Apparatuses and methods for controlling PH in electroplating baths

摘要

Disclosed are methods of electroplating a metal onto a substrate surface in an electroplating bath and adjusting the pH of the bath. The methods may include exposing the substrate surface, a counter-electrode, and an acid generating surface to the bath, biasing the substrate surface sufficiently negative relative to the counterelectrode such that metal ions from the bath are reduced and plated onto the substrate surface, and biasing the acid generating surface sufficiently positive relative to the counterelectrode such that free hydrogen ions are generated at the acid generating surface thereby decreasing the pH of the bath. Also disclosed are apparatuses for electroplating metal onto a substrate surface in an electroplating bath, and for adjusting the pH of the electroplating bath. The apparatuses may include an acid generating surface configured to generate free hydrogen ions in the bath upon supply of sufficient positive voltage bias relative to a counterelectrode electrical contact.

主权项

1. A method of electroplating a metal onto a surface of a patterned semiconductor substrate in an electroplating bath and adjusting the pH of the bath, the method comprising:
placing the substrate into an electroplating clamshell and exposing the substrate surface to the bath; exposing a counter-electrode to the bath; biasing the substrate surface sufficiently negative relative to the counterelectrode such that metal ions from the bath are reduced and plated onto the substrate surface; replacing the substrate with an acid generating disc having an acid generating surface in the electroplating clamshell and exposing said surface to the bath; and biasing the acid generating surface sufficiently positive relative to the counterelectrode such that hydrogen ions are generated at the acid generating surface thereby decreasing the pH of the bath.