Tweezer tips are the “gripping jaws” which you need for USB tweezers. This tool is ideal for solder and gold balls and to perform Cold Bump Pull tests. They are also usable for some other applications like copper pillar.
The cavities in the jaws reform the ball to apply the maximum test force with minimal effect to the bond area. They should reform the ball to a “mushroom” shape, ideally with the “stem” of the mushroom shape being larger or the same diameter as the bond. This reforming process has a far smaller effect to the bond area than a standard shear test where ball deformation occurs over typically 30% of the bond diameter before achieving the peak test force.
These tips are compatible with Sigma and Classic bond testers. Besides a range of standard tips, we design custom tips to suit many different geometries for multiple applications.
Using the Cold Bump Pull test method, it is not always possible to effectively grip the balls. The ratio of ball diameter to height is an important metric when determining the testability of a part. The threshold ratio of testability with tweezers is roughly defined by diameter / height < 2.