MicrosystemsLaajuus (3 ECTS)

Objective

Microsystems are the 2nd revolution of the Silicon based technologies. Silicon is very special material because of its unique electrical, mechanical, optical and thermal properties. Different physical and mechanical functional properties can be integrated into the Silicon based microchip. Electromechanical and optical operations are mostly used in different microsystems.

Microsystem technology consists of microcircuits, micromechanics, micro-optics, microsensors and microfluidistics. Fabrication of microsystems are based on surface structures or so called 3D bulk technigues. Small micrometer size optical gas analyzers, micropumps and integrated sensors and high frequency resonators and filters are examples of existing applications. Main application fields are in Medical Instruments, Bioinstrumentation, Automotive , Consumer Electronics, Heavy Duty Vechiles, Avionics.

Goal for this course is to get familiar with microsystems and to be ready to use microsystem technology applications for different applications at work. Electrical output signal coupling of microsensors are studied.

Content

1. What are microsystems? Applications, markets and new technologies and solutions. Materials in micromechanics and special properties in them. Mechanical force coupling to capacitive electric signal in accelerometer (3D) and pressure sensor is studied. Micromechanical modeling and simulation with APLAC -, Multiphysics(COMSOL)- and MatLab Simulink tools
2. Sensor effects in microsystems are studied: resistivity, pietzoelectricity, pyroelectricity, pietzoresistivity, thermoelectric effect, Hall- effect and magnetoresistive effect. Actuators, adaptive magnetic materials, capacitive couplings and gas damping are explored. Differential capacitive coupling and pietzoresistive bridge connection are studied.
3. Microfluidistics and special applications: microfilters, microventiles, micropumps, micro size bublegenerators, flow in very small channels, EDL- layers close to microsurfaces, chemical sensors, DMD- micromirrors, . . .
4. Microfabrication technologies in Microsystems: Surface mounting of microsystems, 3D- bulk structures, thin films, lithography in microsensor applications, etching with plasma, DRIE and etching with older chemical methods, wire bonding and flip chip bonding and mounting of microsensors into the microsystems, hermetic packaging of Microsystems, NanoLCP material, CVD, LPE, VPE, MBE, cleanroom and ESD, microsystem structures filled with pressurized gas, …

Assessment criteria, satisfactory (1)

1. Is able to complete simple sensor modeling using APLAC- and Simulink tools. Student understands meaning of special properties of most commonly used sensor materials. Student knows the basic operation principle of capacitive accelerometer.
2. Is able define resistive and pietzoresistive sensor effect when temperature and/or mechanical stress are acting on the sensing elements. Student knows the most important sensor effects and main principles of operation.
3. Is able to define the size of microfluidistic flow channel. Is able to define operation principles of basic micro-fluidistic applications micropumps and microfilters.
4. Is able to define main principles and specific properties of the microfabrication technologies.

Assessment criteria, good (3)

1. Is able to complete modeling and simulation of microsystems used as case examples in this course with variation of parameters with APLAC - and Simulink application tools. Student understands function of dielectric and metal layers in microstructures. Student understands mechanical coupling with capacitive electrical systems in accelerometers and pressure sensors.
2. Student understands and knows the most of the microsystem sensor effects. Student understands the idea of the gas damping of microsystems. Student knows the differential capacitive coupling and understands its important role in accelerometer and inclinometer sensors.
3. Student knows special unique properties of DMD micromirror matrices. Student knows what are the possible problems with the DMD- mirrors.
4. Is able to define how the micro fabrication technologies are changing today and tomorrow. Is able to explain what is DRIE and compare it with the older chemical etching method. Student knows main principles of surface coating methods CVD, Sputtering, LPE, VPE and vacuum evaporation. Student knows basics in working cleanroom and ESD- protection methods.

Assessment criteria, excellent (5)

1. Is able to complete modeling and simulation of microsystem with given or own microstructure parameters with APLAC - and Simulink application tools. Is able to complete frequence response analysis or analyze the system with other external changeable variables.
2. Is able to take into account thermoelectric effect and change of resistivity in microstructures in case of temperature different temperatures. Student understands pietzoresistive measurement bridge operation in pressure sensor operation.
3. Is able to understand operation principles of chemical microsensors. Is able to understand the usage of optical methods as a part of microfluidistic application. Is able to understand how to avoid electrical striking due to static charges on surfaces in very small distances.
4. Student knows and understands that flip chip bonding technologies are now and in future one of the most important technologies in microstructures. Student knows and understands that the packaging technologies of microsystems are very important because that is the most expensive part of the products and because protection is needed for environmental effects.