Patent ID: 8091761

Claim:
A bonding apparatus comprising: a bonding head movable in an X direction and a Y direction with an X-Y table; a bonding arm for moving a bonding tool in an approaching and retreating direction with respect to a pad of a semiconductor chip, the bonding arm being attached to the bonding head and having the bonding tool attached to a tip thereof; a camera for capturing an image of the pad and a bonded ball bonded to the pad, the camera being attached to the bonding head with an optical axis of the camera being offset by a predetermined distance in the X direction and the Y direction with respect to a center line of the bonding tool in bonding operation; and a control unit for controlling a position of a central axis of the bonding tool in the X direction and the Y direction based on an offset amount and the image of the pad captured with the camera, the control unit comprising: an outline obtaining means for obtaining each of sides of the pad in a quadrilateral shape and an outline of the bonded ball by processing the image captured with the camera; a gap length obtaining means for obtaining each gap length between each of the sides of the pad and each portion of the outline of the bonded ball closest to corresponding sides of the pad; and an offset correcting means for correcting the offset amount based on each gap length obtained by the gap length obtaining means.