The present disclosure provides a method of manufacturing a semiconductor structure and a semiconductor structure. The method of manufacturing a semiconductor structure includes: providing a base, wherein the base includes an active region and a shallow trench isolation structure separating the active region, a word line trench is formed in the base, and the word line trench exposes a part of the active region and the shallow trench isolation structure; forming a first intermediate structure in the word line trenches, wherein the first intermediate structure covers side walls and a bottom wall of the word line trench, a first trench is formed in the first intermediate structure, the first intermediate structure includes a sacrificial structure, and the sacrificial structure includes a horizontal portion; and removing the horizontal portion of the sacrificial structure, and closing the first trench, and forming an air chamber.