Quality control of ultrasonic bonding tools using a Scanning White Light Interferometer

Working surface of the ultrasonic bonding wedge must adhere to tight specifications to permit strong and repeatable ultrasonic wire bonding. Even minute changes in the wedge surface reduce the yield, especially when bonding to fragile materials. Consequently the ability to determine the profile of the bonding surface of the wedge could contribute to improved yield. We propose to use Scanning White Light Interferometry (SWLI) to measure the working surface topology of these wedges. SWLI measures complex surfaces with nanometer height resolution.