TEOS Based Borophosphosilicate Glass for VLSI Devices

Borophosphosilicate (BPSG) glass is currently used as an interlevel dielectric in VLSI devices. The common deposition process uses the co-oxidation of SiH sub 4, PH sub 3 and B sub 2 H sub 6 in either the LPCVD or APCVD systems. Although, an alternate deposition process based on the pyrolitic decomposition of organic reactants has been investigated, there have been no reports of it being used in VLSI devices. We describe here the substitution of tetraethylorthosilicate (TEOS) based BPSG (acronym BPTEOS) for SIH sub 4 based BPSG glass in the fabrication of 1.25 micron technology DRAM devices (1 MBIT). BPTEOS has also been used in the fabrication of submicron CMOS ASIC devices.