Semiconductor structure and preparation method thereof, three-dimensional memory and storage system

The invention provides a semiconductor structure and a preparation method thereof, a three-dimensional memory and a storage system, relates to the technical field of semiconductor chips, and aims to improve the manufacturing precision of a plurality of CT holes so as to improve the conductivity of contact parts in the plurality of CT holes. The semiconductor structure includes a stacked structure, a plurality of contact portions, and a dummy fill portion. The stacked structure comprises a plurality of gate layers and a plurality of first dielectric layers which are alternately stacked. The stacked structure has a memory region and a connection region. The plurality of contact parts are arranged in the connection area. And the contact part extends from the upper surface of the stacked structure to a target gate layer in the multiple gate layers and is connected with the target gate layer. The virtual filling part is arranged on one side, far away from the storage area, of the plurality of contact parts, and th