Controlling the Removal Rate Selectivity of Ruthenium to Copper during CMP by Using Guanidine Carbonate and 1, 2, 4-Triazole

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.

Section: Sdbs (Ppm) E Corr (V) I Corr (A Cmmentioning

confidence: 99%

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

Tan

et al. 2020

“…19 K Yadav et al 20 revealed that the Ru RR reached approximately 200 Å min −1 when using sodium hypochlorite as the oxidant in a titania-based slurry with a pH of 9, but the RR was still lower. Qing Wei Wang et al 21 proposed a guanidine salt as a complexing agent to improve the RR of Ru, which suggested that Ru-Gnd complexes were formed between guanidine ions and Ru in the slurry with hydrogen peroxide (H 2 O 2 ) as the oxidant. Liang Jiang and Zi Yan Wang et al 22,23 improved the RR of Ru by adding potassium ions (K + ) and ammonium ions (NH 4 + ) into the slurry, and K + and NH 4…”

mentioning

confidence: 99%

Role of Diethylene Triaminepentaacetic Acid Pentapotassium Salt on Ruthenium CMP in H₂O₂-Based Slurries

Zhou

Wang

et al. 2022

Self Cite

As technology is scaled down to 5 nm or even smaller, ruthenium (Ru) will most likely be chosen as the next generation barrier material for copper interconnects in integrated circuits (ICs). Recently, the higher removal rate of Ru barrier materials in chemical mechanical polishing (CMP) has become a major issue. In this paper, diethylene triaminepentaacetic acid pentapotassium salt (DTPA-5K) was introduced as a new complexing agent in a hydrogen peroxide (H2O2)-based alkaline slurry with the goal of increasing the Ru removal rate (RR) during chemical mechanical polishing (CMP). The synergy of H2O2 and DTPA-5K significantly improved the RR of Ru to 412 Å/min. Various analytical results, including electrochemical, X-ray photoelectron spectroscopy, Raman experiments, atomic force microscopy and confocal microscope data, revealed that the RR of Ru can be improved by reducing electrostatic repulsion and also by forming Ru-DTPA complexes.

“…However, serious corrosion will occur when polishing the pattern wafer, which is a serious problem. The another one is adding a complexing agent to the H 2 O 2 -based slurry system, Ziyan Wang 16 studied the effect of ammonium complexing agent, Liang Jiang 17 studied the effect of potassium ions, and Yichen Du 18 and Qingwei Wang 19 et al studied the effect of guanidinium ions. The results show that, on the one hand, the added cation can weaken the electrostatic repulsion between the silica particles and the Ru surface, and on the other hand, complexing agent can produce a complex reaction, which is the enhancement of the Ru removal rate.…”

mentioning

confidence: 99%

Effect of UV Radiation on Oxidation for Ru CMP

Wang

et al. 2021

Self Cite

As feature size continue to decrease, traditional copper (Cu) interconnections will encounter many problems. Ruthenium (Ru) is selected as a barrier material and even a future interconnection metal material because of its many advantages. However, due to its high hardness and chemical inertness, Ru is difficult to be removed during chemical mechanical polishing (CMP). In this study, the effect of UV-activated potassium persulfate (K2S2O8) on the removal rate of Ru CMP was studied. X-ray photoelectron spectroscopy (XPS) combined with electrochemistry is used to study the removal mechanism and chemical reactions. The results show that ultraviolet rays can enhance the chemical action in the CMP process and change the removal rate. Under the condition of 80 mM, the promotion rate is about 28.01%. When the particle diameter increases to 80 nm, the removal rate is also significantly increased by about 26.36%. Mechanism analysis shows that, on the one hand, it is affected by diffusion-control. On the other hand, the surface RuO3 and K2S2O8 undergo a Fenton-like reaction under UV conditions, which makes the Ru surface loose and porous (Rq = 0.533 nm), so it is easier to remove under mechanical action.