Semiconductor element and manufacturing method thereof

The invention discloses a semiconductor element and a manufacturing method thereof. The semiconductor element comprises a source electrode structure; the first dielectric layer is located on the source electrode structure; the drain electrode structure is located on the first dielectric layer; the second dielectric layer is located on the drain electrode structure; and the channel structure passes through the second dielectric layer, the drain electrode structure and the first dielectric layer and extends to the upper part of the source electrode structure. And the gate structure is located on the second dielectric layer and covers the channel structure. The channel structure comprises a grid core; a channel layer along sidewalls and a bottom surface of the gate core; and the gate dielectric layer is arranged between the channel layer and the gate core, and the gate core, the gate dielectric layer and the end part of the channel layer are in direct contact with the gate structure and are not exposed in the su