A swallowable diagnostic capsule with a direct access sensor using Anisotropic Conductive Adhesive

Technological developments in biomedical microsystems are opening up new opportunities to improve healthcare procedures. Swallowable diagnostic sensing capsules are an example of this. In this paper, a novel direct access sensor (DAS) has been demonstrated which uses Flip Chip (FC) technology to expose the sensor to the liquid medium. An electrochemical study showed that the Anisotropic Conductive Adhesive (ACA) joint provides good connection and does not impair the sensor functionality. The reliability test results showed that most of the samples survived the humidity aging test and that only 2 out of 9 ACA connections of the same electrode failed. For the failed samples, the failure analysis showed that the tensile stress at the chip/epoxy interface caused a delamination at this interface.