AVS 58th Annual International Symposium and Exhibition
    Electronic Materials and Processing Division Wednesday Sessions
       Session EM-WeM

Invited Paper EM-WeM11
Molecular Strengthening Mechanisms for Low-k Dielectrics

Wednesday, November 2, 2011, 11:20 am, Room 210

Session: Low-k Materials and Devices
Presenter: Reinhold Dauskardt, Stanford University
Correspondent: Click to Email
Hybrid organic-inorganic glass films processed from small organosilane precursors exhibit unique electro-optical properties while maintaining excellent thermal stability. Processed using either sol-gel or plasma-enhanced chemical vapor deposition they have application in emerging CMOS, nanoscience and energy technologies. A fundamental challenge for their integration, however, remains their inherently mechanically fragile nature that derives from the oxide component of the hybrid network and the presence of terminal hydroxyl and organic groups that reduce network connectivity. Also, to achieve ultra-low dielectric properties (i.e k < 2.4) nanoporous forms of the hybrid films are required which further reduce mechanical properties. We describe the development of computational methods to address the fundamental relationship between molecular structure and resulting mechanical and fracture properties of organosilicate glasses. Using molecular dynamics and a simulated annealing approach, large distortion-free hybrid glass networks with well-controlled network connectivity can be generated. With this capability along with a novel fracture model and molecular dynamics simulations of elastic deformation, we elucidate the critical effect of network connectivity and nanoporosity on mechanical properties. The accuracy of our computational tools is confirmed through comparison to synthesized hybrid films where the molecular structure, connectivity and nanoporosity is carefully controlled. Having predictive models for how molecular structure affects mechanical properties offers the opportunity for computational design of new glasses and provides a quantitatively accurate rationale for guiding precursor selection. Thus in addition to the fundamental insights gained regarding structure-mechanical property relationships, we will present our efforts to apply these tools to design new neat and nanoporous glasses with exceptional mechanical properties and low density.