Metal layer-insulator layer-metal layer capacitor and manufacturing method thereof

Abstract

The invention provides a metal layer-insulating layer-metal layer capacitor and belongs to the field of in-chip capacitors of integrated circuits. The metal layer-insulating layer-metal layer capacitor comprises a first metal layer; a non-capacitor region and a capacitor region are defined on the first metal layer; a plurality of cofferdam side walls which are located in the capacitor region are arranged on the surface of the first metal layer; the cofferdam side wall includes a first dielectric layer located at the bottom and a first barrier layer located on the first dielectric layer; grooves are correspondingly formed in the cofferdam side walls; a capacitor lower pole plate, a capacitor dielectric layer and a capacitor upper pole plate are sequentially arranged at the surfaces of the cofferdam side walls and the grooves; a conducting plug layer is arranged on the capacitor upper pole plate; and a second metal layer is arranged on the conducting plug layer. According to the MIM (metal layer-insulating layer-metal layer) capacitor of the invention, a stereoscopic structure is adopted, and therefore, effective electrode areas corresponding to the capacitor upper pole plate and the capacitor lower pole plate are increased, and capacitance density can be increased, and thus, a larger capacitance value can be obtained based on a limited chip area, and requirements of large-capacitance integrated circuits such as an LCD driving circuit and an RFCMOS circuit can be satisfied. The metal layer-insulating layer-metal layer capacitor can be used as in-chip capacitors of integrated circuits.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to a metal layer-insulation layer-metal layer capacitor and a manufacturing method thereof. Background technique [0002] The application of capacitors is always a lever in integrated circuit design. Designers hope to use capacitors with as large a capacitance as possible, but large capacitances often lead to increased chip area and increased manufacturing costs. How to increase the capacitance value per unit chip area (that is, capacitance density) has always been a challenge in the field of integrated circuits. [0003] Existing capacitors can be roughly divided into front-end capacitors and back-end capacitors, front-end capacitors such as MOS capacitors, PN junction capacitors, back-end capacitors such as MIM (metal layer-insulation layer-metal layer) capacitors, MOM (metal layer- oxide layer - metal layer) capacitor. Among them, MIM capacitors can provide better frequency a...

AI Technical Summary

Problems solved by technology

For MIM capacitors with a planar structure, the capacitance density can reach up to 4 - 6 fF / μm 2 , but in practical applications, it is still far from meeting the needs of large-capacitance integrated circuits such as LCD drive circuits and RFCMOS circuits.

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