Cross-contamination control for semiconductor process flows having metal comprising gate electrodes

摘要

A method for fabricating a CMOS integrated circuit (IC) includes providing a semiconductor including wafer having a topside semiconductor surface, a bevel semiconductor surface, and a backside semiconductor surface. A gate dielectric layer is formed on at least the topside semiconductor surface. A metal including gate electrode material including at least a first metal is deposited on the gate dielectric layer on the topside semiconductor surface and on at least a portion of the bevel semiconductor surface and at least a portion of the backside semiconductor surface. The metal including gate electrode material on the bevel semiconductor surface and the backside semiconductor surface are selectively removed to form substantially first metal free bevel and backside surfaces while protecting the metal gate electrode material on the topside semiconductor surface. The selective removing includes a first wet etch that etches the metal gate electrode material highly selectively as compared to the semiconductor, wherein the first wet etch includes a strong oxidizing acid, a weak acid that generally include an organic acid, and a fluoride. The fabrication of the IC including is completed including forming at least one metal interconnect layer after the selectively removing step.