This module is at intermediate level and prepares final year manufacturing and design engineering students to work in the Microfabrication and MEMS (Micro Electro Mechanical Systems) industries. Starting with the production of electronic grade silicon (EGS), the module teaches the micro fabrication processes that turn this EGS into Integrated circuits and MEMS devices. In particular it examines in detail Crystallography, Thermal Oxidation, Thin Film Deposition, Photolithography, and Etching. It covers the fundamentals of the controlled flow of charged particles at the micro level within electronic devices, doping and the manufacture of logic gates. A number of case studies, such as the manufacture of micro pressures sensors and cantilevers are examined in detail bringing together all the elements of microfabrication. Maximisation of yields and production together with IC and MEMS packaging are also covered. Cleanroom classification, the control of air movement and quality, filtering systems, cleanroom concepts, validation and monitoring and cleanroom energy conservation are all covered. Students fabricate MEMS devices in a series of cleanroom labs which familiarises them with relevant cleanroom protocols and procedures useful for industry.
Production of Silicon: Electronic Grade, Siemens process, Czochralski process, Ingot preparation, Wafer slicing, Wafer preparation, IC/MEMS design issues, IC/MEMS manufacturing issues, Wafer Testing, maximisation of yields.
Semiconductors: Drift / Diffusion, conduction in semiconductors, Intrinsic/extrinsic semiconductors, PN junctions, MOSFETS configuration and operation.
Crystallography: Amorphous/crystalline/polycrystalline structures, The unit cell, Properties of silicon, Crystal planes, Miller index, Importance of crystal orientation.
Thermal Oxidation: Importance /properties of silicon dioxide, Oxide growth kinetics.
Thin Film Deposition: Vacuum Technology, Physical Vapour Deposition (Evaporation, Sputtering), Chemical Vapour Deposition.
Photolithography: Masking, Photoresists, Exposure, UV / electron beam /ion beam/ x-ray, Contact/ Proximity/ Projection lithography systems.
Etching: Surface / Bulk etching, Etchant materials, Selectivity, Wet etching, Isotropic/Anisotropic, Dry etching, Chemical vapour Deposition, Reactive Ion etching, Deep RIE
Application of MEMS devices: Types of MEMS, MEMS sensors, Inertial sensors, Accelerometers, Gyroscopes, DLP/GLV systems, application of bio-MEMS, Lab-on-a-chip devices, bio-MEMs for analysis/diagnostics/monitoring/drug delivery/cell culture.
MEMS fabrication: Access to microfabrication facility to manufacture MEMS devices such as micro pressure switches and bioMEMs devices.
Cleanroom Technology: Federal / British standards/ ISO, EU Practice, Class limits. Air velocity in cleanrooms, Patterns, Uni/non-directional, Mixed, Filtration, Room static pressure, Temperature & humidity, Noise & vibration, Recirculation air systems, Make-Up Air systems, Concept-1/2/3/4 , Energy conservation and waste management, Validation & monitoring. Recommended tests and commissioning. Clean room safety and ethics
