Dynamical mapping and end-point detection of photoresist development by using plastic-fiber-bundle probe array

A multiport plastic-optical-fiber-bundle-based (POFB-based) metrology for dynamic monitoring of the endpoint and variation on thickness or dissolving rate of photoresist film during development is demonstrated. Experimentally, the dissolution process of the AZ1350 photoresist film at several different sites on a 150-mm (6-in) silicon wafer was dynamically monitored. The dissolving rate can be simultaneously estimated from the time-resolved optical interference reflected from the sample surface. The deviation on the thickness of PR film estimated by using the current apparatus is in good agreement with that observed by ellipsometry. The error in measurements is less than 1%, Furthermore, a two-dimensional contour mapping of the thickness of PR film on silicon wafer has been demonstrated by using 36 POFB probes.