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42 FLEX007 MAGAZINE I JANUARY 2019 More than 20,000 results populate on an Amazon search for wearable technology. There is no question that wearable electronic devices have created a new electronics mar - ket, especially those earmarked for medical and healthcare. Wearable devices demand 3D flexible wiring, so flexible circuits are an appropriate solution for these devices. Wearable electronics require different perfor - mances from their circuit makeup compared with traditional flexible circuits. Previously, we advised customers to design flexible cir- cuits according to the standard design guide to optimize performance and manufacturing yields. Wearable electronics changed our way of thinking relative to these new performance prerequisites. 3D wiring is one of the major features of typical flexible circuits because of the flexibil- ity from the base materials. However, you are limited to the number of material choices for traditional flexible circuits. Designers create circuits with only a small selection of materials available. Polyimide film is one of the limited choices for high-temperature processes such as soldering and wire bonding. It has a good bal- ance as the dielectric material for traditional flexible circuits; however, it is not comfortable to wear polyimide films when used in clothing. Comfort is everything in wearable technology, but the low moisture permeability from plastic films does not provide this comfort when the films are attached directly to the skin. Film color is also a deterrent where artistic value is com- promised from the eyes of the consumer. The base materials require higher dimensional stabilities to increase process yields in high-density circuits, but healthcare devices need elasticity when attached to the body. Thus, a conflict exists with base materials. Exotic materials have been developed to satisfy these new requirements for traditional flexible cir- cuit technologies. The materials are not necessar- ily new products but rather modified to generate some unique performances. A few examples are listed here. EPTE Newsletter by Dominique K. Numakura, DKN RESEARCH Exotic Materials: A Prerequisite for Next-generation Flexible Circuits