Taiwan Semiconductor Manufacturing Comp. Ltd.

Li-chun Chen

Chih-Heng Shen

Mei-Yen Li

Ding-Dar Hu

A method is disclosed for increasing the capacitance of high-density DRAM devices by microlithographic patterning. A semiconductor substrate having a MOS transistor comprising a gate and source/drain regions, and a word line and a bit line is provided. A layer of inter-poly oxide is deposited over the substrate and planarized. Contact holes are etched in the oxide layer until the substrate is exposed. A layer of photoresist is next blanket deposited over the substrate. Using microlithographic methods, the photoresist is then patterned with in-line or staggered micron size features and the underlying inter-poly oxide layer is etched using the photoresist as a mask. The resulting inter-poly oxide surface, therefore, acquires the shape of a micro-folded topography having a roughened surface area of many folds larger than the original flat surface. A first conductive layer such as polysilicon is conformally deposited over the microlithoqraphically roughened surface forming the storage electrode of the capacitor which is completed by forming a high dielectric oxide such as ONO over the first polysilicon and then depositing a second polysilicon to form the upper electrode of the capacitor.

Increasing capacitance for high density DRAM by microlithography

A method for fabricating an improved connection between active device regions in silicon, to overlying metallization levels, has been developed. A LPCVD tungsten contact plug process, which results in optimum coplanarity between the top surface of the tungsten plug and the surrounding insulator surface, has been created.

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Hsin-chu, Taiwan

Li-chun Chen