Predicting Performance of Dry Film Photoresist by Analysis of the Resist Sidewall

With the vast quantities of dry film resist utilised for imaging, strict controls on all relevant parameters are necessary to ensure compatibility of resist and process chemistry. The printing operation has as its goal the production of a well‐defined mould. The resist sidewall forms the side of this mould and, as such, determines printing accuracy, its quality predicting ultimate performance. Scanning Electron Microscope photographs of the sidewall can evaluate various parameters. The analysis investigates sidewall shape and definition and the variables that affect them, i.e., contact intimacy, under and overexposure, light collimation, developing pressure, delay time and solvent composition. Defective conditions such as foot deterioration leading to resist lifting also receive scrutiny under this process monitoring analysis technique.