Embedded Flexible Hybrid Electronics for the Internet of Things

Abstract

The Internet of Things (IoT) “things” are often times described as active or smart devices and objects augmented with sensing, processing, and network capabilities. These smart objects are in the heart of the IoT concept but they alone cannot realize the full potential of IoT. The most ubiquitous objects in the IoT ecosystem, those that reside at the lowest system level and interact with the higher-level smart object, are based on the passive RFID technology. In the form of wireless passive sensors these objects are found in smart packaging, they form the backbone of the structural health monitoring systems, they provide non-invasive and continuous monitoring of physiological parameters, etc. RFID capability is already added to everyday items in the physical form of adhesive “smart” labels, enabling them to become “citizens” of the IoT ecosystem, but this “add-on“ approach increases the implementation cost and oftentimes impacts negatively the host item's form factor and appearance. It also does very little in terms of security and counterfeit prevention. On the other hand, the key economic factor that drives the deployment of the IoT is the cost at the end points. Therefore, the future of the IoT depends on developing an ultra-low-cost technology solution that can mass-produce low cost, RFID-enabled IoT objects on flexible substrates, ready for integration into everyday items. In some cases, such as in intelligent packaging, these objects will be non-obstructive and seamlessly integrated in their hosts. This integration will minimize the cost of implementation and will provide an insurmountable barrier to counterfeiters as they will need access to sophisticated and capital-intensive technologies in order to be able to alter or replicate the product's embedded configuration. Presented are two disruptive processes for packaging of ultrathin flexible hybrid electronic systems with ICs as thin as 15–20 μm and as small as 250 μm per side. The first generation technology is a modification of the conventional pick-and-place technique and has been already demonstrated on a commercial-grade roll-to-roll assembly line with packaging rates exceeding 10,000 cph. The second generation technology uses a laser beam to scan and transfer ultrathin, ultra-small ICs for high-precision assembly onto various flexible and rigid substrates. It provides packaging rates significantly exceeding those of the conventional pick-and-place equipment. Reported are also results from integrating the resulting ultrathin flexible hybrid electronic devices into thin materials such as paper and plastics.