Introduction:
The development of flexible and rigid-flex PCB has been following the trend of being more layers, thinner and higher density. This trend will lead to the development of corresponding materials, processing, equipment, and motivate new technologies.
Development Trend of New Materials and New Technologies:
The innovation of flexible printed circuit board has a high dependence on the development of new materials. The innovation of insulating substrates, adhesives, foils, cladding layers, reinforcing substrates and other materials used in flexible PCBs can make the boards develop towards higher performance. Because of the high matching requirement of various materials for the fabrication of flexible printed circuit boards, the diversified material system will provide manufacturers with a variety of choices and combinations. The properties of these materials are mainly reflected in thermal expansion coefficient, water absorption, bending degree and bending life and so on.
The development of new materials and new technologies in the PCB industry always promotes each other. Flexible PCB is more prominent because of its high performance requirements. For example, micro-hole processing technology is one of the core technologies of PCB innovation. In recent years, its development speed is much faster than etching, plating, interconnection and other technologies. In the micro-hole machining process of flexible PCB, the mechanical strength and deformation coefficient of different materials of each layer are usually taken into account to predict the deformation effect caused by the hole making, and finally the precise micro-hole machining is realized.
Development Trend of Rigid-Flex PCB:
Rigid PCB combines the advantages of flexible PCB and rigid PCB and is widely used in electronic products. The development of flexible PCB technology mentioned above is also suitable for the development of rigid PCB technology, and because the performance difference of materials involved in rigid PCB is relatively larger, most of these technical challenges are the choice of material combination in the final analysis. For example, in the process of multiple lamination, the difference in thermal expansion coefficient of each layer material in all directions should be considered, and the denaturation compensation should be carried out in combination with the use of reinforcing and reinforcing plates to achieve high-precision alignment lamination.
At the same time, the structure design of rigid-flex PCB has also been a hot spot in this field. Generally speaking, there are many possible design schemes for rigid-flex PCB with the same function. In the actual design, the reliability of the product, the occupied space, the weight, the difficulty of assembly and other aspects should be considered comprehensively. Combined with the manufacturer's production capacity and material factors, the design optimization should be carried out to select the scheme with the lowest cost. Here are some common rigid-flex PCBs as below.
Conclusion:
The changing trend of flexible PCB towards multi-layer ultra-thin and high-density is bound to drive the corresponding development of upstream materials, processes and equipment, and stimulate the emergence of new technologies.
