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Kowal, Jan; Rogers, Tony; Nixon, Tony and Aitken, Nicholas
(2006).
DOI: https://doi.org/10.1149/MA2005-01/11/513
Abstract
UV radiation is already routinely applied to the cleaning of semiconductor wafers, where the main effect is the chemical removal of surface contaminants by the action of activated oxygen atoms. UV treatment of wafers prior to fusion bonding has shown a dose-dependent effect [1], where an improvement in bond strength is obtained after short exposure to radiation from a low-pressure Hg discharge. Further exposure results in a diminished benefit. It has been suggested that prolonged exposure cause dehydration of the surface and a reduced surface reactivity. Alternatively, there may be a surface roughening effect, but no mechanism for this has been proposed.
Samples of semiconductor standard <100> p-type silicon were subjected to radiation (mainly at 254 nm, with a lower peak at 185 nm) from a low-pressure Hg source placed inside the vacuum chamber of a Kratos XPS system. Exposure to the shorter wavelength was prevented for some samples by means of a filter. Spectra of the abundances of surface species were obtained, without breaking vacuum, as a function both of total radiation dose and spectral composition. These surface chemistry data are compared with bond strengths obtained for whole wafer samples subjected to equal exposures of UV radiation.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)
