Carbon-based deposits used for Critical Dimension (CD) control during high aspect ratio feature etch and to form protective layers

摘要

A semiconductor substrate is fabricated by (a) vertically etching a feature having a depth into one or more layers and sidewalls formed on the semiconductor substrate, and (b) depositing an amorphous carbon liner onto the sidewalls of the feature. Step (a) and optionally step (b) are repeated until the vertical etch feature reaches a desired depth. With each iteration of step (a), the depth of the feature is vertically etched deeper into one or more layers, while the amorphous carbon liner resists lateral etching of the sidewalls of the features. With each selectable iteration of step (b), the amorphous carbon liner deposited on the sidewalls of the feature is replenished.