Development of high-performance naphthalene-based bismaleimide resins via enhanced π-π stacking: Achieving superior mechanical properties and low CTE

Leverage π–π stacking to design naphthalene-based bismaleimide resins. • Achieve high Tg and excellent thermal stability for electronic packaging. • Realize ultralow CTE combined with high modulus. • Deliver high mechanical strength in glass-fiber composites. With the rapid development of advanced electronic packaging technologies towards thinner, higher density integration, and long-term reliability, substrate materials for packaging are facing increasingly stringent requirements. Particularly, as device integration increases, the bonding between chips and packaging substrates becomes tighter, making the insufficient rigidity and mismatch in coefficient of thermal expansion (CTE) of the packaging substrates more pronounced. Consequently, developing substrate resin systems with both high rigidity and low CTE has become a focal point of current research. This paper starts from molecular structure design and successfully synthesizes a bis-maleimide resin rich in naphthalene rings (2,7-BMPN). The strong π-π stacking interactions between naphthalene rings significantly enhance the intermolecular forces within the cured resin network. Research results indicate that due to the tight molecular packing and enhanced rigidity brought by π-π stacking, the prepared BPMN resin blends exhibits excellent comprehensive performance: the glass transition temperature (T g ) of the pure resin reaches up to 335.4 °C, while the flexural modulus and strength of the fiberglass composite plate reach 40.5 GPa and 588.3 MPa respectively, significantly surpassing traditional bismaleimide systems. Moreover, the dense cross-linking structure effectively restrains segmental thermal motion, reducing the CTE to 6.7 ppm/K, showcasing exceptional dimensional stability. Additionally, this resin contributes significantly to lowering dielectric loss, achieving a minimum value of 0.00762 at 5 GHz. In summary, this high-performance BPMN resin constructed via the π-π stacking strategy demonstrates significant potential in the application of copper-clad laminate (CCL) core materials for advanced electronic packaging due to its outstanding mechanical strength, low thermal expansion characteristics, and overall superior performance. Download: Download high-res image (285KB) Download: Download full-size image