End-pointing chamber clean by calorimetric probing of process effluent

The semiconductor industry employs gas-phase cleaning widely to remove materials deposited on the chamber walls during thin-film deposition processes. Chamber clean end-pointing—i.e., terminating the process when the chamber is clean—is desirable to manage cost of ownership and environmental impact. Existing end-pointing methods tend to rely on changes of plasma characteristics as the in situ plasma removes the deposit in time. Chamber clean technology is moving towards remote generation of plasma species for cleaning. In this arrangement, the chamber is located downstream from the plasma source. Because the etching reaction occurs ex situ, there are no relevant changes occurring in the plasma characteristics, and the effectiveness of many existing methods decreases. We report the development of a calorimetric probe for chamber clean end-pointing. The probe has an all solid-state construction and is engineered to be immersed in the process effluent during end-pointing operation. When the probe is operated...