Optimizing mSAP to Produce Flex for Biofluid Sensor Probes

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Improvements in flexible printed circuitry technology offer solutions that enable advancement in other technologies, enabling new circuit design and capability possibilities for customers’ applications. This article will overview advancements developed and implemented to produce a flexible circuit that meets new and challenging requirements for a customer’s medical application. This discussion will highlight development ideas more than details about the final processing scheme.

The medical application was a sensor designed to be inserted in a body to monitor activity of fluids by measuring minute electrical inflections.  Good circuit performance required circuit production that achieves specific geometric precision of small circuit features with net ends far apart. Feature dimensions of the circuit design were approximately 75 µmdistance in one of the axes combined with overall length of approximately half a meter between net ends on opposite layers for circuit components and connector terminations.

An additional requirement was that the base material needed to be very thin to physically fit within the medical device. The material choice was Novaclad diclad, which is adhesiveless and available with 25 µm polyimide film, a very thin and flexible construction—appealing to the customer for functioning well in their application. The processing technique needed to be modified semi-additive processing (mSAP).

To read this entire article, which appeared in the October 2024 issue of Design007 Magazine, click here.