Interconnect structure and method for forming the same

A method for forming an interconnect structure, comprising:

• forming a first interconnect layer over a substrate, wherein the interconnect layer comprises a metal line through a first dielectric layer;
• forming a blocking layer on the metal line;
• forming a dielectric block covering the first dielectric layer without covering the blocking layer;
• and
• forming a second interconnect layer over the first interconnect layer and the dielectric block, wherein the second interconnect layer comprises a via which extends through a second dielectric layer and lands on the metal line.

A method for forming an interconnect structure, comprising:

• forming a metal line over a substrate;
• forming a first dielectric layer surrounding the metal line, wherein the metal line is sandwiched between a first portion and a second portion of the first dielectric layer;
• forming a first dielectric block and a second dielectric block over the first portion and the second portion of the first dielectric layer respectively;
• forming a second dielectric layer over the first dielectric block, the second dielectric block and the metal line, wherein the second dielectric layer extends between the first dielectric block and the second dielectric block;
• and
• etching the second dielectric layer to form a via hole through a portion of the second dielectric layer between the first dielectric block and the second dielectric block.