The UVO method is a photo-sensitized oxidation process in which the contaminant molecules of photo resists, resins, human skin oils, cleaning solvent residues, silicone oils, and flux are excited and/or dissociated by the absorption of short-wavelength UV radiation.
Atomic oxygen is simultaneously generated when molecular oxygen is dissociated by 184.9 nm and ozone by 253.7 nm uv. The 253.7 nm UV radiation is absorbed by most hydrocarbons and also by ozone.
The products of this excitation of contaminant molecules react with atomic oxygen to form simpler, volatile molecules which desorbs from the surface.
Therefore, when both UV wavelengths are present atomic oxygen is continuously generated, and ozone is continually formed and destroyed.
By placing properly pre-cleaned samples within five millimeters of ozone producing UV source, such as the low pressure mercury vapor lamp in the UVO-Cleaner , near atomically clean surfaces can be achieved in less than one minute. The process does not damage sensitive device structures.