Development of Low-Dielectric Modified Polyimide with Low-Temperature Radical Curing for High-Frequency Flexible Printed Circuit Boards

This study presents the development of a modified polyimide (MPI) with low dielectric properties and low-temperature curing capability for high-frequency flexible printed circuit boards (FPCBs). MPI was cured using dicumyl peroxide (DCP) at 80–140 °C through a radical process optimized via DSC analy...

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Bibliographic Details
Main Authors: Seonwoo Kim, Suin Chae, Mirae Seo, Yubin Kim, Soobin Park, Sehoon Park, Hyunjin Nam
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Micro
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Online Access:https://www.mdpi.com/2673-8023/5/2/23
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Summary:This study presents the development of a modified polyimide (MPI) with low dielectric properties and low-temperature curing capability for high-frequency flexible printed circuit boards (FPCBs). MPI was cured using dicumyl peroxide (DCP) at 80–140 °C through a radical process optimized via DSC analysis, while Fourier-transform infrared (FT-IR) confirmed the elimination of C=C bonds and the formation of imide structures. The MPI film exhibited low dielectric constants (D<sub>k</sub>) of 1.759 at 20 GHz and 1.734 at 28 GHz, with ultra-low dissipation factors (D<sub>f</sub>) of 0.00165 and 0.00157. High-frequency S-parameter evaluations showed an excellent performance, with S11 of −32.92 dB and S21 of approximately −1 dB. Mechanical reliability tests demonstrated a strong peel strength of 0.8–1.2 kgf/mm (IPC TM-650 2.4.8 standard) and stable electrical resistance during bending to ~6 mm radius, with full recovery after severe deformation. These results highlight MPI’s potential as a high-performance dielectric material for next-generation FPCBs, combining superior electrical performance, mechanical flexibility, and compatibility with low-temperature processing.
ISSN:2673-8023