Ultrasonic horn

An ultrasonic horn, which is an ultrasonic horn used in a wire bonding apparatus, comprising:

• a vertical vibration generating portion in which a first ultrasonic vibrator is mounted inside such that a vibration direction is a front-rear direction;
• a horn portion extending forward from the vertical vibration generating portion, amplifying an ultrasonic vibration generated by the vertical vibration generating portion, and to which a bonding tool is mounted at a front end portion;
• and
• a torsional vibration generating portion extending rearward from the vertical vibration generating portion,
• wherein the torsional vibration generating portion comprises:
• a rod-shaped body extending rearward from the vertical vibration generating portion;
• a pair of vibration members arranged axisymmetrically around a longitudinal central axis of the rod-shaped body and having a mass smaller than the rod-shaped body;
• a pair of second ultrasonic vibrators axisymmetric around the longitudinal central axis of the rod-shaped body and sandwiched between the rod-shaped body and each of the vibration members such that a vibration direction is a circumferential direction;
• and
• a pair of pressurizing mechanisms respectively compressing each of the second ultrasonic vibrators sandwiched between the rod-shaped body and each of the vibration members and pressurizing each of the second ultrasonic vibrators.