Views：1081 Date：2020-05-09

FPC flexible boards are generally divided into single-layer boards, double-layer boards, multi-layer boards, double-sided boards, etc.

The structure of FPC single-layer flexible board: the flexible board with this structure is the flexible board with the simplest structure. Generally, the base material + transparent glue + copper foil is a set of purchased raw materials, and the protective film + transparent glue is another purchased raw material. First, copper foil should be etched and processed to obtain the required circuit, and the protective film should be drilled to expose the corresponding pad. After cleaning, the two are combined by rolling. Then, gold or tin is plated on the exposed pad part for protection. In this way, the big board is ready. Generally, a small circuit board with a corresponding shape is punched. There is also a solder mask layer printed directly on the copper foil without a protective film, so the cost will be lower, but the mechanical strength of the circuit board will be poor. Unless the strength requirements are not high but the price needs to be as low as possible, it is best to apply a protective film.

The structure of the FPC double-layer flexible board: When the circuit of the circuit is too complicated, the single-layer board cannot be routed, or copper foil is required for grounding shielding, it is necessary to select a double-layer board or even a multi-layer board. The most typical difference between a multi-layer board and a single-layer board is the addition of a via structure in order to connect the various layers of copper foil. The first processing technology of general substrate + transparent glue + copper foil is to make vias. First drill holes in the base material and copper foil, after cleaning, plate a certain thickness of copper, and the vias are ready. The subsequent manufacturing process is almost the same as the single-layer board.

FPC double-sided flexible board structure: Both sides of the double-sided board have pads, which are mainly used for connection with other circuit boards. Although it is similar in structure to a single-layer board, the manufacturing process varies greatly. Its raw material is copper foil, protective film + transparent glue. First drill holes in the protective film according to the requirements of the position of the pad, and then paste the copper foil, and then etch the pad and the lead, and then paste another protective film drilled.