Earlier blog #428 was concerned with UV (185 nm and 254 nm) cleaning used in semiconductor processing for the purpose of organic contaminants removal from the processed surfaces. As we all know now, UV light (especially far-UVC, 222 nm) is used for disinfection which basically comes down to the annihilation of organic “contaminants” (if the use of the term “contaminants” in reference to viruses and bacteria is appropriate).

The problem with UV is that it needs to be used (wavelengths selection) very carefully because either through ozone generation or direct exposure it can be very harmful to us.  On the other hand, oxygen plasma, which is even more effective than UV in organic contaminants removal, cannot be easily implement not in the reduced pressure environment.

An easy to carry out alternative to UV irradiation is the use of much longer wavelength infrared lamps and use heat generated by such lamps (halogen for instance) to remove organics from the solid surfaces in ambient air. It is well known that heat kills viruses and bacteria. Just like in the case of UV cleaning, such IR lamp cleaning was shown very effective in semiconductor processing (e.g. A. Danel, C. L. Tsai, K. Shanmugasundaram, F. Tardif, E. Kamieniecki, J. Ruzyllo, “Cleaning of Si Surfaces by Lamp Illumination”,  UCPSS 2002, Solid State Phenomena, vol. 92, 196-198 (2002)). When properly implemented (temperature, time of exposure) it is also effective in neutralizing viruses and bacteria.

Yet another example how the high demands and experiences of semiconductor processing can be employed in our daily lives…