Micro/Macrocavity Method Applied to the Study of the Step Coverage Formation Mechanism of SiO2 Films by LPCVD

Abstract

The step coverage of submicron trenches by silica films formed by low‐pressure chemical vapor deposition is studied, using a novel approach called the “micro/macrocavity method” that analyzes simultaneously the growth rate profiles at millimeter and submicron scales. A mechanism is strongly indicated in which the step coverage quality is governed by the diffusion rate and sticking coefficient of only one reaction intermediate, produced from silane and oxygen in the gas phase. The step coverage is experimentally correlated with temperature, shape, and size of the trench, and is reasonably interpreted by the mechanism proposed. An approximation method for quick estimation of the step coverage is proposed.