Method of anisotropic extraction of silicon nitride mandrel for fabrication of self-aligned block structures

• Main Authors: SHERPA, SONAM, RANJAN, ALOK
• Format: Patent
• Language: Chinese; English
• Published: 21.11.2021
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

A method of preparing a self-aligned block (SAB) structure is described. The method includes providing a substrate having raised features defined by a first material containing silicon nitride and a second material containing silicon oxide formed on side walls of the first material, and a third material containing an organic material covering some of the raised features and exposing some raised features according to a block pattern formed in the third material. The method further includes forming a first chemical mixture by plasma-excitation of a first process gas, and exposing the first material on the substrate to the first chemical mixture. Thereafter, the method includes forming a second chemical mixture by plasma-excitation of a second process gas, and exposing the first material on the substrate to the second plasma-excited process gas to selectively etch the first material relative to the second and third material.