Cavity shear #
Cavity Shear tools have a semi-cylindrical recess (cavity) that distributes the shear load on a ball over a much larger surface area. This reduces ball deformation and increases the test result values. Although the test result increases, it also promotes more bond (IMC) failures. This occurs because the ball is not progressively deformed and sheared by the high stress concentrations produced by standard shear. More bond failures provide more data on the strength of the bond rather than the shear strength of gold.
Ideal solution for testing Ultra Fine Pitch Gold Balls #
The passivation layer in Ultra Fine Pitch applications often limits the shear height causing low test results as the tool simply cuts the top off the bond. Cavity Shear minimizes this affect by distributing the test load over the ball. The advantages of Cavity Shear also apply to Solder Ball applications.
Test features #
- Increases test values
- Minimizes ball deformation
- Minimizes test influence on bond strength
- Sensor accuracy ±0.075%
- Enables testing with increased shear height