Interconnect structure and manufacturing method for the same

A method for forming an interconnect structure, comprising:

• forming a first metal line;
• forming a sacrificial layer above the first metal line;
• removing an upper portion of the sacrificial layer with a first mask;
• forming a dielectric layer over the sacrificial layer subsequent to removing the upper portion of the sacrificial layer;
• removing a portion of the dielectric layer over the first metal line with the first mask;
• removing a lower portion of the sacrificial layer to form a through recess;
• and
• forming a conductive post in the through recess.

A method for forming an interconnect structure, comprising:

• forming a first metal line;
• forming a sacrificial bilayer over the first metal line, wherein the sacrificial bilayer comprises a first sacrificial layer and a second sacrificial layer over the first sacrificial layer;
• forming an anti-reflective layer over the sacrificial bilayer;
• forming a first recess in the second sacrificial layer to expose a top surface of the first sacrificial layer;
• removing the anti-reflective layer after exposing the top surface of the first sacrificial layer;
• forming a dielectric layer over the sacrificial bilayer;
• forming a second recess in the first sacrificial layer and directly below the first recess, wherein a portion of the first sacrificial layer is free from being under a coverage of a vertical projection area of the second sacrificial layer subsequent to forming the second recess;
• and
• forming a conductive material in the first and second recess.