Three-dimensional semiconductor structure and formation method thereof

A three-dimensional semiconductor structure, comprising:

• a substrate;
• and
• a device structure positioned on a top surface of the substrate;
• wherein the device structure comprises memory rows arranged at intervals along a first direction, each of the memory rows comprises memory cells arranged at intervals along a second direction and a gap between adjacent two of the memory cells, each of the memory cells comprises a first stacked layer and a word line structure, the word line structure comprises a first part positioned in the first stacked layer and a second part extending out of the first stacked layer along the first direction, at least adjacent two of the memory rows exist, the second part of the memory cell in one of the memory rows extends into the gap in another one of the memory rows, both the first direction and the second direction are directions parallel to the top surface of the substrate, and the first direction intersects with the second direction.