Phosphorous doped SOG as a pre-metal-dielectric for sub-50 nm technology nodes

The goal of this work is to find a substitute for chemically-vapour-deposited (CVD) Borophosphosilicate glass (BPSG), which is currently used as a pre-metal dielectric (PMD) for sub 50 nm. Two spin-on candidates are considered, out of which one contains four weight percent (wt.%) of phosphor. First, their material properties are discussed and then their integration challenges are presented. Particularly, issues like thermal budget, direct CMP capability and compatibility to wet-cleans are explored. Then the suitable candidate is tested electrically.