Semiconductor structure and preparation method thereof

The invention relates to a semiconductor structure and a preparation method thereof. The preparation method of the semiconductor structure comprises the following steps: providing a substrate; a plurality of conductive structures distributed at intervals are formed on the substrate. Forming a retaining wall covering the side wall of the conductive structure on the substrate, including forming a vertical side wall on the side wall of the conductive structure; l-shaped side walls are formed on the side walls of the vertical side walls, and the corners of the adjacent L-shaped side walls are opposite. And forming an interlayer dielectric layer covering the conductive structure and the retaining walls and filling gaps between the adjacent retaining walls. The semiconductor structure and the preparation method thereof can reduce or eliminate the adverse effect of filling holes in the interlayer dielectric layer, thereby improving the filling quality of the interlayer dielectric layer, and further improving the per