Method of cleaning a plasma processing device

A method of cleaning a plasma processing device, comprising the steps of:

• creating a plasma within a remote plasma source which is separated from a process section of the device including a process chamber having a main body delimiting a process space in which plasma processing is carried out by the device and a conduit leading from the process space to a pump for exhausting gas from the process space, the plasma comprising radicals and ions;
• cleaning the process chamber with the radicals created in the remote plasma source by allowing the radicals to enter the process chamber from the remote plasma source while preventing a majority of the ions created in the remote plasma source from entering the process chamber and without producing charged particles anywhere in the process chamber;
• detecting a DC bias developed on a component of the process section during the cleaning;
• and
• using the detected DC bias to determine an end-point of the cleaning and, on determination of the end-point, to stop the cleaning.

A method of cleaning a process chamber of a plasma processing device, comprising the steps of:

• creating a plasma within a remote plasma source which is separated from the process chamber, the plasma comprising radicals and ions;
• cleaning the process chamber with the radicals created in the remote plasma source by allowing the radicals to enter the process chamber from the remote plasma source while preventing a majority of the ions created in the remote plasma source from entering the process chamber;
• detecting a DC bias developed on a component of the plasma processing device during the cleaning;
• and
• using the detected DC bias to determine an end-point of the cleaning and, on determination of the end-point, to stop the cleaning,
• wherein the plasma is created by introducing source gas into the remote plasma source and exciting the source gas, and
• the cleaning of the process chamber and the detecting of the DC bias are carried out without exciting gas to produce a plasma anywhere else in the plasma processing device but in the remote plasma source.