One of the potential benefits of Meaglow’s hollow cathode plasma technology is scalability. In a recent news article from June 2019, we mentioned that Meaglow was breaking the old paradigm of high density but small area legacy plasma sources, for which delivery to larger areas dilutes the active plasma species. The question has to be asked, why can’t a high density plasma source be the same size as the substrate? And the answer is, with a hollow cathode source it can.
Meaglow had already developed designs for 4″ and 8″ diameter hollow cathode sources for high radical flux delivery over a similar area during plasma assisted atomic layer deposition. Now those designs have been refined in a 12″ plasma source, the first of which has now been shipped to a customer in the semiconductor deposition equipment market. The cathode, shown above before cleaning, was all aluminum for compatibility with silicon processing. The current design has been tested for operation over a pressure range from 80 mTorr to 8 Torr, though other pressure ranges can be achieved through custom design, and lower pressure operation with this current source may also be possible.
Shown below, left, is the plasma source in our test chamber with nitrogen at only 100 watts of RF power, though the source is designed for operation up to 3 kilowatts. On the right is the plasma source itself.