Sensor array for measuring plasma characteristics in plasma processing environments
First Claim
1. 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.
5 Assignments
0 Petitions
Accused Products
Abstract
A plasma processing system is provided with diagnostic apparatus for making in-situ measurements of plasma properties. The diagnostic apparatus generally comprises a non-invasive sensor array disposed within a plasma processing chamber, an electrical circuit for stimulating the sensors, and means for recording and communicating sensor measurements for monitoring or control of the plasma process. In one form, the sensors are dynamically pulsed dual floating Langmuir probes that measure incident charged particle currents and electron temperatures in proximity to the plasma boundary or boundaries within the processing system. The plasma measurements may be used to monitor the condition of the processing plasma or furnished to a process system controller for use in controlling the plasma process.
-
Citations
26 Claims
-
1. 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
-
-
14. A system for measuring plasma properties in a plasma processing system, comprising:
-
a) a sensor array disposed about a boundary of a processing region of a plasma processing system, the sensor array comprising a plurality of electrically floating sensors, wherein each sensor includes first and second conductive pads; b) a circuit for stimulating the plurality of sensors in the sensor array to collect a plurality of measurements related to properties of a processing plasma within the plasma chamber by applying a voltage pulse to each sensor and measuring a current with each sensor; and c) a processor coupled to the sensor array, wherein the processor is configured to analyze a matrix constructed from the plurality of measurements and determine one or more bulk properties of the processing plasma from a plurality of diagonal terms I(i,i) and off-diagonal terms I(i,j) of the matrix, 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 wherein the one or more bulk properties include a bulk conductance of the plasma. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
-
Specification