Evaluation of Narrow Gap Filling Ability in Shallow Trench Isolation by Organosiloxane Sol-Gel Precursor

Abstract

High quality SiO2 film formation in the narrow trench pattern is important for many applications such as large scale integration (LSI) circuit and micro electro mechanical system (MEMS) industry. We have evaluated the process conditions, electrical properties, structural characteristics, and gap filling abilities of SiO2 film using organosiloxane-based silica sol-gel precursor derived from the mixture of tetraethoxysilane (TEOS) and methyltrimethoxysilane (MTMS) by changing the molar ratio of TEOS/MTMS. This sol-gel precursor was converted to high quality SiO2 film by optimizing baking conditions. The SiO2 film from this sol-gel precursor has excellent dielectric characteristics of low leakage current density and high breakdown voltage whose values are comparable to those of thermal oxide SiO2 film. In addition, the breakdown field intensity of these films was improved by adding a small amount of metal oxide such as TiO2, HfO2, and ZrO2. Furthermore, by introducing the optimum pressure (<26666 Pa) in the oxidation baking process, the film has excellent surface planarization and uniformly gap filling abilities of narrow trench pattern without void formation