Sj. Ding et al., XPS characterization of the interface between low dielectric constant amorphous fluoropolymer film and evaporation-deposited aluminum, APPL SURF S, 178(1-4), 2001, pp. 140-148
The interaction of low dielectric constant amorphous fluoropolymer (AF) fil
m with evaporation-deposited aluminum has been investigated via high-resolu
tion X-ray photoelectron spectroscopy (XPS). For the sake of gaining the in
terface of the AV AF sample, the partial aluminum has been removed by Ar io
n etching. In situ XPS measurements show that Al fluoride, C-O-Al and Al ca
rbide are formed at the interface between aluminum and AE The formation of
Al fluoride results mainly from a reaction between Al atom and F free radic
als due to the breakage of one C-F bond in CF3 groups, meanwhile, this also
leads to an increase in CF2 groups. After annealing, the relative content
of C-F bonds at the interface decreases remarkably, and the relative concen
trations of C-O-Al and Al-C complexes increase evidently. However, the rela
tive percentage of Al fluoride decreases, indicating that Al fluoride has h
igher fluidity than the C-O-Al and AI-C complexes against annealing. Moreov
er, the relative percentages of the elements at the interface show that the
annealing causes a little diffusion of Al into the AF film. Possible react
ion mechanisms of Al with AF are also discussed. (C) 2001 Published by Else
vier Science B.V.