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Published: 2019
Author: D.Y.

Related stocks: ​ ZHEN DING Tech. (TW: 4958) , FLEXIUM INTERCONNECT INC. (TW: 6269) , Career Tech. (TW: 6153) , DuPont , Taimide Tech. (TW: 3645) , Kaneka (KKA) , UBE , MGC , SKPI (KOSDAQ: 178 920), Sumitomo (TYO: 4005), Murata , Kuraray , CO-TECH DEVELOPMENT (TW: 8358) , Nan Ya (TW: 1303) , TAIFLEX Scientific Co. (TW: 8039) , Rogers , ThinFlex Corporation (TW: 3144)

Flexible Printed Circuit Part 1

What is a FPC?

In Taiwan, we have a dense electronics industry, and the entire industry is very complete. In particular, more than half of the weighted value of Taiwan stocks are electronic stocks. In the entire electronics industry, there are motherboards, passive components, ICs, and flip-chip substrates. , Printed circuit boards, etc., have many companies participating in it and have become the leaders in the industry. Today we will discuss an inconspicuous but very important component for all kinds of electronic products ─ ─ FPC.

Flexible PCB VS. Rigid PCB

Among the printed circuit boards, it is mainly divided into Rigid board RPCB, flexible board FPC, and Rigid-flexible board. The rigid board is the main substrate of the motherboard in the computer. In many reports, printed circuit boards or PCBs are also referred to as rigid boards. The flexible board is a board used to connect many components. For example, in a mobile phone, an antenna flexible board is generally required to connect the antenna to the mainboard. Generally, the flexible board is required to be connected because it can be bent, concave, and thin, so in space, when components are far away, use flexible boards to connect.

Rigid Board
印刷電路板 PCB
Flexible board
軟板 FPC

​ Next, let’s refer to the comparison chart to make everyone better understand the difference between flexible and rigid boards. Most of the companies that produce flexible boards and rigid boards are different, because there are many technical differences between the two, and it also increases manufacturers’ entry into the gap. The threshold of the board, although most manufacturers currently hope to expand the product line in different fields, currently no manufacturer can stand firm in the flexible board and rigid board industries at the same time. Compared with the rigid board, the technical threshold of a flexible board is higher. Therefore, in the field of the rigid-flexible board, flexible board manufacturers have more advantages.

Regid Flexible PCB Comparison.jpg

Application of FPC

The application of FPC is very wide. It can be said that as long as it is used in technology products, the largest application of FPC is smartphones. According to QY Research, the use of FPC in smartphones accounts for about 40% of the total FPC. In addition, there are also laptops, automotive electronics, medical, military, and wearable devices. In the pursuit of lightness, thinness, and shortness in modern products, FPC has also become very important. According to statistics, the number of FPC used by iPhone X accounted for about 20 pieces, and it is expected that the number of phones 11 launched in 2019 will reach 27 pieces. There are so many FPC used in a terminal device, and this FPC is used in the terminal equipment The roles played are as follows: antenna FPC, backlight module FPC, camera lens FPC, touch screen FPC, Fingerprint IC FPC, SIM card FPC, laptop screen connecting FPC, car image sensor test FPC, the FPC of the car lamp group, etc., from this we can see the importance of the FPC.

Types of FPC

FPC is divided into PI, MPI, LCP according to the material. MPI is the modified PI. PI is almost eliminated because of its poor performance. Now the main materials used for FPC are MPI and LCP, and the performance of LCP is higher than MPI. The relative price has also increased significantly. In terms of performance to cost, it is generally believed that MPI is higher. Especially in recent years, the performance of MPI has been greatly improved, which further threatens LCP. Just as Apple decided to replace some LCP soft boards with MPI soft boards in 2018. reduce costs. The biggest consideration factor in the use of the three types of soft boards is transmission loss. There is no significant difference in the loss of the three in the case of low-frequency transmission, but as the frequency increases, the loss of PI gradually increases, and MPI and LCP also have a greater loss in loss difference. Therefore, in the case of higher frequencies, the advantages of LCP will be more obvious. It can be seen that in the 5G era, some transmission frequencies will be greatly increased to above 24GHz, and there will be higher requirements for the quality of flexible boards. Taiwan's three major FPC manufacturers, ZHEN DING Tech., FLEXIUM INTERCONNECT INC., and Career Tech, also have their main strengths. For example, ZHEN DING and FLEXIUM INTERCONNECT two kinds of  FPC are actively investing in bilateral betting to avoid missing business opportunities, but the main force is still MPI; on the contrary; Yes, Career Tech focuses on LCP development. Detailed analysis of each manufacturer will be announced in Part 3.


FPC type.jpg

Fabrication of FPC

Like other substrates, FPC pursues higher linear density and number of layers to improve FPC performance and reduce transmission power consumption. However, the manufacturing process of FPC is very complicated, and the technical capabilities required in electronic components are relatively Higher, and therefore it is not easy for companies to enter the FPC industry. In addition, the manufacturing process of FPC requires a lot of chemicals, so it is a highly polluting industry. Especially when the environmental protection awareness of various countries is gradually increasing, the environmental protection cost of FPC manufacturers is also higher. In recent years, the Industrial Technology Research Institute and other institutions have continued to invest in research and development of automated production technology in order to enhance the competitiveness of Taiwan’s FPC industry, hoping to convert the previously relatively labor-intensive FPC industry to a high degree of automation, thereby reducing labor costs.

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