Semiconductor structure and forming method thereof

The invention provides a semiconductor structure and a forming method thereof, and the semiconductor structure comprises a bonding wafer, the bonding wafer comprises a device region, the bonding wafer comprises a first wafer and a second wafer which are bonded with each other, the first wafer comprises a first surface and a second surface which are opposite, the second wafer comprises a third surface and a fourth surface which are opposite, and the third surface and the fourth surface are opposite. The fourth surface is bonded with the second surface; a mark opening located in the device region, wherein the mark opening is recessed from the first surface to the second surface; on the premise that the semiconductor structure is not affected, the device area can be accurately positioned through the marking opening, so that the bonding condition of the bonded wafer in the device area is analyzed, the bonding reject ratio analysis and solving efficiency of the bonded wafer can be improved, the resource utilizatio