Conductive interconnection structure and manufacturing method thereof

A method of manufacturing a conductive interconnect ion structure, comprising:

• forming a dielectric structure over a conductive feature part, the dielectric structure including a first dielectric layer and a second dielectric layer stacked on each other, the second dielectric layer covering on a top of the first dielectric layer;
• etching the dielectric structure to form a first opening in the dielectric structure, the first opening exposing a portion of the first dielectric layer, and the first opening being used to define a depth and a width of a trench filling portion;
• filling a trench filling material into the first opening to form the trench filling portion, the trench filling material and the second dielectric layer having different etching selectivities;
• etching the trench filling portion to form a second opening in the trench filling portion, the second opening exposing the first dielectric layer located on a bottom surface of the trench filling portion;
• etching the exposed first dielectric layer to form a third opening in the first dielectric layer, the third opening exposing the conductive feature part, and the third opening being used to define a depth and a width of a via portion;
• and
• forming a metal layer in the second opening and the third opening, and one end of the metal layer being electrically connected to the conductive feature part.