Abstract: A capacitor structure including a substrate, at least one first dielectric layer, at least one second dielectric layer, a capacitor, and an interconnect structure is provided. The substrate includes a capacitor region and a non-capacitor region. The first dielectric layer is located in the capacitor region and the non-capacitor region. The second dielectric layer is located in the non-capacitor region. At least a portion of the second dielectric layer is located in the first dielectric layer. A material of the second dielectric layer is different from a material of at least a portion of the first dielectric layer. A dielectric constant of the second dielectric layer is smaller than a dielectric constant of at least a portion of the first dielectric layer. The capacitor is located in the first dielectric layer in the capacitor region. The interconnect structure is located in the second dielectric layer in the non-capacitor region.

Abstract: A method of evaluating the uniformity of the thickness of the polysilicon gate layer is provided. A substrate having a dense trenches area and a sparse trenches area is provided. A plurality of first trench isolation structures are formed in the sparse trenches area of the substrate and a plurality of second trench isolation structures are simultaneously formed in the dense trenches area of the substrate. A mask layer is formed between the gaps of the first and the second trench isolation structures. A portion of the first trench isolation structures of the sparse trenches area is then removed. Then, the mask layer is removed until the surface of the substrate is exposed. A polysilicon gate layer is formed over the substrate. Finally, a planarization process is performed to remove a portion of the polysilicon gate layer.

Abstract: A method of evaluating the uniformity of the thickness of the polysilicon gate layer is provided. A substrate having a dense trenches area and a sparse trenches area is provided. A plurality of first trench isolation structures are formed in the sparse trenches area of the substrate and a plurality of second trench isolation structures are simultaneously formed in the dense trenches area of the substrate. A mask layer is formed between the gaps of the first and the second trench isolation structures. A portion of the first trench isolation structures of the sparse trenches area is then removed. Then, the mask layer is removed until the surface of the substrate is exposed. A polysilicon gate layer is formed over the substrate. Finally, a planarization process is performed to remove a portion of the polysilicon gate layer.