SEMICONDUCTOR DEVICE FABRICATION AN OVERVIEW Presented to EE October 2012 by Stan Burns MWAH 153

OUTLINE èWhat is a Monolithic Integrated Circuit (IC)? èDimensions èState-of-the-art in size and density èMaterials èBasic process sequence èPhotolithography èDefine some key terms èTypical Device Cross-Sections èPackaging èChallenges and Opportunities in the Semiconductor Industry For EE Graduates

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 )  Aggressive production minimum feature sizes ~0.022 to 0.12  m è i.e. tens of nm  Research and some prototypes<  m = < 22 nm

Integrated Circuit Overview

Stanley G. Burns UMD-ECE

<$50

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.

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

EE Student Challenges in the Semiconductor Industry èDesign devices èDesign circuits and systems èDevice modeling èSystem design and fabrication èCircuit/system simulations èTestability èMaterials èHow small? Nanomaterials? èHow large? èSpeed and performance, for analog, digital and mixed- mode applications èIncreased functionality èBiological integration èOptoelectronic integration èDisplays èSensors èMEMs (Design/Application) èNon-traditional substrates èPackaging èProcess development èProcess Control è“Tool” and plant design èCradle to grave materials handling