Thin Solid Films, Vol.352, No.1-2, 77-84, 1999
Investigation of borophosphosilicate glass roughness and planarization with the atomic force microscope technique
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 row 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 degrees.
Keywords:atomic force microscopy (AFM);chemical vapor deposition (CVD);silicon oxide;surface defects