Photoresist polymer coatings in the film-substratum systems usually generate selfinduced residual stress during processing. It is believed that the residual stress is the driving force for buckling, cracking and delamination of the polymer coatings. Analysis of the residual stress development during processing is of great interest and practical importance.
Holographic interferometry technique has been developed for the direct measurements of general 2-dimensional stresses in thin films.[l] It turns out that it is a powerful technique to analyze residual stress development in polymer coatings during processing. By directly measuring the residual stress for each processing stage, the history of residual stress evolution can be closely followed and the residual stresses generated from different origins can be separated. By varying UV curing dosage, thermal curing temperature and the sequence of thermal and UV curing procedures, different residual stresses from various processing conditions can be comprehensively analyzed. Combining these data with mechanical properties of the coating offers valuable information for better understanding of the processing mechanism and enables one to optimize processing conditions for the best product capability.