Semiconductor memory device and its fabricating method
DCFirst Claim
1. A semiconductor memory device comprising:
- a MOSFET including a gate electrode and source and drain regions of a second electrical conductivity type impurity material formed in a surface of a semiconductor substrate of a first electrical conductivity type material;
a bit line connected to one of the source and drain regions of said MOSFET through a bit line contact hole made in an insulating film covering the surface of said substrate on which the MOSFET is formed; and
a capacitor including a storage node electeode formed over a region where said MOSFET is formed, a capacitor insulating film and a plate electrode sequentially formed on said storage node electrode layer to be connected to another of said source and drain regions through a storage node contact hole made in said insulating film,wherein at least one of said storage node contact hole and bit line contact hole includes a first contact hole made in a first inter-layer insulating film formed over said gate electrode and a second contact hole made in a second inter-layer insulating film formed over an electrically conductive layer embedded in said first contact hole up to a level higher than the gate electrode such as to be contacted with said electrically conductive layer.
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Abstract
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.
28 Citations
9 Claims
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1. A semiconductor memory device comprising:
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a MOSFET including a gate electrode and source and drain regions of a second electrical conductivity type impurity material formed in a surface of a semiconductor substrate of a first electrical conductivity type material; a bit line connected to one of the source and drain regions of said MOSFET through a bit line contact hole made in an insulating film covering the surface of said substrate on which the MOSFET is formed; and a capacitor including a storage node electeode formed over a region where said MOSFET is formed, a capacitor insulating film and a plate electrode sequentially formed on said storage node electrode layer to be connected to another of said source and drain regions through a storage node contact hole made in said insulating film, wherein at least one of said storage node contact hole and bit line contact hole includes a first contact hole made in a first inter-layer insulating film formed over said gate electrode and a second contact hole made in a second inter-layer insulating film formed over an electrically conductive layer embedded in said first contact hole up to a level higher than the gate electrode such as to be contacted with said electrically conductive layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification