According to forecasts there will be as many as 24 billion networked objects by 2020 – more than a third of these being »smart« everyday objects that communicate and interact as part of the Internet of Things (IoT). A key issue here is energy supply: the smart objects have to be energy self-sufficient in order to be able to operate for as long a period as possible. The EU project EnSO (Energy for Smart Objects) involves 39 partners from eight countries working on new solutions for an intelligent energy supply.
The aim is to develop so-called AMES (Autonomous Micro Energy Sources). AMES combine various elements such as energy harvesting, energy management and micro-energy storage devices in order to ideally enable a lifelong operating period.
In this project, Fraunhofer EMFT researchers are developing concepts and technologies to integrate and embed electronic microchips in autonomous energy supply units. These compact packages will be well under one millimeter in height, and the aim is also to make them mechanically deformable so that they can be adapted to different environmental shapes. For this purpose, the Munich experts are seeking to embed a very thin, bendable microchip in an ultra flat foil casing. Various technology concepts are currently being tested for the contacting: good results have been achieved with flip-chip contacting where the chip is set face-down on a wiring foil, contacted and embedded. The new packages proved to be robust in the first reliability tests. At the same time, a new concept has been developed in which the chip is set face-up on a foil and embedded with a casting compound. In an initial sample, the electrical contacting and the creation of the wiring level was achieved by means of laser opening of the vias, stencil printing of contacts and fan-out wiring. In the next version, the connections will be realized using established thin-film lithography methods. This will then make it possible to create packages for chips with complex pad geometries.