Probe system with automatic control of contact pressure and probe alignment

摘要

A probe system for probing a device under test (DUT) includes a DUT support chuck for holding the DUT. A plurality of flexible probe needles are positioned along a "Z" axis that extends orthogonally from the surface of the DUT. Each probe needle is movable with respect to the DUT support chuck. A motor provides for relative movement, at least along the Z axis, between the probe needles and the DUT support chuck. A variable focus imaging system is positioned along the Z axis and provides image signals to a control processor. The control processor causes the variable focus imaging system to image the surface of the DUT and at least one probe needle. The control processor is responsive to a determined distance between focal planes containing the DUT surface and probe needle to cause the motor to move the probe needle and the DUT surface into physical engagement. The motor is further controlled to provide a relative movement distance between the probe needle and the DUT that is greater than the determined distance between the focal planes, thereby enabling a predetermined contact pressure to be obtained.