Adhesives validated in miniLED connections pave the way for scalable microLED production

DELO has conducted extensive reliability tests on directional conductive adhesives, confirming their suitability as a robust alternative to solder in miniLED display manufacturing. The recent study focused on the long-term performance of adhesive connections under demanding temperature and humidity storage conditions, supporting the role of adhesives in facilitating efficient mass production of miniLEDs and future microLED applications.

Building on its 2024 feasibility study, which demonstrated that adhesives are capable of reliably establishing electrical and mechanical miniLED connections, the company has now examined their durability over extended test periods. Using stamping to dispense precise adhesive volumes onto structured test boards, single and arrayed miniLEDs were cured with a thermode process at 180C. The connections were then subjected to extended storage tests of up to 500 hours at 85C/85% relative humidity and at 120C.

The evaluation included light-on validation, U‑I characteristic measurements, and die-shear testing. Results demonstrated stable mechanical strength and excellent electrical performance over time, closely matching the specifications from the LED data sheets, even after prolonged exposure to elevated heat. A critical test scenario combined heat and humidity, which generally challenges solder-based connections. Even under the most demanding conditions, directional conductive adhesives remained reliable, underscoring their suitability as a robust connection technology for next-generation displays.

"These results show that directional conductive adhesives are not only technically feasible for miniLEDs but also reliable in long-term conditions that realistically reflect industrial environments," said Maximilian Baum, director Product Management Consumer Assembly and Equipment at DELO. "With these findings, adhesives move from a feasibility concept to a validated connection technology, one that both refines miniLED production and accelerates the transition to mass-market microLED displays."

Experts from the company will present these findings at MicroLED Connect, taking place in Eindhoven, Netherlands, on September 24–25. Alternatively, the detailed results are available via the 'Learn more' link on this page.