Fluorinated polyimides for interlayer dielectric applications: Tailoring of properties via copolymerization (original) (raw)

1996

Abstract

Over the past several years DuPont has been exploring new, rod-like fluorinated polyimides for interlayer dielectric (ILD) applications. It has been shown that copolymerization is a versatile method for tailoring properties of these rigid polyimides. Initial product offerings from DuPont showed an excellent balance of properties for ILD applications. These materials, however, due to their highly rod-like structure and very low in-plane coefficient of thermal expansion (CTE), actually yielded negative thermal stresses on silicon at the 1 {mu}m thicknesses typical of interlayer dielectrics. More flexible materials with higher CTE typically yield positive stress values which can be undesirably quite high. The dielectric constant of these highly rod-like fluorinated polyimides was also somewhat anisotropic, again due to the rod-like nature and resulting high in-plane orientation of these polyimides. Since a thermal stress on silicon near zero and a more isotropic dielectric constant are likely the most desirable states for an ILD, the highly rod-like polyimide was further optimized by incorporation of a more flexible fluorinated comonomer, 6FDA, at various levels to increase CTE and balance dielectric constant. The various properties of this series of fluorinated polyimides were investigated. The results have shown that it is indeed possible to obtain near zeromore » stress on silicon while attaining more isotropic dielectric constant via structure optimization.« less

Jim Leu hasn't uploaded this paper.

Let Jim know you want this paper to be uploaded.

Ask for this paper to be uploaded.