Using the Readback Plot to Detect the Presence of RF Voltage and Current

Issue

The Readback plot can be a valuable tool to gather data points when troubleshooting an issue. In the example listed in this article, we will view the RF Supply Voltage and Current to help further troubleshoot a plasma ignition issue.

Environment

• iCAP Q
• iCAP RQ
• iCAP TQ
• ECCN:EAR99

Resolution

First it will be helpful to know if any RF voltage is being outputted from the Power Supply. This can be done as follows:

1.    Click on Readback Plot

2.    Change the HardwareObjectList in the dropdown menu to BrigidInstCtrl and then tick the two checkboxes for the parameters: RF Supply Voltage Set and RF Supply Voltage Readback as shown below

3.    Attempt to ignite the plasma by clicking the  button

 

4.    Right-click anywhere in the graph area, click Export data and then email the CSV file to technical support

Note: Another option would be to take a snippet of the graph area and legend

 

If the RF Supply Voltage Readback is staying at zero, it is possible that the RF Power Supply has “latched” which is preventing the voltage from being output. To try and troubleshoot this, switch off the power to the instrument for 5-10 minutes and then turn it back on. A lengthy time is required in order to ensure that the power supply has fully deenergized. After power cycling the instrument for 5-10 minutes, attempt to ignite the plasma. If it ignites and stays lit, problem solved. If not, continue on with the next steps.

 

If the RF voltage is present now but the plasma still does not ignite, it will be helpful to observe if the RF voltage and current are present or not. This can be done as follows:

 

5.    Click on Readback Plot

 

6.    Change the HardwareObjectList in the dropdown menu to BrigidInstCtrl and then tick the two checkboxes for the parameters: RF Supply Voltage Readback and RF Generator Supply Current Readback as shown below

 

7.    Attempt to ignite the plasma by clicking the  button

 

8.    Right-click anywhere in the graph area, click Export data and then email the CSV file to technical support

Note: Another option would be to take a snippet of the graph area and legend

 

 

Analysis

If the plasma won’t light, it is helpful to discern if any voltage and current is present in the RF circuit. This troubleshooting exercise will especially be helpful if the following text is present in the log file which means that the plasma is attempting to ignite but has not been successful in doing so.

Ready to light plasma.

Failed to ignite plasma count: 1

Waiting for RF generator to become ready for ignition.

Ready to light plasma.

Failed to ignite plasma count: 2

Ready to light plasma.

Failed to ignite plasma count: 3

Plasma could not be lit.