Abstract: A method of fabricating a shallow trench isolation (STI) structure. A substrate is provided and then a pad oxide layer, a mask layer and a first trench are sequentially formed on the substrate. An insulation layer is formed inside the first trench and over the substrate. The insulation layer has a second trench in a location above the first trench. Thereafter, a conformal cap layer is formed over the insulation layer. The cap layer has a third trench in a location above the second trench. A reverse mask is formed over the cap layer covering the third trench. The cap layer and the insulation layer outside the reverse mask are removed to expose the upper surface of the mask layer. The reverse mask is removed and then the residual insulation layer outside the remaining cap layer and the trench are moved to expose the upper surface of the mask layer. Finally, the mask layer and the pad oxide layer are removed.

Abstract: A method of fabricating a shallow trench isolation (STI) structure. A substrate is provided and then a pad oxide layer, a mask layer and a first trench are sequentially formed on the substrate. An insulation layer is formed inside the first trench and over the substrate. The insulation layer has a second trench in a location above the first trench. Thereafter, a conformal cap layer is formed over the insulation layer. The cap layer has a third trench in a location above the second trench. A reverse mask is formed over the cap layer covering the third trench. The cap layer and the insulation layer outside the reverse mask are removed to expose the upper surface of the mask layer. The reverse mask is removed and then the residual insulation layer outside the remaining cap layer and the trench are moved to expose the upper surface of the mask layer. Finally, the mask layer and the pad oxide layer are removed.