Predicting resist sensitivity to chemical flare effects though use of exposure density gradient method

Chemical flare has been shown to be a process limiter for patterns that are surrounded by areas of unexposed resist for certain chemically amplified resists. Using a pattern known to be susceptible to chemical flare effect a method was developed and tested on several materials. Details of the testing patterns, consisting of placements of small and large pattern density areas set to provide multiple degrees of resist loading; and a second level of loading variation achieved by selective exposure locations of those patterns across the wafer are given. Descriptions of the determination of slopes from linear trend-lines of the critical dimensions responses can be used to provide a gauge for internal evaluations as well as feedback to the vendors for chemical flare sensitivity.