Polishing solution based on polishing process of metal Co and application thereof

Abstract

The invention discloses a polishing solution based on a polishing process of metal Co and application thereof. The polishing solution comprises the following raw material components in percentage by weight: 0.01-2% of inhibitor, 0-5% of oxidant, 0.1-10% of grinding granules, 0.001-10% of chelating agent and the balance of water, wherein the pH value of the polishing solution is adjusted to 3-5 by a pH value adjusting agent; the inhibitor is selected one or more of five-membered heterocyclic ring derivatives containing S and / or N; the oxidant is selected from one or more of hydrogen peroxide, ammonium persulfate, potassium periodate and potassium perchlorate; the grinding granules are selected from one or more of silicon dioxide, cerium dioxide and alumina; and the chelating agent is selected from amino acid or citric acid or a mixture thereof. The polishing solution disclosed by the invention can effectively inhibit the static corrosion of cobalt, reduce the polishing rate of cobalt and prevent the over-corrosion of cobalt in the polishing process.

Description

technical field [0001] The invention relates to the technical field of microelectronic technology, in particular to a polishing liquid for microelectronic polishing technology and its application. Background technique [0002] As ultra-large-scale integration (ULSI) technology has evolved to smaller device sizes, the size of the back-end copper interconnects has also shrunk. In order to reduce the interconnection delay, the barrier layer and adhesion layer in the copper interconnection structure are getting thinner and thinner. The traditional copper adhesion layer / barrier layer-Ta / TaN can no longer meet the requirements because of the relatively high resistivity of Ta , and Ta cannot be used as a seed layer for direct copper plating. Metal cobalt (Co) is relatively cheap and has good adhesion to copper. Cu is easy to nucleate on Co, and Co has low resistivity. It can also be used as a direct electroplating seed layer for copper. Cobalt or cobalt alloys have been experimen...

AI Technical Summary

Problems solved by technology

However, experiments have found that in the presence of oxidants (H 2 o 2 ) in the acidic solution, both copper and cobalt are very soluble, which makes the polishing rate of copper and cobalt too fast during the polishing process, which easily leads to the appearance of dishing of copper

The dissolution of cobalt can easily lead to the dissolution of cobalt in the trench and lead to the desorption of copper.

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