Method and apparatus for diagnosing status of parts in real time in plasma processing equipment
Apparatus and methods for diagnosing status of a consumable part of a plasma reaction chamber, the consumable part including at least one conductive element embedded therein. The method includes the steps of: coupling the conductive element to a power supply so that a bias potential relative to the ground is applied to the conductive element; exposing the consumable part to plasma erosion until the conductive element draws a current from the plasma upon exposure of the conductive element to the plasma; measuring the current; and evaluating a degree of erosion of the consumable part due to the plasma based on the measured current.
1. A consumable part of a plasma reaction chamber, the consumable part including a surface to be exposed to plasma, comprising:
conductive elements embedded in the consumable part and electrically coupled to each other;
a probe circuit coupled to the conductive elements; and
a power supply coupled to the probe circuit and ground to apply a bias potential to the conductive elements relative to the ground,
wherein the conductive elements are operative to draw a current from the plasma upon exposure of the conductive elements to the plasma and the probe circuit is operative to measure the current, wherein the consumable part is an electrode for generating plasma or a dielectric material selected from the group of edge ring and confinement ring.
2. The consumable part of claim 1 , wherein the power supply is a DC power source.
3. The consumable part of claim 1 , wherein the probe circuit includes a resistor and a voltmeter to measure an electrical potential across the resistor.
4. The consumable part of claim 3 , wherein the voltmeter is connected to the resistor in parallel.
5. The consumable part of claim 1 , wherein each of the conductive elements has a shape selected from the group consisting of pin, polygonal, circular, and annular.
6. The consumable part of claim 1 , wherein the conductive elements are electrically connected to each other by a conductive wire.
7. The consumable part of claim 1 , wherein the consumable part is formed of conductive material and the conductive elements are embedded in the consumable part and electrically insulated from the consumable part by a dielectric layer.
8. A method of processing a semiconductor substrate in a plasma reaction chamber including the consumable part of claim 1 , comprising plasma processing the semiconductor substrate.
9. The consumable part of claim 1 , wherein the power supply is operable to supply a bias potential of 10 to 15 volts relative to the ground to the conductive elements.
10. The consumable part of claim 1 , wherein the power supply is connected in series to the probe circuit.
11. The consumable part of claim 1 , wherein the conductive elements are embedded at a depth corresponding to a diagnostic event.
12. The consumable part of claim 11 , wherein the diagnostic event is end of useful lifetime of the consumable part.
13. The consumable part of claim 1 , wherein the conductive elements are annular conductive elements embedded in the consumable part.