Void-free filling of spin-on dielectric in 22nm wide ultrahigh aspect ratio Si trenches

Abstract

The authors demonstrate fabrication of ultrahigh aspect ratio nanotrenches, made by nanoimprint lithography and dimension reduction, as test bed shallow trench isolation structures for the 22nm semiconductor node. Polysilazane based spin-on dielectric (SOD) material is spin coated into the nanotrenches, of 22nm width and aspect ratio over 30, to evaluate gap filling property. Fourier transform infrared spectroscopy analysis is used to characterize the curing properties of the SOD, showing that the material can be cured in oxygen at temperatures of 600°C and higher. Transmission electron microscopy images indicate that the filling is complete and void-free along the entirety of the trench.