Low copper electroplating solutions for fill and defect control

Abstract

Certain embodiments herein relate to a method of electroplating copper into damascene features using a low copper concentration electrolyte having less than about 10 g/L copper ions and about 2-15 g/L acid. Using the low copper electrolyte produces a relatively high overpotential on the plating substrate surface, allowing for a slow plating process with few fill defects. The low copper electrolyte may have a relatively high cloud point.

What is claimed is: 
     
         1 . A method of plating copper into damascene features, comprising:
 receiving a substrate having a seed thickness of about 200 nanometers, on average, or thinner;   electrically biasing the substrate;   immersing the substrate in an aqueous low copper acid-containing electrolyte comprising less than about 10 grams per liter copper ions and at least one suppressor compound, whereby the low copper electrolyte induces a cathodic overpotential on the seed sufficient to protect the seed from dissolution by acid in the electrolyte during immersion;   electroplating copper into the features at a current density of about 3 mA/cm 2  or less; and   removing the substrate from the electrolyte.