Semiconductor structure and manufacturing method thereof

The embodiment of the invention discloses a semiconductor structure and a manufacturing method thereof. The semiconductor structure comprises a substrate, a dielectric layer, a first gate structure and a second gate structure. The substrate comprises discrete semiconductor channels, and the semiconductor channels are arranged on the top of the substrate and extend in the vertical direction. The first gate structure is disposed in the first region of the semiconductor channel and surrounds the semiconductor channel. The second gate structure is arranged in the second region of the semiconductor channel and comprises a ring structure and at least one bridge structure; the ring structure surrounds the semiconductor channel, and the at least one bridge structure penetrates through the semiconductor channel and extends to the inner wall of the ring structure in the penetrating direction. The dielectric layer is located between the first gate structure and the semiconductor channel and between the second gate struc