Thermally and Chemically Robust, Non-Reflowable Low-k Spin-on Glass (k = 2.4) for Gap-Filling Technology in Sub-50-nm Memory Devices

A novel non-reflowable low-k spin-on glass (NR-SOG, k = 2.4) has been developed for the gap-filling technology in sub-50-nm memory devices. The new SOG has planarizing and gap-filling capabilities as high as conventional reflowable SOGs have, while it has thermal stability up to 800degC and chemical stabilities against HF and amine. A damage-less via-formation process for integrating NR-SOG into interconnects, where an amine-based solution is used for photoresist removal, was also developed. The fabricated fine-pitch interconnects with minimum spacing of 50 nm showed sufficiently low line-to-line capacitance and high TDDB reliability