DELO Validates Reliability of Adhesives in miniLED Connections, Paving Way for Scalable MicroLED Production

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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, reinforcing the role of adhesives in enabling efficient mass production of miniLEDs and future microLED applications.

Building on its 2024 feasibility study, which proved adhesives capable of reliably establishing electrical and mechanical miniLED connections, DELO 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 180 °C. The connections were then subjected to extended storage tests of up to 500 hours at 85 °C/85 % relative humidity and at 120 °C.

The evaluation included light-on validation, U‑I characteristic measurements, and die-shear testing. Results showed 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 both heat and humidity, which typically 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.

Next steps for miniLED and microLED manufacturing

“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 & 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 DELO will present these findings at MicroLED Connect, the leading global event on microLED technology, taking place in Eindhoven, Netherlands, on September 24–25. Alternatively, the detailed results are available in DELO’s latest white paper:

This new study is one of the many advanced evaluations DELO undertakes each year to anticipate industry needs, in addition to more than 3,000 customer-specific tests. The company’s high-tech adhesive solutions serve global leaders across the semiconductor, automotive, and consumer electronics industries.

Schematic illustration showing the process of miniLED integration on a PCB: before placement, after placement, and with the LED illuminated through adhesive connection (figure: DELO).