Molecular design of POSS core star polyimides as a route to low- κ dielectric materials

• Published in: Materials chemistry and physics 2008-12, Vol.112 (3), p.1040-1046
• Main Authors: Seckin, Turgay, Koytepe, Suleyman, Adiguzel, H Ibrahim
• Format: Article
• Language: English
• Subjects: Chemical synthesis; Dielectric properties; Electron microscopy; Inorganic compounds
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2008.07.017

Star polyimides incorporating the polyhedralsilsesquioxane (POSS-NH 2) unit were prepared by in situ curing of polyamic acid macromolecules with amino POSS, for the molecular-level design of low dielectric constant (low-κ) materials that can be used to manufacture integrated circuits. ▪ Star polyimides incorporating the polyhedralsilsesquioxane (POSS-NH 2) unit were prepared by in situ curing of polyamic acid macromolecules with amino POSS, octa (aminopropylsilsesquioxane), for the molecular-level design of low dielectric constant (low- κ) materials that can be used to manufacture integrated circuits. Octameric POSS-NH 2 having restricted rotation by multiple point attachment to the polyimide backbone is shown to introduce free volume into the films, thereby lowering their dielectric constants. A process for synthesizing POSS-polyimide star nanocomposites is reported, comprising a step forming porous-type POSS and subsequent step with polyimide precursor. The POSS-NH 2 containing polyimides exhibit a number of desirable properties including low-water absorption and high thermal stability. Systematic studies demonstrate that proper insertion of POSS into a polyimide backbone can give rise to a reduction in the material's dielectric constant while also improving its mechanical and thermal properties.