Kabushiki Kaisha Toshiba

Naoko Okabe

Takashi Yamada

Akihiro Nitayama

Kazumasa Sunouchi

Hiroshi Takato

Satoshi Inoue

Katsuhiko Hieda

Tohru Ozaki

Fumio Horiguchi

Satosi Inoue

Kouji Hasimoto

In a DRAM having a structure in which a storage node electrode is formed via an insulator film in a trench formed in a memory cell region to thereby form a capacitor, and in which the storage node electrode is connected in the source/drain regions of a MOSFET through a storage node contact formed in a part of the insulator film, the trench is disposed so as to deviate widthwise in a channel region of the MOSFET, so that the distance between adjacent element regions is reduced without causing misalignment of masks used in the formation of the storage node contact, thereby to provide a miniaturized high-reliability DRAM. In addition, the storage node contact and the trench can be formed in large size.

Semiconductor memory device

A semiconductor memory device wherein at least one of a storage node contact hole and a bit line contact hole includes a first contact hole made in a first inter-layer insulating film formed over a gate electrode and a second contact hole made in a second inter-layer insulating film formed over an electrically conductive material embedded up to a level higher than the gate electrode in the first contact hole which is contacted with the electrically conductive material, the conductive material being exposed by etching a part of the second inter-layer insulating film, whereby the size of the memory device can be made small and the reliability can be improved. Further, a capacitor is formed in a layer higher than a bit line thereby to facilitate the processing of a storage node electrode to increase the capacitor area and to improve the reliability since it is unnecessary to carry out patterning a plate electrode within a cell array. With the above construction, a short-circuiting between the embedded layers is removed and a good quality of the second inter-layer insulating film is formed.

Method of fabricating a semiconductor memory device

Semiconductor memory device and its fabricating method

Growing community of inventors

Yokohama, Japan

Naoko Okabe