Electroless deposition of high-uniformity nickel microbumps with ultrahigh resolution of 8 μm pitch for monolithic Micro-LED display
Journal article, 2024
Micro-light-emitting diode (Micro-LED) displays have attracted growing attention due to their unsurpassed properties that satisfy the requirements of reality/virtual reality (AR/VR) displays. A crucial procedure of monolithic integration technology in high-density microdisplays is the interconnection process, which is intimately associated with the quality of the display device. Microfluidic electroless interconnection (MELI), an innovative low-temperature and pressure-free chip-stacking approach that eliminates the warpage-induced issues and cracking damage of the chip caused by thermo-compression bonding (TCB), holds great promise as a technology for establishing interconnections between the CMOS driver and Micro-LED. However, the requirement for the consistency of the microbump arrays and the risk of creating bridges is significantly intensified with smaller gaps in stacked chips, which restricts the application range of MELI to high-density interconnects. This paper analyzes the feasibility of further lowering the stand-off height of stacked chips in ultrafine pitch interconnects by optimizing the bump preparation process. The plasma modification time and surfactant concentration during the bump preparation process have been investigated. The result indicated that microbump arrays with a uniformity of less than 3% could be successfully manufactured by employing a 7-min plasma treatment and incorporating optimal surfactants, which catalyzes the implementation of the subsequent vertical interconnection process and eventually enhances yields of Micro-LEDs.
Ultrafine pitch
High uniformity
Micro-LED display
Ni microbumps
Electroless plating
Author
Yu Lu
Fuzhou University
Chang Lin
Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China
Fuzhou University
Liang Tian
Fuzhou University
Shuaishuai Wang
Fuzhou University
Kaixin Zhang
Fuzhou University
Taifu Lang
Fuzhou University
Yang Li
Fuzhou University
Qiwei Li
Fuzhou University
Tianxi Yang
Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China
Zhonghang Huang
Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China
Jie Sun
Fuzhou University
Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Qun Yan
Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China
Fuzhou University
Materials Science in Semiconductor Processing
1369-8001 (ISSN)
Vol. 175 108263Subject Categories
Other Materials Engineering
Other Electrical Engineering, Electronic Engineering, Information Engineering
DOI
10.1016/j.mssp.2024.108263