Merchant & Gould P.C.
Method to reduce aspect ratio of DRAM peripheral contact
 The present invention provides a method for reducing aspect ratio of DRAM peripheral contact so as to achieving a good contact etching and metal deposition by utilizing conventional equipment. Besides, the present invention provides a stop layer formed by a nitride layer to reduce the volcano effect resulted from the misalignment between stacked contacts. Furthermore, the present invention is capable of etching poly layer and oxide layer in a single step, whereby the height of the peripheral contact is substantially the same as, or lower than, the contact of the storage node of a capacitor. Therefore, the aspect ratio of DRAM peripheral contact can be reduced. 
Taiwan Semiconductor Manufacturing Co., Ltd.
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inventional inventional inventional
Cheng-Yuan Cheng-Yuan Yeur-Luen
Chang Hsu Tu