Sensor Layer of a Multiparameter Single-Point Integrated System

Microfabrication and circuit integration provide sensors with reduced size, improved performance, increased reliability, and lower cost. These microsensors can measure a variety of properties and behaviors, and are typically constructed on a range of substrate materials in combination with signal conditioning, information processing, and data-communication electronics. The challenge remains to integrate multiple sensors, each measuring different parameters with separate supporting electronics, into a single. high-density microsystem. We describe a multiple parameter medical sensor that is suitable for mounting on an active moving patient where mechanical flexibility, tight adhesion, lightweight, small size, and biocompatibility of an easily applied flat stick-on assembly at a single skin site are important considerations. Traditional microintegration technologies, such as system-in-package and system-on-chip, typically create lumped aggregations of components. In this paper, the flat architectural platform of a multiparameter sensor system is presented with microcircuitry distributed across multiple stacked layers that can be easily bent to fit body contours. The silicone-encapsulated fabrication of a thin foldable polyimide substrate with distributed surface-mount electronics is demonstrated. The measured performance results are discussed with a particular focus on the assessment of vibration-sensing elements after integration into this type of system has been described.