Patent ID: 8800843

Claim:
A bonding apparatus comprising: a base unit; an ultrasonic horn vibrating longitudinally in resonance with a vibration of an ultrasonic vibrator, the ultrasonic horn comprising a bonding tool attaching portion, an ultrasonic horn body comprising a first location coinciding with a node of a resonant vibration and a second location coinciding with an anti-node of the resonant vibration, and a flange provided at the first location; a bonding tool attached at the second location; a bonding arm attached rotatably to the base unit in such a manner as to move a tip end of the bonding tool in a direction toward and away from a bonding target, the bonding arm comprising a front end portion having a flange mounting surface at which the flange of the ultrasonic horn is securely affixed to the bonding arm, a rear end portion having a center of rotation, a load sensor attached between the flange mounting surface and the center of rotation, and a thin plate-like connection positioned between two narrow slits functioning as a rotation hinge is formed between the front end portion and the rear end portion; a vibration load detection device comprising a filter and a computer for determining the bonding state; said load sensor detecting a vibration load at the tip end of the bonding tool in a longitudinal direction of the ultrasonic horn; said filter passing a signal within a frequency range around a frequency of the ultrasonic vibrator once said load sensor detects the vibration load, said computer determining after the start of bonding, a period of amplitude increase during which the amplitude of the vibration load at the tip end of the bonding tool in the longitudinal direction of the ultrasonic horn increases, and a period of amplitude stability after the period of amplitude increase during which the amplitude is approximately constant, said periods representing a mid-bonding state in which an initial ball formed at the tip end of the bonding tool is deformed and bonded to the bonding target, and in response to determining such periods, the computer outputs a mid-bonding state signal, said computer further determining that the bonding is completed upon detecting a predetermined period of time after detecting the amplitude becoming larger than the amplitude during the period of amplitude stability, the computer then outputting a bonding completion signal, the computer further determining the state of bonding between the initial ball formed at the tip end of the bonding tool and the bonding target based on detecting a change in the amplitude of the detected vibration load at the tip end of the bonding tool in the longitudinal direction of the ultrasonic horn, and thereafter outputting a signal based on the state of bonding.