Double-nested copper interconnection structure and fabrication method thereof

Abstract

The invention provides a double-nested copper interconnection structure and a fabrication method thereof. In the double-nested copper interconnection structure, the metal diffusion barrier layer on the surface of a metal connection line is surrounded by a nitrogen-doped layer, or the metal diffusion barrier layer of the partial surface of the metal connection line and a conductive plug that located in an interlayer dielectric layer is surrounded by a nitrogen-doped layer. The nitrogen-doped layer is obtained through nitrogen or ammonia gas plasma treatment. The nitrogen-doped layer can be used to improve the adhesive power between the interlayer dielectric layer and metal, and the mechanical strength between the nitrogen-doped layer and a second cap layer is higher, so that the adhesive power between copper and the second cap layer can be further improved, the electromigration resistance of devices can be improved, and the nitrogen-doped layer can also be used to further prevent copper from being diffused into the interlayer dielectric on the basis of the metal diffusion barrier layer to prevent the short-circuit phenomenon from occurring on the devices.

Description

technical field [0001] The invention belongs to the field of semiconductor manufacturing, and relates to an interconnection structure and a manufacturing method thereof, in particular to a double-nested copper interconnection structure and a manufacturing method thereof. Background technique [0002] With the rapid development of integrated circuit CMOS technology in accordance with Moore's Law, interconnection delay gradually replaces device delay as a key factor affecting chip performance. The parasitic capacitance and interconnection resistance between the interconnections cause the transmission delay of the signal. Since copper has low resistivity, excellent anti-electromigration characteristics and high reliability, it can reduce the interconnection resistance of the metal, thereby reducing the overall interconnection delay effect, and has now changed from conventional aluminum interconnection to low Resistor copper interconnects. At the same time, reducing the capaci...

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Problems solved by technology

[0006] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a dual-nested copper interconnection structure and a manufacturing method thereof, which are used to solve the problems caused by the poor adhesion between the metal and the medium in the prior art. The phenomenon of open circuit or high contact resistance, and the problem that the diffusion barrier layer is too thin makes copper easy to diffuse into the medium and cause short circuit of the device

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