HDP fill with reduced void formation and spacer damage

摘要

A method for filling gaps between structures includes forming a plurality of high aspect ratio structures adjacent to one another with gaps, forming a first dielectric layer on tops of the structures and conformally depositing a spacer dielectric layer over the structures. The spacer dielectric layer is removed from horizontal surfaces and a protection layer is conformally deposited over the structures. The gaps are filled with a flowable dielectric, which is recessed to a height along sidewalls of the structures by a selective etch process such that the protection layer protects the spacer dielectric layer on sidewalls of the structures. The first dielectric layer and the spacer dielectric layer are exposed above the height using a higher etch resistance than the protection layer to maintain dimensions of the spacer layer dielectric through the etching processes. The gaps are filled by a high density plasma fill.

主权项

1. A method for filling gaps between structures in a semiconductor device, comprising:
forming a plurality of high aspect ratio structures adjacent to one another to provide gaps therebetween; forming a first dielectric layer on tops of the high aspect ratio structures; conformally depositing a spacer dielectric layer over the high aspect ratio structures; removing the spacer dielectric layer from horizontal surfaces; conformally depositing a protection layer over the high aspect ratio structures; filling the gaps with a flowable dielectric; recessing the flowable dielectric to a height along sidewalls of the high aspect ratio structures by a selective etch process such that the protection layer protects the spacer dielectric layer on the sidewalls of the high aspect ratio structures; exposing the first dielectric layer and the spacer dielectric layer by an etch process that selectively removes the protection layer above the height wherein the first dielectric layer and the spacer dielectric layer have a higher etch resistance than the protection layer to maintain dimensions of the spacer layer dielectric through the recessing step and the exposing step; and filling the gaps by a high density plasma fill.