Semiconductor structure, method for forming same and stacked structure

A method for forming a semiconductor structure, comprising:

• providing a base, wherein the base comprises a substrate and a dielectric layer, the substrate is provided with a front surface and a back surface which are oppositely arranged, and the dielectric layer is formed on the front surface;
• forming a connecting hole in the base, wherein the connecting hole penetrates through the substrate and extending to the dielectric layer;
• forming an insulating layer on a surface of an inner wall of the connecting hole;
• and
• forming a connecting structure on a surface of the insulating layer, wherein the connecting structure comprises a first barrier layer, a second barrier layer and a conductive structure, the first barrier layer is located on the surface of the insulating layer, the second barrier layer is located between the first barrier layer and the conductive structure, and an air gap exists between the second barrier layer and the first barrier layer, wherein
• the connecting structure further comprises an isolation layer, and said forming the connecting structure on the surface of the insulating layer comprises:
• forming a first barrier layer on the surface of the insulating layer;
• forming a primary isolation layer on a surface of the first barrier layer, wherein the primary isolation layer comprises a side wall portion;
• forming a primary barrier layer on a surface of the primary isolation layer;
• forming a primary conductive layer on a surface of the primary barrier layer;
• removing part of the primary conductive layer and part of the primary barrier layer so as to expose part of the side wall portion, wherein the retained part of the primary conductive layer constitutes a first conductive layer, and the retained part of the primary barrier layer constitutes a first sub-layer;
• removing part of the side wall portion, wherein the retained part of the primary isolation layer constitutes an isolation layer, and a distance between a top surface of the isolation layer and an opening of the connecting hole is greater than a distance between a top surface of the first sub-layer and the opening of the connecting hole;
• forming a second base layer on the surface of the first barrier layer, a surface of the first sub-layer and a surface of the first conductive layer;
• and
• forming a second conductive layer, wherein the second conductive layer and the first conductive layer constitutes the conductive structure.

A semiconductor structure, comprising:

• a base, comprising a substrate and a dielectric layer, wherein the substrate has a front surface and a back surface which are oppositely arranged, and the dielectric layer is located on the front surface;
• a connecting hole, penetrating through the substrate and extending to the dielectric layer;
• an insulating layer, located on a surface of an inner wall of the connecting hole;
• and
• a connecting structure, comprising a first barrier layer, a second barrier layer and a conductive structure, wherein the first barrier layer is located on a surface of the insulating layer, the second barrier layer is located between the first barrier layer and the conductive structure, and an air gap exists between the second barrier layer and the first barrier layer, wherein
• the connecting structure further comprises an isolation layer, the isolation layer is located between the first barrier layer and the second barrier layer, the first barrier layer, the isolation layer, the second barrier layer and the conductive structure are arranged together defining the air gap, and the air gap is sealed by the conductive structure.