Rf sensing apparatus of plasma processing chamber and plasma processing chamber including same

A Radio Frequency (RF) sensing apparatus introduced to a plasma processing chamber, the RF sensing apparatus comprising:

• a conducting rod through which a conducting rod current flows in one direction;
• a current return unit through which a return current flows in another direction opposite to the one direction, that at least partially encompasses the conducting rod, that is physically separated from the conducting rod, and that includes a main return path unit and a secondary return path unit;
• and
• a current sensing unit disposed between the main return path unit and the secondary return path unit,
• wherein a remaining portion of the return current flowing in the secondary return path unit is less than a majority of the return current flowing in the main return path unit.

A Radio Frequency (RF) sensing apparatus introduced to a plasma processing chamber, the RF sensing apparatus comprising:

• a main return path unit having a centrally disposed through-hole in an up/down direction and electrically conducting a measurement current in the up/down direction;
• a secondary return path unit spaced apart from an inner side surface of the main return path unit, having a centrally disposed through-hole in the up/down direction, and electrically conducting a return current in the up/down direction;
• and
• a coil-type wiring disposed between the main return path unit and the secondary return path unit.