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Potassium persulfate as an oxidizer in chemical mechanical polishing slurries relevant for copper interconnects with cobalt barrier layers

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Abstract

Cobalt (Co) has been applied as one of the most promising candidates of barrier metals for copper (Cu) interconnects. The present work describes the static etching and chemical mechanical polishing process of Cu and Co, which were conducted by potassium persulfate (K2S2O8) as an oxidizer at various pH values. It was found that compared with the conventional oxidizer hydrogen peroxide (H2O2)-based slurries, the K2S2O8-based slurries exhibited a relatively high Co removal rate, as well as the diminished particulate contamination and excellent post-etching morphology. A slurry consisting of 3 vol% colloidal silica, 10 mM K2S2O8, and 5 mM benzotriazole (BTA) produced a Co removal rate of ~ 127 Å/min at pH 10, along with a removal rate selectivity of ~ 1 between Cu and Co films. Based on the data of X-ray photoelectron spectroscopy, scanning electron microscopy, and nano-scratch depth tests, the interplaying mechanisms of chemical and mechanical on Cu and Co removal rates in K2S2O8-based slurries were investigated.

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References

  1. Wong HSP (2005) Beyond the conventional transistor. Solid State Electron 49(5):755–762

    Article  CAS  Google Scholar 

  2. T Nogami et al (2010) CVD Co and its application to Cu damascene interconnections. In: 2010 IEEE international interconnect technology conference IITC 2010, vol 111, pp 10–12

  3. Yang CC et al (2012) Co capping layers for Cu/low-k interconnects. Microelectron Eng 92:79–82

    Article  CAS  Google Scholar 

  4. Bekiaris N et al (2017) Cobalt fill for advanced interconnects. In: IITC 2017–2017 IEEE international interconnect technology conference. pp 1–3

  5. Huang HY et al (2010) A new enhancement layer to improve copper interconnect performance. In: 2010 IEEE international interconnect technology conference, vol 3, pp 1–3

  6. Li Z, Gordon RG, Farmer DB, Lin Y, Vlassak J (2005) Nucleation and adhesion of ALD copper on cobalt adhesion layers and tungsten nitride diffusion barriers. Electrochem Solid State Lett 8(7):G182–G185

    Article  CAS  Google Scholar 

  7. Xu W-Z, Xu J-B, Lu H-S, Wang J-X, Hu Z-J, Qu X-P (2013) Direct copper plating on ultra-thin sputtered cobalt film in an alkaline bath. J Electrochem Soc 160(12):D3075–D3080

    Article  CAS  Google Scholar 

  8. He M et al (2013) Mechanism of Co liner as enhancement layer for Cu interconnect gap-fill. J Electrochem Soc 160(12):D3040–D3044

    Article  CAS  Google Scholar 

  9. CRC handbook of chemistry and physics: a ready-reference book of chemical and physical data. Choice Reviews Online, vol 29, no. 01. pp 29-0016–29-0016 (1988)

  10. Jiang L, He Y, Li Y, Li Y, Luo J (2014) Synergetic effect of H2O2 and glycine on cobalt CMP in weakly alkaline slurry. Microelectron Eng 122:82–86

    Article  CAS  Google Scholar 

  11. Popuri R et al (2017) Citric acid as a complexing agent in chemical mechanical polishing slurries for cobalt films for interconnect applications. ECS J Solid State Sci Technol 6(9):P594–P602

    Article  CAS  Google Scholar 

  12. Ranaweera CK, Baradanahalli NK, Popuri R, Seo J, Babu SV (2019) Ammonium persulfate and potassium oleate containing silica dispersions for chemical mechanical polishing for cobalt interconnect applications. ECS J Solid State Sci Technol 8(5):P3001–P3008

    Article  CAS  Google Scholar 

  13. Nishizawa H, Nojo H, Isobe A (2010) Fundamental study of chemical–mechanical polishing slurry of cobalt barrier metal for the next-generation interconnect process. Jpn J Appl Phys 49(5 PART 3):4–6

    Google Scholar 

  14. Peethala BC, Amanapu HP, Lagudu URK, Babu SV (2012) Cobalt polishing with reduced galvanic corrosion at copper/cobalt interface using hydrogen peroxide as an oxidizer in colloidal silica-based slurries. J Electrochem Soc 159(6):582–588

    Article  Google Scholar 

  15. Lu H-S et al (2012) The effect of H2O2 and 2-MT on the chemical mechanical polishing of cobalt adhesion layer in acid slurry. Electrochem Solid State Lett 15(4):H97–H100

    Article  CAS  Google Scholar 

  16. Sagi KV, Teugels LG, Van Der Veen MH, Struyf H, Alety SR, Babu SV (2017) Chemical mechanical polishing of chemical vapor deposited Co films with minimal corrosion in the Cu/Co/Mn/SiCOH patterned structures. ECS J Solid State Sci Technol 6(5):P276–P283

    Article  CAS  Google Scholar 

  17. Turk MC, Shi X, Gonyer DAJ, Roy D (2016) Chemical and mechanical aspects of a Co–Cu planarization scheme based on an alkaline slurry formulation. ECS J Solid State Sci Technol 5(2):P88–P99

    Article  CAS  Google Scholar 

  18. Tsai TH, Wu YF, Yen SC (2005) Glycolic acid in hydrogen peroxide-based slurry for enhancing copper chemical mechanical polishing. Microelectron Eng 77(3–4):193–203

    Article  CAS  Google Scholar 

  19. Poddar MK et al (2019) Nanocatalyst-induced hydroxyl radical (OH) slurry for tungsten CMP for next-generation semiconductor processing. J Mater Sci

  20. Cui H, Park JH, Park JG (2013) Effect of oxidizers on chemical mechanical planarization of ruthenium with colloidal silica based slurry. ECS J Solid State Sci Technol 2(1):26–30

    Article  Google Scholar 

  21. Lee WJ, Park HS (2004) Development of novel process for Ru CMP using ceric ammonium nitrate (CAN)-containing nitric acid. Appl Surf Sci 228(1–4):410–417

    Article  CAS  Google Scholar 

  22. Kim IK et al (2008) Effect of sodium periodate in alumina-based slurry on Ru CMP for metal-insulator-metal capacitor. Electrochem Solid State Lett 11(6):150–153

    Article  Google Scholar 

  23. Shirley DA (1972) High-resolution x-ray photoemission spectrum of the valence bands of gold. Phys Rev B 5(12):4709–4714

    Article  Google Scholar 

  24. Foelske A, Strehblow HH (2000) Passivity of cobalt in borate buffer at pH 9.3 studied by X-ray photoelectron spectroscopy. Surf Interface Anal 29(8):548–555

    Article  CAS  Google Scholar 

  25. Sun Y et al (2013) Electrodeposited cobalt-sulfide catalyst for electrochemical and photoelectrochemical hydrogen generation from water. J Am Chem Soc 135(47):17699–17702

    Article  CAS  Google Scholar 

  26. Ismail KM, Badawy WA (2000) Electrochemical and XPS investigations of cobalt in KOH solutions. J Appl Electrochem 30(11):1303–1311

    Article  CAS  Google Scholar 

  27. Miller AC, Simmons GW (1993) Copper by XPS. Surf Sci Spectra 2(1):55–60

    Article  CAS  Google Scholar 

  28. Galtayries A, Bonnelle J-P (1995) XPS and ISS studies on the interaction of H2S with polycrystalline Cu, Cu2O and CuO surfaces. Surf Interface Anal 23(3):171–179

    Article  CAS  Google Scholar 

  29. Du T, Luo Y, Desai V (2004) The combinatorial effect of complexing agent and inhibitor on chemical–mechanical planarization of copper. Microelectron Eng 71(1):90–97

    Article  CAS  Google Scholar 

  30. Lee WJ et al (2002) Adhesion and interface chemical reactions of Cu/polyimide and Cu/TiN by XPS. Appl Surf Sci 205(1–4):128–136

    Google Scholar 

  31. Varghese B, Yousheng Z, Ling D, Tan VBC, Chwee TL, Sow CH (2008) Structure-mechanical property of individual cobalt oxide nanowires. Nano Lett 8(10):3226–3232

    Article  CAS  Google Scholar 

  32. Karimpoor AA, Erb U, Aust KT, Palumbo G (2003) High strength nanocrystalline cobalt with high tensile ductility. Scr Mater 49(7):651–656

    Article  CAS  Google Scholar 

  33. Aledresse A, Alfantazi A (2004) A study on the corrosion behavior of nanostructured electrodeposited cobalt. J Mater Sci 39(4):1523–1526. https://doi.org/10.1023/B:JMSC.0000013934.85378.40

    Article  CAS  Google Scholar 

  34. Badawy WA, Al-Kharafi FM, Al-Ajmi JR (2000) Electrochemical behaviour of cobalt in aqueous solutions of different pH. J Appl Electrochem 30(6):693–704

    Article  CAS  Google Scholar 

  35. Anipsitakis GP, Dionysiou DD (2003) Degradation of organic contaminants in water with sulfate radicals generated by the conjunction of peroxymonosulfate with cobalt. Environ Sci Technol 37(20):4790–4797

    Article  CAS  Google Scholar 

  36. Yao Y, Xu C, Qin J, Wei F, Rao M, Wang S (2013) Synthesis of magnetic cobalt nanoparticles anchored on graphene nanosheets and catalytic decomposition of orange II. Ind Eng Chem Res 52(49):17341–17350

    Article  CAS  Google Scholar 

  37. Ji Y, Dong C, Kong D, Lu J (2015) New insights into atrazine degradation by cobalt catalyzed peroxymonosulfate oxidation: kinetics, reaction products and transformation mechanisms. J Hazard Mater 285:491–500

    Article  CAS  Google Scholar 

  38. Zhang L, Wang T, Lu X (2019) The effect of citric acid based cleaning solution on particle adhesion and removal during post-Cu CMP cleaning. Microelectron Eng 216:111090

    Article  CAS  Google Scholar 

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Acknowledgements

The authors would like to thank the financial support of National Natural Science Foundation of China (Grand No. 51991374).

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  1. State Key Laboratory of Tribology, Tsinghua University, Beijing, 100084, China

    Lifei Zhang, Tongqing Wang & Xinchun Lu

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  1. Lifei Zhang
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  2. Tongqing Wang
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Correspondence to Xinchun Lu.

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Zhang, L., Wang, T. & Lu, X. Potassium persulfate as an oxidizer in chemical mechanical polishing slurries relevant for copper interconnects with cobalt barrier layers. J Mater Sci 55, 8992–9002 (2020). https://doi.org/10.1007/s10853-020-04579-6

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