| 摘要 |
A method for fabricating a semiconductor memory device is provided to avoid excessive loss of a storage node contact spacer by performing an over-etch process on an etch stop insulation layer while using etching equipment of a downstream type. An interlayer dielectric(32) having a storage node contact hole is formed on a semiconductor substrate(31). A storage node contact spacer(34) is formed on the sidewall of the storage node contact hole. A storage node contact plug(35) is formed in the storage node contact hole, surrounded by the storage node contact spacer. An etch stop insulation layer(36) and an insulation layer(37) for a storage node are stacked on the resultant structure. The insulation layer for the storage node and the etch stop insulation layer are sequentially etched to form a trench hole(38) that opens at least the storage node contact plug and the storage node contact spacer. An over-etch process is performed to remove the residual etch stop insulation layer wherein the storage node contact plug is more rapidly etched than the storage node contact spacer and the interlayer dielectric. A lower electrode(40) is formed in the trench hole. A dielectric layer(41) and an upper electrode(42) are sequentially formed on the lower electrode. The storage node contact plug is made of polysilicon, and the etch stop insulation layer is made of a silicon nitride layer.
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