Patent ID: 8847159
Filing Date: 2014-09-30
Classification: H01J,H05H,Y10T

Abstract:
1. An ion energy analyzer for use in determining an ion energy distribution of a plasma, comprising: an entrance grid forming a first surface of the ion energy analyzer positioned as to be exposed to the plasma when the analyzer is positioned in a plasma processing apparatus, the entrance grid including a first plurality of openings, each of the openings of the first plurality having a dimension that is less than a Debye length for the plasma such that a plasma sheath at a boundary of the plasma remains relatively unperturbed and the plasma sheath does not penetrate openings of the first plurality; an ion collector forming a second surface of the ion energy analyzer; a first voltage source operably coupled to the ion collector and configured to bias the ion collector relative to the entrance grid; a selection grid positioned between the entrance grid and the ion collector and including a second plurality of openings; a second voltage source operably coupled to the selection grid and configured to selectively and variably bias the selection grid; an ion current meter operably coupled to the ion collector and configured to measure an ion flux onto the ion collector and transmit a signal representing the measured ion flux; a first insulator positioned between the entrance grid and the selection grid and configured to electrically isolate the entrance grid from the selection grid and reduce or prevent electrical breakdown therebetween, wherein a geometry of the first insulator is selected to project inwardly from each respective channel such that no straight line path exists between any two points on the entrance grid and the selection grid, respectively, from a set of all possible paths extending along a surface of the first insulator; and a second insulator positioned between the selection grid and the ion collector and configured to electrically isolate the selection grid from the ion collector and reduce or prevent electrical breakdown therebetween, wherein a geometry of the second insulator is selected to project inwardly from each respective channel such that no straight line path exists between any two points on the selection grid and the ion collector, respectively, from a set of all possible paths extending along a surface of the second insulator.