METHOD FOR MANUFACTURING LOW-STRESS SILICON NITRIDE MEMBRANE

摘要

PURPOSE: A method for manufacturing a low-stress silicon nitride membrane is provided to improve uniformity of thickness and composition of the low-stress silicon nitride membrane having a silicon-rich composition, thereby improving reproducibility and quality of microstructures by increasing diffusion coefficient of a raw gas. CONSTITUTION: The method for manufacturing a low-stress silicon nitride membrane by a low pressure chemical vapor deposition is characterized in that a diffusion coefficient is increased as properly controlling a composition ratio of the raw gases by using SiH2Cl2 and NH3 as raw gases and using a diluting gas for increasing the diffusion coefficient of the raw gases, wherein the diluting gas includes nitrogen gas or an inert gas such as helium and argon. The chemical reaction by-products according to the low pressure chemical vapor deposition are smoothly exhausted using an exhausting line having a high conductance and a vacuum pump having a high displacement capacity so as to increase uniformity of composition and thickness of the low-stress silicon nitride membrane, and the density of a composition of raw gases is relatively uniformly maintained by properly controlling the relative amount of raw gases diluting gases, thereby improving uniformity of composition and thickness of the low-stress silicon nitride membrane that can be applied to the fields of semiconductors and MEMS (MicroElectro Mechanical system).