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An improved method of treating wastewater to remove ammonia and fluoride is provided. The method comprises the steps of chemical destruction of ammonia with an oxidizing agent, followed by treatment with calcium salts to precipitate insoluble calcium fluoride, and filtration to remove the precipitat

An improved method of treating wastewater to remove ammonia and fluoride is provided. The method comprises the steps of chemical destruction of ammonia with an oxidizing agent, followed by treatment with calcium salts to precipitate insoluble calcium fluoride, and filtration to remove the precipitate.

대표청구항 ▼

An improved method of treating wastewater to remove ammonia and fluoride is provided. The method comprises the steps of chemical destruction of ammonia with an oxidizing agent, followed by treatment with calcium salts to precipitate insoluble calcium fluoride, and filtration to remove the precipitat

An improved method of treating wastewater to remove ammonia and fluoride is provided. The method comprises the steps of chemical destruction of ammonia with an oxidizing agent, followed by treatment with calcium salts to precipitate insoluble calcium fluoride, and filtration to remove the precipitate. coil is carried by said chamber. 22. The system of claim 1 wherein said coil is positioned within said chamber. 23. A semiconductor fabrication system, comprising: a semiconductor fabrication chamber having a plasma generation area within said chamber; a coil positioned to couple energy into said plasma generation area to maintain a plasma in said plasma generation area, said coil having a plurality of voltage values distributed along said coil; and means for shifting said distribution of voltage values in a predetermined continuous path along said coil. 24. The system of claim 23 wherein said shifting means cyclicly shifts said voltage distribution along said coil. 25. The system of claim 23 wherein said shifting means comprises a first continuously variable inductor coupled between said coil and ground. 26. The system of claim 25 wherein said shifting means comprises an RF generator and a second continuously variable inductor coupled between said generator and said coil. 27. The system of claim 26 wherein said first inductor has a first movable core and said second inductor has a second movable core. 28. The system of claim 27 wherein said first movable core is mechanically linked to said second movable core so that movement of said second movable core is responsive to movement of said first movable core. 29. The system of claim 28 wherein said shifting means further comprises a motor for cyclicly moving said first and second movable cores back and forth in unison. 30. The system of claim 27 wherein said first movable core is mechanically linked to said second movable core so that the sum of the inductances of said first and second inductors remains substantially constant during movement of said first and second movable cores. 31. A semiconductor fabrication system, comprising: a semiconductor fabrication chamber having a plasma generation area within said chamber; a coil positioned to couple energy into said plasma generation area to maintain a plasma in said plasma generation area, said coil having a plurality of voltage values distributed along said coil; a first inductor coupled between said coil and ground; and means for changing the inductance of said first inductor so as to shift voltage distributions in a predetermined continuous oath along said coil. 32. The system of claim 31 wherein said first inductor has a first movable core and said changing means comprises means for moving said first core within said first inductor. 33. The system of claim 32 further comprising an RF generator coupled to said coil and a second inductor coupled between said generator and said coil. 34. The system of claim 33 wherein said second inductor has a second movable core and said changing means comprises means for moving said second core within said second inductor. 35. The system of claim 34 wherein changing means comprises means for moving said first core within said first inductor simultaneously with moving said second core within said second inductor. 36. The system of claim 34 wherein said changing means moves said first core within said first inductor and moves said second core within said second inductor so that the inductances of said first and second inductances are changed complementary one to the other. 37. The system of claim 34 wherein said changing means moves said first core within said first inductor and moves said second core within said second inductor so that the sum of the inductances of said first and second inductors remains substantially constant. 38. The system of claim 34 wherein said changing means includes a link mechanically linking said first and second cores so that said first and second cores move in unison. 39. A semiconductor fabrication system for use with an RF generator, comprising: a semiconductor fabrication chamber having a plasma generation area within said chamber; a coil carried by said chamber and positioned to couple energy into said plasma generation area to maintain a plas ma in said plasma generation area, said coil having a first end and a second end wherein said first end is adapted to be coupled to said RF generator; a first variable inductor coupled between said coil second end and ground, said first inductor having a first core adapted to move within said first inductor; and a second variable inductor adapted to be coupled between said coil first end and said RF generator, said second inductor having a second core adapted to move within said second inductor, said second core being mechanically coupled to said first core so that said first and second cores move in unison. 40. A semiconductor fabrication process for sputtering material onto a substrate, the process comprising: energizing a coil of a semiconductor fabrication chamber having a plasma generation area within said chamber, said chamber having a target of said material for sputtering, said coil positioned to couple energy into said plasma generation area to ionize said sputtered target material to form a layer of said sputtered target material on said substrate; and time-averaging voltage distributions along said coil by shifting said voltage distributions in a predetermined continuous path along said coil using an impedance-matching box connected to said coil, said impedance-matching box having a continuously tunable variable reactance. 41. The process of claim 40 wherein said tunable variable reactance includes a tunable inductor. 42. The process of claim 40 wherein said tunable variable reactance includes first and second tunable inductors. 43. The process of claim 42 wherein said tunable variable reactance includes a core piece movably disposed within said first and second tunable inductors. 44. The process of claim 43 wherein said core piece compensates a first change in a first inductive reactance of said first tunable inductor with a second change in a second inductive reactance of said second tunable inductor so as to keep a sum of said first and second inductive reactances substantially constant. 45. The process of claim 44 wherein said first and second tunable inductors are substantially identical. 46. The process of claim 43 wherein said first and second tunable inductors are substantially identical. 47. The process of claim 43 wherein said core piece is substantially ferromagnetic. 48. The process of claim 43 wherein said core piece is substantially nonferromagnetic. 49. The process of claim 42 wherein said first and second tunable inductors are substantially identical. 50. The process of claim 40 wherein said tunable variable reactance includes a variable capacitor. 51. The process of claim 40 wherein said tunable variable reactance includes first and second variable capacitors. 52. The process of claim 51 wherein said tunable variable reactance includes a dielectric piece movably disposed within said first and second variable capacitors. 53. The process of claim 52 wherein said dielectric piece compensates a first change in a first capacitive reactance of said first variable capacitor with a second change in a second capacitive reactance of said second variable capacitor so as to keep a sum of said first and second capacitive reactances substantially constant. 54. The process of claim 53 wherein said first and second variable capacitors are substantially identical. 55. The process of claim 52 wherein said first and second variable capacitors are substantially identical. 56. The process of claim 51 wherein said first and second variable capacitors are substantially identical. 57. The process of claim 40 wherein said tunable variable reactance includes a first inductor having a first movable core, and a second inductor having a second movable core mechanically linked to said first core. 58. The process of claim 40 wherein said tunable variable reactance includes a substantially continuously variable capacitor. 59. The process of claim 40 wherein said tunable variable reactance includes a variable capacitor an d a tunable inductor. 60. A semiconductor fabrication process comprising: energizing a coil positioned to couple energy into a plasma generation area to maintain a plasma in said plasma generation area; and changing the inductance of a first inductor coupled to said coil so as to shift voltage distributions in a predetermined continuous path along said coil. 61. The process of claim 60 wherein said first inductance changing comprises translating a core within said first inductor. 62. The process of claim 60 further comprising changing the inductance of a second inductor coupled to said coil. 63. The process of claim 62 wherein said second inductance changing occurs simultaneously with said first inductance changing. 64. The process of claim 62 wherein said first and second inductance changings are complementary. 65. The process of claim 64 wherein the sum of said first and second inductances remains substantially constant. 66. The process of claim 62 wherein said first inductance changing comprises translating a first core within said first inductor and said second inductance changing comprises translating a second core within said second inductor and linked to said first core. 67. A semiconductor fabrication process, comprising: energizing a coil positioned to couple energy into a plasma generation area to maintain a plasma in said plasma generation area, said coil having a plurality of voltage values distributed along said coil; and; shifting said distribution of voltage values in a predetermined continuous path along said coil. 68. The process of claim 67 wherein said shifting cyclicly shifts said voltage distribution along said coil. 69. The process of claim 67 wherein said shifting uses a first continuously variable inductor coupled between said coil and ground. 70. The process of claim 69 wherein said shifting further uses an RF generator and a second continuously variable inductor coupled between said generator and said coil. 71. The process of claim 70 wherein said shifting includes moving a first movable core of said first inductor and moving a second movable core of said second inductor. 72. The process of claim 71 wherein said first movable core is mechanically linked to said second movable core so that movement of said second movable core is responsive to movement of said first movable core. 73. The process of claim 72 wherein said shifting further comprises using a motor to cyclicly move said first and second movable cores back and forth in unison. 74. The process of claim 71 wherein said first movable core is mechanically linked to said second movable core so that the sum of the inductances of said first and second inductors remains substantially constant during movement of said first and second movable cores. 75. The process of claim 67 wherein said coil is carried by a semiconductor fabrication chamber having said plasma generation area within said chamber. 76. The system of claim 75 wherein said coil is positioned within said chamber. 77. A semiconductor fabrication system, comprising: a semiconductor fabrication chamber having a plasma generation area within said chamber; a coil positioned to couple energy into said plasma generation area to maintain a plasma in said plasma generation area, said coil having a plurality of voltage values distributed along said coil; and a voltage distribution controller adapted to shift said distribution of voltage values in a predetermined continuous path along said coil. 78. The system of claim 77 wherein said controller is adapted to cyclicly shift said voltage value distribution along said coil. 79. The system of claim 77 wherein said controller comprises a first continuously variable inductor coupled between said coil and ground. 80. The system of claim 79 wherein said controller comprises an RF generator and a second continuously variable inductor coupled between said generator and said coil. 81. The system of claim 80 wherein said first inductor has a