Study of Geopolymer Adhesive Bonding with Alumina Ceramics for DUV LED Packaging

In the post-pandemic era of the pandemic, there has been a significant increase in the focus on disinfection methods, leading to a surge in demand for deep ultraviolet (DUV) light-emitting diodes (LEDs). Geopolymers offer a viable solution to the reliability challenges faced by conventional organic materials when exposed to DUV radiation. This research delves into the bonding mechanisms of geopolymer adhesives used with alumina substrates in DUV LED packaging. Through mechanical, rheological, and microscopic analyses, we identify the optimal geopolymer formulation—comprising metakaolin and water glass with a silicate modulus of 1.9 at a mass ratio of 5:8—that exhibits superior bonding strength, suitable workability, and homogeneous geopolymerization. XRD, FTIR and SEM are employed to assess the geopolymerization degree in terms of material composition and chemical bonding. TEM reveals the bonding mechanism of the geopolymer with the alumina substrate. While geopolymerization occurs at the interface, the reaction intensity here is lower than that within the bulk of the geopolymer. This study enhances our understanding of geopolymer interactions in composite materials and contributes to advancements in electronic device packaging technologies.