Cell phones, pocket PCs and other consumer products require the maximum functional integration of
memory, DSPs, ASICs, RFs, MEMs and other devices in the smallest footprint and lowest profile.
As a result, die stack package which consists of more than two dies interconnected by wire bond in
one package has been developed and manufactured. But it has some issues such as compound yield
loss, test complexity and KGD issue related to IC cost.
POP basically consists of pre-tested good packages interconnected using solder balls or wires and
has advantages over die stack package such as high final test yield and flexibility of procuring top
and bottom packages independently from multiple sources.