Intrench profile

摘要

A method of etching a recess in a semiconductor substrate is described. The method may include forming a dielectric liner layer in a trench of the substrate where the liner layer has a first density. The method may also include depositing a second dielectric layer at least partially in the trench on the liner layer. The second dielectric layer may initially be flowable following the deposition, and have a second density that is less than the first density of the liner. The method may further include exposing the substrate to a dry etchant, where the etchant removes a portion of the first liner layer and the second dielectric layer to form a recess, where the dry etchant includes a fluorine-containing compound and molecular hydrogen, and where the etch rate ratio for removing the first dielectric liner layer to removing the second dielectric layer is about 1:1.2 to about 1:1.

主权项

1. A method of etching a recess in a semiconductor substrate, the method comprising:
forming a dielectric liner layer in a trench of the substrate, wherein the liner layer has a first density; depositing a second dielectric layer at least partially in the trench on the liner layer, wherein the second dielectric layer is initially flowable following the deposition, and wherein the second dielectric layer has a second density that is less than the first density of the liner layer; exposing the substrate to dry etchant, wherein the etchant removes a portion of the first liner layer and the second dielectric layer to form a recess, wherein the dry etchant comprises a fluorine-containing compound and molecular hydrogen, and wherein an etch rate ratio for removing the first dielectric liner layer to removing the second dielectric layer is about 1:1.2 to about 1:1.