IPC CID Complete Exam 2026/2027 –
Detailed Questions & Verified Correct
Answers (Graded A+)
What is an unsupported hole? - ANSWER -A hole in the printed board that does
not contain plating or other conductive reinforcement
What is a supported hole? - ANSWER -A hole that has the inside surfaces plated
or otherwise reinforced
What is a buried via? - ANSWER -A via that extends only between conductive
layers with no exposure to the outside world
How do you measure annular ring on an external layer? - ANSWER -Including
the plating the hole.
How do you measure annular ring on an internal layer? - ANSWER -Excluding
the plating in the hole.
What are minimum annular ring requirements defined by? - ANSWER -Internal
supported, external supported and external unsupported holes.
What is the most important factor in determining the minimum land size for a
hole? - ANSWER -The max drill hole diameter
What are each of the following: a+2(b+c)+d - ANSWER -Min land size=max drill
hole+2(min annular ring+etchback)+manufacturing
What is tolerance? - ANSWER -The amount of variation allowed in a dimension
or location
What is breakout? - ANSWER -Drilled hole breaking out of the edge of the
copper land
What is breakout acceptability? - ANSWER -Varies among class, where different
amounts of breakout are allowed.
, What is the MMC and LMC? - ANSWER -Can have dimensions given in a range,
where MMC is most material condition and LMC is least material condition
What is the recommended electrical spacing from board edge? - ANSWER -16
mils PLUS the electrical requirement
What is it called when a land is only present to balance the construction of the
board? - ANSWER -Nonfunctional lands
What is the clearance on nonfunctional lands? - ANSWER -0.25 mm (10 mils)
What is thermal relief? - ANSWER -Thermal relief is intended to remove
sufficient copper to avoid heatsinking during the soldering processes while still
meeting minimum current carrying requirements
How do you calculate thermal web size? - ANSWER -0.6*(1/number of
webs)*landsize
What does CTE stand for and what are its units? - ANSWER -Coefficient of
thermal expansion and ppm/C
What is the CTE for copper, brass and aluminum? - ANSWER -Copper: 17-18
ppm/C; brass: 19 ppm/C; aluminum: 24 ppm/C
What is special about thermal vias? - ANSWER -They must be connected to
board-level planes
What does MTBF mean? - ANSWER -Mean time between failures; a higher
mean time means your board is more reliable
What is the difference between burn-in testing and HAST? - ANSWER -HAST is
usually destructive while burn-in is non-destructive and works to find infant
mortality issues
What is a test coupon? - ANSWER -Companies find them beneficial and
incorporate them into board production panels to not waste a good board in
production
What is true of test probes? - ANSWER -They must make contact with every net,
and can be ensured with the supplied net-list
Detailed Questions & Verified Correct
Answers (Graded A+)
What is an unsupported hole? - ANSWER -A hole in the printed board that does
not contain plating or other conductive reinforcement
What is a supported hole? - ANSWER -A hole that has the inside surfaces plated
or otherwise reinforced
What is a buried via? - ANSWER -A via that extends only between conductive
layers with no exposure to the outside world
How do you measure annular ring on an external layer? - ANSWER -Including
the plating the hole.
How do you measure annular ring on an internal layer? - ANSWER -Excluding
the plating in the hole.
What are minimum annular ring requirements defined by? - ANSWER -Internal
supported, external supported and external unsupported holes.
What is the most important factor in determining the minimum land size for a
hole? - ANSWER -The max drill hole diameter
What are each of the following: a+2(b+c)+d - ANSWER -Min land size=max drill
hole+2(min annular ring+etchback)+manufacturing
What is tolerance? - ANSWER -The amount of variation allowed in a dimension
or location
What is breakout? - ANSWER -Drilled hole breaking out of the edge of the
copper land
What is breakout acceptability? - ANSWER -Varies among class, where different
amounts of breakout are allowed.
, What is the MMC and LMC? - ANSWER -Can have dimensions given in a range,
where MMC is most material condition and LMC is least material condition
What is the recommended electrical spacing from board edge? - ANSWER -16
mils PLUS the electrical requirement
What is it called when a land is only present to balance the construction of the
board? - ANSWER -Nonfunctional lands
What is the clearance on nonfunctional lands? - ANSWER -0.25 mm (10 mils)
What is thermal relief? - ANSWER -Thermal relief is intended to remove
sufficient copper to avoid heatsinking during the soldering processes while still
meeting minimum current carrying requirements
How do you calculate thermal web size? - ANSWER -0.6*(1/number of
webs)*landsize
What does CTE stand for and what are its units? - ANSWER -Coefficient of
thermal expansion and ppm/C
What is the CTE for copper, brass and aluminum? - ANSWER -Copper: 17-18
ppm/C; brass: 19 ppm/C; aluminum: 24 ppm/C
What is special about thermal vias? - ANSWER -They must be connected to
board-level planes
What does MTBF mean? - ANSWER -Mean time between failures; a higher
mean time means your board is more reliable
What is the difference between burn-in testing and HAST? - ANSWER -HAST is
usually destructive while burn-in is non-destructive and works to find infant
mortality issues
What is a test coupon? - ANSWER -Companies find them beneficial and
incorporate them into board production panels to not waste a good board in
production
What is true of test probes? - ANSWER -They must make contact with every net,
and can be ensured with the supplied net-list
