Abstract: A method of forming a metal-insulator-metal capacitor. A substrate is provided and then a first dielectric layer is formed over the substrate. The first dielectric layer is patterned to form a first opening for forming a desired lower electrode and a second opening for forming a desired conductive line. A first metallic layer conformal to the exposed surface of the first opening and completely filling the second opening is formed. A conformal capacitor dielectric layer is formed over the first metallic layer and then a second dielectric layer is formed over the capacitor dielectric layer. The second dielectric layer is patterned to form a third opening above the first opening and a fourth opening above the second opening. The third opening exposes a portion of the capacitor dielectric layer and the fourth opening exposes a portion of the first metallic layer. Finally, a second metallic layer that completely fills the third opening and the fourth opening is formed.

Abstract: An optical method for measuring a trench depth, applicable to a substrate having a trench therein, wherein the substrate has a first surface, and the trench has a bottom surface to serve as a second surface as well as a depth. The method involves measuring a total reflectance from the substrate using different wavelengths, wherein the total reflectance is determined by a first actual reflectance from the first surface, a second actual reflectance from the second surface, and a scattering factor. The second actual reflectance is then determined from the measurement of the first actual reflectance from the first surface and the calculation result of the scattering factor. Since a trench depth is determined from the second actual reflectance, the trench depth is calculated after acquiring the second actual reflectance.

Abstract: A method for making a multi-layer polysilicon plug forms a plurality of undoped polysilicon thin layers alternating with a plurality of doped polysilicon thin layers on a substrate having a concavity until the polysilicon layers fill the concavity. Thus, a multi-layer polysilicon layer is formed. The multi-layer polysilicon layer is patterned and etched to form a multi-layer polysilicon plug in the concavity.