1 January 1988 Characterization Of A Submicron Image Reversal Process
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The complete characterization of a resist imaging process is critical to it's success in a production environment. AZ-5214 resist in image reversal mode offers a single layer process that appears to be viable for submicron processing. It does, however exhibit some unique problems that had to be solved during process development. These are: 1) an extreme sensitivity to processing delays, 2) undercut profiles on reflective metal surfaces and 3) different dry etch characteristics. In this development effort the key advantages of image reversal were: reduced proximity effects, higher resolution, vertical resist profiles, as well as greater exposure latitude. AZ-5214 used in image reversal mode is very sensitive to any change in delay time during the processing sequence. In each case increased delay time causes growth in linewidth. This change in dimension is most significant right after the exposure and bake steps. The problem can be minimized by employing a stabilization time after softbake and exposure. Integrating the reversal bake, flood expose, and develop sequence in a single track is also necessary for consistent dimensional control. Negative tone processing of AZ-5214 resist exhibits undercut profiles at the resist metal interface. Metals with different reflectivity such as aluminum, moly, and Ti/W all demonstrate this problem. The use of anti-reflection layers provide vertical profiles at the expense of increased process complexity. Layers that have shown good results are PE/CVD nitride and PE/CVD oxide. The process characterization data includes: exposure and focus latitude for a range of feature sizes, proximity effect data for dense and isolated features, linewidth uniformity after etch, and dwell time latitude. Also included are the results of daily particle counts over a four month period.
© (1988) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
E. W. Balch, E. W. Balch, S. E. Weaver, S. E. Weaver, R. J. Saia, R. J. Saia, } "Characterization Of A Submicron Image Reversal Process", Proc. SPIE 0922, Optical/Laser Microlithography, (1 January 1988); doi: 10.1117/12.968436; https://doi.org/10.1117/12.968436

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