Article published Microelectronics
Chips at the very heart of materials
Diabolo: a new technology for building electronics directly into textiles, plastics or composite materials at the manufacturing stage.
RFID tags and temperature, pressure or humidity detectors are used in a growing number of traceability, product tracking and home automation applications. “By directly integrating electronics into materials, our discovery makes it possible to connect chips - mere 500 µm cubes - directly to 100 µm electrical wires, similar to the threads used in the textile industry,” explains Dominique Vicard, one of the inventors of this patented technology, called Diabolo. With its minute packaging integrally mounted on a silicon wafer using conventional deposition and etching techniques, the chip is barely visible on its wire. The package obtained is easy to make and extremely tough and can be used in many industrial manufacturing processes, not only in textiles but also in plastics, composites, paper, concrete or tar. Unlike other solutions in which flexible, often highly sophisticated electronic components are mounted on top of the material, Diabolo is inserted into the material in a way that is compatible with the manufacturing requirements of each sector. This entails designing special package protection for each material and industrial process. For example, the chip can first be coated in plastic for extruder tests (in which softened plastic is pulled through an extrusion die to obtain long sectional shapes). Two textile applications have been devised. One is a light-emitting fabric (incorporating a light-emitting diode or LED), which could be used to make safety clothing for road maintenance and emergency response teams. The other fabric developed is equipped with a “stand-alone” RFID tag with a UHF antenna for use in all existing RFID applications. Researchers are also thinking up other applications, such as anti-theft devices concealed in the seams of clothing, simple packages containing a temperature sensor and RFID tag for home automation applications, or even more complex microsystems (MEMS) combining a sensor, RFID tag, processor and battery: “We can already make chip strings,” adds Dominique Vicard. “Specific circuits need to be designed in collaboration with interested partners. We are prepared to study any type of application and industrial material manufacturing process.” So far, spinning processes have been tested on weaving looms and tests have also been performed on industrial extruders, calendering machines (used to insert a material between two plastic films) and in concrete moulding processes. The team is working with industrial partners to design a machine for automatically inserting electronic devices on metal wire. The ultimate aim is to insert 10, 000 units per hour.
