Oxidation and Etching Post Metal Gate CMP

摘要

A method includes forming a dummy gate of a transistor at a surface of a wafer, removing the dummy gate, and filling a metallic material into a trench left by the removed dummy gate. A Chemical Mechanical Polish (CMP) is then performed on the metallic material, wherein a remaining portion of the metallic material forms a metal gate of the transistor. After the CMP, a treatment is performed on an exposed top surface of the metal gate using an oxidation-and-etching agent comprising chlorine and oxygen.

主权项

1. A method comprising:
forming a dummy gate for a transistor at a surface of a wafer; removing the dummy gate to form an opening between opposite gate spacers; forming a gate dielectric layer having a portion extending into the opening; depositing a metallic material into the opening; performing a chemical mechanical polish to remove excess portions of the metallic material and the gate dielectric layer, wherein a remaining portion of the metallic material left in the opening forms a metal gate; performing a treatment on a top surface of the metal gate using an oxidation-and-etching solution comprising chlorine and oxygen; and forming a dielectric layer over the treated metal gate.