ELECTROMIGRATION IN TWO-LEVEL Cu INTERCONNECTIONS WITH A LOW DIELECTRIC CONSTANT INTER-LEVEL INSULATOR

摘要

The electromigration lifetime in a two-level Cu dual damascene interconnect with a low dielectric constant inter-level dielectric has been measured. Two distinguishable groups of failure times were observed. The shorter lifetime group was found to have void growth in the M2 line/via vicinity and the void size was consistent with the value predicted by Cu drift velocity. The long lifetime group was due to Cu diffusing through the diffusion barrier layer present between the levels. The failure mechanism in the long lifetime group was similar to the result obtained when testing a single stripe with two large reservoirs.