Semiconductor structure and method for manufacturing the same

A semiconductor structure, comprising:

• a plurality of nanostructures formed over a substrate;
• a gate structure formed over the nanostructures;
• a mask layer formed on the gate structure;
• an source/drain (S/D) structure formed adjacent to the gate structure;
• a first dielectric layer disposed over the S/D structure;
• an S/D contact structure extending through the first dielectric layer, wherein the S/D contact structure is through the first dielectric layer,
• a metal silicide layer between the S/D structure and the S/D contact structure, wherein an electrical conductivity of the metal silicide layer is between an electrical conductivity of the S/D structure and an electrical conductivity of the S/D contact structure, wherein the electrical conductivity of the S/D contact structure is greater than the electrical conductivity of the S/D structure;
• and
• a conductive via formed on the S/D contact structure, wherein a portion of the conductive via is formed on a top surface of the mask layer.

A method for manufacturing a semiconductor structure, comprising:

• forming a gate structure over a plurality of nanostructures;
• forming a source/drain (S/D) structure adjacent to the gate structure;
• forming a mask layer over the gate structure;
• forming a first dielectric layer over the mask layer;
• forming a S/D contact structure through the first dielectric layer;
• removing a portion of the S/D contact structure and a portion of the first dielectric layer to expose the mask layer;
• forming a second dielectric layer over the S/D contact structure and the mask layer;
• and
• forming a conductive via through the second dielectric layer, wherein a dielectric constant of the mask layer is greater than a dielectric constant of the second dielectric layer.