With IC technology nodes >20 nm, chemical mechanical polishing (CMP) of Co-based Cu interconnection has changed to one-step polishing, which requires a rapid removal rate (RR) of Cu while controlling the height differences of Cu surface. Co as the barrier material also requires a lower RR to ensure a high Cu/Co RR selection ratio. Choosing the appropriate inhibitor in the slurry is extremely important. TTA was thoroughly examined in this study for its ability to prevent corrosion on Cu film. The results showed that TTA can effectively inhibit the removal of Cu under both dynamic and static conditions, which was confirmed by scanning electron microscopy and atomic force microscopy. TTA's corrosion inhibition mechanism was further revealed by electrochemical, quantum chemical calculation, UV-Visible, and X-ray photoelectron spectroscopy tests. It was found that TTA can inhibit corrosion of Cu by physical and chemical adsorption on the Cu surface. At the same time, it was also found TTA can inhibit corrosion of Co by forming Co-TTA and promoting the conversion of Co(OH)2 to Co3O4, and a Cu/Co removal rate selection ratio of 104 was obtained, which provides a suitable corrosion inhibitor for the polishing of Co-based Cu interconnection CMP and has broad application prospects.
With integrated circuit (IC) technology nodes below 20 nm, the chemical mechanical polishing (CMP) of cobalt (Co)-based copper (Cu) interconnection has been gradually changed to one-step polishing, which requires rapid removal rate (RR) of Cu while controlling the height differences of concave and convex areas on the Cu surface, and finally achieving global planarization. Co as the barrier material is also required a lower RR to ensure a high Cu/Co removal rate selection ratio. Therefore, choosing the appropriate inhibitor in the slurry is extremely important. The corrosion inhibitor 5-methyl-benzotriazole (TTA) was thoroughly examined in this study for its ability to prevent corrosion on Cu film as well as its mode of action. The experimental results showed that TTA can effectively inhibit the removal of Cu under both dynamic and static conditions, which was also confirmed by scanning electron microscopy (SEM) and atomic force microscopy (AFM) tests. The corrosion inhibition effect and mechanism of TTA was further revealed by open circuit potential (OCP), polarization curve, adsorption isotherm, quantum chemical calculation, UV-Visible and X-ray photoelectron spectroscopy (XPS) tests. It was found that TTA can inhibit the corrosion of Cu by physical and chemical adsorption on the Cu surface, which is conductive to obtain excellent planarization properties. At the same time, it was also found TTA can also inhibit the corrosion of Co by forming Co-TTA and promoting the conversion of Co(OH)2 to Co3O4, and a Cu/Co removal rate selection ratio of 104 was obtained, which provides a suitable corrosion inhibitor for the polishing of Co-based Cu interconnection CMP and has a broad application prospect.
To protect the copper (Cu) surfaces from corrosion during chemical mechanical polishing (CMP), selecting appropriate inhibitors are critical. Benzo and its derivatives are potential superior inhibitors due to their diverse heteroatoms and environmentally friendliness. In this study, benzothiazole (ABT), 2-benzothiazolamine (2-ABT) and 2-aminobenzimidazole (2-ABI) were used as inhibitors to investigate the effect of molecular structure on the inhibition performance through experimental and theoretical calculation. With the addition of inhibitors, the removal rates were all inhibited effectively and the inhibition efficiency was in the following order: 2-ABI > 2-ABT > ABT. Electrochemical experiments and surface morphology tests demonstrated that the inhibitors could prevent corrosion by forming dense passivation film on Cu surfaces with a high inhibition efficiency of 88%, 94 %, and 95%, and improve the surface quality after CMP. Calculation results revealed that the introduction of amino groups (–NH2) and nitrogen(N) atom into five-membered ring enhanced the inhibition effect due to the larger adsorption energy, stronger ability to contribute electrons and denser passivation film which consistent with the experiment. Such study confirms the benzimidazole derivatives are potentially inhibitor for Cu film CMP and provides a new reference to design and select novel inhibitors.
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