Fin cut for tight fin pitch by two different sit hard mask materials on fin
AssigneeInternational Business Machines Corporation
InventorsKangguo Cheng, Ali Khakifirooz, Alexander Reznicek, Tenko Yamashita
Life of this patent
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Abstract
Methods that enable fin cut at very tight pitch are provided. After forming a first set of paired sidewall image transfer (SIT) spacers and a second set of paired SIT spacers composed of different materials, portions of the first set of the paired SIT spacers can be selectively removed without adversely affecting the second set of the paired SIT spacers, even portions of both sets of the paired SIT spacers are exposed by the cut mask due to the different etching characteristics of the different materials.
Claims15
A method of forming a semiconductor structure comprising:
- forming a plurality of mandrel structures on a substrate;
- forming first spacers on sidewalls of the plurality of mandrel structures;
- forming sacrificial spacers on sidewalls of the first spacers;
- forming second spacers on sidewalls of the sacrificial spacers;
- removing the plurality of mandrel structures and the sacrificial spacers selective to the first spacers and the second spacers;
- forming a cut mask including at least one opening therein over the first spacers, the second spacers and exposed surfaces of the substrate, the at least one opening exposing portions of the first spacers and portions of the second spacers;
- removing exposed portions of the first spacers selective to exposed portions of the second spacers;
- removing the cut mask selective to remaining portions of the first spacers and the second spacers;
- forming another cut mask including at least one opening therein over the remaining portions of the first spacers, the second spacers and exposed surfaces of the substrate, the at least one opening exposing portions of the remaining portions of the first spacers and portions of second spacers;
- and
- removing exposed portions of the second spacers selective to exposed portions of the remaining portions of the first spacers.
Dependencies are inferred from the claim text.