Preparation method of metal nitride barrier layer

Abstract

The invention discloses a preparation method of a metal nitride barrier layer, and belongs to the technical field of semiconductor device manufacturing. The metal nitride barrier layer is prepared by adopting a physical vapor deposition method; when a metal layer is deposited, an ion source on a physical vapor deposition device generates a nitrogen ion beam, and nitrogen ion is poured into a metal layer. According to the invention, a physical vapor deposition preparation method with the assistance of plasma is adopted, the compactness of the barrier layer is improved; meanwhile the fact that the barrier layer has an amorphous structure is ensured; and amorphousness has no channel for rapid diffusion, like the crystal boundary, and is an ideal barrier layer structure.

Description

technical field [0001] The invention relates to the technical field of semiconductor device manufacturing, in particular to a method for preparing a metal nitride barrier layer. Background technique [0002] In the field of semiconductor technology, the earliest interconnection metal is Al. However, with the continuous improvement of the integration of devices, especially the development of VLSI, the feature size of devices is continuously shrinking, and the cross-sectional area and line of interconnection on the chip The pitch continues to decrease, which leads to the continuous increase of the interconnect resistance R and the parasitic capacitance C, which greatly increases the delay time constant RC of the interconnect. Since the delay time constant RC is taking an increasing proportion in the delay of the integrated circuit system, it becomes the main factor limiting the interconnection speed. [0003] In order to ensure the high speed, high integration, high stabilit...

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Problems solved by technology

[0005] 1) Cu diffuses quickly in Si and its oxides and most dielectric layers, and once Cu enters the device, it will form deep-level impurities, which have a strong trap effect on the carriers in the device, making the device performance Degradation or even failure

[0006] 2) Cu is very easy to combine with Si and SiO below 200 ℃ 2 React to form copper-silicon compound causing component failure

[0007] 3) Cu has poor adhesion to dielectric materials, resulting in insufficient mechanical strength of thin films in integrated circuits

[0008] 4) Unlike Al, Cu can form a dense oxide protective layer, so it is easy to be oxidized and corroded, thus affecting the conductive stability of metal wiring

[0011] The TaN barrier layer is usually prepared by physical vapor deposition (Physical Vapor Deposition, PVD). One problem with this method is that the film is not dense enough and there are holes, which will lead to poor barrier performance.