Properties of electroplated copper thin film and its interfacial reactionsin the EPCu/IMPCu/IMPTaN/SiO2/Si multilayer structure

The properties of electroplated copper (Cu) film on a thin seed layer of io nized metal plasma deposited Cu have been investigated as a function of ann ealing temperatures together with the diffusion barrier performance in the EPCu/IMPCu/IMP-TaN/SiO2/Si multi-layer structure. The growth morphology of electroplated Cu film on ionized metal plasma deposited Cu seed layer was f ound to be more uniform and gave lower root mean square values(similar to 1 3.76 nm), resulting in a lower resistivity (1.72 mu Omega cm) of electropla ted Cu film. Annealing at temperatures of higher than 750 degreesC resulted in slightly higher sheet resistance? larger grain sizes and rougher surfac e. Scanning Electron Microscopy images showed that the agglomeration of ele ctroplated Cu film occurred only at annealing temperatures higher than 850 degreesC. During annealing, the electroplated Cu grains grew normally and t heir sizes increased to about five times larger than the thickness of the e lectroplated Cu film but the (111) preferred orientation was maintained up to 950 degreesC. Furthermore, the interfacial reactions between Cu film lay er and ionized metal plasma deposited Tantalum nitride (TaN) diffusion barr ier were also detected at annealing temperatures of higher than 750 degrees C. (C) 2001 Elsevier Science B.V. All rights reserved.