Flexible Printed Circuit FPC on PET with White Solder Mask

Flexible Printed Circuit FPC on PET with White Solder Mask

(Flexible printed circuits are custom-made products, the picture and parameters shown are just for reference)

General Information

This is a type of dual layer flexible circuit built on PET substrate, 1oz copper weight on each layer. The FPC is coating with white solder mask and immersion gold on pads. The pads are bulged for the printer applications.

FPC Specifications

Features and Benefits

Excellent flexibility;

Reduced PCB volume;

Reduced weight;

Increased reliability

Consistency of assembly;

More than 18+ years of PCB experience;

Customer complaint rate: <1%

Prototype capability;

Volume Production capability

Typical Applications

Capacitive touch screen / panel, Industrial control temperature controller soft board, consumer card reader soft board

Covercoat / Solder Mask

Solder mask in flexible PCB is different from rigid board, it is usually a polyimide film coated on one side with a semi-cured and non-tacky adhesive, we call it covercoat in flexible circuit. It is laminated to the flexible circuit under heat and pressure, so that the copper pattern is fully encapsulated except for the solder pads that are exposed through access holes in the covercoat.

The covercoat production sheet should be cut slightly smaller than the flexible circuit production sheet to avoid premature edge sealing, which could trap air bubbles in the package.

The production sheet for the covercoat is provided with tooling holes in close register with the tooling holes in the production sheet for the flexible circuit. The access holes are usually drilled, but in the case of high-volume production, punching is more cost-effective.

In principle, drilling of the covercoat is accomplished in the same way as when drilling rigid boards, i.e., a number of covercoat sheets are stacked, either 5-up or 10-up. The drilling parameters, however, are somewhat different, because of the polyimide material and the absence of copper foil, which otherwise could have removed some of the heat from the holes being drilled.

When drilling/punching large covercoat production sheets, it is necessary to compensate for the dimensional changes of the flexible circuit production sheet, which can amount to as much as 0.2%.

FPC Capabilities 2022

More Displays of White Flex