| 摘要 |
A substrate including a memory cell region and a peripheral circuit region is provided. A first dielectric layer, a first conductive layer and a mask layer are formed on the substrate. Isolation structures are formed, and the isolation structures in the memory cell region are denser than that in the peripheral circuit region. A protective layer is formed on the substrate in the second region. The mask layer in the first region is removed. A second conductive layer is formed on the substrate, wherein the protective layer has an etching selectivity the same to that of the second conductive layer. Portion of the second conductive layer and the protective layer are removed by using the isolation structures as stop layer. Portion of the isolation structures and the mask layer in the peripheral circuit region are removed. A second dielectric layer and a third conductive layer are formed on the substrate.
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