Perimeter trench formation and delineation etch delayering

Abstract

Apparatus and methods are disclosed for sample preparation, suitable for online or offline use with multilayer samples. Ion beam technology is leveraged to provide rapid, accurate delayering with etch stops at a succession of target layers. In one aspect, a trench is milled around a region of interest (ROI), and a conductive coating is developed on an inner sidewall. Thereby, reliable conducting paths are formed between intermediate layers within the ROI and a base layer, and stray current paths extending outside the ROI are eliminated, providing better quality etch progress monitoring, during subsequent etching, from body or scattered currents. Ion beam assisted gas etching provides rapid delayering with etch stops at target polysilicon layers. Uniform etching at deep layers can be achieved. Variations and results are disclosed.

Dependencies are inferred from the claim text.