Industrialization of Micro-Electro-Mechanical Systems. Werner Weber Infineon Technologies

Transcription

1 Industrialization of Micro-Electro-Mechanical Systems Werner Weber Infineon Technologies

2 Semiconductor-based MEMS market MEMS Market 2004 (total 22.7 BUS$) Others mostly Digital Light Projection IR Sensors RF MEMS Magnetic Sensors Optical MEMS Pressure Sensors R/W heads Inertia Sensors mostly inkjet printer heads µ-fluidic Opto Devices Image Sensors Page 2

3 Growth potential of different technologies Expected Growth Between 2004 and ,8 1,8 6,6 1,6 6,4 1,4 1,2 1 0,8 0,6 0,4 0 0,2 Page 3 RF MEMS Image Sensors Opto Devices µ-fluidic Inertia Sensors Pressure Sensors Optical MEMS IR Sensors Magnetic Sensors

4 Trends in MEMS Killer applications: the markets of Read/Write heads, Opto Devices and Digital Light Projection and Image Sensors for cameras and mobile phones have already taken off Emerging areas: acceleration sensors, pressure sensors, RF MEMS, biosensors for DNA analysis, water & air quality, body functions are future hype candidates Page 4

5 Other Trends The growing role of system integration Integration in system on chip Importance of packaging Separation of sensor and logic chip plus 3D integration More complex applications combine multiple sensor signals Application/customer-specific solutions (see next page) Page 5

6 Customer oriented solutions are a differentiator Sensor is a common part (traditional cantilever) BOSCH integrated such sensor in a regular bolt to fasten seat of car Customer just needs to replace existing bolts by new one functional housing of sensor - adapted to customer needs - finally yields differentiator Bolt weight sensor (BOSCH) Page 6

7 Agenda R/W Heads Image Sensors OptoDevices µ-fluidics Optical MEMS for Light Transmission Pressure Sensors Inertia Magnetic Sensors Infrared Sensors Radio Frequency MEMS Page 7

8 R/W heads (revenue of 9.3 BUS$ in 2007) Conventional R/W head R/W Gap Data field Advanced R/W head Pre-Erase Gap R/W Gap Data field Page 8

9 Image Sensors (revenue of 8.4 BUS$ in 2007) Page 9

10 5 Megapixel Image Sensor source: Micron/Nokia Page 10

11 Opto Devices for light generation (revenue of 3.8 BUS$ in 2007) Photodiodes Laser Pickup (of recorded data) Laser Transmitter Page 11

12 µ-fluidics (revenue of 2.3 BUS$ in 2007) InkJet Printing Biochip µ-pumps Nebulizer Needleless injector Drug delivery Micro reaction Lab-on-a-chip Page 12

13 DNA Detector Single stranded DNA Single Stranded DNA with marker Mismatch Match I I time Page 13

14 µ-fluidics (revenue of 2.3 BUS$ in 2007) InkJet Printing Biochip µ-pumps Nebulizer Needleless injector Drug delivery Micro reaction Lab-on-a-chip Page 14

15 Printer heads Target Ink Chamber Jet Nozzle Diaphragm Piezo device or Heater Page 15

16 Inkjet printer in action Simulation (increment of 25 µs) Photograph Source: Jyi-Tyan Yeh, Industrial Technology Research Institute, Hsinchu Taiwan 7th National Computational Fluid Dynamics Conference 2000 Source: M. Grove, et al., Display Works '99, Page 16

17 Recent trend: printhead integrated into printer. rather than into the print cartridge - reducing the cost for replacement ink cartridges source: Kodak/ST Page 17

18 Optical MEMS for light transmission (revenue of 2.0 BUS$ in 2007) Digital Light Projection/µ-displays Switches/ µ-mirrors Attenuators Filters µ-lenses Page 18

19 Principle of Digital Light Projection single pixel of digital micromirror device Projection system Page 19

20 Pressure Sensors (revenue of 1.6 BUS$ in 2007) Side airbag TPMS Page 20

21 Surface Micromachined Pressure Sensor integrated in 0.5µm BiCMOS Pressure n-mos p-mos 0.8µm Poly-Si-Membrane, capacitive sensing Typically two references and two sensors arranged in a bridge 10mbar overall accuracy Sensors for 0.1 to 3 bar, side airbag, motor management (intake pressure) Page 21

22 Pressure Sensors (revenue of 1.6 BUS$ in 2007) Side airbag TPMS Page 22

23 Bulk Micromachined Tire Pressure Monitoring System (TPMS) glass-silicon-glass stack Only silicon oxide exposed to media. All active parts are placed on the backside of the pressure membrane. Piezo resistors Vacuum Bond pads Vacuum Pressure Inlet Page 23

24 TPMS Device Analysis: X-Ray Page 24

25 Inertia (revenue of 1.4 BUS$ in 2007) Sensors Accelerometer Gyroscope Energy scavenging Microphone Page 25

26 Acceleration Sensor in TPMS glass-silicon-glass stack Only silicon oxide exposed to media. Acceleration sensor Bond pads Vacuum Page 26

27 Inertia (revenue of 1.4 BUS$ in 2007) Sensors Accelerometer Gyroscope Energy scavenging Microphone Page 27

28 Microphone Flexible Membrane Sound Stiff perforated backplate Spring supported membrane Membrane with corrugations Page 28

29 Magnetic Sensors (revenue of 1.1 BUS$ in 2007) Hall sensor Giant Magnetic Resistance sensor Page 29

30 Basics of Magnetic Sensing: Hall Effect B U V- U H U H+ U H I B U H- U V+ b d l U v : Supply Voltage for Hall Probe U H : Hall Voltage Page 30

31 Hall Probe 5 di siclk a_testn a_testp ext_scanmode_in Hall plates for 4 directions in the plain to compensate for noise iddq_sup 6 do 7 VDD 5 GND PGND cs 7 H 1 H 2 Distance of Hall plates equals distance of north and south pole of magnet: 2.5mm (differential principle) Page 31

32 Measurement Principle of Hall Sensor Differential Hall principle Programmable Gain Amplifier (PGA) to adjust signal level to Analog Digital Converter (ADC) Analog offset compensation Page 32

33 Giant Magnetic Resistance (GMR) principle spin dependent scattering of conducting electrons sensitive to in-plane magnetic field components anti-parallel alignment alignment ferromagnetic layer non-magnetic layer ferromagnetic layer Page 33

34 GMR spin valve system for angle sensing reference layer (RL) with fixed magnetization direction free layer (FL) with ability to follow ideally an external in-plane magnetic field Varying angle between FL and RL magnetization leads to a continuous change in stack resistance magnet NAF Page 34

35 GMR spin valve system for angle sensing 360 uniqueness by combination of orthogonal RL magnetizations NAF resistance (a.u.) (a.u.) angle Θ ( ) angle Θ ( ) arctan NAF measured angle ( ) angle Θ ( ) Page 35

36 360 Angular Sensor SIN COS Page 36

37 Advantages of GMR compared to Hall Higher sensitivity bigger airgap lower jitter GMR Hall B GMR sensitive only to inplane field bigger airgap independent to back bias field N S N S Hall GMR Page 37

38 InfraRed Sensors (revenue of 0.8 BUS$ in 2007) IR-temperature IR camera arrays Page 38

39 Bolometer Array for Night Vision Systems Thin-Film Thermistor Free Space Bolometer Vias Wafer Page 39

40 Infrared Night Vision System Page 40

41 RF MEMS (revenue of 0.7 BUS$ in 2007) Inductors Capacitors Bulk Acoustic Wave (BAW) resonators Switches µ-mech. resonators Page 41

42 Bulk Acoustic Wave Device Trapped acoustic wave 200µm Top electrode Piezo AlN Bottom electrode ~1µm acoustic mirror W SiO 2 Si substrate Aluminum Nitride (AlN) used as piezoelectric material acoustic mirror realized by buried W layers Page 42

43 RF MEMS (revenue of 0.7 BUS$ in 2007) Inductors Capacitors Bulk Acoustic Wave (BAW) resonators Switches µ-mech. resonators Page 43

44 Micro-Mechanical Resonators Source Discera Page 44

45 Conclusion MEMS have developed into a very dynamic field with exiting technical challenges and above-average growth rates Some applications have already developed into mature applications Read/Write heads, Digital Light Projection, OptoDevices and Image sensors for cameras and mobile phones others are yet developing Acceleration sensors, Pressure sensors, RF MEMS, Biosensors Page 45