This paper presents results on rapid isothermal fusion (RIF) characteristics of phosphosilicate glass (PSG) obtained using an incoherent lamp annealer in a N2 ambient. The effects of varying the temperature (10007-1200~ the cycle duration (10-60s), and the phosphorus concentration in the glass (2.5-8.0 w/o) were investigated. The out-diffusion of phosphorus from the PSG films during RIF cycles were also studied. In conjunction with these experiments, dopant redistribution induced by typical RIF cycles in a boron-implanted silicon substrate was measured to assess the practicality of the RIF technique for VLSI applications and to identify a process window. The results for the boron profile redistribution were used as a basis of comparison between RIF and conventional furnace treatments. Although restricted to VLSI applications where a relatively high phosphorus content of approximately 8 w/o is acceptable in PSG films, it is concluded that RIF in a N~ ambient is nevertheless much more effective for the fusion of PSG films than conventional furnace processing and thus much more compatible with VLSI processing.As a part of the fabrication sequence for integrated circuits, a layer of phosphosilicate glass (PSG) is deposited to provide passivation and electrical insulation between metal interconnects and underlying structures. Before the subsequent deposition of metal takes place, it is necessary to smooth the surface topography to ensure continuity of the overlying metallization. At present, this treatment is typically a furnace glass fusion cycle at 1000~ for 30 min or more (1-5) and is the last high temperature process step in the fabrication of LSIC's. This heavy thermal load will be unacceptable for processing new generations of VLSI circuits because it will induce appreciative lateral and vertical dopant redistribution in small geometry devices.Thermal processing requirements can be eased by using different materials or ambients during the fusion cycle. Although increasing the phosphorus concentration does lead to a lower fusion temperature for PSG films, excessive concentrations eventually promote the formation of phosphoric acid in the presence of moisture (2, 4), thereby causing reliability problems due to corrosion of overlying aluminum interconnect lines. As an alternative solution, rapid isothermal fusion (RIF) has been shown in limited studies to improve PSG step coverage, while causing less junction diffusion than conventional furnace processing cycles because of its lower time-temperature product (6-9).In this work, we have studied the effect of RIF on PSG films having a practical range of phosphorus concentrations, namely, 2.5, 4.0, 6.6, and 8.0 w/o. The RIF experiments were performed in a N.2 ambient using a tungsten halogen lamp system. :~ In addition, the out-diffusion of phosphorus from the PSG films during RIF was examined.The amount of dopant diffusion induced by RIF in underlying device junction areas will largely determine its range of usefulness for VLSI applications (6-12). There-* Electrochem...