Development of in-situ plasma density monitoring method in inductively coupled plasma

Summary form only given, as follows. There are many demands on monitoring the plasma density without perturbing to the plasma of the processing chamber. Here we present the possibility of monitoring the plasma density without using any electrical and optical probing systems. The newly developed monitoring method is based on the Godyak plasma impedance model, assuming the electron temperature is constant with power and operating pressure, the plasma density can be obtained from the balance between input and the plasma powers. The plasma impedance was obtained by measuring voltage and current supplied to the antenna, and the phase difference between voltage and current. To evaluate the method the plasma density obtained by the method is compared to the plasma density taken by a Langmuir probe at the center of reactor.