New Aspects of Nano-meter Structures of Porous Low-k Films and Their Impacts on Cu/Low-k Processes for 65 nm and Beyond TEM Tells What?

Nano-meter order structures of porous low-k films have been successfully characterized by a transmission electron microscopy (TEM). Two proposed applications will be presented in this paper. Using a TEM tomographic technique, 3-dimensional structures of pores in porous low-k films have been quantitatively evaluated and it was shown how the pore structures influenced on materials penetration phenomena into the porous structures. A valence electron energy loss spectroscopy (V-EELS) combined with a scanning TEM (STEM) clearly showed distributions or change of dielectric constants in the porous low-k trench structures with nm-order spatial resolution induced by plasma processes such as dry etch and ash with or without change in composition.