Importance

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Abstract

Improved ultrasonic wire bonders, and improvements to ultrasonic wire bonding transducers that are used with such ultrasonic wire bonders. The improvements to the ultrasonic wire bonding transducer includes driver-node mounting of the transducer and a clamping arrangement for a bonding tool in the transducer. The driver-node mounting of the transducer is achieved by mounting it in the ultrasonic bonder such that a 3/4--wavelength distance is created between a mounting bracket of the transducer and a distal end of the transducer at which the bonding tool is disposed. As a result, vibrational problems caused by the transducer not being located at the node are eliminated. The driver-node mounting aspect of the present invention provides a shorter overall transducer and concentrates the mass at the driver end for less tool impact, and reduces manufacturing variables related to achieving a one-half wavelength distance between the driver node and the transducer node. The mounting arrangement is achieved by using a set screw, and more particularly a soft point set screw, opposite a drilled-out back wall of the transducer. The set screw directly secures the bonding tool or engages a clamping shoe that radially secures the bonding tool to the end of the transducer. As a consequence, rigid clamping of the bonding tool is achieved. Therefore, the clamping force exerted on the bonding tool is in line with the direction of ultrasonic motion imparted to the bonding tool. The present clamping arrangement improves the transfer of ultrasonic energy that excites the bonding tool into transverse (flexural) vibration.

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First Claim