Integrated circuit and method for forming the same

A method of manufacturing a semiconductor device, comprising:

• forming a stack structure, the stack structure comprising alternating source and drain layers above a substrate;
• etching the stack structure to form a trench;
• forming a first dielectric spacer lining a sidewall surface of the trench;
• forming a backside via in the trench;
• forming a gate structure extending across the first dielectric spacer and the backside via;
• after forming the gate structure, removing an interior portion of the first dielectric spacer not covered by the gate structure to form a first recess;
• and
• filling the first recess with a first conductive material to increase a width of the backside via.

A method of manufacturing a semiconductor device, comprising:

• forming a first epitaxial stack of alternating first semiconductor layers and second semiconductor layers over a front-side surface of a substrate;
• forming a second epitaxial stack of alternating first semiconductor layers and second semiconductor layers over the front-side surface of the substrate;
• forming a first dielectric spacer alongside a sidewall of the first and second epitaxial stacks;
• filling a space between the sidewalls of the first and second epitaxial stacks with a sacrificial dielectric layer wherein the first dielectric spacers comprise a first material and the sacrificial dielectric layer comprises a second material;
• performing a CMP process to a backside of the substrate until a bottom surface of the sacrificial dielectric layer is exposed;
• removing the sacrificial dielectric layer to form a recess;
• and
• filling the recess with a conductive material to form a backside via.