Wireless wafer-type probe system for measurement of two-dimensional plasma parameters and spatial uniformity

Abstract

A wireless wafer-type probe system was developed to measure two-dimensional plasma parameters and uniformity. The apparatus uses double probe theory with a harmonic detection method. The plasma parameters, such as the electron temperature, ion density and ion flux, are derived by using the amplitudes of the first and third harmonic currents. The experiment was conducted in an inductively coupled plasma. The measurements of the wireless wafer-type probe were compared with a floating-type Langmuir probe and a similar trend was observed. As the inner and outer antenna current ratio changes, the wireless wafer-type probe was able to measure the evolution of the two-dimensional ion density profiles. Since the wireless wafer-type probe system was electrically isolated and designed to operate stand-alone in the chamber, it can be installed in plasma chambers without any external controllers. This plasma diagnostic system shows promise for processing plasmas.