Methods of manufacturing semiconductor device

A method of manufacturing a semiconductor device, comprising:

• forming a patterned mask over a chemical mechanical polishing (CMP) stop layer, wherein the CMP stop layer is disposed over a first interlayer dielectric (ILD) layer, and the first ILD layer is disposed over a substrate;
• performing an etching process using the patterned mask to form a trench through the CMP stop layer and into the first ILD layer;
• removing the patterned mask;
• forming a metal layer in the trench and over portions of the CMP stop layer outside the trench;
• forming a sacrificial layer over the metal layer;
• performing a CMP operation on the sacrificial layer and the metal layer to expose portions of the metal layer and the sacrificial layer in the trench and to expose the CMP stop layer outside the trench;
• and
• removing the sacrificial layer from over the metal layer in the trench.

A method of manufacturing a semiconductor device, comprising:

• forming a trench in a layered structure comprising a dielectric layer disposed over a substrate, and a chemical mechanical polishing (CMP) stop layer disposed over the dielectric layer, wherein the trench penetrates the CMP stop layer and extends into the dielectric layer;
• forming a metal layer in the trench and over the CMP stop layer;
• forming a sacrificial layer over the metal layer;
• performing a CMP operation on the sacrificial layer and the metal layer to expose portions of the metal layer and the sacrificial layer in the trench and to expose the CMP stop layer outside the trench;
• and
• removing the sacrificial layer from the trench.