Claritas TM — A unique and robust endpoint technology for silicon drie processes with open area down to 0.05%

Endpoint detection (EPD) is a critical control functionality for many etch processes, especially for deep silicon etches [1] that terminate on an underlayer. Where this device structure is employed, it is vital that the point at which the etch process reaches the underlayer is detected as promptly as possible. This allows for proper management of the overetch to clear all features to the underlayer without running for longer than necessary and introducing lateral notching to the base of the feature [2]. As device requirements have become more stringent, lower open areas and higher aspect ratios have necessitated development of more sensitive techniques to achieve successful endpoint detection and overetch control.