SALSA

The SALSA project aims at developing a micro-sensor enabling wireless process control in industrial applications operating at elevated temperatures (up to 1000°C) where no conventional wireless sensor can survive. The sensor consists in a surface acoustic wave (SAW) device based on AlN/Sapphire layered structure. A key issue of this development lies in the wireless and the battery-less requirement of such sensors and the good stability of the considered structure in high-temperature conditions. Since the consortium partners have already solved partially or even completely some of the problems related to the targeted environments, the real scientific advance therefore consists in the achievement of a high performances and relatively low cost micro-sensor capable to operate at high frequency and in high temperature conditions. As a backup solution but also as source of intellectual properties and high level journal production, original structures such as packageless WLAW (Waveguiding layer acoustic wave) and a new type of FBAR (film bulk acoustic resonator) will be also investigated. The SALSA partnership involves a large company (Arcelor-Mittal) as a end user, a high-tech start-up “frec|n|sys” exploiting technological equipments consisting in a whole industrial fabrication line allowing for the fabrication of SAW resonators, filters and sensors addressing almost any kind of RF application requiring such components, an SME “Senseor” as subcontractor, with a strong experience in the field of wireless SAW sensors, and four academic laboratories IJL, IMN, LMOPS and SYMME bringing their strong knowledge and experience in material field, an essential building block for the achievement of such project, but also in devices including SAW sensors. These laboratories also exhibit strong experience concerning the characterization of materials as well as sensors, at elevated temperatures. Scientific and technologic challenges of SALSA project concern: - The study and the optimization of the different materials composing the micro-sensor (piezoelectric film, metallic electrodes, substrate) and associated antenna, to meet requirements for an optimal behaviour at elevated temperatures. - The design of high performances SAW devices based on AlN/Sapphire substrates. - The development of a packaging solution allowing operation at temperatures in excess of 600°C for several hundred hours integrating antenna connection and assembly. - Customization of the transceiver for wireless interrogation to match the performances of sensors in high temperature environments. Thanks to the SALSA project the end-user partner “ArcelorMittal” is expecting an improvement of product quality (less scraps and new warranty), a time-to-market reduction and a cost reduction (through energy saving). This will give ArcelorMittal a great advantage in terms of product quality, price and services in comparison to its competitors. The use of SAW devices as passive and wireless sensors allows them to operate in extreme conditions such as those with high levels of radiation, high temperatures, or electromagnetic interference, in which no other sensors can operate. The results of the SALSA project can contribute in the future to the development of similar SAW devices able to operate in high temperature environments for applications in aerospace, power, nuclear, chemical, and petrochemical processes plants. For instance, the sensor developed for ArcelorMittal applications may be directly transportable not only to the glass industry, but also to control the temperature of high voltage cables to optimize the transport of energy, and in automotive applications for the control of combustion in engines. Hence, the SALSA project will give frec|n|sys and Senseor an innovative product and an opportunity to propose new measurement devices and to do a huge step forward in the measurement services they can offer.