Thanks to the comprehensive advantages of PCB boards and FPC boards, rigid-flex boards have been widely used in electronic products. In addition, since the rigid-flex board involves more material differences, all technical challenges mainly come from the selection of material combinations. For example, in a multiple lamination process, the CTE difference in each direction of each layer of material should be carefully considered and used together with a reinforcement plate so that high-precision alignment lamination can be achieved for deformation compensation.
At the same time, the structural design of rigid-flex boards is also a hot spot in its development. Generally speaking, there may be many design options for rigid-flex boards with equivalent functions. The actual design should start from a comprehensive consideration, including product reliability, occupied space, weight and assembly complexity. In addition, for an optimal design with minimal procurement procedures, the manufacturer's manufacturing capabilities and material elements should be considered. For example, common 3-layer to 8-layer rigid-flex boards can utilize CCL copper-clad laminates with or without adhesion. Similarly, the covering layer of the flexible area in the rigid-flex board has a different structure.
Another research and development trend of rigid-flex boards lies in the manufacture of component-embedded PCBs. In most cases, it is required to perform embedding of resistors and capacitors in rigid regions without compromising the performance of flexible regions. For the second time, this application places stringent demands on the material. In addition, flexible PCBs can work normally on CSP chip-scale packaging technology, while the component-embedded PCB structure poses challenges and requirements for packaging technology.
