How is wire bonding integrity assessed according to IPC-A-610?

The assessment of wire bonding integrity according to IPC-A-610 is primarily focused on ensuring that the bonds made between wires and their respective pads or leads are strong enough to withstand mechanical stress and maintain electrical connectivity. Option B points to two crucial metrics: tensile strength and resistance.

Tensile strength tests evaluate the mechanical bond's physical robustness by determining how much force the bond can withstand before failing. This is essential, as wire bonds endure various stresses during operation, including thermal cycling and vibration. Resistance measurements assess the electrical performance of the bond, ensuring that the conductivity remains within acceptable limits, which is vital for the overall function of the electronic assembly.

Visual inspection may identify obvious flaws but does not provide a definitive assessment of bonding strength or electrical integrity. The age of components or the type of solder used does not directly assess wire bonding integrity and is not a standard method outlined in IPC-A-610 for this purpose. Therefore, tensile strength and resistance are the key factors for ensuring that wire bonds perform reliably in their intended applications.