| 摘要 |
PURPOSE:To improve detection accuracy by detecting contamination and purification degree in the plasma apparatus from a current or voltage value applied to the detecter from discharged plasma. CONSTITUTION:A metal 5 such as platinum covered with an insulator 3 such as quartz and is exposed at the surface 4 within a plasma apparatus is mounted to an internal wall 2 of a dry etching apparatus 1 and a voltage applying circuit 6, a current measuring circuit 7 and an earth 8 are coupled thereto. Immediately after the purification, namely after start of discharging, a film of decomposed product of gas used for dry etching is adhered to the surface of detecter. Therefore, a current does not flow. However, the film is ashed by the oxygen plasma with time and the film becomes thinner. Accordingly a current starts to flow and increases. When the film is perfectly removed, a current saturates. Namely, when a current saturates, purification is completed. |
