Patent ID: 11239088

Abstract:
Semiconductor device and fabrication method are provided. A plurality of first-type fin groups and second-type fins, each between the first-type fin groups, are formed on a substrate. A first-type fin group includes first-type fins. The first-type fins and the second-type fins are arranged in a direction perpendicular to an extending direction of the first-type fins and the second-type fins. The second-type fins are removed to form first trenches between corresponding first-type fin groups. A protective layer is formed on sidewalls of the first trenches after removing the second-type fins. The protective layer covers sidewalls of the first-type fins that are perpendicular to a width direction of the first-type fins. Second trenches are formed in the substrate under the first trenches by etching the substrate at bottoms of the first trenches using the protective layer as an etch mask.