MICRO ELECTRO MECHANICAL SYSTEMS ASSIGNMENT A CASE STUDY OF MEMS INDUSTRIAL PRODUCTS By M.Tech 2nd semester Applied Electronics & Instrumentation 2013-2015 MEMS (Micro Electro Mechanical Systems) is a technology that can be defined generally as miniaturised mechanical and electromechanical systems that are made using the techniques of micro fabrication. The physical dimension of MEMS devices can vary from well below one micron to several millimetres. The pioneer of MEMS industry was ‘hp’ (Hewlett Packard). After that so many industrial giants entered in to the world of MEMS device fabrication and became successful. The following list shows the leading manufacturers of MEMS devices and their turnover in the year 2012*. Company name Founded year ST Micro electronics Robert Bosch Texas Instruments Hewlett Packard Panasonic Knowles Electronics Denso Canon Avago Technologies Freescale semiconductors *courtesy of Yole development **spin off from Motorola 1957 1886 1951 1939 1918 1946 1949 1937 2005 2004** Turnover in the year 2012(Million USD) 1000 842 825 645 440 386 356 279 276 268 Growth rate (%) (year 2012) 10 14 - The most demanded MEMS components in the market are accelerometers The following list shows different MEMS components and their market share*** MEMS device IJ heads Pressure sensors Accelerometers Micro fluidics Gyroscopes Microdisplays RF MEMS Market share (2012) % 17.62 9.95 13.23 14.74 11.16 11.32 8.7 Si microphones 2.46 Microbolometers 2.69 MOEMS 2.79 *** courtesy Yole development Different MEMS components are introduced in the following pages. 1) MEMS INERTIAL SENSOR: • • • • • Company name Component Name Cost of product Dimensions Packaging : ST Microelectronics : LIS344ALH : (5-6 )US$ : 4x4x1.5 mm : LGA 16 L The LGA (Land Grid Array) is a type of surface mount packaging for integrated circuits that is notable for having the pins on the socket rather than the integrated circuits. An LGA can be electrically connected to a printed circuit board either by the use of socket or by soldering directly. • • • Features : 1)2.4v to 3.6v single supply operation 2) ±2g/±6g user selectable full scale 3) Output voltage, offset and sensitivity are ratio metric. to supply voltage 4) Low power consumption 5) Embedded self test 6)High shock survivability (10000g) Fabrication Details : The sensing element capable of detecting the acceleration is manufactured using a dedicated process developed by ST to produce inertial sensors and actuators in silicon. The IC interface is manufactured using an ST proprietary CMOS process with high level of integration. The dedicated circuit is trimmed to better n]match the sensing element characteristics Product Description : The LIS344ALH has a dynamically user selectable full scale of ±2g/±6g and it is capable of measuring accelerations over a maximum bandwidth of 1.8 kHz for all axes. the self test capability allow the user to check the functioning of the system. It is guaranteed to operate over an extended temperature range of -40oC to +85oC. Bottom view of LIS344ALH • Application 1) Gaming and Virtual reality input devices 2) Anti theft systems and inertial navigation 3) Appliances and robotics Submitted By: Rahul K K 2)MEMS PRESSURE SENSOR • Company name : Bosch Sensortec • Component Name : BMP 180 • Cost of product : 9 US$ • Dimensions : (3.6x3.8x0.93) mm3 • Packaging : LGA panel view of BMP 180 MEMS pressure sensor • Features : 1) Digital two wire (I²C, TWI, "Wire") interface 2) Wide barometric pressure range 3) Flexible supply voltage range (1.8V to 3.6V) 4) Ultra low power consumption (9.9 µW) up to 3µA current and optimum voltage as 3.3V. 5) Factory-calibrated . 6) Includes temperature sensor. 7) Low-profile with a small footprint. PARAMETER TECHNICAL DATA Pressure range (300-1100)hPa Average current consumption 3µA(ultra low power mode) 32µA(advanced mode) Power consumption 9.9 µW(ultra low power mode) Peak current 105.6 µW(advanced mode) 16.5 µW(standard mode) 650µA Stand by current 0.1 µA Supply voltage VDDIO Supply voltage VDD Pressure conversion time 1.62-3.6V 1.8-3.6V 5ms(standard mode) Operation temperature range Full accuracy data transfer rate (−40 + 85) C (0 + 65) C 3.4 Mhz,max Package type/pin numbers LGA/7 Package dimensions (3.6*3.8*0.93) • Fabrication Details • Product Description : Bosch Process. :-This is a breakout board for the Bosch BMP180 high-precision, low-power digital barometer. The BMP180 offers a pressure measuring range of 300 to 1100 hPa with an accuracy down to 0.02 hPa in advanced resolution mode. It is based on piezo-resistive technology for high accuracy, ruggedness and long term stability. These come factory-calibrated, with the calibration coefficients already stored in ROM. This breadboard-friendly board breaks out every pin to a 5-pin 0.1" pitch header. VCC can be from 1.8V to 3.6V and is 5V tolerant; typically it is run on a clean, regulated 3.3V supply. The analog and digital supplies are tied to a single header pin, but are separately decoupled. It connects to a microcontroller via I²C bus • PinConfiguration Pin No: • Bottom View Name : Function : • Applications : 1)In advanced mobile devices like smart phones, tablet PCs, sports devices etc. 2)Indoor navigation 3)GPS enhancement for dead-reckoning, slope detection etc. 4)Sport devices for altitude profile. 5) Weather forecast. 6)Vertical velocity indicator(rise/sink speed). Submitted By: Jinu M. Thomas 3)MEMS ACCELEROMETER • Company name • Component Name • Cost of product • Dimensions • Packaging • : Analog Devices, Inc : ADXL001 Accelerometer : 33 US$ : 4.6x5.2x2.2mm : LCC Features 1)High performance accelerometer ±70 g, ±250 g, and ±500 g wideband ranges available 22 kHz resonant frequency structure High linearity: 0.2% of full scale Low noise: 4 mg/√Hz 2)Frequency response down to dc 3)Full differential signal processing 4)High resistance to EMI/RFI 5)Complete electromechanical self-test 6)Output ratiometric to supply 7)Low power consumption: 2.5mA typical. 8)8-terminal, hermetic ceramic, LCC package • Fabrication details : Not Available • Product Description : The ADXL001 is a major advance over previous generations of accelerometers providing high performance and wide bandwidth. This part is ideal for industrial, medical, and military applications where wide bandwidth, small size, low power, and robust performance are essential. Using Analog Devices, Inc. proprietary fifth-generation iMEMs® process enables the ADXL001 to provide the desired dynamic range that extends from ±70 g to ±500 g in combination with 22 kHz of bandwidth. The accelerometer output channel passes through a wide bandwidth differential-to-single-ended converter, which allows access to the full mechanical performance of the sensor. The part can operate on voltage supplies from 3.3 V to 5 V. The ADXL001 also has a self-test (ST) pin that can be asserted to verify the full electromechanical signal chain for the accelerometer channel. The ADXL001 is available in the industry-standard 8-terminal LCC and is rated to work over the extended industrial temperature range (−40°C to +125°C). • Applications 1) 2) 3) 4) 5) Vibration monitoring Shock detection Sports diagnostic equipment Medical instrumentation Industrial monitoring Submitted By: Brijesh Varghese 4)MEMS ACCELEROMETER & GYROSCOPE • Company name : InvenSense • Component Name : MPU-6050 3-axis MEMS accelerometer & gyroscope • Cost of product : 5 US$ • Dimensions : 4x4x0.9 mm • Packaging : LGA with JEDEC type extension LGA 4x4x0.9 mm • Features : 1) 2.4v to 3.6v single supply operation 2) ±2g/±4/±8/±16g user selectable full scale 3) Output voltage, offset and sensitivity are ratio-metric. to supply voltage 4) Low power consumption 5) Tap detection 6) User-programmable interrupts 7) User programmable scale range of ±250, ±500, ±1000, and ±2000°/sec 8) Digitally-programmable low-pass filter 9) Gyroscope operating current: 3.6mA 10) Integrated 16-bit ADCs enable simultaneous sampling of gyros 11) Standby current: 5µA 12) 9-Axis Motion Fusion by the on-chip Digital Motion Processor (DMP) 13) Auxiliary master I2C bus for reading data from external sensors (e.g., magnetometer) 14) Digitally-programmable low-pass filters Top view of MPU-6050 • Fabrication details: Not available • Product description: Not available • Application 1) Location based services, points of interest, and dead reckoning 2) Handset and portable gaming 3) Motion-based game controllers 4) 3D remote controls for Internet connected DTVs and set top boxes, 3D mice 5) Wearable sensors for health, fitness and sports Toys Submitted By: Dhanish Vijayan 5) MEMS ACCELEROMETER • Company name :Analog Devices • Product name :ADXL345 • Cost of product :4.5-5 US$ • Dimensions :3mm*5mm*1mm • Packaging : LGA Features:- • 1) Ultralow power 2) User-selectable resolution 3) Free-fall detection 4) Supply voltage range: 2.0 V to 3.6 V 5) I/O voltage range: 1.7 V to VS 6) SPI (3- and 4-wire) and I2C digital interface 7) Wide temperature range (−40°C to +85°C) 8) 10,000 g shock survival 9) Pb free/RoHS compliant 10) Small and thin Fabrication Details: Not available. • Product description:- The ADXL345 is a small, thin, ultralow power, 3-axis accelerometer with high resolution (13-bit) measurement at up to ±16 g. Digital output data is formatted as 16-bit twos complement and is accessible through either a SPI (3- or 4-wire) or I2C digital interface. The ADXL345 is well suited for mobile device applications. It measures the static acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration resulting from motion or shock. Its high resolution (3.9 mg/LSB) enables measurement of inclination changes less than 1.0°. Several special sensing functions are provided. Activity and inactivity sensing detect the presence or lack of motion by comparing the acceleration on any axis with user-set thresholds. Tap sensing detects single and double taps in any direction. Free-fall sensing detects if the device is falling. These functions can be mapped individually to either of two interrupt output pins. An integrated, patent pending memory management system with 32-level first in, first out (FIFO) buffer can be used to store data to minimize host processor activity and lower overall system power consumption. Low power modes enable intelligent motion-based power management with threshold sensing and active acceleration measurement at extremely low power dissipation • Applications: Handsets Medical instrumentation Gaming and pointing devices Industrial instrumentation Personal navigation devices Submitted By: Mohammed Shaffi J 6)MEMS 3- AXIS ACCELEROMETER • Company name :Analog Devices • Component Name : ADXL330 • Cost of product : 5-6 US$ • Dimensions : 4x4x1.45 mm • Packaging : LFCSP_LQ • Product Description The ADXL330 is a small, thin, low power, complete 3-axis accelerometer with signal conditioned voltage outputs, all on a single monolithic IC. The product measures acceleration with a minimum full-scale range of ±3 g. It can measure the static acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration resulting from motion, shock, or vibration. • Features : 1)1.8v to 3.6v single supply operation 2) ±3g user selectable full scale 3) Low power consumption: 180 µA at VS = 1.8 V (typical) 4) Embedded self test 5)High shock survivability (10000g) 6) BW adjustment with a single capacitor per axis 7)Operating Temp. range -25 to+70 oC • Functional Block Diagram • Pin Configuration • Pin Description • Package description • Application 1) Gaming and Virtual reality input devices 2) Mobile devices like smart phones, tablet PCs, sports devices etc. 3) Gaming systems 4)Disk drive protection 5)Image stabilization. 6) Appliances and robotics Submitted By: Amanathulla M 7)MEMS E-COMPASS • Company name : ST Microelectronics • Component Name : LSM303DLHC • Cost of product : 15-20 US$ • Dimensions : 3x5x1 mm • Packaging : LGA 14 L • Power rating : 0.396mW at normal operation 3.6µW at low power mode. . • Product description: The LSM303DLHC is a system-in-package featuring a 3D digital linear acceleration sensor and a 3D digital magnetic sensor. LSM303DLHC has linear acceleration fullscales of ±2g / ±4g / ±8g / ±16g and a magnetic field full- scale of ±1.3 / ±1.9 / ±2.5 / ±4.0 / ±4.7 / ±5.6 / ±8.1 gauss. All full-scales available are fully selectable by the user. LSM303DLHC includes an I2C serial bus interface that supports standard and fast mode 100 kHz and 400kHz. The system can be configured to generate interrupt signals by inertial wake- up/free-fall events as well as by the position of the device itself. Thresholds and timing of interrupt generators are programmable by the end user on the fly. Magnetic and accelerometer parts can be enabled or put into power-down mode separately. The LSM303DLHC is available in a plastic land grid array package (LGA) and is guaranteed to operate over an extended temperature range from -40 °C to +85 °C. • Features 1) 3 magnetic field channels and 3 acceleration channels 2) From ±1.3 to ±8.1 gauss magnetic field full- scale 3) ±2g/±4g/±8g/±16g selectable full-scale 4) 16 bit data output 5) I2C serial interface 6) Analog supply voltage 2.16 V to 3.6 V 7) Power-down mode/ low-power mode 8) 2 independent programmable interrupt generators for free-fall and motion detection 9) Embedded temperature sensor 10) 6D/4D orientation detection • Fabrication Details: The sensing element is manufactured using a dedicated process developed by ST to produce inertial sensors and actuators in silicon. The IC interface is manufactured using an ST proprietary CMOS process with high level of integration. The dedicated circuit is trimmed to better match the sensing element characteristics Bottom view of LSM 303DLHC • Application 1) Compensated compass 2) Map rotation 3) Position detection 4) Motion-activated functions 5) Free-fall detection 6) Click/double click recognition 7) Pedometer 8) Intelligent power-saving for handheld devices 9) Display orientation 10) Gaming and virtual reality input devices 11) Impact recognition and logging 12) Vibration monitoring and compensation Submitted By: Amrutha K 8)MEMS CAPACITIVE TOUCH SCREEN CONTROLLER • Company name : ST MICTROELECTRONICS • Component Name : STMT05E • Cost of product : 5-6 US$ • Dimensions : (6 x 6 mm) • Packaging : QFN48 • Product Description : The STMT05E device represents a marked improvement over competing technologies by providing an optimal mix of low power, small size, feature flexibility with unmatched true multi-touch performance in a single-chip touchscreen controller. The FingerTip STMT05E uses a unique capacitance to voltage conversion acquisition engine to implement the S-Touch capacitive sensing method. Coupled with the flexibility offered by the internal processor engine, the entire touch-screen sensing solution can measure, classify and track a single finger touch with fast report rate and response times on 240 nodes. Built-in movement tracking engine tracks greater than 10 independent touch movements. The acquisition engine uses an optimal measurement approach to ensure almost complete immunity from parasitic capacitance on the receiver inputs (sense lines). The engine includes sufficient dynamic range to cope with touch-screens of different size and configuration. This offers great flexibility to use with multiple touchscreens with different ITO designs and overlay materials. One and two layer ITO sensors are possible using glass or PET substrates. The STMT05E's capacitive analog front-end provides enhanced noise suppression capabilities for various noise sources such as display, human body captured noise, system generated noise and severe common mode noise introduced by battery chargers. ST’s advanced capacitive sensing technology coupled with a powerful digital 32-bit DSP engine is able to address common mode noise to provide high level of noise immunity without reducing the overall touch performance in terms of response time, frame rate and power consumption. The device has external SYNC pin for LCD noise filtering for an "on-cell" display touch-screen technology. The synchronization of the signal acquisition with the LCD SYNC signal helps in removal of LCD noise. This benefits the touch module maker to employ glass screens with ITO to be used without any GND shield that can significantly reduce the cost of the touch module. The STMT05E supports multiple input types including stylus detection (up to 2 mm) for smooth handwriting capability on touch-screens while detecting and rejecting large area such as palm or hand. The device also supports touch-keys using the same ITO. • Features : 1)True multi-touch: – Independent XY tracking with 10 simultaneous touches in real time – Up to 12 force and 20 sense channels 2)Single chip solution: – Up to 5 inches screen size – Supports multiple touchscreen configurations including touch keys with no external components on touch channels 3) High SNR: – Common mode charger noise rejection up to 40 Vpp – Advanced filtering techniques for strong noise immunity 4) Fast report rate: > 150 Hz 5) High response time: < 2x report rate 6) Power consumption: – 7 mW in active mode (multi-touch) – 5 µW in sleep mode 7) Power supply scheme: – 2.8 V to 5 V AVDD and 1.8 V DVDD 8)32-bit RISC processor – Flexibility for customer code implementation – Allows customization of proprietary touch pattern and gestures 9) Large area recognition and rejection 10) Advanced signal processing and calibration: – Water recovery, self-calibration with autodrift compensation and fast start-up – Hardware coordinate scalar to match touch-screen and display resolution – Supports axis flipping and axis switch-over for portrait and landscape modes 11) Sensor types: – Works with plastic or glass sensors, with different types of sensor patterns with or without ground shield – Supports on-cell, laminated and touch-onlens touch display 12) Serial interface: – Supports high speed I2C and SPI – 3.3 V tolerant interface for I2C and SPI • Package description : Flat no-leads packages such as QFN (quad-flat no-leads) and DFN (dual-flat no-leads) physically and electrically connect integrated circuits to printed circuit boards. Flat no-leads, also known as micro lead frame (MLP) and SON (small-outline no leads), is a surface-mount technology, one of several package technologies that connect ICs to the surfaces of PCBs without through-holes. Flat no-lead is a near chip scale package plastic encapsulated package made with a planar copper lead frame substrate. Perimeter lands on the package bottom provide electrical connections to the PCB Flat no-lead packages include an exposed thermal pad to improve heat transfer out of the IC (into the PCB). Heat transfer can be further facilitated by metal vias in the thermal pad The QFN package is similar to the quad-flat package, and a ball grid array. 0.4mm pitch and 0.55 mm thick and up to 5 inches screen size • Application : Main application lies in touch screen mobile phone with stylus detection (up to 2 mm) for smooth handwriting capability on touch screens while detecting and rejecting large area such as palm or hand. The device also supports touch keys using the same ITO. Submitted By: Vaisakhan K R 9) MEMS GYROSCOPE • Company name : Analog Devices • Component Name : ADXRS646 • Cost of product : (58-64)US$ • Dimensions : 7×7 ×3 mm • Packaging : 32 Lead CBGA • Product description: The ADXRS646 is a high performance angular rate sensor (gyroscope) that offers excellent vibration immunity. The ADXRS646 offers superior vibration immunity and acceleration rejection as well as a low bias drift of 12°/hr (typical), enabling it to offer rate sensing in harsh environments where shock and vibration are present. An advanced, differential, quad sensor design provides the improved acceleration and vibration rejection. The output signal, RATEOUT, is a voltage proportional to angular rate about the axis normal to the top surface of the package. The measurement range is a minimum of ±250°/sec. The output is ratiometric with respect to a provided reference supply. Other external capacitors are required for operation. • Features 1. 12°/hr bias stability 2. Z-axis (yaw rate) response 3. 0.01°/√sec angle random walk 4. High vibration rejection over wide frequency 5. Measurement range extendable to a maximum of ±450°/sec 6. 10,000 g powered shock survivability 7. Ratiometric to referenced supply 8. 6 V single-supply operation 9. −40°C to +105°C operation 10. Self-test on digital command 11. Ultrasmall and light (<0.15 cc, <0.5 gram) 12. Temperature sensor output 13. • Complete rate gyroscope on a single chip Application 1) Computer pointing devices 2) Ship stabilizers 3) Severe mechanical environments 4) Robotics Submitted By: Nithin K Kurian 10) MEMS MAGNETIC SENSOR • Company name : MEMSIC • Component Name : MMC3416xPJ • Cost of product : 1.5 US$ • Dimensions : 1.6x1.6x0.6 mm • Packaging : LGA MMC3416xPJ magnetometer used in Wrist watches • Features 1)Fully integrated 3-axis magnetic sensor and electronic circuits requiring fewer external components 2) Superior Dynamic Range and Accuracy: ±16 G FSR with 16/14 bits operation 0.5 mG/2 mG per LSB resolution in 16/14 bits operation mode 1.5 mG total RMS noise Enables heading accuracy of ±1º 3) Max output data rate of 800 Hz (12 bits mode) 4) Ultra Small Low profile package (1.6x1.6x0.6 mm) 5) SET/RESET function Allows for elimination of temperature variation induced offset error (Null field output) Clears the sensors of residual magnetization resulting from strong external fields 6) On-chip sensitivity compensation 7) Low power consumption (140 µA at 7 Hz ) 8) 1µA (max) power down function 9) I2C Slave, FAST (≤400 KHz) mode • 10) 1.62 V~3.6 V wide power supply operation supported, 1.8 V I/O compatibility. Fabrication Details : Not available • Product description:- The MMC3416xPJ is a complete 3-axis magnetic sensor with on-chip signal processing and integrated I2C bus. The device can be connected directly to a microprocessor, eliminating the need for A/D converters or timing resources. It can measure magnetic fields within the full scale range of ±16 Gauss (G), with 0.5 mG/2 mG per LSB resolution for 16/14 bits operation mode and 1.5 mG total RMS noise level, enabling heading accuracy of 1º in electronic compass applications. Contact MEMSIC for access to advanced calibration and tilt-compensation algorithms. An integrated SET/RESET function provides for the elimination of error due to Null Field output change with temperature. In addition it clears the sensors of any residual magnetic polarization resulting from exposure to strong external magnets. The SET/RESET function can be performed for each measurement or periodically as the specific application requires. The MMC3416xPJ is packaged in an ultra small low profile LGA package (1.6 x 1.6 x 0.6 mm,) and with an operating temperature range from -40 º C to +85 º C. The MMC3416xPJ provides an I2C digital output with 400 KHz, fast mode operation. • Principle of operation:The Anisotropic Magneto-Resistive (AMR) sensors are special resistors made of permalloy thin film deposited on a silicon wafer. During manufacturing, a strong magnetic field is applied to the film to orient its magnetic domains in the same direction, establishing a magnetization vector. Subsequently, an external magnetic field applied perpendicularly to the sides of the film causes the magnetization to rotate and change angle. This effect causes the film’s resistance to vary with the intensity of the applied magnetic field. The MEMSIC AMR sensor is incorporated into a Wheatstone bridge configuration to maximize Signal to Noise ratio. A change in magnetic field produces a proportional change in differential voltage across the Wheatstone bridge However, the influence of a strong magnetic field (more than 25 G) in any direction could upset, or flip, the polarity of the film, thus changing the sensor characteristics. A strong restoring magnetic field must be applied momentarily to restore, or set, the sensor characteristics. The MEMSIC magnetic sensor has an on-chip magnetically coupled strap: a SET/RESET strap pulsed with a high current, to provide the restoring magnetic field. • Applications:1) Electronic Compassing in cellular phones and tablets, pedestrian navigation, gaming controls, wristwatches, in-vehicle GPS navigation 2) Linear and rotational position Sensing 3) Magnetic field measuring applications. Submitted By: Jithya K R 11)MEMS INERTIAL NAVIGATION SYSTEM • Company name : VectorNav Technologies • Component Name : VectorNav VN-200 GPS/INS • Cost of product : (5-6) US$ • Dimensions : Dimensions: 24 x 22 x 3 mm • Packaging : Surface Mount Package (30-pin LGA) • Product Description The VN-200, the world’s smallest & lightest, high-performance GPS-Aided Inertial Navigation System (GPS/INS).Combining an advanced GPS module with the latest in MEMS inertial & pressure sensor technology, the patent pending VN-200 provides unprecedented opportunities for embedded navigation in a footprint no larger than a postage stamp. • Features 1) On-Board Extended Kalman Filter Running at 200 Hz 2) Coupled Position, Velocity & Attitude Estimates 3) Dynamic Accuracy better than 0.25° in Pitch/Roll, 0.75°in Heading 4) On-Board Pressure Sensor & U-Blox GPS Receiver 5) Compatible with external GPS, pressure and magnetic measurements 6) Individually Calibrated for Bias, Scale Factor, Misalignment, & Gyro GSensitivity 7) Available with Full Temperature Compensation (-40°C to +85°C) 8) Weight: 3 grams • Functional Block Diagram • Packaging information : The VN-200 200 is the smallest, lightest, and lowest power GPS/INS available on the market. The sensor package and all electronics are housed in a rugged aluminum enclosure. Precision alignment holes are provided to ensure accurate installation. A 1010 pin locking connector is used to provide a reliable connection in severe high vibration or shock conditions. • Technical specifications: • Applications 1. Motor sports 2. Unmanned vehicles 3. Camera stabilization 4. Marine antenna stabilization Submitted By: By Aswin Shenoy A 12) MEMS MICROMIRRORS • Company name : Texas Instruments • Component Name : DLP 5500 • Cost of product : (4-5) US$ • Dimensions : 2D array (1024x768) of Aluminium micromirrors Micromirror size 16µm2 • Packaging : 149 Micro Pin Grid Array The PGA (Pin Grid Array) is a type of integrated circuit packaging. In a PGA, the package is square or rectangular, and the pins are arranged in a regular array on the under-side of the package. The pins are commonly spaced 1.27mm apart, may or may not cover the entire under-side of the package. • Features : 1) 3.6V single supply operation 2) Peak Current 750mA 3)power consumption 2.7W • Fabrication Details : 1) bulk micro-machining 2) Al - for mirror, Si nitride for isolation 3) CMOS substrate 4) SiO2 and Al are deposited on CMOS substrate Micro Pin Grid Array Mechanical Dimension • Application 3D Machine Vision 3D Optical Measurement Industrial and Medical Imaging Medical Instrumentation Digital Exposure systems Submitted By: Vani M 13) MEMS ACCELEROMETER • Company Name : Analog Devices • Component Name :ADXL193 (Silicon capacitive accelerometer) • Cost of Product 7.5 US$ • Dimensions :5x5x2 mm • Packaging : LCC The ADXL193 is a low power, complete single-axis accelerometer with signal conditioned voltage outputs that are all on a single monolithic IC. This product measures acceleration with a full-scale range of ±120 g. It can also measure both dynamic acceleration (vibration) and static acceleration (gravity). ADXL193 chip is shown below. It is a fourth- Fig: ADXL193 Chip generation surface micromachined MEMS accelerometer from ADI with enhanced performance and lower cost. Designed for use in front and side impact airbag applications, this product also provides a complete cost-effective solution useful for a wide variety of other applications. ADXL193 is temperature stable and accurate over the automotive temperature range, with a selftest feature that fully exercises all the mechanical and electrical elements of the sensor with a digital signal applied to a single pin. Its cost is `450. • Sensing principle: Capacitance change is the most widely used principle in microaccelerometers. A capacitor sensor contains a movable plate and a fixed plate. The input signal is applied to the movable plate. As the plate moves, the capacitance value change according to the equation is: Where, c is the capacitance Ԑ is the permittivity of dielectric medium A is the overlapping area d is the distance between electrodes A MEMS capacitor structure is shown in figure below. The component consists of a substrate and two electrodes separated by a cavity which forms the dielectric. Fig: A MEMS Capacitor • Principle of operation: In silicon capacitive accelerometer first the input acceleration signal is first converted to a position signal. The position signal is obtained from the inertial mass mass-spring spring arrangement. Then this position signal is measured using a differ differential ential capacitor arrangement. Simplified view is shown in the figure below. Fig: Simplified view of sensor under acceleration When the input acceleration signal is applied, due to inertia the mass in the mass-spring mass arrangement changes its position. The mass consists of movable plate that is made to change its position, according to input acceleration, in between fixed plates. This forms the differential capacitor arrangement. A picture of differential capacitor arrangement is shown below. Fig: A differential capacitor arrangement and equivalent circuit connection In a differential capacitor arrangement when the movable plate moves the distance between one pair of electrodes decreases while the distanc distancee between other pair increases. As a result both the capacitances C1 and C2 change. This causes a change in output voltage. • Fabrication details: Surface micromachining technology is used in the construction of ADXL193 accelerometer device. In this technol technology ogy the components are fabricated onto the surface of a substrate. Structures are fabricated on the surface using selective electroforming. In this technique a metal is electroplated onto substrate through a patterned photoresist. Suspended elements like cantilever which forms the movable electrode fixed to mass, is fabricated on the top of a previously deposited sacrificial layer. After the elements are formed, the sacrificial layer is removed leaving the sense element or structural layer. In this device polysilicon and silicon forms the structural layer. Silicon dioxide forms the sacrificial layer. Electrodes are made out of gold and silicon nitride forms the insulator material. Microscopic view of sensor region is shown below. Fig: Sensor region of capacitive accelerometer • Application : • Vibration monitoring and control • Vehicle collision sensing • Shock detection Submitted By: Renju Devassy 14)MEMS PIEZORESISTIVE PRESSURE SENSOR • Company name : Freescale Semiconductors • Component name : MPXV7007 (Piezoresistive pressure sensor ) • Cost of product : ( 6-7) US$ • Dimensions : 10×10×5 mm • Packaging : Thermoplastic surface mount packaging(PPS) Piezoresistive pressure sensors were some of the first MEMS devices to be commercialized. Compared to capacitive pressure sensors, they are simpler to integrate with electronics, their response is more linear and they are inherently shielded from RF noise. They do, however, usually require more power during operation and the fundamental noise limits of the sensor are higher than their capacitive counterparts. Historically, piezoresistive devices have been dominant in the pressure sensor market. The MPXV7007 piezoresistive transducers are state-of-the-art monolithic silicon pressure sensors designed for a wide range of applications, but particularly those employing a microcontroller or microprocessor with A/D inputs. This transducer combines advanced micromachining techniques, thin film metallization, and bipolar processing to provide an accurate, high level analog output signal that is proportional to the applied pressure. MPXV7007 chip is shown below. The device accepts an input pressure range of -7 kPa to +7 kPa. The output voltage varies from 0.5V to 4.5V. The cost of the device is `450. Fig: MPXV7007 CHIP • Sensing principle: Pieoresistive pressure sensors are one of the very first products of MEMS technology. Piezoresistivity is the change in electrical resistivity of a semiconductor or metal when mechanical strain is applied to it. The effect was first discovered by Lord Kelvin in the year 1856. When a strain is applied to conducting and semiconducting materials there is a change in inter-atomic spacing. This affects the bandgap, making it easier for electrons to be raised into the conduction band. This results a change in resistivity of the material. The piezoresistive effect of semiconductor materials can be several orders of magnitudes larger than the geometrical effect and is present in materials like germanium, polycrystalline silicon, amorphous silicon, silicon carbide, and single crystal silicon. The piezoresistive effect of semiconductors has been used for sensor devices. Many commercial devices such as pressure sensors and acceleration sensors employ the piezoresistive effect in silicon. Piezoresistors are resistors made from a piezoresistive material and are usually used for measurement of mechanical stress. They are the simplest form of piezoresistive devices. Fig: A MEMS Piezoresistor A MEMS piezoresistor which contains a silicon diaphragm onto which piezoresistors are mounted is shown in figure above. When the diaphragm experiences a pressure it deflects. This deflection causes a change in resistivity of the piezoresistors due to the strain experienced by them. Piezoresistors are mounted on the diaphragm in such a way that it experiences the maximum strain due to pressure in order to improve the sensitivity of the device. • Principle of operation: The pressure sensor is realized using four piezoresistors arranged on a membrane in Wheatstone bridge configuration as shown in figure below. The sensitivity depends on the orientation of piezoresistor and the location of piezoresistors on the membrane. In MPXV7007 all the piezoresistors are arranged on the surface of silicon membrane in a Wheatstone bridge format. The arrangement is shown below. In the arrangement under no pressure all the resistors R1, R2, R3 and R4 experience no strain. Hence all the resistors have the same resistivity. So the output voltage will be zero as the bridge is balanced. When a pressure is applied the diaphragm deflects and all the four resistors experience strain and an equivalent change in resistivity. R1 and R3 experience longitudinal strain where as R2 and R4 experience transverse strain. Hence the bridge will get unbalanced and there will be an output voltage. This is the basic working principle of piezoelectric pressure sensor. Fig: Arrangement of Piezoresistors on diaphragm • Fabrication details: In MPXV7007 bulk micromachining technology is used to construct Si membrane. Then onto the membrane piezoresistor patterns are formed using photolithography and oxide etching is done. Later dopants are diffused to form the piezoresistors. Aluminium is patterned to form the electrode contacts. Microscopic view of sensor region is shown below. Fig: Top view of Sensor region • Applications • Home appliances: Washing machines, Dishwashers, Vacuum cleaners etc. • Automotive applications: Oil level, Gas level, Air pressure detection. • Biomedical Applications: Blood pressure measurement. Submitted By: Athira Manohar PACKAGING SUMMARISATION: So far we have seen different mems components being adhered to different types of packages. Packaging description of different MEMS components is as follows. 1). LGA(Land Grid Array): The land grid array is a packaging technology with a square grid of contacts on the underside of a package. The contacts are to be connected to a grid of contacts on the PCB. Not all rows and columns of the grid need to be used. The contacts can either be made by using an LGA socket, or by using solder paste. LGA packaging is related to ball grid array (BGA) and pin grid array (PGA) packaging. Unlike pin grid arrays, land grid array packages are designed to fit both in a socket or be soldered down using surface mount technology. PGA packages cannot be soldered down using surface mount technology. In contrast with a BGA, land grid array packages in non socketed configurations have no balls and use a flat contact which is soldered directly to the PCB and BGA packages have balls as their contacts in between the IC and the PCBs. The LGA (Land Grid Array) is a type of surface mount packaging for integrated circuits that is notable for having the pins on the socket rather than the integrated circuits. An LGA can be electrically connected to a printed circuit board either by the use of socket or by soldering directly. 2).Chip Carrier Packages: In electronics, a chip carrier is one of several kinds of surface mount technology packages for integrated circuits. Connections are made on all four edges of a square package; the internal cavity for mounting the integrated circuit is large, compared to the package overall size. Chip carriers may have either J-shaped metal leads for connections by solder or by a socket, or may be lead-less with metal pads for connections. If the leads extend beyond the package, the preferred description is "flat pack". Chip carriers are smaller than dual in-line packages and since they use all four edges of the package can have a larger pin count. Chip carriers may be made of ceramic or plastic. Some forms of chip carrier package are standardized in dimensions and registered with trade industry associations such as JEDEC. Other forms are proprietary to one or two manufacturers. Sometimes the term "chip carrier" is used to refer generically to any package for an integrated circuit. Types of chip-carrier package are usually referred to by initialisms and include: • BCC: Bump Chip Carrier • CLCC: Ceramic Leadless Chip Carrier • Leadless chip carrier (LCC): Leadless Chip Carrier, contacts are recessed vertically. • LCC: Leaded Chip Carrier • LCCC: Leaded Ceramic Chip Carrier • DLCC: Dual Lead-Less Chip Carrier (Ceramic) • PLCC: Plastic Leaded Chip Carrier 3)Chip Scale Package: A chip scale package or chip-scale package (CSP) is a type of integrated circuit package. Originally, CSP was the acronym for chip-size packaging. Since only a few packages are chip size, the meaning of the acronym was adapted to chip-scale packaging. According to IPC’s standard J-STD-012, Implementation of Flip Chip and Chip Scale Technology, in order to qualify as chip scale, the package must have an area no greater than 1.2 times that of the die and it must be a single-die, direct surface mountable package. Another criterion that is often applied to qualify these packages as CSPs is their ball pitch should be no more than 1 mm. The concept was first proposed by Junichi Kasai of Fujitsu and Gen Murakami of Hitachi Cable. The first concept demonstration however came from Mitsubishi Electric. The die may be mounted on an interposer upon which pads or balls are formed, like with flip chip ball grid array (BGA) packaging, or the pads may be etched or printed directly onto the silicon wafer, resulting in a package very close to the size of the silicon die: such a package is called a wafer-level package (WLP) or a wafer-level chip-scale package (WL-CSP). Types of chip scale packages: Chip scale packages can be classified into the following groups: 1. Customized lead frame-based CSP (LFCSP) 2. Flexible substrate-based CSP 3. Flip-chip CSP (FCCSP) 4. Rigid substrate-based based CSP 5. Wafer-level level redistribution CSP (WL (WL-CSP) 4)Quad Flat No-Leads: QFN cross-sectional view The above figure shows the cross section of a Flat N No o lead package with a lead frame and wire bonding. There are two types of body designs, designs,punch singulation and saw singulation. singulation Saw singulation cuts a large set of packages in parts. In punch singulation, a single package is moulded into shape. The cross sec section shows a saw-singulated singulated body with an attached thermal head pad. The lead frame is made of copper alloy and a thermally conductive adhesive is used for attaching the silicon die to the thermal pad. The silicon die is electrically connected to the lead frame by 1-2 mil diameter gold wires. The pads of a saw singulated package can either be completely under the package, or they can fold around the edge of the package.
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