High-throughput contact critical dimension and gray level value measurement

Abstract

A high-throughput e-beam monitoring system, eProfile®, is designed to quickly measure gray level value (GLV) and critical dimension (CD) of the structures of interest on product wafers. Two wafers are used in this study, one wafer is at after etch inspection (AEI) with contact mask focus exposure matrix (FEM), and another is normal exposure contact AEI wafer. High-throughput CD measurement of AEI wafer at holes with different patterns, such as semi-dense and SRAM array were measured with results matched the FEM expectation very well. The system is also be used to measure GLV of the SEM images on contact holes of a normal production wafer to reflected the under etch (high GLV) problem in a semi-dense hole pattern.