Semiconductor structure and manufacturing method thereof

A manufacturing method of a semiconductor structure, comprising:

• forming a trench in a first interlayer dielectric (ILD) layer;
• filling a metal conductor with metal dopants in the trench;
• performing planarization on the metal conductor with the metal dopants;
• forming a metal capping layer on the metal conductor with the metal dopants;
• performing a thermal treatment, a photo treatment or a bias-assist treatment on the metal conductor with the metal dopants to form a self-aligned etching stop layer and a first metal layer, wherein the self-aligned etching stop layer is formed on the metal capping layer;
• forming a conformal etching stop layer on the first interlayer dielectric layer and the self-aligned etching stop layer to form an etching stop bi-layer structure;
• and
• forming a via, a second interlayer dielectric (ILD) layer and a second metal layer, wherein the via is embedded in the second interlayer dielectric layer and the via is disposed between the first metal layer and the second metal layer.

A semiconductor structure, comprising:

• a first interlayer dielectric (ILD) layer;
• a first metal layer, embedded in the first interlayer dielectric layer;
• a metal capping layer, disposed on the first metal layer;
• an etching stop bi-layer structure, including:
• a self-aligned etching stop layer, disposed on the metal capping layer;
• a first hermetic layer, disposed on the self-aligned etching stop layer;
• and
• a conformal etching stop layer, disposed on the first interlayer dielectric layer and the self-aligned etching stop layer, wherein the metal capping layer, the self-aligned etching stop layer, the first hermetic layer and the conformal etching stop layer are stacked in sequence;
• a second interlayer dielectric (ILD) layer, disposed on the etching stop bi-layer structure;
• a via, embedded in the second interlayer dielectric layer;
• and
• a second metal layer, embedded in the second interlayer dielectric layer and disposed on the via.