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A workpiece is processed with a plasma in a vacuum plasma processing chamber by exciting the plasma at several frequencies such that the excitation of the plasma by the several frequencies simultaneously causes several different phenomena to occur in the plasma. The chamber includes central top and

A workpiece is processed with a plasma in a vacuum plasma processing chamber by exciting the plasma at several frequencies such that the excitation of the plasma by the several frequencies simultaneously causes several different phenomena to occur in the plasma. The chamber includes central top and bottom electrodes and a peripheral top and/or bottom electrode arrangement that is either powered by RF or is connected to a reference potential by a filter arrangement that passes at least one of the plasma excitation frequencies to the exclusion of other frequencies.

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We claim: 1. A vacuum plasma processor comprising a vacuum chamber including an electrode, the chamber being associated with a reactance, the electrode and reactance being arranged for coupling plasma excitation fields to gas in the chamber, the chamber being arranged for carrying a workpiece while

We claim: 1. A vacuum plasma processor comprising a vacuum chamber including an electrode, the chamber being associated with a reactance, the electrode and reactance being arranged for coupling plasma excitation fields to gas in the chamber, the chamber being arranged for carrying a workpiece while the plasma excitation fields are coupled to the plasma, and a plasma excitation source arrangement having a set of frequencies comprising three frequencies, the source arrangement being arranged for enabling the electrode to couple the electric energy at the frequencies of the set to the plasma incident on the workpiece, the plasma excitation source arrangement being arranged for applying the frequencies of the set to the electrode, the frequencies of the set being such that the excitation of the plasma by frequencies of the set simultaneously causes different phenomena to occur in the plasma, wherein the phenomena affect plasma ion energy, plasma ion density and plasma chemistry of the plasma incident on the workpiece. 2. The vacuum plasma processor of claim 1 wherein the plasma excitation source arrangement is arranged for causing the set of frequencies to be simultaneously applied to the plasma. 3. The vacuum plasma processor of claim 1 wherein the electrode for carrying the workpiece includes a first electrode in the chamber and the reactance includes a second electrode in the chamber. 4. The vacuum plasma processor of claim 3 wherein the plasma excitation source arrangement is arranged for selectively applying, at different operating time periods of the processor, (a) a plurality of the frequencies of the set to the first electrode and at least one of the frequencies, that differs from the plurality of frequencies, to the second electrode, and (b) the frequencies of the set to the first electrode. 5. The vacuum plasma processor of claim 3 wherein the first and second erectrodes and the source arrangement are arranged for causing the second electrode to be at a reference potential and for simultaneously causing the source arrangement to apply the frequencies of the set to the first electrode. 6. The processor of claim 3 wherein a first of the frequencies is in the range of 100 kHz to 10 MHz, a second of the frequencies is in the range of 10 MHz to 150 MHz, and a third of the frequencies is in the range of 27 MHz to 300 MHz. 7. The processor of claim 6 wherein the plasma excitation source arrangement is arranged for selectively simultaneously applying the first and second frequencies to the first electrode while applying the third frequency to the second electrode. 8. The processor of claim 7 wherein the plasma excitation source arrangement is arranged for simultaneously applying the first, second, and third frequencies to the first electrode while the second electrode is at a reference potential. 9. The vacuum plasma processor of claim 1 wherein the plasma excitation source arrangement includes at least one variable frequency RF source. 10. The vacuum plasma processor of claim 1 wherein the plasma excitation source arrangement includes circuitry for (a) providing an impedance match between sources of the frequencies and the plasma and (b) decoupling the frequencies associated with the different sources from each of the other sources. 11. A vacuum plasma processor for a workpiece comprising a vacuum chamber including first and second electrodes for supplying plasma excitation fields to a region of the chamber adapted to be responsive to gas adapted to be converted into a plasma for processing the workpiece, the chamber being arranged for carrying the workpiece while the plasma exciting fields are supplied to the region, a plasma excitation source arrangement having a set of frequencies, the set of frequencies including three frequencies, the plasma source arrangement being arranged for deriving electric energy at the set of frequencies, the plasma excitation source arrangement including circuitry for coupling the frequency of the set to the first electrode for enabling plasma exciting electric fields at the frequency of the set to be coupled to the plasma. 12. The processor of claim 11 wherein the circuitry is arranged for selectively coupling a plurality of the frequencies of the set to the first electrode and for selectively coupling at least one of the frequencies of the set to the second electrode, the at least one frequency being different from the plurality of frequencies, the circuitry being arranged so the frequencies of the set are applied to the first electrode during a first operating time period of the processor that is different from a second operating time period of the processor while the plurality of the frequencies of the set are applied to the first electrode and at least one of the frequencies of the set is applied to the second electrode. 13. The processor of claim 11 wherein the circuitry is arranged for (a) providing an impedance match between sources of the frequencies of the set and the plasma and (b) decoupling the frequencies associated with the different sources from each of the other sources. 14. The processor of claim 11 wherein the plasma excitation source arrangement includes different frequency sources, one for each frequency of the set. 15. The processor of claim 14 wherein at least one of the sources has a variable frequency. 16. The processor of claim 14 wherein at least one of the sources has a fixed frequency. 17. The processor of claim 14 wherein various combinations of the frequencies of the set affect (a) the density of the plasma, (b) the energy of ions in the plasma, and (C) the chemistry of the plasma. 18. The processor of claim 14 wherein at least one of the sources has a variable output power. 19. The processor of claim 11 wherein the circuitry and the chamber are arranged for preventing substantial current to flow at at least one of the plurality of frequencies of the set to the second electrode. 20. The processor of claim 11 wherein the circuitry is arranged for connecting the second electrode to a reference potential and for supplying the frequencies of the set to the first electrode. 21. The processor of claim 11 wherein the circuitry is arranged for supplying the same frequency to the first and second electrodes. 22. The processor of claim 11 wherein the plasma source arrangement circuitry is arranged for simultaneously coupling the three or more frequencies of the set to the electrodes. 23. The vacuum plasma processor of claim 11 wherein the plasma excitation source arrangement is arranged for applying the frequencies of the set to the first electrode. 24. The vacuum plasma processor of claim 11 wherein the first and second electrodes and the source arrangement are arranged for causing the second electrode to be at a reference potential and for simultaneously causing the source arrangement to apply the frequencies of the set to the first electrode. 25. The processor of claim 11 wherein a first of the frequencies is in the range of 100 kHz to 10 MHz, a second of the frequencies is in the range of 10 MHz to 150 MHz, and a third of the frequencies is in the range of 27 MHz to 300 MHz. 26. A vacuum plasma processor for a workpiece comprising a vacuum chamber including first and second electrodes for supplying plasma excitation fields to a region of the chamber adapted to be responsive to gas adapted to be converted into a plasma for processing the workpiece, the chamber being arranged for carrying the workpiece while the plasma exciting fields are supplied to the region, a plasma excitation source arrangement having a set of frequencies comprising three frequencies, the plasma excitation source arrangement including circuitry for selectively enabling coupling of the set of frequencies to at least one of the first and second electrodes for enabling plasma exciting electric fields at the set of frequencies to be coupled to the plasma, the circuitry and the chamber being arranged for preventing substantial current to flow at said at least one of the frequencies of the set to the second electrode; the circuitry and the chamber arrangement for preventing the substantial current to flow including; (a) a surface in the chamber at a reference potential for causing current to flow at said at least one of the frequencies of the set from the first electrode to the surface and (b) a filter arrangement of the circuitry, the filter arrangement being connected to the second electrode for preventing the substantial flow of current at said at least one of the plurality of frequencies between the second electrode and the reference potential. 27. A vacuum plasma processor for a workpiece comprising a vacuum chamber including first and second electrodes for supplying plasma excitation fields to a region of the chamber adapted to be responsive to gas adapted to be converted into a plasma for processing the workpiece, the chamber being arranged for carrying the workpiece while the plasma exciting fields are supplied to the region, a plasma excitation source arrangement for deriving electric energy at a set of frequencies, the set of frequencies comprising three frequencies, the plasma excitation source arrangement including circuitry for selectively enabling coupling of the frequencies of the set to at least one of the first and second electrodes for enabling plasma exciting electric fields at the frequencies of the set to be coupled to the plasma, the circuitry and the chamber including a controller for selectively connecting the second electrode to a reference potential during a first workpiece processing time period and for selectively supplying the same frequency to the first and second electrodes during a second work piece processing time period. 28. The processor of claim 27 wherein the controller is arranged for selectively connecting the first electrode to be responsive to each of the frequencies of the set during the first time period. 29. A vacuum plasma processor for processing a workpiece comprising a vacuum chamber including an electrode arrangement for supplying plasma excitation fields to a region of the chamber adapted to be responsive to gas adapted to be converted into a plasma for processing the workpiece, the chamber being arranged for carrying the workpiece while the plasma excitation fields are supplied to the region, the electrode arrangement including first and second electrodes respectively on opposite first and second sides of the region and a third electrode on said first side of the region, the third electrode being peripheral to and electrically insulated from the first electrode, a plasma excitation source arrangement for deriving electric energy at plural frequencies, the plasma excitation source arrangement being arranged for selectively coupling energy at the plural frequencies to the first, second and third electrodes for causing current at at least one of the plural frequencies to flow in the third electrode without current at all of the frequencies flowing in the third electrode. 30. The processor of claim 29 wherein the electrode arrangement includes a fourth electrode on said second side of the region, the fourth electrode being peripheral to and electrically insulated from the second electrode, the plasma excitation source arrangement being arranged for selectively coupling energy to the fourth electrode for causing current at at least one of plural frequencies to flow in the fourth electrode without current at all the frequencies flowing through the fourth electrode. 31. The processor of claim 30 wherein the plasma excitation source arrangement is arranged for applying energy at at least one of the frequencies to the third electrode. 32. The processor of claim 30 wherein the plasma excitation source arrangement is arranged for applying energy at at least one of the frequencies to the fourth electrode. 33. The processor of claim 30 wherein the plasma excitation source arrangement is arranged for applying energy at at least one of the frequencies to the third and fourth electrodes. 34. The processor of claim 30 wherein the plasma excitation source arrangement includes a filter arrangement for enabling current at least one of the frequencies to flow between the third electrode and a reference potential while preventing current at at least one of the frequencies from flowing between the third electrode and the reference potential. 35. The processor of claim 30 wherein the plasma excitation source arrangement includes a filter arrangement for enabling current at at least one of the frequencies to flow between the fourth electrode and a reference potential while preventing current at at least one of the frequencies from flowing between the fourth electrode and the reference potential. 36. The processor of claim 35 wherein the plasma excitation source arrangement includes a filter arrangement for enabling current at at least one of the frequencies to flow between the third electrode and a reference potential while preventing current at least one of the frequencies from flowing between the third electrode and the reference potential. 37. The processor of claim 29 wherein the plasma excitation source arrangement is arranged for applying energy at at least one of the frequencies to the third electrode. 38. The processor of claim 29 wherein the plasma excitation source arrangement includes a filter arrangement for enabling current at at least one of the frequencies to flow between the third electrode and a reference potential while preventing current at least one of the frequencies from flowing between the third electrode and the reference potential. 39. A vacuum plasma processor comprising a vacuum chamber including therein a first electrode and a second electrode, the first and second electrodes being arranged for coupling plasma excitation fields to gas in the chamber, the chamber being arranged for carrying a workpiece while the plasma excitation fields are coupled to the plasma, and a plasma excitation source arrangement for enabling the first and second electrodes to couple the electric energy at a set of frequencies to the plasma incident on the workpiece, the set of frequencies comprising three frequencies, wherein the plasma excitation source arrangement is arranged for simultaneously applying first, second, and third frequencies of the set to the first electrode while the second electrode is at a reference potential, the first of the frequencies being in the range of 100 kHz to 10 MHz, the second of the frequencies being in the range of 10 MHz to 150 MHz, and the third of the frequencies being in the range of 27 MHz to 300 MHz. 40. The vacuum plasma processor of claim 39 wherein the plasma excitation source arrangement is arranged for causing the three or more frequencies to be simultaneously applied to the plasma. 41. The processor of claim 39 wherein the plasma excitation source arrangement is arranged for simultaneously applying the first and second frequencies to the first electrode while applying the third frequency to the second electrode the source arrangement being arranged so that during first operating time periods of the processor on the first electrode is at the reference potential and during the second operating time periods of the processor the third frequency is applied to the second electrode. 42. The vacuum plasma processor of claim 39 wherein the plasma excitation source arrangement is arranged for selectively applying a plurality of the frequencies of the set to the first electrode and at least one of the frequencies of the set, that differs from the plurality of frequencies, to the second electrode. 43. The vacuum plasma processor of claim 39 wherein the plasma excitation source arrangement includes at least one variable frequency RF source. 44. The vacuum plasma processor of claim 39 wherein the plasma excitation source arrangement includes circuitry for (a) providing an impedance match between sources of the frequencies and the plasma and (b) decoupling the frequencies associated with the different sources from each of the other sources. 45. The vacuum plasma processor of claim 39 wherein the excitation source arrangement is arranged and the frequencies have values for causing three or more different phenomena to occur simultaneously in the plasma.