Mechanical properties, adhesion and fracture toughness of low-k dielectric thin films for microelectronic applications

Due to the radical compromise in thermal and/or mechanical properties that the migration from silicon dioxide to novel low-k dielectric films necessarily incurs, the IC industry is motivated to better understand the failure modes of low-k dielectric films. These failure modes include thermal instability, poor mechanical strength, and chemicalmechanical polishing (CMP) failure due to low cohesive and adhesive fracture toughness. By developing a methodology to predict failure modes, we are able to screen multiple candidate low-K materials. The following study is a discussion of some of the experimental approaches that Motorola has taken to understand and mitigate some of these failure mechanisms.