Pulse sequence for plating on thin seed layers

US8500983B2 · kind B2 · utility

Assignee

• Novellus Systems, Inc. · US

Inventors

• Thomas A. Ponnuswamy · Sherwood, US
• Bryan Pennington · Sherwood, US
• Clifford Raymond Berry · West Linn, US
• Bryan L. Buckalew · Tualatin, US
• Steven T. Mayer · Lake Oswego, US

Key dates

• Filing date: May 24, 2010
• Grant date: Aug 6, 2013
• Expiry date: Sep 15, 2030

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C25D17/001
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A plating protocol is employed to control plating of metal onto a wafer comprising a conductive seed layer. Initially, the protocol employs cathodic protection as the wafer is immersed in the plating solution. In certain embodiments, the current density of the wafer is constant during immersion. In a specific example, potentiostatic control is employed to produce a current density in the range of about 1.5 to 20 mA/cm2. The immersion step is followed by a high current pulse step. During bottom up fill inside the features of the wafer, a constant current or a current with a micropulse may be used. This protocol may protect the seed from corrosion while enhancing nucleation during the initial stages of plating.