XEI Scientific reports novel approach to removing silicone-based contamination

ERJ staff report (TP)

Redwood City, California − XEI Scientific announced the publication of a paper in collaboration with General Electric's Global Research Center on the use of in-situ plasma cleaning. The paper appears in the Journal of Vacuum Science & Technology A, reported Nanotechnology Now

The press release said: “Contamination, even at extremely low levels, can often hide or distort analyses of surfaces that researchers would like to study. Such is the case of many of the samples analysed at General Electric's Global Research Center in New York. Attempts to study ‘as received’ samples by time of flight secondary ion mass spectrometry (ToF-SIMS) reveal a contamination signature that has come from processing, handling and/or a specific exposure.

“ToF-SIMS provides high surface specificity so that contamination by hydrocarbons and/or silicones may actually mask the surface features of interest, which may inhibit or compromise accurate analysis. While use of remote plasmas to mitigate hydrocarbon contamination is established technology, this paper represents the first demonstration that silicones (in this case, polydimethylsiloxame) can be removed as well.”

In the paper, "In-situ plasma cleaning of samples to remove hydrocarbon and/or polydimethylsiloxame prior to ToF-SIMS analysis1", lead author Vincent Smentkowski reports on the use of an Evactron air-based remote plasma for cleaning of samples.

The press release added: “This approach is preferred to sputter cleaning as the latter often changes the chemistry on the surface under analysis. Here, samples were cleaned in the load lock of a commercially available ToF-SIMS instrument immediately prior to analysis. The experimental observations show that the Evactron system produces no ion beam effects (sputtering) with even extended exposure, thus showing minimal artifacts from material removal and ion bombardment. This advantage results from the design of the Evactron RF plasma cleaner which minimises ion formation and downstream sputtering, allowing radical species to dominate the cleaning process.

“It is interesting to note that plasmas generated using ambient air result in surface oxidation and this is often beneficial through the increase in sensitivity of ToF-SIMS where the ion yield of many elements is enhanced. This paper demonstrates the potential for the use of plasma cleaning not only for basic analyses but in a production environment as well.”

XEI Scientific was founded in 1991 and is based in Redwood City, California.

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