| CPC H10B 12/488 (2023.02) [H01L 21/31111 (2013.01); H01L 23/528 (2013.01); H10B 12/05 (2023.02); H10B 12/053 (2023.02)] | 14 Claims |
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1. A method of manufacturing a semiconductor structure, comprising:
providing a substrate, the substrate comprising active regions spaced arranged from each other and an isolation structure located between the active regions;
patterning the active regions and the isolation structure to form a word line trench, the word line trench extending along a first direction, and sidewalls of the word line trench exposing the active regions and the isolation structure;
performing corner rounding at least once on the active regions and the isolation structure exposed by the sidewalls of the word line trench, such that a first height difference is formed between remaining active regions and the isolation structure in a second direction, wherein the second direction is parallel to the substrate and perpendicular to the first direction, and the corner rounding comprises:
etching the isolation structure exposed by the sidewalls of the word line trench, such that a first thickness of the active regions are exposed by the isolation structure in the second direction;
performing oxidation on surfaces of the exposed active regions to convert a second thickness of active regions into oxide layers, the oxide layers each having stepped orthographic projection on a surface of the substrate; and
removing the oxide layers; and
after forming the first height difference, forming a word line which filling the word line trench.
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