Manufacturing method of semiconductor device

The embodiment of the invention relates to the technical field of semiconductors, and provides a manufacturing method of a semiconductor device. The manufacturing method of the semiconductor device comprises the following steps: providing a laminated layer comprising a semiconductor substrate, a gate structure and an etching stop layer; forming a plurality of dielectric layers on one side, far away from the semiconductor substrate, of the etching stop layer, and forming a patterned photoresist layer on one side, far away from the semiconductor substrate, of each dielectric layer; taking the patterned photoresist layer as a mask, and carrying out dry etching on the plurality of dielectric layers for multiple times to form an open hole for exposing the etching stop layer; treating the inner wall of the open pore by using oxygen to remove a reaction product formed in the open pore in the process of forming the open pore; and performing dry etching on the etching stop layer in the open hole to form the loss of th