Consigned Material Sourcing and Counterfeit Escape Risk Controls
Consigned material sourcing requires strict incoming package checks, chemical decapsulation, and clear contract risk allocation to prevent counterfeit escapes.
Wire Bond Pull Test
Breaking Strength
Destructive mechanical evaluation measures intermetallic bond integrity by applying a vertical lifting force until the connection separates from the metallization pad. A micro-tensile tester hooks a calibrated loop of fine tungsten or gold filament directly above the capillary footprint and raises the tool at a controlled velocity. Operators apply this screening method to sample boards originating from high-volume automated wedge or ball attach stations to verify intermetallic compound growth.
Excessive force rips aluminum pads clean from the silicon substrate while insufficient force leaves untouched loops that fail later under thermal cycling stress.
Failure Mode
Fracture locations categorize the underlying metallurgical weakness by distinguishing whether the separation occurred at the heel, along the span, or directly at the weld interface. Technicians examine recovered hook sites under high-magnification stereomicroscopes to record whether breakage stems from ultrasonic energy starvation during thermosonic bonding or incorrect stage temperature. Brittle intermetallic phases form underneath the gold ball when excessive thermal exposure creates undesirable voids inside the alloyed zone.
Shear forces and tensile loads interact differently across copper and gold metallurgy because harder substrates demand tighter process control windows during the initial impact stage.
Process Verification
Statistical process control charts track breaking values across production lots to catch tool wear before micro-cracks propagate through the entire semiconductor package. Engineers set baseline thresholds according to wire diameter and loop length specifications defined in military and commercial reliability standards. Automated load cells capture gram-force measurements continuously and trigger line stoppages whenever running averages deviate from established acceptance criteria.
Sample sizes follow strict frequency rules established during initial package qualification to maintain consistent product quality without overtesting delicate assemblies.