PCB Tech - The FPC soft board market demand has increased greatly with the change of smart mobile devices

Mobile devices continue to shrink the product size, coupled with the surge in demand for wearable devices, the original use of PCB has been greatly integrated in the direction of small size and high density. In order to meet the requirements of product institutions, the proportion of the use of soft boards for circuit substrates is increasing. The higher the performance of the flexible substrate will affect the integration and durability of the product...

In recent years, due to the drastic changes in the global market, the sales of desktop computers and notebook computers that originally used PCBs have slowed down, even if the commercial host computer will stop supporting the old operating system at Microsoft, stimulating the replacement of PC/NB for commercial use. However, the overall sales and gross profit are still inferior to smartphones and tablet computer products. It is not only PCB usage and trends that directly follow the market demand to produce corresponding changes. Wearable smart products, which have increased in popularity in the market in 2014, are more important for PCBs. The demand is more compact and compact, and even requires a large number of flexible printed circuits(FPC) to match the product integration requirements.

Electronic product demand evolves, FPC soft board applications increase

The demand for flexible circuit boards is not only high for wearable smart products, but also for tablet computers and smart phone products. Because 3C electronic devices continue to be thinner, smaller, and more mobile. FPC is a flexible circuit board. Generally, a PCB circuit board is a layer of glass fiber substrate coated with copper foil material, so that the circuit board has the basic thickness and hardness, and is used to weld integrated circuits and electronic components on the substrate. Although traditional PCBs continue to improve with high density and multilayer, PCBs still occupy more space and are less flexible in use. The flexible circuit board has flexible characteristics, which can effectively construct the space of the internal circuit carrier board, and can also make the electronic product more suitable for the design direction of light, thin, short and small.

As for the PCB circuit board, it needs to meet the requirements of thinning and adapt to the environment of small-space packaging, and even take into account the requirements of high speed and high heat conduction. Among them, for thinning and high-density packaging requirements, the flexible circuit board is more rigid than the rigid PCB. The advantages of good use, and the new type of flexible circuit boards are also targeted at high-speed, high thermal conductivity, 3D wiring, high-flexibility assembly and other value-added advantages, which can better respond to the requirements of flexible construction products for wearable applications, allowing soft The related market demand for modular circuit boards continues to increase.

Soft board is suitable for special configuration purposes

In order to meet the needs of special configuration or flexible structure design, the original rigid PCB structure certainly cannot meet the product design requirements. Even if the flexible circuit board cannot meet the full application, at least the product design will not affect the core circuit. The required small size and thin PCB, matched with a flexible circuit board, uses 3D wiring to connect other functional modules in series, or connect key batteries, sensors and other components, while the function of the flexible circuit board to completely replace the hard circuit board is not yet possible Full replacement applications, but with flexible circuit boards trying to introduce thinner substrates (copper foil, substrates, substrates), touch (conductive ink), high heat resistance (substrates, substrates, adhesives), and low electric current The integration of material technology such as high efficiency and low electric current, photosensitive PI, 3D three-dimensional (base material, substrate) shape, and transparency (base material, substrate) also makes the market application of flexible circuit boards more diverse and more practical.

The evolution of soft board material technology follows the demand of 3C/IT product manufacturing

Summarizing the development trajectory of flexible circuit boards, in fact, it corresponds to the development trend of smart phones, tablet computers, and even novel wearable smart devices. The development of different flexible circuit board materials technology is mostly improved in response to the needs of terminal products. Research and development.

Depending on the complexity of its structure, flexible circuit boards are mainly divided into single-sided, double-sided and multilayer flexible circuit boards. The application range can be in personal computer products (tablet computers, notebook computers, printers, hard disk drives, optical disc drives), Displays (LCD, PDP, OLED), consumer electronics (digital cameras, cameras, audio, MP3), automotive electrical components (dashboards, audio, antennas, function controls), electronic instruments (medical instruments, industrial electronic instruments) ), communication products (smart phones, fax machines), etc., with a wide range of applications,

As the application of FPC gradually penetrates into automotive electronics, or other circuit connection applications that require high-temperature operation mechanisms, the heat resistance performance of FPC becomes increasingly important. Because of the material relationship, the early products have more restrictions on heat resistance performance. However, the successive application of novel material technology to FPC has also made the application of FPC relatively expanded. For example, Polyimide material has good heat resistance and material strength, and it has also begun to be used in products with high body temperature.

Thinning and 3D FPC meets the demand of novel 3C product configuration

Although FPC has extremely thin characteristics, compared with the thickness of PCB, the thickness of flexible circuit board is much thinner, and the thickness of conventional workpiece is only 12~18μm. The purpose of using FPC is in addition to the flexibility of the carrier board. In addition to making the circuit more adaptable to the configuration constraints of the terminal design, the thickness of the FPC workpiece is also an important focus of attention. Generally, the common manufacturing method is to use the rolled copper foil to deal with the FPC thinning requirements, or directly electrolysis on the carrier board. The extreme thinness of the material, but the thickness of conventional workpieces is about 12μm, and there is also a micro-etched copper thinning process for ultra-thinning requirements, which can make FCB thinner, but can maintain the basic electrical performance of conventional products, But the relative material cost will also increase.

Another larger trend is to support three-dimensional configuration FPC products. Three-dimensional configuration FPC can make the soft board into wavy, spiral rotation, concave-convex and curved surfaces. In the three-dimensional configuration, 3D FPC is another It needs to achieve the self-retaining characteristics of the appearance, which can also be called low reaction force, that is, the shape of the soft plate after three-dimensional forming will not return to a flat shape due to the elasticity of the material itself and the stress of the copper foil. This type of three-dimensional FPC The material technology is even more superb.

As for the three-dimensional configuration of the FPC, there are many uses, such as the connection line of the robot arm. The complex structure of the internal circuit of the robot arm and the special wiring requirements at the joints can be met through the variable three-dimensional configuration. It is also used for automated production equipment and medical equipment., Optical equipment is also quite common, especially in response to the special needs of any connection application.

Even as the awareness of environmental protection is gradually rising, FPC also needs to pay attention to the material manufacturing process that meets environmental protection requirements. At the same time, it also needs to meet product requirements such as mechanical stress, heat resistance, and chemical resistance. Japanese FPC manufacturers have introduced water-soluble PI products, with higher environmental protection requirements than general FPC, provide electronic product manufacturers with more environmentally friendly FPC options, and how acceptable is the new style of water-soluble PI applications? Still to be tested by the market.