Semiconductor structure and manufacturing method thereof

Abstract

Embodiments of the present disclosure provide a semiconductor structure and a manufacturing method thereof, which relate to the field of semiconductors. The method includes: providing a base; forming a plurality of first trenches extending along a first direction in the base, the first trenches forming the base into semiconductor layers arranged at intervals, and filling the first trenches with a first isolation layer; forming a plurality of second trenches extending along a second direction in the semiconductor layers and the first isolation layer, to form the semiconductor layers into a plurality of separate semiconductor pillars and initial bit lines located below the semiconductor pillars; forming third trenches parallel to the first trenches at positions lower than the second trenches; and filling the second trenches and the third trenches with a second isolation layer, where a part of the second isolation layer in the third trenches has gaps.