Method, chemistry, and apparatus for noble metal electroplating on a microelectronic workpiece

An apparatus for plating a noble metal or noble metal alloy on a microelectronic workpiece comprising:

• a moveable head including a rotor and rotor drive adapted to rotate the workpiece;
• a processing base;
• an electroplating solution disposed in the processing base and containing ions or complexes of the noble metal that is to be plated onto the workpiece;
• a contact assembly disposed on the rotor of the moveable head, the contact assembly providing electroplating power to a peripheral edge surface of a side of the workpiece that is to be plated, the contact assembly contacting the workpiece at a plurality of discrete contact points, the contact points being isolated from exposure to the electroplating solution;
• an actuator disposed to move the moveable head between a loading position in which the workpiece may be placed for support on the rotor and into engagement with the ring contact, and a processing position in which the surface of the workpiece that is to be electroplated is brought into contact with the electroplating solution with the side of the wafer that is to be processed in a face down orientation during electroplating;
• an anode disposed in the electroplating solution in the processing base.

An apparatus for plating a noble metal on a microelectronic workpiece comprising:

• a reactor chamber;
• an electroplating solution containing ions and/or complexes of the noble metal that is to be plated onto the workpiece;
• a workpiece support including a contact assembly for providing electroplating power to a surface at a side of the workpiece that is to be plated;
• an anode spaced from the workpiece support within the reaction chamber and contacting the electroplating solution;
• a chemical delivery system for supplying the electroplating solution to the reactor chamber and recirculating electroplating solution removed from the reactor chamber;
• and
• a multi-stage filtration system disposed within the chemical delivery system for filtering electroplating solution removed from the reactor chamber before it is re-supplied to the reactor chamber, the multi-stage filtration system including at least a first filter stage for filtering particles greater than or equal to a first size and a second filter stage disposed downstream of the first filter stage for filtering particles greater than or equal to a second size and wherein the first size is greater in magnitude than the second size.

An apparatus for plating a noble metal or noble metal alloy on a microelectronic workpiece comprising:

• a reactor chamber;
• an electroplating solution containing ions and/or complexes of the noble metal that is to be plated onto the workpiece;
• a workpiece support including a contact assembly for providing electroplating power to the workpiece that is to be plated;
• an anode spaced from the workpiece support within the reaction chamber and contacting the electroplating solution;
• a disposable current thief disposed in the electroplating solution between the anode and the contact assembly, the disposable current thief comprising conductive portions of a printed circuit board.

A method for electroplating a noble metal on a surface of a microelectronic workpiece, the method comprising the steps of:

• bringing the surface of the workpiece that is to be plated into contact with an electroplating solution including ions and/or complexes of a noble metal that is to be plated on the surface of the workpiece;
• providing an anode spaced from the surface of the workpiece support and contacting the electroplating solution.
• applying electroplating power between the surface of the workpiece and the anode using a low current for a first predetermined period of time;
• applying higher current electroplating power between the surface of the workpiece and the anode for a second predetermined period of time;
• halting application of electroplating power;
• and
• disengaging the surface of the workpiece from the electroplating solution.

An apparatus for plating a noble metal or noble metal alloy on a microelectronic workpiece comprising:

• a reactor chamber;
• an electroplating solution disposed in the reactor chamber, the electroplating solution containing ions or complexes of a noble metal that is to be plated onto the workpiece;
• a workpiece support including a contact for providing electroplating power the workpiece, the workpiece support holding the workpiece so that the side of the workpiece that is to be electroplated is disposed in a face-down orientation for contact with the electroplating solution in the reactor chamber;
• at least one anode spaced from the workpiece support within the reaction chamber and contacting the electroplating solution.