A semiconductor structure includes a substrate, a first insulating layer, a second insulating layer, a first seal ring structure, a second seal ring structure, and a passivation layer. The substrate has a chip region and a seal ring region. The first insulating layer is on the substrate. The second insulating layer is on the first insulating layer. The first seal ring structure is in the seal ring region and embedded in the first insulating layer and the second insulating layer, wherein the first seal ring structure includes a stack of metal layers. The second seal ring structure is in the seal ring region and embedded in the first insulating layer, wherein the second seal ring structure includes a polysilicon ring structure. The passivation layer is on the second insulating layer and the first seal ring structure.