Method of fabricating self-align contact window with silicon nitride side wall

摘要

The process of the present invention has numerous advantages over the prior art. The silicon nitride side-wall spacers permit a small contact hole thus miniaturizing the cell beyond lithographic limits. The side-wall spacers composed of silicon nitride and silicon dioxide avoid to expose the polysilicon when the contact window is formed by etching step. Moreover, the highly selective etching process improve the accuracy of the contact window.