Semiconductor structure and forming method thereof

The invention discloses a semiconductor structure and a forming method thereof, and the structure comprises a substrate which comprises a first region, a second region, and an isolation region located between the first region and the second region; the first fin part is located on the first region, the second fin part is located on the second region, and the third fin part is located on the isolation region; the gate structure stretches across the first fin part, the second fin part and the third fin part and comprises a first work function layer located on the first region and a part of the isolation region and a second work function layer located on the second region and a part of the isolation region; and the contact interface of the first work function layer and the second work function layer is located on the top surface of the third fin part. The third fin portion located on the isolation region can play a blocking role between the first work function layer and the second work function layer, and the pe