Method of making embedded wiring system

A method of preparing a multilevel embedded wiring system for an integrated circuit (IC) comprising a first wiring formation step, a first connecting portion formation step, and a second wiring formation step, wherein

• said first wiring formation step comprises
• forming a first trench for a first embedded wiring in a first insulating layer disposed on a substrate, and
• embedding in the first trench, sequentially, a first conductive layer and a first conductive capping layer by depositing a conductive material on the first insulating layer and in the first trench, flattening a top surface of the conductive material by Chemical Mechanical Polishing (CMP) to leave the conductive material only in the first trench, forming a recess in the conductive material in the first trench, and embedding a conductive capping material in the recess to form the first conducting capping layer;
• said first connecting portion formation step comprises forming a second insulating layer on said first insulating layer and said first conductive capping layer, forming a via-hole in a part of said second insulating layer at said first conductive capping layer, and embedding a conductive connecting portion in the via-hole and connected to said first conductive layer;
• and
• said second wiring formation step comprises forming a third insulating layer on said second insulating layer and said conductive connecting portion, forming a second trench for a second wiring in said third insulating layer at said conductive connecting portion, and embedding a second conductive layer in the second trench and connected to said conductive connecting portion.