A method to eliminate coil sputtering in an inductively coupled plasma (ICP) source

摘要

The disclosure relates to a plasma generator comprising a substantially cylindrical plasma chamber (100) which is received in a vacuum chamber (102). The plasma chamber has a single helical coil (104) which is carried internally of the vacuum chamber walls 108 by a chamber shield (106). The chamber shield 106 protects the interior walls 108 of the vacuum chamber from the material being deposited within the interior of the plasma chamber. Radio frequency (RF) energy from an RF generator (3040) is radiated from the coil (104) into the interior of the plasma chamber, which energizes a plasma within the plasma chamber. An ion flux strikes a negatively biased target (110) positioned above the plasma chamber. The plasma ions eject material from the target onto a substrate (112) which may be a wafer or other workpiece supported by a pedestal 114 at the bottom of the plasma chamber. A rotating magnet assembly (116) provided above the target produces magnetic fields which sweep over the face of the target to promote uniform erosion by sputtering of the target. The coil (104) is magnetically shielded by magnetic fields generated by electromagnet coils (1000) and (1010) so as to minimize sputtering of material from the coil. In addition, the deposition of target material onto the coil may also be reduced. As a consequence, contamination of the substrate (112) by material sputtered from the coil or by particulate matter shed by the coil may be reduced. <IMAGE> <IMAGE>