Effects of N2O plasma treatment on perhydropolysilazane spin-on-dielectrics for inter-layer-dielectric applications

•Perhydropolysilazane (PHPS) layer is evaluated as a Si interlayer dielectric.•Examine effects of the N2O plasma treatment (PT) on PHPS spin-on-dielectrics (SODs)•Significantly improved metal contact resistances are achieved using the N2O PT.•Contact resistance enhancement by PT is due to the minimized carbon contamination.

Effects of the N2O plasma treatment (PT) on perhydropolysilazane spin-on-dielectric (PHPS SOD) were examined as potential inter-layer-dielectrics (ILDs) for sub-30 nm Si circuits. The spin-coated PHPS (18.5 wt.%) ILD layers converted at 650 °C were integrated with the 0.18 μm Si front-end-of-the line process. A modified contact pre-cleaning scheme using N2O PT produced more uniform and stable contact chain resistances from the SOD ILDs than the case of pre-cleaning only by buffered oxide etcher. Our analysis shows that this enhancement is due to the minimized carbon contamination on the PHPS side-wall surface densified by PT.