Interconnect structure

An interconnect structure, comprising:

• a first metal line in a first dielectric layer;
• a dielectric block over the first dielectric layer;
• an etching stop layer over the dielectric block and the first metal line, wherein the etching stop layer includes a first horizontal portion along a top surface of the first metal line, a first vertical portion along a sidewall of the dielectric block, and a second horizontal portion along a top surface of the dielectric block, and a bottom surface of the first horizontal portion of the etching stop layer is lower than a bottom surface of the dielectric block;
• a second dielectric layer covering the first horizontal portion and the second horizontal portion of the etching stop layer;
• and
• a catalyst layer between the dielectric block and the first dielectric layer, wherein the bottom surface of the first horizontal portion of the etching stop layer is level to a bottom surface of the catalyst layer.

An interconnect structure, comprising:

• a first dielectric layer over a substrate;
• a first metal line and a second metal line through the first dielectric layer;
• a dielectric block over the first dielectric layer;
• an etching stop layer along an upper surface and a sidewall of the dielectric block and an upper surface of the second metal line;
• a second dielectric layer over the etching stop layer;
• a via extending through the second dielectric layer, the etching stop layer, and the dielectric block to the first metal line;
• and
• a blocking layer between the second metal line and the etching stop layer, wherein the blocking layer includes amphiphilic organic molecules.