Application of borophosphosilicate glass (BPSG) in microelectronic processing

Abstract

In semiconductor industry borophosphosilicate glass (BPSG) films formed by chemical vapor deposition (CVD) are widely utilized as dielectric layers between conductor lines. This glass has to provide void-free fill of 0.2-0.5 pm wide spaces between conducting lines with aspect ratios up to 4: 1. Therefore good glass reflow properties, which are a function of boron and phosphorus dopant concentration and of deposition and anneal temperature, are required. Dopant concentrations need to be low enough to avoid undesired surface crystallization phenomena and to provide a stable surface. Anneal temperatures have to be low to fulfill the thermal budget criteria of advanced silicon devices.