Patent ID: 11915940
Assignee: APPLIED MATERIALS, INC.
Field: Semiconductors (Electrical engineering)
Classification: CPC H  C | IPC C  H

Claim 0:
1. A method of cyclic etching, comprising:
(A) depositing, prior to cyclically etching a substrate through a mask opening, a pre-etch protection layer conformally over the mask, sidewalls of the mask defining the mask opening; and an exposed portion of the substrate exposed through the mask opening, the pre-etch protection layer deposited to a first thickness; and
(B) cyclically etching the substrate by:
(i) depositing a protection layer in the opening of the mask, the protection layer deposited to a second thickness that is less than half of the first thickness;
(ii) etching through a portion of the protection layer disposed on the substrate and etching the substrate wherein the etching comprises exposing the substrate for a first period of time to a plasma formed from a fluorine containing gas and oxygen in presence of a bias power applied to the substrate, and exposing the substrate for a second period of time to a plasma formed essentially from the fluorine contaning gas, wherein the bias power applied during the first period of time is greater than bias power applied during the second period of time; and
(iii) repeating (i) and (ii) until an end point is reached.