Patent ID: 7780056

Claim:
A horn attachment arm for a bonding apparatus, a driving unit being fixed to one end of the arm and an ultrasonic horn being attached to the other end of the arm, the arm comprising: a fixing bracket provided on a side of the one end; an ultrasonic horn attaching bracket provided on a side of the other end; a pair of metal longitudinal structure members being connected and fixed to the fixing bracket and the ultrasonic horn attaching bracket; and an arm member comprising two horizontally extending flat plates stacked one above the other and fixed together, the two horizontally extending flat plates sandwiching together to fix, in a vertical direction, the fixing bracket, the ultrasonic horn attaching bracket and the pair of longitudinal structure members therebetween, wherein each of the horizontally extending flat plates of the arm member are constituted of a carbon fiber reinforced plastic having greater strength and rigidity in a longitudinal direction than in a width direction and connecting the fixing bracket and the ultrasonic horn attaching bracket; and wherein the carbon fiber reinforced plastic of the flat plates have a greater number of reinforced fibers in a longitudinal direction than in a width direction, thereby the rigidity and strength of the carbon fiber reinforced plastic in the longitudinal direction is several times greater than the rigidity and strength of a lightweight alloy such as a magnesium alloy while suppressing a linear expansion coefficient of said arm member to substantially zero.