The threading system of a semiconductor wire bonder directly affects wire bonding yield. Key components such as wire guide rollers, tension regulators, wire break detection sensor brackets, and EFO wand positioning seats require extremely high dimensional accuracy and surface quality. Hansheng Automation provides custom machining services for these non-standard parts based on customer drawings, supporting single-piece prototypes and small-batch production with tolerances controlled within ±0.002 mm and surface roughness below Ra0.2 μm.
During preparation, operators should confirm that the emergency stop button is functional, the air pressure is stable between 0.4 and 0.6 MPa, and the preheating program is activated so that the bonding head reaches 100–150°C. The wire material should be selected according to the required diameter, typically 15–50 μm for gold, aluminum, or copper wire. Anti-static wrist straps and dust-free gloves should be worn, and dedicated wire cutters and a tension meter should be prepared.
For the actual threading process, the wire spool is first mounted on the pay-off reel and the tension damper is adjusted to prevent loosening or jamming. The wire end is then passed in sequence through the wire guide roller, tension regulator, wire break detection sensor, and EFO wand positioning seat, before being inserted into the capillary hole of the bonding wedge. Threading should be performed gently to avoid stretching or deforming the wire. After the wire exits the capillary, it is trimmed to a length of 1–2 mm.
During parameter calibration, the tension is adjusted through the equipment control panel and verified with a tension meter, with the wire tension typically stabilized between 10 and 50 gf depending on wire diameter and bonding requirements. The EFO energy, bonding time, and bond force should be matched to the wire type. For example, gold wire bonding usually uses lower voltage and shorter time parameters.
For test bonding verification, a dry bonding test is performed first to check whether the ball shape is uniform and full, without insufficient bonding, tail lifting, or wire breakage. A standard test piece is then used for actual bonding, and a pull tester is applied to measure wire pull strength, which should generally be no less than 5 gf. Positional accuracy should also be confirmed.
For shutdown and safety, all threading components should be returned to their proper positions, the air supply and equipment power should be turned off, and the main power should be disconnected only after the bonding head has cooled. Wire debris in the work area should be cleaned up. During threading, contact with high-voltage EFO components must be avoided. If wire jamming or a wire break alarm occurs, the machine should be stopped immediately for inspection rather than forcibly pulling the wire.
