Circuits Flex Their Muscles
Posted in Electronic Components by bmichaels on December 4, 2014The demand for more-capable devices in smaller packages has led to the increased use of flexible circuits in medical device applications.
Medical device design, development, and manufacturing are increasingly being influenced by two interrelated technology trends: the use of electronics and miniaturization. The more complex a device is, the more likely that it will incorporate complex electronic systems, and the smaller it becomes, the more likely that the electronics will shrink as well. But how are manufacturers meeting the challenge of squeezing ever-smaller electronics in ever-downsized medical devices? The answer is simple: flex circuits.
“The demand for more-capable devices in smaller packages has led to the increased use of flexible circuits in high-reliability medical device applications,” remarks John Daniel, business manager of the flexible printed circuit division at Plymouth, MA–based Tech-Etch Inc. “In order to support more-complex electronic assemblies and meet the demand for miniaturization, everything from the circuit traces to the surface-mount technology components attached to the circuit have decreased in size.”
Ballad of a Thin Circuit
Flexible circuits, such as those manufactured by Tech-Etch Inc., provide the thinnest and lightest means to create interconnects.
Flex Circuits are typically fabricated on a polyimide film substrate, Daniel comments. While, the traces are most often made of thin copper, other materials can be used for specific applications.
The circuitry is fabricated using either an additive or a subtractive process. In the subtractive process, the copper is already at the required thickness, and the trace geometry is patterned using an etching technique. In contrast, the additive process starts with extremely thin copper measuring from 2 to 4 µm, upon which additional copper is plated and etched to achieve the geometry required by the design. While both methods achieve the same end result, subtractive pro