Here is the abstract you requested from the Automotive_2012 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|How to double cpk in wirebonding by just doing it right|
|Keywords: Bond Testing, automotive electronics, improving test results|
|Wire-bond testing for thin wires is mostly done by pull-testing, with a much smaller share of tests performed by shear-testing. The correct and standard way of pull-testing requires the measured pull strengths to be corrected for geometry influences which are caused by differing loop heights. This stems from the fact that the force felt by the bond itself is equal to the force measured at the pull hook if - and only if - the wire bridge forms angles of 30° at both the source and the destination bonds at the moment of breakage. For higher loops (with corresponding angles over 30°), the measured force is too high while for lower loops the pull strength is under-measured. Because typical circuits contain many different loop heights, the measured values will differ even if the bonds themselves are perfectly identical, giving an unnecessarily low cpk. We present an automatic pull test process which corrects for these influences and, in addition, has the huge attraction of requiring no operator assistance. Therefore the operator influence on the test result is avoided, and the testing cost is lowered considerably while raising the quality.|
|Dr Josef Sedlmair,
F&K Delvotec Semiconductor, Austria