SPACER FORMATION

摘要

Embodiments of the present invention pertain to methods of forming more symmetric spacers which may be used for self-aligned multi-patterning processes. A conformal spacer layer of spacer material is formed over mandrels patterned near the optical resolution of a photolithography system using a high-resolution photomask. A carbon-containing layer is further formed over the conformal spacer layer. The carbon-containing layer is anisotropically etched to expose the high points of the conformal spacer layer while retaining carbon side panels. The conformal spacer layer may then be etched to form spacers without the traditional skewing of the profile towards one side or the other.

主权项

1. A method of forming spacers on a substrate, the method comprising:
forming a layer of mandrel material on the substrate; patterning the layer of mandrel material using a lithography process to form a plurality of mandrels distributed according to a first linear density, wherein an interstice is formed between two adjacent mandrels of the plurality of mandrels; forming a conformal layer of spacer material over the plurality of mandrels, wherein the spacer material comprises silicon; forming a carbon-containing conformal layer over the conformal layer of spacer material; anisotropically etching the carbon-containing conformal layer to expose the portion of the conformal layer of spacer material located above each of the plurality of mandrels and leaving carbon-containing side panels to each side of each of the plurality of mandrels; etching the conformal layer of spacer material to expose the tops of each of the plurality of mandrels and to form spacers, wherein the spacers are distributed according to a second linear density and the second linear density is twice the first linear density; removing the carbon-containing side panels; and removing the plurality of mandrels.