Single-wafer real-time etch rate and uniformity predictor for plasma etch processes

Abstract

The present disclosure relates to semiconductor manufacturing, in particular to a real-time method for qualifying the etch rate for plasma etch processes. A method for testing a semiconductor plasma etch chamber may include: depositing a film on a substrate of a wafer, the wafer including a center region and an edge region; depositing photoresist on top of the film in a pattern that isolates the center region from the edge region of the wafer; and performing an etch process on the wafer that includes at least three process steps. The three process steps may include: etching the film in any areas without photoresist covering the areas until a first clear endpoint signal is achieved; performing an in-situ ash to remove any photoresist; and etching the film in any areas exposed by the removal of the photoresist until a second clear endpoint is achieved. The method may further include determining whether both endpoints are achieved within respective previously set tolerances, and, if both endpoints are achieved within the previously set tolerance, qualifying the plasma etch chamber as verified.