Buried bit line structure, manufacturing method thereof, and semiconductor structure

A method of manufacturing a buried bit line structure, comprising:

• providing an initial structure, the initial structure comprising a base and a protective layer provided on the base, and the base comprising active region structures and a dielectric layer, and a top surface of the active region structures is flush with a top surface of the dielectric layer;
• forming an initial bit line trench in the initial structure, the initial bit line trench exposing the active region structures;
• forming a conductive structure, the conductive structure being located at a bottom of the initial bit line trench and being at a preset distance from a bottom surface of the initial bit line trench;
• forming a bit line contact structure, the bit line contact structure covering the conductive structure, and a top surface of the bit line contact structure being lower than the top surface of the active region structures;
• and
• forming an insulation structure, the insulation structure covering the bit line contact structure, and a top surface of the insulation structure being flush with a top surface of the protective layer.