Xandex Kinematic Docking

Extreme precision, planarity and repeatability in prober-tester docking

Xandex is one of the first American-based companies to create and introduce automated solutions for docking and interfacing automated test equipment. Xandex has developed innovative docking solutions for both prober/tester docking at wafer sort and tester/handler docking at final test. Many of the company’s early development projects were driven by specific customer requests for custom “aftermarket” solutions. The resulting designs provided improved alignment and stability over existing solutions and significantly reduced dock/undock cycle time.

Currently, Xandex Kinematic Docking solutions are being implemented during the research and development phase of new test equipment platforms. Instead of being an after market solution, Xandex Kinematic Docking, when integrated into interface and test head design is bringing a new level of accuracy, repeatability, planarity and ease of use to today’s latest semiconductor test platforms.

Original Xandex Kinematic Docking Concept

The traditional wafer sort docking scheme aligns and secures the test head to the prober using mechanical latching schemes consisting of cams, screw threads or clamps. Planarity and alignment of the test head to the prober are difficult to achieve, and the latching forces can be inconsistent, resulting in probe to pad mis-alignment and probe card deflection.

When a spring probe interface tower is sandwiched between the test head back plane electronics board and a Device Under Test (DUT) board (or probe card) using mechanical latching schemes, the compression force applied can be uneven. This causes one or both boards to deflect as the spring probes are compressed. The resulting deflection is apparent in intermittent or inconsistent electrical contact between test head electronics and the probe card, and in addition, can cause the probe needles to contact the device pads unevenly.

Xandex Kinematic Docking (patent pending) is a means of isolating the test head in all six possible degrees of motion, relative to the prober. This is accomplished by resting the weight of the test head onto three docking locations installed on a modified prober head plate. Corresponding locations in an interface structure installed on the test head mate with the locations on the prober. Each docking location is oriented to the other two locations so that when the test head is resting on all three docking points, its movement is completely isolated and completely planar to the prober.

Kinematic Docking is ideally suited to both Xandex vacuum interface and XZIF (Xandex Zero Insertion Force) interface technology. Since Kinematic Docking is extremely repeatable and planar, the probe card is located and aligned precisely to the wafer. Board deflection forces are greatly reduced or eliminated, as are time consuming alignment and docking procedures.

Xandex Kinematic Docking point on V4400 Test system.

In addition to docking the test head to a wafer prober, Kinematic Docking can also be used to mate a DUT board, such as a probe card, to a test interface with near perfect planarity and repeatability. This is especially significant when a high level of parallelism is desired.  Instead of latching the probe card in place, which can result in mis alignment and deflection, Kinematic Docking insures that the probe card is aligned with precision without the possibility of planar misalignment.

Xandex has also designed  Kinematic Docking with latching features that lock the docking points on the test head and prober together. The locking feature does not improve Kinematic Docking performance, but is a significant safety feature in earthquake prone areas of the world.

Kinematic Dock and Lock Module