Fracture Property Improvements of a Nanoporous Thin Film Via Post Deposition Bond Modifications

For 90 nm node devices, the group of materials known as organosilicate glass (OSG) has emerged as the predominant choice for intermetal dielectrics. A potential failure mechanism for this class of low-k dielectric films during the manufacturing process is catastrophic fracture due to channel cracking. The use of an electron beam curing process is being investigated for improvement in the mechanical strength of these silicon-based materials. Within this work, the effects of curing dose (micro-C/cm2) upon the mechanical properties of OSG thin films were characterized. For a set process voltage and current, linear relationships exist between the dose and several mechanical film properties. Channel crack growth velocities were also measured for these cured materials. As the cure dose is increased, the crack growth rate decreases according to a power law relationship. The structural film changes induced by the electron beam cure process are addressed, focusing on their impact upon the mechanical strength of OSG thin films.