Authors: K Ito S Tsukimoto T Kabe K Tada M Murakami
Publish Date: 2007/04/10
Volume: 36, Issue: 5, Pages: 606-613
Abstract
In our previous studies thin Tirich layers were found to uniformly cover SiO2/Si substrate surfaces at the interface with CuTi alloy films after annealing at elevated temperature These Tirich layers were also found to prevent intermixing between the CuTi alloy films and the substrate resulting in a simple barrier formation technique called “selfformation of the diffusion barrier” which is attractive for fabrication of ultralarge scale integrated ULSI interconnect structures In the present study to understand the mechanism of selfformation of the Tirich barrier layers on the substrate surface the effects of SiO2/Si SiN/SiO2/Si and NaCl substrate materials on the interfacial microstructure were investigated The microstructures were analyzed by transmission electron microscopy TEM and secondary ion mass spectrometry SIMS and correlated with the electrical properties of the CuTi interconnects It was concluded that the chemical reaction of Ti with the substrate materials was essential for the selfformation of the Tirich layersThis work was supported by GrantsinAid for Scientific Research from The Ministry of Education Culture Sports Science and Technology Grant No 18360324 and the Nanotechnology Program on Cu Thin Films of the New Energy and Industrial Technology Development Organization NEDO of Japan
Keywords: