Abstract: Provided are a semiconductor structure and a forming method thereof, and a photomask layout. One form of a semiconductor structure includes: a base, including a substrate and a plurality of fins arranged in parallel on the substrate, the substrate including a transistor cell area, and in the transistor cell area, in a direction perpendicular to an extending direction of the fin, the fin closest to a boundary of the transistor cell area being used as an edge fin, and the edge fin having an outer side wall facing the boundary of the transistor cell area; and a gate structure, spanning the fin and covering a part of a top and a part of a side wall of the fin, and the gate structure exposing at least a part of an outer side wall of any of the edge fins.