Nan Ya Technology Corporation

Hsing-Chuan Tsai

Yinan Chen

Tsu-An Lin

Tse Yao Huang

Ming-Teng Hsieh

Shih-Chi Hsu

Pei-Ying Lee

A method for fabricating a DRAM capacitor is described. First, a semiconductor substrate having a capacitor contact is provided. Next, a first polysilicon layer is formed. Then, an oxide layer and a silicon oxy-nitride layer are sequentially formed over the first polysilicon layer. Next, the silicon oxy-nitride layer, the oxide layer, and the first polysilicon layer are selectively etched to leave a rectangular stack layer. Afterwards, the oxide layer and the first polysilicon layer of the rectangular stack layer are etched from the sidewall direction to leave a double T-shaped stack layer. Then, second polysilicon layer is formed on the upper surface and the sidewall of the double T-shaped stack layer. Next, the second polysilicon layer is selectively removed. The remaining second and first polysilicon layer are used as the bottom electrode. Afterwards, a dielectric layer and an upper electrode are formed on the bottom electrode.

Method for fabricating a DRAM capacitor

A method for fabricating a cylindrical capacitor is provided. This invention uses a composite structure composed of stacked barrier/scarificing/mask layers to prevent the contact plug of the capacitor from being attacked by wet etchants. An insulating layer is formed over a substrate having a source region, a drain region, and a gate electrode. Then a barrier layer, a sacrificing layer and a mask layer are sequentially formed over the insulating layer. Next, a contact hole is formed over the source region and spacers are formed on the sidewalls of the contact hole. After a storage electrode of the capacitor is formed and exposed portions of the mask layer are removed, the sacrificing layer is isotropically etched using the spacers and the barrier layer as stopping layers. Thereafter, a capacitor dielectric layer and an opposite electrode are formed over the storage electrode thereby completing the capacitor.

Method for fabricating a cylindrical capacitor

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Taipei, Taiwan

Hsing-Chuan Tsai