Fujikura Ltd.

Internal Wiring Component

It is a technology platform developed from the founding business of our company, "Electric wire and cable". We are developing a variety of internal wiring components that will contribute to the advancement of electronic devices, such as smartphones, which are essential to the daily lives of people today.

Planar Wiring Technology

This technology is related to "Planar Wiring Component" in Technology Platform "Internal Wiring Component". Our company possesses multiple technologies that enable it to propose products that meet customer needs, such as "FPC (Flexible Printed Circuit)" "membrane" and "Wafer And Board level device Embedded Technology".

Related technology

FPC (Flexible Printed Circuit)

FPC (Flexible Printed Circuit)

In FPC, we are developing products and technologies focusing on mobile and electronic devices, which have long been our main markets, and responding to the growing needs of the automotive market.

Mobile Phones and Electronic Devices

We are working on the development of fine pitch FPC to accommodate with the evolution of electronic information equipment, and high frequency high speed transmission FPC for increasing data transmission speed such as 5G.

<Fine pitch technology>

We are currently in the developing a semi-additive process for the formation of fine pitch circuits for mass production of L/S = 10/10 μm. (See Photo 1)

<High frequency and high speed transmission FPC>

We are developing FPCs for internal wiring and antenna substrates for millimeter-wave bands (28 GHz) that use materials with low permittivity and low dielectric loss tangent that are compatible with 5G. (See Photo 2.) 

Photo 1: Semi-additive Circuit Photograph (L/S = 10/10 μm)

Photo 2: High-speed transmission FPC

(Integrated USB and antenna feeding type)


As the use of FPCs for automotive applications continues to expand, we are developing FPCs to meet the needs for new functions and performance.

<High Heat-Dissipation FPC>

Among LED lighting applications in automobiles, for headlamp applications with high output, it is necessary to efficiently dissipate the heat generated by LEDs. (See Photo 3.)

<Dissimilar metal bonding technology>

With the aim of applying it to high-current applications using aluminum stiffener used in FPCs as current paths, we have achieved a joint that suppresses the formation of intermetallic compounds in the welding of copper and aluminum using our proprietary welding method with a fiber laser manufactured in-house. (See Photo 4 and Figure 1)

Photo 3: LED Mounted High Heat-Dissipation FPC

Photo 4: Welded area of copper/aluminum plate

Figure 1: Weld Section Overview



Fujikura provides membrane wiring board whose circuits are by screen-printing a conductive ink onto polyester film or the other substrates. Recently wearable devices are spotlighted as useful equipment to monitor vital signal for sport player and/or health care, then we are under developing a stretchable membrane which can make electrical circuits directly onto stretchable fabric material. Our conductive ink is designed as not easily absorbed into fabric, optimized stretchable and tough, then it can endure 10,000 cycles of 10% stretching test. It is expected to be useful technology such as medical, health care, and sports activity field.

Stretchable circuits onto fabric/wear (Stretching part : Elbow)

Cross-section view

Stretching test result

Wafer And Board level device Embedded Technology

Wafer And Board level device Embedded Technology

An Embedded die substrate, a printed circuit board with embedding active/passive components, is greatly paid attention as next generation high-density packaging technology to realize ultra-miniaturization of electronics package by increasing component mounting density.
Fujikura has established an embedded die technology called WABE Technology (R) (Wafer and Board Level Embedded Technology).
This technology consists of Cu redistribution layer on IC wafers (Fan-in RDL) and multilayer polyimide wiring board (FPC) and is under mass production for ultra-small medical devices.
We have expanded this technology and developed "Chip-stack WABE package" for the first time in the world, which is embedded die substrate with stacking multiple ICs in vertically into multilayer FPC.
We started mass production of two chip-stack type WABE package from 2018 and are also ready for three chip-stack type WABE package.
This technology received the 2018 Technology Award from The Japan Institute of Electronics Packaging (JIEP). We will continue to contribute to society through the miniaturization of electronic circuits.

High-density electronics packaging
by using embedded die technology,
WABE Technology (R)
Three chips stack WABE package 2018 Technical Award of The Japan Institute of Electronics Packaging (JIEP)

For inquiries regarding research and development, please contact us from here.

Connector Technology

Our company has been developing, manufacturing, managing quality and selling original connectors for about 60 years.
In recent years, there has been strong demand for small and light mobile devices, including smartphones, and there is also a demand for "ultra-low height"
"micro miniature" and "High mating operability" connectors.
Our company is developing connectors that are compact, light-weight, and multifunctional to meet the needs of this market.
In order to meet future demands, we will continue to refine the following technologies and develop world-class ultra-compact connectors.

【Design technology】
・Structural analysis technology developed over many years to ensure contact reliability
・Flow analysis technology capable of filling resin even with thin wall

【Production technology】
・Press die manufacturing technology and press process technology
・Resin molding die manufacturing technology and thin-wall resin molding technology
・High-speed automatic inspection, assembly and packaging technology
・Gold saving plating technology for ultra-small contacts

World's smallest board-to-board connector with
0.3 mm pitch and 0.6 mm height (FB3A series)
Press die with 1/1000 mm part accuracy Molding die with 1/1000 mm part accuracy

0.35 mm pitch micro-machining, 1/1000 mm part accuracy (Molding die) Automatic machine for assembling,
inspecting and packing at high speed

For inquiries regarding research and development, please contact us from here.