| Summary: | 碩士 === 國立中興大學 === 材料科學與工程學系所 === 99 === As the line width and spacing of Ultra-Large Scale Integrated (ULSI) circuits continually decrease, copper has been widely used as an interconnect material because of its low electrical resistivity and high electromigration resistance. To retard rapid copper diffusion in interconnect structures, an effective diffusion barrier layer with high thermal stability, low electrical resistivity and good interface adhesion is demanded. In this study, an AlCrTaTiZrRu senary high-entropy alloy (SHEA) and its nitride (SHEAN) films were deposited by reactive radio-frequency magnetron sputtering in an Ar+N2 mixed atmosphere. The N2 flow ratio (N2/(Ar+N2)) was set as 0% and 30% to obtain SHEA (0% N) and SHEAN0.5 (each element content was around 11 %, and the N content was about 32.2%. The N-to-HEA ratio was around 0.5) films. The Barrier properties of SHEAN0.5/SHEA bilayer (BL, 1.5 nm/1.5 nm) and SHEAN0.5/SHEA/SHEAN0.5/SHEA quadru-layer (QL, each layer 0.75 nm) structures to retard Cu diffusion were investigated under annealing at 700℃to 900℃. From the analyses of diffusion behaviors, it was found that the electrical resistance of Si/BL/Cu and Si/QL/Cu film stacks remained at a low level after annealing at 800℃, implying the good diffusion resistance of the BL and QL barriers. At the temperature up to 900℃, a Cu3Si crystalline phase appeared, and the electrical resistance obviously increased, indicating the failure of the BL and QL as diffusion barriers.
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