Semiconductor structures and fabrication method thereof

A method for fabricating a semiconductor structure, comprising:

• providing a semiconductor substrate;
• forming a plurality of first underlying metal layers and a plurality of second underlying metal layers in the semiconductor substrate;
• forming an initial metal layer;
• simultaneously forming a plurality of discrete first metal layers and openings by etching the initial metal layer;
• forming a plurality of sidewalls covering the side surface of the plurality of first metal layers;
• and
• forming a plurality of second metal layers to fill the openings, wherein the plurality of first metal layers contact the plurality of first underlying metal layers and the plurality of second metal layers contact the plurality of second underlying metal layers.