MEMS Devices – Design, Packaging and Production Slide 1 MEMS Devices – Examples of Design, Packaging and Production Per Ohlckers SINTEF Microsystems and University of Oslo Picture shows a silicon microphone in development by the start-up company 54.7

MEMS Devices – Design, Packaging and Production Slide 2 Outline of talk Mainly a presentation of Norwegian MEMS activities Main challenges of the Microsystem/MEMS industry Examples of MEMS devices Future and Conclusions: A strong market pull will stimulate the needed maturing of the Microsystem/MEMS industry and its technologies Picture shows details of the SP13 tyre pressure sensor from SensoNor

MEMS Devices – Design, Packaging and Production Slide 3 Applications for MEMS/Microsystems: The biomedical market – Blood pressure sensors The space, defence and avionics markets – Accelerometers for rocket navigation – Micro gravity sensor – Gyroscopes for navigation The agriculture electronics market – Automotive sensors used in tractors, harvesters etc. The off-shore oil exploitation market – High pressure measurement in oil wells – Sea wave sensor The automotive market – Acceleration microsystems for air bag systems – Tire pressure microsystems The data and peripheral market – Disk drive write and read heads The consumer market – Photo diodes in cameras – Level measurement in white goods appliances.

MEMS Devices – Design, Packaging and Production Slide 4 Market for Microsystems/MEMS Devices Ref.: Nexus Market report

MEMS Devices – Design, Packaging and Production Slide 5 Norwegian Microsystems/MEMS activities Main players: –SensoNor –SINTEF Microsystems –Startups NORCHIP Presens Photonyx Lifecare 54.7 –Universities NTNUI, Trondheim University of Oslo New initiative: NMC, Norwegian Microtechnology Centre –Picture shows the future Microtechnology Research Laboratory in Oslo, construction started this autumn

MEMS Devices – Design, Packaging and Production Slide 6 Example: SP80 Pressure Sensor Vintage from the early eigthies – but still in production Developed at SINTEF (earlier Center for Industrial Research), Norway and manufactured by Capto, subsidiary of SensoNor (earlier ame), Horten, Norway. This sensor visualises the main features and limitations of micromechanical sensors, and points out pressure sensing as a main application for these kinds of sensors.

MEMS Devices – Design, Packaging and Production Slide 7 The SP80 Silicon Chip Set - Drawing Consists of diaphragm chip sealed to a support chip which is mounted on top of a glass tubing acting as a mounting stand as well as a pressure port

MEMS Devices – Design, Packaging and Production Slide 8 The SP80 Silicon Chip Set - Picture Consists of diaphragm chip sealed to a support chip which is mounted on top of a glass tubing acting as a mounting stand as well as a pressure port

MEMS Devices – Design, Packaging and Production Slide 9 SP80 Package, continued Cross-sectioned view of the SP80 Pressure Sensor packaged in a transistor header with a top chip containing a vacuum reference chamber

MEMS Devices – Design, Packaging and Production Slide 10 SP80 Schematic The SP80 schematic consists of 4 ion implanted piezoresistors in a full Wheatstone bridge configuration as the electronic sensing element. In addition, a temperature measuring resistor and a heating resistor are implanted on the same chip, to compensate or thermostat the chip to minimise thermal drifts

MEMS Devices – Design, Packaging and Production Slide 11 Picture of SP80 in Transistor Package Comment: The Norwegian coin is approximately the size of Ø10 mm

MEMS Devices – Design, Packaging and Production Slide 12 Top10 Success Factors 1. Batch organised processing technology1. Batch organised processing technology 2. Microelectronics manufacturing infrastructure2. Microelectronics manufacturing infrastructure 3.Research results from solid state technology and other related fields of microelectronics3.Research results from solid state technology and other related fields of microelectronics 4.Micromachining4.Micromachining 5. Wafer and chip bonding5. Wafer and chip bonding 6. Mechanical material characteristics6. Mechanical material characteristics 7.Sensor effects7.Sensor effects 8.Actuator functions8.Actuator functions 9.Integrated electronics9.Integrated electronics 10.Combination of features10.Combination of features

MEMS Devices – Design, Packaging and Production Slide 13 Bottom10 Limiting Factors 1.Slow market acceptance1.Slow market acceptance 2. Low production volumes2. Low production volumes 3.Immature industrial infrastructure3.Immature industrial infrastructure 4. Poor reliability4. Poor reliability 5. Complex designs and processes5. Complex designs and processes 6. Immature processing technology6. Immature processing technology 7. Immature packaging and interconnection technologies7. Immature packaging and interconnection technologies 8. Limited research resources8. Limited research resources 9. Limited human resources9. Limited human resources 10. High costs10. High costs

MEMS Devices – Design, Packaging and Production Slide 14 Manufacturers of Microsystem/MEMS Devices The industry structure is highly diversified both in size, technological basis and organisation type. –Traditional sensor manufacturers have seen micromechanical sensors as a natural expansion of their technological basis, and have taken up research and production of these sensors as a part of their activity. –Semiconductor companies have entered this market as an expansion of their integrated circuit activity, since they already have most of the needed equipment and the appropriate marketing channels. –System companies or original equipment manufacturers which see micromechanical devices as a way to boost their systems. –"Start ups", companies having micromechanical devices as their main business idea. There are of course companies that does not fit into any of these types and some are someplace in between these types.

MEMS Devices – Design, Packaging and Production Slide 15 Example: The 54.7 Photoacoustic Gas Sensing Silicon Microsystem

MEMS Devices – Design, Packaging and Production Slide 16 Motivation: Microsystem technology can give cost effective photoacoustic gas sensors with high performance – Batch organised manufacture for low cost –Silicon micromachining for high performance and small size –Piezoresistive microphone for high-sensitivity sensing of the photoacoustic signal –Multistack wafer anodic bonding to produce the hermetic target gas chambers –etc The start-up microsystem company 54.7 started its operation on September 1, 1999, with its first venture to commercialise this patented scheme for photoacoustic gas sensing modules using microsystem technology

MEMS Devices – Design, Packaging and Production Slide 17 Technology of 54.7 The 54.7 Photoacoustic Gas Sensing Technology – Using a silicon micromachined acoustic pressure sensor with an enclosed cavity with the gas species to be measured as a selective filter. This intellectual property is protected with 3 patents.

MEMS Devices – Design, Packaging and Production Slide 18 Technology of 54.7, continued Absorbed modulated IR radiation is converted into acoustic signal in a sealed gas chamber The photoacoustic principle Window Microphone ~ Pressure sensor Gas Modulated IR source

MEMS Devices – Design, Packaging and Production Slide 19 Conventional Photoacoustic Gas Sensor Well known with high performance at high cost IR-filter Microphone IR-window Mirror Microphone Display Lock-in amplifier Oscillator Power supply Pulsed IR source Valve Pump

MEMS Devices – Design, Packaging and Production Slide 20 Photoacoustic Technology of 54.7 Increased amount of target gas present in the absorption path gives a correspondingly decreasing photoacoustic response in the sealed target gas chamber due to the transmission loss Explain better! Include absorption lines etc!!!

MEMS Devices – Design, Packaging and Production Slide 21 Photoacoustic Response Decreasing PA signal with increasing gas concentration in absorption path. Here shown at 8 HZ modulation Output voltage from amplifier [mV] time [ms] PA-signal Emitter voltage Emitter radiation Response without gas in absorption path

MEMS Devices – Design, Packaging and Production Slide 22 The Diamond-like Thin Film/Silicon Micromachined IR Emitter Manufactured by Patinor Coatings –Based upon Diamond-Like Carbon (DLC) thin film heating resistor on silicon micromachined diaphragm structure: 1: Bonding pads 2&3: SiO2 4: Si3N4 5: DLC film –Using a CVD process to deposit the DLC thin film –Pulse modulated high speed broad band grey body IR emission –Working temperaure about  C –High reliability

MEMS Devices – Design, Packaging and Production Slide 23 CVD Process for the IR Emitter Silicon-organic liquid (C 2 H 5 ) 3 SiO[CH 3 C 6 H 5 SiO] 3 Si(CH 3 ) 3 (PPMS) is used as a plasma-forming substance of the open plasmatron Doping by molybdenum is done during plasma deposition process wafer by magnetron sputtering of a MoSi 2 target in argon atmosphere Pressure is about 5  Pa, the magnetron current is about 2 A, the plasmatron arc discharge current is about 6 A By changing those deposition parameters it is possible to modify the resistance of the IR emitters

MEMS Devices – Design, Packaging and Production Slide 24 Principle of a Microsystem based Photoacoustic Gas Sensing Cell (Early Prototype) The photoacoustic sensing microsystem is enabled by packaging a silicon micromachined acoustic pressure sensor chip in a transistor package 10.0 mm TO-header IR radiation 4.0 mm Silicon micromachined acoustic pressure sensor chip Target gas Window Absorption chamber Transistor cap

MEMS Devices – Design, Packaging and Production Slide 25 Silicon Microphone Prototype Designed by SINTEF and 54.7 Piezoresistive with centre boss structure Manufactured by SensoNor with their Europractice/NORMIC multiproject wafer foundry services

MEMS Devices – Design, Packaging and Production Slide 26 Silicon Microphone Prototype: Design and Process Piezoresistive with centre boss structure –Chip size is 6 mm x 6 mm. Diaphragm diameter is 2 mm SensoNor/NORMIC process: Process E/ MPW : Combined Diaphragm- and Mass-Spring-based Piezoresistive Sensor Process –3 micrometer epitaxial layer –2-level etch stop using anisotropic TMAH process with electrochemical etch stop at 3 and 23 micrometers –Buried piezoresistors with 480 Ohm/square sheet resistance –Anodic bonded triple stack glass-silicon-glass structure

MEMS Devices – Design, Packaging and Production Slide 27 The 54.7 photoacoustic gas sensing cell design Cell with silicon or electret microphone –Electret microphones model 9723 from Microtronic used in present prototypes IR-emitter Microphone Perforated aluminum tube IR window or filter Thermopile or pyroelectric IR reference sensor 90 mm Target gas 6mm IR radiation Absorption path

MEMS Devices – Design, Packaging and Production Slide 28 Sensor Module Design Sensor module with the gas sensing cell mounted on a surface mount printed circuit board with analog and digital electronics for monitoring, control and interface Size approximately 70mm x 20mm x 10mm

MEMS Devices – Design, Packaging and Production Slide 29 Preliminary Test of Silicon Microphone versus Electret Microphone Comparable signal-to-noise performance

MEMS Devices – Design, Packaging and Production Slide 30 Test of the DLC IR Emitters Power efficiency about 0.1

MEMS Devices – Design, Packaging and Production Slide 31 IR Emitters: Radiation Spectrum Useful IR spectrum from around 1 to around 10 micrometers

MEMS Devices – Design, Packaging and Production Slide 32 Main characteristics of the IR Emitters Resistance value: Nominal 55, from 35 to 125 Ohms Supply voltage: From 5 up to 12 V Power consumption: 0.5 – 1.0 W Maximum frequency modulation of the emitted energy: 200 Hz (~100% modulation at 10 Hz) Working temperature of film resistor: o C, with header temperature not exceeding 70 o C Warm-up time: < 30 s The emissivity factor of the emitting surface: ~0.8 Emitting efficiency ( =3-14 micrometers): ~10% Life time: Mean Time Between Failure (MTBF) of more than hours (more than 3 years)

MEMS Devices – Design, Packaging and Production Slide 33 Preliminary experimental results of CO2 module prototype Graph of 15 hours measurement (one sample per minute) Lab test: Increased CO2 at start and at inspection. Resolution around 0.3 ppm. Accuracy around ±10ppm? Temp Vref Vref-temp-c Vg Vg-temp-c Vg-temp-ref-c approximately: 25 ppm CO2 1 o C

MEMS Devices – Design, Packaging and Production Slide 34 Status of this gas sensor development The concept is promising for commercialisation Low cost, high selectivity, and high sensitivity can be achieved –Example: CO2 measured with around 10 ppm accuracy and 0.3 ppm resolution Potential show stoppers Long term drift and thermal effects –Example: Some thermal effects are yet to be understood and minimised Further work Long term stability need to be verified further Thermal effects will need to be investigated, reduced and compensated Low cost microsystem production technology need to be further developed

MEMS Devices – Design, Packaging and Production Slide 35 Example: Digital Micromirror Device (DMD) from Texas Instruments The device is using very advanced surface micromachining of thin Al alloys on Si substrates containing CMOS drive electronics

MEMS Devices – Design, Packaging and Production Slide 36 Picture of the packaged DMDs The DMDs are pixel devices Here are the VGA (640x480), the SVGA (800x600) and the XGA (1024x768) devices shown

MEMS Devices – Design, Packaging and Production Slide 37 Principle of Operation for the DMD The hinge system of each pixel structure enables electronic control mirror position.

MEMS Devices – Design, Packaging and Production Slide 38 Picture of Digital Micromirror Device The device is packaged in an elastomer connect package with a glass window. Here shown mounted on a PCB with back end drive electronics

MEMS Devices – Design, Packaging and Production Slide 39 The Davis DPX 16 Projector using the TI Digital Micromirror Device XGA resolution (1024 x 768 pixels) 2.3 kg weight 1000 Lumens brightness

MEMS Devices – Design, Packaging and Production Slide 40 Example: The SP13 Tyre Pressure Sensor from SensoNor Fully integrated temperature and pressure sensor Internal State Machine Patented sensor design Pressure sensor: Range: 50 – kPa Resolution: 2.5 kPa Accuracy: +/- 10 kPa

MEMS Devices – Design, Packaging and Production Slide 41 Example: Microgyro from SensoNor Challenging signal-to-noise ratio High vacuum sealing to obtain high Q factor

MEMS Devices – Design, Packaging and Production Slide 42 PreSens: High Pressure Sensors Sensor concept Silicon piezoresistive sensor element High output signal High overload capability Dynamic range > 130 dB Pressure sensing Full scale range bar to bar Pressure accuracy  0.05 %FS Temperature range Standard T:-40 °C to 130 °C High T:-40 °C to 200 °C Temperature sensing by R bridge (T) Temperature accuracy  0.3 °C Signal conditioning circuitry Customized steel housing With or without diaphragm to isolate from aggressive media Small dimensions (from 2 cm 3 )

MEMS Devices – Design, Packaging and Production Slide 43 Main application: Imaging systems like projectors Optical modulators Photonyx

MEMS Devices – Design, Packaging and Production Slide 44 NORCHIP microTAS (Total Analysis System) for biotech applications

MEMS Devices – Design, Packaging and Production Slide 45 Future and Conclusions: A strong market pull will stimulate the needed maturing of the Microsystem/MEMS industry and its technologies The Microsystems/MEMS industry is maturing into a separate industry A lot of innovations taking place these days – some examples have been presented The Norwegian Microsystem/MEMS activities are promising growing