Semiconductor structure and forming method therefor

A semiconductor structure, comprising:

• a base;
• a gate structure located on the base;
• a source/drain doped area located in the base on two sides of the gate structure;
• a source/drain interconnect layer located on a top of the source/drain doped area and contacting the source/drain doped area;
• a gate plug located on a top of the gate structure and contacting the gate structure;
• a source/drain plug located on a top of the source/drain interconnect layer and contacting the source/drain interconnect layer;
• a dielectric layer, covering side walls of the gate plug and the source/drain plug and filling between the gate plug and the source/drain plug;
• a first gap located between the side wall of the gate plug and the dielectric layer and between the side wall of the source/drain plug and the dielectric layer, wherein the first gap being is laterally bounded by the dielectric layer, and the first gap located between the side wall of the source/drain plug and the dielectric layer is isolated from the gate structure by the dielectric layer;
• and
• a sealing layer located on the dielectric layer and sealing the first gap, a first portion of the first gap located on the side wall of the source/drain plug or a second portion of the first gap located on the side wall of the gate plug and the sealing layer forming a first air gap.