Patent ID: 7273533

Claim:
An ICP source for producing a high-density inductively coupled plasma in a vacuum chamber for the plasma processing of a semiconductor wafer therein, the source comprising: a dielectric chamber wall having a vacuum side and an atmospheric side and formed of at least one section of dielectric material; a peripheral ionization source including an RF antenna on the atmospheric side of the dielectric chamber wall and a shield on the vacuum side of the dielectric chamber wall; the peripheral ionization source having a segmented configuration of alternating high-radiation and low-radiation segments arranged in a ring and positioned to couple power through the dielectric chamber wall into the chamber to produce a plasma having an annular, alternating, high and low power distribution; the shield having alternating high-transparency and low-transparency sections arranged in a ring and positioned relative to the antenna to facilitate the coupling of RF energy from the antenna through the dielectric chamber wall and the shield and into the chamber in the annular, alternating, high and low power distribution, the high-radiation segments including the high-transparency sections of the shield and the low-radiation segments including the low-transparency sections of the shield; and the high-transparency sections of the shield each having a plurality of slots therethrough oriented relative to the antenna to facilitate the inductive coupling through the high-transparency sections, and the low-transparency sections of the shield being solid electrically conductive sections with no slots to impede inductive coupling there-through; the RF antenna has a segmented configuration arranged in a ring that includes high-efficiency sections formed of small cross-section conductors that provide concentrated antenna current paths close to the dielectric chamber wall and low-efficiency sections formed of relatively large cross-section conductors that provide distributed antenna current paths, whereby stronger magnetic fields are produced adjacent the high-efficiency sections of the conductor than adjacent the low-efficiency sections of the conductor; and the high-efficiency sections of the antenna are aligned with the high-transparency sections of the shield to form the high-radiation segments of the peripheral ionization source and the low-efficiency sections of the antenna are aligned with the low-transparency sections of the shield and form the low-radiation segments of the peripheral ionization source.