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

A method for modifying a surface of a substrate with a low-temperature, atmospheric pressure plasma in an inert gas environment, comprising:

• 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;
• wherein an inert gas environment is maintained within the chamber throughout the scanning.

An apparatus for modifying a surface of a substrate with a low-temperature, atmospheric pressure plasma in an inert gas environment, comprising:

• a chamber for enclosing the substrate, the chamber having surrounding sidewalls and a movable coverplate above the surrounding sidewalls with a gap therebetween;
• a plasma source affixed to the movable coverplate and having a plasma outlet through the movable coverplate into the chamber;
• an inlet to the chamber for purging the chamber with inert gas sufficient to reduce an oxygen concentration of the chamber to several orders of magnitude less than in air;
• and
• an outlet from the chamber for the inert gas;
• and
• a scanning mechanism for scanning the plasma source by moving the movable coverplate over the substrate and operating the plasma source such as to expose the surface of the substrate to a reactive species generated by the plasma delivered through the plasma outlet;
• wherein an inert gas environment is maintained within the chamber throughout the scanning.