Microelectronics is a field of electronics engineering that involves the design and fabrication of electronic components on a minuscule scale
These devices are typically fabricated using microelectromechanical systems (MEMS) or microelectronic mechanical systems (MEMS), which are small structures that can be integrated into electronic circuits
Transistor
A fundamental building block of microelectronics
Benefits of Microelectronics
Miniaturization
Power efficiency
Advancements in computing
Innovation across industries
Economic impact
Vacuum tubes
A device used to control the flow of electric current using a vacuum in a sealed container
Disadvantages of vacuum tubes
Size and weight
Warm-up time
Heat
High power supply voltages
Point-to-point wiring
Solid-state device
An electronic device in which electricity flows through solid semiconductor crystals rather than through vacuum tubes
Integrated circuit (IC)
Transistors and diodes are often combined with resistors, capacitors and other components to create the integrated circuit, a solid-state device that binds the individual components to a thin substrate of semiconductor material
Large inductors and transformers cannot be fabricated on an IC
Wafer preparation
1. Crystal growth
2. Single Si crystal ingot
3. Crystal trimming and diameter grind
4. Flat grinding
5. Wafer slicing
6. Edge rounding
7. Lapping
8. Wafer etching
9. Polishing
10. Wafer inspection
Oxidation
The process of adding oxygen to the Si wafer
Diffusion
The process of adding impurities atoms from a region with high concentration to a region of low concentration
Ion implantation
Introduces impurity atoms in the crystal semiconductor by applying accelerated atoms at a low temperature and high energy
Chemical-vapor deposition (CVD)
Used to produce thin film of protective layers on the wafer surface
Photolithography
Used to pattern thin films on the substrate by protecting certain areas during successive fabrication processes
Metallization
The process of coating a metal layer on the metallic surface or non-metallic surface
Packaging
The last stage of the IC fabrication process where the finished silicon wafer or chips are sealed with epoxy or plastic to prevent it from atmospheric dust
vfBGA Assembly
Very Fine-pitched Ball Grid Array
Types of ICs
Monolithic
Film
Hybrid
Assembly Process Flow
1. FrontofLine (FOL)
2. DiePreparation
3. DieAttach
4. Wire bond
5. InternalVisualInspection
6. EndofLine (EOL)
Monolithic ICs
ICs that are formed completely within a semiconductor substrate
Die-prep
Wafer Incoming Monitor
Wafer Wash
Wafer Tape
Backgrind
Mount Before Detape
Wafer Saw
Die Visual Inspection
Wafer Thickness Monitor
Wafer Incoming Monitor
Inspects the wafer to ensure that the wafer has not been damaged during transit
To establish an inspection procedure for separation of defect-clustered wafers
Diffusion method
A method used to form monolithic ICs
Rejected dice are marked with inked dots
Epitaxial
A method used to form monolithic ICs involving growing a thinly doped epi layer over a thickly-doped silicon substrate
Film ICs
ICs where film can only be used as passive circuit components, such as resistors and capacitors
Thin film
Fabrication methods include vacuum evaporation and cathode sputtering
Wafer
A thin slice of single crystal silicon which is used as the basic substrate for the fabrication of ICs
Die
The individual semiconductor element of integrated circuit (also known as chip) or a piece of silicon containing integrated circuit
Wafer Wash
Cleans the wafers thoroughly from any foreign materials before covering with tape
Thick film
Fabrication method includes screen printing
Wafer Tape
Provides tape onto the wafer top surface to prevent any debris or particles from getting in contact with the front side of the wafer during the backgrind process
Hybrid ICs
ICs fabricated by combining two or more circuit types, such as film and semiconductor circuits, or a combination of one or more circuit types and discrete elements
Backgrind
Reduces the thickness of the wafer (die backside)
Then WASH to ensure no residues of silicon debris is clinging at the back surface of the wafer before detape process
Wafer De-tape
The process of removing or peeling off the tape after the backgrind process
The primary advantage of hybrid microcircuits is designflexibility
Wafer Thickness Monitor
Measures the thickness of the wafer
Ensures required thickness is achieved
Then WASH to ensure no foreign materials are left on the surfaces of the wafer before wafer mount
MountBeforeDetape (MBD)
The process of mounting the wafer onto the Nitto tape to hold the wafer in place before cutting or before the wafer is sawn
Wafer Saw
To cut the wafer into individual die or the process of separating the dice from the wafer