Patent ID: 9209076
Filing Date: 2015-12-08
Classification: H01L

Abstract:
1. A method comprising: performing a double patterning process to form a first mandrel, a second mandrel, and a third mandrel parallel to each other, with the third mandrel being between the first mandrel and the second mandrel; etching the third mandrel to cut the third mandrel into a fourth mandrel and a fifth mandrel, with an opening separating the fourth mandrel from the fifth mandrel; forming a spacer layer on sidewalls of the first mandrel, the second mandrel, the fourth mandrel, and the fifth mandrel, wherein the opening is fully filled by the spacer layer; removing horizontal portions of the spacer layer, with vertical portions of the spacer layer remaining un-removed; using the first mandrel, the second mandrel, the fourth mandrel, and the fifth mandrel and the vertical portions of the spacer layer as an etching mask to etch a target layer, with trenches formed in the target layer; and filling the trenches with a filling material.