Patent ID: 6960510
Filing Date: 2005-11-01
Classification: H01L

Abstract:
1. A method of forming a structure having sub-lithographic dimensions, comprising the steps of: (a) forming a first hard mask layer on a substrate, said first hard mask layer comprising an upper layer and a lower layer, said lower layer of the first hard mask layer being in direct mechanical contact with the substrate; (b) forming a mandrel on the upper layer of first hard mask layer, said mandrel having a vertical sidewall, a top surface and a chamfered corner forming an angled surface, said angled surface being disposed between said vertical sidewall and said top surface a second edge of the angled surface being opposite a first edge of the angled surface; (c) forming a second hard mask layer over said chamfered mandrel and portions of said first hard mask layer not covered by said chamfered mandrel; (d) performing an angled ion implantation into said second hard mask layer to form an implanted region in said second hard mask layer and an implanted region in said second hard mask layer, said unimplanted region in said second hard mask layer substantially free of ions implanted by the angled ion implantation; (e) totally removing said implanted region in said second hard mask layer; (f) removing a portion of said unimplanted region and removing a portion of said mandrel exposed by step (c), to totally remove the chamfered corner thereby leaving a newly exposed top surface of the mandrel coplanar with a newly exposed surface of the unimplanted region, wherein step (f) leaves a remaining portion of the the unimplanted region consisting of a mutually perpendicular first and second portion, said first portion having a first surface in direct mechanical contact with the upper layer of the first hard mask layer and oriented parallel to the first mask, said second portion oriented perpendicular to the first hard mask layer; (g) after step (f), totally removing the mandrel, leaving the first surface of the unimplanted region as the only unexposed surface of the unimplanted region; (h) after step (g), removing all portions of the upper layer of the first hard mask layer that are not covered by the unimplanted region; and (i) after step (h), totally removing the unimplanted region and totally removing all portions of the lower layer of the first hard mask layer that is not protected by the upper layer of the first hard mask layer.