Metal-Insulator-Metal Capacitor

Abstract

The present invention provides a metal-insulator-metal capacitor, which comprises a semiconductor substrate; an interlayer dielectric layer disposed on the semiconductor substrate; and an insulation trench and two metal trenches all running through the interlayer dielectric layer and allowing the semiconductor substrate to be exposed; wherein the metal trenches being located on each side of the insulation trench and sharing a trench wall with the insulation trench respectively, the insulation trench being filled with insulation material as an insulation structure, the metal trenches being filled with metal material as electrodes of the capacitor.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]This application is a divisional of prior application Ser. No. 11 / 833,236, filed Aug. 3, 2007, the entire disclosure of which is hereby incorporated by reference.FIELD OF THE INVENTION[0002]The present invention relates to a semiconductor device and a fabrication method thereof, and more particularly to a metal-insulator-metal capacitor and a fabrication method thereof.DESCRIPTION OF THE RELATED ART[0003]In a very large scale integrated circuit, a capacitor is one type of commonly used passive elements. The capacitor is usually integrated into an active element such as a bipolar transistor or a Complementary Metal Oxide Semiconductor (CMOS) transistor. The current techniques for fabricating a capacitor can be classified into two groups, one employs polysilicon as electrodes and the other employs metal as electrodes. Polysilicon electrodes would bring about a problem of insufficient carriers, which leads to the capacitance changes with th...

AI Technical Summary

Benefits of technology

This approach simplifies the fabrication process, reduces costs, and avoids excessive or insufficient etching, resulting in a more reliable and cost-effective MIM capacitor with improved linearity.

Problems solved by technology

Polysilicon electrodes would bring about a problem of insufficient carriers, which leads to the capacitance changes with the surface voltage across both ends of the capacitor.

The known method for fabricating a MIM capacitor is limited by its high cost and the number of steps, since the formation of upper electrode and lower electrode should be carried out respectively and the exposure, development and etching treatment are repeated.

Moreover, due to the fact that the formation of contact holes on the upper electrode and the lower electrode is carried out simultaneously, but there is a difference in the height between the upper electrode and the lower electrode, it has the risk of an excessive etching to the contact hole connecting with the upper electrode and an insufficient etching to the contact hole connecting with the lower electrode.

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