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Abnormal redeposition of silicate from Si3N4 etching onto SiO2 surfaces in flash memory manufacturing

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Abstract

The Si3N4 layers in a 3D NAND flash patterned wafer are generally removed by hot phosphoric acid. However, the abnormal deposition of silicate which is the by-product from Si3N4 etching onto the neighboring SiO2 layers will cause a serious problem in the subsequent process. In this work, the abnormal deposition phenomenon was investigated by a simple system containing a narrow gap (~ 80 μm) between two blanket wafers. To understand the mechanism, the influences of various factors on the chemical etching dynamics were examined, including the water content and the extent of mechanical agitation. It is found that the growth rate of SiO2 decreases as the water content or the extent of agitation is increased. Our experimental results reveal that the abnormal growth on SiO2 layers is a consequence of the competition between chemical deposition and mass transfer in a confined space (reaction–diffusion system).

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References

  1. Cho S et al (2012) Development of high selectivity phosphoric acid and its application to flash STI pattern. Electrochem Soc Trans 45:251–256

    CAS  Google Scholar 

  2. Derek B, Printz W, Furukawa T (2015) Etching of silicon nitride in 3D NAND structures. Electrochem Soc Trans 69:159–167

    Google Scholar 

  3. Hong et al (2015) Compositions for etching and methods of forming a semiconductor device. United States patent US8940182B2

  4. Yu TY, Su YS, Hsu LT, Liang JL, Yeh SC, Su PC (2009) Method and system for improving wet chemical bath process stability and productivity in semiconductor manufacturing. United States patent US20090087929A1

  5. Seo D, Sung SJ, Oh SBE, Kim S, Lim S (2014) Selective wet etching of Si3N4/SiO2 in phosphoric acid with the addition of fluoride and silicic compounds. Microelectron Eng 118:66–71

    Article  CAS  Google Scholar 

  6. Derek WB, Antonio LPR (2016) Silica formation during etching of silicon nitride in phosphoric acid. In: SSP, vol 255, pp 285–290

  7. Glenn WG (2018) Industry context for semiconductor wet etch and surface preparation. In: Solid state phenomena, vol 282, pp 3–9

  8. Gelder WV, Hauser VE (1967) The etching of silicon nitride in phosphoric acid with silicon dioxide as a mask. J Electrochem Soc 114:869–872

    Article  Google Scholar 

  9. Chang YH, Hu CC, Yang CM (2018) A design for selective wet etching of Si3N4/SiO2 in phosphoric acid using a single wafer processor. J Electrochem Soc 165:H3187–H3191

    Article  Google Scholar 

  10. Fogler HS (2005) Elements of chemical reaction engineering, 3rd edn. Prentice Hall, Englewood Cliffs

    Google Scholar 

  11. Buttet C et al (2015) Alternative to H3PO4 for Si3N4 removal by using chemical downstream etching. Electrochem Soc Trans 64:1–9

    Google Scholar 

  12. Morita K, Ohnaka K (2000) Novel selective etching method for silicon nitride films on silicon substrates by means of subcritical water. Ind Eng Chem Res 39:4684–4688

    Article  CAS  Google Scholar 

  13. Morosanu CE (1980) The preparation, characterization and applications of silicon nitride thin films. Thin Solid Films 65:171–208

    Article  CAS  Google Scholar 

  14. Paul WM, Marc M, Marc H (2016) Silica formation during etching of silicon nitride in phosphoric acid. In: SSP, vol 255, pp 285–290

  15. Chien VC, Yang CM, Hu CC (2019) The etching of silicon nitride in phosphoric acid with novel single wafer processor. In: IEEE, vol 18888741, pp 2376–6697

  16. Long X et al (2016) Reactive hot pressing and mechanical properties of B4C/Li2O–Al2O3–SiO2 composites. J Non-Cryst Solids 432:510–518

    Article  Google Scholar 

  17. Huang CC et al (2017) Magnetic property enhancement of cobalt-free M-type strontium hexagonal ferrites by CaCO3 and SiO2 addition. Intermetallics 89:111–117

    Article  Google Scholar 

  18. Shigeru TE et al (2015) Plasma processing method and manufacturing method of semiconductor device United States patent US9177781B2

  19. Kim KH et al (2017) Substrate treating apparatus and method of treating substrate United State patent US9852921B2

Download references

Acknowledgements

The authors thank the Ministry of Science and Technology of Taiwan (Grant No. 108-2622-E-008-003-CC2) for financial support.

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Authors and Affiliations

  1. Department of Chemical and Materials Engineering, National Central University, Jhongli, 320, Taiwan, ROC

    Kai-Wen Teng, Sheng-Hung Tu, Ssu-Wei Hu, You-Xin Huang & Heng-Kwong Tsao

  2. Department of Chemical Engineering, National Taiwan University, Taipei, 106, Taiwan, ROC

    Yu-Jane Sheng

  3. Department of Physics, National Central University, Jhongli, 320, Taiwan, ROC

    Heng-Kwong Tsao

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  1. Kai-Wen Teng
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  2. Sheng-Hung Tu
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  3. Ssu-Wei Hu
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Correspondence to Yu-Jane Sheng or Heng-Kwong Tsao.

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Teng, KW., Tu, SH., Hu, SW. et al. Abnormal redeposition of silicate from Si3N4 etching onto SiO2 surfaces in flash memory manufacturing. J Mater Sci 55, 1126–1135 (2020). https://doi.org/10.1007/s10853-019-04119-x

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  • DOI: https://doi.org/10.1007/s10853-019-04119-x

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