• Den Toonder, Jaap M. J.
• Zhang, G. Q.
• Van, A. R. Dijken
• Ramone, Y.
• Beijer, J. G. J.

Abstract

SiLK is a polymer material developed for use as a thin-film dielectric in the interconnect structure of high-density integrated circuits. Among others, its thermomechanical properties play a dominant role for the integrity and reliability of the interconnect during processing, testing, and use. Being a polymer, SiLK may show viscoelastic (time-dependent) behavior. In this paper, we use nanoindentation techniques in combination with analytical and finite element modeling (FEM) to determine the viscoelastic properties of a thin SiLK film on a silicon substrate. Indentation-creep experiments show that this SiLK film indeed responds in a viscoelastic way. This may be caused by the non fully cross-linked test samples prepared using nonstandard processing. Using the FEM simulation, we find that the behavior of this thin SiLK film can be described with a linear viscoelastic model up to the characteristic stress and strain levels of approximately 200MPa and 3%, respectively. For higher stress and strain levels, the response becomes nonlinear. The results are validated with independent indentation load-unload measurements.

Topics

• density
• impedance spectroscopy
• polymer
• experiment
• simulation
• nanoindentation
• Silicon
• creep