1 May 1994 Metrology sensors for advanced resists
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We have initiated an effort to develop metrology tools that isolate the effect of each process step. Light scattered from diffracting structures is analyzed to determine characteristics of the structure. The technique is rapid, non-destructive, and extremely sensitive to variations in the samples that were examined. Through our technical collaboration with Texas Instruments Inc. we obtained wafers coated with surface imaging resists and exposed under varying focus and exposure conditions. We present results that utilize scatterometry to monitor the exposure step to determine defocus and exposure variations in the latent image. We also report using scatterometry to monitor the post-exposure bake (PEB) process for chemically amplified resists. Wafer-to-wafer variations in resist and underlying film thicknesses result in CD variations for constant exposure. The PEB time can be adjusted for each wafer to account for some of the parameter variations. We present experimental data supporting the concept of a scatterometer PEB monitor.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Shoaib H. Zaidi, Shoaib H. Zaidi, Steven L. Prins, Steven L. Prins, John Robert McNeil, John Robert McNeil, S. Sohail H. Naqvi, S. Sohail H. Naqvi, } "Metrology sensors for advanced resists", Proc. SPIE 2196, Integrated Circuit Metrology, Inspection, and Process Control VIII, (1 May 1994); doi: 10.1117/12.174159; https://doi.org/10.1117/12.174159

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