MICROELECTRONICS EXAM
QUESTIONS & ACTUAL CORRECT
ANSWERS 100%
mesh count - Correct Answer ✔✔ number of wires per inch. we use 325 mesh
thixotropic - Correct Answer ✔✔ dual viscosity, thin enough to pass through screen,
thick enough to stick
conductor pastes - Correct Answer ✔✔ gold(Au), silver(Ag), copper(Cu)
angle of attachment - Correct Answer ✔✔ 90 degrees
gold - Correct Answer ✔✔ reliable, expensive, tends to react w/ other metals. must use
alloys to minimize interactions. corrosion resistance
silver - Correct Answer ✔✔ good conductor, economical, interactions, very poor solder
leach resistance, tendency to migrate (dendrite growth), use alloys w/ Pd, Pt to
minimize migration problems and increase resistance to solder leach, alloys significantly
reduce electrical conductivity
copper - Correct Answer ✔✔ low cost, good conductor, excellent solder leach
resistance, degradation (oxidation), copper films must be processed in an oxygen-poor
environment, films tend to degrade over time when used w/ PbSn solder
alumina (Al2O3) - Correct Answer ✔✔ most common, inexpensive, wide range of
purities (96% thick film, 99% thin film)
beryllia (BeO) - Correct Answer ✔✔ power apps due to high thermal conductivity, high
freq. apps due to its low dielectric constant
aluminum nitride (AlN) - Correct Answer ✔✔ high thermal conductivity, TCE match w/
silicon
TCE - Correct Answer ✔✔ thermal coefficient of expansion
soldering - Correct Answer ✔✔ reflow soldering, conveyor belt w/ heated zones
epoxy - Correct Answer ✔✔ conductive, nonconductive
eutectic bonding - Correct Answer ✔✔ bonding of materials to achieve lower temp,
melts at much lower temp than individual melting temps
, wire bonding - Correct Answer ✔✔ thermocompression (heat), ultrasonic (friction),
thermosonic (combo of first two)
TAB - Correct Answer ✔✔ tape automated bonding, typically made of copper
flip chip - Correct Answer ✔✔ solder bumping
PTF - Correct Answer ✔✔ polymer thick film, electroluminescence, transparent
conductors (ITO-indium tin oxide)
thick film process - Correct Answer ✔✔ CAD, photolithography, printing, dry/firing,
component attachment, testing
thick film prints - Correct Answer ✔✔ 10-15 micrometers
1 mil - Correct Answer ✔✔ 25 micrometers
CMOS - Correct Answer ✔✔ complimentary metal oxide semiconductor
growth deposition - Correct Answer ✔✔ wet oxidation, dry oxidation
wet oxidation - Correct Answer ✔✔ high temps/water vapor. grows faster, porous, not
dense
dry oxidation - Correct Answer ✔✔ high temps/oxygen gas. grows slower, very dense
thermal evaportaion - Correct Answer ✔✔ makes use of VAC environment,
inexpensive, some materials are difficult to deposit due to high melting temps, not same
versitility. buffer layer
VAC environment - Correct Answer ✔✔ minimize contamination, uniform deposition,
reduces the melting evaporation temp
boat type - Correct Answer ✔✔ refractory metals w/ high melting temps. do not interact
w/ charge (W, Mo, Ta)
Sputtering - Correct Answer ✔✔ gas enters electric field, knocks source material off
target. deposited on substrate. considerably more expensive, versatility
reactive sputtering - Correct Answer ✔✔ a reactive gas (Ar) can be mixed with inert gas
to cause chemical reaction at substrate
magnetron sputtering - Correct Answer ✔✔ uses magnetic fields to control the
deposition
QUESTIONS & ACTUAL CORRECT
ANSWERS 100%
mesh count - Correct Answer ✔✔ number of wires per inch. we use 325 mesh
thixotropic - Correct Answer ✔✔ dual viscosity, thin enough to pass through screen,
thick enough to stick
conductor pastes - Correct Answer ✔✔ gold(Au), silver(Ag), copper(Cu)
angle of attachment - Correct Answer ✔✔ 90 degrees
gold - Correct Answer ✔✔ reliable, expensive, tends to react w/ other metals. must use
alloys to minimize interactions. corrosion resistance
silver - Correct Answer ✔✔ good conductor, economical, interactions, very poor solder
leach resistance, tendency to migrate (dendrite growth), use alloys w/ Pd, Pt to
minimize migration problems and increase resistance to solder leach, alloys significantly
reduce electrical conductivity
copper - Correct Answer ✔✔ low cost, good conductor, excellent solder leach
resistance, degradation (oxidation), copper films must be processed in an oxygen-poor
environment, films tend to degrade over time when used w/ PbSn solder
alumina (Al2O3) - Correct Answer ✔✔ most common, inexpensive, wide range of
purities (96% thick film, 99% thin film)
beryllia (BeO) - Correct Answer ✔✔ power apps due to high thermal conductivity, high
freq. apps due to its low dielectric constant
aluminum nitride (AlN) - Correct Answer ✔✔ high thermal conductivity, TCE match w/
silicon
TCE - Correct Answer ✔✔ thermal coefficient of expansion
soldering - Correct Answer ✔✔ reflow soldering, conveyor belt w/ heated zones
epoxy - Correct Answer ✔✔ conductive, nonconductive
eutectic bonding - Correct Answer ✔✔ bonding of materials to achieve lower temp,
melts at much lower temp than individual melting temps
, wire bonding - Correct Answer ✔✔ thermocompression (heat), ultrasonic (friction),
thermosonic (combo of first two)
TAB - Correct Answer ✔✔ tape automated bonding, typically made of copper
flip chip - Correct Answer ✔✔ solder bumping
PTF - Correct Answer ✔✔ polymer thick film, electroluminescence, transparent
conductors (ITO-indium tin oxide)
thick film process - Correct Answer ✔✔ CAD, photolithography, printing, dry/firing,
component attachment, testing
thick film prints - Correct Answer ✔✔ 10-15 micrometers
1 mil - Correct Answer ✔✔ 25 micrometers
CMOS - Correct Answer ✔✔ complimentary metal oxide semiconductor
growth deposition - Correct Answer ✔✔ wet oxidation, dry oxidation
wet oxidation - Correct Answer ✔✔ high temps/water vapor. grows faster, porous, not
dense
dry oxidation - Correct Answer ✔✔ high temps/oxygen gas. grows slower, very dense
thermal evaportaion - Correct Answer ✔✔ makes use of VAC environment,
inexpensive, some materials are difficult to deposit due to high melting temps, not same
versitility. buffer layer
VAC environment - Correct Answer ✔✔ minimize contamination, uniform deposition,
reduces the melting evaporation temp
boat type - Correct Answer ✔✔ refractory metals w/ high melting temps. do not interact
w/ charge (W, Mo, Ta)
Sputtering - Correct Answer ✔✔ gas enters electric field, knocks source material off
target. deposited on substrate. considerably more expensive, versatility
reactive sputtering - Correct Answer ✔✔ a reactive gas (Ar) can be mixed with inert gas
to cause chemical reaction at substrate
magnetron sputtering - Correct Answer ✔✔ uses magnetic fields to control the
deposition
