Pan Pacific Symposium Conference Proceedings

Fabric-Based Fine Pitch Interconnect Technology Using Anisotropic Conductive Films(ACFs)

Author: Kyung W. Paik
Company: Korea Advanced Institute of Science and Technology (KAIST)
Date Published: 2/6/2017   Conference: Pan Pacific Symposium

Abstract: Due to the increasing demand for higher performance, greater flexibility, smaller size, and lighter weight in mobile electronic products, there have been growing needs of wearable electronic products in near future. Wearable watches, glasses, wrist bands, shoes, and clothes have been recently introduced in the market.

To realize wearable electronic products, there should be four core electronic hardware technologies - (1) flexible semiconductor, (2) flexible display, (3) flexible battery and (4) flexible packaging & interconnection technologies. In the flexible semiconductor devices, ICs are thinned down to nanometer thickness, and then transferred to a polymer film. However, much more development is still needed for the real applications of flexible semiconductors in near future. In contrast, flexible displays are already available by introducing OLED (organic LED) realized on polymer base films. And flexible batteries are also demonstrated by several companies by adapting solid electrolytes. In order to realize flexible wearable electronics, there flexible components have to be packaged and interconnected with flexibility using flexible packaging technologies. However, there has been very few development on flexible packaging & interconnection areas.

As a one of the promising flexible packaging and interconnection technologies using flexible substrates such as polymer films and fabrics, fabrics can provide great flexibility and durability. Therefore, fabric-based fine pitch interconnection using ACFs materials will provide the solution for realizing various flexible wearable electronic products.

In the electronic packaging technology for fabric-based wearable electronics, FOF(Flex On Fabric) technologies using FPCs substrates and various fabrics with fine pitch circuits using ACFs interconnection materials become very important, because ACF interconnection provides excellent electrical flexibility compared with conventional solder- or socket-based interconnection methods which have a limitation of bending and flexing.

In this paper, it will be presented that more than 300 um pitch metal patterns can be successfully formed on various fabrics by a pattern transfer method. And it was found out that the FOF interconnection with excellent electrical contact resistance, good adhesion strength, and reliability were obtained using optimized ACFs materials designed for fabrics interconnection applications. Finally the fine pitch metal circuit technology combined with the FOF technology can provide excellent technical solutions for realizing flexible wearable electronics.

Key Words: 

Conductive fabrics, Flex to Fabric bonding, ACFs, wearable electronics

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