Various embodiments provide double patterning methods and structures. In an exemplary method, a to-be-etched layer can be provided. A stress layer can be formed on the to-be-etched layer. The stress layer can have a tensile stress. A plurality of discrete sacrificial layers can be formed on the stress layer. A sidewall-spacer material layer covering the plurality of sacrificial layers and the stress layer can be formed. The sidewall-spacer material layer can be etched to form a sidewall spacer on a sidewall of each sacrificial layer of the plurality of sacrificial layers. The stress layer at each side of the each sacrificial layer can be etched to form a groove passing through a thickness of the stress layer. The plurality of sacrificial layers can be removed.