Semiconductor structure and forming method thereof

The invention discloses a semiconductor structure and a forming method thereof, and the method comprises the steps: providing a substrate, and forming a channel projection part on the substrate; forming an isolation structure on the substrate at the side part of the channel lug boss, wherein the isolation structure covers the top of the channel lug boss; along the normal direction of the substrate, removing the isolation structure of the first partial thickness in the partial region, forming a gate groove crossing the channel lug boss in the isolation structure, and exposing a part of the top and a part of the side part of the channel lug boss by the gate groove; forming a gate structure crossing the channel lug boss in the gate groove; along the normal direction of the substrate, removing the isolation structure of the second partial thickness at the side part of the gate structure; and after the isolation structure of the second part of thickness at the side part of the gate structure is removed, forming a