Reduction in number of sparks generated in high-density plasma process by fixing the wall potential

The effect of the existence of floating potential on spark generation during high-density plasma processes was investigated using an electromagnetic sensor and an on-wafer monitoring sensor. It was observed that the marked change in the potential corresponded to the occurrence of sparks. It was also shown that the connection between the shielding wall and the grounded line significantly reduced the number of generated sparks as compared with that in the case of the existence of a floating shielding wall. Accordingly, it was found that the existence of a floating wall is one of the main reasons for spark generation, and that fixing the wall potential is very effective for preventing spark generation.