A technique for electrical measurement of ball bond location

A test structure incorporating a special bond pad has been developed to make an electrical measurement of the location of a ball bond on a bonding pad. The pad can also be used to measure the electrical resistance of a wire and its bond interfaces (Kelvin measurement). The structure consists of an aluminum bond pad with each corner connected to another bond pad. Four of these 5-pad sense elements are incorporated into small square test die ´modules´. For any specific application test dice can be cut from the wafer in multiples of the module. The authors describe the method and theory of location measurement, and present data to verify the operation of the sensors.<>