Effect of Free Abrasives on Material Removal in Lap Grinding of Sapphire Substrate
1
조회
0
다운로드
2
인용
0
참고문헌
키워드
초록
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.
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.
참고문헌 (20)
- Lee, H., "Macroscopic and microscopic investigation on chemical mechanical polishing of sapphire wafer", J. Nanosci. Nanotechnol, 12(2), pp.1256~1259 (2012)
- Zhu, H., "Chemical mechanical polishing(CMP)anisotropy in sapphire", Appl. Surf. Sci., 236(1-4), pp.120~130 (2004)
- Zhu, H., "The effect of abrasive hardness on the chemical-assisted polishing of(0001)plane sapphire", J. Mater. Res, 20(2), pp.504~520 (2005)
- Zhang, Z., "Two-step chemical mechanical polishing of sapphire substrate", J. Electrochem. Soc., 157(6), pp.H688~H691 (2010)
- Prochnow, E., "Preparing precision ultrafine sapphire surfaces : a practical method", Appl. Opt, 25(16), pp.2639~2640 (1986)
- Niu, X., "Method of surface treatment on sapphire substrate", Trans. Nonferrous Met. Soc. China, 16, pp.s732~s734 (2006)
- Hu, X., "Planarization machining of sapphire wafers with boron carbide and colloidal silica as abrasives", Appl. Surf. Sci., 255(19), pp.8230~8234 (2009)
- Yu, X. X., "Study on the growth direction of sapphire single crystal", J. Synth. Crystals, 35(2), pp.431~434 (2006)
- Ehman, M. F., "Mechanical preparation of sapphire single-crystal surfaces by vibratory techniques", Metallography, 9(4), pp.333~339 (1976)
- Li, Z. C., "Machining processes for sapphire wafers : a literature review", Proc. IMechE, Part B : J. Eng. Manuf, 225, pp.975~989 (2011)
- Li, B., "Study on the back lapping and polishing of sapphire-based LED epitaxial wafers", Semicond. Technol, 30(9), pp.57~60 (2005)
- Preston, F. W., "The structure of abraded glass surfaces", Trans. Opt. Soc, 23(3), pp.141~164 (1921)
- Buijs, M., "Three-body abrasion of brittle materials as studied by lapping", Wear, 166(2), pp.237~245 (1993)
- Wang, X., "Experimental study on the precision lapping of sapphire substrate", Adv. Mater. Res, 215, pp.291~294 (2001)
- Kim, H. M., "Evaluation of double sided lapping using a fixed abrasive pad for sapphire substrates", Wear, 302(1-2), pp.1340~1344 (2013)
- Kim, H. M., "Comparison between sapphire lapping processes using 2-body and 3-body modes as a function of diamond abrasive size", Wear, 332-333, pp.794~799 (2015)
- Lee, H., "Material removal model of lap grinding for sapphire substrate based on roughness parameters", Mater. Sci. Forum, 890, pp.384~387 (2017)
- Zhang, Z., "Particle size and surfactant effects on chemical mechanical polishing of glass using silica-based slurry", Applied Optics, 49(28), pp.5480~5485 (2010)
- 박철진, "The Influence of Abrasive Size on High-Pressure Chemical Mechanical Polishing of Sapphire Wafer", International Journal of Precision Engineering and Manufacturing-Green Technology, 2(2), pp.157~162 (2015), 한국정밀공학회
- Lee, H. S., "Semiempirical material removal rate distribution model for SiO 2chemical mechanical polishing(CMP)processes", Precision Engineering, 37(2), pp.483~490 (2013)