High Temperature Subatmospheric Chemical Vapor Deposited Undoped Silicate Glass: A Solution for Next Generation Shallow Trench Isolation

Undoped silicate glass deposited using the tetraethylorthosilicate (TEOS) and ozone thermal reaction has been selected as one of the candidates for shallow trench isolation applications. As a replacement for existing low pressure or atmospheric pressure chemical vapor deposition processes for device dimensions below 0.25 μm, TEOS/ozone films deposited at high temperature (>550°C) exhibit the superior qualities in terms of void-free trench fill. In this paper, we present some characterization of the silicon oxide film deposited in the subatmospheric pressure regime using TEOS/ozone chemistry, aimed at developing a high-quality dielectric film to meet shallow trench isolation gap-fill requirements. It is also identified that low ozone/TEOS ratio reduces surface and pattern sensitivity. Therefore, no additional treatment or predeposition is necessary. Moreover, to enhance the etch resistance of the silicon oxide, the as-deposited film is annealed at high temperature for densification and bond reconstruction.