Fully self-aligned via with selective bilayer dielectric regrowth

A semiconductor device, comprising:

• a plurality of conductive structures formed in a first dielectric layer, top surfaces of the plurality of the conductive structures and a top surface of the first dielectric layer being co-planar;
• a conductive cap layer selectively positioned over the conductive structures with a top surface and sidewalls;
• a second dielectric layer selectively positioned over the first dielectric layer so that the sidewalls of the conductive cap layer are surrounded by the second dielectric layer;
• a third dielectric layer selectively positioned over the second dielectric layer so that the top surface of the conductive cap layer is lower than a top surface of the third dielectric layer;
• a fourth dielectric layer arranged over the plurality of conductive structures and the third dielectric layer;
• and
• an interconnect structure formed in the fourth dielectric layer, the interconnect structure including a trench structure and a via structure that is positioned below the trench structure and connected to the trench structure, the via structure having a first portion positioned over the conductive cap layer and sidewalls of the first portion being surrounded by the third dielectric layer, and a second portion disposed over the first portion and the third dielectric layer.

A semiconductor device, comprising:

• a first conductive structure formed in a first dielectric layer, the first conductive structure extending into the first dielectric layer from a top surface of the first dielectric layer;
• a conductive cap layer selectively disposed over the first conductive structure with a top surface and sidewalls;
• a dielectric stack selectively disposed over the first dielectric layer, the sidewalls of the conductive cap layer being surrounded by the dielectric stack, a top surface of the dielectric stack being higher than the top surface of the conductive cap layer;
• and
• a second conductive structure formed over the first conductive structure, the second conductive structure having a first portion positioned over the conductive cap layer and sidewalls of the first portion being surrounded by the dielectric stack, and a second portion disposed over the first portion and the dielectric stack, the second portion of the second conductive structure having a larger critical dimension than the first portion of the second conductive structure so as to reduce a resistance of the second conductive structure.