A process window defines combinations of settings that consistently meet visual, dimensional, and mechanical requirements. Designed experiments and capability data make the window repeatable across lots and tools.
Pull and shear strength reflect bond formation, wire properties, geometry, and failure mode. Improvement requires interpreting where the sample fails, not simply increasing the measured force.
Non-stick-on-pad defects can result from contamination, oxidation, poor capillary condition, weak ultrasonic transfer, pad damage, or incorrect setup. Structured checks prevent random parameter changes.
Bond force, time, and ultrasonic energy must work together to disrupt surface films and create intimate contact. Optimization should find the center of a stable region rather than a single best-looking setting.