Interconnection structure and its formation method

Abstract

An interconnection structure and its formation method are disclosed. The interconnection structure comprises a semiconductor substrate, a dielectric layer positioned on the semiconductor substrate, a first metal layer positioned on the semiconductor substrate and a second metal layer positioned, wherein the first metal layer is positioned in the dielectric layer, the upper surface of the first metal layer is lower than the upper surface of the dielectric layer, and a groove is arranged above the first metal layer. The interconnection structure also comprises a second metal layer which is positioned in the groove and is used for preventing diffusion of the first metal layer. According to the interconnection structure and its formation method, the second metal layer is deposited on the surface of the first metal layer positioned in the dielectric layer so as to prevent electromigration of atoms in the first metal layer. And then, the interconnection structure performance degradation or failure caused by electromigration of atoms in the first metal layer is avoided, and electrical properties of the formed interconnection structure are raised.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to an interconnection structure and a forming method thereof. Background technique [0002] In the existing semiconductor process, aluminum is usually used as the material of the interconnection structure; however, because copper has higher electrical conductivity and better anti-electromigration characteristics, copper gradually replaces aluminum and is widely used in VLSI in the interconnection line. However, in the process of using copper as an interconnection line, it is found that copper is easy to diffuse rapidly in the dielectric layer, which may cause high leakage current and breakdown of the dielectric layer. Provides a barrier layer that prevents copper diffusion. [0003] With the development of VLSI, especially the continuous reduction in the size of high-performance logic devices, the barrier layer cannot completely prevent copper from diffusing fr...

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Problems solved by technology

However, using N 2 or H 2 The principle of plasma reduction is based on the fact that the plasma is ionized under high pressure into ion atoms, etc., and the reduction reaction occurs with the surface of the copper interconnection line, and CuO is reduced to Cu, but the metal atoms are still in an unstable state, which is very important for suppressing the loss of copper ions, And the effect of improving time-related dielectric breakdown is not obvious

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