Micro villus patterning (MVP) technology for 256 Mb DRAM stack cell

Conference Paper · July 1992
DOI: 10.1109/VLSIT.1992.200619 · Source: IEEE Xplore
Conference: VLSI Technology, 1992. Digest of Technical Papers. 1992 Symposium on


    Micro villus patterning (MVP) technology which delivers the
    maximized cell capacitance is discussed. The key feature of the MVP
    technology is the formation of a hemispherical grain (HSG) archipelago
    and its transference to the underlayered oxide. The HSG archipelago
    pattern is produced on the oxide layer, and, by using that pattern as an
    etch mask, the oxide archipelago pattern is again transferred to the
    storage poly for the formation of villus bars by anisotropic dry etch.
    After the etching process, the oxide etch mask pattern is stripped away
    by using oxide wet etchant, so that additional Fin undercut structure is
    achieved underneath the main body. The main body of the storage
    electrode can be formed by single deposition and etch process, so that
    the storage electrode structure is strong enough to maintain its
    physical stability in spite of the complication of its shape. A 256-Mb
    DRAM-cell size of 0.6~0.8 μm<sup>2</sup> having more than 30 fF of
    cell capacitance with a stack structure, has been realized