Nec Corporation

Ichiroh Honma

Hirohito Watanabe

In a semiconductor device, such as a memory cell, including a capacitor, a corrugated electrode is used as a lower electrode of the capacitor and is covered with an insulation film to be opposed to an upper electrode. The corrugated electrode is specified in section by a series of folded portions which are alternately folded vertically and horizontally. Practically, the corrugated electrode is formed by a corrugated wall which surrounds a hollow space and which has a rectangular or a polygonal shape on a plane. Alternatively, the corrugated wall has an irregular surface formed by an aggregation of grains so as to effectively widen a surface of the lower electrode. Such a corrugated electrode may be manufactured by a mold which is formed by selectively etching a stack of first-kind spacer films and second-kind spacer films.

Stacked capacitor having a corrugated electrode

Used nearer to a MOS transistor (25, 29(1), 29(2)) together with another capacitor electrode (39) with a dielectric film (37) interposed for use in a DRAM, a capacitor electrode is manufactured to include a conductor pole (53) and a tray-shaped conductor layer (55) which is held by the conductor pole and to include a plate portion (57) extended perpendicular to a pole axis and having a plate periphery and a peripheral portion (59) extended parallel to the pole axis from the plate periphery towards a pole end. Preferably, the tray-shaped conductor layer is held by the pole on a plurality of levels. A planar conductor layer may additionally be held at the pole end perpendicular to the pole axis. Word (41) and bit (49) lines are embedded in an insulator layer (43, 51) for the capacitor and the transistor.

Method of manufacturing a semiconductor device wherein one of capacitor

Used nearer to a MOS transistor (25, 29(1), 29(2)) together with another capacitor electrode (39) with a dielectric film (37) interposed for use in a DRAM, a capacitor electrode comprises a conductor pole (53) and a conductor layer (55) which is held by the conductor pole and comprises a plate portion (57) extended perpendicular to a pole axis and having a plate periphery and a peripheral portion (59) extended parallel to the pole axis from the plate periphery towards a pole end. Preferably, the conductor layer is held by the pole on a plurality of levels. A planar conductor layer may additionally be held at the pole end perpendicular to the pole axis. Word (41) and bit (49) lines are embedded in an insulator layer (43, 51) for the capacitor and the transistor.

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Tokyo, Japan

Ichiroh Honma