Patent ID: 7004373

Claim:
An apparatus for detecting failure of wire fed through a wire feed bore in an ultrasonic bonding tool of an ultrasonic bonding machine to properly bond to a bond site, said apparatus comprising; a. wire feed means including a despooler for feeding bonding wire to an inlet aperture of a wire feed bore through an ultrasonic bonding tool, said despooler comprising: i. wire supply spool means, ii. drive motor means for rotatably supporting said wire supply spool means, iii. outlet wire guide eye means which has therethrough an aperture through which wire from said wire supply spool means is supplied to said entrance opening of said wire feed bore through said bonding tool, iv. means for forming a slack portion of wire of predetermined slack length F between said wire supply spool means and said outlet wire guide eye means, v. wire sensor means for providing a detection signal when the length of said slack portion of wire is shortened by a predetermined amount in response to wire being drawn from an outlet aperture of said wire feed bore of said bonding tool, and vi. motor actuator means responsive to said sensor detection signal in rotating said wire supply spool drive motor means a predetermined angular increment to thereby pay out wire from said wire supply spool means in a forward direction towards said outlet wire guide eye means, thereby restoring said slack portion of wire to said predetermined length F, b. monitoring means for monitoring the length of wire fed by said wire feed means to said bonding tool, c. distance determining means for determining a direction vector distance R between a pair of bond sites comprising a source bond site BS and a destination bond site BD on a workpiece, d. logic means for confirming that a length of wire C drawn from said wire feed supply spool means by said bonding tool in forming a wire interconnection bonded at a source end of said wire to said source bond site and at a destination end of said wire to said destination bond site is at least as large as a length L which is at least as large as said vector distance R between said bond sites, and e. said logic means outputting a first, pass signal if C is at least as large as L, and a fail signal if C is less than L.