Lam Research Corporation

Novellus Systems Incorporated

Clifford Raymond Berry

Bryan Pennington

Jonathan David Reid

Shantinath Ghongadi

Tighe A Spurlin

Manish Ranjan

Lee J Brogan

Ludan Huang

Steven T Mayer

Bryan L Buckalew

Thomas Anand Ponnuswamy

Methods and apparatus for determining whether a substrate includes an unacceptably high amount of oxide on its surface are described. The substrate is typically a substrate that is to be electroplated. The determination may be made directly in an electroplating apparatus, during an initial portion of an electroplating process. The determination may involve immersing the substrate in electrolyte with a particular applied voltage or applied current provided during or soon after immersion, and recording a current response or voltage response over this same timeframe. The applied current or applied voltage may be zero or non-zero. By comparing the current response or voltage response to a threshold current, threshold voltage, or threshold time, it can be determined whether the substrate included an unacceptably high amount of oxide on its surface. The threshold current, threshold voltage, and/or threshold time may be selected based on a calibration procedure.

Monitoring surface oxide on seed layers during electroplating

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.

Pulse sequence for plating on thin seed layers

Growing community of inventors

West Linn, OR, United States of America

Clifford Raymond Berry