Preparation method for metal hard mask layer and copper interconnected structure

Abstract

The invention provides a preparation method for a metal hard mask layer and copper interconnected structure. The preparation method comprises the following steps: depositing a certain thickness of metal nitride on a semiconductor substrate, and conducting ultraviolet irradiation nitrogen treatment and hot reflux treatment on the metal nitride to form a metal hard mask layer. The ultraviolet irradiation nitrogen treatment and hot reflux treatment can enable the inside of the metal nitride to take sufficient nitridation and shrink, in order to generate stress tending to stretch, thereby effectively improving the flatness of the metal hard mask layer without influence to the uniformity of the specific resistance of the metal hard mask layer, and completely releasing and reducing the stress of the metal hard mask layer. Therefore, the possibility that the lower thin film of the metal hard mask layer is deformed due to the high stress of the metal hard mask layer is reduced, and the quality of the lower layer thin film of the metal hard mask layer is improved.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for preparing a metal hard mask layer and a copper interconnection structure. Background technique [0002] In 0.13μm and more advanced back-end processes, copper interconnects are widely replaced by aluminum interconnects due to lower resistivity and better anti-electromigration performance. The completion of the copper interconnection process can be achieved by using a metal hard mask layer (usually using physical vapor deposition PVD method to prepare titanium nitride TiN film). Using this process can reduce the damage caused by the low dielectric constant interlayer dielectric during the dry process, reduce the amount of photoresist, and the metal hard mask layer is a sacrificial layer, which will not be in the final product Remains, so this process is widely used in copper interconnection below 65nm. [0003] However, in the actual production process, it...

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Problems solved by technology

However, although the adjustment of the deposition parameters of the metal hard mask film reduces the stress of the film, it affects the resistivity uniformity of the film (for example, after the deposition parameters are adjusted, the resistivity uniformity of the TiN film increased from 2% to more than 8%), which will affect its subsequent etching and other processes

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