Registration mark formation during sidewall image transfer process

• Main Authors: Conklin, David J, Lie, Fee Li, Gabor, Allen H, Kim, Byeong Y, Kanakasabapathy, Sivananda K, Sieg, Stuart A
• Format: Patent
• Language: English
• Published: 07.08.2018
• Subjects: APPARATUS SPECIALLY ADAPTED THEREFOR; BASIC ELECTRIC ELEMENTS; CINEMATOGRAPHY; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; ELECTROGRAPHY; HOLOGRAPHY; MATERIALS THEREFOR; ORIGINALS THEREFOR; PHOTOGRAPHY; PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES,e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTORDEVICES; PHYSICS; SEMICONDUCTOR DEVICES

Methods of forming a registration mark such as an alignment mark or overlay mark during formation of sub-lithographic structures are provided. Methods may include forming a plurality of mandrels over a hard mask over a semiconductor layer, each mandrel including a spacer adjacent thereto. At least one mandrel is selected of the plurality of mandrels and a mask is formed over the at least one selected mandrel. The plurality of mandrels are removed leaving the spacers, the mask preventing removal of the at least one selected mandrel. The mask is removed. A first etching patterns the sub-lithographic structures and the registration mark into the hard mask using the spacers as a pattern of the sub-lithographic structure and the at least one selected mandrel and adjacent spacer for the registration mark. A second etching forms the sub-lithographic structures in the semiconductor layer using the patterned hard mask and to form the registration mark in the semiconductor layer using the at least one selected mandrel and the patterned hard mask.