Measurement of Diffusion Coefficients of Copper in TiNX Diffusion Barriers

• Main Authors: Jyun-Yuan Chen, 陳俊元
• Other Authors: Chiapyng Lee
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/39709956202720125159

碩士 === 國立臺灣科技大學 === 材料科技研究所 === 93 === The study is to evalucate the obstruction of Cu in TiNx films deposited by RF magnetron-sputtering system. The grain size, crystal structure, crystal arrangement, chemical composition and other terms for TiNx films deposited by RF magnetron-sputtering system were analyzed. Before and after annealing, behavior for Cu/TiNx/Si multilayered sample were investigated by HRTEM and other instruments. By combining all analysis with measurement of diffusion coefficients of copper in TiNx diffusion barriers, examining the Nitrogen quantity and TiNx thickness were how to affect diffusion ability of Cu into the Si substrate. The experimental results indicate that the crystalline structure of TiNx film is changed from Hexagonal metal Ti to stable rock-salt TiN structure with the raise of Nitrogen quantity. And microcrystalline is from the column to nanocrystalline structure with more Nitrogen quantity. Having sufficient energy（After annealing of high temperatrure）, the nanocrystalline structure is back to column structure. We can find out that barrier failure was due to Cu atoms diffusing in Cu/TiNx/Si multilayered sample. The failure time （threshold time）of TiNx films was estimated from the sheet resistance profiles by FPP. That failure time combining with formula L（the average diffusion length of atoms）= 2(Dt)1/2 would get diffusion coefficients of copper in TiNx diffusion barriers. HRTEM shows the boundary length would be more than barrier thickness in thin barrier films, so that diffusion coefficients of copper in TiNx diffusion barriers were dropped . In ULSI, the advantage of using thinner TiNx barrier include to reduce resistivity of diffusion barrier and diffusion coefficient of copper in TiNx diffusion barrier.