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http://dx.doi.org/10.9725/kts.2022.38.3.93

A Study on Selective Transfer and Reflow Process of Micro-LED using Micro Stamp  

Han, Seung (Dept. of Nano-Mechatronics, University of Science and Technology (UST))
Yoon, Min-Ah (Dept. of Mechanical Engineering, University of Science and Technology (UST))
Kim, Chan (Div. of Nano-Convergence Manufacturing Systems Research, Korea Institute of Machinery and Materials (KIMM))
Kim, Jae-Hyun (Dept. of Mechanical Engineering, University of Science and Technology (UST))
Kim, Kwang-Seop (Dept. of Mechanical Engineering, University of Science and Technology (UST))
Publication Information
Tribology and Lubricants / v.38, no.3, 2022 , pp. 93-100 More about this Journal
Abstract
Micro-light emitting diode (micro-LED) displays offer numerous advantages such as high brightness, fast response, and low power consumption. Hence, they are spotlighted as the next-generation display. However, defective LEDs may be created due to non-uniform contact loads or LED alignment errors. Therefore, a repair process involving the replacement of defective LEDs with favorable ones is necessitated. The general repair process involves the removal of defective micro-LEDs, interconnection material transfer, as well as new micro-LED transfer and bonding. However, micro-LEDs are difficult to repair since their size decreases to a few tens of micron in width and less than 10 ㎛ in thickness. The conventional nozzle-type dispenser for fluxes and the conventional vacuum chuck for LEDs are not applicable to the micro-LED repair process. In this study, transfer conditions are determined using a micro stamp for repairing micro-LEDs. Results show that the aging time should be set to within 60 min, based on measuring the aging time of the flux. Additionally, the micro-LEDs are subjected to a compression test, and the result shows that they should be transferred under 18.4 MPa. Finally, the I-V curves of micro-LEDs processed by the laser and hot plate reflows are measured to compare the electrical properties of the micro-LEDs based on the reflow methods. It was confirmed that the micro-LEDs processed by the laser reflow show similar electrical performance with that processed by the hot plate reflow. The results can provide guidance for the repair of micro-LEDs using micro stamps.
Keywords
Micro-LED; Micro stamp; Repair process; Selective transfer process; Laser reflow;
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1 Kim, C., Yoon, M.-A., Jang, B., Kim, J.-H., Lee, H.-J., Kim, K.-S., "Ultimate Control of Rate-Dependent Adhesion for Reversible Transfer Process via a Thin Elastomeric Layer", ACS Appl. Mater. Interfaces, Vol.9, 12886-12892, 2017.   DOI
2 Behrman, K., Fouilloux, J., Ireland, T., Fern, G., Silver, J., Kymissis, I., "Micro LED Defect Analysis via Photoluminescent and Cathodoluminescent Imaging" SID Display Week Virtual Conference, San Francisco, USA, August 2020.
3 Meitl, M., Zhu, Z.-T., Kumar, V., Lee, K. J., Feng, X., Huang, Y. Y., Adesida, I., Nuzzo, R. G., Rogers, J. A., "Transfer printing by kinetic control of adhesion to an elastomeric stamp", Nature Materials, Vol.5, pp.33-38., 2006.   DOI
4 Jang, B., Kim, C.-H., Choi, S., Kim, K.-S., Kim, K.-S., Lee, H.-J., Cho, S., Ahn, J.-H., Kim, J.-H., "Damage mitigation in roll-to-roll transfer of CVD-graphene to flexible substrates", 2D Mater., Vol.4, 024002, 2017.   DOI
5 Day, J., Li, J., Lie, D., Bradford, C., Lin, J., Jiang, H., "III-nitride full-scale high-resolution microdisplays", Appl. Phys. Lett., Vol.99, pp.031116, 2011.   DOI
6 Choi, M., Jang, B., Lee, W., Lee, S., Kim, T. W., Lee, H. J., Kim J.-H., Ahn, J. H., "Stretchable active matrix inorganic light-emitting diode display enabled by overlay-aligned roll?transfer printing", Adv. Funct. Mater., Vol.27, pp.1606005, 2017.   DOI
7 Lewis, D., Dechter, R., Ley, R., Wong, M., Khoury, M., "Overcoming the Challenges in microLED Inspection and Manufacturing", International Conference on Display Technology(ICDT), Beijing, China, May 2021.
8 Wang, W., Yang, W., Wang, H, Li, G., "Epitaxial growth of GaN films on unconventional oxide substrates" J. Mater. Chem. C, Vol.2, pp.9342-9358, 2014.   DOI
9 Liu, L., Edgar, J. H., "Substrates for gallium nitride epitaxy", Materials Science and Engineering R, Vol.37, pp.61-127, 2002.   DOI
10 Ding, K., Avrutin, V., Izyumskaya, N., Ozgur, U., Morkoc, H., "Micro-LEDs, a Manufacturability Perspective" Appl. Sci., Vol.9, Issue 6, pp.1206, 2019.   DOI
11 Sheng, C., Wang, Y., Dong, X., Li, M., Wang, C., Huang, X., Ge, Y., "A Study on Micro-LED Selective Repair Technology for Mass Production Purpose" International Conference on Display Technology (ICDT), Beijing, China, May 2021.
12 Prevatte, C., Radauscher, E., Meitl, M., A., Gomez, D., Ghosal, K., Bonafede, S., Raymond, B., Moore, T., Trindade, A., J., Hines, P., Bower, C., A., "Miniature Heterogeneous Fan-Out Packages for High-Performance, Large-Format Systems", IEEE 67th Electronic Components and Technology Conference, Florida, USA, June 2017.
13 Chen, Z., Yan, S., Danesh, C., "MicroLED technologies and applications:characteristics, fabrication, progress, and challenges" J. Phys. D: Appl. Phys., Vol.54, pp.123001, 2021.   DOI
14 Sa, K.-d., Micro LED repair process, Korea Photonics Technology Institute, KR Patent No. 10-2021-0012980.
15 Meitl, M., Radauscher, E., Bonafede, S., Gomez, D., Moore, T., Prevatte, C., Raymond, B., Fisher, B., Ghosal, K., Fecioru, A., Trindade, A., Kneeburg, D., Bower, C., "Passive Matrix Displays with Transfer-Printed Microscale Inorganic LEDs", SID International symposium, San Francisco, USA, May 2016.