Can underfill materials improve optical packaging without adding heat during assembly? A dual-cure formulation aims to simplify the process.
YINCAE Advanced Materials has introduced UF 66UV, a dual-cure underfill developed for optoelectronic, photonic and semiconductor packaging applications requiring high optical clarity, mechanical reliability and low-temperature processing. The material combines ultraviolet (UV) and thermal curing to simplify the assembly of delicate optical components while maintaining performance under demanding operating conditions.
The underfill is designed for advanced optical packages where conventional heating during dispensing can affect sensitive components. By flowing into ultra-fine gaps at room temperature, UF 66UV eliminates the need for initial heating during assembly. The exposed material is then rapidly fixed using UV curing, while a subsequent thermal cure at 60°C completes polymerisation in shadowed regions, ensuring full encapsulation and long-term mechanical stability.
According to YINCAE, the cured material delivers more than 98% visible light transmittance and maintains optical transparency throughout environmental reliability testing. The company reported that the underfill retained its optical transmission after Pressure Cooker Test (PCT) exposure and five lead-free reflow cycles at 260°C, with no measurable loss in light transmission, visible yellowing or degradation in adhesion. These characteristics make the material suitable for applications where optical efficiency and package reliability are critical.
UF 66UV is intended for use in MicroLED displays, CMOS image sensors, optical sensors, silicon photonics, VCSEL and LiDAR modules, AR/VR optical assemblies, as well as medical and industrial optical devices. The material’s combination of room-temperature flow, dual-cure processing and high optical stability is designed to support packaging requirements across emerging photonics and semiconductor technologies.
“Advanced optical packaging demands materials that combine fast processing, excellent optical clarity, and long-term reliability,” says a YINCAE spokesperson. “UF 66UV addresses these requirements with room-temperature flow, rapid UV fixation, low-temperature thermal curing, and exceptional resistance to moisture and high-temperature reflow without compromising optical performance.”
Click here for the official announcement.
