Methods for calibrating an optical emission spectrometer

A method for calibrating an optical emission spectrometer (OES), comprising:

• mounting a light fixture within a process chamber, wherein the light fixture includes a light source;
• measuring an optical intensity of radiation from the light source with an OES located outside the process chamber at a first time;
• removing the light fixture from the process chamber after measuring the optical intensity of radiation at the first time;
• performing a deposition of a semiconductor substrate after measuring the optical intensity of radiation at the first time;
• re-mounting the light fixture within the process chamber;
• measuring an optical intensity of radiation from the light source with the OES located outside the process chamber at a second time;
• comparing the optical intensity of radiation at the first time with the optical intensity of radiation at the second time;
• and
• modifying the OES if the optical intensity of radiation at the first time is different than the optical intensity of radiation at the second time.

A process system, comprising:

• a process chamber;
• a plate mounted within the process chamber;
• an optical emission spectrometer (OES) located outside the process chamber;
• a light fixture mounted to the plate, wherein the light fixture includes a light source;
• wherein:
• an optical path is provided between the light source and the OES, and wherein the OES measures an optical intensity of radiation from the light source;
• and
• a computer-readable storage medium configured to receive information from the OES, and when executed by a processor performs an operation, comprising:
• comparing the optical intensity of radiation at a first time with the optical intensity of radiation at a second time;
• and
• modifying the OES if the optical intensity of radiation at the first time is different than the optical intensity of radiation at the second time.