Removing metal oxide from metallic contacts on substrates, dies and wafers with atmospheric pressure plasma

Abstract

A method for modifying a surface of a substrate with a plasma in an inert gas environment, comprises enclosing the substrate in a chamber having surrounding sidewalls and a movable coverplate above the surrounding sidewalls with a gap therebetween, affixing a plasma source to the movable coverplate having a plasma outlet through the coverplate into the chamber, purging the chamber with inert gas sufficient to reduce an oxygen concentration of the chamber to several orders of magnitude less than in air, the inert gas entering through and inlet to the chamber and exiting through an outlet from the chamber, and scanning and activating the plasma source affixed to the cover plate over the substrate, such as to expose the surface of the substrate to a reactive species generated by the plasma delivered through the plasma outlet. An inert gas environment is maintained within the chamber throughout the scanning.