Sensing probe for determining location of conductive features

A system for determining the coordinate location in the X and Y directions of a set of electrically conductive surface features on an insulating substrate comprising:

• a support for said substrate,
• at least two sensor heads mounted above said support for said substrate,
• each of said sensor heads having a mounting base that supports a plurality of elongated flexible flat electrically conductive sensing blade elements, insulation means electrically insulating adjacent sensing blade elements from each other, the flat ends of said blade elements terminating in a plane parallel to the top surface of said substrate for contact with said electrically conductive surface features, said blade elements arranged so that the center to center distance of at least two elements is less than the width of one of said conduction features, and a means to hold said sensing blade elements in a slightly bowed position such that each successive element has a greater bow, said bowed position of said blade elements permitting retraction of individual blade elements without affecting adjacent unretracted blade elements to permit independent limited movement of the contact portions of said individual blade elements,
• a first of said sensor heads arranged with the minor axis of the blade elements oriented orthogonally to the said X direction,
• a second of said sensor heads arranged with the minor axis of said blade elements oriented orthogonally to said Y direction,
• a means to move said sensor heads in the Z direction into engagement with said substrate,
• a means associated with each sensor head to determine whether or not said blade elements are electrically shorted by contact with said surface features,
• said first and said second sensor heads in operation providing an indication of the location of selected surface features resulting from the shorting of the blades of said sensors by said surface features.