A semiconductor automatic test equipment, a backing apparatus for use therein, and methods for operating these equipments

A probe card 110 connects several die on a wafer 104 to automated test equipment (ATE) via a probe card holder 107. Spacer supports 109 are fixed between probe card and holder, with an additional rigid backing plate 106 attached to the probe card. Levelling actuators 111 are used until the backing plate connects with the holder at a single point, when linear actuators 108 hold the plate in secure connection so all reference contacts 112 are sufficiently electrically connected to the wafer. The actuators are located in either the probe card holder or probe card backing plate. Measurement unit 103 provides information about the parallel levelling of wafer and probe card, using for example optical imaging, confocal microscope, mechanical measurement or ultrasonic sensor.