Automatic in-situ control of an electro-plating processor

Abstract

In an electroplating processor having at least one anode and one thief electrode, reference electrodes are used to measure a voltage gradient in the electrolyte near the edge of the wafer. The voltage gradient is used to calculate the current at the wafer surface using a control volume / current balance technique. The fraction of the total wafer current flowing to the edge region of the wafer is determined and compared to a target value. The processor controller changes at least one of the anode and thief currents to bring the actual edge region current toward the target current.

Description

technical field [0001] The present application relates to chambers, systems and methods for electrochemically processing wafers of semiconductor material and similar workpieces or substrates with microdevices. Background technique [0002] Microelectronic devices, such as semiconductor devices, are typically fabricated on and / or in wafers or workpieces of semiconductor material using several different types of machines. In a typical manufacturing process, one or more layers of a conductive material, such as metal, are formed on a wafer. The wafer is then typically etched or polished to remove portions of the conductive layer to form contacts, conductive lines, or other features. [0003] As microelectronic devices are made smaller and smaller, the seed layer also needs to be made thinner. With very thin seed layers, the sheet resistance at the beginning of the plating process can be as high as, for example, 50 Ohm / sq (Ohm / sq), whereas the final sheet resistance of the plat...

AI Technical Summary

Problems solved by technology

Even with careful selection of electrode set points, the quality and characteristics of the resulting plating or film may be less than ideal due to the large number of variables involved

Images