ELECTROMIGRATION THRESHOLD IN DAMASCENE VERSUS PLASMA-ETCHED INTERCONNECTS

Electromigration threshold has been measured for unpassivated damascen e Al(Cu) interconnects by drift experiments on Blech-type test structu res, and results are compared to equivalent plasma-etched lines. When using a damascene implementation, the critical product of current dens ity and stripe length increases significantly. As a result, the incuba tion period, needed for Cu depletion beyond a critical length, is incr eased over a wide temperature range (155-230 degrees C). This is shown to be an intrinsic effect, directly controlling the relative electrom igration performance of both metallization schemes. (C) 1998 American Institute of Physics. [S0003-6951(98)01945-7].