Last year, we posted that adhesive developer and MicroLED Association member DELO has conducted in-house feasibility studies, that shows that their directional conductive adhesives can be used to replace soldering in miniLED, and microLED displays. The bonding was found to be reliable with high yields.
DELO has continued its miniLED project, and has now announced that it has examined their durability over extended test periods. The company says that it has shown that directional conductive adhesives are not only technically feasible for miniLEDs but also reliable in long-term conditions that realistically reflect industrial environments. The company believes that adhesives could play a role in microLED display production as well.
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.
DELO will present these findings at our MicroLED Connect 2025 event which will take place in Eindhoven, Netherlands, on September 24–25. You can also download the company's white paper with detailed results here.
