Formation of Ti-Si-N film using low frequency, high density inductively coupled plasma process

Abstract

Titanium silicon nitride (Ti–Si–N) has emerged as a strong candidate for next generation diffusion barrier material in copper/low-k dielectric back-end-of-line device fabrication. Low frequency, high density inductively coupled plasma process has been developed for the growth of Ti–Si–N film. This work employs the reaction between TixSiy and the nitrogen plasma. Ti–Si–N films have been successfully grown over different process conditions. Film properties were characterized by Rutherford backscattering spectrometry (RBS), x-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy, x-ray diffraction (XRD), and four-point resistivity probe. RBS reveals that 2–67 at. % of nitrogen can be achieved through the implantation of nitrogen in TixSiy film. XPS and XRD results show that TiN and Si3N4 are successfully formed. As the external bias increases from 100 to 300 V, there is an 80% increase in sheet resistance. Other process conditions investigated do not show a significant effect on film sheet resistance. Increasing argon plasma activation time can significantly increase the implantation depth of nitrogen into TixSiy

substrate.