The polyimide (PMDA/ODA) titanium interface: An experimental and theoretical study
- IBM-France, Laboratoire d`Etude des Surfaces et des Structures, Service 1807/31U, 224 Bd J. Kennedy, 91105 Corbeil Essonnes Cedex (France)
- Universite Paris 7-Denis Diderot, Institut de Topologie et de Dynamique des Systemes, 1 rue Guy de la Brosse, 75005-Paris (France)
- Universite de Marne la Vallee, 2 Allee Jean Renoir, 93166 Noisy-le-Grand Cedex (France)
The interface between evaporated Ti and PMDA/ODA polyimide is examined using several techniques. The formation of small TiO{sub 2} particles at this interface (15 to 40 {mu}m diameter, ca.30 nm thickness, covering about 6{percent} of the interfacial area) is demonstrated. The failure is of cohesive type in the polymer layer. When the residual pressure during Ti evaporation is increased, the number of TiO{sub 2} particles increases, adhesion of the Ti layer is lowered and the locus of failure is closer to the metal layer. When an oxygen plasma treatment is performed onto PMDA/ODA prior to Ti evaporation, the failure mode remains cohesive in the polymer layer. However the failure occurs at the modified/unmodified polymer limit. {ital Ab} {ital initio} (SCF) calculations were finally performed on models of the PMDA-ODA polyimide in interaction with one Ti atom, in order to determine the most favorable interaction sites of this metal with the polymer. The most favorable interaction corresponds to the formation of a complex between Ti and the aromatic ring of the PMDA unit. Other possible sites of interaction are, in decreasing order of stability: the heterocycle of PMDA, the {approx_gt}C=O groups of PMDA and the ODA aromatic ring. Calculations of the core MO energies for the various model situations, show that it is not possible to account for the low energy C1s peak observed at ca.282 eV. Introduction in the model of a Ti atom bonded to one of the aromatic carbons permits to account for this peak. Thus, the existence of Ti-C bonds in the polyimide-Ti system is clearly confirmed. {copyright} {ital 1996 American Institute of Physics.}
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 286454
- Report Number(s):
- CONF-950119--
- Journal Information:
- AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 354; ISSN APCPCS; ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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