| 摘要 |
A method for fabricating trench isolation structures using the reverse mask is described. The method of using a reverse mask to fabricate trench isolation structures includes providing a semiconductor substrate having a first trench and a second trench in the substrate. The first trench has a width smaller than a fixed value, while the second trench has a width larger than the fixed value, the fixed value being, for example, about 0.7 mu m. Thereafter, a conformal insulating layer is formed over the first trench and the second trench. Next, a reverse mask layer is formed over the conformal insulating layer, and then the reverse mask layer is patterned. The reverse mask layer is patterned selectively. For example, only the region directly above the second trench is covered by the reverse mask. The region directly above the first trench is exposed. Subsequently, using the patterned reverse mask layer as a mask, a portion of the conformal insulating layer is etched away forming a residual conformal insulating layer underneath the reverse mask layer. Thereafter, the reverse mask layer is removed exposing protruding insulating structures. Finally, the regions of the conformal insulating layer protruding above the semiconductor substrate are polished.
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