6Layers Rigid-Flex PCB

The protective material of the Rigid-Flex PCB outer layer pattern, that is, the solder mask, generally has three types to choose from. The first type is the traditional cover film (Coverlay), which is a direct layer of polyimide material and adhesive. It is laminated with the circuit board that needs to be protected after etching. This kind of cover film requires pre-formed before pressing, exposing the part to be welded, so it cannot meet the requirements of finer assembly. The second type is photosensitive development type cover dry film, After pressing with the laminator, the welding part is leaked through the photosensitive development method, which solves the problem of assembly fineness. The third type is liquid screen printing type covering materials, and thermosetting polyimide materials are commonly used, such as solar PSR-4000 and special solder resist ink for photosensitive development type flexible circuit boards, these materials can better meet the requirements of fine-pi…