Chemical-mechanical polishing method and apparatus using ultrasound applied to the carrier and platen

An apparatus for simultaneously chemically, mechanically and ultrasonically polishing a surface of a semiconductor wafer, the apparatus comprising:

• a rotatable carrier with a downwardly facing surface, the semiconductor wafer to be polished being bonded to the downwardly facing surface of the carrier, the carrier further comprising a first ultrasonic transmitter for transmitting ultrasonic wave energy through the carrier to the wafer, the first transmitter being connected to a first oscillator for driving the first transmitter,
• a rotatable platen with an upwardly facing surface, a polishing pad being bonded to the upwardly facing surface of the platen, the platen further comprising a second ultrasonic transmitter for transmitting ultrasonic wave energy through the platen, through the pad and to the wafer, the second transmitter being connected to a second oscillator for driving the second transmitter,
• a port for supplying polishing slurry to the pad,
• at least one of the platen or the carrier being vertically positionable so that the pad and slurry disposed on the pad engages the wafer with a pressure,
• a controller for simultaneously activating the first and second oscillators for a simultaneous transmission of ultrasonic wave energy through the carrier and through the platen.