The high curing temperatures required for traditional benzocyclobutene (BCB) materials have posed limitations on their applicability in high-temperature-sensitive fields. To address this challenge, our work focuses on the synthesis of a novel tetraphenylethylene (TPE)-functionalized BCB monomer, TPE-BCB, achieved through the introduction of an ether bond onto the BCB’s four-membered ring via Williamson reaction. TPE-BCB demonstrates remarkable low-temperature curing properties, characterized by a ring-opening peak temperature of 190 °C, representing a 25% reduction compared to conventional BCBs. Fully cured TPE-BCB resins exhibit exceptional dielectric and mechanical properties, coupled with minimal water absorption. Additionally, the incorporation of TPE with aggregation-induced emission (AIE) characteristics enhances the resins’ luminescence and photolithographic capabilities. Notably, our TPE-BCB resins achieve impressive photolithography performance with a resolution ratio of up to 10 µm. In contrast to conventional BCB-functionalized resins, TPE-BCB offers the dual advantage of low-temperature curing and luminescence. This development marks a significant step in the advancement of low-temperature curing BCB materials and serves as a pioneering example in the realm of multi-layer wafer bonding materials.

It’s urgent to develop benzocyclobutene (BCB)-based polymers with low curing temperatures for temperature-sensitive applications such as liquid crystal display (LCD) and flexible electronics. Herein, the effect of substituents on the ring-opening behavior of BCB derivatives was investigated. The ring-opening activation energy barriers (ΔGA) of BCB derivatives with one or two substituents on the four-membered alkyl ring were systematically calculated using the B3LYP function. Both mono- and di-substituted BCBs adopted the conrotatory ring-opening process, obeying the Woodward-Hoffmann’s Rules upon heating. The mono-/di-substituted BCBs ex-hibited 8.2 – 69% lower ΔGA compared with BCB, attributed to the electronic effects of the substituents. Disubstituted BCBs with both electron-donating and electron-withdrawing groups, e.g., 1-NH2-8-NO2-BCB, demonstrated the lowest ΔGA. In addition, BCB derivatives with amide/ester/acyloxy group modified on C1 position were synthesized as model molecules, and their ring-opening temperature can be decreased by 20 °C compared to the unsubstituted one, also consistent with our calculation results. This work combined the theoretical calculation method with experimental results to provide valuable insights into the design and synthesis of BCB derivatives and next-generation BCB functional packaging materials with low ring-opening temperatures.