Post rinse to improve selective deposition of electroless cobalt on copper for ULSI application

A method of processing a substrate, comprising:

• polishing a substrate surface to expose a conductive material disposed in a dielectric material;
• selectively depositing an initiation layer on the conductive material by exposing the substrate surface to a first electroless solution consisting essentially of one or more boron based reducing agents;
• depositing a passivating material on the initiation layer by exposing the initiation layer to a second electroless solution;
• and
• cleaning the substrate surface with an acidic solution.

A method of processing a substrate, comprising:

• selectively depositing an initiation layer on a conductive material by exposing the substrate surface to a first electroless solution consisting essentially of one or more boron based reducing agents:
• depositing a passivating material on the initiation layer by exposing the initiation layer to a second electroless solution:
• and
• cleaning the substrate surface with an acidic solution selected from the group consisting of nitric acid and deionized water at a ratio of about 1:2 to about 3:1;
• nitric acid and hydrogen peroxide at a ratio of about 1:2 to about 3:1;
• sulfuric acid and hydrogen peroxide at a ratio of about 2:1 to about 4:1;
• and hydrochloric acid and hydrogen peroxide at a ratio of about 2:1 to about 4:1.