Method for the formation of a protective dual liner for a shallow trench isolation structure

摘要

On a substrate formed of a first semiconductor layer, an insulating layer and a second semiconductor layer, a silicon oxide pad layer and a silicon nitride pad layer are deposited and patterned to define a mask. The mask is used to open a trench through the first semiconductor layer and insulating layer and into the second semiconductor layer. A dual liner of silicon dioxide and silicon nitride is conformally deposited within the trench. The trench is filled with silicon dioxide. A hydrofluoric acid etch removes the silicon nitride pad layer along with a portion of the conformal silicon nitride liner. A hot phosphoric acid etch removes the silicon oxide pad layer, a portion of the silicon oxide filling the trench and a portion of the conformal silicon nitride liner. The dual liner protects against substrate etch through at an edge of the trench between the first and second semiconductor layers.

主权项

1. A method, comprising:
on a substrate formed of a first semiconductor layer over an insulating layer over a second semiconductor layer, depositing a first pad layer formed of a first pad material; depositing a second pad layer formed of a second pad material; patterning the first and second pad layers to define a mask; using said mask to open a trench surrounding an active region, said trench extending through both the first semiconductor layer and the insulating layer and further extending at least partially into the second semiconductor layer; depositing a first conformal liner made of a first liner material in said trench; depositing a second conformal liner made of a second liner material on said first conformal liner in said trench; filling said trench with an insulating material; removing the second pad layer along with a portion of the second conformal liner near a top of the filled trench to form a first divot between the first conformal liner and the insulating material filling said trench; and removing the first pad layer, a portion of the insulating material filling said trench and a portion of the first conformal liner near the top of the filled trench to form a second divot between the second conformal liner and the first semiconductor layer.