An Improved Fiber-Bundle-Coupler Array for End-Point Detection Process

Abstract

We demonstrated a new-designed plastic-optical-fiber-bundle (POFB) coupler array for dynamic monitoring and end-point detection of the photoresist development process. A better optical collecting efficiency is achieved by using a normal illumination/detection scheme and a POFB coupler with larger cross section. Time-resolved dissolution rate can be obtained by synchronous calculation of the reflected optical interference data with deviation of less than 1.5%. Experiment on in-situ mapping of transient thickness variation of photoresist film during development by using two-dimensional POFB coupler array is also reported. The POFB-based coupler exhibits relatively low coupling and insertion loss at visible light wavelength as compared with the silica-fiber-based one. The system is compatible for real-time/multi-port measurements of micro-lithographic and dielectric etching processes.