A high-precision GSG probe planarization method based on direct current signal

Since the GSG (ground-signal-ground) probe has three pins, it needs planarization before the wafer test. To ensure the reliability of the RF wafer test, a new high-precision GSG probe planarization method is first proposed based on DC (Direct Current) analysis. The angle-force model of the GSG probe contact and separation process is derived, which is based on the analysis of the collected real-time force and electrical data using a designed force sensing system, and voltage measuring circuit. The results show that when the GSG probe is in contact with the substrate and away from the substrate, the relationship between the angle and force model is a primary function and a quadratic function respectively. The angle of the GSG probe can be obtained by substituting the force of the change points of voltage and resistance into the angle and force model. In addition, the smaller the difference between the minimum force at two-pin contact and three-pin contact of the GSG probe, the smaller the angle of the GSG probe. This method can provide a method and idea for the automatic planarization of GSG probes.