Method for improving thickness uniformity of deposited ozone-TEOS silicate glass layers

Abstract

The ability of the atomic force microscope (AFM) technique to detect and to characterize surface roughness of as-deposited and thermally annealed borophosphosilicate glass (BPSG) films, deposited using atmospheric and sub-atmospheric pressure TEOS-ozone based chemical vapor deposition (CVD) as well as atmospheric and low pressure silane-based CVD, have been demonstrated. The as-deposited BPSG films processed under atmospheric pressure conditions produced higher surface roughness than BPSG films deposited at a reduced pressure. Thermal treatment of BPSG glass films smoothened the film surface roughness. However, the liquid defects on the film surface were found to affect the accuracy of the roughness measurements. The AFM demonstrated to be a quick and non-destructive technique for the characterization of BPSG planarization in terms of flow angle on the step model of integrated semiconductor circuit devices. The correlation between AFM flow angle and scanning electron microscopic analysis of the same device areas showed a linear dependency for angles less than 80°.