COPPER-DIFFUSION-RESISTANCE TREATMENT BY NH_3 PLASMA FOR ORGANIC LOW-K METHYLSILSESQUIOXANE/COPPER INTERFACE

摘要

The requirement for the integration of copper and low dielectric constant materials has been proposed to reduce the RC delay of interconnects for ULSI technology. An organic polymer, Methylsilsesquioxane (MSQ), has been synthesized for application as a spin-on dielectric material in the multilevel interconnection structure. With MSQ, a low value of dielectric constant can be achieved because of its lower film density compared to thermal oxide and substitution of Si-CH_3 group for highly polarized Si-O group. In this work, we have investigated the interaction between copper and MSQ film. Experimental results show that copper diffusion in MSQ film would not occur until the annealing temperature up to 450 C. In addition, the NH_3 plasma treatment was applied on MSQ film to enhance the resistance of MSQ film to Cu diffusion. Dielectric constant of NH_3 treated MSQ film can be maintained at a stable constant after a annealing treatment from 400 to 550 C.