Tribology and Lubricants

Korean Tribology Society (한국트라이볼로지학회)
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Effect of Free Abrasives on Material Removal in Lap Grinding of Sapphire Substrate

  • Seo, Junyoung (Department of Mechanical System Engineering, Tongmyong University) ;
  • Kim, Taekyoung (Department of Mechanical System Engineering, Tongmyong University) ;
  • Lee, Hyunseop (School of Mechanical Engineering, Tongmyong University)
  • Received : 2018.09.13
  • Accepted : 2018.11.28
  • Published : 2018.12.31
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Abstract

Sapphire is a substrate material that is widely used in optical and electronic devices. However, the processing of sapphire into a substrate takes a long time owing to its high hardness and chemical inertness. In order to process the sapphire ingot into a substrate, ingot growth, multiwire sawing, lapping, and polishing are required. The lap grinding process using pellets is known as one of the ways to improve the efficiency of sapphire substrate processing. The lap grinding process ensures high processing efficiency while utilizing two-body abrasion, unlike the lapping process which utilizes three-body abrasion by particles. However, the lap grinding process has a high material removal rate (MRR), while its weakness is in obtaining the required surface roughness for the final polishing process. In this study, we examine the effects of free abrasives in lap grinding on the material removal characteristics of sapphire substrate. Before conducting the lap grinding experiments, it was confirmed that the addition of free abrasives changed the friction force through the pin-on-disk wear test. The MRR and roughness reduction rate are experimentally studied to verify the effects of free abrasive concentration on deionized water. The addition of free abrasives (colloidal silica) in the lap grinding process can improve surface roughness by three-body abrasion along with two-body abrasion by diamond grits.

Keywords

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Fig. 1. Scanning electron microscope image of the pellet.

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Fig. 1. Scanning electron microscope image of the pellet.

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Fig. 2. Pin-on-disk wear test system; (a) system setting and (b) prepared pin for experiment.

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Fig. 2. Pin-on-disk wear test system; (a) system setting and (b) prepared pin for experiment.

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Fig. 3. Schematic of lap grinding process (a) and lapgrinding machine (b).

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Fig. 3. Schematic of lap grinding process (a) and lapgrinding machine (b).

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Fig. 4. Friction force with time during pin-on-disk wear test using (a) 20 wt% of abrasive concentration in DIW and (b) DIW only.

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Fig. 4. Friction force with time during pin-on-disk wear test using (a) 20 wt% of abrasive concentration in DIW and (b) DIW only.

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Fig. 5. Change of friction force by the addition of free abrasive during pin-on-disk wear test.

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Fig. 5. Change of friction force by the addition of free abrasive during pin-on-disk wear test.

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Fig. 6. Contact angles of DIW on sapphire surfaces after pin-on-disk wear test using (a) DIW only and (b) 20 wt% of abrasive concentration in DIW.

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Fig. 6. Contact angles of DIW on sapphire surfaces after pin-on-disk wear test using (a) DIW only and (b) 20 wt% of abrasive concentration in DIW.

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Fig. 7. Effect of abrasive concentration on the MRR of sapphire substrate.

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Fig. 7. Effect of abrasive concentration on the MRR of sapphire substrate.

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Fig. 8. SEM images of the surface of pellet after lap grinding experiment.

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Fig. 8. SEM images of the surface of pellet after lap grinding experiment.

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Fig. 9. Change in roughness (Ra) reduction rate as a function of abrasive concentration.

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Fig. 9. Change in roughness (Ra) reduction rate as a function of abrasive concentration.

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Fig. 10. Material removal rate as a function of applied pressure.

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Fig. 10. Material removal rate as a function of applied pressure.

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Fig. 11. Roughness (Ra) reduction rate as a function of applied pressure.

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Fig. 11. Roughness (Ra) reduction rate as a function of applied pressure.

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Fig. 12. Material removal rate as a function of rotating speed.

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Fig. 12. Material removal rate as a function of rotating speed.

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Fig. 13. Roughness (Ra) reduction rate as a function of rotating speed.

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Fig. 13. Roughness (Ra) reduction rate as a function of rotating speed.

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Fig. 14. Material removal mechanism of lap grinding using free abrasive; (a) schematic of pellet-free abrasivesubstrate contact, (b) without free abrasive, (c) low concentration of free abrasive, (d) medium concentration of free abrasive, and (e) high concentration of free abrasive.

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Fig. 14. Material removal mechanism of lap grinding using free abrasive; (a) schematic of pellet-free abrasivesubstrate contact, (b) without free abrasive, (c) low concentration of free abrasive, (d) medium concentration of free abrasive, and (e) high concentration of free abrasive.

Table 1. Experimental condition for lap grinding

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Table 1. Experimental condition for lap grinding

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References

  1. Lee, H., Lee, H., Jeong, H., Choi, H., Lee, Y., Jeong, M., Jeong, H., "Macroscopic and microscopic investigation on chemical mechanical polishing of sapphire wafer," J. Nanosci. Nanotechnol., Vol. 12, No. 2, pp. 1256-1259, 2012. https://doi.org/10.1166/jnn.2012.4679
  2. Zhu, H., Tessaroto, L. A., Sabia, R., Greenhut, V. A., Smith, M., Niesz, D., E., "Chemical mechanical polishing (CMP) anisotropy in sapphire," Appl. Surf. Sci., Vol. 236, Issues 1-4, pp. 120-130, 2004. https://doi.org/10.1016/j.apsusc.2004.04.027
  3. Zhu, H., Niesz, D. E., Greenhut, V. A., "The effect of abrasive hardness on the chemical-assisted polishing of (0001) plane sapphire," J. Mater. Res., Vol. 20, No. 2, pp. 504-520, 2005. https://doi.org/10.1557/JMR.2005.0072
  4. Zhang, Z., Liu, W., Song, Z., Hu, X., "Two-step chemical mechanical polishing of sapphire substrate," J. Electrochem. Soc., Vol. 157, No. 6, pp. H688-H691, 2010. https://doi.org/10.1149/1.3410116
  5. Prochnow, E., Edwards, D. F., "Preparing precision ultrafine sapphire surfaces: a practical method," Appl. Opt., Vol. 25, No. 16, pp. 2639-2640, 1986. https://doi.org/10.1364/AO.25.002639
  6. Niu, X., Liu, Y., Tan, B., Han, L., Zhang, J., "Method of surface treatment on sapphire substrate," Trans. Nonferrous Met. Soc. China, Vol. 16, pp. s732-s734, 2006. https://doi.org/10.1016/S1003-6326(06)60290-2
  7. Hu, X., Song, Z., Pan, Z., Liu, W., Wu, L., "Planarization machining of sapphire wafers with boron carbide and colloidal silica as abrasives," Appl. Surf. Sci., Vol. 255, Issue 19, pp. 8230-8234, 2009. https://doi.org/10.1016/j.apsusc.2009.05.056
  8. Yu, X. X., Sun, G. N., "Study on the growth direction of sapphire single crystal," J. Synth. Crystals, Vol. 35, No. 2, pp. 431-434, 2006. https://doi.org/10.3969/j.issn.1000-985X.2006.02.051
  9. Ehman, M. F., Medellin, D., Forrest, F. F., "Mechanical preparation of sapphire single-crystal surfaces by vibratory techniques," Metallography, Vol. 9, No. 4, pp. 333-339, 1976. https://doi.org/10.1016/0026-0800(76)90059-8
  10. Li, Z. C., Pei, Z. J., Funkenbusch, P. D., "Machining processes for sapphire wafers: a literature review," Proc. IMechE, Part B: J. Eng. Manuf., Vol. 225, pp. 975-989, 2011.
  11. Li, B., Guo, X., Liu, Y., Li, B. C., Wang, D. F., Shen, G. D., "Study on the back lapping and polishing of sapphire-based LED epitaxial wafers," Semicond. Technol., Vol. 30, No. 9, pp. 57-60, 2005. https://doi.org/10.3969/j.issn.1003-353X.2005.09.018
  12. Preston, F. W., "The structure of abraded glass surfaces," Trans. Opt. Soc., Vol. 23, No. 3, pp. 141-164, 1921. https://doi.org/10.1088/1475-4878/23/3/301
  13. Buijs, M., Houten, K. K., "Three-body abrasion of brittle materials as studied by lapping," Wear, Vol. 166, Issue 2, pp. 237-245, 1993. https://doi.org/10.1016/0043-1648(93)90267-P
  14. Wang, X., Lu, C. D., Wen, D. H., "Experimental study on the precision lapping of sapphire substrate," Adv. Mater. Res., Vol. 215, pp. 291-294, 2001.
  15. Kim, H. M., Manivannan, R., Moon, D. J., Xiong, H., Park, J. G., "Evaluation of double sided lapping using a fixed abrasive pad for sapphire substrates," Wear, Vol. 302, Issues 1-2, pp. 1340-1344, 2013. https://doi.org/10.1016/j.wear.2012.11.075
  16. Kim, H. M., Park, G. H., Seo, Y. G., Moon, D. J., Cho, B. J., "Comparison between sapphire lapping processes using 2-body and 3-body modes as a function of diamond abrasive size," Wear, Vol. 332-333, pp. 794-799, 2015. https://doi.org/10.1016/j.wear.2015.02.029
  17. Lee, H., Lee, T., "Material removal model of lap grinding for sapphire substrate based on roughness parameters," Mater. Sci. Forum, Vol. 890, pp. 384-387, 2017. https://doi.org/10.4028/www.scientific.net/MSF.890.384
  18. Zhang, Z., Liu, W., Song, Z., "Particle size and surfactant effects on chemical mechanical polishing of glass using silica-based slurry," Applied Optics, Vol. 49, No. 28, pp. 5480-5485, 2010. https://doi.org/10.1364/AO.49.005480
  19. Park, C., Kim, H., Lee, S., Jeong, H., "The influence of abrasive size on high-pressure chemical mechanical polishing of sapphire wafer," Int. J. Precis. Eng. Manuf.-Green Tech., Vol. 2, No. 2, pp. 157-162, 2015. https://doi.org/10.1007/s40684-015-0020-0
  20. Lee, H. S., Jeong, H. D., Dornfeld, D. A., "Semi-empirical material removal rate distribution model for $SiO_2$ chemical mechanical polishing (CMP) processes," Precision Engineering, Vol. 37, No. 2, pp. 483-490, 2013. https://doi.org/10.1016/j.precisioneng.2012.12.006

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