Semi-automatic wafer examination procedure for non-destructive control of spray coating processes

During the development of resist materials for lithographic application and their respective coating methods, numerous batches of samples have to be characterized in terms of resist thickness and edge coverage within a short timeframe. In order to prevent damage to the samples for further processing, the characterization method has to be non-destructive. This demand prohibits microscopic inspection of breaking edges, a common practice for inspection of small-scale series. In this paper, a semi-automated examination procedure for spray coating processes based on stylus profilometer are presented. Utilizing a specific test pattern on the wafer ensures both, reproducibility and batch-wise processing. Profilometric raw data are processed with minimal user interaction, using a specifically designed software script based on the open-source software package ‘R’ (2016). Evaluation of matched profiles can be done using any data visualization software. The presented method is used for the design and optimization of a custom made spray coating equipment as well as the development of a suitable negative resist.