All-Hydrocarbon Low-Dielectric Loss Benzocyclobutene-Encapsulated Photoresist with High Pattern Resolution

Abstract

UV-curable resins with a low dielectric constant can be processed or patterned to form required shapes, making them highly applicable to special fields. Unlike conventional photoresists limited by the polarization effect due to highly polar bonds, an all-hydrocarbon-type low-dielectric photoresist was designed and synthesized with excellent performance. Based on previous works, the film-forming resin poly 1-(4-vinylphenyl)-2-(4-benzocyclobutenyl)ethylene-styrene (P-DVB-St) was prepared by introducing styrene (St) into the 1-(4-vinylphenyl)-2-(4-benzocyclobutenyl)ethene (DVB) backbone via anionic polymerization, and the photoresist properties were improved by adjusting the cross-linking density of the polymer. The introduction of styrene improved the mechanical properties while maintaining the photolithographic patterning properties of the photoresist. Since the resin has a dual UV/thermal-cured structure, it has better thermal stability (T_5% = 401 °C), lower dielectric constant (2.62 at 10 MHz) and dielectric loss (1.7 × 10^–3), and better photolithographic patterning (the graphic resolution is 5 μm).