A device can be tested at two levels during its manufacture. At the

wafer level automatic test equipment (ATE) accesses and tests die

while they are still an integral part of the wafer, that is, before

packaging into individual devices. At the device level the ATE

accesses the die after it has been packaged. While the test may be

the same, the method of physically contacting the die is different

depending on the test level. Wafers are accessed with precision

probes from a ‘probe card’. A robotic handler transfers packaged

devices to an interface board, which has an assembly of sockets to

take the packaged devices.