Fabrication method of semiconductor structure

A fabrication method of a semiconductor structure, comprising:

• providing a substrate;
• forming a plurality of fin structures on the substrate, wherein:
• the plurality of fin structures is arranged parallelly along a first direction, and isolation grooves are formed between adjacent fin structures of the plurality of fin structures;
• and
• each of the plurality of fin structures includes a plurality of sacrificial layers stacked along a normal direction of a surface of the substrate, and a channel layer between every two adjacent sacrificial layers of the plurality of sacrificial layers;
• forming a first isolation layer in each isolation groove;
• forming a second isolation layer on each first isolation layer to fill up a corresponding isolation groove;
• forming a dummy gate structure and removing first isolation layers after forming the dummy gate structure;
• removing the dummy gate structure to form a gate opening at ends of the plurality of sacrificial layers along a second direction perpendicular to the first direction;
• removing the plurality of sacrificial layers to form gate grooves between adjacent channel layers;
• and
• forming a gate structure in the gate opening and the gate grooves, wherein the gate structure surrounds the channel layers.