Method for removing a dielectric layer from a bottom of a trench

US9082719B2 · kind B2 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Lothar Brencher · Radeberg, DE
• Carsten Moritz · Radeberg, DE

Key dates

• Filing date: Oct 19, 2012
• Grant date: Jul 14, 2015
• Expiry date: Oct 19, 2032

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/76844
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

Embodiments provide a method for removing a dielectric layer from a bottom of a trench while maintaining the dielectric layer on sidewalls of the trench. The method includes etching the dielectric layer at the bottom of the trench and generating a passivation layer on the dielectric layer at an upper portion of the trench by adjusting the conditions of a plasma etch process to a first mode; and a step of etching the dielectric layer at the bottom of the trench and etching the passivation layer at the upper portion of the trench by adjusting the conditions of the plasma etch process to a second mode before the dielectric layer at the bottom of the trench is completely removed.