In-Line Inspection on Thickness of Sputtered Thin Ta and TaN Films by Spectroscopic Ellipsometry

Abstract

An optical method utilizes spectroscopic and ellipsometry(SE) technique is developed to measure thin metal thickness below 300A. Repeated tests have been made on various TaN or Ta films to check the stability. Sheet resistance of the films has been measured by four-point probe to check the correlation. TEM analysis has been made to check the accuracy of the measurement. The results match well with TEM and show good repeatability and reproducibility(R&R) performance for 100A and 200A Ta or TaN film deposited directly on silicon substrate, which indicates the possibility for the process monitor of thin metal films.