Very low temperature flow planarization of psg films at below 650 deg C using a new material source, SiOP-11, Trimethylsilyl-dimethylphosphite: (CH3)3-Si-O-P-(OCH3)2

摘要

The flow properties and characteristics of PSG films containing P in the trivalent form were investigated. A new material source, SiOP-11, [Trimethylsilyl-dimethylphosphite] was used as a trivalent P source combined with HMDSO, [Hexamethyl-disiloxane] as a Si source. PSG films were deposited in the PECVD chamber using the HMDSO/SiOP-11 without using O_2. The as-deposited film containing P concentration higher than 13wtpercent showed excellent self-planarity, hygroscopic nature and instability caused by its won high P content, and execllent reflow property at below 650 deg C. It was possible to stabilize the as-deposited film by two-step annealing at 650 deg C using N_2 and O_2. Phoshorus concentration was reduced from 13wtpercent to below 5wtpercent after the first N_2 annealing. After following O_2 annealing, C content was eliminated and film was stabilized by transforming P into pentvalent form. The annealed film was close to the conventional PSG film. The results revealed that the global planarity was obtainable with HMDSO/SiOP-11 PECVD PSG film at a low temperature below 650 deg C.