SEMICONDUCTOR DEVICE FABRICATION AN OVERVIEW Presented to EE September 2015 by Stan Burns MWAH 153

OUTLINE èWhat is a Monolithic (“Single Stone”) Integrated Circuit (IC)? èFabrication and Integrated Circuit Overview èDimensions and Units èHistorical Perspectives èState-of-the-Art in Size and Density-Moore’s “Law” èMaterials èPhotolithography èBasic process sequence èTypical Device Cross-Sections èOther Devices and Technologies èBasic Processing Steps Summary èPackaging èChallenges and Opportunities in the Semiconductor Industry For EE Graduates

3 IC Fabrication Overview Procedure of Silicon Wafer Production Raw material ― Polysilicon nuggets purified from sand Crystal pulling Si crystal ingot Slicing into Si wafers using a diamond saw Final wafer product after polishing, cleaning and inspection A silicon wafer fabricated with microelectronic circuits

DIMENSIONS AND UNITS  1 micrometer (1  m) = m = cm è1 Å = m = cm (Å =Angstrom)  10,000 Å = 1  m = 1000 nm è1 nanometer (1 nm) = m = 10 Å  Wavelength of visible light 0.4  m(violet) to 0.7  m(red) {400 nm to 700 nm, 4,000 Å to 7,000 Å }  1 mil = inch = 25.4  m èSheet of notebook paper about 4 mils  1 human hair = 75  m to 100  m = 75, ,000 nm èAtomic spacing in a crystal ~ 3 to 5 Å  Fingernail growth rate about 1-3  m/hour ( Not personally verified ) èAggressive production minimum feature sizes, tens of nm, nm used in the iPhone 6S A9 microprocessor.

Stanley G. Burns UMD-ECE

<128 GByte Best Buy 27 Sept. 2015) 16 nm

BASIC PROCESSING STEPS Design Then Repeated Application Of: Oxidation Nitridation Photolithography Wet Etching (Chemical) Dry Etching (Plasma) Diffusion Evaporation Sputtering Plasma Assisted Deposition Ion Implantation Epitaxy Many Processing Steps are at temperatures to 1200°C

OTHER DEVICES AND TECHNOLOGIES èThin-Film Transistors (TFT) èDisplays-Liquid Crystal Displays (LCD), Plasma, LED Backlit, etc. èPhotonic-Light Emitting Diodes (LED), Organic Light Emitting Diodes (OLED), LASERS, Optical Chips, etc.) èPhotovoltaics-Conventional Crystalline and Flexible Thin- Film èDevices and Systems on Flexible Substrates èMicro-Electro-Mechanical Systems (MEMS) integration of mechanical elements, sensors, actuators, and electronics on a common silicon substrate through microfabrication technology. Electronics are fabricated using integrated circuit (IC) process sequences (e.g., CMOS, Bipolar, or BICMOS processes) è Micromechanical components are fabricated using compatible "micromachining" processes that selectively etch away parts of the silicon wafer or add new structural layers to form the mechanical and electromechanical devices.

Challenges in the Semiconductor Industry For EE Graduates èDesign devices èDesign circuits and systems èDevice modeling èSystem design and fabrication èCircuit/system simulations èTestability èMaterials (Si, III-V, Graphene èHow small? Nanomaterials? èHow large? Wafer Scale? èSpeed and performance, for analog, digital and mixed- mode applications èIncreased functionality è Biological integration è Optoelectronic integration è Displays è Sensors including “Wearables) è MEMs (Design/Application) è Non-traditional substrates è Packaging è Process development è Process Control è “Tool” and plant design è Cradle to grave materials handling