forming materials the deposited fluorine gas enhances the filling of gaps or voids with dielectric glass compositions by etching the top of the via holes or gaps during the filling operation the present fluorine doped phosphosilicate glass compositions are stable compared to conventional phosphosilicate glass compositions which are relatively unstable and unsatisfactory for use as gap filling dielectric glass compositions application_number US 56316595 A description the novel process of the present invention is similar to conventional cvd processes and materials for depositing phosphosilicate glass films using a conventional apparatus such as illustrated by fig1 of the present drawings the novelty is imparted by the inclusion of a fluorine generating additive material which imparts fluorine gas to the plasma from which the dielectric glass film is deposited and results in the deposition of a modified psg composition namely a fluorine doped psg composition having enhanced gap fill properties and a reduced dielectric constant enhanced insulation properties the apparatus 10 of fig1 comprises a chemical vapor deposition reactor 11 having a deposition chamber 12 a perforated showerhead 13 comprising an upper electrode 14 and a lower heated susceptor electrode 15 for supporting the substrate 16 being coated such as a silicon wafer to a suitable temperature such as between 400 u00b0 and 500 u00b0 c heating of the susceptor 15 is accomplished by a bank 17 of heating lamps focused through a quartz window.