| 摘要 |
A gate oxide layer, a polysilicon layer are patterned on a substrate. Then, a thermal oxidation is carried out to form the first silicon dioxide layer on the surface of the polysilicon layer. Then, a first silicon nitride layer is patterned on the first silicon dioxide layer, over the top of the polysilicon layer. Then, a second silicon nitride layer is formed on the first silicon dioxide layer and the first silicon nitride layer. Next, a second silicon dioxide layer is formed on the second silicon nitride layer. Then, an etching technique is used to form the side-wall spacers. The side-wall spacers composed of silicon nitride layer and silicon dioxide layer. A dielectric layer is formed on the cap layer, side-wall spacers and silicon dioxide layer. An etch with high selectivity is used to etch the dielectric layer to create a contact hole.
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