A novel test structure to study intrinsic reliability of barrier/low-k

Abstract

A novel test structure to study intrinsic reliability of barrier/low-k is proposed. The structure is based on a planar capacitor design where low-k film is deposited after the patterning of the capacitor, followed by metallization and Cu CMP. This so called low-k planar capacitor structure provides several unique capabilities to study various aspects of barrier/low-k TDDB compared with the conventional damascene structures. Two of the unique capabilities are presented in this paper. First, TDDB from a damage-free low-k material has been measured for the first time using the low-k planar capacitor structure. Second, the test structure is sensitive enough to quantify the impact of selected process conditions, such as barrier re-sputter and plasma treatments, on TDDB.