Agilent Technologies 93000 SOC Series Training Manual page 476

Measuring Pin Margins 17-1 Measuring Pin Margins
17-1 Measuring Pin Margins
Overview
To get reliable results while testing your devices on the production
floor, you must use tester settings that take into consideration the
margins caused by tester and device.
The pin margin tool can measure the margins of your Device-Under-
Test (DUT) on a pin by pin base or on a group base. These margins are
normally measured by a passing functional test of the testflow. The pin
margin test measures the minimum lower and upper margin of the pins
or pin groups.
The main purpose of the pin margin test is to ensure that you have
enough headroom with your tester to test correctly the current device
in a volume production on multiple test sites. In some cases the pin
margin test can also be used to find a single hardware resource (edge
or level) that can be moved to make a failing device pass.
N O TE
The margins can only be measured if the functional test with the actual
settings passes. Only if you suspect a certain pin or pin group to cause
the fail result it might be reasonable to use a failing setting to identify
this pin or pin group.
A good way to find critical hardware resources is to determine the
margins of pin groups first to detect the groups where critical pins are
located. In a second step the margins of group members of those groups
can be measured to identify critical pins. In a last step the margins of
edges and levels of these selected pins can be measured. This 'Top-
Down approach' reduces the length of the test report and the test time.
The pin margin test does not characterize your DUT. To characterize
the DUT you should use other tools like the Shmoo Tool or the test
functions.
The pin margin test characterizes the tester and the test program. It
helps you to find suitable tester settings for your production test envi-
ronment. In this way you will avoid failing devices unnecessarily.
476
Agilent 93000 SOC Series User Training Part 1, October 2004