Wafer‐Scale Micro‐LEDs Transferred onto an Adhesive Film for Planar and Flexible Displays
Wafer‐Scale Micro‐LEDs Transferred onto an Adhesive Film for Planar and Flexible Displays
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DOI：
10.1002/admt.202000549
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发表时间：
2020-08
影响因子：
6.8
通讯作者：
Z. Pan;Chan Guo;Xianchi Wang;Jiucheng Liu;Ruimin Cao;Y. Gong;Jiantai Wang;Ningyang Liu;Zhitao Chen;Lihui Wang;M. Ishikawa;Z. Gong
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文献类型：
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作者：
Z. Pan;Chan Guo;Xianchi Wang;Jiucheng Liu;Ruimin Cao;Y. Gong;Jiantai Wang;Ningyang Liu;Zhitao Chen;Lihui Wang;M. Ishikawa;Z. Gong
微型发光二极管（LED）显示器的发展推动了微型LED巨量转移技术的研究。迄今为止，提出了各种转移技术，但是在转移良率和转移精度方面仍然存在很大的改进空间。此外，这些技术是否适用于后续的键合工艺尚未得到充分研究，而这对于在 Micro-LED 和驱动电子器件之间实现良好的电连接至关重要。这里开发了一种称为“带辅助激光转移”的系统解决方案，它不仅适用于高产量的 micro-LED 转移，而且与后续的键合工艺也很好兼容。该方法使用低成本胶带作为支撑基板，基于激光剥离 (LLO) 工艺，可实现 micro-LED 的快速晶圆级转移，具有极高的良率 (约 99.8%) 和最小化的转移位移 (<0.5 µm)。与荫罩相结合，LLO 工艺还可以选择性地将 micro-LED 转移到胶带上。这种薄膜 Micro-LED 与随后使用低熔点焊料的“无凸点”接合工艺非常兼容。包括平面显示器和可变形显示器在内的代表性显示设备得到进一步开发，表明该方法在开发应用于 VR/AR、可穿戴设备和智能眼镜的高分辨率 Micro-LED 显示面板方面具有良好的潜力。
The development of micro‐sized light emitting diode (LED) displays has driven the research of micro‐LED mass‐transfer technology. To date, various transfer technologies are proposed, but ample room for improvements in the transfer yield and transfer accuracy still remains. Furthermore, whether these techniques are suited for the subsequent bonding process is not well investigated, which is essential for achieving a good electric connection between micro‐LEDs and driver electronics. Here a systematical solution, termed as “tape‐assisted laser transfer,” which is not only suited for high‐yield micro‐LED transfer but also well compatible with subsequent bonding process, is developed. Using a low‐cost adhesive tape as the support substrate, the method allows fast and wafer‐level transfer of micro‐LED with extremely high yield (≈99.8%) and minimized transfer displacement (<0.5 µm), based on a laser lift‐off (LLO) process. Combined with a shadow mask, the LLO process also allows the selective transfer of micro‐LED to the tape. Such thin film micro‐LEDs are well compatible with the subsequent “bumpless” bonding process using low‐melting point solder. Representative display devices including planar display and deformable display are further developed, suggesting the method has a good potential for developing high‐resolution micro‐LED display panels for the applications in VR/AR, wearables, and smart glasses.