Copper interconnection structure and forming method thereof

Abstract

The invention provides a copper interconnection structure and a forming method thereof. The forming method of the copper interconnection structure comprises the following steps of: providing a semiconductor substrate, wherein the semiconductor substrate is covered with a first dielectric layer and a first opening is formed on the first dielectric layer; filling metal copper in the first opening to form a copper plug, wherein the surface of the copper plug is flush with the surface of the first dielectric layer; etching the first dielectric layer and removing a part of the first dielectric layer, which is connected with the side wall of the copper plug, so as to form a gap between the copper plug and the first dielectric layer; forming a second dielectric layer which covers the surfaces of the first dielectric layer and the copper plug and seals the gap; forming a second opening on the second dielectric layer above the copper plug, wherein the width of the second opening is less than the width of the copper plug and the copper plug is exposed out of the bottom of the second opening; and filling cobalt tungsten phosphorus in the second opening. Through adoption of the forming method of the copper interconnection structure, metal ions can be prevented from diffusing into the dielectric layers, thereby improving reliability.

Description

technical field [0001] The invention relates to semiconductor manufacturing technology, in particular to a copper interconnection structure and a forming method thereof. Background technique [0002] With the development of semiconductor technology, the integration level of VLSI chips has reached hundreds of millions or even billions of devices, and multi-layer metal interconnection technology with more than two layers is widely used. Traditional metal interconnects are made of aluminum metal, but with the continuous reduction of device feature size in integrated circuit chips, the current density in metal interconnect lines continues to increase, and the required response time continues to decrease. Traditional aluminum The interconnection line can no longer meet the requirements. After the process size is smaller than 130nm, the copper interconnection line technology has replaced the aluminum interconnection line technology. Compared with aluminum, metallic copper has a l...

AI Technical Summary

Problems solved by technology

Because low-k materials and ultra-low-k materials are relatively loose and have a large number of voids, it is easier to cause the diffusion of metal ions14, causing TDDB problems and affecting the reliability of copper interconnection structures

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