Probe head for loopback testing and methods of forming the same

Abstract

A probe card for a circuit probe test system and methods of fabrication thereof. The probe card includes a substrate portion, and a probe head including a guide plate located below the substrate portion and having a plurality of openings through the guide plate, and a conductive trace on the guide plate that extends between a pair of the openings. A plurality of probe pins extend through the openings through the guide plate, where a pair of probe pins are electrically connected by the conductive trace to form a loopback signal path. Accordingly, the loopback signals may be routed through the conductive trace located on and/or within the guide plate rather than through the substrate portion of the probe card. This may significantly reduce the total length of the loopback signal path, which may thereby improve the signal integrity (SI) during loopback testing of a device-under-test.