Semiconductor structure and forming method thereof

The invention provides a semiconductor structure and a forming method thereof, and the semiconductor structure comprises a semiconductor substrate which comprises a first region and a fourth region; a gate structure which is positioned on the semiconductor substrate in the first region and the fourth region; a barrier layer which is located on the gate structure of the first region, wherein the barrier layer comprises a plurality of grooves penetrating through the barrier layer; a dielectric layer which is located on the semiconductor substrate and the gate structure and fills the groove, wherein the upper surface of the dielectric layer is flush with the upper surface of the barrier layer. The barrier layer and the dielectric layer in the groove are divided into a plurality of parts, and the size of each part is reduced, so the dielectric layer is not easy to sink when being planarized by adopting a chemical mechanical polishing process, and the performance of the device can be improved. 本申请提供半导体结构及其形成方法，所述半