Using a site services development spray monitor (DSM 100) and a post processing algorithm, the in-situ measured development rates of photoresist were obtained. The interference signals for eight different wavelengths were simultaneously monitored on a patterned wafer as it spun on the development module of a wafer track. Since the interference signal is generated from a circularly polarized light source, the DSM 100 has demonstrated robustness to the red cloud effect, developer spray, bubbles in the developer, and ambient light. After collecting the eight interference curves, these post processing algorithms used the Marquardt Levenberg non- linear regression algorithm and a linear regression approach to find the development rate as a function of development time. The first approach generated the better curve. A plot of development rate versus depth was generated via numerical integration of the plot of development rate versus time. This technique is equally well suited for other types of exposure and resist chemistries.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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