the photoresist changes. A rigorous analysis technique for extracting exposure parameters which accounts for this refractive index change and other previously ignored factors has been developed. An apparatus has been constructed to perform bleaching experiments on non- chemically amplified resists and this new, rigorous analysis technique has been used to extract exposure parameters for a series of commercial resists. Some of the results of these studies are presented together with comparisons to previous parameter extraction techniques.

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Clifford L. Henderson, Sanju Pancholi, Sajed A. Chowdhury, C. Grant Willson, and Ralph R. Dammel "Photoresist characterization for lithography simulation: II. Exposure parameter measurements", Proc. SPIE 3049, Advances in Resist Technology and Processing XIV, (7 July 1997); https://doi.org/10.1117/12.275883

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