Checking Tool Contact Height in Solder-Ball Shear Tests

A solder-ball shear test should load the intended feature with a controlled tool path. The peak force alone does not describe where the tool contacted the ball or what ultimately failed. Preserve setup and failure images when comparing process conditions.

Define the joint and test method

Xyztec’s solder-ball shear guidance presents this as a specific bond-test application with controlled test tooling and failure evaluation. Use the applicable procedure and equipment guidance to establish the contact geometry for the actual joint.

Record alloy, pad construction, ball dimensions and prior assembly or conditioning history. Identify whether the sample is a package, test coupon or assembled-board feature. Similar ball diameters do not establish identical underlying joints.

Make the tool path reviewable

Review how the instrument establishes the reference height on a nonuniform specimen. A program copied from a flat coupon should not be assumed to track the intended position on a warped or stepped part.

Pair force with the failure surface

Save the force record and images for each tested location. Classify the observed failure using the agreed method, including uncertainty where the surface cannot be assigned confidently. A failure elsewhere in the construction can limit what the test establishes about the intended interface.

For example, if the tool contacts the substrate or an adjacent feature, review whether the recorded peak belongs to the intended shear event. Do not retain that value as a valid joint result merely because it is high.

Mark tested locations and choose the sequence so earlier destructive tests do not obstruct later tool access. Where the sequence changes the local support, have the test owner assess whether subsequent measurements remain representative.

Include the reference-surface image when the sample contains soldermask or other height steps. It should be possible to verify which surface defined the tool height without inferring that choice from the final damaged joint alone.

Compare matched populations

Keep test speed, contact height and failure classification aligned before ranking two soldering conditions. A change in failure mode may be as important as a change in average force.

State which requirement the result supports and what remains outside its scope. A short mechanical test does not independently establish service life under every thermal or mechanical exposure.

The wire-pull guide addresses another geometry-sensitive bond test, while dye-and-pull mapping supports a different destructive investigation.