Patent ID: 11915967
Assignee: CHANGXIN MEMORY TECHNOLOGIES, INC.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method for manufacturing a semiconductor device, comprising:
providing a semiconductor substrate, the semiconductor substrate comprising a shallow trench and active areas isolated from the shallow trench;
forming an oxygen-containing layer on exposed outer surfaces of the shallow trench and the active areas;
filling a first sacrificial layer of a set height in the shallow trench comprising the oxygen-containing layer on a surface of the shallow trench, the set height being lower than heights of the active areas;
forming an etch stop layer on an upper surface of the first sacrificial layer;
forming etching holes in an edge region of the semiconductor substrate, the etching holes penetrating through the etch stop layer;
removing the first sacrificial layer below the etch stop layer to form an air gap;
filling an isolation layer on the etch stop layer in the shallow trench to form a shallow trench isolation structure containing the air gap, wherein the etching holes are filled by the isolation layer; and
etching the active areas and the shallow trench isolation structure to form wordline trenches, wherein bottoms of the wordline trenches in the shallow trench isolation structure are higher than the set height.