E!10673 STEP-HIGH,SENSORS FOR MEDIUM TO HIGH PRESSURE RANGES FOR HIGH-VALUE MARKETS

Memscap has in the project developed a new pressure sensor family for high pressure measurements, 10 to 70 Bar up to a TRL3 level. These pressure sensors have been developed with regard to the requirements demanded by the aircraft industry for engine control on Jet- engines, the Full Authority Digital Engine Control (FADEC). To meet the future with ever more stringent requirements for pollution from jet engines and security requirements, it has been necessary to use new technology to a greater extent than what Memscap possesses today can achieve. MEMSCAP technology and manufacturing processes enable the company to deliver world-class products in reliability and stability, which is essential for being a supplier to the aviation industry. When the company has moved towards the motor control market where it is necessary to supply pressure sensors up to 70 Bar, it is primarily the existing technology that the company possesses that has been further developed. In the STEP-HIGH project, a focus has been placed on producing sensors that can withstand far greater environmental impact than the current technology could handle. Memscap has thus focused on four work packages in the project. All pressure areas, 10, 30 and 70 Bar sensor chips have been processed on SIO-silicon wafers. Test samples of 10, 30 and 70 Bar of sensor chips are made available and initial test results are very positive. It is also decided to run a second run on sensor wafers with buried conductors. This will be done in the following activities after the project ending. This is to be able to anodic bond reference chips at the wafer level stage for thus achieving a far more efficient assembly process. A new glass film for anodic bonding / laminating of silicon wafer has been developed in work package WP2 in cooperation with Memscap Inc. in the United States and a German company who has very good competence with anodic bonding processes. Memscap has previously achieved silicon wafers from the subcontractor for the glass-film process and has in the recent past made a series of pleasant tests of sensor wafers against the support wafers. Preliminary results are positive, but there must still be some more runs before the final process can be approved and documented. The project has also brought out a new silicon support chip that supports the sensor chip. With the help of FEM- simulations, a mechanical design has been developed to reach a structure that will completely isolate the stresses that occur on the bottom side of the support chip against the sensor element itself. Memscap has currently a complete design and process developed by Memscap Inc. in the United States. The project has received finished processed chips for assembly. Here, the challenges have been greater than previously assumed due to deep-RIE etching (abnormal deep-grows etched into the silicon wafer surface). Throughout the project period, there has been a great focus on establishing a good process for deep-RIE etching. This has the project successfully achieved and new wafers with deep-etched grows profiles are developed and processed. Furthermore, these support chips have been anodic bonded onto sensor wafers which are currently assembled as pressure sensor stacks in sensor housing. Test results have proven to be very satisfying. In work package WP3, a reference chip laminating process has been developed. This process has been developed with great success and has thus been transferred to the company's standard manufacturing process for existing products. Work package W3 is seen as successfully done. In the project it has also been necessary to develop a good and solid process for the soldering of the chip structure of the sensor stack. Great emphasis has been placed on achieving a proper solder alloy. In the project, silicon wafers with printed different types of metal alloys have been tested in various strength tests. Some preliminary force-tests have been made in cooperation with SINTEF and their NBRIX project. The tests have so far shown good results, but there remains some work before the final solution can be presented as a manufacturing process. Memscap will continue this work even after the project's end. In the work package WP5, an electronics solution for compensating the sensor signal has been developed with regard to operating characteristics in the temperature range -55 to 125 degrees C. Here are the selected components from Analog Devices in the United States. This company has been very helpful in the project and actually qualified their ADC component to satisfy the requirements that the aircraft industry requires. The circuit boards are currently available and are part of the prototypes that will be in the near future be presented to prospective customers. Memscap has good contact with leading motor control manufacturers. The company has already made arrangements with two U.S. producers who will assist with the qualification of the results. Initial discus

Memscap er svært fornøyd med resultatene som er fremkommet i prosjektet. - WP1 Resultater viser at trykk sensor brikker, 10, 30 og 70 bar gir gode resultater med sirkulært membran og har derfor gått videre med et nytt prosjekt for å videre utvikle sensorbrikkene med å introdusere begravde ledere for ytterligere forbedre stabilitet og produksjons effektivitet. - W2. I denne arbeidspakke har det blitt utviklet et nytt design på sensorens underlagsbrikke. Resultatene har her vært så gode at dette designet har også blitt introdusert på alle nye versjoner av Memscap sine eksisterende produkter. W3. Resultatene fra denne arbeidspakken har også vært vellykket. Resultatene fra tynn-glasfritt laminering har vært så vellykket at også denne prosessen har blitt introdusert på samtlige sensor produkter. WP5 Her har prosjektet tatt fram en helt ny elektronikk løsning for sensor kalibrering og kompensering. Denne løsningen ser ut til å være så god at muligens nye uforutsette markeder kan åpnes.

In the STEP-HIGH project, Memscap shall develop a new technology platform for piezo-resistive pressure sensors for pressure measurements ranges from 10 to 100 bar. The product family that shall be built based on this platform is targeting the high-value avionics applications "Full Authority Digital Engine Control" (FADEC)and "Auxilary Power Units" (APU). The product innovation will include development of a completely new transducer family with a small triple-stack chip solution with high burst pressure, low thermal hysteresis and long term-drift. A new chip assembly method between sensor chip and support chip shall be developed by using film anodic bonding and includes a smart support chip that make possible soldering of the chip stack into a package. The production innovation includes manufacturing of all versions of sensors on the same 150 mm diameter silicon-on-insulator (SOI) wafer, wafer-level-packaging instead of chip level assembly and the use of automatic die attach, handling, test and calibration of sensors and integrated transducer modules. The many research issues in the project are related to finding new "state-of-the" technical solutions to compete well in the demanding avionic market on performance, reliability, and price. A new ASIC design shall be developed in order to obtain the very best performance of the new sensor family. Project partners are Memscap and University of Montpillier LIRMM,