Patent ID: 7523848

Claim:
A system for measuring the size of free air balls for use with a wire bonder having a wire bonding tool and an Electric Flame Off (EFO) device, the system comprising: an imager disposed above a first image plane; a prism disposed below the imager; and at least one lens positioned between the first image plane and the prism in a first optical path, the at least one lens positioned between the prism and the imager and in a second optical path, the second optical path being different from the first optical path, wherein an image of a free air ball disposed at a lower portion of the wire bonding tool is provided to the imager via the prism and the at least one lens, the imager being positioned at a height above a height of the free air ball, the prism being positioned at a height below the height of the free air ball, and the at least one lens being positioned at a height between the height of the free air ball and the height of the prism.