Semiconductor structure and fabrication method thereof

A method for fabricating a semiconductor structure, comprising:

• providing a semiconductor substrate having at least a first region;
• forming a dielectric structure over the semiconductor substrate, wherein the dielectric structure includes a first dielectric layer formed over the semiconductor substrate, a first stop layer formed on the first dielectric layer, and a second dielectric layer formed on the first stop layer;
• forming a plurality of first openings in the dielectric structure in the first region by removing portions of the dielectric structure in the first region, wherein forming the plurality of first openings in the dielectric structure comprises:
• forming a first mask layer having a plurality of first mask openings in the first region on a top surface of the second dielectric layer;
• and
• etching the second dielectric layer until a top surface of the first stop layer is exposed using the first mask layer as an etching mask;
• forming a first barrier member in each of the plurality of first openings;
• forming second openings with sidewall surfaces exposing sidewall surfaces of the first barrier members by removing portions of the dielectric structure between adjacent first openings, wherein the semiconductor substrate further includes a second region and the first mask layer in the second region also includes a plurality of second mask openings, further comprising:
• forming second interconnect openings in the second dielectric layer in the second region by etching the second dielectric layer using the first mask layer in the second region as an etching mask,
• wherein a size of the interconnect opening along the direction parallel to the surface of the semiconductor substrate is smaller than approximately 200 μm;
• and
• forming a second barrier member in each of the second openings.