Enhanced reliability of phosphor-converted white light-emitting diodes based on a laser-cured silicone encapsulant layer. (October 2022)

• Record Type: Journal Article
• Authors: Lee, Yu Seong; Kim, Yu Kyung; Kim, Jae Pil; Yun, Changhun
• Is Part Of: Microelectronics and reliability. Volume 137(2022)
• Publication Date: 2022-10
• Subjects: Light emitting diodes -- Packaging -- Phosphors -- Laser -- Encapsulation -- Reliability engineering; Electronic apparatus and appliances -- Reliability -- Periodicals; Miniature electronic equipment -- Periodicals; Appareils électroniques -- Fiabilité -- Périodiques; Équipement électronique miniaturisé -- Périodiques; Electronic apparatus and appliances -- Reliability; Miniature electronic equipment; Periodicals; 621.3815
• DOI: 10.1016/j.microrel.2022.114756
• Languages: English
• ISSNs: 0026-2714

Abstract

Abstract: The laser-induced heating method was implemented for the homogeneous curing process of silicone encapsulant layer in phosphor-converted white light-emitting diodes (pc-WLEDs). Using the curing process with infrared laser irradiation, we demonstrated that pc-WLEDs performed better in the highly accelerated temperature and humidity stress test (85 °C, 85 Rh%) and the sulfur exposure test than devices with convection oven curing. The results from FTIR spectra, dynamic mechanical analysis, and Brunauer-Emmett-Teller (BET) surface area analysis indicated that the enhanced reliability of the laser-cured device could be attributed to the lower permeation property of gas molecules inside the laser-cured encapsulant layer. In addition, the permeation mechanism in the encapsulant layer of pc-WLED was proposed based on the cross-linking density of a silicone polymer and the total pore volumes in the phosphor-mixed encapsulant layer. Highlights: Reliability enhancement in phosphor-converted white light-emitting diodes Long lifespan in high temperature and high moisture environments Laser-assisted curing process for silicone encapsulant layer Low permeability of reactive gases due to the uniform and high degree of cure of silicone