Qualification of the Assembly Process of Flip-Chip BGA Packages ...

4.3.1.3 Leakage Test
Texas Tech University, Nivetha Shivan, May 2012
Ideally, the input pin in a DUT would have infinite impedance and no current would flow
into or out of the pin; but in reality the input pin will have very large (finite) impedance
which results in a very small value of current flowing into or out of the pin. This small
current is called leakage current. The purpose of this test is to measure this leakage
current that flows into or out of the functional pins. This test targets to detect the physical
defects in the DUT which is a result of the process variations.
Input leakage low test (IIL) is done by applying VDDmax to all the pins and using PMU
(parametric measurement unit) to force 0V to the individual input pins and measuring the
resultant current. The magnitude of the measured current should be below the spec limit.
Input leakage high test (IIH) is done by applying 0V to all the pins and using PMU
(parametric measurement unit) to force VDDmax to the individual input pins and
measuring the resultant current. The measured current should be below the spec limit.
The purpose of the output leakage test is to measure the leakage current that flows into or
out of the output pins when it is in the off state.
The output leakage low test is done by making the output and I/O pins to go to tristate
(high impedance state; making the output to go to this state allows no output signals to be
generated) and applying 0V to the individual output pins using PMU and measuring the
resultant current. The magnitude of the measured current should be below the spec limit.
The output leakage high test is done by making the output and I/O pins to go to tristate
and by applying VDDmax to the individual output pins using PMU and measuring the
resultant current. The measured current should be below the spec limit.
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