Electronics Manufacturing Flashcards
(23 cards)
what is lithography
technology for rapid and accurate manufacture of complex/repetitive components
requirements of packaging for IC
- connections for signal lines and power
- physical structure to support and protect the circuit
- mechanisms for heat removal
moore’s law
the number of transistors on a chip will double about every two years
rent’s rule
number of IOs that a circuit needs will increase with complexity
- I = bC^p
TAB Bonding
- tape automated bonding
- relies on flexible tape instead of lead-frame
- IC bond pads gold bumped
flip chip assembly
smallest, lightweight
short electrical path = good performance
flip chip process
- wafer bumping - apply UBM, apply solder to form bumps
- align and reflow
- apply underfill
comparison bond pads:
Wire: standard
TAB: Gold
flip chip: Nickel
comparison speed
Wire: slow
TAB: fast
flip chip: fast
comparison tooling/set up costs
wire - low
TAB - high
flip chip - medium
comparison electrical performance
wire - ok
TAB - better
flip chip - best
comparison size
wire - ok
TAB - ok
flip chip - the best
comparison yield
wire - ok
TAB - good
flip chip - poor
comparison PCB compatibility
wire - needs Au
TAB - good
flip chip - excellent
SMT
surface mount technology
smaller
cheaper
higher pin counts
lithography expose time
= sensitivity/intensity
PCB manufacture process single sided
drill - plating resist - etching - solder resist - curing
types of processes double sided PCB manufacture
eopper electroplating
- photoresist lamination
Multilayer PCB
- more track per unit area
- replacement of interwiring = smaller, lighter, cheaper
soldering
joining of two materials using a molten metallic filler (with lower melting point)
soldering temp
< 400 degrees
brazing temp
> 400 degrees
yield calculation
= e^(-AD)
A = area D = defect density
