Determination of Useful Life of Two-Layer Metallization Systems Via Accelerated Stressing

Accelerated testing was utilized as a means of rapidly determining the reliability, under usage conditions, of a two-level aluminum metallization -Si02 structure with level-to-level via contacts. A specially designed test vehicle containing 0.25-mil square and 0.50-mil square via contact structures was used. Electromigration was identified as the failure mechanism by SE4 analysis. Calculation of the activation energy was in agreement with an electromigration mechanism. In using the described evaluation technique, only a small quantity of units was required to arrive quickly at valid results.