Motion sensors for hostile environmental applications or reliability under Harsh Environment MNT Reliability Workshop May 2008 Colibrys, Jean-Mi Stauffer
Colibrys in short Colibrys is a world-leading supplier of standard and customized MEMS based motion sensors for Harsh environment and Safety Critical Applications. Colibrys has the full breadth of MEMS capability, undertaking: sensor and systems design sensor manufacture packaging and test of MEMS components and subsystems. Colibrys is focusing its business growth in the Energy, Military, Aerospace, Industrial and Instrumentation markets. 2
Harsh environment Definition Any condition of extremes relative to the human condition (temperature, humidity, atmosphere (corrosin, pressure...), radiation, shock) Simple test: 3 If this device were a human being and subject to the conditions of its environment -- the highest and lowest temperatures, the amount of pressure, or amount of shock, would it be expected to survive?"
Applications A large number of applications conform to this Harsh Environment definition PRESSURE PARTICLE DETECTION VIBRATION SENSOR FLOW SENSOR HARSH ENVIRONMENT GAS SENSOR RF SENSOR ACCELEROMETER BOLOMETER X-RAY DETECTION SEISMIC SENSOR SHOCK SENSOR GEOPHONE GYROSCOPE 4
Applications A large number of sensors are required for these applications PRESSURE PARTICLE DETECTION VIBRATION SENSOR FLOW SENSOR HARSH ENVIRONMENT GAS SENSOR RF SENSOR ACCELEROMETER BOLOMETER X-RAY DETECTION SEISMIC SENSOR SHOCK SENSOR GEOPHONE GYROSCOPE 5
Applications Some of them are part of the Motion sensor market this is Colibrys business PRESSURE PARTICLE DETECTION VIBRATION SENSOR FLOW SENSOR HARSH ENVIRONMENT GAS SENSOR RF SENSOR ACCELEROMETER BOLOMETER X-RAY DETECTION SEISMIC SENSOR SHOCK SENSOR GEOPHONE GYROSCOPE 6
Main fields of applications for motion sensors Automotive Aerospace Military Industry Energy Accelerometers Inertial sensing Seismic sensing Vibration sensing Tilt sensing Gyroscopes 7
Harsh environment conditions Typical extreme conditions: Pressure Vibration Acceleration Shock Temperature Radiation Electromagnetic Corrosion Up to 5 000 mbar Up to 40 khz 0.2 g for seismic sensing 400 g for inertial sensing 2000 g for vibration sensing 100 000 g for fuzing 20 000 g to 40 000 g, 0.1ms to 10ms -120 C to 700 C or more mrads/ year 10 100 Tesla Chemical, abrasive Extreme conditions are different from one application to the other: i.e. 400g acceleration is large for inertia and remains low for vibration All specifications of a sensor must be insured under these extreme conditions: i.e. post-shock stability has to be considered on top of survivability Reliability must be ensured even under such conditions (safety critical applications) 8
Harsh environment market for motion sensors 100 Harsh Environment Hybrid approach (multi-physics material) Monolithic approach (MEMS above IC) Volume 9 Added Value Instrumentation & Industrial Medical Telecom 10 Automotive IT & Multimedia 1 Consumer Goods 10 K 100 K 1 M 10 M 100 M
Example of a hybrid MEMS accelerometer MEMS sensor Ceramic packaging Die attach / assembly Custom electronics 10
MEMS advantages for Harsh environment Inherent strong technology Robust materials (Si, SiC ) Reliable and precise manufacturing techniques (Safety critical) Scaling effect Small size assembly Mounting of sensors and electronic in less than 0.25cm 3 (< 0.015 inch 3 ) Low weight A MEMS motion sensor weight typically < 2grams (including packaging and electronic) Example: Shock resistance of a Silicon MEMS accelerometer vs a standard vibrating structure in quartz is: >20 times higher for a standard version (6000g compared to 300g) >100 times higher for a high shock version (>20 000g compared to 300g) 11
Technology platforms T sensor MEMS sensor Ceramic packaging Die attach / assembly Custom electronics Technology platforms required for harsh motion sensors: Design and manufacturing of a robust sensor Fabrication of a ruggedized electronic Reliable and strong assembly and packaging techniques Complex and advanced testing capabilities Application know how (Aerospace, military, Energy, Industrial ) 12
Robust sensor design and manufacturing Advanced design capabilities Sensor design and modeling Robust design of the spring-mass (i.e. management of resonant frequencies) Consolidation of the sensor box by design (i.e. minimizing constraints effects like T or shocks) Selection of the right material Silicon, SOI, SiC, Quartz, Diamond MEMS silicon wafer manufacturing Microelectronic like technology dry / wet etching, oxidation, metal deposition 13 Very precise and repetitive processes High temperature manufacturing steps (>1000 C) SFB (Silicon Fusion Bonding) minimizing constraints Batch manufacturing
ASIC / Electronic constraints Electronic is characterized by: Close to the ultimate point of use Chemically and corrosive or erosive environments At extreme temperatures -125 C to +700 C In high radiation fields Under high vibration levels Development and manufacturing of harsh environment electronics is a science in itself. Development area are: Electronic system design and modeling ASIC circuit design Manufacturing with various new materials Si, SOi, SiC Harsh environment electronics are not easily available (cost, complexity) Standard ASIC technology can be pushed to limits and still satisfy a wide range of applications 14
Assembly and packaging technologies Assembly and packaging are key to insure the conformance to tight specifications Assembly - Soldering or gluing reliability - Minimizing impact of external constraints - Filtering of some external effects (resonant frequencies, shocks ) Packaging - Material selection (Ceramic, plastic, metal ) - Soldering temperature management - Mastering of temperature expansion - Hermetically sealed multi chip modules (MCM) Event or post harsh event survivability is not sufficient and conformity to specifications is required. 15
Qualification and testing Standard testing equipments are generally not capable to reproduce extreme conditions Some harsh conditions can be obtained by combination of standard tests i.e. Hammer test + centrifuge to simulate a gun hard shock Combination of extreme conditions are sometimes quite impossible to reproduce i.e. gun hard shock of 25 000g at extreme temperatures Systematic testing are not necessarily possible (financially or technically) validation by qualification is required Exemple of high shock Aerobut testing (25 000g, 8ms, half sine) 105 mm Gun - L31 - Charge 5 - Internal Ballistics Linear Shot Acceleration vs. Time 20 Acceleration (gn) Thousands 15 10 5 0 0 2 4 6 8 10 12 Time (ms) 16
Harsh environment, already a reality! Standard Silicon based technology platforms are already in place to respond to a large number of market demands Current barriers are mainly linked to: Sensor and actuator material Electronics Assembly and packaging techniques Vibration 40g rms Shock Harsh environment with standard technology ~40 000g Temperature Environment Security 200 C Radiation, ESD, Chemical, Biological Reliability, Safety critical > 500 C 17
Harsh environment and motion sensors Two concrete examples of motions sensors for harsh environment provided by Colibrys Digital MEMS geophones for seismic imaging Highly sensitive detection of low frequency signals produced from natural (earthquakes) or induced movements (explosions) Very high shock MEMS accelerometers >20 000g, 8ms, half sine Valid between -45 C to + 80 C Minimum impact on specifications required 18
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