Improvement in the electromigration lifetime using hyper-textured aluminum formed on amorphous tantalum-aluminum underlayer

A new fabrication technique for hyper-textured aluminum (Al) films has been developed by using an amorphous tantalum-aluminum (Ta-Al) underlayer. The full width at half maximum (FWHM) value of the (111) rocking curve for Al film has been attained to be less than 1 degree. It has been clarified that the empirical relation between the electromigration (EM) lifetime of an Al interconnection /spl tau/ and the FWHM value /spl omega/ is described as /spl tausup /spl prop/spl omegasup -2/. This result has confirmed that a hyper-texture is a promising approach to withstand higher current densities required in future ULSIs.<
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