Semiconductor structure and manufacturing method thereof

A semiconductor structure, comprising:

• a metal layer, having a concave;
• a metal-organic framework layer, disposed in the concave;
• and
• an air gap, located in the concave, wherein the air gap is located between the metal-organic framework layer and a bottom of the concave.

A manufacturing method of a semiconductor structure, comprising:

• forming a contact layer in a dielectric layer;
• forming a capping layer on the contact layer;
• forming a glue layer on the dielectric layer and the capping layer;
• forming a metal layer on the glue layer;
• forming a hard mask on the metal layer;
• patterning the hard mask;
• etching the metal layer and the glue layer to form at least one concave;
• forming a dielectric capping layer on a bottom and a lateral wall of the concave;
• forming a sacrificial layer in the concave;
• recessing the sacrificial layer;
• filling a metal-organic framework layer in the concave;
• removing the sacrificial layer to form an air gap in the concave;
• polishing the metal-organic framework layer and the metal layer;
• forming an etching stop layer on the metal-organic framework layer and the metal layer;
• forming a low-k material layer on the etching stop layer;
• patterning the low-k material layer to forming at least one opening exposing part of the metal layer;
• and
• forming a conductive layer in the opening to connect to the metal layer.