Adhesion Degradation and Water Diffusion in Nanoporous Organosilicate Glass Thin Film Stacks

Abstract

The diffusion of water in nanoporous organosilicate glass (NPOSG) film stacks causes significant adhesion degradation of the capping layer on top of the NPOSG. We have used this adhesion degradation to estimate the diffusivity of water in a NPOSG film stack. The effective diffusivity is 1.0 × 10-9 m2/s, nearly two orders of magnitude larger than in previous generations of dense organosilicate glass film stacks. This result is consistent with the diffusion coefficient measured using secondary ion mass spectroscopy and a deuterium oxide tracer. An optical microscopy study yields similar results for the diffusion of toluene in NPOSG film stacks, but the optical technique is not suitable for measuring the diffusion coefficient of water.