Polishing slurry for inhibiting galvanic corrosion of copper-cobalt barrier layer and corrosive pitting of cobalt surface

Abstract

The invention belongs to the field of polishing liquid and in particular relates to polishing slurry for inhibiting galvanic corrosion of a copper-cobalt barrier layer and corrosive pitting of a cobalt surface. The polishing slurry is prepared from the following components in parts by weight: 1 to 20 parts of grinding particles, 0.001 to 5 parts of a cobalt surface protection agent, 0.001 to 5 parts of an azole compound, 0.1 to 6 parts of a complexing agent and 0.01 to 3 parts of an antioxidant; and the pH (Potential of Hydrogen) value of the polishing slurry is 7.0 to 11.0. The polishing slurry provided by the invention can be used for reducing the corrosion potential difference of cobalt and copper, and copper-cobalt galvanic corrosion density, so that the galvanic corrosion of the cobalt, which is used as an anode in a chemical and mechanical polishing process, is inhibited. Meanwhile, the corrosion potential of the copper is not obviously lower than that of the cobalt and galvaniccorrosion occurs at one side of the copper. Furthermore, the slurry also can be used for effectively inhibiting the generation and development of the corrosive pitting of the cobalt surface, and the reliability and yield of devices are improved.

Description

technical field [0001] The invention belongs to the field of polishing fluids, and in particular relates to a polishing slurry for inhibiting galvanic corrosion of a copper-cobalt barrier layer and pitting corrosion on a cobalt surface. Background technique [0002] With the development of integrated circuit technology, the integration level of devices has been continuously improved, and the feature size has been continuously reduced. At present, it has entered the ultra-deep sub-micron level, and the number of interconnection layers has reached more than ten layers. To meet the nanoscale precision required by lithography, each layer must be planarized. [0003] The chemical mechanical polishing (CMP) method is currently the most effective method to realize the global planarization of the integrated circuit surface. Specifically, the CMP process uses a polishing slurry containing abrasive particles and chemical components to planarize an integrated circuit on a polishing pa...

AI Technical Summary

Problems solved by technology

At this time, copper is easy to diffuse into the dielectric material, which affects the minority carrier lifetime of the device and the leakage current of the junction, and causes the performance of the device to be damaged or even failed.

On the other hand, the chemical composition in the polishing slurry is easy to cause corrosion to cobalt, especially pitting corrosion, resulting in more tiny point defects on the cobalt surface

Moreover, these point defects will further expand and deepen as the environmental conditions deteriorate, exacerbating the risk of device performance failure

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