Loop-back probe test and verification method

A method of using a loop-back test device to verify continuity between loop-back probes electrically connected to each other on a probe card, the loop-back test device including a first conductive region electrically connected to a substrate, a second conductive region electrically isolated from the substrate, the second conductive region spaced apart from the first conductive region such that when a first loop-back probe contacts the first conductive region a second loop-back probe contacts the second conductive region, and a reference mark arranged on a side of the substrate opposite the first conductive region, the reference mark aligned with the first conductive region to indicate a position of the first conductive region, the method comprising:

• placing the first loop-back probe in electrical contact with the first conductive region;
• placing the second loop-back probe in electrical contact with the second conductive region;
• measuring continuity between the substrate and the second conductive region;
• the loop-back test device further including a reference mark arranged on a side of the substrate opposite the first conductive region, the reference mark aligned with the first conductive, region to indicate a position of the first conductive region, the method comprising:
• aligning the loop-back test device on a chuck of a probe card analyzer such that the reference mark is in a field of view of an optical detector of the analyzer;
• obtaining via the optical detector an image of the reference mark;
• determining a position of the reference mark within the image;
• and
• establishing a position of the first conductive region based on the determined position of the reference mark in the image.

A method of using a loop-back test device to verify continuity between loop-back probes having a direct electrical connection to each other on a probe card, the loop-back test device including a first conductive region electrically connected to a substrate, a second conductive region electrically isolated from the substrate, the second conductive region spaced apart from the first conductive region such that when a first loop-back probe contacts the first conductive region a second loop-back probe contacts the second conductive region, the method comprising:

• placing the first loop-back probe in electrical contact with the first conductive region;
• placing the second loop-back probe in electrical contact with the second conductive region;
• and
• measuring continuity between the substrate and the second conductive region.