Biobased and Negative-Type Photosensitive Polyimides with Low Dielectric Constant and Dissipation Factor Formulated by Using a Photobase Generator

Photosensitive polyimides (PSPIs) are vital in modern electronics, combining exceptional thermomechanical stability with photopatterning capabilities. This unique combination enables PSPIs to effectively address the challenges of fabricating high-density, miniaturized devices, ensuring reliable performance in advanced electronic systems. Current research has made significant progress in enhancing PSPIs’ thermal stability, optical transparency, and lithographic precision, further expanding their applicability. However, most PSPIs rely heavily on petrochemical-derived monomers, raising sustainability concerns as fossil fuel resources decline. This study focuses on developing biobased PSPIs as a sustainable alternative, aiming to advance the concept of biobased and low-CO₂ emission materials. By using isosorbide as a biomass source and incorporating monomers with low-dielectric and distinct functional groups─fluorine-ester, fluorine-ether, and both symmetric and asymmetric ester groups─the goal is to achieve a low dielectric constant and low dissipation factor while exploring their impact on dielectric properties. The PSPI is formulated using a photobase generator. The decreased dissolution rate in the i-line exposed area is associated with increased imidization attributed to the base-catalyzed imidization assisted by piperidine released from the photobase after light exposure and postexposure baking. Therefore, a high-performance, negative-type, and biobased PSPI can be obtained. Through this approach, this study seeks to balance high-performance characteristics with environmental sustainability. This will ultimately result in PSPIs with a high biomass content that offer excellent thermal, mechanical, and dielectric properties, paving the way for greener, more sustainable materials in next-generation electronic devices.