That is done using ultrasound, which is generated by a box called a pulse-generator that is similar in size to a pacemaker box, but is inserted lower down in the chest (see illustration).

Aiming at the technology demand of advanced copper interconnection, the effect of pulse current density on cu layer properties such as resistance, crystal size and surface roughness were investigated.

Then the amplitude threshold is established combined with detection probability. The method of ascertaining pulse number threshold is analyzed according to orientation requirement and target size.