4 Layer Flexible PCB Production Record #FPC-20260819-026

The manufacturing of these 25 four-layer flexible PCBs centered on a 0.2 mm thickness using 1/3 oz rolled copper. Measuring 59.8 x 65.5 mm, the boards required 4/4 mil minimum track and spacing together with 0.2 mm holes. Yellow soldermask, white silkscreen, and immersion gold ENIG surface finish were applied without stiffeners, preserving the inherent flexibility of the polyimide construction.

We performed careful polyimide material handling prior to inner layer imaging, circuit etching, and layer stack alignment. High pressure lamination bonded the layers before coverlay application and yellow solder mask processing. Electroless nickel and immersion gold depositions created the ENIG finish while maintaining trace definition on the thin substrate.

Dynamic flex testing and electrical testing verified consistent mechanical endurance and circuit integrity across all boards. The 12.9-day production window supported precise execution of each process step, delivering uniform quality that matched the specified parameters for this multilayer flexible design.