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MICHAEL PAVLOV, PETER BRATIN & GENE CHALYT, ECI Technology, East Rutherford, NJ, USA

ABSTRACT

As the density of integrated circuits continues to increase, and greater operational speeds are required, device feature sizes must be shrunk and more emphasis placed upon the interconnect structures to minimise RC delays. Copper has emerged as the most promising metal for use in advanced devices, due to its low resistivity characteristics, as well as its greater resistance to electromigration when compared to conventional Al metallisation. Damascene processing of copper has been identified as the best method for the patterning of Cu metal into interconnect structures, which also include new dielectric layers with reduced dielectric constants when compared to SiO2. The processing of copper requires the development of new processes, including new analytical techniques for the characterisation of copper surfaces and copper thin films. Electrochemical techniques have been successfully used to study oxide films and measure thicknesses of metallic coatings. This article summarises developments performed in recent years and describes applications of different electrochemical techniques for the analysis of materials used in semiconductor manufacturing.