With the rapid advancement of display and smart lighting technologies, micro-light-emitting diodes (Micro-LEDs) have garnered substantial attention due to their exceptional performance characteristics. However, a significant challenge persists in achieving reliable interconnections between Micro-LED chips and driver backplanes. This article proposes and implements the Double-Layer Photoresist Structure Electroplating (DPSE) technique for fabricating Cu-SnAg metal bumps, thereby facilitating the heterogeneous integration of oxide thin film transistors (TFTs) with GaN-based blue LEDs. The DPSE process was optimized by addressing several critical factors, including the correlation between bump height and electroplating time, the occurrence of cracks in the photoresist surface, and the removal of the conductive layer. Metal bumps were successfully fabricated on TFT backplanes with dimensions of 16.5 μm × 10 μm, an average height of 5.39 μm, and a uniformity of approximately 2.266%. To demonstrate the efficacy of this approach, a 0.495-inch blue active-matrix Micro-LED display was designed and fabricated. This display features a mesa size of 15 µm × 30 µm, a pixel pitch of 222 µm, and a pixel density of 114 pixels per inch (PPI). The resultant blue Micro-LED display exhibits excellent optical characteristics, achieving a brightness of 1625 cd/m² (nits). It is anticipated that the methodology and findings presented in this study will contribute significantly to the advancement of Micro-LED display technology in consumer electronics. This research not only represents a significant advancement in the field of Micro-LED display technology, but also paves the way for future innovations in high-resolution, energy-efficient display systems.

中文翻译：

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有源矩阵 TFT 驱动的 GaN 蓝光 Micro-LED 显示器采用基于电镀铜-锡-银微凸块的键合结构实现


随着显示器和智能照明技术的飞速发展，微型发光二极管 （Micro-LED） 因其卓越的性能特性而受到广泛关注。然而，在 Micro-LED 芯片和驱动器背板之间实现可靠的互连仍然存在重大挑战。本文提出并实施了双层光刻胶结构电镀 （DPSE） 技术，用于制造 Cu-SnAg 金属凸块，从而促进了氧化物薄膜晶体管 （TFT） 与基于 GaN 的蓝光 LED 的异构集成。DPSE 工艺通过解决几个关键因素进行了优化，包括凸块高度和电镀时间之间的相关性、光刻胶表面裂纹的发生以及导电层的去除。在 TFT 背板上成功制造了尺寸为 16.5 μm × 10 μm、平均高度为 5.39 μm、均匀性约为 2.266% 的金属凸块。为了证明这种方法的有效性，设计并制造了一种 0.495 英寸蓝色有源矩阵 Micro-LED 显示器。该显示器的台面尺寸为 15μm × 30μm，像素间距为 222μm，像素密度为每英寸 114 像素 （PPI）。由此产生的蓝色 Micro-LED 显示器表现出出色的光学特性，亮度达到 1625cd/m²（尼特）。预计本研究中提出的方法和发现将为消费电子产品中 Micro-LED 显示技术的进步做出重大贡献。这项研究不仅代表了 Micro-LED 显示技术领域的重大进步，而且为高分辨率、高能效显示系统的未来创新铺平了道路。