Synergetic Effect of 5-Methyl-1H-Benzotriazole and Sodium Dodecyl Benzene Sulfonate on CMP Performance of Ruthenium Barrier Layer in KIO₄-Based Slurry

Abstract

The chemical mechanical polishing (CMP) of ruthenium barrier layer of copper interconnection for 14 nm and below technology node has been connected with more challenges, among which the corrosion of copper and ruthenium and the selectivity of removal rate between ruthenium and copper has attracted more attention. This paper mainly focus on the influence of 5-methyl-1H-benzotriazole(MBTA) and sodium dodecyl benzene sulfonate (SDBS) on the polishing properties of copper and ruthenium during ruthenium barrier CMP in the KIO4-based solutions. The results show that the removal rate and corrosion current density of ruthenium decrease with the increase of MBTA concentration. Subsequently, it is demonstrated that the formation of passivating film on ruthenium surface is due to the physisorption of MBTA, which occupies the reaction sites between ruthenium and KIO4 and inhibits the corrosion of ruthenium. SDBS was introduced to KIO4-based solution to compensate for the deficiency of MBTA in inhibiting copper corrosion. It has been proved that the coordinated use of MBTA and SDBS can reduce the copper removal rate to about 326 Å min−1 and obtain acceptable surface morphology. The synergistic inhibition mechanism of MBTA and SDBS on copper corrosion can be elucidated as: under the action of KIO4 and mixed inhibitors, a dense and integrated passivating film is generated on the copper surface to inhibit the excessive corrosion of copper. The passivating film is comprised of Cu–MBTA complex, adsorbed SDBS, copper oxides, Cu(IO4)2 and Cu(IO3)2. The results of CMP and ZRA experiments represent that the combination of MBTA and SDBS can adjust the removal rate selectivity of copper, ruthenium and low-κ dielectrics to 1.56:1:1.01 and evidently alleviate the galvanic corrosion of copper.

Effect of ethylenediamine on CMP performance of ruthenium in H2O2-based slurries

“…Compared with slurry A, the addition of EDA in slurry B improves the removal rate of ruthenium, but the removal rate of copper is remarkably higher than that of ruthenium. On this basis, the corrosion inhibitor combination for copper in another study 50 is added (as shown in slurry C), and successfully adjust the removal rate selectivity to 1.13 : 1.…”

Role of Potassium Tolyltriazole as an Inhibitor in H2O2-Based Slurry on Cu/Ru Patterned Wafer CMP

“…There is a stable current between a certain range of potentials, which proves that the corrosion inhibition effect of copper is related to the formation of a protective film. 17,18,[20][21][22][23] The main cathodic reactions were the reactions of oxygen reduction as follows: 23…”

Surface corrosion inhibition effect and action mechanism analysis of 5-methyl-benzotriazole on cobalt-based copper film chemical mechanical polishing for GLSI

“…2, has received a lot of attention as an azole inhibitor. At the same concentration, the inhibition performance of TTA is better than benzotriazole (BTA), and it is easier to be removed in the post-cleaning [21,22]. Yin et al [23] studied the suppressive mechanism of BTA and TTA on the Cu surface by quantum chemical method.…”