Electroplating with reduced air bubble defects
OwnerPaul R. McHugh, Gregory J. Wilson +4inventors
InventorsPaul R. McHugh, Gregory J. Wilson, John L. Klocke, Randy A. Harris, Bridger Hoerner, Paul Van Valkenburg
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Abstract
A method for processing a wafer includes holding the wafer in a face-up position with a seal ring contacting the wafer on a contact circumference. A bead of liquid is applied onto the entire contact circumference, with the bead of liquid contacting the wafer and the seal ring. The wafer is then inverted into a head-down position, lowered into contact with electrolyte and plated with a conductive film. Formation of the bead of liquid helps to displace air bubbles as the wafer is immersed into the electrolyte which reduces plating defects.
Claims17
A method for processing a wafer, comprising:
- A] holding a wafer in a contact ring having a seal;
- B] applying a bead of liquid directly from a liquid outlet onto the seal, with the bead of liquid contacting the wafer and the seal ring;
- C] moving the wafer into contact with an electrolyte;
- and
- D] conducting electrical current through the electrolyte and through a conductive layer on the wafer.
Processing apparatus comprising:
- a vessel for holding an electrolyte;
- a head supported on a lift/rotate mechanism;
- a rotor rotatably supported on the head;
- a rotor motor in the head for rotating the rotor;
- a contact ring on the rotor having contact fingers for making electrical contact with a conductive layer of a wafer held in the rotor;
- a seal on the contact ring adapted to seal against the wafer;
- and
- a liquid bead supply tube having an outlet for applying a bead of liquid directly onto the seal and the wafer.
A method for processing a wafer, comprising:
- A] tilting wafer to an angle of 1 to 5 degrees relative to a horizontal surface of electrolyte in a vessel;
- B] moving the wafer at from 125 to 300 mm/sec into the electrolyte;
- C] decelerating the moving tilted wafer to a stop within 0.05 to 1.0 seconds, with a leading edge of the wafer below a meniscus level of the electrolyte sufficient to allow full wetting of an entire wafer down-facing surface;
- D] returning the wafer to a flat horizontal position;
- and
- E] moving the wafer further down to a processing position in the electrolyte.
Dependencies are inferred from the claim text.