Enhancement of moisture resistance of spin-on low- k HSQ films by hot wire generated atomic hydrogen treatment

Abstract

Spin on hydrogen silsesquioxane (HSQ) is a material with low dielectric constant ( k) and shows potential as intermetal dielectric (IMD) layers for future VLSI circuits. One major challenge in the integration of these films is the moisture uptake with time, which degrades the electrical performance and hence limits their application. In the present work, we show (under accelerated conditions) that the as deposited films absorb moisture significantly which is reflected in the related signatures in the infrared (IR) spectroscopic data. Subsequently there is an increase in the leakage current with a concurrent decrease in the electrical breakdown field. Upon treatment with atomic hydrogen generated by a hot filament ( T F = 1900 °C), drastic reduction in the moisture absorption is observed. Also there is almost a 2 orders of magnitude reduction in the leakage current and no indication of any electrical breakdown within the range of applied field.