Enabling flexible copper-clad laminates via silver-assisted patterning on sequence-defined low dielectric polyimide

Polyimides are widely used in the manufacture of flexible copper-clad laminates because of their excellent thermal stability, mechanical properties, and solvent resistance. However, copper-clad laminates based on fully aromatic polyimide substrates suffer from electronic signal propagation delay and signal loss during operation, issues that become particularly pronounced under high-frequency signal transmission. Additionally, the traditional subtractive process used to fabricate copper-clad circuits on polyimide film surfaces has significant drawbacks, including high energy consumption and environmental pollution. Therefore, developing low-dielectric polyimides and additive manufacturing methods for flexible copper-clad laminates remains a major challenge. Here, controllable regulation of segment sequence structure and segment length in silicon-oxygen polyimide was achieved through a stepwise polymerization strategy. The resulting block polyimide exhibits excellent comprehensive performance, with a dielectric constant as low as 2.76 and an initial thermal decomposition temperature of 489 °C. By combining laser direct writing with additive patterning, controllable copper metallization based on a silver seed layer was successfully achieved on the surface of the block polyimide films. The copper wires, composed of cubic-phase copper nanoparticles with grain sizes of 70-90 nm, display high-resolution edge definition and excellent mechanical stability. This synergistic approach, integrating controllable polymer synthesis with surface metal patterning, provides an effective alternative method for manufacturing high-performance flexible electronic devices.