Static SIMS investigation of metal/polymer interfaces

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Abstract
The formation of the interface between thermally evaporated metals (aluminium, copper) and polymers [poly(ethylene terephthalate) (PET), poly(methyl methacrylate) (PMMA)] has been investigated by static SIMS. Two generations of instrument have been used. The first one, using a quadrupole mass spectrometer directly connected to the same ultrahigh vacuum environment as the metallization chamber, has allowed an in situ characterization of the interface formation after each metal deposition in the submonolayer regime. The second system, using a time‐of‐flight (ToF) mass spectrometer, has allowed ex situ analyses of Al/PET, Cu/PET, Al/PMMA and Cu/PMMA interfaces. The high mass resolution of the ToF spectrometer led to the unambiguous identification of the molecular fragments that are characteristic of polymer–metal interaction. The results show that Al atoms react with the oxygenated parts of PET and PMMA. This interaction limits the lateral diffusion of Al atoms on the polymer surface and, consequently, induces a two‐dimensional growth of the Al film on these polymer substrates. In the Cu deposition case, a weaker metal–polymer interaction is observed. This leads to Cu clustering and a three‐dimensional growth. Time‐of‐flight SIMS molecular imaging clearly reveals Cu clusters on the PMMA surface.