Patent ID: 8545669

Claim:
A method of measuring plasma properties in a plasma processing system, comprising: a) providing a plasma processing system having a plasma chamber; b) providing a sensor array comprising a plurality of electrically floating sensors disposed within the plasma chamber, wherein each sensor includes first and second conductive pads; c) generating a plasma within the plasma chamber for use in a plasma process; d) collecting a plurality of measurements related to bulk properties of the plasma using the plurality of electrically floating sensors in sensor array by applying a voltage pulse to each sensor and measuring a current with each sensor; e) analyzing a matrix constructed from the plurality of measurements, wherein the matrix includes a plurality of diagonal terms I(i,i) and off-diagonal terms I(i,j), wherein each diagonal term I(i,i) represents a current measured between the first and second pads within a sensor in the array, and wherein each off-diagonal term I(i,j) represents a current obtained by passive current measurement at a given sensor (i) due to active pulsing of a different sensor (j); and f) determining one or more bulk properties of the plasma from the off-diagonal terms I(i,j) of the matrix, wherein the bulk properties include a bulk conductance of the plasma.