The flow characteristics of borophosphosilicate (TEOS based) glass

The authors examine the role of boron and phosphorus concentrations in the flow characteristics of borophosphosilicate (TEOS based) glass. The glass was deposited using TEOS (tetraethylorthosilicate), phosphine and TMB (trimethylborate), as precursors. Previous studies on the flow characteristics have relied on scanning electron microscopy (SEM) work to study the flow. In this work, however, the authors present a quantitative study of flow as measured using electrical flow testers which measured the metal resistance ratios over topography to those over flat for polysilicon spacings from 0.4 μ to 4.0 μ. They have studied the effect of boron and phosphorus concentrations in the regime of 3.5%-4.4% as measured using FTIR. It is found that the boron concentration is more dominant in determining the flow characteristics than the phosphorus concentrations. Further, it has also been found that the duration of the flow especially at the lower concentrations of boron (<4.0%) is important in determining the glass flow. SEM work is also presented in this study to augment the electrical data