Interface Strength Between Sub-Micron Thin Films in Opening and Sliding Delamination Modes

Delamination between thin films is classified into two types: opening mode and sliding mode. Corresponding to each mode, there is the interface strength between thin films. This paper aims to evaluate interface strength between the sub-micron thin films for opening mode and sliding mode, respectively. We already developed the evaluation method of interface fracture toughness for opening mode on the basis of fracture mechanics concept elsewhere. Moreover, the evaluation method of sliding mode is proposed and the interface strength between thin films for an advanced LSI is evaluated as the fracture toughness by using both methods. In both modes, the stress singularity appears in the vicinity of the edge of interface and governs the delamination. The criterion of crack initiation for each mode is evaluated as the interface toughness. The fracture toughness at the edge of interface in sliding mode is lower than that in opening mode.