Method for Removing a Dielectric Layer from a Bottom of a Trench
AssigneeInfineon Technologies AG
InventorsLothar Brencher, Carsten Moritz
Life of this patent
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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.
Claims13
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 comprising:
- providing a substrate, wherein the trench is formed in the substrate, and wherein the bottom of the trench and the sidewalls of the trench are covered with the dielectric layer;
- 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 conditions of a plasma etch process to a first mode;
- and
- 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.
A method for removing a dielectric layer from a bottom of a trench formed in a substrate while maintaining the dielectric layer on sidewalls of the trench and on a surface of the substrate by use of a plasma etch process using CxFy and O2, the method comprising the steps of:
- providing the substrate, wherein the trench is formed in the substrate, and wherein the bottom of the trench and the sidewalls of the trench are covered with the dielectric layer;
- 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 and the surface of the substrate by adjusting a ratio between CxFy and O2 to a first mode, wherein CxFy is one out of C5F8, C4F6 and C3F8;
- etching the dielectric layer at the bottom of the trench and etching the passivation layer at the upper portion of the trench and the surface of the substrate by adjusting the ratio between CxFy and O2 to a second mode;
- and
- repeatedly changing between the modes until the dielectric layer at the bottom of the trench is completely removed.
Dependencies are inferred from the claim text.