Semiconductor device

In the semiconductor device, a bit line structure and node contact structures are located in a storage area of a substrate, the node contact structures are arranged on two sides of the bit line structure, a gate structure and contact plugs are located in a peripheral circuit area of the substrate, and the contact plugs are arranged on two sides of the gate structure. The isolation layer covers the top of the bit line structure, the top of the gate structure, the top of the node contact structure and the top of the contact plug so as to electrically isolate the adjacent node contact structure and the adjacent contact plug. When the isolation layer of the peripheral circuit region is subsequently etched to form the groove exposing the contact plug, the groove is more easily aligned with the contact plug under the condition of not changing the etching method, so that the conductive plug formed in the groove does not deviate from the contact plug, the process window is widened, the performance and reliability of