STRUCTURAL PROPERTIES OF POROUS ULTRA LOW K THIN FILMS

摘要

A new generation of porous silica thin films (Dow Corning XLK) has been developed based on hydrogen silsesquioxane (HSQ) resin treated with moist ammonia and followed by a thermal cure. The thin film properties were tailored at low dielectric constants, from 2.0 to 2.5, with excellent mechanical integrity. A number of methods have been applied to understand the structure properties of these porous low dielectric constant films. A combination of small angle neutron scattering and x-ray reflectivity was used to obtain the average pore size, porosity, and wall density information. Further, positron annihilation lifetime spectroscopy (PALS) was employed to investigate the properties of pores in the films, such as pore size and connectivity of the pores. In Addition, the pores in the films were imaged using transmission electron microscopy. The results indicate that the average dimensions of the interconnected pores in XLK films are in order of nanometers.