WET ETCH REMOVAL OF Ru SELECTIVE TO OTHER METALS

A method for forming a conductive structure for a semiconductor device, comprising:

• depositing a barrier layer in a trench foil led in a dielectric material;
• forming a ruthenium (Ru) interface layer over the barrier layer;
• forming a main conductor over the interface layer;
• recessing the main conductor selectively to the interface layer and the barrier layer to a position below a top surface of the dielectric layer;
• wet etching the interface layer selectively to the main conductor and the barrier layer using a chemical composition including an oxidizer, a buffer agent, a pH adjusting agent in an amount sufficient to provide a basic pH;
• and
• etching the barrier layer selectively to the main conductor and the interface layer.

A method for forming a conductive structure for a semiconductor device, comprising:

• depositing a barrier layer in a trench formed in a dielectric material;
• forming an interface layer over the barrier layer;
• forming a main conductor over the interface layer;
• concurrently recessing the main conductor and the interface selectively to the barrier layer to a position below a top surface of the dielectric layer by wet etching using a chemical composition having an oxidizer and complexing agent, wherein the chemical composition is buffered to include a basic pH;
• and
• etching the barrier layer selectively to the main conductor and the interface layer.

A method for forming a conductive structure for a semiconductor device, comprising:

• depositing a barrier layer in a trench formed in a dielectric material;
• forming a ruthenium (Ru) interface layer over the barrier layer;
• forming a copper (Cu) main conductor over the interface layer;
• concurrently recessing the main conductor and the interface selectively to the barrier layer to a position below a top surface of the dielectric layer by wet etching using a chemical composition having an oxidizer, a buffer agent, a complexing agent and a pH adjusting agent in an amount sufficient to provide a basic pH;
• and
• etching the barrier layer selectively to the main conductor and the interface layer.