Process Characterization of PSG and BPSG Plasma Deposition

A concern in the fabrication of nigh density integrated cir-cuitry is the topography of interlayer dielectric steps over which metal conductor lines will pass. These steps, occurring as a result of underlying topography or via etching, should be gradually ta-pered to ensure continuity in subsequently deposited metal inter-connect lines. Tapered steps can be achieved by reflow of phos-phosilicate (PSG) or borophosphosilicate glass (BPSG) interlayer dielectric at device-compatible temperatures. PSG and BPSG dep-osition has been demonstrated using atmospheric-CVD(1), low-pressure-CVD(2), and recently, using plasma enhanced CVD in tube-type systems (3-5). In this communication, wereport on process characterization of plasma-enhanced d position of PSG and BPSG. A parailel-plate cold wail plasma deposition system was used. Descriptio